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1.
Arch. cardiol. Méx ; 90(3): 274-283, Jul.-Sep. 2020. tab, graf
Article in Spanish | LILACS | ID: biblio-1131044

ABSTRACT

Resumen Objetivo: Comprobar las diferencias morfológicas y funcionales del corazón en dos poblaciones latinoamericanas con distintas características raciales y condiciones de vida. Métodos: Mediante el ecocardiograma transtorácico se obtuvieron datos de 206 personas: 103 del poblado de Atahualpa, Ecuador (nivel del mar, edad x̄ 75 ± 4.2 años, 53 mujeres) y 103 habitantes de la Ciudad de México (altitud de 2,300 m, edad x̄ 75 ± 4.2 años, 52 mujeres). Resultados: Las diferencias significativas entre Atahualpa y la Ciudad de México fueron frecuencia cardíaca, 66 vs. 80; diámetro diastólico ventricular izquierdo, 40.8 vs. 42.7; grosor del tabique, 9.8 vs. 11.6; pared posterior, 10.2 vs. 11.8; volumen-latido en centímetros cúbicos, 53.0 vs. 46.6; volumen auricular Izquierdo, 25.8 vs. 33.6; presión sistólica de la arteria pulmonar, 27.1 vs. 42.0; gasto cardíaco, 3.1 vs. 4.8; cociente E/Ea, 6.4 vs. 9.2; área mitral, 3.4 vs. 3.0. El comparativo de la función diastólica entre Atahualpa y la Ciudad de México fue: tipo 0: 2 vs. 1; tipo 1: 96 vs. 81; tipo 2: 5 vs. 20; tipo 3: 0 vs. 1. Conclusión: Las características ecocardiográficas que identifican los cambios adaptativos del corazón en Atahualpa coinciden con personas que viven a nivel del mar y con buena actividad física y en México con los habitantes de grandes altitudes y expuestos a contaminación ambiental. La función sistólica del ventrículo izquierdo fue similar en ambas poblaciones, lo que indica que los cambios adaptativos hacen posible que el corazón sea eficaz en diferentes circunstancias del ecosistema.


Abstract Objective: To compare morphological and functional differences of the heart in two Latin American populations with different ethnicity and living conditions. Methods: Using transthoracic echocardiogram we obtained data on 206 individuals: 103 from Atahualpa, Ecuador (living at sea level, mean age: 75 ± 4.2 years, 53 women) and 103 inhabitants from Mexico City (living at 2300 m above sea level, mean age: 75 ± 4.2 years, 52 women). Results: Significant differences between Atahualpa and Mexico were: Heart rate 66 versus 80 x’, left ventricular diastolic diameter 40.8 versus 42.7, septum thickness 9.8 versus 11.6, posterior wall 10.2 versus 11.8, stroke volume cc 53.0 versus 46.6, left atrial volume 25. 8 versus 33.6, systolic pressure of the pulmonary artery 27.1 versus 42.0, cardiac output 3.1 versus 4.8, E/Ea ratio 6.4 versus 9.2, and mitral area 3.4 versus 3.0. Comparison of diastolic function between Atahualpa and Mexico was: Type 0; 2 versus 1. Type 1; 96 versus 81. Type 2; 5 versus 20 and Type 3; 0 versus 1. Conclusion: Echocardiographic characteristics that identify adaptive changes of the heart in Atahualpa are coincident with people living at sea level and with good physical activity, and Mexico City, with inhabitants living at high altitudes and exposed to environmental pollution. The systolic function of the left ventricle was similar in both populations, indicating that adaptive changes allow the heart to be effective in different circumstances of the ecosystem.


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Aged, 80 and over , Adaptation, Physiological/physiology , Echocardiography , Heart/diagnostic imaging , Exercise , Cross-Sectional Studies , Ecuador , Environmental Exposure/adverse effects , Environmental Pollution/adverse effects , Altitude , Mexico
2.
Biol. Res ; 53: 08, 2020. tab, graf
Article in English | LILACS | ID: biblio-1100914

ABSTRACT

BACKGROUND: Rice is the staple food of many people around the world. However, most rice varieties, especially widely grown indica varieties and hybrids, are sensitive to cold stress. In order to provide a basis for the utilization of a common wild rice (CWR, Oryza rufipogon Griff.) named 'Chaling' CWR in cold-tolerant rice breeding and deepen the understanding of rice cold tolerance, the cold tolerance of ratoon 'Chaling' CWR was studied under the stress of the natural low temperature in winter in Changsha, Hunan province, China, especially under the stress of abnormal natural low temperature in Changsha in 2008, taking other ratoon CWR accessions and ratoon cultivated rice phenotypes as control. RESULTS: The results showed that ratoon 'Chaling' CWR can safely overwinter under the natural conditions in Changsha (28° 22' N), Hunan province, China, which is a further and colder northern place than its habitat, even if it suffers a long-term low temperature stress with ice and snow. In 2008, an extremely cold winter appeared in Changsha, i.e., the average daily mean temperature of 22 consecutive days from January 13 to February 3 was - 1.0 °C, and the extreme low temperature was - 4.7 °C. After subjected to this long-term cold stress, the overwinter survival rate of ratoon 'Chaling' CWR was 100%, equals to that of ratoon 'Dongxiang' CWR which is northernmost distribution in the word among wild rice populations, higher than those of ratoon 'Fusui' CWR, ratoon 'Jiangyong' CWR, and ratoon 'Liujiang' CWR (63.55-83.5%) as well as those of ratoon 'Hainan' CWR, ratoon 'Hepu' CWR, and all the ratoon cultivated rice phenotypes including 3 japonica ones, 3 javanica ones, and 5 indica ones (0.0%). CONCLUSIONS: The results indicate that ratoon 'Chaling' CWR possesses strong cold tolerance and certain freezing tolerance.


Subject(s)
Oryza/physiology , Adaptation, Physiological/physiology , Cold Temperature , Cold-Shock Response/physiology , Phenotype , Seasons
3.
Mem. Inst. Oswaldo Cruz ; 115: e190413, 2020. tab, graf
Article in English | LILACS | ID: biblio-1101274

ABSTRACT

BACKGROUND The leishmaniases are complex neglected diseases caused by protozoan parasites of the genus Leishmania. Leishmania braziliensis is the main etiological agent of cutaneous leishmaniasis in the New World. In recent studies, genomic changes such as chromosome and gene copy number variations (CNVs), as well as transcriptomic changes have been highlighted as mechanisms used by Leishmania species to adapt to stress situations. OBJECTIVES The aim of this study was to determine the effect of short-term minor temperature shifts in the genomic and transcriptomic responses of L. braziliensis promastigotes in vitro. METHODS Growth curves, genome and transcriptome sequencing of L. braziliensis promastigotes were conducted from cultures exposed to three different temperatures (24ºC, 28ºC and 30ºC) compared with the control temperature (26ºC). FINDINGS Our results showed a decrease in L. braziliensis proliferation at 30ºC, with around 3% of the genes showing CNVs at each temperature, and transcriptomic changes in genes encoding amastin surface-like proteins, heat shock proteins and transport proteins, which may indicate a direct response to temperature stress. MAIN CONCLUSIONS This study provides evidence that L. braziliensis promastigotes exhibit a decrease in cell density, and noticeable changes in the transcriptomic profiles. However, there were not perceptible changes at chromosome CNVs and only ~3% of the genes changed their copies in each treatment.


Subject(s)
Animals , Temperature , Leishmania braziliensis/genetics , Adaptation, Physiological/genetics , DNA Copy Number Variations/genetics , Transcriptome/genetics , Adaptation, Physiological/physiology , Gene Expression Profiling , Genetic Profile
4.
Braz. j. med. biol. res ; 53(7): e8763, 2020. tab, graf
Article in English | LILACS, ColecionaSUS | ID: biblio-1132529

ABSTRACT

Upper limb performance is affected by diabetes mellitus (DM). Neuromuscular junction (NMJ) is a key structure to understand the relationship between performance and morphology in DM. The aim of the study was to analyze NMJ plasticity due to DM in an animal model and its relationship with the function of forelimbs in rats. Twelve Wistar rats were divided into control (C) and DM groups. Animals were trained to perform a grasping task, following procedures of habituation, shaping, and reaching task. DM was induced using streptozotocin. Forelimb neuromuscular performance for dexterity was evaluated one day before DM induction and five weeks following induction. After that, biceps, triceps, and finger flexors and extensors were removed. Connective tissue and muscle fiber cross-sectional area (CSA) were measured. NMJ was assessed by its morphometric characteristics (area, perimeter, and maximum diameter), using ImageJ software. Motor performance analyses were made using single pellet retrieval task performance test. Student's t-test was used for comparisons between groups. A significant decrease in all NMJ morphometric parameters was observed in the DM group compared with the C group. Results showed that DM generated NMJ retraction in muscles involved in a reaching task. These alterations are related to signs of muscular atrophy and to poor reaching task performance. In conclusion, induced DM caused NMJ retraction and muscular atrophy in muscles involved in reaching task performance. Induced DM caused significantly lower motor performance, especially in the final moments of evaluation, when DM compromised the tropism of the muscular tissue.


Subject(s)
Animals , Male , Rabbits , Rats , Task Performance and Analysis , Adaptation, Physiological/physiology , Diabetes Mellitus, Experimental/pathology , Neuromuscular Junction/pathology , Rats, Wistar , Diabetes Mellitus, Experimental/physiopathology , Neuromuscular Junction/physiopathology
5.
Braz. j. biol ; 78(4): 736-741, Nov. 2018. tab, graf
Article in English | LILACS | ID: biblio-951613

ABSTRACT

Abstract We analyzed floristic variations in fern's metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated from a redundancy analysis. We found 24 species belonging to 20 genera and 12 families. The fern's flora showed high floristic heterogeneity (>75% for most of the plot's associations). The fern's metacommunity was structured along an abiotic gradient modulated by temperature, luminosity, and relative soil moisture.


Resumo Analisamos as variações florísticas na metacomunidade de samambaias em escala local e sua relação com fatores abióticos em um remanescente de Floresta Atlântica no Nordeste do Brasil. Variações florísticas e ambientais foram acessadas a partir de dez parcelas de 10 × 20 m. Realizamos análises de cluster, baseado no índice de similaridade de Bray-Curtis para estabelecer relações florísticas. A influência de fatores abióticos: luminosidade, temperatura, umidade relativa do ar e umidade relativa do solo foram avaliadas a partir da análise de redundância. Encontramos 24 espécies pertencentes a 20 gêneros e 12 famílias. A flora de samambaias exibiu uma elevada heterogeneidade florística (>75% para a maioria das associações entre plots). Observou-se que a metacomunidade de samambaias estava estruturada ao longo de um gradiente abiótico modulado pela temperatura, luminosidade e umidade relativa do solo.


Subject(s)
Ferns/classification , Biodiversity , Environment , Brazil , Adaptation, Physiological/physiology , Cluster Analysis , Forests
6.
Braz. j. biol ; 78(4): 706-717, Nov. 2018. tab, graf
Article in English | LILACS | ID: biblio-951594

ABSTRACT

Abstract Vegetative aerial organs are considerably more exposed to environmental conditions and can reflect the specific adaptations of plants to their local environment. Aldama grandiflora species are known to be widely distributed in Brazil; therefore, individuals from different populations of this species are thought to be exposed to different abiotic and biotic conditions. Several anatomical studies conducted on Brazilian Aldama species have mainly focused on the qualitative anatomical characters or traits of these species, but not on their quantitative traits. In this study, we evaluated whether climate and soil conditions can change the morphometry among individuals of A. grandiflora collected from six sites in the Goiás State, Brazil, by assessing their anatomical characters. Further, soil sampling was performed, and climate data were collected from all the six sites. The analysis indicated few statistical differences among the populations evaluated, showing that A. grandiflora presented consistent leaf and stem anatomical characteristics. The small morpho-anatomical differences found among individuals of the different populations evaluated, reflected the soil conditions in which these populations were grown. Therefore, environmental factors have a significant influence on the morpho-anatomy of Aldama grandiflora.


Resumo Os órgãos vegetativos aéreos estão consideravelmente mais expostos às condições ambientais e podem refletir as adaptações específicas das plantas ao seu habitat. A espécie Aldama grandiflora é amplamente distribuída no Brasil e, dessa forma, indivíduos de diferentes populações podem estar expostos a diferentes condições ambientais. Vários estudos anatômicos realizados com espécies brasileiras do gênero Aldama têm abordado, principalmente, as características anatômicas qualitativas dessas espécies, mas não em suas características quantitativas. Neste estudo avaliamos se as condições climáticas e do solo podem alterar a morfometria entre os indivíduos de A. grandiflora coletados em seis populações do Estado de Goiás. Foram avaliados os caracteres anatômicos foliares e caulinares, além da amostragem do solo e coleta de dados climáticos, para os seis locais. A análise indicou algumas diferenças estatísticas entre as populações avaliadas, mostrando que A. grandiflora apresentou características anatômicas foliares e caulinares bastante consistentes. As pequenas diferenças morfo-anatômicas encontradas entre indivíduos das diferentes populações avaliadas, refletiram as condições do solo nos quais essas populações se desenvolveram. Assim sendo, fatores ambientais relacionados ao clima e condições do solo têm uma influência significativa sobre a morfo-anatomia de Aldama grandiflora.


Subject(s)
Soil , Adaptation, Physiological/physiology , Climate , Asteraceae/physiology , Brazil , Plant Stems/physiology , Plant Stems/ultrastructure , Plant Leaves/physiology , Plant Leaves/ultrastructure , Asteraceae/ultrastructure
7.
Braz. j. med. biol. res ; 51(6): e6602, 2018. tab, graf
Article in English | LILACS | ID: biblio-889101

ABSTRACT

The aim of this study was to investigate the reproductive, biochemical, and hematological outcomes of pregnant rats exposed to protein restriction. Wistar rat dams were fed a control normal-protein (NP, 17% protein, n=8) or a low-protein (LP, 8% protein, n=14) diet from the 1st to the 20th day of pregnancy. On the 20th day, the clinical signs of toxicity were evaluated. The pregnant rats were then anesthetized and blood samples were collected for biochemical-hematological analyses, and laparotomy was performed to evaluate reproductive parameters. No sign of toxicity, or differences (P>0.05) in body weight gain and biochemical parameters (urea, creatinine, albumin, globulin, and total protein) between NP and LP pregnant dams were observed. Similarly, hematological data, including red blood cell count, white blood cell count, hemoglobin, hematocrit, red blood cell distribution width (coefficient of variation), mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, % lymphocytes, absolute lymphocyte count, platelet count, and mean platelet volume were similar (P>0.05) at the end of pregnancy. Reproductive parameters (the dam-offspring relationship, ovary mass, placenta mass, number of corpora lutea, implantation index, resorption index, and the pre- and post-implantation loss rates) were also not different (P>0.05) between NP and LP pregnant dams. The present data showed that a protein-restricted diet during pregnancy did not alter reproductive, biochemical, and hematological parameters and seems not to have any toxic effect on pregnant Wistar rats.


Subject(s)
Animals , Male , Female , Pregnancy , Rats , Adaptation, Physiological/physiology , Diet, Protein-Restricted/methods , Fetal Development/physiology , Genitalia, Female/physiology , Urea/blood , Hemoglobins/analysis , Weight Gain/physiology , Proteins/analysis , Rats, Wistar , Creatinine/blood , Albumins/analysis , Erythrocyte Count , Globulins/analysis , Hematocrit , Leukocyte Count
8.
Biol. Res ; 51: 47, 2018. tab, graf
Article in English | LILACS | ID: biblio-983951

ABSTRACT

Increased levels of greenhouse gases in the atmosphere and associated climatic variability is primarily responsible for inducing heat waves, flooding and drought stress. Among these, water scarcity is a major limitation to crop productivity. Water stress can severely reduce crop yield and both the severity and duration of the stress are critical. Water availability is a key driver for sustainable cotton production and its limitations can adversely affect physiological and biochemical processes of plants, leading towards lint yield reduction. Adaptation of crop husbandry techniques suitable for cotton crop requires a sound understanding of environmental factors, influencing cotton lint yield and fiber quality. Various defense mechanisms e.g. maintenance of membrane stability, carbon fixation rate, hormone regulation, generation of antioxidants and induction of stress proteins have been found play a vital role in plant survival under moisture stress. Plant molecular breeding plays a functional role to ascertain superior genes for important traits and can offer breeder ready markers for developing ideotypes. This review highlights drought-induced damage to cotton plants at structural, physiological and molecular levels. It also discusses the opportunities for increasing drought tolerance in cotton either through modern gene editing technology like clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), zinc finger nuclease, molecular breeding as well as through crop management, such as use of appropriate fertilization, growth regulator application and soil amendments.


Subject(s)
Stress, Physiological/physiology , Adaptation, Physiological/physiology , Plants, Genetically Modified/physiology , Gene Expression Regulation, Plant/physiology , Gossypium/physiology , Droughts , Stress, Physiological/genetics , Adaptation, Physiological/genetics , Plants, Genetically Modified/genetics , Gene Expression Regulation, Plant/genetics , Gossypium/genetics , Acclimatization/genetics
9.
Clinics ; 73: e303, 2018. tab
Article in English | LILACS | ID: biblio-952785

ABSTRACT

OBJECTIVES: This study sought to analyze the extent of motor adaptation in ankle plantar flexors and dorsiflexors among older drivers during clinical isokinetic testing. METHODS: One hundred older adults (70.4±5.7 years) participated in two bilateral ankle plantar flexor and dorsiflexor isokinetic assessments at 30°/sec. Peak torque (PTQ), PTQ adjusted for body weight (PTQ/BW), and total work (TW) were analyzed. RESULTS: On the dominant side, PTQ/BW and TW were significantly greater for the second plantar flexion test than were those for the first such test (p<0.001), whereas PTQ, PTQ/BW, and TW (p<0.001) were significantly greater for the second dorsiflexion test than were those for the first such test. On the non-dominant side, plantar flexion PTQ and TW were significantly lower for the second test than were those for the first test (p<0.001). CONCLUSION: Older drivers demonstrated better performance with the dominant limb on the second test. The low variability in test execution showed the existence of a motor adaptation effect for the tested movements, despite the short recovery period between the assessments.


Subject(s)
Humans , Male , Female , Aged , Automobile Driving , Adaptation, Physiological/physiology , Ankle Joint/physiology , Motor Activity/physiology , Reference Values , Body Weight/physiology , Aging/physiology , Age Factors , Statistics, Nonparametric , Torque , Muscle Strength/physiology , Muscle Contraction/physiology
10.
An. acad. bras. ciênc ; 89(4): 3015-3029, Oct.-Dec. 2017. tab, graf
Article in English | LILACS | ID: biblio-886874

ABSTRACT

ABSTRACT Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.


Subject(s)
Photosynthesis/physiology , Ricinus/physiology , Stress, Physiological/physiology , Adaptation, Physiological/physiology , Water , Seasons , Tropical Climate , Plant Transpiration , Desert Climate , Droughts , Humidity
11.
Arq. bras. cardiol ; 108(4): 323-330, Apr. 2017. tab, graf
Article in English | LILACS | ID: biblio-838725

ABSTRACT

Abstract Background: Resistance and aerobic training are recommended as an adjunctive treatment for hypertension. However, the number of sessions required until the hypotensive effect of the exercise has stabilized has not been clearly established. Objective: To establish the adaptive kinetics of the blood pressure (BP) responses as a function of time and type of training in hypertensive patients. Methods: We recruited 69 patients with a mean age of 63.4 ± 2.1 years, randomized into one group of resistance training (n = 32) and another of aerobic training (n = 32). Anthropometric measurements were obtained, and one repetition maximum (1RM) testing was performed. BP was measured before each training session with a digital BP arm monitor. The 50 training sessions were categorized into quintiles. To compare the effect of BP reduction with both training methods, we used two-way analysis of covariance (ANCOVA) adjusted for the BP values obtained before the interventions. The differences between the moments were established by one-way analysis of variance (ANOVA). Results: The reductions in systolic (SBP) and diastolic BP (DBP) were 6.9 mmHg and 5.3 mmHg, respectively, with resistance training and 16.5 mmHg and 11.6 mmHg, respectively, with aerobic training. The kinetics of the hypotensive response of the SBP showed significant reductions until the 20th session in both groups. Stabilization of the DBP occurred in the 20th session of resistance training and in the 10th session of aerobic training. Conclusion: A total of 20 sessions of resistance or aerobic training are required to achieve the maximum benefits of BP reduction. The methods investigated yielded distinct adaptive kinetic patterns along the 50 sessions.


Resumo Fundamento: Os treinamentos de força e aeróbio são indicados para o tratamento adjuvante da hipertensão. Entretanto, o número de sessões necessárias até estabilização do efeito hipotensor com o exercício ainda não está claramente estabelecido. Objetivo: Estabelecer a cinética adaptativa das respostas tensionais em função do tempo e do tipo de treinamento em hipertensos. Métodos: Foram recrutados 69 hipertensos com idade média de 63,4 ± 2,1 anos, randomizados em um grupo de treinamento de força (n = 32) e outro de treinamento aeróbio (n = 32). Foram realizadas medidas antropométricas e testes de uma repetição máxima (1RM). A pressão arterial (PA) foi medida antes de cada sessão de treinamento com um aparelho de pressão digital de braço. As 50 sessões de treinamento foram categorizadas em quintis. Para comparar o efeito da redução da PA entre os métodos de treinamentos (between), utilizamos análise de covariância (ANCOVA) bifatorial ajustada para os valores de PA pré-intervenção. As diferenças entre os momentos foram estabelecidas por análise de variância (ANOVA) unifatorial. Resultados: As reduções na PA sistólica (PAS) e diastólica (PAD) foram de 6,9 mmHg e 5,3 mmHg, respectivamente, com o treinamento de força e 16,5 mmHg e 11,6 mmHg, respectivamente, com o treinamento aeróbio. A cinética hipotensiva da PAS apresentou reduções significativas até a 20ª sessão em ambos os grupos. Observou-se estabilização da PAD na 20ª sessão com o treinamento de força e na 10ª sessão com o aeróbio. Conclusão: São necessárias 20 sessões de treinamento de força ou aeróbio para alcance dos benefícios máximos de redução da PA. Os métodos investigados proporcionaram padrões cinéticos adaptativos distintos ao longo das 50 sessões.


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Exercise/physiology , Resistance Training , Post-Exercise Hypotension/physiopathology , Hypertension/physiopathology , Systole/physiology , Time Factors , Blood Pressure/physiology , Adaptation, Physiological/physiology , Kinetics , Analysis of Variance , Diastole/physiology
12.
Braz. j. biol ; 77(1): 52-59, Jan-Mar. 2017. tab, graf
Article in English | LILACS | ID: biblio-839168

ABSTRACT

Abstract Some macrophytes species show a high growth potential, colonizing large areas on aquatic environments. Cattail (Typha angustifolia L.) uncontrolled growth causes several problems to human activities and local biodiversity, but this also may lead to competition and further problems for this species itself. Thus, the objective of this study was to investigate anatomical modifications on T. angustifolia plants from different population densities, once it can help to understand its biology. Roots and leaves were collected from natural populations growing under high and low densities. These plant materials were fixed and submitted to usual plant microtechnique procedures. Slides were observed and photographed under light microscopy and images were analyzed in the UTHSCSA-Imagetool software. The experimental design was completely randomized with two treatments and ten replicates, data were submitted to one-way ANOVA and Scott-Knott test at p<0.05. Leaves from low density populations showed higher stomatal density and index. These modifications on stomatal characteristics were more evident on the leaf abaxial surface. Plants from low density populations showed thicker mesophyll and higher proportion of aerenchymal area. Roots from low density populations showed a higher proportion of the vascular cylinder. Whereas, plants from higher density populations showed greater thickness of the endodermis, exodermis, phloem and root cortex. Higher density populations showed a higher proportion of aerenchymal gaps in the root cortex. Therefore, cattail plants from populations growing under high density population show anatomical traits typical of plants under stress, which promotes the development of less functional anatomical modifications to aquatic environments.


Resumo Algumas espécies de macrófitas podem apresentar um elevado potencial de crescimento, colonizando extensas áreas de ambientes aquáticos. O crescimento descontrolado da taboa (Typha angustifolia L.) causa problemas para a biodiversidade local e para atividades antrópicas, isso também pode levar à competição e problemas para a própria espécie. Dessa forma, o objetivo desse trabalho foi verificar se ocorrem modificações anatômicas em plantas de Typha angustifolia L. de diferentes densidades populacionais, uma vez que essas podem auxiliar na compreensão da biologia dessa espécie. Raízes e folhas de T. angustifolia foram coletadas de populações naturais com alto e baixo adensamento populacional. Esse material vegetal foi fixado e submetido a procedimentos usuais de microtécnica vegetal. As lâminas foram observadas e fotografadas em microscopia de luz e as imagens analisadas no software UTHSCSA-Imagetool. O delineamento experimental foi inteiramente casualizado com dois tratamentos e dez repetições, os dados foram submetidos à análise de variância e ao teste de Scott-Knott para p<0,05. As folhas das populações com baixa densidade demonstraram maior densidade e índice estomáticos. Essas características foram mais evidentes na superfície abaxial em comparação com a superfície adaxial. As plantas de populações com baixo adensamento demonstraram maior espessura do mesofilo e área de aerênquima foliar. As raízes das populações com baixo adensamento demonstraram maior proporção do cilindro vascular. Por outro lado, as plantas de populações com alto adensamento demonstraram maior espessura da endoderme, exoderme, floema e do córtex nas raízes. Populações de alto adensamento demonstraram maior proporção de aerênquima no córtex radicular. Portanto, plantas de taboa sob alto adensamento populacional estão sob estresse o qual promove o desenvolvimento de modificações anatômicas menos funcionais para os ambientes aquáticos.


Subject(s)
Stress, Physiological/physiology , Typhaceae/anatomy & histology , Adaptation, Physiological/physiology , Random Allocation , Analysis of Variance , Population Density , Plant Roots/anatomy & histology , Plant Leaves/growth & development , Typhaceae/physiology , Biodiversity , Aquatic Organisms/physiology
13.
Braz. j. biol ; 77(1): 191-198, Jan-Mar. 2017. tab, graf
Article in English | LILACS | ID: biblio-839154

ABSTRACT

Abstract Successful animal rearing under laboratory conditions for commercial processes or laboratory experiments is a complex chain that includes several stressors (e.g., sampling and transport) and incurs, as a consequence, the reduction of natural animal conditions, economic losses and inconsistent and unreliable biological results. Since the invasion of the bivalve Limnoperna fortunei (Dunker, 1857) in South America, several studies have been performed to help control and manage this fouling pest in industrial plants that use raw water. Relatively little attention has been given to the laboratory rearing procedure of L. fortunei, its condition when exposed to a stressor or its acclimation into laboratory conditions. Considering this issue, the aims of this study are to (i) investigate L. fortunei physiological responses when submitted to the depuration process and subsequent air transport (without water/dry condition) at two temperatures, based on glycogen concentrations, and (ii) monitor the glycogen concentrations in different groups when maintained for 28 days under laboratory conditions. Based on the obtained results, depuration did not affect either of the groups when they were submitted to approximately eight hours of transport. The variation in glycogen concentration among the specimens that were obtained from the field under depurated and non-depurated conditions was significant only in the first week of laboratory growth for the non-depurated group and in the second week for the depurated group. In addition, the tested temperature did not affect either of the groups that were submitted to transport. The glycogen concentrations were similar to those of the specimens that were obtained from the field in third week, which suggests that the specimens acclimated to laboratory conditions during this period of time. Thus, the results indicate that the air transport and acclimation time can be successfully incorporated into experimental studies of L. fortunei. Finally, the tolerance of L. fortunei specimens to the stressor tested herein can help us understand the invasive capacity of this mussel during the establishment process.


Resumo A criação bem sucedida de animais em condições de laboratório para processos comerciais ou experimentais é uma cadeia complexa que inclui vários fatores de estresse (ex. coleta e transporte) que tem como consequência a redução das condições naturais do animal, prejuízos econômicos e resultados biológicos inconsistentes. Desde a invasão do bivalve Limnoperna fortunei (Dunker, 1857) na América do Sul, vários estudos têm sido realizados para ajudar no controle e gestão dessa praga em plantas industriais que utilizam água. Relativamente pouca atenção tem sido dada ao processo de criação de L. fortunei em laboratório, sua condição quando exposta ao estresse e sua aclimatação a condições de laboratório. Considerando estes aspectos, os objetivos deste estudo foram: (i) investigar as respostas fisiológicas de L. fortunei submetidos ao processo de depuração e subsequente transporte (sem água/condição seca) em duas temperaturas, analisando as diferentes concentrações de glicogênio e (ii) monitorar as concentrações de glicogênio nos diferentes grupos, quando mantidos por 28 dias em condições de laboratório. Com base nos resultados obtidos, a depuração não afetou nenhum grupo quando eles foram submetidos a oito horas de transporte. A variação da concentração de glicogênio entre os espécimes do campo quando depurados e não depurados, foi significativa apenas em relação à primeira semana em laboratório para o grupo não depurado e à segunda semana para o grupo depurado. Além disto, a temperatura testada não afetou os grupos submetidos ao transporte. As concentrações de glicogénio foram semelhantes as dos espécimes do campo a partir da terceira semana, o que sugere que os espécimes estão aclimatados às condições de laboratoriais neste período de tempo. Assim, os resultados indicam que o transporte ao ar e o tempo de aclimatação podem ser incorporados com sucesso aos estudos experimentais com L. fortunei. Finalmente, o conhecimento sobre a tolerância de L. fortunei ao estresse pode ajudar a entender a capacidade invasiva deste durante o processo de estabelecimento.


Subject(s)
Animals , Adaptation, Physiological/physiology , Mytilidae/physiology , South America , Specimen Handling , Temperature , Water , Analysis of Variance , Mytilidae/chemistry , Glycogen/analysis , Acclimatization/physiology
14.
Motriz (Online) ; 23(spe): e101611, 2017. graf
Article in English | LILACS | ID: biblio-841859

ABSTRACT

Abstract AIMS Previously, we verified that overtrained mice upregulated the TRB3 levels, its association with Akt, and the hepatic concentrations of glycogen. It is known that APPL1 can limit the interaction between TRB3 and Akt, playing an important role in the glucose homeostasis. Thus, we verified the effects of three overtraining protocols on the hepatic levels of APPL1 and APPL2. METHODS Rodents were divided into control (CT), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up) and overtrained by running without inclination (OTR). The hepatic contents of APPL1 and APPl2 were measured by the immunoblotting technique. RESULTS Significant elevation of APPL1 observed in the OTR/down and OTR/up groups, as well as the tendency of increase (p=0.071) observed in the OTR group. CONCLUSION These results indicate that this particular protein is likely to participate in the glucose homeostasis previously observed in response to these OT protocols.(AU)


Subject(s)
Animals , Male , Mice , Adaptation, Physiological/physiology , Adaptor Proteins, Signal Transducing/metabolism , Hemostasis/physiology , Insulin/metabolism , Liver/physiology , Resistance Training , Mice, Inbred C57BL
15.
Braz. j. biol ; 76(3): 577-582, tab, graf
Article in English | LILACS | ID: lil-785029

ABSTRACT

Abstract This research evaluated the effect of flooding on the microphytobenthos community structure in a microbial mat from a tropical salt flat. Field samples were collected during four consecutive days: on the first three days the salt flat was dry, on the fourth day it was flooded by rain. In order to evaluate the community maintained in flood conditions, samples from this area were collected and kept in the laboratory for 10 days with sea water. The results of total abundance of microphytobenthos varied from 4.2 × 108 to 2.9 × 109 organisms L–1, total density increased one order of magnitude under the effect of water for both situations of precipitation in the salt flat and in experimental conditions, an increase due to the high abundance of Microcoleus spp. Shannon index (H’) was higher during the desiccation period. Our data suggest that changes in the abundance of organisms were due to the effect of water. The dominance of the most abundant taxa remained the same under conditions of desiccation and influence of water, and there is probably a consortium of microorganisms in the microbial mat that helps to maintain these dominances.


Resumo Esse trabalho avaliou os efeitos da inundação na estrutura da comunidade microfitobentônica de um tapete microbiano em uma planície hipersalina tropical. As amostragens foram realizadas no campo durante quatro dias consecutivos: nos três primeiros dias o local estava seco e no quarto dia foi inundando com chuva. Para avaliar a comunidade mantida em condições de inundação, foram coletadas amostras dessa região, sendo mantidas em laboratório por 10 dias com água do mar. Os resultados mostraram que a abundância total do microfitobentos variou de 4.2 × 108 a 2.9 × 109 organismos L–1, a densidade aumentou em uma ordem de grandeza com a influência da água, tanto na planície hipersalina como nas condições experimentais, um aumento que foi devido às maiores abundâncias de Microcoleus spp. O índice de Shannon (H’) foi mais elevado durante o período de dessecação. Nossos dados sugerem que as mudanças na abundância dos organismos foram devidas ao efeito da água, a dominância dos táxons mais abundantes permaneceu a mesma durante as condições de dessecação e inundação, e possivelmente existe um consórcio entre os microrganismos do tapete microbiano no qual eles ajudam a manter essa dominância.


Subject(s)
Tropical Climate , Adaptation, Physiological/physiology , Environmental Monitoring/methods , Geologic Sediments , Floods , Microalgae/physiology , Rain , Seawater , Water , Sodium Chloride , Cyanobacteria
16.
Braz. j. biol ; 76(3): 743-749, tab, graf
Article in English | LILACS | ID: lil-785025

ABSTRACT

Abstract Many aspects of sex change in reef fishes have been studied, including behavior and social organization. However, gonad histology remains the most robust way to identify sexual patterns in fishes. Some uncommon tissues remain poorly described, such as the accessory gonadal structures found in species from the Gobiidae family, which are rare in other bony fishes. This is the first report of the testicular gland in Gramma brasiliensis and for the Grammatidae family. Between April 2011 and February 2012 eighty specimens were collected during four dive campaigns on the Taipus de Fora reef (13°56’20”S 38°55’32”W), Bahia, Northeast Brazil, and their sex was determined. Thirteen per cent of the active-females and 90% of the active-males had testicular gland tissue in their ovotestis. This discovery led to additional research into the characteristics of the gland tissue and its relationship with gonadal maturation. Three patterns of testicular gland development were found in Brazilian basslet ovotestis. Both ova and sperm-producing gonad contained testicular gland tissue, and the appearance of this tissue seems to be the first modification of ovotestis tissue marking the beginning of the protogynous sex-change process in G. brasiliensis.


Resumo Diversos aspectos da troca de sexo em peixes recifais vem sendo estudados, incluindo comportamentos e organização social. Entretanto, a histologia das gônadas continua sendo a maneira mais robusta para se identificar padrões sexuais em peixes. Alguns tecidos incomuns, tais como as estruturas anexas a gônada encontradas em espécies da família Gobiidae e raras em outras espécies são pouco estudados. Este trabalho é a primeira descrição da glândula testicular em Gramma brasiliensis e para a família Grammatidae. Entre abril de 2011 e fevereiro de 2012, oitenta espécimes foram coletados durante quatro amostragens no recife de Taipus de Fora (13°56’20”S 38°55’32”W), Bahia, Brasil, e tiveram seus sexos determinados. Treze por cento das fêmeas ativas e noventa por cento dos machos ativos apresentaram tecido da glândula testicular em suas gônadas. Esta descoberta levou ao estudo da características dessa estrutura e sua relação com a maturação gonadal. Foram identificados três padrões de desenvolvimento da glândula testicular nas gônadas do Gramma brasiliensis. Tanto as gônadas produtoras de espermatozoides quanto as de oócitos apresentaram tecido da glândula testicular, e o surgimento desse tecido parece ser a primeira modificação gonadal do início da troca de sexo protogínica em G. brasiliensis.


Subject(s)
Animals , Male , Female , Testis/physiology , Perciformes/physiology , Adaptation, Physiological/physiology , Hermaphroditic Organisms/physiology , Brazil , Gonads/physiology
17.
Rev. biol. trop ; 64(2): 507-520, abr.-jun. 2016. tab, ilus
Article in English | LILACS | ID: biblio-843294

ABSTRACT

AbstractPlants have limited resources to invest in reproduction, vegetative growth and defense against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. In this study, we evaluated the trade-off effect between years of high and low fruiting on the investment of resources for growth and defense, and their indirect effects on herbivory in Copaifera langsdorffii. Our questions were: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by the Carbon/Nutrient Balance hypothesis (CNBH), resulting in more availability of resources to be allocated for defense?, (ii) does the variation in resource allocation for growth and defense between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a Cerrado area were monitored during 2008 (year of high fruiting) and 2009 (year of no fruiting) to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defense (tannin concentration and plant hypersensitivity) and herbivory (galling attack and folivory). According to our first question, we observed that in the fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources that could be invested both in growth as in defense. In the same way, we observed an inter-annual variation in herbivorous attack, and found that plants with higher leaf biomass and tannin concentration, experienced higher galling attack and hypersensitive reaction, regardless years. These findings suggested that plants’ resistance to herbivory is a good proxy of plant defense and an effective defense strategy for C. langsdorffii, besides the evidence of indirect responses of the third trophic level, as postulated by the second question. In summary, the supra-annual fruiting pattern promoted several changes on plant development, demonstrating the importance of evaluating different plant traits when characterizing the vegetative investment. As expected by theory, the trade-off in resource allocation favored changes in defense compounds production and patterns of herbivory. The understanding of this important element of insect-plant interactions will be fundamental to decipher coevolutionary life histories and interactions between plant species reproduction and herbivory. Besides that, only through long-term studies we will be able to build models and develop more accurate forecasts about the factors that trigger the bottom-up effect on herbivory performance, as well the top-down effect of herbivores on plant trait evolution. Rev. Biol. Trop. 64 (2): 507-520. Epub 2016 June 01.


ResumenLas plantas tienen recursos limitados para invertir en reproducción, crecimiento vegetativo y defensa contra herbívoros. El cambio en la distribución de recursos promueve variaciones en rasgos vegetales, que pueden afectar los niveles tróficos superiores. Durante dos años consecutivos de alta y baja inversión reproductiva se evaluó el cambio de recursos entre crecimiento vegetativo y defensa, y su efecto indirecto sobre la herbivoría en Copaifera langsdorffii. Nos preguntamos: i) ¿La inversión de recursos para la reproducción causa reducción del crecimiento vegetativo, como predice la hipótesis de equilibrio carbono/nutrientes, haciendo posible gastar más recursos en defensa? ii) ¿La variación en distribución de recursos para crecimiento y defensa entre años de alta y baja fructificación modifica indirectamente la herbivoría? Se monitorearon treinta y cinco árboles durante 2008 (gran fructificación) y 2009 (sin fructificación) en un área de vegetación de cerrado (Brasil), para evaluar la inversión diferencial en rasgos vegetativos (biomasa, crecimiento y No. de ramificaciones), defensa (concentración de taninos e hipersensibilidad vegetal) y herbivoría. De acuerdo a nuestra primera pregunta, se observó que en el año de fructificación la biomasa leñosa afectó negativamente la concentración de taninos, indicando que la producción de frutos redujo los recursos que podían invertirse en crecimiento y defensa. Además, la resistencia de las plantas y el ataque de agallas fueron influidos positivamente por la concentración de taninos y la biomasa foliar, lo que sugiere que la resistencia de los árboles a la herbivoría es un buen indicador de defensa vegetal y una estrategia efectiva de defensa de C. langsdorffii, además hay evidencia de respuesta trófica indirecta, como se postula en la segunda pregunta. En resumen, el patrón de fructificación supra-anual provoca varios efectos en el desarrollo de las plantas, mostrando la importancia de evaluar diversos rasgos vegetales al caracterizar la inversión de recursos de una especie. Como se esperaba, el cambio en la distribución de recursos modifica la producción de compuestos de defensa y los patrones de herbivoría. El entendimiento de este elemento importante de las interacciones insecto-planta será fundamental para descifrar la historia natural coevolutiva y las interacciones entre reproducción vegetal y ataque herbívoro. Además de eso, solo a través de estudios a largo plazo vamos a ser capaces de construir modelos y desarrollar pronósticos más precisos acerca de los factores que desencadenan el efecto de abajo hacia arriba en el rendimiento de la herbivoría, así el efecto de arriba hacia abajo de los herbívoros sobre la evolución de las plantas.


Subject(s)
Animals , Adaptation, Physiological/physiology , Herbivory/physiology , Insecta/physiology , Fabaceae/physiology , Plant Tumors , Herbivory/classification , Insecta/classification , Fabaceae/growth & development , Fabaceae/parasitology
18.
Braz. j. microbiol ; 46(3): 835-840, July-Sept. 2015. tab
Article in English | LILACS | ID: lil-755815

ABSTRACT

Enterotoxigenic Staphylococcus aureus strains that were isolated from foods were investigated for their ability to develop direct-tolerance and cross-tolerance to sodium chloride (NaCl), potassium chloride (KCl), lactic acid (LA) and acetic acid (AA) after habituation in sublethal amounts (1/2 of the minimum inhibitory concentration - 1/2 MIC and 1/4 of the minimum inhibitory concentration - 1/4 MIC) of Origanum vulgare L. essential oil (OVEO). The habituation of S. aureus to 1/2 MIC and 1/4 MIC of OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by modulation of MIC values. Otherwise, exposing the strains to OVEO at sublethal concentrations maintained or increased the sensitivity of the cells to the tested stressing agents because the MIC values of OVEO, NaCl, KCl, LA and AA against the cells that were previously habituated to OVEO remained the same or decreased when compared with non-habituated cells. These data indicate that OVEO does not have an inductive effect on the acquisition of direct-tolerance or cross-tolerance in the tested enterotoxigenic strains of S. aureus to antimicrobial agents that are typically used in food preservation.

.


Subject(s)
Adaptation, Physiological/physiology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial/physiology , Oils, Volatile/pharmacology , Origanum/metabolism , Staphylococcal Food Poisoning/prevention & control , Staphylococcus aureus/metabolism , Acetic Acid/pharmacology , Enterotoxins/metabolism , Food Microbiology , Lactic Acid/pharmacology , Microbial Sensitivity Tests , Potassium Chloride/pharmacology , Rosmarinus/metabolism , Sodium Chloride/pharmacology , Staphylococcal Food Poisoning/microbiology , Staphylococcus aureus/pathogenicity
19.
Braz. j. microbiol ; 46(3): 683-690, July-Sept. 2015. tab, ilus
Article in English | LILACS | ID: lil-755831

ABSTRACT

An extracellular β-agarase was purified from Pseudoalteromonas sp. NJ21, a Psychrophilic agar-degrading bacterium isolated from Antarctic Prydz Bay sediments. The purified agarase (Aga21) revealed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular weight of 80 kDa. The optimum pH and temperature of the agarase were 8.0 and 30 °C, respectively. However, it maintained as much as 85% of the maximum activities at 10 °C. Significant activation of the agarase was observed in the presence of Mg2+, Mn2+, K+; Ca2+, Na+, Ba2+, Zn2+, Cu2+, Co2+, Fe2+, Sr2+ and EDTA inhibited the enzyme activity. The enzymatic hydrolyzed product of agar was characterized as neoagarobiose. Furthermore, this work is the first evidence of cold-adapted agarase in Antarctic psychrophilic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine, food and cosmetic industries.

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Subject(s)
Adaptation, Physiological/physiology , Agar/metabolism , Glycoside Hydrolases/metabolism , Pseudoalteromonas/enzymology , Antarctic Regions , Adaptation, Physiological/genetics , Bacterial Proteins/metabolism , Cold Temperature , Disaccharides/biosynthesis , Geologic Sediments/microbiology , Glycoside Hydrolases/isolation & purification , Hydrolysis , /genetics
20.
Braz. j. biol ; 75(2): 372-379, 05/2015. tab, graf
Article in English | LILACS | ID: lil-749689

ABSTRACT

Probably as a function of their wide geographical distribution, the different population of Macrobrachium amazonicum shrimp may present distinct physiological, biochemical, reproductive, behavioral, and ecological patterns. These differences are so accentuated that the existence of allopatric speciation has been suggested, although initial studies indicate that the genetic variability of populations happen at an intraspecific level. Among the biological responses described for M. amazonicum populations, those regarding osmoregulation and metabolism play a key role for being related to the occupation of diverse habitats. To this effect, we investigated osmoregulation through the role of free amino acids in cell volume control and metabolism, through oxygen consumption in larvae (zoeae I, II, V and IX) and/or post-larvae of a M. amazonicum population from Amazon, kept in aquaculture fish hatcheries in the state of São Paulo. The results add information regarding the existence of distinct physiological responses among M. amazonicum populations and suggest that possible adjustments to metabolism and to the use of free amino acids as osmolytes of the regulation of the larvae and post-larvae cell volume depend on the appearance of structures responsible for hemolymph osmoregulation like, for example, the gills. In this respect, we verified that zoeae I do not alter their metabolism due to the exposition to fresh or brackish water, but they reduce intracellular concentration of free amino acids when exposed to fresh water, what may suggest the inexistence or inefficient performance of the structures responsible for volume regulation and hemolymph composition. On the other hand, in zoeae II and V exposed to fresh and brackish water, metabolism alterations were not followed by changes in free amino acids concentration. Thus it is possible, as the structures responsible for osmoregulation and ionic regulation become functional, that the role of free amino acids gets diminished and oxygen consumption elevated, probably due to greater energy expenditure with the active transportation of salts through epithelial membranes. Osmotic challenges also seem to alter throughout development, given that in zoeae II oxygen consumption is elevated on brackish water of 18, but in zoeae V it happens in fresh water. After M. amazonicum metamorphosis, free amino acids begin to play an important role as intracellular osmolytes, because we verified an increase of up to 40% in post-larvae exposed to brackish water of 18. The main free amino acids involved in cell volume regulation of ontogenetic stages evaluated were the non essential ones: glutamic acid, glycine, alanine, arginine, and proline. Interestingly, larvae from estuarine population studied here survived until the zoeae V stage in fresh water, but in some populations far from the sea, zoeae die right after eclosion in fresh water or they do not reach zoeae III stage. In addition, given that in favorable conditions caridean shrimp larvae shorten their development, we may infer that the cultivation environment, in which larvae developed in the present work, was appropriate, because almost all zoeae VIII kept on brackish water underwent metamorphosis directly to post-larvae and did not go through zoeae IX stage.


Provavelmente como função da sua ampla distribuição geográfica, as diferentes populações do camarão Macrobrachium amazonicum podem apresentar distintos padrões fisiológicos, bioquímicos, reprodutivos, comportamentais e ecológicos. Essas diferenças são tão acentuadas que tem sido sugerido a existência de especiação alopátrica embora estudos iniciais indiquem que a variabilidade genética das populações ocorre ao nível intraespecífico. Dentre as respostas biológicas descritas para as populações de M. amazonicum, aquelas relacionadas à osmorregulação e metabolismo têm papel central por estarem relacionadas à ocupação dos diversos habitats. Nesse sentido, investigou-se a osmorregulação, por meio do papel dos aminoácidos livres no controle do volume celular e o metabolismo, por meio do consumo de oxigênio, em larvas (zoeas I, II, V e IX) e/ou pós-larvas de uma população de M. amazonicum oriunda da Amazônia e mantida em viveiros de aquicultura no estado de São Paulo. Os resultados adicionam informações a respeito da existência de respostas fisiológicas distintas entre as populações de M. amazonicum e sugerem que possíveis ajustes no metabolismo e no uso de aminoácidos livres como osmólitos da regulação do volume celular das larvas e pós-larvas dependem do surgimento de estruturas responsáveis pela osmorregulação da hemolinfa como, por exemplo, as brânquias. Nesse sentido, verificou-se que as zoeas I não alteram seu metabolismo em função da exposição à água doce ou salobra, mas reduzem a concentração intracelular de aminoácidos livres quando expostas à água doce, o que pode sugerir a inexistência ou um desempenho ineficiente das estruturas responsáveis pela regulação do volume e composição da hemolinfa. Por outro lado, nas zoeas II e V expostas à água doce ou salobra alterações no metabolismo não foram acompanhadas por mudanças na concentração dos aminoácidos livres. Assim é possível que à medida que estruturas responsáveis pela osmo e ionorregulação tornam-se funcionais, o papel dos aminoácidos livres se torne reduzido e o consumo de oxigênio elevado, provavelmente em função do maior gasto energético com o transporte ativo de sais através das membranas epiteliais. Os desafios osmóticos também parecem se alterar ao longo do desenvolvimento visto que em zoeas II o consumo de oxigênio é elevado em água salobra de 18 mas em zoeas V essa resposta ocorre em água doce. Após a metamorfose de M. amazonicum, os aminoácidos livres passam a ter papel importante como osmólitos intracelulares, pois se verificou um aumento de até 40% nas pós-larvas expostas à água salobra de 18. Os principais aminoácidos livres envolvidos na regulação do volume celular dos estágios ontogenéticos avaliados foram os não essenciais ácido glutâmico, glicina, alanina, arginina e prolina. Interessantemente, as larvas da população estuarina aqui estudada sobrevivem até o estágio de zoea V em água doce mas em algumas populações distantes do mar as zoeas morrem logo após a eclosão em água doce ou não chegam ao estágio de zoea III. Adicionalmente, visto que em condições favoráveis as larvas de camarões carídeos abreviam o seu desenvolvimento pode ser inferido que o meio de cultivo em que as larvas se desenvolveram no presente trabalho foi adequado, pois quase todas as zoeas VIII mantidas em água salobra sofreram diretamente a metamorfose para pós-larvas e não passaram pelo estágio de zoeas IX.


Subject(s)
Animals , Adaptation, Physiological/physiology , Fresh Water , Larva/metabolism , Osmoregulation/physiology , Palaemonidae/metabolism , Salinity , Larva/growth & development , Larva/physiology , Palaemonidae/growth & development , Palaemonidae/physiology
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