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1.
Trop Anim Health Prod ; 56(5): 189, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38864934

RESUMEN

The aim was to evaluate the quality of the sheep skin of different sex classes submitted to different levels of feed restriction. Sheep without defined racial pattern of different sex classes (15 non-castrated males, 15 castrated males and 15 females), with initial body weight of 18.1 ± 0.4 kg and mean age of 90 days were distributed in a factorial 3 × 3, with three sex classes and 3 levels of feed restriction (ad libitum intake and restricted intake at 70 and 80%), with 5 repetitions. After slaughter, the skins were collected for physical-mechanical tests. The effect of the sex classes x levels of dietary restriction interaction was observed for transverse thickness and longitudinal rupture elongation (p < 0.05). Animals fed ad libitum had greater longitudinal transverse thickness (p < 0.05). Animals fed ad libitum and 70% feed restriction showed greater transverse elongation at break (p < 0.05). As for the difference between sex classes in the transverse thickness variable for tearing strength, the interaction sex classes x levels of feed restriction for transverse thickness, longitudinal thickness, transverse tearing strength and longitudinal tearing strength occurred (p < 0.05). Feed restriction reduces the physical quality of the skin of sheep of different sex classes, and the use of castrated male sheep in positive energy balance is recommended to obtain leather with greater thickness, longitudinal rupture elongation and transverse tear strength.


Asunto(s)
Piel , Animales , Masculino , Femenino , Oveja Doméstica/fisiología , Oveja Doméstica/crecimiento & desarrollo , Factores Sexuales , Privación de Alimentos/fisiología , Alimentación Animal/análisis , Ovinos/fisiología , Ovinos/crecimiento & desarrollo , Orquiectomía/veterinaria
2.
Molecules ; 29(2)2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38276611

RESUMEN

The tanning industry generates effluents with high chromium content, which require treatment prior to discharge into the sewage system. This article explores the use of magnetic magnetite nanoparticles (MNPs) to remove Cr(VI) from aqueous solutions, such as tanning effluents. The MNPs were synthesized by coprecipitation reaction using the Olea europaea extract as a reducing agent. Subsequently, they were characterized by dynamic light scattering spectroscopy (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). MNPs with irregular morphology and diameters ranging from 73.28 to 162.90 nm were obtained. Cr(VI) removal was performed using jar test methodology, and its efficiency was evaluated in the laboratory for different initial Cr(VI) (mg/L) concentration and nanoparticle (g/L) concentration. A kinetic study was developed and indicated that the equilibrium adsorption mechanism corresponds to a pseudo-second-order model. Furthermore, the isotherm analysis revealed that chromium adsorption best fits the Langmuir isotherm. Finally, Cr(VI) removal rates from 85% to 100% were achieved in tanning and retanning effluents.


Asunto(s)
Nanopartículas de Magnetita , Olea , Contaminantes Químicos del Agua , Purificación del Agua , Nanopartículas de Magnetita/química , Cromo/química , Adsorción , Cinética , Contaminantes Químicos del Agua/química , Concentración de Iones de Hidrógeno , Purificación del Agua/métodos
3.
Trop Anim Health Prod ; 54(5): 314, 2022 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-36136133

RESUMEN

The aim was to evaluate the effect of residual feed intake (RFI) on the histological, physical and mechanical characteristics of the sheep skin confined in full sun or shade. Dorper sheep (n = 64), male, with an initial bodyweight of 17.8 ± 2.43 kg was confined for 40 days to determine the RFI. After classification, 30 animals with positive RFI and 30 animals with negative RFI were selected, which were distributed in 2 confinement environments. This was a factorial arrangement of 2 (groups of animals-positive RFI and negative RFI) × 2 (environments-full sun and shade), with 15 animals for each combination of factors. The sheep remained in confinement for 60 days. After slaughter, skins were divided in half, and fragments were collected from the right portion for histological sections. The left part of each skin was subjected to tanning. Interaction effect RFI × environment was found in the evaluation of leather fragments in the horizontal direction on elongation at break, leather thickness and tear strength (p < 0.05). An isolated effect of the environment was found on elongation at break of leather fragments in the evaluation on the vertical direction (p = 0.01) and on the number of secondary follicles during the histological evaluation of the dorsal and lateral regions of the skin (p < 0.05). An effect of the interaction RFI × environment was observed for the thermostatic layer of the hip region (p = 0.03). Sheep with positive RFI and kept in confinement in full sun have a leather with greater elongation at break and tear strength, important aspects in determining the quality of the product by the leather industry.


Asunto(s)
Ingestión de Alimentos , Piel , Alimentación Animal/análisis , Animales , Peso Corporal , Dieta/veterinaria , Conducta Alimentaria , Masculino , Ovinos
4.
Genes (Basel) ; 13(5)2022 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-35627282

RESUMEN

Skin cancer incidence has been increasing worldwide, representing a particularly high burden for populations of European ancestry. Outdoor and indoor tanning using ultraviolet (UV) radiation devices are major risk factors for skin cancer. While tanning behaviours can be modified by targeted interventions to reduce skin cancer rates, there is insufficient evidence on the motivations for tanning preferences and their relationship with pigmentation phenotypes. The present observational and genetically-informed study investigates motives for tanning and the role that pigmentation phenotypes play on outdoor and indoor tanning behaviour in British young adults. This study included 3722 participants from the Avon Longitudinal Study of Parents and Children in South West England, with data on pigmentation features, tanning ability and preferences, and SNP genotypes. Liking to tan and outdoor tanning were strongly influenced by pigmentary traits and tanning ability. However, the association of these phenotypes with UV indoor tanning was weaker. Our results provide evidence to support the implementation of skin cancer preventative interventions that consider individual biological characteristics and motives for undergoing outdoor and indoor tanning.


Asunto(s)
Neoplasias Cutáneas , Baño de Sol , Humanos , Estudios Longitudinales , Fenotipo , Pigmentación , Neoplasias Cutáneas/etiología , Neoplasias Cutáneas/genética , Adulto Joven
5.
Front Physiol ; 11: 591569, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33329040

RESUMEN

The cotton boll weevil, Anthonomus grandis, is the most economically important pest of cotton in Brazil. Pest management programs focused on A. grandis are based mostly on the use of chemical insecticides, which may cause serious ecological impacts. Furthermore, A. grandis has developed resistance to some insecticides after their long-term use. Therefore, alternative control approaches that are more sustainable and have reduced environmental impacts are highly desirable to protect cotton crops from this destructive pest. RNA interference (RNAi) is a valuable reverse genetics tool for the investigation of gene function and has been explored for the development of strategies to control agricultural insect pests. This study aimed to evaluate the biological role of the Laccase2 (AgraLac2) gene in A. grandis and its potential as an RNAi target for the control of this insect pest. We found that AgraLac2 is expressed throughout the development of A. grandis with significantly higher expression in pupal and adult developmental stages. In addition, the immunolocalization of the AgraLac2 protein in third-instar larvae using specific antibodies revealed that AgraLac2 is distributed throughout the epithelial tissue, the cuticle and the tracheal system. We also verified that the knockdown of AgraLac2 in A. grandis resulted in an altered cuticle tanning process, molting defects and arrested development. Remarkably, insects injected with dsAgraLac2 exhibited defects in cuticle hardening and pigmentation. As a consequence, the development of dsAgraLac2-treated insects was compromised, and in cases of severe phenotypic defects, the insects subsequently died. On the contrary, insects subjected to control treatments did not show any visible phenotypic defects in cuticle formation and successfully molted to the pupal and adult stages. Taken together, our data indicate that AgraLac2 is involved in the cuticle tanning process in A. grandis and may be a promising target for the development of RNAi-based technologies.

6.
J Environ Manage ; 269: 110787, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32430280

RESUMEN

The leather industry uses a large amount of chemicals to transform a raw hide into finished leather. Chemicals are not fully taken up by leather and thus end up in tannery wastewater. Physicochemical and toxicological characterization of tannery effluents has been widely assessed. However, the characterization of processing chemicals and their relation to the pollution load of effluents remains unknown. Thus, this study aimed to assess a physicochemical and cytotoxic characterization of chemicals used in the leather post-tanning process and to evaluate the contribution of each chemical to the pollution load of raw wastewater. This study was performed using a leather post-tanning formulation applied by a large tannery located in Brazil. Deacidulation agents caused high conductivity and dissolved solids in wastewater. Retanning agents (natural and synthetic tannins) were responsible for the largest inorganic pollution load, and synthetic tannins were more toxic than natural ones. Fatliquoring agents released the highest chemical oxygen demand load in wastewater and they were the chemical group that presented the highest toxicity. Fixing agent and black dye provided inorganic pollution load to wastewater, and nitrogen pollution of wastewater was mainly related to the neutralizing retanner and the black dye.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Análisis de la Demanda Biológica de Oxígeno , Brasil , Residuos Industriales , Curtiembre
7.
J Environ Manage ; 230: 456-463, 2019 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-30316036

RESUMEN

Tanneries are industries that may cause high environmental impact. Consequently, they are responsible for generating a large amount of wastewater with high concentrations of contaminants that require significant investment and operating costs in their treatment in order to accomplish the emission standards required by environmental legislation. This work has as main objective to minimize the environmental impact of the water used by tanneries through the study of reuse possibilities of wastewater tanning floats. The major concern is related to the pollutant chromium in the environment, since it is the tanning product that gives the best characteristics to leather and consequently the most used product. The reuse tests were performed on pilot and industrial scales. During the experiments, the following process control parameters were evaluated: pH, density, acid-base indicators for hide and shrinkage temperature. To validate the water reuse in tanneries, samples of wet-blue leather and residual floats were collected from pilot and industrial processes to perform chemical analyses to prove the validity of the process with reuse. Research has shown that reuse techniques, when properly evaluated, can be used in industries. In addition to reducing water demand, the reuse of wastewater in tanning processes minimizes the disposal of the wastewater with chromium and uses the residual chromium float.


Asunto(s)
Aguas Residuales/química , Agua/química , Cromo/química , Residuos Industriales/análisis , Industrias , Contaminantes del Agua/química
8.
Molecules ; 23(8)2018 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-30126123

RESUMEN

Because this issue journal is dedicated to Gelatin, here we present a few applications of gelatin in the field of optics. Optics is the science that studies the production, propagation, interaction and detection of light. Various materials sensitive to light (photosensitive) are used for detection of light, such as photomultipliers, CCDs, crystals, two dimensional (2D) materials and more. Among the 2D materials, the most popular for several centuries has been gelatin based photographic emulsion, which records spatial distributions of light. More recently (1970), films made of Gelatin with Dichromate (DCG) and dyes have been used. We describe some characteristics and applications of these two photosensitive materials. We also describe examples where gelatin is used as a Relative Humidity (RH) sensor and in the fabrication of optical elements based on gelatin. This article is intended for researchers outside the optics community.


Asunto(s)
Gelatina/química , Luz , Fenómenos Ópticos , Emulsiones , Concentración de Iones de Hidrógeno , Temperatura
9.
J Insect Physiol ; 107: 224-232, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29656100

RESUMEN

After the emergence of the Ceratitis capitata imago, the pale and folded wings are expanded and sclerotized to acquire the definitive form and to stabilize the cuticle. The wings of this fly show a specific pattern of brownish and black spots. Black spots are pigmented by melanin, whereas there was scarce information about the development of the brownish spots. N-beta-alanydopamine (NBAD) is the main tanning precursor in C. capitata body cuticle, and we hypothesized that it may be responsible for the colouration of the brownish spots. We determined the topology and timing of NBAD synthesis and deposition to attain the species-specific colouration pattern. We demonstrated that during the first hours the colour of the brownish spots was principally determined by the tanning of the hairs. Haemolymph circulation through the veins is required to tan the wings. We confirmed that soon after wing spreading, most of the wing epidermal cells disappeared. Thus, the tanning of the brown spots was accomplished when the wing lamina was devoid of cells. NBAD synthase (NBAD-S; Ebony protein in D. melanogaster) activity in wings was detected in pharate adults and lasted several days after the emergence, even after the end of the tanning process. This observation is in contrast to epidermal NBAD-S activity in the body, where it was nearly undetectable 48 h post emergence. Our results indicate that NBAD-S was exported and deposited into the extracellular matrix of the brown spot areas before cell death and that tanning occurs through gradual export of NBAD precursors (dopamine and b-alanine) from veins.


Asunto(s)
Ceratitis capitata/fisiología , Proteínas de Unión al ADN/genética , Proteínas de Insectos/genética , Pigmentación/genética , Alas de Animales/fisiología , Animales , Ceratitis capitata/genética , Color , Proteínas de Unión al ADN/metabolismo , Dopamina/análogos & derivados , Dopamina/química , Dopamina/metabolismo , Proteínas de Insectos/metabolismo , beta-Alanina/metabolismo
10.
J Basic Microbiol ; 58(4): 296-301, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29430723

RESUMEN

In artisanal tanneries, the skins are immersed in cereals fermented by natural microbial flora in order to reduce the pH of the skin, an essential condition for carrying out the final step. The environmental thermal variation alters the fermentation process and affects the quality of the final product. The aim of this work was to isolate lactic acid bacteria from cereals mixture fermented in an artisanal tannery and to evaluate in vitro the acidifying activity of the strains as a first step for the formulation of a starter culture. In most samples, a prevalence of cocci (95%) was observed with respect to bacilli. The best acidifying strains were identified by phenotypic and genotypic techniques as Enterococcus faecium CRL 1943 (rapid acidification at 37 °C) and Leuconostoc citreum CRL 1945 (high acidifying activity at 18 °C). In addition, the biomass production of the selected strains was analyzed at free and controlled pH (bioreactors 1.5 L). The production of biomass was optimal at controlled pH, with a higher growth (0.5-1.1 log units). Both strains were compatible, allowing their inclusion in a mixed culture. These lactic strains could contribute to the systematization of the tanning process.


Asunto(s)
Lactobacillales/aislamiento & purificación , Lactobacillales/metabolismo , Curtiembre/métodos , Reactores Biológicos , ADN Bacteriano/genética , Grano Comestible/microbiología , Enterococcus faecium/genética , Enterococcus faecium/crecimiento & desarrollo , Enterococcus faecium/aislamiento & purificación , Enterococcus faecium/metabolismo , Fermentación , Genotipo , Concentración de Iones de Hidrógeno , Ácido Láctico/biosíntesis , Lactobacillales/genética , Lactobacillales/crecimiento & desarrollo , Leuconostoc/genética , Leuconostoc/crecimiento & desarrollo , Leuconostoc/aislamiento & purificación , Leuconostoc/metabolismo , Fenotipo , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Temperatura
11.
Rev. costarric. salud pública ; 26(1): 22-29, ene.-jun. 2017.
Artículo en Español | LILACS | ID: biblio-844778

RESUMEN

ResumenEl cáncer de piel es la neoplasia más frecuente en Costa Rica.La constante exposición a luz ultravioleta es un factor de riesgo ampliamente reconocido para este cáncer.Las cámaras de bronceado que emiten radiación UV fueron clasificadas por un grupo de investigadores, IARC “International Agency for Research on Cáncer” como Grupo 1 “Cancerígeno para humanos”.El riesgo de melanoma aumenta en un 75% cuando las cámaras de bronceado son utilizadas en edades tempranas.Las campañas de salud enfocadas en foto protección han tenido un importante impacto en la prevención del cáncer de piel. Sin embargo, aún es necesario dar a conocer a la población general sobre la relación directa que existe entre el uso de fuentes artificiales de radiación ultravioleta (como cámaras de bronceado) con la aparición de cáncer de piel melanoma y no melanoma.


AbstractSkin cancer is the most common malignancy in Costa Rica.Constant exposure to ultraviolet light is a widely recognized risk factor for this neoplasm. Indoor tanning chambers that emit UV radiation were classified as Group 1 "Carcinogenic for humans" by the “International Agency for Research on Cancer” (IARC).The risk of melanoma increases in a 75% when the tanning beds are used in early ages.Health campaigns focused photo protective measures have had an important impact on skin cancer prevention.However, it is still necessary to inform general population about the direct relationship between the use of artificial sources of ultraviolet radiation like in tanning beds, with the development of melanoma and non-melanoma cancer.


Asunto(s)
Humanos , Neoplasias Cutáneas/diagnóstico , Cámaras de Bronceado , Melanoma/etiología , Costa Rica
12.
Photodermatol Photoimmunol Photomed ; 33(2): 68-74, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28039945

RESUMEN

BACKGROUND: The incidence of melanoma has been rising worldwide. One possible reason for this is natural and artificial UV exposure. Only little data on actual consumer statistics from tanning studios and the usage of sunscreen are available. Therefore, it is difficult to describe trends for both and identify the impact of preventive measures. METHODS: To gain knowledge about the popularity of 'tanning bed' and 'sunscreen', normalized search volumes for both search queries were obtained from Google Trends for 11 countries between January 2004 and June 2016. RESULTS: With few exceptions, worldwide interest in 'tanning bed' has been declining, whereas interest in 'sunscreen' has been increasing. The assessed countries from the Southern Hemisphere showed minor interest in tanning compared to the Northern Hemisphere. Both search queries were observed to fluctuate in a seasonal pattern. Skin cancer prevention measures influence the interest in tanning beds and sunscreen. CONCLUSION: Google Trends data can act as a first surrogate marker to evaluate the influence of skin cancer campaigns on the popularity of tanning beds and sunscreen. Fine-tuning of skin cancer campaigns according to seasonal and geographic trends and behaviors may help to maximize their success.


Asunto(s)
Conducta en la Búsqueda de Información , Internet/estadística & datos numéricos , Internet/tendencias , Motor de Búsqueda/estadística & datos numéricos , Baño de Sol , Protectores Solares , Australia , Brasil , Canadá , Francia , Humanos , Japón , Federación de Rusia , Estaciones del Año , Singapur , Baño de Sol/tendencias , Suecia , Turquía , Rayos Ultravioleta/efectos adversos , Reino Unido , Estados Unidos
13.
Anim Sci J ; 88(5): 807-816, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-27647827

RESUMEN

The aim was to compare the effects of two production systems on performance, carcass traits and physical-mechanical characteristics of leather from Beefalo-Nellore steers and heifers and to determine if the response to the production system was similar for both genders. A total of 40 Beefalo-Nellore cattle, 20 steers and 20 heifers, were evaluated. Animals were divided into two production systems: slaughtered at 15 (intensive system) or 26 (extensive system) months of age. In the intensive system, all animals received a ration containing 600 g/kg corn silage and 400 g/kg concentrate. In the extensive system, animals were kept on a pasture predominantly based on Brachiaria sp. and supplemented with 2 kg/day concentrate. In the intensive system, there was no difference in slaughter weight (470 kg body weight) between steers and heifers but steers in the extensive system had greater slaughter weight than heifers (463 and 428 kg body weight, respectively). Leather weight was higher for animals in the intensive than extensive system but there was no difference in leather weight once excess fat was removed. Leather quality from Beefalo-Nellore cattle slaughtered at 15 or 26 months of age is similar although carcass yield is higher for cattle slaughtered at a younger age.


Asunto(s)
Envejecimiento , Crianza de Animales Domésticos/métodos , Piel , Mataderos , Animales , Bovinos , Femenino , Masculino , Resistencia a la Tracción
14.
Electron. j. biotechnol ; Electron. j. biotechnol;19(6): 26-31, Nov. 2016. ilus
Artículo en Inglés | LILACS | ID: biblio-840309

RESUMEN

Background: The effect of diverse oxygen transfer coefficient on the L-erythrulose production from meso-erythritol by a newly isolated strain, Gluconobacter kondonii CGMCC8391 was investigated. In order to elucidate the effects of volumetric mass transfer coefficient (K La) on the fermentations, baffled and unbaffled flask cultures, and fed-batch cultures were developed in present work. Results: With the increase of the K La value in the fed-batch culture, L-erythrulose concentration, productivity and yield were significantly improved, while cell growth was not the best in the high K La. Thus, a two-stage oxygen supply control strategy was proposed, aimed at achieving high concentration and high productivity of L-erythrulose. During the first 12 h, Klawas controlled at 40.28 h-1 to obtain high value for cell growth, subsequently K La was controlled at 86.31 h-1 to allow for high L-erythrulose accumulation. Conclusions: Under optimal conditions, the L-erythrulose concentration, productivity, yield and DCW reached 207.9 ± 7.78 g/L, 6.50 g/L/h, 0.94 g/g, 2.68 ± 0.17 g/L, respectively. At the end of fermentation, the L-erythrulose concentration and productivity were higher than those in the previous similar reports.


Asunto(s)
Gluconobacter/metabolismo , Oxígeno/metabolismo , Tetrosas/biosíntesis , Reactores Biológicos , Eritritol , Fermentación , Curtiembre
15.
Health Psychol Res ; 4(1): 5453, 2016 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-27403462

RESUMEN

Indoor tanning (IT) has been linked with psychiatric and addictive symptoms, and frequent tanning may indicate tanning dependence (addiction). The current study evaluated the effects of an IT episode on mood states and the association of these effects with psychiatric and addictive symptoms among young adult female indoor tanners. One-hundred thirty-nine female university students aged 18-25 years who had indoor tanned completed an online survey including the Positive and Negative Affects Scales and a standardized psychiatric interview (the MINI International Neuropsychiatric Interview) via telephone. Psychiatric and addictive symptoms were relatively common among these young adult female indoor tanners. Overall, participants reported significant decreases in both negative (upset, scared, irritable, nervous, jittery, afraid) and positive (feeling interested) mood states after their most recent tanning episode. Multivariable linear regression analyses showed that more frequent indoor tanning in the past month and symptoms of illicit drug use disorders were associated with decreases in negative mood, and symptoms of generalized anxiety disorder were associated with a decrease in feeling interested. In summary, indoor tanners report relatively high rates of psychiatric and substance use symptoms, including symptoms of tanning dependence, and indoor tanning appears to alter mood. Women with certain substance use and psychiatric characteristics may be more vulnerable to such mood changes after tanning indoors. Further research is needed to clarify the relationships among these variables.

16.
J Pediatr Adolesc Gynecol ; 28(4): 275-83, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26119073

RESUMEN

Young, non-Hispanic white females represent the population most likely to use indoor tanning facilities. This population may be at increased risk of skin cancer as recent meta-analyses support a strong association between cutaneous malignancy and indoor tanning. Public perception of the purported health benefits of indoor tanning may be partially to blame for the popularity of tanning salons as a desire to prepare skin prior to sun exposure is among the most commonly cited motivations for indoor tanning. Improving education and counseling to address misconceptions regarding tanning safety will require the participation of healthcare providers for both physical and psychological screenings as well as for information dissemination. This review presents the association between tanning bed use and skin cancer, biological effects of UV radiation exposure, UV burden associated with tanning devices, public perception of tanning, demographic and psychological profile of indoor tanners, and current legislation regulating tanning bed use.


Asunto(s)
Neoplasias Cutáneas/etiología , Baño de Sol , Rayos Ultravioleta/efectos adversos , Adulto , Femenino , Salud Global , Humanos , Morbilidad/tendencias , Factores de Riesgo , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/epidemiología , Adulto Joven
17.
Arq. Inst. Biol ; 76(2)2009.
Artículo en Portugués | LILACS-Express | VETINDEX | ID: biblio-1462020

RESUMEN

ABSTRACT Oligonychus ilicis (McGregor, 1917), is one of the main phytophagous mites of the coffee plant ( Coffea spp.), although it is not reported among the primary pests. They live on the upper surface of the leaves, puncturing the epidermis and mesophyll cells to absorb and feed on the extravasated cellular content. In consequence, the leaves lose their natural shine and become tan. The objective of this work was to quantify the photosynthetic rate of coffee-plant leaves presenting different infestation levels of O. ilicis. The study was carried out in potted three-year-old coffee plants ( Coffea arabica L., Catuaí cultivar), kept in a greenhouse. Infestations were accomplished at five different levels (0, 15, 30, 60 and 120 adult mite females/leaf), with mites coming from a stock rearing, on leaves of the third pair starting from the apex and totally expanded, located in branches from the middle third of the plant, with five repetitions. The potential photosynthesis was measured through the photosynthetic oxygen produced, using an oxygen monitor with a Clark type electrode coupled to a CB1 electric flow control box. The evaluations were made 7 and 21 days after the infestation with the mites, and the data obtained were submitted to regression analysis. There was a negative correlation between levels of infestation and potential photosynthesis, whereas at levels 15, 30, 60 and 120 mites/leaf, the photosynthetic rates were reduced in relation to the control treatment, in 37.2, 38.7; 46.0 and 50.1% respectively.


RESUMO Oligonychus ilicis (McGregor, 1917) é um dos principais ácaros fitófagos do cafeeiro ( Coffea spp.), embora não esteja relacionado entre as pragas primárias. Esses ácaros vivem na superfície superior das folhas e, para se alimentar, perfuram as células da epiderme e do mesófilo e absorvem o conteúdo celular extravasado. Em consequência, as folhas perdem o brilho natural e tornam-se bronzeadas. O objetivo deste trabalho foi quantificar a taxa de fotossíntese de folhas de cafeeiro apresentando diferentes níveis de infestação de O. ilicis. O estudo foi realizado em plantas de cafeeiro (Coffea arabica L., cultivar Catuaí) envasadas e com três anos de idade, mantidas em casa de vegetação. Foram realizadas infestações em cinco diferentes níveis (0, 15, 30, 60 e 120 fêmeas adultas do ácaro/folha), com ácaros provenientes da criação de manutenção, em folhas do terceiro par, a partir do ápice e totalmente expandidas, localizadas em ramos do terço médio da planta, com cinco repetições. A medição da fotossíntese potencial foi realizada por meio do oxigênio fotossintético produzido, utilizando-se de um monitor de oxigênio com eletrodo tipo Clark acoplado a uma caixa de controle de fluxo elétrico CB1. As avaliações foram realizadas 7 e 21 dias após a infestação com os ácaros, e os dados obtidos foram submetidos a uma análise de regressão. Houve correlação negativa entre os diferentes níveis de infestação e a fotossíntese potencial, sendo que, nos níveis 15, 30, 60 e 120 ácaros/folha, as taxas de fotossíntese foram reduzidas, em relação ao tratamento-testemunha, em 37,2; 38,7; 46,0 e 50,1%, respectivamente.

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