DNA Barcoding unveils cryptic lineages of Hoplias malabaricus from Northeastern Brazil / DNA Barcoding revela linhagens crípticas de Hoplias malabaricus no nordeste do Brasil

Abstract The trahira or wolf fish - Hoplias malabaricus- is a valid species, although recent cytogenetic and molecular studies have indicated the existence of a species complex. In this context, the present study analyzed the mitochondrial COI marker to determine the levels of genetic diversity of specimens from the Brazilian state of Maranhão, and verify the occurrence of distinct lineages within the study area. Samples were collected from the basins of the Turiaçu, Pindaré, Mearim, Itapecuru, and Parnaíba rivers. A 630-bp fragment was obtained from 211 specimens, with 484 conserved and 108 variable sites, and 60 haplotypes (Hd = 0,947; π = 0,033). The phylogenetic analyses indicated the existence of three distinct lineages of H. malabaricus from Maranhão. Genetic distances of 1.5-8.2% were found between all the populations analyzed, while the variation between haplogroups ranged from 2.1% to 7.7%. The AMOVA indicated that most of the molecular variation was found among groups, with high FST values. The high levels of genetic variability found in the present study are supported by the available cytogenetic data. These findings reinforce the need for the development of effective programs of conservation and management independently for each river basin, in order to preserve the genetic variability found in this taxon.

Resumo A traíra - Hoplias malabaricus- é uma espécie válida, embora recentes estudos citogenéticos e moleculares tenham indicado a existência de um complexo de espécies. Neste contexto, o presente estudo analisou o marcador mitocondrial COI para determinar os níveis de diversidade genética dos espécimes do estado do Maranhão e verificar a ocorrência de linhagens distintas dentro da área de estudo. As amostras foram coletadas nas bacias dos rios Turiaçu, Pindaré, Mearim, Itapecuru e Parnaíba. As análises filogenéticas indicaram a existência de três linhagens distintas nas populações do Maranhão. Obteve-se um fragmento de 630 pb de 211 espécimes, com 484 sítios conservados, 108 variáveis e 60 haplótipos (Hd = 0,947; π = 0,033). As análises filogenéticas indicaram a ocorrência de três linhagens distintas de H. malabaricus do Maranhão. Distâncias genéticas de 1.5 a 8.2% foram encontradas entre todas as populações analisadas, enquanto a variação entre os haplogrupos variou de 2.1% a 7.7%. A AMOVA indicou que a maior variação molecular foi entre os grupos, com altos valores de FST. Os altos níveis de variabilidade genética encontrados no presente estudo são suportados pelos dados citogenéticos disponíveis. Essas descobertas reforçam a necessidade de desenvolver programas de conservação e manejo independentemente para cada bacia hidrográfica, a fim de preservar a variabilidade genética encontrada neste táxon.

DNA Barcoding unveils cryptic lineages of Hoplias malabaricus from Northeastern Brazil.

The trahira or wolf fish - Hoplias malabaricus- is a valid species, although recent cytogenetic and molecular studies have indicated the existence of a species complex. In this context, the present study analyzed the mitochondrial COI marker to determine the levels of genetic diversity of specimens from the Brazilian state of Maranhão, and verify the occurrence of distinct lineages within the study area. Samples were collected from the basins of the Turiaçu, Pindaré, Mearim, Itapecuru, and Parnaíba rivers. A 630-bp fragment was obtained from 211 specimens, with 484 conserved and 108 variable sites, and 60 haplotypes (Hd = 0,947; π = 0,033). The phylogenetic analyses indicated the existence of three distinct lineages of H. malabaricus from Maranhão. Genetic distances of 1.5-8.2% were found between all the populations analyzed, while the variation between haplogroups ranged from 2.1% to 7.7%. The AMOVA indicated that most of the molecular variation was found among groups, with high FST values. The high levels of genetic variability found in the present study are supported by the available cytogenetic data. These findings reinforce the need for the development of effective programs of conservation and management independently for each river basin, in order to preserve the genetic variability found in this taxon.

Electron scattering from 1-butanol at intermediate impact energies: Total cross sections.

We report experimental measurements of the absolute total cross sections (TCSs) for electron scattering from 1-butanol at impact energies in the range 80-400 eV. Those measurements were conducted by considering the attenuation of a collimated electron beam, at a given energy, through a gas cell containing 1-butanol, at a given pressure, and through application of the Beer-Lambert law to derive the required TCS. We also report theoretical results using the Independent-Atom Model with Screening Corrected Additivity Rule and Interference approach. Those results include the TCS, the elastic integral cross section (ICS), the ionization total ICS, and the sum over all excitation process ICSs with agreement at the TCS level between our measured and calculated results being encouraging.

Total cross sections for electron scattering by 1-propanol at impact energies in the range 40-500 eV.

Absolute total cross section (TCS) measurements for electron scattering from 1-propanol molecules are reported for impact energies from 40 to 500 eV. These measurements were obtained using a new apparatus developed at Juiz de Fora Federal University-Brazil, which is based on the measurement of the attenuation of a collimated electron beam through a gas cell containing the molecules to be studied at a given pressure. Besides these experimental measurements, we have also calculated TCS using the Independent-Atom Model with Screening Corrected Additivity Rule and Interference (IAM-SCAR+I) approach with the level of agreement between them being typically found to be very good.

Late mandibular fracture occurring in the postoperative period after third molar removal: systematic review and analysis of 124 cases.

Factors associated with the diagnosis, aetiology, and treatment of mandibular fractures occurring during the postoperative period following the removal of a lower third molar are discussed. The following databases were searched using specific key words: PubMed/MEDLINE, LILACS, Embase, and Scopus. The search yielded 124 cases. Sex, age, side, tooth position and angulation, bone impaction, relationship between the tooth and the inferior alveolar nerve, local pathological conditions, aetiology of the fracture, symptomatology, and time between surgery and fracture, as well as any displacement of the fracture and the treatment of the fracture, were evaluated. Data were tabulated and the χ2 statistical test was applied (P<0.05). Male patients aged >35 years, with teeth in positions II/III and B/C, complete bony impaction, and local bone-like alterations, were found to have a higher frequency of fracture and pericoronitis (P<0.05). Late fractures generally occurred between the second and fourth postoperative weeks (P<0.05). They were generally not displaced and the typical treatment was the non-surgical approach (P<0.05). It is concluded that the risk of mandibular fracture after extraction is associated with excessive ostectomy and/or local alterations. At-risk patients should be thoroughly briefed on the importance of a proper postoperative diet.

DNA Barcoding unveils cryptic lineages of Hoplias malabaricus from Northeastern Brazil

Abstract The trahira or wolf fish - Hoplias malabaricus- is a valid species, although recent cytogenetic and molecular studies have indicated the existence of a species complex. In this context, the present study analyzed the mitochondrial COI marker to determine the levels of genetic diversity of specimens from the Brazilian state of Maranhão, and verify the occurrence of distinct lineages within the study area. Samples were collected from the basins of the Turiaçu, Pindaré, Mearim, Itapecuru, and Parnaíba rivers. A 630-bp fragment was obtained from 211 specimens, with 484 conserved and 108 variable sites, and 60 haplotypes (Hd = 0,947; = 0,033). The phylogenetic analyses indicated the existence of three distinct lineages of H. malabaricus from Maranhão. Genetic distances of 1.5-8.2% were found between all the populations analyzed, while the variation between haplogroups ranged from 2.1% to 7.7%. The AMOVA indicated that most of the molecular variation was found among groups, with high FST values. The high levels of genetic variability found in the present study are supported by the available cytogenetic data. These findings reinforce the need for the development of effective programs of conservation and management independently for each river basin, in order to preserve the genetic variability found in this taxon.

Resumo A traíra - Hoplias malabaricus- é uma espécie válida, embora recentes estudos citogenéticos e moleculares tenham indicado a existência de um complexo de espécies. Neste contexto, o presente estudo analisou o marcador mitocondrial COI para determinar os níveis de diversidade genética dos espécimes do estado do Maranhão e verificar a ocorrência de linhagens distintas dentro da área de estudo. As amostras foram coletadas nas bacias dos rios Turiaçu, Pindaré, Mearim, Itapecuru e Parnaíba. As análises filogenéticas indicaram a existência de três linhagens distintas nas populações do Maranhão. Obteve-se um fragmento de 630 pb de 211 espécimes, com 484 sítios conservados, 108 variáveis e 60 haplótipos (Hd = 0,947; = 0,033). As análises filogenéticas indicaram a ocorrência de três linhagens distintas de H. malabaricus do Maranhão. Distâncias genéticas de 1.5 a 8.2% foram encontradas entre todas as populações analisadas, enquanto a variação entre os haplogrupos variou de 2.1% a 7.7%. A AMOVA indicou que a maior variação molecular foi entre os grupos, com altos valores de FST. Os altos níveis de variabilidade genética encontrados no presente estudo são suportados pelos dados citogenéticos disponíveis. Essas descobertas reforçam a necessidade de desenvolver programas de conservação e manejo independentemente para cada bacia hidrográfica, a fim de preservar a variabilidade genética encontrada neste táxon.

A quasi-classical trajectory study of the OH + SO reaction: the role of ro-vibrational energy.

A study of the OH + SO → H + SO2 reaction using a quasi-classical trajectory method is presented with the aim of investigating the role of the ro-vibrational energy of the reactants in the reactivity. The calculations were carried out using a previously reported global potential energy surface for HSO2((2)A). Different initial conditions with one and both reactants ro-vibrationally excited were studied. The reactive cross sections, for each studied combination, are calculated and then fitted to a capture-like model combined with a factor accounting for the recrossing effects. The Vibrational Energy Quantum Mechanical Threshold of the Complex method was used to correct for the zero-point vibrational energy leakage of the classical calculations. State specific and averaged rate constants are reported. The reactivity is affected when ro-vibrational energy of either of the reactants is changed. The present calculations provide a theoretical support for the experimental rate constant for temperatures below 550 K, but fail to account for the significant fall in the observed rate constant upon increasing the temperature above this value.

Fatigue is mediated by cholinoceptors within the ventromedial hypothalamus independent of changes in core temperature.

We investigated brain mechanisms modulating fatigue during prolonged physical exercise in cold environments. In a first set of studies, each rat was subjected to three running trials in different ambient temperatures (T(a)). At 8 °C and 15 °C, core body temperature (T(core)) decreased and increased, respectively, whereas at 12 °C, the T(core) did not change throughout the exercise. In another set of experiments, rats were randomly assigned to receive bilateral 0.2 µL injections of 2.5 × 10(-2) M methylatropine or 0.15 M NaCl solution into the ventromedial hypothalamic nuclei (VMH). Immediately after the injections, treadmill exercise was started. Each animal was subjected to two experimental trials at one of the following T(a) : 5 °C, 12 °C or 15 °C. Muscarinic blockade of the VMH reduced the time to fatigue (TF) in cold environments by 35-37%. In all T(a) studied, methylatropine-treated rats did not present alterations in T(core) and tail skin temperature compared with controls. These results indicate that, below the zone of thermoneutrality, muscarinic blockade of the VMH decreases the TF, independent of changes in T(core). In conclusion, our data suggest that VMH muscarinic transmission modulates physical performance, even when the effects of thermoregulatory adjustments on fatigue are minimal.

Physical exercise-induced cardiovascular adjustments are modulated by muscarinic cholinoceptors within the ventromedial hypothalamic nucleus.

The effects of blocking ventromedial hypothalamic nucleus (VMH) muscarinic cholinoceptors on cardiovascular responses were investigated in running rats. Animals were anesthetized with pentobarbital sodium and fitted with bilateral cannulae into the VMH. After recovering from surgery, the rats were familiarized to running on a treadmill. The animals then had a polyethylene catheter implanted into the left carotid artery to measure blood pressure. Tail skin temperature (T(tail)), heart rate, and systolic, diastolic and mean arterial pressure were measured after bilateral injections of 0.2 microl of 5 x 10(-9) mol methylatropine or 0.15 M NaCl solution into the hypothalamus. Cholinergic blockade of the VMH reduced time to fatigue by 31 % and modified the temporal profile of cardiovascular and T(tail) adjustments without altering their maximal responses. Mean arterial pressure peak was achieved earlier in methylatropine-treated rats, which also showed a 2-min delay in induction of tail skin vasodilation, suggesting a higher sympathetic tonus to peripheral vessels. In conclusion, muscarinic cholinoceptors within the VMH are involved in a neuronal pathway that controls exercise-induced cardiovascular adjustments. Furthermore, blocking of cholinergic transmission increases sympathetic outflow during the initial minutes of exercise, and this higher sympathetic activity may be responsible for the decreased performance.

Comparative cytogenetics study between Triatoma maculata and Triatoma pseudomaculata (Triatominae, Heteroptera)

Triatomines are vectors of the protozoan Trypanosoma cruzi, the etiological agent of Chagas’ disease. These hematophagous insects belong to the order Heteroptera and to the family Reduviidae. Disseminated throughout large portions of Brazil and of other Latin American countries, Chagas’ disease is a serious and important public health problem that is difficult to treat. Cytogenetically, the interest in triatomines is in its holocentric chromosomes and in its uncommon meiosis process; sexual segregation is post-reductional. The basic number of chromosomes in triatomines is 2n = 22. We analyzed spermatogenesis in Triatoma maculata and T. pseudomaculata, with emphasis on the following aspects: spermatogenesis phases, chromatin and meiotic chromosome structure and the nucleolar cycle. These species are found principally in northeastern Brazil and are potential vectors for T. cruzi. The specimens were supplied by the insectary of the Special Health Service of Araraquara (SESA), Department of Epidemiology, School of Public Health, University of São Paulo. Cells were obtained from the testicles of adult males; after crushing they were submitted to the following cytochemical techniques: lacto-acetic orcein staining, impregnation with silver ions, C-banding and critical electrolyte concentrations. An association was observed between the nucleolus and heterochromatic regions, in both interphasic somatic cells and germ line. The localization of these specific regions also demonstrated an intimate functional relationship between these structures. The karyograms of the two species, mounted at metaphase I, indicated 10 autosomes and one pair of sexual chromosomes (22 chromosomes), coinciding with the modal number for the group. With C-banding, the Y chromosome is heterochromatic in both species...

Intracerebroventricular physostigmine enhances blood pressure and heat loss in running rats.

The aim of this study was to evaluate the effects of the stimulation of central cholinergic synapses in the regulation of heat loss in untrained rats during exercise. The animals were separated into two groups (exercise or rest) and tail skin temperature (T(tail)), core temperature and blood pressure were measured after injection of 2 microL of 5x10(-3) M physostigmine (Phy; n = 8) or 0.15 M NaCl solution (Sal; n = 8) into the lateral cerebral ventricle. Blood pressure was recorded by a catheter implanted into the abdominal aorta, T(tail) was measured using a thermistor taped to the tail and intraperitoneal temperature (T(b)) was recorded by telemetry. During exercise, Phy-treated rats had a higher increase in mean blood pressure (147 +/- 4 mmHg Phy vs. 121 +/- 3 mmHg Sal; P < 0.001) and higher T(tail) (26.4 +/- 1.0 degrees C Phy vs. 23.8 +/- 0.5 degrees C Sal; P < 0.05) that was closely related to the increase in systolic arterial pressure (r = 0.83; P < 0.001). In addition, Phy injection attenuated the exercise-induced increase in T(b) compared with controls without affecting running time. We conclude that the activation of central cholinergic synapses during exercise increases heat dissipation due to the higher increase in blood pressure.

Histopathological findings in skeletal muscle used in human dynamic cardiomyoplasty.

Patients submitted to dynamic cardiomyoplasty had an initial clinical improvement followed by a decrease in cardiac failure indices. A histopathological study of the skeletal muscle was undertaken to explain this. Latissimus dorsi fragments from 15 patients submitted to dynamic cardiomyoplasty in a 1:1 (heart beat:muscle stimulation) conditioning were analysed by light microscopy. The interval between surgery and obtaining the specimens (13 from necropsies, two from heart transplants) ranged from 37 days to 6 years. Nuclear clumps and internalization, the presence of round fibres, inflammation, and fibrosis were analysed semi-quantitatively; the thickness of muscle fibres and the percentage of tissue fat were measured by image analysis. The quantitative data were also compared, in 12 cases, with gender- and age-matched necropsy controls. The mean thickness of muscle fibres in cases and controls was 27.21+/-5.33 and 40.84+/-9.42 microm, respectively (p=0.001). The percentage of tissue fat in cases and controls was 12.04+/-12.66% and 0.93+/-0.91%, respectively (p=0.008). The duration of grafts correlated positively with the quantity of nuclear clumps (R=0.80, p<0.001) and round fibres (R=0.53, p=0.04), as well as with the percentage of tissue fat (R=0.68, p=0.005). Accordingly, a negative correlation was found between the duration of grafts and the mean diameter of fibres, characterizing muscle atrophy (R=-0.66, p=0.01). The longer the post-surgical period, the more intense the degenerative lesions. This study shows that skeletal muscle used in human dynamic cardiomyoplasty may atrophy and be replaced by fat when stimulation is synchronized to every cardiac beat. These findings could play a role in explaining the long-term results of this surgical procedure.

Yellow fever vaccination during pregnancy and spontaneous abortion: a case-control study.

OBJECTIVE: To assess a possible association between Yellow fever (YF) vaccine (inadvertently) administered during early pregnancy and spontaneous abortion. METHOD: A hospital-based case-control study conducted in a Brazilian town after a YF vaccine campaign that followed an epidemic of dengue. The study included 39 women who attended a university hospital with spontaneous abortion (cases) and 74 pregnant women attending the antenatal clinic of that hospital (controls). RESULTS: The crude odds ratio (relative risk estimate) of this association was 2.49, which dropped to 2.29 (95% CI 0.65-8.03) when adjusted for several confounders by multiple logistic regression. Dengue and exposure to organophosphate insecticide fogging during pregnancy were not associated with spontaneous abortion. CONCLUSION: This study, although small and with low power, provides some evidence that women vaccinated with YF vaccine during early pregnancy have an increased risk of having spontaneous abortion. Based on these findings a sensible recommendation should be to avoid YF vaccination of pregnant women unless their risk of acquiring YF outweighs the risk of vaccine-related abortion.

Withdrawal following cocaine self-administration decreases regional cerebral metabolic rate in critical brain reward regions.

The quantitative [14C]-2-deoxyglucose autoradiographic method was utilized to assess regional cerebral metabolic rate for glucose (rCMRglc) in rat brain during withdrawal from cocaine self-administration. RCMRglc was determined in 62 regions from brains of naive rats which were placed into an empty operant chamber for 12 hr continuously, and rats trained to self-administer cocaine during 3 hr training sessions and subsequently placed into the operant chamber for 12 hr continuously with or without access to cocaine. Animals placed into the chamber without access to cocaine were examined 6 hr later, while animals allowed access to the 12 hr cocaine binge were examined either 6 or 72 hr post-cocaine. Metabolic activity was reduced during withdrawal in the nucleus accumbens, olfactory tubercle, islands of Calleja region, basolateral and central amygdaloid nuclei, medial septum, piriform and cingulate cortices, rostral caudatoputamen, entopeduncular nucleus and the adjacent lateral hypothalamus, somatosensory, auditory, and motor cortices compared to the naive state. These effects were usually more severe at 72 than at 6 hr after binge exposure, with intermediate values observed in cocaine trained animals without binge exposure. The response was negatively correlated with the amount of cocaine consumed during binge exposure in the striatum, olfactory tubercle, piriform, cingulate, somatosensory, and motor cortices. Thus, the amount of cocaine consumed can affect the extent of metabolic depression after sustained drug exposure. The pattern of regional effects suggests that mesolimbic and rostral extrapyramidal dopamine terminal regions and certain of their efferent pathways are preferentially affected during cocaine withdrawal. The reduction of basal metabolic rate observed in these brain regions during cocaine withdrawal may become more severe with time despite the apparent recovery of certain behavioral-motivational responses.

South American blastomycosis of epididymis.

Reported herein is the first Brazilian case of epididymal involvement by South American blastomycosis, and apparently the second case to be reported in the world literature.