Gas exchange and osmotic adjustment in cotton cultivars subjected to severe salt stress.

Salinity is harmful to crops when the concentration of soluble salts overcomes the salinity threshold of the crop, causing osmotic stress and limitations in plant growth. In this scenario, adopting tolerant cultivars is the most adequate strategy to minimize agricultural losses. However, the inheritance of tolerance depends on the genotype. From this perspective, this study assessed the tolerance to severe salt stress in 11 cotton cultivars based on gas exchange parameters and the free proline content. The cultivars were grown in a greenhouse and subjected to 34 days of saline irrigation (10 dS m-1), starting 45 days after seedling emergence (B1 phase). Plant growth was monitored weekly until the end of the salt stress period. The treatments consisted of a combination of two factors: eleven cultivars associated with two electrical conductivity levels of irrigation water (ECw: 0.3 and 10.0 dS m-1). The experimental design was in randomized blocks in a 11 × 2 factorial arrangement with three replications (66 plots), with the experimental unit consisting of one plant per plot. Salinity impacted plant growth, being reflected on the gas exchange and free proline data of most cultivars. However, BRS 286, FMT 705, BRS 416, and BRS Acácia, and CNPA 7MH withstood the effects of stress and osmotically adjusted to the salt stress conditions, thus minimizing the damage to growth. Those cultivars are the most indicated for improvement programs aiming at tolerance to salt stress based on the results found in this research.

Involvement of the glutamatergic system in the nociception induced intrathecally for a TRPA1 agonist in rats.

The transient receptor potential ankyrin 1 (TRPA1) is expressed in peripheral and spinal terminals of sensory neurons, jointly to the vanilloid receptor (TRPV1). A relevant peripheral role of TRPA1 receptor has been implicated in a variety of processes, including the detection of noxious cold, and diverse painful stimulus, but the functional role of TRPA1 receptor in nociceptive transmission at spinal cord in vivo is poorly known. Therefore, the aim of this study was to evaluate whether the glutamatergic system is involved in the transmission of nociceptive stimulus induced for a TRPA1 agonist in the rat spinal cord. We observed that cinnamaldehyde, a TRPA1 agonist, on spinal cord synaptosomes leads to an increase in [Ca(2+)](i) and a rapid release of glutamate, but was not able to change the specific [(3)H]-glutamate binding. In addition, spinally administered cinnamaldehyde produced heat hyperalgesia and mechanical allodynia in rats. This behavior was reduced by the co-injection (i.t.) of camphor (TRPA1 antagonist) or MK-801 (N-methyl-D-aspartate (NMDA) receptor antagonist) to cinnamaldehyde. Besides, the pretreatment with resiniferatoxin (RTX), a potent TRPV1 agonist, abolished the cinnamaldehyde-induced heat hyperalgesia. Here, we showed that intrathecal RTX results in a decrease in TRPA1 and TRPV1 immunoreactivity in dorsal root ganglion. Collectively, our results demonstrate the pertinent participation of spinal TRPA1 in the possible enhancement of glutamatergic transmission of nociceptive signals leading to increase of the hypersensitivity, here observed as heat hyperalgesia. Then the modulation of spinal TRPA1 might be a valuable target in painful conditions associated with central pain hypersensitivity.

Hypoxic-ischemic brain injury stimulates inflammatory response and enzymatic activities in the hippocampus of neonatal rats.

Brain damage from neonatal hypoxia-ischemia (HI) plays a major role in neonatal mortality and morbidity. Using the Rice-Vannucci model of HI in rats, we verified that 8 days after HI injury, adenosine deaminase (ADA), N-acetyl-glucosaminidase (NAG) and myeloperoxidase (MPO) activities increased in the left hemisphere hippocampus (HI group); however, the activity of 5'-nucleotidase (5'NT) remained unchanged. In the hematoxylin-eosin analysis (HE), we detected selective and delayed degeneration of hippocampal pyramidal neurons and astroglial reaction accompanied by glial fibrillary acidic protein (GFAP)-positive and vimentin-positive in the immunohistochemistry analysis in the HI group compared with the control group. We observed the selective necrosis of neurons, vascular endothelial proliferation and inflammatory response accompanied by the increase of the key enzyme of adenosine metabolism in the HI group. The increase of ADA activity, despite the 5'NT activity was not altered, indicates the predominance of ADA activity in the postischemic homeostasis of extra cellular adenosine. The presence of leukocytes into the ischemic areas displays the possible importance of the neutrophil-macrophages associated with the increase of MPO and NAG activities 8 days after HI. These findings may contribute to the evaluation of some consequences of the damage caused by neonatal HI.

Anomalous compressibility of ferropericlase throughout the iron spin cross-over.

The thermoelastic properties of ferropericlase Mg(1-x)Fe(x)O (x = 0.1875) throughout the iron high-to-low spin cross-over have been investigated by first principles at Earth's lower mantle conditions. This cross-over has important consequences for elasticity such as an anomalous bulk modulus (K(S)) reduction. At room temperature the anomaly is somewhat sharp in pressure but broadens with increasing temperature. Along a typical geotherm it occurs across most of the lower mantle with a more significant K(S) reduction at approximately 1,400-1,600 km depth. This anomaly might also cause a reduction in the effective activation energy for diffusion creep and lead to a viscosity minimum in the mid-lower mantle, in apparent agreement with results from inversion of data related with mantle convection and postglacial rebound.

Chromosome reduction in Eleocharis maculosa (Cyperaceae).

Chromosome numbers in Cyperaceae lower than the typical basic number x = 5 have been described for only three species: Rhynchospora tenuis (n = 2), Fimbristylis umbellaris (n = 3) and Eleocharis subarticulata (n = 3). Eleocharis maculosa is recorded here as the fourth species of Cyperaceae that has a chromosome number lower than 2n = 10, with 2n = 8, 7 and 6. The karyotype differentiation in E. maculosa was studied using conventional staining (mitosis and meiosis), FISH with 45S and 5S rDNA and telomere probes. The results allow us to determine which chromosomes of the chromosome race with 2n = 10 fused to form the remaining reduced numbers, as well as to understand how the symploidy and translocation mechanisms were important in karyotype differentiation and the formation of chromosome races in Eleocharis.

Parallel and orthogonal stimulus in ultradiluted neural networks.

Extending a model due to Derrida, Gardner, and Zippelius, we have studied the recognition ability of an extreme and asymmetrically diluted version of the Hopfield model for associative memory by including the effect of a stimulus in the dynamics of the system. We obtain exact results for the dynamic evolution of the average network superposition. The stimulus field was considered as proportional to the overlapping of the state of the system with a particular stimulated pattern. Two situations were analyzed, namely, the external stimulus acting on the initialization pattern (parallel stimulus) and the external stimulus acting on a pattern orthogonal to the initialization one (orthogonal stimulus). In both cases, we obtained the complete phase diagram in the parameter space composed of the stimulus field, thermal noise, and network capacity. Our results show that the system improves its recognition ability for parallel stimulus. For orthogonal stimulus two recognition phases emerge with the system locking at the initialization or stimulated pattern. We confront our analytical results with numerical simulations for the noiseless case T = 0.

Largest and second largest cluster statistics at the percolation threshold of hypercubic lattices.

We investigate the scale invariance of the average ratio between the masses of the largest and second largest clusters at percolation. We employ a finite size scaling method to estimate percolation thresholds based on the simulations of relatively small lattices, and report on estimates for p(c) in hypercubic lattices with d=2-7, in full agreement with the best literature estimates. Also, we find the critical mass ratio to be strongly dependent on the boundary conditions, decreasing with the lattice dimension. Further, we compute several relevant mass distribution functions associated with the two largest clusters, which approach to limiting distributions for d>6. Finally, we discuss the main relevant features of the mass distributions in light of the relative role played by the spanning and nonspanning clusters.

Effect of the Cymbopogon citratus, Maytenus ilicifolia and Baccharis genistelloides extracts against the stannous chloride oxidative damage in Escherichia coli.

Stannous ion has been used in different sectors of human interest, such as in food industry and in health sciences. Much is known about stannous chloride (SnCl(2)) toxicity, although, there is no general agreement regarding its genotoxicity. Cymbopogon citratus, Maytenus ilicifolia and Baccharis genistelloides extracts have been used in popular medicine. We evaluated the influence of these crude extracts on the survival of the Escherichia coli wild type (AB 1157) strain submitted to SnCl(2) treatment. Reactive oxygen species (ROS) can be generated by a Fenton like reaction induced by SnCl(2). E. coli culture was treated simultaneously with SnCl(2) and a specific extract. Our results showed a reduction of the SnCl(2) effect on the survival of the cultures in presence of the crude extracts. The extract of M. ilicifolia showed the highest level of protection action against the SnCl(2) effect in comparison with the other extracts. This protector effect could due to the redox properties of these crude extracts. The compounds in the crude extracts could (i) chelate stannous ions, protecting them against the oxidation and avoiding the generation of ROS, (ii) be a scavenger of the ROS generated by the SnCl(2) oxidation and/or (iii) have oxidant compounds that could oxidise the stannous ions, abolishing or reducing the SnCl(2) effect.

[Use of dust and air as indicators of environmental pollution in areas adjacent to a source of stationary lead emission]. / Uso da poeira e do ar como indicadores de contaminação ambiental em áreas circunvizinhas a uma fonte de emissão estacionária de chumbo.

This study measured lead concentrations in both the outdoor air and household dust from houses located around a lead-acid battery repair shop. Such installations are one of the largest sources of lead exposure, since outdated technology is still used, coupled with the lack of strict air-quality control programs. Measurements of the air lead concentration around the repair shop were carried out at 6 points, approximately 25 and 500 m from the shop. Over 50% of the air samples exceeded the limit of 1.5 microg Pb.m-3 (range 0.03 - 183.3 microg Pb.m-3). House dust samples were collected from 6 places in houses located at approximately 25, 50, and 500 m from the repair shop, and the concentration of 1,500 microg Pb.m-2 for lead in house dust was exceeded in 44% of the samples, with results varying from 2.2 to 54,338.9 microg Pb.m-2.

[Cockayne syndrome. Case report]. / Síndrome de Cockayne. Relato de caso.

We describe a girl with Cockayne syndrome (CS), the diagnostic criteria and the complications of this syndrome. The required criteria for the diagnosis include: prenatal poor growth failure, congenital structural eye anomalies, cataracts, pigmentary retinopathy, severe neurologic dysfunction from birth, sensorineural hearing loss, cutaneous photosensitivity and dental caries. CS is a rare autosomal recessive and biochemical disorder.

Avaliaçäo morfométrica de fibras nervosas do nervo ulnar após reparaçäo cirúrgica com auto-enxerto e prótese tubular em cäes / Morphometric evaluation of nerve fibers after surgical repair by allograft and tubular prothesis of the ulnar nerve in dogs

O objetivo da investigaçäo foi o de comparar os resultados observados por meio de avaliaçäo morfométrica de fibras nervosas regeneradas, em cäes, após 26 semanas da reparaçäo cirúrgica de falhas do nervo ulnar, através de auto-enxertos e próteses tubulares de silicone. Para cada procedimento foram utilizados quatro animais. Dos nervos regenerados e dos enxertos foram retirados segmentos para avaliaçäo em nível de microscopia eletrônica. De cada corte foram amostrados seis campos distintos com 1,750µm elevado ao quadrado cada, que foram fotografados com aumentos de 1.880 vezes. Através de sistema computadorizado de morfometria (SigmaScan - Jandel Co., USA), obtiveram-se os seguintes parâmetros: diâmetros das fibras mielínicas; diâmetros dos axônios mielínicos; espessuras das bainhas de mielina e diâmetro dos axônios amielínicos. Os nervos regenerados no interior das próteses tubulares apresentaram diâmetros das fibras mielínicas com média de 5,12ñ1,67µm; média dos diâmetros dos axônios mielínicos de 4,08ñ1,52µm; média das espessuras das bainhas de mielina de 0,52ñ0,18µm; média dos diâmetros dos axônios amielínicos de 0,98ñ0,37µm. Os enxertos apresentaram os seguintes valores: média dos diâmetros das fibras mielínicas de 6,04ñ2,27µm; média dos diâmetros dos axônios mielínicos de 4,59ñ1,95µm; média das espessuras das bainhas de mielina de 0,72ñ0,23µm; média dos diâmetros dos axônios amielínios de 0,96ñ0,40µm. Estes resultados permitiram concluir que os procedimentos cirúrgicos utilizados, quando analisadas as fibras regeneradas no interior das próteses tubulares e dos auto-enxertos, näo apresentaram diferenças morfométricas significantes, decorridas 26 semanas de observaçäo pós-operatória

Tibial hemimelia: report on 37 new cases, clinical and genetic considerations.

We report on 37 patients belonging to different families, who have the tibial hemimelia-split hand/foot syndrome. Genetic aspects and phenotypic manifestations are compared with previous reports of tibial hemimelia. An attempt to clinical and genetical approach is suggested.

[Resistance of Biomphalaria schrammi of Arcos, Minas Gerais, Brazil, to infection with 2 strains of Schistosoma mansoni]. / Resistencia de Biomphalaria schrammi de Arcos, Minas Gerais, Brasil, a infecção com duas cepas de Schistosoma mansoni.

The descendants of planorbid snail Biomphalaria schrammi Crosse, 1864, collected in the region of Arcos, State of Minas Gerais, Brazil, were exposed to miracidia of two strains of Schistosoma mansoni: the "LE" strain from Belo Horizonte, Minas Gerais State and the "SJ" strain from São José dos Campos, State of São Paulo. Of the 172 snails exposed to miracidia of both strains, none were infected. On the other hand, 100 Biomphalaria glabrata snails of the control group showed infection rates of 88% ("LE" strain) and 40% ("SJ" strain). The mortality rates of B. schrammi and B. glabrata were 40% and 10%, respectively.

[A stock of infected snails for the mass breeding of cercariae and schistosomules]. / Criacão de caramujos infectados para obtencão em massa de cercãrias e esquistossômulos.

A routine to maintain infected snails Biomphalaria glabrata able to produce 1-2 million cercariae per week and a mean shedding of about 3,500 cercariae per snail was quantitatively described. To a monthly production of about 5.3 and 6.5 million cercariae during the years of 1982 and 1983 it was necessary to expose an average of 1,557 and 1,957 snails, respectively. The efficiency described was maintained by infecting 2,000 snails per month (infectivity index of about 60%). A maximal production of 6,000 cercariae/snail was obtained in the period between 56-70 days after the snail infection by miracidia. By this period, however, 90% of the infected snails were dead. In the summer of 1982-1983 it was observed an impairment on the daily cercarial harvests which was related to ambient temperature increase, and the presence of rotifers in the aquaria water. When the cercariae were transformed into schistosomula in vitro, a yield of 55% schistosomula was obtained, with 7% of tail contamination. Lyophilization of cercariae produced 50.9 +/- 63 g dry weight per 1,000 cercariae.