Mechanism of Hyperventilation in Acute Cerebrovascular Accidents

Lumbar cerebrospinal fluid and arterial blood acid-base state were assessed in 19 patients within 24 hours of an acute cerebrovascular accident. Those with haemorrhage into the C.S.F. showed a lower C.S.F. pH and higher C.S.F. lactate than those without haemorrhage but the Pco₂, was similar in the two groups, suggesting that this greater C.S.F. acidity was not responsible for a greater degree of hyperventilation. In those without haemorrhage an inverse relation was found between C.S.F. pH and arterial Pco₂, suggesting that a non-chemical ventilatory drive—for example, due to central neurological damage—was responsible for the acid-base changes observed.     

Somatic embryogenesis in callus cultures of Rosa hybrida L. cv. Landora

Callus was initiated from immature leaf and stem segments of rose (Rosa hybrida cv. Landora) and subcultured every four weeks on a basal medium of half-strength Murashige & Skoog (1962) salts plus 30 g l^-1 sucrose (1/2 MS) and supplemented with 2.2 M BA, 5.4 M NAA and 2.2–9.0 M 2,4-D. Embryogenic callus and subsequently somatic embryos were obtained from 8-week-old callus culture on 1/2 MS+2.2 M BA+0.05 M NAA+0.3 M GA₃+200–800 mg l^-1 L-proline. Long-term cultures were established and maintained for up to 16 months by repeated subculture of embryogenic callus on L-proline deficient medium. About 12% of cotyledonary stage embryos taken from cultures cold-stored at 8±1°C for 4 days germinated on 1/2 MS+2.2 M BA+0.3 M GA₃+24.7 M adenine sulphate.Abbreviations BA benzyladenine - NAA -naphthaleneacetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - GA₃ gibberellic acid     

Target highlights in CASP13: Experimental target structures through the eyes of their authors

The functional and biological significance of selected CASP13 targets are described by the authors of the structures. The structural biologists discuss the most interesting structural features of the target proteins and assess whether these features were correctly reproduced in the predictions submitted to the CASP13 experiment.     

Localization of the human oestrogen receptor gene to chromosome 6q24----q27 by in situ hybridization

The oestrogen receptor gene (ER) was mapped by in situ hybridization. Using a human cDNA probe containing the coding sequence for the oestrogen receptor, the gene was localized to 6q24----q27.     

Structure-function mapping of a heptameric module in the nuclear pore complex

The nuclear pore complex (NPC) is a multiprotein assembly that serves as the sole mediator of nucleocytoplasmic exchange in eukaryotic cells. In this paper, we use an integrative approach to determine the structure of an essential component of the yeast NPC, the ~600-kD heptameric Nup84 complex, to a precision of ~1.5 nm. The configuration of the subunit structures was determined by satisfaction of spatial restraints derived from a diverse set of negative-stain electron microscopy and protein domain-mapping data. Phenotypic data were mapped onto the complex, allowing us to identify regions that stabilize the NPC's interaction with the nuclear envelope membrane and connect the complex to the rest of the NPC. Our data allow us to suggest how the Nup84 complex is assembled into the NPC and propose a scenario for the evolution of the Nup84 complex through a series of gene duplication and loss events. This work demonstrates that integrative approaches based on low-resolution data of sufficient quality can generate functionally informative structures at intermediate resolution.     

Biodegradation of chlorpyrifos by bacterial consortium isolated from agriculture soil

Organophosphorous pesticides are widely used in agriculture to control major insect pests. Chlorpyrifos is one of the major organophosphorous pesticides which is used to control insects including termites, beetles. The widespread use of these pesticides is hazardous to the environment and also toxic to mammals, thus it is essential to remove the same from the environment. From the chlorpyrifos contaminated soil nine morphologically different bacterial strains, one actinomycete and two fungal strains were isolated. Among those isolates four bacterial strains which were more efficient were developed as consortium. The four bacterial isolates namely Pseudomonas putida (NII 1117), Klebsiella sp., (NII 1118), Pseudomonas stutzeri (NII 1119), Pseudomonas aeruginosa (NII 1120) present in the consortia were identified on the basis of 16S rDNA analysis. The intracellular fractions of the consortium exhibited more organophosphorus hydrolase activity (0.171 ± 0.003 U/mL/min). The degradation studies were carried out at neutral pH and temperature 37°C with chlorpyrifos concentration 500 mg L⁻¹. LC-mass spectral analysis showed the presence of metabolites chlopyrifos-oxon and Diethylphosphorothioate. These results highlight an important potential use of this consortium for the cleanup of chlorpyrifos contaminated pesticide waste in the environment.     

Denaturation of HIV-1 protease (PR) monomer by acetic acid: mechanistic and trajectory insights from molecular dynamics simulations and NMR

Inside a living cell there can be a variety of interactions for any given protein, which serve to regulate denaturation and renaturation processes. Insights into some of them can be obtained by in vitro studies using various denaturing agents. In this study, all-atom MD simulations in explicit solvent and NMR relaxation studies were performed on HIV-1 Protease (PR) in 9 M acetic acid (AcOH) (the commonly used denaturant during PR preparation). Following previous reports that denaturation proceeds via dissociation of the dimer into monomers, unfolding of the monomer by acetic acid has been explicitly investigated here. Direct visualization of the denaturation process and evidence for the mechanism of denaturation have been presented. Our simulations reveal that the denaturation of the PR monomer is caused due to direct interaction between acetic acid molecules and PR. Autocorrelation of N-H vectors calculated from the simulations have revealed that the α-helix and the surrounding β-strands represent the sensitive regions of the PR that respond maximally to the change in the solvent environment around the PR and are prone to disruption by acetic acid. This disruption is caused due to increased penetration of the acetic acid molecules into the PR structure by formation of preferred tertiary contacts and hydrogen bonds between the PR and acetic acid molecules. Following the loss of these critical interactions, the PR follows a random and non-equilibrating path on the conformation landscape and cycles between different denatured extended and compact states.     

Genetic diversity of Plasmodium vivax in a hyperendemic area predominated by Plasmodium falciparum; a preliminary study

Understanding the genetic diversity, extent and distribution of variant forms of Plasmodium vivax parasites is crucial in the development of effective control measures and in Orissa, a hyperendemic state in the eastern part of India, the polymorphic nature of P. vivax isolates is largely lacking. The result of the study analyzing two highly polymorphic single copy genes for P. vivax circumsporozoite protein (pvcs) and P. vivax merozoite surface protein 3α (pvmsp3α) shows that the parasite population is highly heterogenous (33 distinct genotype from 35 isolates) in Orissa. However, the observation of the multiplicity of infection value of 1.34 and high frequency distribution of certain genotype with respect to individual marker (the VK247b allele with a frequency of 0.37; VK210e with 0.25 and VK210c with 0.14) suggests that the parasite population are likely to be under selective pressure and may either be due to preferential production of sporozoites carrying these variants in the available anopheline mosquito species of the state or selection of particular genotypes by host immune pressure. Moreover, although P. vivax in South-East Asia indicates an overall predominance of VK210 which is thought to be the best adapted variant of pvcs repeat type, the almost equal prevalence of both repeat type of pvcs; VK210 and VK247 in the present study is unexpected and needs further study for clarification.