Lysine biosynthesis inMethanobacterium thermoautotrophicum is by the diaminopimelic acid pathway

Methanobacterium thermoautotrophicum, an archaebacterium, possesses the first and last enzymes of the diaminopimelic acid pathway for lysine biosynthesis, dihydrodipicolinate synthase, and diaminopimelate decarboxylase. It does not have saccharopine dehydrogenase, the last enzyme of the aminoadipate pathway for lysine biosynthesis. The dihydrodipicolinate synthase is inhibited but not repressed by lysine. We conclude that this microbe uses the diaminopimelate pathway for synthesis of lysine.Deceased.     

Ultrastructure of Sporulating Bacillus larvae in a Broth Medium

An electron microscopic study of sporulation of Bacillus larvae, a honeybee pathogen, in TMYGP broth (D. W. Dingman and D. P. Stahly, Appl. Environ. Microbiol. 46:860-869, 1983) was conducted. No parasporal structures were evident in the sporangial cytoplasm. The stages of sporulation were similar to those observed in other sporeformers. A rather unusual inner coat layer consisting of seven lamellae was apparent.     

Factor scoring models of the Pittsburgh Sleep Quality Index: a comparative confirmatory factor analysis

The Pittsburgh Sleep Quality Index (PSQI) is a rigorously validated questionnaire with extensive use in sleep assessment. Findings from numerous factor analytic studies of the PSQI have been interpreted to support a heterogeneous factor structure model for the test. Nevertheless, the literature continues to lack a focused evaluation of whether this heterogeneous factor structure is justified. A consideration of this issue led to a conclusion that a closer analysis of the PSQI’s factor structure was merited. To address this need a comparative confirmatory factor analysis for assessing the performance of the accepted factors models of the PSQI was conducted. A sample of university students (n = 418), age = 20.92 ± 1.81 years, BMI = 23.30 ± 2.57 kg/m² completed the multi-structured sleep survey at Jamia Millia Islamia, New Delhi, India. Seventeen putative factor structures (three 1-Factor, eight 2-Factor, and six 3-Factor) of the PSQI from the existing literature were selected for analysis. Fourteen models (82.35%) had almost similar values for model fit indices. Two models were misfits, and one model was a poor fit. The two misfit models incorporated gender and age as covariates. The third poor fit model was used to produce a unique path diagram, which made it distinct from the remaining 16 models. The overlapping values in the fit range of the model fit indices did not support the often projected heterogeneous factor structures of the PSQI for the vast majority of the models.     

The chemokine receptor CCR5 is not a necessary inflammatory mediator in kainic acid-induced hippocampal injury: evidence for a compensatory effect by increased CCR2 and CCR3

Chemokines and their receptors have been strongly implicated in the inflammatory process. However, their roles in excitotoxic brain injury are largely unknown. In this study we used C-C chemokine receptor 5 (CCR5) knockout (KO) mice to investigate the role of CCR5 in neurodegeneration induced by intranasal administration of the excitotoxin kainic acid (KA). Although KA treatment resulted in an increased CCR5 mRNA level in the hippocampi of wild-type mice, a CCR5 deficiency in KO mice did not affect either the clinical and pathological changes in vivo or the neuronal susceptibilities to KA insult in vitro. KA treatment stimulated mRNA expression of the monocyte chemoattractant protein-2 (MCP-2) in both the wild-type and KO mice. KA treatment did not affect mRNA levels for the macrophage inflammatory protein-1alpha (MIP-1alpha) or the regulated upon activation normal T cells expressed and secreted protein (RANTES) in either wild-type or CCR5 KO mice. CCR2 mRNA expression was undetectable in the hippocampi of wild-type mice regardless of KA treatment. In contrast, CCR5 KO mice showed CCR2 mRNA expression that was remarkably increased after KA treatment. KA treatment did not affect CCR3 mRNA expression in the wild-type mice, whereas KO mice showed both a higher basal level of CCR3 mRNA expression as well as a strong upregulation following KA treatment. These results indicate that CCR5 is not a necessary inflammatory mediator in KA induced neurodegeneration. The roles of CCR5 in excitotoxic injury in CCR5 deficient mice are compensated by increased CCR2 and CCR3 expression, which share the common MCP-2 ligand with CCR5.     

RANTES promotes growth and survival of human first-trimester forebrain astrocytes

We have examined the role of alpha and beta chemokines in the promotion of the ontogenetic development of the brain. RANTES was expressed preferentially in human fetal astrocytes in an age-dependent manner. Astrocytes from 5-week-old brains showed high proliferation and reduced survival, whereas 10-week-old astrocytes exhibited opposite effects. These effects were suppressed by anti-RANTES or anti-RANTES receptor antibodies and were enhanced by recombinant RANTES. RANTES induced tyrosine phosphorylation of several cellular proteins and nuclear translocation of STAT-1 in astrocytes. Interferon-gamma (IFN-gamma) was required for RANTES effects because RANTES induced IFN-gamma and only 10-week-old astrocytes expressed the IFN-gamma receptor. Blocking of IFN-gamma with antibody reversed the effects of RANTES, indicating that cytokine/chemokine networks are critically involved in brain development.     

Halobacterium volcanii spec. nov., a Dead Sea halobacterium with a moderate salt requirement

A halophilic bacterium was isolated from bottom sediment from the Dead Sea. The organism possessed the properties of the halobacteria, but differed from the known species in two important respects, 1) the cells were disc-shaped and often cupped when grown under optimum conditions, 2) the optimum requirements for sodium chloride was in the range 1.7–2.5 molar which is about half of that generally reported for the halobacteria. The organism was assigned to the genus Halobacterium and described as Halobacterium volcanii spec.nov. The optimum sodium chloride concentration for growth was close to that found in the Dead Sea. The tolerance for magnesium chloride was very high; the organism grew well in media containing magnesium chloride in the concentrations found in the Dead Sea. Halobacterium volcanii is therefore remarkably well fitted for life in the Dead Sea.     

Delipidated retroviruses as potential autologous therapeutic vaccines--a pilot experiment

This pilot experiment in a simian immunodeficiency virus (SIV) chronic infection model aimed at extending our previous findings that vaccination with delipidated SIV resulted in more potent and diversified antiviral responses (1). Macaques chronically infected with SIVmac239 treated with antiretroviral therapy (ART) were vaccinated with autologous delipidated virus via consecutive lymph node targeted immunizations-1, 1 and 10 mug of virus spaced monthly. Results showed all animals had lasting viral load reduction approaching 1 log compared to set-point, and disease delay. Delipidation may enhance processing/ presentation of viral antigen eliciting potent antiviral control even at such late infection stage.     

A novel nervous system-induced factor inducing immune responses in the spleen

This study relates to a novel mediator signaling between the nervous system and the spleen following an immune challenge. Using enzyme-linked immunospot and cell proliferation assays, we found that supernatants of cultured splenocytes prepared from subcutaneously trypanosome-inoculated rats and mice spleens obtained immediately after inoculation and added to naive cells significantly stimulate interferon-gamma production and cell proliferation compared to phosphate-buffered saline-inoculated animals. This action was abrogated by surgical denervation of the spleen. Using the fluorescent differential display technology, the gene involved in this process was identified and further cloned and its sequence was mapped to chromosome 14 (GenBank accession number: EU552928). Protein expression revealed approximately 15 kDa molecule with biological activities similar to the cultured supernatants of splenocytes obtained directly from parasite-inoculated animals. Antibodies raised against the protein blocked the activities of both the protein and the supernatant and also recognized a band in the active supernatant with the same molecular mass as the protein. Furthermore, the protein was able to reactivate experimentally immunosuppressed cells by regaining their ability to proliferate, suggesting that such a nervous system-induced immune system-released activating agent (ISRAA) may have a potential therapeutic benefit in immunocompromised situations and in further understanding the mechanism for innate immunity commencement and action.