Glycosylation of Pseudomonas aeruginosa strain Pa5196 type IV pilins with mycobacterium-like alpha-1,5-linked d-Araf oligosaccharides

Pseudomonas aeruginosa is a gram-negative bacterium that uses polar type IV pili for adherence to various materials and for rapid colonization of surfaces via twitching motility. Within the P. aeruginosa species, five distinct alleles encoding variants of the structural subunit PilA varying in amino acid sequence, length, and presence of posttranslational modifications have been identified. In this work, a combination of mass spectrometry and nuclear magnetic resonance spectroscopy was used to identify a novel glycan modification on the pilins of the group IV strain Pa5196. Group IV pilins continued to be modified in a lipopolysaccharide (wbpM) mutant of Pa5196, showing that, unlike group I strains, the pilins of group IV are not modified with the O-antigen unit of the background strain. Instead, the pilin glycan was determined to be an unusual homo-oligomer of alpha-1,5-linked d-arabinofuranose (d-Araf). This sugar is uncommon in prokaryotes, occurring mainly in the cell wall arabinogalactan and lipoarabinomannan (LAM) polymers of mycobacteria, including Mycobacterium tuberculosis and Mycobacterium leprae. Antibodies raised against M. tuberculosis LAM specifically identified the glycosylated pilins from Pa5196, confirming that the glycan is antigenically, as well as chemically, identical to those of Mycobacterium. P. aeruginosa Pa5196, a rapidly growing strain of low virulence that expresses large amounts of glycosylated type IV pilins on its surface, represents a genetically tractable model system for elucidation of alternate pathways for biosynthesis of d-Araf and its polymerization into mycobacterium-like alpha-1,5-linked oligosaccharides.     

Some behavioural effects of carbamazepine - comparison with haloperidol.

The experiments presented in this paper aimed to investigate the influence of atypical antiepileptic drug carbamazepine (CBZ, CAS 298-46-4) classified also as normothymic drug on spatial memory in Morris water maze test and anxiolytic effect in two-compartment exploratory test in rats. The study also investigated the probably occurring side effects (measuring cataleptic activity and motor coordination) following single and chronic administration of CBZ compared to haloperidol (HAL, CAS 52-86-8), a conventional antipsychotic. All the tests were carried out on male Wistar rats. CBZ 30 mg/kg was administered orally 60 min before the tests and HAL 0.15 mg/kg was administered orally 60 min before the tests. In the Morris test memory improvement only after chronic administration of CBZ on the 7 and 14 day of treatment was observed, whereas after 14 days of HAL treatment spatial memory impairment was noted. In the two-compartment exploratory test 30 mg/kg of CBZ had an anxiolytic effect after 7 and 14 days of treatment, whereas HAL did not show anxiolytic effect after single and chronic treatment. CBZ did not induce catalepsy after single as well as chronic administration. HAL evoked a strong cataleptic effect both after acute and chronic treatment. CBZ had no impact on motor coordination in the chimney test and HAL disturbed motor coordination in rats after single as well as chronic administration. CBZ may be an useful normothymic drug using in bipolar affective disorder treatment with co-occurred anxiety and cognitive deficits. The lack of significant side effects of CBZ may be an alternative way of treatment in comparison with older drugs, such as lithium carbonate.     

A novel cry2Ab gene from the indigenous isolate Bacillus thuringiensis subsp. kurstaki

A novel cry2Ab gene was cloned and sequenced from the indigenous isolate of Bacillus thuringiensis subsp. kurstaki. This gene was designated as cry2Ab25 and its sequence revealed an open reading frame of 1,902 bp encoding a 633 aa protein with calculated molecular mass of 70 kDa and pI value of 8.98. The amino acid sequence of the Cry2Ab25 protein was compared with previously known Cry2Ab toxins, and the phylogenetic relationships among them were determined. The deduced amino acid sequence of the Cry2Ab25 protein showed 99% homology to the known Cry2Ab proteins, except for Cry2Ab10 and Cry2Ab12 with 97% homology, and a variation in one amino acid residue in comparison with all known Cry2Ab proteins. The cry2Ab25 gene was expressed in Escherichia coli BL21(DE3) cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the Cry2Ab25 protein is about 70 kDa. The toxin expressed in BL21(DE3) exhibited high toxicity against Malacosoma neustria and Rhagoletis cerasi with 73% and 75% mortality after 5 days of treatment, respectively.     

Bridging structural biology and genomics: assessing protein interaction data with known complexes

Currently, there is a major effort to map protein-protein interactions on a genome-wide scale. The utility of the resulting interaction networks will depend on the reliability of the experimental methods and the coverage of the approaches. Known macromolecular complexes provide a defined and objective set of protein interactions with which to compare biochemical and genetic data for validation. Here, we show that a significant fraction of the protein-protein interactions in genome-wide datasets, as well as many of the individual interactions reported in the literature, are inconsistent with the known 3D structures of three recent complexes (RNA polymerase II, Arp2/3 and the proteasome). Furthermore, comparison among genome-wide datasets, and between them and a larger (but less well resolved) group of 174 complexes, also shows marked inconsistencies. Finally, individual interaction datasets, being inherently noisy, are best used when integrated together, and we show how simple Bayesian approaches can combine them, significantly decreasing error rate.     

Glutamate Inhibition of the Adrenergic-Stimulated Production of Melatonin in Rat Pineal Gland In Vitro

Abstract: The effect of l -glutamate on the adrenergic-stimulated release of melatonin in the rat pineal gland was examined using an in vitro perfusion system. l -Glutamate by itself had no effect on melatonin secretion whereas l -glutamate administered prior to (–)-isoproterenol (β-adrenergic agonist) and l -phenylephrine (α-adrenergic agonist) inhibited melatonin production by 42%. l -Glutamate did not inhibit melatonin secretion when glands were stimulated with (–)-isoproterenol alone. d -Glutamate, as well as the l -glutamate agonists kainate, N -methyl- d -aspartate, quisqualate, and trans -1-aminocyclopentane-1, 3-dicarboxylic acid, had no effect on the (–)-isoproterenol-and l -phenylephrine-stimulated secretion of melatonin, which suggests that the inhibitory effects of glutamate are not mediated via any of the known glutamate receptor subtypes. The possibility that l -glutamate may be converted to another neuroactive compound (GABA) prior to the addition of (–)-isoproterenol and l -phenylephrine is suggested by the observation that simultaneous administration of l -glutamate with (–)-isoproterenol and l -phenylephrine did not inhibit melatonin production.     

Use of Restored Riparian Habitat by the Endangered Least Bell's Vireo (Vireo bellii pusillus)

A primary objective of riparian restoration in California is the creation of habitat for endangered species. Four restoration sites in San Diego County were monitored between 1989 and 1993 and evaluated for their suitability as nesting habitat for Vireo bellii pusillus (Least Bell's Vireo), a state and federally endangered obligate riparian breeder. Vegetation structure at each site was quantified annually and compared to a model of canopy architecture derived from Least Bell's Vireo territories in natural habitat. Vireo use of restored habitat was documented through systematic surveys and nest monitoring. By 1993, only one site in its entirety met the habitat suitability criteria of the model, but portions of each site during all years did so. Differences between sites in the time required to develop suitable habitat—well-developed layered vegetation from the ground to under 8m in height)—were attributable largely to variation in annual rainfall. Vireos visited restoration sites to forage as early as the first growing season, but they did not establish territories or nest there until at least part of the site supported suitable habitat as determined from the model. Placement of territories and nests coincided with patches of dense vegetation characteristic of natural nesting areas. Occupation of restored sites was accelerated by the presence of adjacent mature riparian habitat, which afforded birds nest sites and/or foraging habitat lacking in the planted vegetation. Vireos nesting in restored habitat achieved success comparable to that of vireos nesting in surrounding natural habitat, and there was no evidence that productivity was reduced in created areas. These findings indicate that creating nesting habitat for this target species is feasible and suggest that the critical components of vireo nesting habitat have been captured in both the design and quantitative assessment of restoration sites.     

Evaluation of the interaction between proliferation,oxidant–antioxidant status,Wnt pathway,and apoptosis in zebrafish embryos exposed to silver nanoparticles used in textile industry

Antimicrobial textile products are developing rapidly as an important part of functional textiles. Silver nanoparticles (AgNPs) are nanotechnology products with antimicrobial properties. However, exposure to nanoparticles in daily life is an important issue for public health, still being updated. Aim was to evaluate the effects of AgNPs on the development of zebrafish embryos focusing on Wnt pathway, proliferation, oxidant–antioxidant status, and apoptosis. The expressions of ccnd1 and gsk3β were determined by RT‐PCR, whereas β‐catenin and proliferative cell antigen (PCNA) expressions were determined immunohistochemically. Lipid peroxidation, superoxide dismutase, and glutathione‐S‐transferase activities were determined spectrophotometrically. Apoptosis was determined using acridine orange staining. Oxidant status, apoptosis, immunohistochemical PCNA, and β catenin staining increased, whereas ccnd1 and antioxidant enzyme activities decreased in AgNPs‐exposed embryos in a dose‐dependent manner. Our results indicate the interaction of possible mechanisms that may be responsible for the toxic effects of AgNPs in zebrafish embryos.     

Conservation genomics reveals multiple evolutionary units within Bell’s Vireo (<Emphasis Type="Italic">Vireo bellii</Emphasis>)

The Bell’s Vireo (Vireo bellii) is a widespread North American species of bird that has declined since the mid-1960s primarily due to habitat modification. Throughout its range, Bell’s Vireo populations are regulated under varying degrees of protection; however, the species has never been characterized genetically. Therefore, the current taxonomy used to guide management decisions may misrepresent the true evolutionary history for the species. We sequenced 86 individuals for ND2 and genotyped 48 individuals for genome-wide SNPs to identify distinct lineages within Bell’s Vireo. Phylogenetic analyses uncovered two distinct clades that are separated in the arid southwestern United States, near the border of the Chihuahuan and Sonoran Deserts. These clades diverged from each other approximately 1.11–2.04 mya. The timing of diversification, geographic location, and niche modeling of the east/west divergence suggest vicariance as a mode of diversification for these two lineages. Analyses of the SNP dataset provided additional resolution and indicated the Least Bell’s Vireo populations are a distinct evolutionary lineage. Our genetic evidence, together with information from morphology and behavior, suggests that the Bell’s Vireo complex involves two species, each containing two separate subspecies. This new information has implications for the federal, state and other listing status of Bell’s Vireo throughout its range.     

The protective effects of omega-3 fatty acids against MK-801-induced neurotoxicity in prefrontal cortex of rat

The aims of this study are to investigate the contribution effect of oxidative stress in MK-801-induced experimental psychosis model, and to show that prevention of oxidative stress may improve prognosis. Because oxidative damage has been suggested in the neuropathophysiology of schizophrenia, the possible protecting agents against lipid peroxidation are potential target for the studies in this field. For this purpose, Wistar Albino rats were divided into three groups: the first group was used as control, MK-801 was given to the rats in the second group and MK-801+omega-3 essential fatty acids (EFA) was given to the third group. MK-801 was given intraperitoneally at the dose of 0.5mg/(kgday) once a day for 5 days in experimental psychosis group. In the second group, 0.8g/(kgday), omega-3 FA (eicosapentaenoic acid, 18%, docosahexaenoic acid, 12%) was given to the rats while exposed MK-801. In control group, saline was given intraperitoneally at the same time. After 7 days, rats were killed by decapitation. Prefrontal brain area was removed for histological and biochemical analyses. As a result, malondialdehyde (MDA), as an indicator of lipid peroxidation, protein carbonyl (PC), as an indicator of protein oxidation, nitric oxide (NO) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities as antioxidant enzymes, and xanthine oxidase (XO) and adenosine deaminase (AD) activities as an indicator of DNA oxidation was found to be increased significantly in prefrontal cortex (PFC) of MK-801 group (P<0.0001) compared to control group. In omega-3 FA treated rats, prefrontal tissue MDA, PC and NO levels as well as SOD, GSH-Px, XO, and AD enzyme activities were significantly decreased when compared to MK-801 groups (P<0.0001) whereas catalase (CAT) enzyme activity was not changed. Moreover, in the light of microscopic examination of MK-801 groups, a great number of apoptotic cells were observed. omega-3 FA supplementation decreased the apoptotic cell count in PFC. The results of this study revealed that oxidative stress and apoptotic changes in PFC may play an important role in the pathogenesis of MK-801-induced neuronal toxicity. This experimental study also provides some evidences for the protective effects of omega-3 FA on MK-801-induced changes in PFC of rats.