An acidic phospholipase A₂ with antibacterial activity from Porthidium nasutum snake venom

Snake venoms are complex mixtures of proteins among which both basic and acidic phospholipases A₂ (PLA₂s) can be found. Basic PLA₂s are usually responsible for major toxic effects induced by snake venoms, while acidic PLA₂s tend to have a lower toxicity. A novel PLA₂, here named PnPLA₂, was purified from the venom of Porthidium nasutum by means of RP-HPLC on a C18 column. PnPLA₂ is an acidic protein with a pI of 4.6, which migrates as a single band under both non-reducing and reducing conditions in SDS-PAGE. PnPLA₂ had a molecular mass of 15,802.6 Da, determined by ESI-MS. Three tryptic peptides of this protein were characterized by HPLC-nESI-MS/MS, and N-terminal sequencing by direct Edman degradation showing homology to other acidic PLA₂s from viperid venoms. PnPLA₂ displayed indirect hemolytic activity in agarose erythrocyte-egg yolk gels and bactericidal activity against Staphylococcus aureus in a dose-dependent manner, with a MIC and MBC of 32 μg/mL. In addition, PnPLA₂ showed a potent inhibitory effect on platelet aggregation with doses up to 40 μg/mL. This acidic PLA₂, in contrast to basic enzymes isolated from other viperid snake venoms, was not cytotoxic to murine skeletal muscle myoblasts C₂C₁₂. This is the first report on a bactericidal protein of Porthidium nasutum venom.     

All pyruvylated galactose in Schizosaccharomyces pombe N-glycans is present in the terminal disaccharide, 4, 6-O-[(R)-(1- carboxyethylidine)]-Galbeta1,3Galalpha1-

The large N-linked oligosaccharides released from Schizosaccharomyces pombe by endo-beta-N-acetylglucosaminidase H were examined to determine how the negatively chargedpyruvylated galactoses present (Gemmill,T.R., and Trimble,R.B., 1996, J. Biol. Chem ., 271, 25945-25949) were attached to the oligosaccharide chains. Binding of biotinylated human serum amyloid P and peanut agglutinin to native and depyruvylated S.pombe glycoproteins, respectively, indicated that the pyruvylated epitope was likely to be in the beta configuration. Examination by high- field 1H NMR of whole glycans and a disaccharide fragment released from them on partial acid hydrolysis showed that the pyruvylated galactose species was in fact beta1,3-linked to a second galactose, and this occurred an average of five to six times on nominal Gal57Man64GlcNAc N- glycans. The pyruvate-2,(4,6)Gal-beta1,3Gal epitope is chemically similar to acetaldehyde-Galbeta1,3Gal groups found on the glycoproteins from Paramyxovirus-infected bovine kidney cells (Prehm, P., Scheid,A. and Choppin,P.W. ,1979, J. Biol. Chem ., 254, 9669-9677). The 1:1 stoichiometry between pyruvate and beta-linked galactose in these S.pombe glycans indicates that either pyruvate addition to terminal beta1,3Gal is highly efficient or that pyruvylated Gal is transferred en bloc to alpha1,2-linked Gal residues in theN-linked chains. In contradiction to many galactomannan-producing fungi, which add substantial amounts of Gal in the furanose form to their glycoproteins, all detectable Gal in the large S.pombe galactomannans is in the pyranose form, as found in higher eukaryotes. The current work shows that the S.pombe outer chain structure is a poly-alpha1,6Man backbone 2- O-substituted with either Gal or the pyruvylated galactobiose and contains little alpha1,2-linked or 2-O-substituted Man. This is in contrast to the S. cerevisiae outer chain, which is poly-alpha1,6Man substituted with alpha1,2-linked Man sidechains (Ballou,C.E. ,1990, Methods Enzymol , 185, 440-470).      

Polychaetes of the mangrove-fouling community at the Colombian Archipelago of San Andres and Old Providence,Western Caribbean

This study records the polychaetes found on the submerged roots of Rhizophora mangl on San Andres and Providence Islands, ColombianCaribbean. Sampling was done in 1998 during the rainy (July) and dry(November) seasons; each season, 17 roots were collected in threedifferent stations with different kinds of human impact, two in San Andresand one in Providence. At the same time temperature, salinity anddissolved oxygen were measured in situ. Aromatic hydrocarbons weremeasured in the laboratory. The polychaetes were removed from the rootsand identified. The available root area for the organisms was alsomeasured.Five genera and 11 species were newly recorded for the ColombianCaribbean. The most abundant families were Terebellidae in Old ProvidenceMc Bean Lagoon, Syllidae in Honda Bay and Nereididae in Hooker Bayon the San Andres Island. Thelepus `setosus' (Terebellidae) and Amblyosyllis sp. (Syllidae) were highly abundant in less polluted samplingstations such as Old Providence Mc Bean Lagoon and Honda Bay. On theother hand, Neanthes `succinea' (Nereididae) were abundant inHooker Bay which was the most polluted station. Salinity seemed to be the mostimportant parameter for the polychaete populations. The populations ofpolychaetes, as a total group, seemed to be related to the root areaavailable on both islands, independent of the season. However, during therainy season, the populations were independent of root area availability,while during the dry season, the populations were dependent on it.     

Circulating Glycated Albumin and Glomerular Anionic Charges

Aiming to discern the mechanisms by which circulating glycated albumin alters the glomerular filtration properties that lead to glomerular dysfunction in diabetes, the authors studied the distribution and densities of anionic charges through the rat glomerular wall upon intravascular infusion of Amadori products, as well as in various conditions of increased glomerular permselectivity. Polylysine-gold was used as the probe to reveal the anionic charges. The study was carried on renal tissue sections of bovine serum albumin (BSA)- and glycated BSA–injected, normoglycemic animals. Results were generated through morphometrical evaluations of the gold labeling. Changes in glomerular anionic distribution were corroborated on renal tissue sections of short- and long-term diabetic rats and of normal newborn rats, situations known for abnormal glomerular filtration. Altered renal function in these conditions was clearly associated with changes in glomerular anionic charges. On the other hand, the infusion of glycated albumin in the circulation of normal rats, though altering glomerular filtration properties, did not modify the distribution and density of the polylysine-gold labeling through the glomerular basement membrane. Thus, anionic charges seem not to be the factor involved in the early changes of glomerular permeability induced by circulating glycated albumin.     

Arbuscular mycorrhizal fungi in the growth and extraction of trace elements by Chrysopogon zizanioides (vetiver) in a substrate containing coal mine wastes

Vetiver (Chrysopogon zizanioides) is a fast-growing, high biomass producing plant employed for environmental rehabilitation. The study evaluated the effects of arbuscular mycorrhizal fungi (AMF) on the growth and trace element phytoextracting capabilities of vetiver in a substrate containing coalmine wastes in Southern Brazil. AMF included Acaulospora colombiana, Acaulospora morrowiae, Acaulospora scrobiculata, Dentiscutata heterogama, Gigaspora margarita, and Rhizophagus clarus. Among those, A. colombiana, G. margarita, and R. clarus promoted higher growth. AMF stimulated average increments in the accumulated P of 82% (roots), 194% (shoots first harvest—90 days) and 300% (shoots second harvest—165 days) and affected the phytoextraction of trace elements by vetiver, with larger concentrations in the roots. Plants inoculated with A. colombiana, A. morrowiae, and A. scrobiculata, in addition to the control, presented the highest levels of Cu and Zn in the roots. Overall, G. margarita stimulated the highest production of biomass, and, therefore, showed the most significant levels of trace elements in the plants. This work shows the benefits of certain AMF (especially A. morrowiae, G. margarita, and R. clarus) for the production of biomass and P uptake by vetiver, demonstrating the potential of those species for the rehabilitation of coal-mine-degraded soils.     

Synthesis, structure and biological activities of cobalt(II) and zinc(II) coordination compounds with 2-benzimidazole derivatives

In this work we present the synthesis, structural and spectroscopic characterisation of a series of cobalt(II) and zinc(II) coordination compounds with benzimidazole (bz) and its 2-benzimidazole derivatives: 2-aminobenzimidazole (2ab), albendazole (abz) and tris(2-benzimidazolylmethyl)amine (ntb). The compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus, Micrococcus luteus, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli and Proteus vulgaris. Their cytotoxic activity was also evaluated using human cancer lines, HeLa, HCT-15 and SKLU-1. The halide tetrahedral compounds [Co(bz)₂Br₂] 3, [Zn(2ab)₂Cl₂] · 0.5H₂O 11, [Co(abz)Cl₂(H₂O)] · 3H₂O 14, [Co(abz)Br₂(H₂O)] 15, [Zn(abz)Cl₂(H₂O)] · 3H₂O 17 and [Zn(abz)Br₂(H₂O)] · H₂O 18 displayed similar minimal inhibition concentration (MIC) values against Micrococcus luteus and Escherichia coli, comparable to those of amoxicillin and chloramphenicol. Additionally, 11 showed a wide range of activity towards Gram(+) and Gram(−) microorganisms. The tetradentate ntb and its trigonal bipyramidal cobalt(II) and zinc(II) compounds were active, regardless of the anion present in the complex. Compound [Co(abz)Cl₂(H₂O)] · 3H₂O 14 showed promising activity in HeLa cells, while [Co(ntb)Br]Br · H₂O 21 inhibited Hela and HCT-15 cell lines.     

Differences in telomere length between homologous chromosomes in humans

Telomeres are important structures for DNA replication and chromosome stability during cell growth. Telomere length has been correlated with the division potential of human cells and has been found to decrease with age in healthy individuals. Nevertheless, telomere lengths within the same cell are heterogeneous and certain chromosome arms typically have either short or long telomeres. Both the origin and the physiological consequences of this heterogeneity in telomere length remain unknown. In this study we used quantitative telomeric FISH combined with a method to identify the parental origin of chromosomes to show that significant differences in relative telomere intensities are frequently observed between chromosomal homologs in short-term stimulated cultures of peripheral blood lymphocytes. These differences appear to be stable for at least 4 months in vivo, but disappear after prolonged proliferation in vitro. The telomere length differences are also stable during in vitro growth of telomerase-negative fibroblast cells but can be abolished by exogenous telomerase expression in these cells. These findings suggest the existence of a mechanism maintaining differences in telomere length between chromosome homologs that is independent of telomere length itself.     

Methods for the differential integrative omic analysis of plasma from a transgenic disease animal model

Multitiered quantitative analysis of biological systems is rapidly becoming the desired approach to study hierarchical functional interactions between proteins and metabolites. We describe here a novel systematic approach to analyze organisms with complex metabolic regulatory networks. By using precise analytical methods to measure biochemical constituents and their relative abundance in whole plasma of transgenic ApoE*3-Leiden mice and an isogenic wild-type control group, simultaneous snapshots of metabolic and protein states were obtained. Novel data processing and multivariate analysis tools such as Impurity Resolution Software (IMPRESS) and Windows-based linear fit program (WINLIN) were used to compare protein and metabolic profiles in parallel. Canonical correlations of the resulting data show quantitative relationships between heterogeneous components in the TG animals. These results, obtained solely from whole plasma analysis allowed us, in a rapid manner, to corroborate previous findings as well as find new events pertaining to dominant and peripheral events in lipoprotein metabolism of a genetically modified mammalian organism in relation to ApoE3, a key mediator of lipoprotein metabolism.