Structural characterisation of a highly branched exopolysaccharide produced by Lactobacillus delbrueckii subsp. bulgaricus NCFB2074

Lactobacillus delbrueckii subsp. bulgaricus NCFB2074 when grown in skimmed milk secretes a highly branched exopolysaccharide. The exopolysaccharide has a heptasaccharide repeat unit and is composed of glucose and galactose in the molar ratio 3:4. Using chemical techniques and 1D and 2D NMR spectroscopy the polysaccharide has been shown to possess the following repeat unit structure: [carbohydrate structure: see text].     

The structure of echovirus type 12 bound to a two-domain fragment of its cellular attachment protein decay-accelerating factor (CD 55)

Echovirus type 12 (EV12), an Enterovirus of the Picornaviridae family, uses the complement regulator decay-accelerating factor (DAF, CD55) as a cellular receptor. We have calculated a three-dimensional reconstruction of EV12 bound to a fragment of DAF consisting of short consensus repeat domains 3 and 4 from cryo-negative stain electron microscopy data (EMD code 1057). This shows that, as for an earlier reconstruction of the related echovirus type 7 bound to DAF, attachment is not within the viral canyon but occurs close to the 2-fold symmetry axes. Despite this general similarity our reconstruction reveals a receptor interaction that is quite different from that observed for EV7. Fitting of the crystallographic co-ordinates for DAF(34) and EV11 into the reconstruction shows a close agreement between the crystal structure of the receptor fragment and the density for the virus-bound receptor, allowing unambiguous positioning of the receptor with respect to the virion (PDB code 1UPN). Our finding that the mode of virus-receptor interaction in EV12 is distinct from that seen for EV7 raises interesting questions regarding the evolution and biological significance of the DAF binding phenotype in these viruses.     

Nonmyeloablative bone marrow transplantation of BXSB lupus mice using fully matched allogeneic donor cells from green fluorescent protein transgenic mice

Male BXSB mice, a mouse model of systemic lupus erythematosus, were given bone marrow transplants (BMT) at 20 wk of age using MHC-matched donor cells and nonmyeloablative conditioning (550 cGy irradiation). Transplanted mice and irradiation controls were followed for a period of 20 wk. Mice transgenic for green fluorescent protein were used as donors to allow tracking of donor cells and a determination of chimerism. Radiation controls had reduced renal pathology at 10 wk posttransplant, but not at 20 wk compared with untreated mice, while nonmyeloablative BMT mice had significantly reduced pathology at both time intervals. The monocytosis characteristic of older BXSB mice was also reduced by BMT, but the treatment did not prevent production of Ab to dsDNA. A stable chimerism of 24-40% donor CD45-positive cells was achieved in spleen and bone marrow, and there was no evidence of clinical graft vs host disease. Donor cells were detected in most recipient organs, notably the thymus and renal glomeruli. The results suggest that complete depletion of mature lymphocytes or of progenitor stem cells is not required to control lupus nephritis in BXSB mice.     

Enhanced cardiovascular function and energy level by a novel chromium (III)-supplement

The impetus for the novel Energy Formula (EF) which combines the niacin-bound chromium (III) (0.45%) (NBC), standardized extract of Withania somnifera extracts (10.71%), caffeine (22.76%), D-ribose (10.71%) and selected amino acids such as phenylalanine, taurine and glutamine (55.37%) was based on the knowledge of the cardioprotective potentials of the Withania somnifera extract, caffeine and D-ribose as well as their abilities to increase energy levels and the abilities of amino acids to increase the muscle mass and energy levels. The effect of oral supplementation of EF on the safety, myocardial energy levels and cardioprotective ability were investigated in an ischemic-reperfused myocardium model in both male and female Sprague-Dawley rats over 90 days trial period. At the completion of 90 days, the EF-treated male and female rats gained 9.4% and 3.1% less body weights, respectively, as compared to their corresponding control groups. No significant difference was found in the levels of lipid peroxidation and activities of hepatic Aspartate transaminase, Alanine transaminase and Alkaline phosphatase in EF treatment when compared with control animals. The male and female rat hearts were subjected to 30 min of global ischemia followed by 2 h of reperfusion at 30 and 90 days of EF treatment. Cardiovascular functions including heart rate, coronary flow, aortic flow, dp/dt(max), left ventricular developed pressure (LVDP) and infarct size were monitored. The levels of myocardial adenosine triphosphate (ATP), creatine phosphate (CP), phospho-adenosine monophosphate kinase (p-AMPK) levels, were analyzed at the end of 30 and 90 days of treatment. Significant improvement was observed in all parameters in the EF treatment groups as compared to their corresponding controls. Thus the niacin-bound chromium (III) based energy formula is safe and effective supplement to boost energy levels and cardioprotection.     

High-dose chromium(III) supplementation has no effects on body mass and composition while altering plasma hormone and triglycerides concentrations

Chromium is generally believed to be an essential element and is often claimed to have value as a weight loss or muscle building agent. Recent studies in humans and rats have failed to demonstrate effects on body composition, although recent studies with pharmacological doses of the cation [Cr(III)₃O(O₂CCH₂CH₃)6(H₂O)₃]⁺ (or Cr3) (≤1 mg Cr/kg body mass) in rats have noted a trend toward body mass loss and fat mass loss. Thus, the effects of large gavage doses of Cr3 (1–10 mg Cr/kg) on body mass, organ mass, food intake, and blood plasma variables (insulin, glucose, leptin, cholesterol, and triglycerides) were examined over a 10-wk period using male Sprague-Dawley rats. No effects on body composition were noted, although Cr3 administration lowered (p<0.05) plasma insulin, leptin, and triglycerides concentrations. As Cr3 is absorbed greater than 10-fold better than commercially available nutritional supplements, the lack of an effect of the Cr(III) compound at these levels of administration clearly indicates that Cr(III) supplements do not have an effect on body composition at any reasonable dosage.     

The full-length clone of cucumber green mottle mosaic virus and its application as an expression system for Hepatitis B surface antigen

A cucumber green mosaic mottle virus (CGMMV) full-length clone was developed for the expression of Hepatitis B surface antigen (HBsAg). The expression of the surface displayed HBsAg by the chimeric virus was confirmed through a double antibody sandwich ELISA. Assessment of the coat protein composition of the chimeric virus particles by SDS-PAGE analysis showed that 50% of the coat proteins were fused to the HBsAg. Biological activity of the expressed HBsAg was assessed through the stimulation of in vitro antibody production by cultured peripheral blood mononuclear cells (PBMC). PBMC that were cultured in the presence of the chimeric virus showed up to an approximately three-fold increase in the level of anti HBsAg immunoglobulin thus suggesting the possible use of this new chimeric virus as an effective Hepatitis B vaccine.     

Population genetic structure of the dengue mosquito Aedes aegypti in Venezuela

The mosquito Aedes aegypti is the main vector of dengue in Venezuela. The genetic structure of this vector was investigated in 24 samples collected from eight geographic regions separated by up to 1160 km. We examined the distribution of a 359-basepair region of the NADH dehydrogenase subunit 4 mitochondrial gene among 1144 Ae. aegypti from eight collections. This gene was amplified by the polymerase chain reaction and tested for variation using single strand conformation polymorphism analysis. Seven haplotypes were detected throughout Venezuela and these were sorted into two clades. Significant differentiation was detected among collections and these were genetically isolated by distance.     

Antibacterial Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff bases derived from fluorobenzaldehyde and triazoles

Antibacterial Schiff bases derived from 1,2,4-triazoles as well as their metal complexes incorporating cobalt(II), nickel(II), copper(II) and zinc(II) have been synthesized and characterized. Physico-chemical studies suggest that an octahedral geometry for the cobalt(II), nickel(II) and zinc(II)and square-planer geometry for the copper(II) complexes. These complexes have been screened for antibacterial activity against three Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis) and two Gram-negative (Salmonella typhi and Pseudomonas aeruginosa) bacterial strains, and results compared with the activity of the free ligands. The metal complexes were found to be more potent against one or more bacterial strains than the free ligands.     

The role of leptin in innate and adaptive immune responses

Leptin is produced primarily by adipocytes and functions in a feedback loop regulating body weight. Leptin deficiency results in severe obesity and a variety of endocrine abnormalities in animals and humans. Several studies indicated that leptin plays an important role in immune responses. It exerts protective anti-inflammatory effects in models of acute inflammation and during activation of innate immune responses. In contrast, leptin stimulates T lymphocyte responses, thus having rather a proinflammatory role in experimental models of autoimmune diseases. Clinical studies have so far yielded inconsistent results, suggesting a rather complex role for leptin in immune-mediated inflammatory conditions in humans.     

Paramyxean–microsporidian co-infection in amphipods: Is the consensus that Microsporidia can feminise their hosts presumptive?

The current consensus is that Microsporidia belong to a select group of parasites capable of causing both intersexuality and complete sex reversal in their hosts. Indeed, species such as Nosema granulosis and Dictyocoela duebenum, which infect amphipod crustaceans, are regularly referred to as 'feminising microsporidians'. This categorisation is based on a combination of findings: that these species are vertically transmitted and occur at a high prevalence of infection in intersex and female amphipods, that infected amphipod populations are female-biased, and that infected females have significantly female-biased broods with no concurrent increase in mortality. In this study, we report on a population of the amphipod Echinogammarus marinus presenting both female bias and high levels of intersexuality, which are infected with D. deubenum. In keeping with its feminising classification, infection is prevalent in animals presenting female and intersex phenotypes. However, a further screen revealed the presence of a previously unknown paramyxean parasite related to organisms of the genus Marteilia, a group known to cause catastrophic sexual dysfunction in bivalves. We found that the paramyxean parasite was also vertically transmitted, with infections being more prevalent in females and intersex animals. Critically, every animal infected with D. deubenum was also co-infected with the paramyxean, with few animals presenting an independent paramyxean infection. In contrast, co-infection of E. marinus with a paramyxean and the non-feminising microsporidian Dictyocoela berillonum rarely occurred. These observations raise a new hypothesis, namely, that D. duebenum and other feminising microsporidians are not actually capable of host feminisation but instead 'hitch-hike' together with a feminising paramyxean parasite.