A Heterologous Multiepitope DNA Prime/Recombinant Protein Boost Immunisation Strategy for the Development of an Antiserum against Micrurus corallinus (Coral Snake) Venom

BackgroundEnvenoming by coral snakes (Elapidae: Micrurus), although not abundant, represent a serious health threat in the Americas, especially because antivenoms are scarce. The development of adequate amounts of antielapidic serum for the treatment of accidents caused by snakes like Micrurus corallinus is a challenging task due to characteristics such as low venom yield, fossorial habit, relatively small sizes and ophiophagous diet. These features make it difficult to capture and keep these snakes in captivity for venom collection. Furthermore, there are reports of antivenom scarcity in USA, leading to an increase in morbidity and mortality, with patients needing to be intubated and ventilated while the toxin wears off. The development of an alternative method for the production of an antielapidic serum, with no need for snake collection and maintenance in captivity, would be a plausible solution for the antielapidic serum shortage.ConclusionHere we describe that the genetic immunisation with a synthetic multiepitope gene followed by booster doses with recombinant protein is a promising approach to develop an alternative antielapidic serum against M. corallinus venom without the need of collection and the very challenging maintenance of these snakes in captivity.     

Eggshell Bacterial Load Is Related to Antimicrobial Properties of Feathers Lining Barn Swallow Nests

The use of feathers to line bird’s nests has traditionally been interpreted as having a thermoregulatory function. Feather-degrading bacteria growing on feathers lining nests may have antimicrobial properties, which may provide an additional benefit to lining nests with feathers. We test the hypothesis that the production of antimicrobial substances by feather bacteria affects the microbiological environment of the nest, and therefore the bacterial density on eggshells and, indirectly, hatching success. These effects would be expected to differ between nests lined with pigmented and white feathers, because bacteria grow differently on feathers of different colors. We experimentally manipulated the composition of pigmented and unpigmented feathers in nests of the barn swallow (Hirundo rustica) and studied the antimicrobial properties against the keratin-degrading bacterium Bacillus licheniformis of bacteria isolated from feathers of each color. Analyzed feathers were collected at the end of the incubation period, and antimicrobial activity was defined as the proportion of bacteria from the feathers that produce antibacterial substances effective against B. licheniformis. Our experimental manipulation affected antimicrobial activity, which was higher in nests with only white feathers at the beginning of incubation. Moreover, white feathers showed higher antimicrobial activity than black ones. Interestingly, antimicrobial activity in feathers of one of the colors correlated negatively with bacterial density on feather of the opposite color. Finally, antimicrobial activity of white feathers was negatively related to eggshell bacterial load. These results suggest that antimicrobial properties of feathers in general and of white feathers in particular affect the bacterial environment in nests. This environment in turn affects the bacterial load on eggshells, which may affect hatching success.     

Prevalence of the Helicobacter pylori babA2 gene and correlation with the degree of gastritis in infected Slovenian children

The aims of our study were to determine the prevalence of the babA2 gene within Helicobacter pylori strains circulating in the Slovenian pediatric population, to further clarify its significance in causing inflammation of gastric mucosa in children and to verify whether cagA, vacA, iceA and babA genes work independently or synergistically in causing gastritis. A total of 163 H. pylori isolates obtained from the same number of children were tested for the presence of cagA, vacA and iceA genes using previously established methods, while the babA2 gene was determined using novel polymerase chain reaction assay targeting a 139-bp fragment of the central region of babA2. The babA2 gene was detected in 47.9 % of H. pylori samples. The presence of the babA2 gene was strongly associated with cagA, vacA s1 and vacA m1 genotype. The babA2 status correlated positively with bacterial density score, activity of inflammation and chronic inflammation of gastric mucosa. No significant correlation was found between the babA2 status and the presence of atrophy or intestinal metaplasia. In addition, the activity of gastric inflammation and density score were significantly associated with the coexpression of the cagA, vacA s1, vacA m1 and babA2 genes. The study, which included the largest number of pediatric H. pylori samples to date, confirmed that babA2 gene plays an important role in the pathogenesis of H. pylori gastritis in children. Furthermore, our results suggest that babA2, cagA and vacA s1 and m1 gene products may work synergistically in worsening the inflammation of gastric mucosa.     

The antimalarial activity of Ru–chloroquine complexes against resistant Plasmodium falciparum is related to lipophilicity, basicity, and heme aggregation inhibition ability near water/n-octanol interfaces

We have measured water/n-octanol partition coefficients, pK _a values, heme binding constants, and heme aggregation inhibition activity of a series of ruthenium–π-arene–chloroquine (CQ) complexes recently reported to be active against CQ-resistant strains of Plasmodium falciparum. Measurements of heme aggregation inhibition activity of the metal complexes near water/n-octanol interfaces qualitatively predict their superior antiplasmodial action against resistant parasites, in relation to CQ; we conclude that this modified method may be a better predictor of antimalarial potency than standard tests in aqueous acidic buffer. Some interesting tendencies emerge from our data, indicating that the antiplasmodial activity is related to a balance of effects associated with the lipophilicity, basicity, and structural details of the compounds studied. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Stimulus-dependent control of inositol 1,4,5-trisphosphate-induced Ca(2+) oscillation frequency by the endoplasmic reticulum Ca(2+)-ATPase

In many cell types, receptor stimulation evokes cytosolic calcium oscillations with a frequency that depends on agonist dose. Previous studies demonstrated controversial effects of changing the activity of the endoplasmic reticulum Ca(2+)-ATPase upon the frequency of oscillations. By numerical simulations, we found that the model of De Young and Keizer (J. Keizer and G.W. De Young, 1994, J. Theor. Biol. 166: 431-442), unlike other models, can explain the observed discrepancies, assuming that the different experiments were performed at different stimulus levels. According to model predictions, partial inhibition of internal calcium pumps is expected to increase frequency at low stimulus strength and should have an opposite effect at strong stimuli. Similar results were obtained using an analytical estimation of oscillation period, based on calcium-dependent channel activation and inactivation. In experiments on HeLa cells, 4 nM thapsigargin increased the frequency of calcium oscillations induced by 1 and 2.5 microM histamine but had no effect on supramaximally stimulated cells. In HEp-2 cells, 2 nM thapsigargin slowed down the rapid, ATP-induced oscillations. Our results suggest that in the investigated cell types, the De Young-Keizer model based on inositol 1,4,5-trisphosphate-dependent calcium-induced calcium release can properly describe intracellular calcium oscillations.     

Receptor-like properties of the 26 kDa transmembrane form of TNF

Most members of the TNF family of proteins exist as transmembrane proteins with relatively long intracellular domains, and a number of them are involved in the ill-defined phenomenon of "reverse signaling". We have identified a putative nuclear localization signal in the cytoplasmic domain of TNF which proved to be functional in two assays. Western analysis identified an approximately 10 kDa peptide corresponding to the transmembrane and cytoplasmic domains of TNF after the proteolytic liberation of the 17 kDa, soluble form of TNF. This 10 kDa peptide was enriched in internal membranes and nuclear fractions of disrupted cells. Immune electron-microscopic studies proved its localization in transport vesicles and the nucleus. The nuclear transport of the intracellular segment of TNF resembles the signaling process through the Notch-type of receptors. Indeed, the presence of the 10 kDa peptide seems to influence the expression of another inflammatory cytokine, interleukin-1 beta. These findings suggest that the transmembrane form of TNF has receptor-like properties and its interaction with the receptors initiates a bidirectional signaling.     

Effects of putative galanin antagonists M35 and C7 on rat exocrine pancreas.

Galanin is a neuropeptide having a wide range of biological actions. Recently selective galanin receptor antagonists such as M35 [galanin(1-12)-Pro-bradykinin(2-9)-amide] and C7 [galanin(1-12)-Pro-spantide-amide] have been described. These antagonists have blocked the actions of galanin on flexor reflex, glucose-induced insulin secretion, and acetyicholine release from hippocampus. Our present aim was to investigate whether M35 and C7 can affect galanin-induced inhibition of pancreatic enzyme secretion in rats. Pancreatic enzyme secretion was studied in urethane-anesthetized rats supplied with jugular vein catheter and pancreatic cannula. Amylase secretion evoked by submaximal CCK-8 stimulation was inhibited dose-dependently by galanin in anesthetized rats. Surprisingly, neither M35 nor C7 was able to inhibit the responses of the exocrine pancreas to galanin. However, both putative galanin receptor antagonists behaved as agonists in our experimental models. Our data suggest that the effects of galanin on pancreatic enzyme secretion are not mediated by M35- or C7-sensitive galanin receptors. Therefore, these galanin receptors are different from those described in the central nervous system.