Holothuria triterpene glycosides: a comprehensive guide for their structure elucidation and critical appraisal of reported compounds

Phytochemistry Reviews - Sea cucumbers or holothurians are marine invertebrates, belonging to the phylum Echinodermata (kingdom Animalia). In Asia, they are commonly used as food, while they are...     

The role of human innate immune factors in nasal colonization by Staphylococcus aureus

Staphylococcus aureus colonization of the human nares predisposes to sometimes severe auto-infection. To investigate whether genetic polymorphism affects the S. aureus carriage status, sequence variation in alpha-defensin and beta-defensin, and mannose-binding lectin (MBL) genes were determined for a group of volunteers (n=109) with known S. aureus nasal carriage status. DEFA1/3 expression was measured in a subset of the volunteers (n=32). None of the single nucleotide polymorphisms studied could clearly distinguish the (non) carriage groups. S. aureus carriers differed from non-carriers in baseline level of HNP1-3 peptide production (median: 218 versus 89mug/ml, P=0.016). No association between HNP1-3 levels and the individual sequence polymorphisms was documented. The combined copy numbers of DEFA1/A3 genes ranged from 5 to 23 per diploid genome. A linear correlation between combined copy numbers and HNP1-3 peptide concentrations in nasal secretions of non-carriers was noted (r(2)=0.8991). DEFA3 gene was absent in 25% of the individuals. MBL haplotype A was overrepresented in persistent S. aureus carriers (87% vs. 67%; P=0.038). In conclusion, defensin gene polymorphism, both in sequence and in gene copy numbers, does not seem to be involved in S. aureus carriage predisposition. However, MBL haplotypes do so significantly. Baseline HNP1-3 production is more the consequence of S. aureus colonization than a reason for the (non) carrier status.     

Identification and characterization of starter lactic acid bacteria and probiotics from Columbian dairy products

AIMS: Considering the significant rise in the probiotic market in Columbia, and given the lack of reports concerning the microbial population and strain performance in products from different producers, this study aims at determining the number of viable starter bacteria and probiotics in bio-yoghurts available at the Columbian market, identifying the species and analysing the performance of the isolated strains in bile acid resistance, antagonistic activity against pathogens, and adherence capacity to human intestinal epithelial cells. METHODS AND RESULTS: Seven bio-yoghurts were analysed for the bacterial species present. Species identification was carried out using 16S rRNA gene targeted PCR. The cultured bacteria were tested for bile acid resistance, adherence to a human intestinal epithelial cell line, and antagonism against the pathogen Salmonella enterica serovar Typhimurium. A total of 17 different strains were identified. Based on plate counting, all bio-yoghurts have at least total viable cells of approximately 10(7) CFU ml(-1). Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were the most frequently isolated bacteria. Viable Bifidobacterium was only recovered from one product. However, after PCR analysis, DNA of this genus was confirmed in five out of seven products. Major differences were found for S. typhimurium antagonism. The adherence capacity to Caco-2 cells was observed in 10 of the isolated strains. In general, low survival to simulated gastric juice was observed. CONCLUSIONS: Some of the isolated strains have probiotic potential, although not all of them were present in the advised amount to exert beneficial health effects. However, the full correct scientific name of the isolated bacteria and their viable counts were not included on the product label. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report describing the identification and functionality of starter bacteria and probiotics present in dairy products on the Columbian market.     

Stimulation by caveolin-1 of the hypotonicity-induced release of taurine and ATP at basolateral, but not apical, membrane of Caco-2 cells

Regulatory volume decrease (RVD) is a protective mechanism that allows mammalian cells to restore their volume when exposed to a hypotonic environment. A key component of RVD is the release of K⁺, Cl^–, and organic osmolytes, such as taurine, which then drives osmotic water efflux. Previous experiments have indicated that caveolin-1, a coat protein of caveolae microdomains in the plasma membrane, promotes the swelling-induced Cl^– current (I_Cl,swell) through volume-regulated anion channels. However, it is not known whether the stimulation by caveolin-1 is restricted to the release of Cl^– or whether it also affects the swelling-induced release of other components, such as organic osmolytes. To address this problem, we have studied I_Cl,swell and the hypotonicity-induced release of taurine and ATP in wild-type Caco-2 cells that are caveolin-1 deficient and in stably transfected Caco-2 cells that express caveolin-1. Electrophysiological characterization of wild-type and stably transfected Caco-2 showed that caveolin-1 promoted I_Cl,swell, but not cystic fibrosis transmembrane conductance regulator currents. Furthermore, caveolin-1 expression stimulated the hypotonicity-induced release of taurine and ATP in stably transfected Caco-2 cells grown as a monolayer. Interestingly, the effect of caveolin-1 was polarized because only the release at the basolateral membrane, but not at the apical membrane, was increased. It is therefore concluded that caveolin-1 facilitates the hypotonicity-induced release of Cl^–, taurine, and ATP, and that in polarized epithelial cells, the effect of caveolin-1 is compartmentalized to the basolateral membrane. caveolae; osmolyte; epithelial cell; chloride channel     

Infectious salmon anaemia virus (ISAV) isolated from the ISA disease outbreaks in Chile diverged from ISAV isolates from Norway around 1996 and was disseminated around 2005, based on surface glycoprotein gene sequences

Background

All viruses in the family Bunyaviridae possess a tripartite genome, consisting of a small, a medium, and a large RNA segment. Bunyaviruses therefore possess considerable evolutionary potential, attributable to both intramolecular changes and to genome segment reassortment. Hantaviruses (family Bunyaviridae, genus Hantavirus) are known to cause human hemorrhagic fever with renal syndrome or hantavirus pulmonary syndrome. The primary reservoir host of Sin Nombre virus is the deer mouse (Peromyscus maniculatus), which is widely distributed in North America. We investigated the prevalence of intramolecular changes and of genomic reassortment among Sin Nombre viruses detected in deer mice in three western states.

Methods

Portions of the Sin Nombre virus small (S) and medium (M) RNA segments were amplified by RT-PCR from kidney, lung, liver and spleen of seropositive peromyscine rodents, principally deer mice, collected in Colorado, New Mexico and Montana from 1995 to 2007. Both a 142 nucleotide (nt) amplicon of the M segment, encoding a portion of the G2 transmembrane glycoprotein, and a 751 nt amplicon of the S segment, encoding part of the nucleocapsid protein, were cloned and sequenced from 19 deer mice and from one brush mouse (P. boylii), S RNA but not M RNA from one deer mouse, and M RNA but not S RNA from another deer mouse.

Results

Two of 20 viruses were found to be reassortants. Within virus sequences from different rodents, the average rate of synonymous substitutions among all pair-wise comparisons (π_s) was 0.378 in the M segment and 0.312 in the S segment sequences. The replacement substitution rate (π_a) was 7.0 × 10^-4 in the M segment and 17.3 × 10^-4 in the S segment sequences. The low π_a relative to π_s suggests strong purifying selection and this was confirmed by a Fu and Li analysis. The absolute rate of molecular evolution of the M segment was 6.76 × 10^-3 substitutions/site/year. The absolute age of the M segment tree was estimated to be 37 years. In the S segment the rate of molecular evolution was 1.93 × 10^-3 substitutions/site/year and the absolute age of the tree was 106 years. Assuming that mice were infected with a single Sin Nombre virus genotype, phylogenetic analyses revealed that 10% (2/20) of viruses were reassortants, similar to the 14% (6/43) found in a previous report.

Conclusion

Age estimates from both segments suggest that Sin Nombre virus has evolved within the past 37–106 years. The rates of evolutionary changes reported here suggest that Sin Nombre virus M and S segment reassortment occurs frequently in nature.     

Copper tolerance in the cuprophyte Haumaniastrum katangense (S. Moore) P.A. Duvign. & Plancke

Cu tolerance and accumulation have been studied in Haumaniastrum katangense, a cuprophyte from Katanga (DR Congo), previously described as a copper hyperaccumulator. Nicotiana plumbaginifolia, a well-known non-tolerant and non-accumulator species, was used as a control. The germination rate of H. katangense was enhanced by copper and fungicide addition, suggesting that fungal pathogens, which restrain germination in normal conditions, are limiting. In hydroponic culture in the Hoagland medium, H. katangense did not grow well, in contrast to N. plumbaginifolia. Better growth was achieved by adding fungicide or higher copper concentrations. The maximal non-effective concentration (NEC) was 12 µM CuSO₄ for H. katangense grown in hydroponics, i.e. 24 times greater than Cu concentration in the Hoagland medium. By comparison, copper concentrations greater than 0.5 µM had a negative effect on the growth of N. plumbaginifolia. EC₅₀ (50% effective concentration) in hydroponics was 40 µM CuSO₄ for H. katangense and 6 µM CuSO₄ for N. plumbaginifolia. EC₁₀₀ (100% effective concentration) was 100 µM CuSO₄ for H. katangense and 15 µM CuSO₄ for N. plumbaginifolia. In soil, growth was also stimulated by Cu addition up to 300 mg kg^-1 CuSO₄. Surplus copper was also required for cultivating H. katangense in sterile conditions, suggesting that Cu excess may be necessary for needs other than pathogen defence. Cu accumulation in the shoot has been measured for N. plumbaginifolia and H. katangense at their respective NEC. Cu allocation in the two species showed a similar response to increasing Cu concentrations, i.e. root/shoot concentration ratio well above 1. In conclusion, H. katangense is highly tolerant to copper and has elevated copper requirement even in the absence of biotic interactions. Its accumulation pattern is typical of an excluder species.