Vibrio cholerae O139 persists in Dhaka,Bangladesh since 1993

BackgroundAfter a multi-country Asian outbreak of cholera due to Vibrio cholerae serogroup O139 which started in 1992, it is rarely detected from any country in Asia and has not been detected from patients in Africa.Methodology/Principal findingsWe extracted surveillance data from the Dhaka and Matlab Hospitals of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) to review trends in isolation of Vibrio cholerae O139 in Bangladesh. Data from the Dhaka Hospital is a 2% sample of > 100,000 diarrhoeal patients treated annually. Data from the Matlab Hospital includes all diarrhoeal patients who hail from the villages included in the Matlab Health and Demographic Surveillance System. Vibrio cholerae O139 was first isolated in Dhaka in 1993 and had been isolated every year since then except for a gap between 2005 and 2008. An average of thirteen isolates was detected annually from the Dhaka Hospital during the last ten years, yielding an estimated 650 cases annually at this hospital. During the last ten years, cases due to serogroup O139 represented 0.47% of all cholera cases; the others being due to serogroup O1. No cases with serogroup O139 were identified at Matlab since 2006. Clinical signs and symptoms of cholera due to serogroup O139 were similar to cases due to serogroup O1 though more of the O139 cases were not dehydrated. Most isolates of O139 remained sensitive to tetracycline, ciprofloxacin, and azithromycin, but they became resistant to erythromycin starting in 2009.Conclusions/SignificanceCholera due to Vibrio cholerae serogroup O139 continues to cause typical cholera in Dhaka, Bangladesh.     

Whole-genome sequence of the xylanase-producing Mesoflavibacter zeaxanthinifaciens strain S86

We isolated Mesoflavibacter zeaxanthinifaciens S86 as xylanase-producing bacteria from seawater sampled in Micronesia. Analysis of the M. zeaxanthinifaciens genome revealed that it contains a single circular chromosome of 3,704,661 bp with 3,249 putative open reading frames.     

Concentration- and time-dependent effects of enoxaparin on human adenocarcinomic epithelial cell line A549 proliferation in vitro

Non-small cell lung cancer (NSCLC) is a major health problem. Surgery is the only potential curative treatment, in spite of the high recurrence and mortality rates. Low molecular weight heparins (LMWH) have been suggested to have a positive impact on the outcome of various cancers, mainly attributed to their anticoagulant properties; yet a direct antineoplastic effect has not been excluded. We thought to evaluate the direct effect of the LMWH enoxaparin on the human lung adenocarcinomic epithelial cell line A549 and to determine potential antiproliferative and antimetastatic effects that could guide future trials. A549 cells were cultured with different concentrations of enoxaparin (1-30 U/mL). Cell counting was performed at 24, 48, and 72 h. Detection of c-Myc protein and CD44 protein was performed by electrophoresis and Western blotting. Statistical analysis was performed using paired Student's t tests. Cell counts were decreased with increasing concentrations and time of exposure to enoxaparin. This corresponds to decreased expression of c-Myc and CD44. In conclusion, enoxaparin displayed a direct dose and exposure duration dependent suppressor effect on A549 cell proliferation and the expression of both c-Myc and CD44 in vitro, suggesting reduced proliferative and metastatic potentials of these cells.     

Predominant genera of fecal microbiota in children with atopic dermatitis are not altered by intake of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium animalis subsp. lactis Bi-07

The effect of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 on the composition of the Lactobacillus group, Bifidobacterium and the total bacterial population in feces from young children with atopic dermatitis was investigated. The study included 50 children randomized to intake of one of the probiotic strain or placebo. Microbial composition was characterized by denaturing gradient gel electrophoresis, quantitative PCR and, in a subset of subjects, by pyrosequencing of the 16S rRNA gene. The core population of the Lactobacillus group was identified as Lactobacillus gasseri, Lactobacillus fermentum, Lactobacillus oris, Leuconostoc mesenteroides, while the bifidobacterial community included Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium longum and Bifidobacterium catenulatum. The fecal numbers of L. acidophilus and B. lactis increased significantly after intervention, indicating survival of the ingested bacteria. The levels of Bifidobacterium correlated positively (P=0.03), while the levels of the Lactobacillus group negatively (P=0.01) with improvement of atopic eczema evaluated by the Severity Scoring of Atopic Dermatitis index. This correlation was observed across the whole study cohort and not attributed to the probiotic intake. The main conclusion of the study is that administration of L. acidophilus NCFM and B. lactis Bi-07 does not affect the composition and diversity of the main bacterial populations in feces.     

The effect of RA on the chick Ebf1-3 genes expression in somites and pharyngeal arches

Expression of chick early B cell factor 1-3 (cEbf1-3) genes in regions of high retinoic acid (RA) activity, such as somites and pharyngeal arches (PAs), and regulation of other EBF members by RA raise the possibility that the internal cue RA may regulate cEbf1-3 expression in these tissues. To check this possibility, RA gain and loss of function experiments were conducted. Ectopic expression of RA led to up-regulation of cEbf2, 3 but did not change cEbf1 expression in somites. Expectedly, inhibition of RA by disulfiram resulted in downregulation of cEbf2, 3, but did not change cEbf1 expression in somites. The same RA gain and loss of function experiments did not change cEbf1-3 expression in PAs. However, ectopic expression of RA in the cranial neural tube before migration of neural crest cells downregulated cEbf1, 3 and up-regulated cEbf2 expression in the PAs. The same experiment, but with application of disulfiram, resulted in downregulation of cEbf2, but did not alter the expression of the other two genes. We conclude that the three cEbf genes act differently in response to RA signals in somitic mesoderm. cEbf1 may be not RA dependant in somites; however, the other two cEbf genes positively respond to RA signalling in somites. Additionally, only the migratory cEbf-expressing cells into the PAs are affected by RA signals.     

A comparative genomic analysis of the alkalitolerant soil bacterium Bacillus lehensis G1

Bacillus lehensis G1 is a Gram-positive, moderately alkalitolerant bacterium isolated from soil samples. B. lehensis produces cyclodextrin glucanotransferase (CGTase), an enzyme that has enabled the extensive use of cyclodextrin in foodstuffs, chemicals, and pharmaceuticals. The genome sequence of B. lehensis G1 consists of a single circular 3.99 Mb chromosome containing 4017 protein-coding sequences (CDSs), of which 2818 (70.15%) have assigned biological roles, 936 (23.30%) have conserved domains with unknown functions, and 263 (6.55%) have no match with any protein database. Bacillus clausii KSM-K16 was established as the closest relative to B. lehensis G1 based on gene content similarity and 16S rRNA phylogenetic analysis. A total of 2820 proteins from B. lehensis G1 were found to have orthologues in B. clausii, including sodium–proton antiporters, transport proteins, and proteins involved in ATP synthesis. A comparative analysis of these proteins and those in B. clausii and other alkaliphilic Bacillus species was carried out to investigate their contributions towards the alkalitolerance of the microorganism. The similarities and differences in alkalitolerance-related genes among alkalitolerant/alkaliphilic Bacillus species highlight the complex mechanism of pH homeostasis. The B. lehensis G1 genome was also mined for proteins and enzymes with potential viability for industrial and commercial purposes.     

Molecular cloning,expression and characterisation of Afp4, an antifreeze protein from Glaciozyma antarctica

Antifreeze proteins (AFPs) are proteins with affinity towards ice and contribute to the survival of psychrophiles in subzero environment. Limited studies have been conducted on how AFPs from psychrophilic yeasts interact with ice. In this study, we describe the functional properties of an antifreeze protein from a psychrophilic Antarctic yeast, Glaciozyma antarctica. A cDNA encoding the antifreeze protein, AFP4, from G. antarctica PI12 was amplified from the mRNA extracted from cells grown at 4 °C. Sequence characterisation of Afp4 showed high similarity to fungal AFPs from Leucosporidium sp. AY30, LeIBP (93 %). The 786-bp cDNA encodes a 261-amino-acid protein with a theoretical pI of 4.4. Attempts to produce the recombinant Afp4 in Escherichia coli resulted in the formation of inclusion bodies (IB). The IB were subsequently denatured and refolded by dilution. Gel filtration confirmed that the refolded recombinant Afp4 is monomeric with molecular mass of ~25 kDa. Thermal hysteresis (TH) and recrystallisation inhibition assays confirmed the function of Afp4 as an antifreeze protein. In the presence of Afp4, ice crystals were modified into hexagonal shapes with TH values of 0.08 °C and smaller ice grains were observed compared with solutions without AFP. Structural analyses via homology modelling showed that Afp4 folds into β-helices with three distinct faces: a, b and c. Superimposition analyses predicted the b-face as the ice-binding surface of Afp4, whereby the mechanism of interaction is driven by hydrophobic interactions and the flatness of surface. This study may contribute towards an understanding of AFPs from psychrophilic yeasts.