Genomic diversity of 2010 Haitian cholera outbreak strains.

The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortality of cholera in Haiti since October 2010, are grim reminders that Vibrio cholerae, the etiologic agent of cholera, remains a scourge. We report the isolation of both V. cholerae O1 and non-O1/O139 early in the Haiti cholera epidemic from samples collected from victims in 18 towns across eight Arrondissements of Haiti. The results showed two distinct populations of V. cholerae coexisted in Haiti early in the epidemic. As non-O1/O139 V. cholerae was the sole pathogen isolated from 21% of the clinical specimens, its role in this epidemic, either alone or in concert with V. cholerae O1, cannot be dismissed. A genomic approach was used to examine similarities and differences among the Haitian V. cholerae O1 and V. cholerae non-O1/O139 strains. A total of 47 V. cholerae O1 and 29 V. cholerae non-O1/O139 isolates from patients and the environment were sequenced. Comparative genome analyses of the 76 genomes and eight reference strains of V. cholerae isolated in concurrent epidemics outside Haiti and 27 V. cholerae genomes available in the public database demonstrated substantial diversity of V. cholerae and ongoing flux within its genome.

Clinicopathological correlation of acute appendicitis.

Acute appendicitis is the most common acute surgical condition of the abdomen and appendicectomy is the most frequently performed urgent abdominal operation. Delay in treatment of acute appendicitis causes lot of complications. On the other hand, to reduce complications prompt diagnosis and treatment results lot of negative laparotomy (as high as 25%). The prime aim of this study was to reduce the incidence of negative laparotomy.

Formation of anti-sense RNA to IFN mRNA in poly (rI):(rC) induced HEL cells.

To elucidate the mechanism of super induction of IFN, mRNA and anti-sense RNA were analyzed by using reverse transcription-polymerase chain reaction (RT-PCR) method, and following results were obtained. (1) When human embryonic lung fibroblast cells (HEL cells) were exposed to poly (rI):(rC) for 1 hr, treated with cycloheximide for 3 hr, treated with actinomycin-D for 30 min at the final period of cycloheximide treatment, then washed and replenished with maintenance medium, (HEL-I:C/CH/Act. D), they produced much higher amount of IFN and IFN production continued for longer period when compared to the HEL cells which were not treated with actinomycin-D (HEL-I:C/CH). In agreement with these IFN production kinetics, HuIFN-beta mRNA was stabilized in HEL-I:C/CH/Act. D. In HEL-I:C/CH/Act.D, the mRNA was detected at the end of cloheximide treatment (4 hr after induction) and 6 hr after induction, however, it was not detected at 6 hr after induction in HEL-I:C/CH. (2) Anti-sense RNA was detected in HEL-I:C/CH/Act.D at 4 hr and 6 hr after induction, and also in HEL-I:C/CH at 4 hr after induction, however, it was not detected at 6 hr after induction in HEL-I:C/CH. These results indicated that an anti-sense RNA to HuIFN-beta mRNA was formed in poly (rI):(rC) induced HEL cells, and that aRNA had the same fate as mRNA, suggesting it's role in the regulation of IFN production. Possible role of aRNA in the regulation mechanism of IFN production was discussed.

11beta-Hydroxylation of Cortexolone (Reichstein Compound S) to Hydrocortisone by Curvularia lunata Entrapped in Photo-Cross-Linked Resin Gels.

Spores of Curvularia lunata were immobilized by entrapment with photo-cross-linkable resin prepolymers and incubated to form mycelium in potato dextrose broth containing cortexolone (Reichstein compound S) as an inducer of steroid 11beta-hydroxylase. In a buffer system containing 2.5% dimethyl sulfoxide, this immobilized mycelium hydroxylated cortexolone to hydrocortisone. The activity of this mycelium was comparable to the activity of free mycelium. Dimethyl sulfoxide did not inhibit hydroxylase activity at the concentration used and was effective in dissolving the product. Of the various photo-cross-linkable resin prepolymers examined, use of ENT-4000, whose main chain was polyethylene glycol 4000 (chain length, approximately 40 nm), resulted in maximum hydroxylation activity of the entrapped mycelium. The chain length of prepolymers affected markedly mycelial growth in the gels and, subsequently, the activity of the entrapped mycelium. The immobilized hydroxylation system was more stable than the system in free mycelium and could be reactivated by incubation of the entrapped mycelium in potato dextrose broth containing cortexolone. The system was tested 50 times during 100 days of operation and was found to carry out the desired transformation with overall yields of 60%.

Enterotoxicity ofVibrio furnissii isolated from eels.

Fourteen strains ofVibrio furnissii, isolated from different ulcerated areas of eel, were tested to check their enterotoxicity in an animal model. Most strains caused fluid accumulation in ileal loop tests after serial passages and culture filtrates of most of the strains caused induration and increase in vascular permeability in rabbit skin. Production of extracellular haemolysin was also detected in all the culture filtrates. All of these observations clearly establish the enterotoxicity of these organisms.

Isolation and characterization of a cellulase-free pectinolytic and hemicellulolytic thermophilic fungus.

A thermophilic fungus belonging to the Deuteromyces, having pectinase and xylanase activities, was grown at its optimum temperature of 55°C. It grew over a wide pH range of 4 to 10, being optimal at 6. The fungus grew well on modified Mandels' medium in which cellulose was substituted either with hemicellulose or pectin. With citrus pectin as carbon source, 121 units/ml of pectinase activity were obtained and with larch wood xylan as carbon source, 83 units/ml of xylanase activity were obtained.

Role of gamma delta TCR+ lymphocytes in the augmented resistance of trehalose 6,6'-dimycolate-treated mice to influenza virus infection.

Trehalose 6,6'-dimycolate (TDM), an immunomodulator, potentiates non-specific resistance in mice to influenza virus infection. When mice were injected intravenously with TDM, the striking proliferation of a minority of T-lymphocytes bearing gamma/delta T-cell receptors (gamma delta T-cells) that accumulated in granulomatous lungs was thought to be associated with the maintenance of acquired resistance to lethal influenza virus infection. To clarify the cellular basis of the defence against influenza virus, mice were depleted of gamma delta T-cells, alpha/beta (alpha beta) T-cells, or natural killer (NK) cells by in vivo administration of corresponding antibodies prior to influenza virus infection. The depletion of gamma delta T-cells significantly abrogated the augmented resistance of TDM-treated mice to infection, as did depletion of either alpha beta T-cells or NK cells. To gain insight into the functional ability of gamma delta T-cells, we evaluated the cytotoxic activity of this T-cell subset against a panel of target cell lines that were stably transfected with the influenza virus haemagglutinin (HA) gene from A/PR/8/34(H1N1) and A/Aichi/2/68(H3N2) strains. The gamma delta T-cells from TDM-treated mice showed profound cytotoxicity against the target cells expressing HA of either the H1 or H3 subtype, in a non-major histocompatibility complex-restricted manner. Taken together, these results indicate that gamma delta T-cells play a non-specific role, in conjunction with alpha beta T-cells and NK cells, in protecting mice against influenza virus infection, and that the recognition and destruction of HA-expressing target cells by the activated gamma delta T-cells is one of the steps involved in this anti-influenza virus immunosurveillance.

Physicochemical properties of a novel alpha-L-arabinofuranosidase from Rhizomucor pusillus HHT-1.

The zygomycete fungus Rhizomucor pusillus HHT-1, cultured on L(+)arabinose as a sole carbon source, produced extracellular alpha-L-arabinofuranosidase. The enzyme was purified by (NH4)2SO4 fractionation, gel filtration, and ion exchange chromatography. The molecular mass of this monomeric enzyme was 88 kDa. The native enzyme had a pI of 4.2 and displayed a pH optimum and stability of 4.0 and 7.0-10.0, respectively. The temperature optimum was 65 degrees C, and it was stable up to 70 degrees C. The Km and Vmax for p-nitrophenyl alpha-L-arabinofuranoside were 0.59 mM and 387 micromol x min(-1) x mg(-1) protein, respectively. Activity was not stimulated by metal cofactors. The N-terminal amino acid sequence did not show any similarity to other arabinofuranosidases. Higher hydrolytic activity was recorded with pnitrophenyl alpha-L-arabinofuranoside, arabinotriose, and sugar beet arabinan; lower hydrolytic activity was recorded with oat-spelt xylan and arabinogalactan, indicating specificity for the low molecular mass L(+)-arabinose containing oligosaccharides with furanoside configuration.

Antibiotic resistance pattern of heat-labile enterotoxin (LT) producing Escherichia coli isolated from children with diarrhoea in Bangladesh: clonal relationships among isolates with different resistant phenotypes.

Fifty-six heat-labile, enterotoxin-producing (LT+) Escherichia coli isolated from 33 children less than 5 years of age with diarrhoea were analysed for resistance to antibiotics, plasmid contents, and clonal relationships among isolates by ribosomal RNA (rRNA) fingerprinting (ribotyping). Fifty-five (98.2%) of the LT+ isolates were resistant either to tetracycline alone (48.2%) or to tetracycline and one or more other antibiotic, i.e. ampicillin, streptomycin, chloramphenicol, trimethoprim-sulfamethoxazole, or nalidixic acid. Most of the isolates harboured one or more plasmid but antibiotic resistance patterns did not always correlate with particular plasmid patterns. Ribotyping of the isolates using the restriction endonuclease EcoRI revealed a total of 7 different ribotypes, and ribotypes were shared by E. coli isolates with different antibiotic resistant phenotypes. The results indicate that in Bangladesh at least 7 different clones of LT+ E. coli acquired resistance to one or more different antibiotics in various combinations. However, a similar drug resistance pattern was not mediated by the same set of plasmids in all strains. The mechanism for the emergence and spread of antibiotic resistance among E. coli should be investigated further in Bangladesh, where LT+ E. coli is an important agent of early childhood diarrhoea.

Insufficient resistance of trehalose-6,6-dimycolate-treated T-cell receptor delta gene mutant (TCR delta-/-) mice against influenza virus infection.

Normal mice inoculated intravenously with 50 microg trehalose-6,6'-dimycolate, a glycolipid component of the cell wall of Mycobacterium, in an oil-in-water emulsion (TDM emulsion) acquired a high resistance to intranasal lethal infection of an influenza virus. In contrast, TDM emulsion-treated T-cell receptor delta gene mutant (TCR delta-/-) mice acquired insufficient resistance against the lethal influenza virus infection. The patterns of insufficient resistance were identical to the results obtained previously with mice which were depleted of T-lymphocytes bearing gammadelta T-cell receptors (gammadelta T-cells) by in vivo administration of anti-gammadelta T-cell receptor monoclonal antibody (Hoq et al, J. Gen. Virol. 78: 1597-1603, 1997). These results strongly suggest that the gammadelta T-cells play an important non-specific role in resistance against influenza virus infection.