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The zygomycete fungus Rhizomucor pusillus HHT-1, cultured on L(+)arabinose as a sole carbon source, produced extracellular α-L-arabinofuranosidase. The enzyme was purified by (NH[sub 4] )[sub 2] SO[sub 4] 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°C, and it was stable up to 70°C. The K[sub m] and V[sub max] for p-nitrophenyl α-L-arabinofuranoside were 0.59 mM and 387 µmol·min[sup –1] ·mg[sup –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 p-nitrophenyl α-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.Key words: α-L-arabinofuranosidase, enzyme purification, amino acid sequence, Rhizomucor pusillus.Le champignon zygomycète Rhizomucor pusillus HHT-1, cultivé sur du L(+)-arabinose comme seule source de carbone, a produit de la α-L-arabinofuranosidase extracellulaire. L'enzyme a été purifiée par fractionnement au (NH[sub 4] )[sub 2] SO[sub 4] , filtration sur gel et chromatographie à échange d'ions. Le poids moléculaire de cette enzyme monomérique était de 88 kDa. L'enzyme avait un pI de 4,2, démontrait un pH optimal et une stabilité à 4,0 et 7,0–10,0, respectivement. La température optimale était de 65ºC et l'enzyme était stable jusqu'à 70°C. Le K[sub m] et le V[sub max] pour le p-nitrophényle α-L-arabinofuranoside étaient de 0,59 mM et 387 µmol·min[sup –1] ·mg[sup –1] de protéine, respectivement. L'activité n'a pas été stimulée par des cofacteurs métalliques. La séquence amino-terminale n'a démontré aucune similarité avec d'autres arabinofuranosidases. Une activité hydrolytique supérieure fut mesurée avec du p-nitrophényle α-L-arabinofuranoside, de l'arabinotriose et de l'arabinane de betterave à sucre, et une activité hydrolytique inférieure fut mesurée avec du xylane et de l'arabinogalactane d'épeautre d'avoine, ce qui indique une spécificité pour des oligosaccharides contenant de l'arabinose de petit poids moléculaire ayant un configuration de type furanose.Mots clés : α-L-arabinofuranosidase, purification d'enzymes, séquences d'acides aminés, Rhizomucor pusillus.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Integrated Pest Management (IPM) and bio-intensive pest management (BIPM) (where Bt biopesticide is an indispensible component of it) are the suggested alternatives of chemical pesticides. So, a holistic approach to the isolation and detection of potential Bt strains, production at industrial scale and administration in the field is necessary to include Bt biopesticide in the IPM and BIPM of Bangladesh. In this connection, the bioinsecticide prepared from potential indigenous Bt strain JSc1 was applied in cabbage, cauliflower and organic tea farming and was found to be efficient in controlling the target lepidopteran pests such as Helicoverpa armigera, Spodoptera litura, Plutella xylostella, Hyposidra spp. etc. Results indicated that more than 85% of the treated crops were protected from the infestation and destruction by the pests. Obtained data analyzed using ANOVA test suggested the inclusion of Bt biopesticide in the IPM of Bangladesh as no such differences were observed with the chemical pesticides currently in use. [ABSTRACT FROM AUTHOR]

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.

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.

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.

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.

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.

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%.