Use of pretreated lignocellulose for the production of cellulases

Summary Tests made to utilize lignocellulosics as a substrate for the production of cellulases showed that the enzyme production from steam and explosion decompressed aspen wood (SED) by Tricoderma reesei RUT-C30 was low, and the enzyme system produced was deficient in exoglucanase and -glucosidase activities. Mixing this substrate with 10–20% pure cellulose lessened this deficiency and improved enzyme production. The enzyme system produced from the mixed substrate was rich in xylanase and had saccharifying ability equal to that produced in medium containing pure cellulose.     

A small camel-milk protein rich in cysteine/half-cystine

A small protein (M_r about 14 000) rich in cysteine/half-cystine has been isolated from camel milk by exclusion chromatography and reverse-phase high-performance liquid chromatography. The N-terminal amino acid sequence shows a region with several positional identities with and -caseins, which however lack cysteine residues; postions 16–20 are identical and involve the serine residues that have been found to be phosphorylated in -caseins.     

Transport of carnosine by mouse intestinal brush-border membrane vesicles

The characteristics of carnosine (beta-alanyl-L-histidine) transport have been studied using purified brush-border membrane vesicles from mouse small intestine. Uptake curves did not exhibit any overshoot phenomena, and were similar under Na+, K+ or choline+ gradient conditions (extravesicular greater than intravesicular). However, uptake of histidine showed an overshoot phenomenon in the presence of a Na+-gradient. There was no detectable hydrolysis of carnosine during 15 min of incubation with membrane vesicles under conditions used for transport experiments. Analysis of intravesicular contents further showed the complete absence of the constituent free amino acids of carnosine, and indicates that intact carnosine is transported. Studies on the effect of concentration on peptide uptake revealed that transport occurred by a saturable process conforming to Michaelis-Menten kinetics with a Km of 9.6 +/- 1.4 mM and a Vmax of 2.9 +/- 0.2 nmol/mg protein per 0.4 min. Uptake of carnosine was inhibited by both di- and tripeptides with a maximum inhibition of 68% by glycyl-L-leucyltyrosine. These results clearly demonstrate that carnosine is transported intact by a carrier-mediated, Na+-independent process.     

Cellulase and Sugar Formation by Bacteroides cellulosolvens, a Newly Isolated Cellulolytic Anaerobe

A newly isolated mesophilic anaerobe, Bacteroides cellulosolvens, has the ability to produce cellulase and to degrade cellulose to cellobiose and glucose. It does not utilize glucose, and it lacks β-glucosidase activity. This anaerobe appears to degrade cellulose to cellobiose by cellulase action, and the presence of cells appears necessary for the formation of glucose.     

Butylphenyl dGTP: a selective and potent inhibitor of mammalian DNA polymerase alpha.

BuPdGTP , the 2'-deoxyribonucleoside 5'-triphosphate of the DNA polymerase alpha (pol alpha)-specific inhibitor, N2-(p-n- butylphenyl )guanine, was examined with respect to its mechanism and its capacity to inhibit the mammalian DNA polymerases, pol alpha, pol beta, and pol gamma. BuP dGTP was specifically inhibitory for pol alpha, with no discernible activity on pol beta and pol gamma. The potency of BuP dGTP is unprecedented, with an apparent Ki less than 10 nanomolar. The unusual potency of the BuP dGTP is derived primarily from the 5' alpha and beta phosphoryl moieties, whose binding to enzyme complements that of the base-linked butylphenyl substituent. BuP dGTP is competitive with dGTP and apparently not subject to polymerization. Experiments employing BuP dGTP in the presence of a non-complementary template suggest that the core polymerase or an associated coprotein contains dNTP binding sites which recognize specific nucleic acid bases. The partial sensitivity of selected, non-mammalian DNA polymerases suggests that modification of the N2 substituent of dGTP will be a useful route to the design of novel, polymerase-specific affinity-probes.     

Allergic bronchopulmonary aspergillosis (ABPA): Studies on the general and specific humoral response

Serum specimens from 138 patients suffering from chronic respiratory disorders including 63 with allergic bronchopulmonary aspergillosis (ABPA), 20 with suspected ABPA, 25 with pulmonary tuberculosis, 14 with bronchial asthma, 10 with chronic bronchitis and 6 with miscellaneous pulmonary conditions were studied for circulating antibodies to Aspergillus. The ammonium sulfate test was employed with an iodine-125 labeled mycelial component derived from Aspergillus fumigatus. When compared to normal controls from the same area, this test indicated that sera from 82 per cent of patients with ABPA had elevated binding titers to the radiolabeled antigenic component. Immunodiffusion using a culture filtrate antigen from A. fumigatus, revealed precipitating antibody to this fungus in 89 per cent of sera from ABPA patients. The majority of patients with ABPA demonstrated marked elevations of total serum IgE, moderate elevations of serum IgA and IgD and slightly increased levels of IgG and IgM.This study was supported in part by Research Grant AI 10940 from the National Institutes of Health and by NHLI Contract N01-HL-3-2942(B), and forms a part of the Ph.D. thesis submitted by Z.U.K. to the University of Delhi.     

Localization of a gene for human α-galactosidase B (=N-Acetyl-α-D-Galactosaminidase) on chromosome 22

Summary The localization of the structural gene for human -galactosidase B (=N-acetyl--galactosaminidase) was investigated by means of man-Chinese hamster and man-mouse somatic cell hybrids. The hybrid clones were analyzed for chromosomes and for a large number of known enzyme markers. The lysates of the hybrid cells were treated with Sepharose-coupled antihuman -galactosidase B and the activity of the adsorbed enzyme was measured on the Sepharose beads as N-acetyl--galactosominidase. The results show that the structural gene for human -galactosidase B is situated on chromosome 22, and that there is no structural relationship between human -galactosidase A and human -galactosidase B.     

Mycoplasma Phosphoenolpyruvate-Dependent Sugar Phosphotransferase System: Purification and Characterization of Enzyme I

The Mycoplasma phosphoenolpyruvate-dependent sugar phosphotransferase system consists of three components: a membrane-bound enzyme II, a soluble phosphocarrier protein (HPr), and a soluble enzyme I. The soluble enzyme I was purified by ammonium sulfate fractionation; Bio-Gel P-10 gel filtration; acid precipitation; diethylaminoethyl-Bio-Gel A; and Bio-Gel HTP column chromatography. The enzyme I was shown to be homogeneous by electrophoresis in a pH 8.9 non-sodium dodecyl sulfate gel and by isoelectric focusing. Whereas the protein moved as a single component in both the non-sodium dodecyl sulfate gel and isoelectric focusing, on sodium dodecyl sulfate gels, it moved as three subcomponents. The molecular weights of the three subunits, alpha, beta, and gamma, were 44,500, 62,000 and 64,500, respectively. The holoprotein moved as a single component, in the region of 220,000 daltons, in a Bio-Gel A 0.5-agarose column. The molar ratio of subunits was estimated to be 2alpha:1beta:1gamma. The elution characteristics on a diethylaminoethyl column at pH 7.4 and 6.8, acid precipitation data, and amino acid composition indicated that the protein is acidic. Isoelectric focusing occurred at pH 4.8. N-terminal amino acids determined by the dansyl chloride method indicated that glycine, alanine, and tyrosine are N-terminal amino acids of the three subunits. Although the protein was stable for at least 14 months at -20 degrees C, it was irreversibly inactivated by the thiol reagent N-ethyl-maleimide.     

Photodynamic treatment of herpes simplex virus during its replicative cycle.

Photodynamic treatment of herpes simplex virus type 1-infected hamster embryo fibroblasts (LSH strain) with a low concentration of proflavine (0.08 mug/10(5) cells per ml), a 3-9-diamine acridine dye, inhibited production not only of infectious progeny but also of virion particles. However, there was no appreciable inhibition of viral or cellular DNA synthesis, even when the infected cells were repeatedly exposed to this low concentration of dye and light during the replication cycle of the virus. It thus appears that photodynamic treatment of infected cells interferes with the processes involved in virus maturation.     

Feline leukemia virus: biochemical and immunological characterization of gag gene-coded structural proteins.

The major non-glycosylated structural proteins of feline leukemia virus have been isolated, and competition immunoassays have been developed for each. These proteins include the 27,000- to 30,000-molecular-weight major internal antigen designated p30, a 15,000-molecular-weight protein (p15), an acidic protein of 12,000 molecular weight (p12), and a highly basic 10,000-molecular-weight protein (p10). Immunologically and biochemically corresponding proteins of feline and murine leukemia viruses have been identified. and, on the basis of analogy to the known sequence of a prototype type C virus of mouse origin, the map order of the gag region of the feline type C viral genome has been tentatively deduced as NH2-p15-p12-p10-COOH. The demonstration of two feline leukemia virus gag gene-coded proteins, p15 and p12, expressed in the form of an uncleaved precursor in a mink cell line nonproductively transformed by feline sarcoma virus provides indirect support for the proposed sequence.