Volume 3, Issue 4
December 1981, pages 323-468
pp 323-332 December 1981
An aldolase was partially purified from fermenter grownMycobacterium tuberculosis H37Rv cells. The aldolase has a molecular weight of 150,000, possesses a tetrameric structure and cleaves both fructose diphosphate and fructose-1-phosphate, the former being cleaved 17 times faster. The enzyme was inactivated by treatment with NaBH4 in the presence of fructose diphosphate or dihydroxyacetone, phosphate suggesting Schiff base formation during its catalytic function. Thiol reagents, EDTA and metal ions had no apparent effect on the aldolase activity. These results show that aldolase is of Class I type. However, this enzyme, unlike the mammalian Class I aldolase, was unaffected by carboxypeptidase A. N-ethylmaleiniide and dithionitrobenzoic acid.
pp 333-342 December 1981
Six glycopeptide fractions namely GP-C1, GP-C2. GP-C3a.GP-C3b.GP-D, and GP-D2 were isolated after exhaustive digestion of glucoamylase II (Glucozyme) fromAspergillus niger with pronase. They were purified using gel-filtration. high-voltage paper electrophoresis and ion-exchange chromatography on Dowex-50 and Dowex-1. They appeared homogeneous on electrophoresis under different conditions of pHs. The molecular weights ranged from 1600 and 4000 for these glycopeptides. Ally of them contained serine at the N-terminal end. Serine and threonine were the major amino acids with glycine, alanine, proline and tryosine present as minor constituents. Carbohydrate analysis revealed the presence of different sugars. Based on this, the glycopeptides were grouped into three types: (1) GP-C1 and GP-C2 containing mannose, glucose and galactose; (2) GP-C3a, and GP-C3b,containing mannose glucose and glucosamine; and (3) GP-D1 and GP-D2, containing mannose. glucose, galactose and xylose. Most sugar constituents in each glycopeptide occured in non-integral ratios implying a microheterogeneity of the carbohydrate moiety inAspergillus niger glucoamylase.
pp 343-359 December 1981
Electrophoretically homogeneous type 1 (GP-C1 and GP-C2), type 2 (GP-C3a and GP-C3b,) and type 3 (GP-D1, and GP-D2) glycopeptides fromAspergillus niger glucoamylase II (Manjunath and Raghavendra Rao, preceding paper) were separately treated with alkaline borohydride. The (\-eliminated oligosaccharides were subjected to single and sequential digestion with specific glycosidases and the products analysed by gas liquid chromatography. The studies revealed that carbohydrate moieties were present as mannose, Man-Man-, and trisaccharide structures, namely, (a) GIc-Man-Man-, (b) Gal-Man-Man, (c) Man-Man-Man-, (d) GlcNAc-Man-Man-, and (e) Xyl-Man-Man. None of the glycopeptides contained all the trisaccharide structures (a) to (e). Type 1 glycopeptide contained structures (a), (b) and (c); type 2, (a) and (d) and type 3, (a), (b) and (e). The number of carbohydrate units (mono-, di-and trisaccharides) present in the major glycopeptides was determined and tentative structures for the glycopeptides proposed. Carbohydrate units appeared to occur in clusters of 4 to 7 in each glycopeptide, a structure unique to the carbohydrate moiety inAspergillus niger glucoamylase. Based on carbohydrate analysis and yields of glycopeptide, the number of units of each type of glycopeptide present in glucoamylase II was tentatively calculated to give two of type Man:Glc:Gal = 12–15:l:l, one of type Man:Glc:GlcN = 10-l1:1:2 and one of type Man :GIc :Gal:Xyl = 4–8:0.1:0.5-0.8:0.3-1 glycopeptides.
pp 361-370 December 1981
Free proline content in Ragi (Eleusine coracana) leaves increased markedly (6 to 85 fold) as the degree of water stress, created by polyethylene gylcol treatment, was prolonged There was also a marginal increase in soluble proteins in the stressed leaves as compared to that in the controls. Water stress stimulated the activities of ornithine aminotransferase and pyrroline-5-carboxylate reductase, the enzymes of proline biosynthesis and markedly inhibited the enzymes involved in proline degradation viz., proline oxidase and pyrroline-5-carboxylate dehydrogenase. These results suggest that increase in free proline content of Ragi leaves could be due to enhanced activities of the enzymes synthesizing proline but more importantly due to severe inhibition of the enzymes degrading proline. These observations establish for the first time, the pathway of proline metabolism in plants by way of detection of the activities of all the enzymes involved and also highlight the role of these enzymes in proline accumulation during water stress.
pp 371-377 December 1981
Of the 22 tubers and 9 pulses screened for inhibitors of enterokinase activity, the following 12 tubers,Curcuma amada, Kyllinga monocephala, Solanum tuberosum, Canna indica, Helianthus tuberosus, Coleus parviformis, Mirabilis jalapa, Colocasia antiquorum (red variety),Alium cepa, Amorphophalus companulatus, Maranta arundinacea, Daucus carota, and 9 pulses namely,Vigna sinensis, Arachis hypogea, Pisum sativum, Phaseolus vulgaris (white bean),Phaseolus vulgaris (kidney bean),Phaseolus mungo, Cicer arietinum, Dolichos lablab and Cajonus cajan contained inhibitory activity. Three tubers,Amorphophalus companulatus, Maranta arundinacea andDaucus carota and all the nine pulses exhibited endogenous esterase activity towards benzoyl arginine ethyl ester. Among the 8 pulses and 3 tubers processed by affinity chromatography on trypsin-sepharose, to separate trypsin inhibitor from enterokinase inhibitor,Phaseolus vulgaris (kidney bean),Phaseolus vulgaris (white bean) andDolichos lablab contained distinct enterokinase inhibitors. These fractions were devoid of trypsin inhibitor activity. The trypsin inhibitor fromColeus parviformis tubers alone did not bind to trypsinsepharose and was recovered in the unbound fraction along with the enterokinase inhibitor.
pp 379-388 December 1981
The uptake of benzanthrone by rat skin showed saturation kinetics and was dependent upon the weight of skin and time, temperature and pH of the incubation medium. Heating of segments above 50‡C caused significant lowering of the uptake. The uptake was irreversibly inhibited by HgCl2 and not by sodium arsenate, KCN, NaF,p-chloromercuriben zoate, N-ethyl-maleimide, cycloheximide, iodoacetic acid and 2,4-dinitrophenol suggesting that the uptake was not energy-dependent. Lipid micelles of the skin accounted for a part of the binding. Most of the benzanthrone taken up by the skin was effluxed through serum proteins.
pp 389-393 December 1981
Adult male rats were subjected to whole body irradiation of 400 and 1000 rads and sodium homeostasis in blood was studied on the 1st, 4th and 7th days after exposure. A significant decrease in red cell adenosine triphosphatase, progressive loss of erythrocytic potassium and alteration in influx and efflux of sodium-22 in red cellsin vitro were observed in these rats.
pp 395-400 December 1981
When administered to rats, echitamine was absorbed rapidly from the tissues and was detected in circulation within 30 min. The drug level reached a maximum value by 2 h and then decreased steadily. The drug had completely disappeared from the blood in 6 h. The presence of echitamine was observed within 2 h in urine and the maximum amount of drug was excreted between 2 and 4 h. About 90% of the drug was excreted in urine in 24 h and the drug could not be detected in urine after 48 h. Along with echitamine, its metabolites were also detected in the urine. Plumbagin was not detected in blood upto 24 h when administered into rats. The drug was detected in urine within 4 h after administration; a major portion of the drug was excreted in urine by 24 h and traces of the drug were observed in the urine even after 48 h.
pp 401-406 December 1981
The activity of alkaline phosphate and2+-Mg2+ adenosine triphosphatase, two of the enzymes involved in limpid and calcium uptake across the intestinal membrane, were increased in experimental atherosclerosis. Administration ofAnnapavala sindhooram, an antiatherosclerotic drug, lowers these enzyme levels to near normal values. Prostaglandin E2 stimulated the enzyme activitiesin vitro, while prostaglandin endoperoxide inhibited the activity. Thromboxane and other prostaglandins had no effect on the enzyme activities. Addition of the antiatherosclerotic drug to thein vitro assay system reversed the effect of both prostaglandin E2 and prostaglandin endoperoxide.
pp 407-416 December 1981
The effect of sodium dodecyl sulphate, urea, guanidinium hydrochloride and heat on the oligomeric structure of the 11 S protein of sunflower has been determined. Sodium dodecyl sulphate directly dissociates the protein to 2 S subunits, whereas urea and guanidinium hydrochloride dissociate it through an intermediate 7 S protein. Heating the protein at 90‡C for 20 min caused dissociation of the 11 S protein, without any precipitation.
pp 417-430 December 1981
Approximately 39 to 49% of the genome of finger millet consists of repetitive DNA sequences which intersperse with 18% of single copy DNA sequences of 1900 nucleotide pairs. Agarose gel filtration and electrophoresis experiments have yielded the sizes of interspersed repeated sequences as 4000–4200 nucleotide pairs and 150–200 nucleotide pairs. Approximately 20% of the repeated DNA sequences (4000–4200 nucleotide pairs) are involved in long range interspersion pattern, while 60% of the repeated DNA sequences (150–200 nucleotide pairs) are involved in short period interspersion pattern.
Based on the data available in literature and the results described here on DNA sequence organization in plants, it is proposed that plants with haploid DNA content of more than 2.5 pg exhibit mostly the short period interspersion pattern, while those with haploid DNA content of less than 2.5 pg show diverse patterns of genome organization.
pp 431-438 December 1981
InHaemophilus influenzae genetic transformation for a plasmid marker is significantly increased when recombinant plasmid RSF 0885 DNA carrying chromosomal DNA segments is used instead of the plasmid DNA alone. Chromosomal DNA by itself, added even a few minutes after the addition of plasmid DNA to competent cells, stopped further uptake of the plasmid DNA. These observations are consistent with the idea that plasmid RSF 0885 contains a ‘degenerate’ version of the required eleven base-pair ‘uptake sequence’ inHaemophilus. The transformation activity of the recombinant plasmid DNA is recoverable after its entry into cells, although the specific biological activity of the re-isolated plasmid DNA is less than that of the parental recombinant plasmid DNA. Therec 1 gene function of the host is necessary for obtaining higher transformation frequencies with recombinant DNA from five different clones. The reduced transformation frequencies seen inrec 1- strain is not all due to a permanent damage to the donor DNA since the recovered recombinant plasmid DNA from such cells can increase the transformation efficiency onrec 1+ strain.
pp 439-447 December 1981
Microbial contamination in cultures of the alga,Scenedesmus acutus raised in outdoor open tanks and also in the processed powder of the alga was monitored; The total bacterial population increased with time during the growth period of six days. When a combination of molasses and carbondioxide was employed as carbon source for this alga, the bacterial load increased to 10 colony forming units/ml. Yeast, molds and also coliforms were quantitated. Drum-drying the algae drastically reduced the bacterial load and storing the algal powder for a period of over 3 months did not increase the bacterial load. Pathogens likeSalmonella andStaphylococcus were not detectable either in the open cultures or in the drumdried algal powder. Although there are not set standards available in literature on the permissible level of the microbial contamination in algal biomass for use in foods, the microbial load appears to be within the limits of permissible levels stipulated by Indian Standard Institution standards for baby foods.
pp 449-456 December 1981
Protein malnutrition in the rat resulted in a reduction in the syntehsis of collagen as determined by changes in the specific and total radioactivity incorporated following a single injection of [3H]-proline. It was also accompanied by a retardation in the maturation of soluble to insoluble collagen. In addition, protein deficiency was accompanied by decreased rates of catabolism of both soluble and insoluble collagen.
pp 457-461 December 1981
The toxicity of the carbamate insecticide carbaryl (Seven√) and its metabolite, 1-naphthol, to four species of fish was studied. The calculated 96 h LC 60 values of carbaryl forCatla catla (Ham.), Anabas testudineus (Bloch),Mystus cavasius (Ham.) andMystus vittatus (Bloch) are 6.4, 6.6, 4.6 and 2.4 ppm respectively and that of 1-naphthol are 4.3,3, 0.33 and 1.1 ppm respectively. The degradation product of the insecticide was found to be more toxic than the parent compound, to all the four species studied.
pp 463-468 December 1981
The present experiments were carried out to further elucidate the mechanism by which dopamine mediates the actions of Y-aminobutyric acid on prolactin release from anterior pituitary following its intraventricular injection in overiectomized conscious rats, Y-Aminobutyric acid significantly suppressed the prolactin levels at 0.1 Μmol concentration while at 4 Μmol dose, the level was elevated. The activity of tyrosine hydroxylase was increased significantly in the anterior pituitary at the lower dose while the higher concentration of Y-aminobutyric acid did not bring about any change in the activity both in the hypothalamus and the anterior pituitary. The results presented suggest that intracellular dopamine in the anterior pituitary may directly inhibit prolactin release; the plasma prolactin level is elevated by Y-aminobutyric acid, by way of either inhibiting dopaminergic tone or possible stimulation of a physiological prolactin releasin g hormone.
Volume 44 | Issue 5
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