Blue guaran (a chromophore-labeled galactomannan) as a reagent for lectins

A new reagent (blue guaran) for quantitative estimation of lectins, has been derived from a galactomannan (guaran). When the lectin solution is added to an aqueous solution of blue guaran, dye-bound guaran is precipitated from the solution. The difference in absorbance of the blue guaran solution before and after the addition of lectin solution is proportional to the amount of lectin present in the sample. The method of preparation of blue guaran, its spectral characteristics and effect of pH on precipitation have also been described. It gives a simple colorimetric method for the estimation of galactose-specific lectins.     

Wastewater: A Potential Bioenergy Resource

Wastewaters are a rich source of nutrients for microorganisms. However, if left unattended the biodegradation may lead to severe environmental hazards. The wastewaters can thus be utilized for the production of various value added products including bioenergy (H₂ and CH₄). A number of studies have reported utilization of various wastewaters for energy production. Depending on the nature of the wastewater, different reactor configurations, wastewater and inoculum pretreatments, co-substrate utilizations along with other process parameters have been studied for efficient product formation. Only a few studies have reported sequential utilization of wastewaters for H₂ and CH₄ production despite its huge potential for complete waste degradation.     

Retention of enzymatic activity by N-terminal domain (1-78) T4-lysozyme: expression of synthetic DNA in Escherichia coli

DNA of 235 b.p. coding for N-terminal domain (1-78) T4-lysozyme was synthesized and cloned by ligating twelve synthetic fragments with a linearized plasmid pUCE8 followed by transformation. On expression in E. coli strain JM103 cells, colonies containing the synthetic DNA were found to be lytic. On purification, clone ptly. 23-5 was found to contain polypeptide (M.W. 10,500), corresponding to N-terminal domain, its dimeric and aggregate form. It was identified by amino acid sequence analysis of the dimeric form.     

Studies on the C-24 configurations of Δ7-sterols in theseeds of Cucurbita maxima

Uncertainties surrounding the structures of the Δ⁷-sterols in the seeds of Cucurbita maxima have been resolved. Seven components were found by TLC, GLC, HPLC, mass spectrometry and ¹H NMR. They were 24β-ethyl-5α-cholesta-7,22,25(27)-trien-3β-ol, 24β-ethyl-5α-cholesta-7,25(27)-dien-3gb-ol, avenasterol, spinasterol, 24-dihydrospinasterol, 24ζ-methyllathosterol and 25(27)-dehydrofungisterol. The ¹H NMR spectra indicated that the sterols with an ethyl substituent at C-24 occurred in the absence of their C-24 epimers. This seems to be the first instance of the detection of 25(27)-dehydrofungisterol in a higher plant.     

Purification and characterization of metallothionein from liver of cadmium exposed Rhesus monkeys (Macaca mulatta)

Metallothionein (MT) a low molecular weight, Cd-binding, cysteine rich, cytosolic protein has been isolated, purified and characterized from cadmium exposed Rhesus monkeys maintained on protein calorie malnourished (PCM) diet. Metallothionein was resolved into three isoforms i.e. MT_a, MT_b and MTV_c. The ratio of Cd, Zn and Cu varied in these isometallothioneins. MT_c was the major isometallothionein. UV Spectra of MT_c revealed the presence of mercaptide bonds and absence of aromatic amino acids. These observations were further confirmed by amino acid analysis of MT_c which demonstrated high cysteine content (22.6) followed by serine, glycine and lysine. The molecular weight of MT_c as determined by gel filtration and amino acid analysis was 13000 and 6398 daltons respectively. This demonstrates that MT_c is a non-globular ellipsoid polypeptide. MT_c showed a unique property of binding selenium. Monkey liver metallothionein was immunologically identical with human metallothionein. All the characteristics of MT_c obtained in the present study reveal a similarity between monkey and human metallothionein probably due to closer phylogenetic relationship between the two species.     

Suppression of ouabain-insensitive K-ATPase activity in rabbit nephron segments during chronic hyperkalemia

Recently, we demonstrated that an ATPase stimulated by K (and not inhibited by ouabain, Na-K-ATPase inhibitor) is present in the connecting tubule (CNT) and collecting duct segments of the rabbit. In this study, we determined the effects of high- and low-K diet on K-ATPase activity in the CNT and collecting duct segments of rabbit. One group of animals was given a low-K diet (34 mEq/kg diet) and the other group was given a high-K diet (700 mEq/kg diet) for 1 week. K-ATPase activity was measured by a microfluorometric assay in which ATP hydrolysis is coupled to oxidation of NADH. Low-K animals had plasma K = 3.1 +/- 0.2 as compared with 5.5 +/- 0.5 mEq/l in high-K animals. Low-K animals had significant K-ATPase activity in CNT, CCD (cortical collecting duct) and MCD (medullary collecting duct). On the other hand, K-ATPase activity in all 3 segments from high-K animals was not significantly different from zero. These results support a hypothesis that chronic K loading suppresses the ouabain-insensitive K-ATPase in the distal nephron.     

Immobilization of lipase from Candida cylindraceae and its use in the synthesis of menthol esters by transesterification.

Lipase (EC 3.1.1.3) from Candida cylindraceae has been immobilized by the cellulose-titanium chloride method, and on EP-400 polyethylene, with and without glutaraldehyde crosslinking, to give active preparations when assessed by their ability to catalyse the hydrolysis of tributyrin. In both cases, the use of glutaraldehyde crosslinking was shown to improve the stability of the preparations for repeated use. The lipase immobilized on EP-400 polyethylene was found to be effective in transesterification using tributyrin or triacetin as acyl donors with l-menthol as acceptor. The production of methyl butanoate and of methyl acetate using this immobilized preparation was in each case enhanced in the presence of Amberlite IR 47 Anion exchange resin (OH form).     

An improved method of plant megabase DNA isolation in agarose microbeads suitable for physical mapping and YAC cloning

The isolation of high quality megabase DNA from plant cells that is susceptible to a variety of molecular reagents is a critical first step in the physical analysis of complex genomes. A method for the isolation of such DNA by encapsulating plant protoplasts in agarose microbeads is presented. In comparison with the conventional agarose plug method, microbeads provide a dramatic increase in the surface area yielding megabase DNA that can be treated essentially as an aqueous DNA solution. Examples of the utility of DNA prepared by this technique for physical mapping, partial restriction enzyme digestion and cloning of large inserts as YACs are presented.