Transport of amino acids in gamma-glutamyl transpeptidase-implanted human erythrocytes

gamma-Glutamyl transpeptidase purified from hog kidney cortex was implanted in the human erythrocyte membrane by incubation of erythrocytes at 37 degrees c with gamma-glutamyl transpeptidase-incorporated dipalmitoyl phosphatidylcholine vesicles. Membranes prepared from these implanted cells exhibited 4- to 5-fold increase in gamma-glutamyl transpeptidase activity. The association/insertion of gamma-glutamyl transpeptidase into erythrocyte membrane was further demonstrated by antibody to gamma-glutamyl transpeptidase. Implantation of gamma-glutamyl transpeptidase into erythrocyte membrane led to stimulation of uptake of glutamate and alanine, which are normally transported at a slow rate in human erythrocytes. The uptake of these amino acids in the implanted system was inhibited by inhibitors (serine-borate and azaserine) of transpeptidase activity as well as by antibody to gamma-glutamyl transpeptidase. These results in the implanted human erythrocytes demonstrate that gamma-glutamyl transpeptidase enzyme can mediate the translocation of amino acids and provide further evidence in support of its postulated role in the transport of amino acids in natural membranes.     

Histopathology of Mycotoxicosis produced in Swiss albino mice by metabolites of some fungal isolates.

Of 199 fungal cultures isolated from some of the common cereals collected from different parts of Uttar Pradesh and Madhya Pradesh, 70 produced toxic metabolites. Of the 70 fungi isolated, 59 produced toxins which caused visible lesions in livers, kidneys, and spleens but did not cause mortality. Toxicity, graded in terms of the mortality rate and the extent of lesions in livers, kidneys, and spleens, was found to be highest in various species of Aspergillus (40%), followed by Chaetomium spp. (31%).     

Experimental intestinal histoplasmosis of hamsters

Summary In order to elicit primary intestinal histoplasmosis, hamsters and mice were given the infective agent by drinking a suspension of yeast cells, eating infected mouse liver, and through injection into the wall of the lumen of the cecum after laparotomy.Histologic examination and isolation by cultures were made, maximally 6 weeks after infection.No clear-cut histoplasmic primary complex in the intestine was confirmed, but a fungus disease was achieved in a few animals, suggesting the intestinal tract as a possible portal of entrance of the infection.Some of the animals fed with a fungus suspension developed primary pulmonary lesions, a remarkable fact to be considered in evaluation of feeding experiments.The lack of confirmed evidence of intestinal primary lesions as contrasted with the constant demonstration, when searched for, of pulmonary lesions, would suggest that the intestinal tract should not be considered a major portal of entrance in histoplasmosis.This project was supported in part by Grant 986 from the National Institutes of Health.     

The CDC20 gene product of Saccharomyces cerevisiae, a beta-transducin homolog, is required for a subset of microtubule-dependent cellular processes.

Previous analysis of cdc20 mutants of the yeast Saccharomyces cerevisiae suggests that the CDC20 gene product (Cdc20p) is required for two microtubule-dependent processes, nuclear movements prior to anaphase and chromosome separation. Here we report that cdc20 mutants are defective for a third microtubule-mediated event, nuclear fusion during mating of G1 cells, but appear normal for a fourth microtubule-dependent process, nuclear migration after DNA replication. Therefore, Cdc20p is required for a subset of microtubule-dependent processes and functions at multiple stages in the life cycle. Consistent with this interpretation, we find that cdc20 cells arrested by alpha-factor or at the restrictive temperature accumulate anomalous microtubule structures, as detected by indirect immunofluorescence. The anomalous microtubule staining patterns are due to cdc20 because intragenic revertants that revert the temperature sensitivity have normal microtubule morphologies. cdc20 mutants have a sevenfold increase in the intensity of antitubulin fluorescence in intranuclear spindles compared with spindles from wild-type cells, yet the total amount of tubulin is indistinguishable by Western immunoblot analysis. This result suggests that Cdc20p modulates microtubule structure in wild-type cells either by promoting microtubule disassembly or by altering the surface of the microtubules. Finally, we cloned and sequenced CDC20 and show that it encodes a member of a family of proteins that share homology to the beta subunit of transducin.     

Gibberellic acid biosynthesis from whey and simulation of cultural parameters

This article examines the potential of lactose from whey permeate as a substrate for gibberellic acid production. In addition, the paper reports the derivation of mathematical models which simulate the various fermentation conditions to predict precise values. Of the five Fusarium moniliforme isolates screened for their ability to synthesize the gibberellic acid, F. moniliforme-1 proved to be the best strain (670 mg gibberellic acid/l) when fermentation was carried out at 28°C for 12 days. The product started to accumulate at the end of maximum growth phase (day 9) and continued until the curve reached a plateau (day 12). From the observed data and expected values, a temperature range of 27–30°C, pH range of 3.5–5.5 and an inoculum level of 10–12.5% (v/v) were considered optimal for attaining the highest product yield. However, nitrogen sources supplemented in whey permeate medium suppressed the ability of the culture under study to synthesize metabolite and utilize lactose.     

Growth and betaine formation in Medicago sativa tissue cultures

Static and suspension tissue cultures of Medicago sativa were initiated from sterile seedlings, excised roots and aerial portions of the seedlings. Flask suspension cultures containing chlorophyll were also established. The various tissues were harvested after 30 days, growth rates were determined, and the tissue was later lyophilized. The lyophilized tissues from various batches were extracted separately with 70% EtOH. The betaine mixture was isolated from these extracts and from seeds of the plant as their tetraphenylborate salts. The betaines were separated from the latter complex via ion exchange and column chromatography and were identified by standard procedures. All of the tissues, regardless of origin, produced choline. Only chlorophyllous tissue biosynthesized stachydrine.     

A triterpenediol from <Emphasis Type="Italic">Boswellia serrata</Emphasis> induces apoptosis through both the intrinsic and extrinsic apoptotic pathways in human leukemia HL-60 cells

A triterpenediol (TPD) comprising of isomeric mixture of 3α, 24-dihydroxyurs-12-ene and 3α, 24-dihydroxyolean-12-ene from Boswellia serrata induces apoptosis in cancer cells. An attempt was made in this study to investigate the mechanism of cell death by TPD in human leukemia HL-60 cells. It inhibited cell proliferation with IC₅₀ ∼ 12 μg/ml and produced apoptosis as measured by various biological end points e.g. increased sub-G0 DNA fraction, DNA ladder formation, enhanced AnnexinV-FITC binding of the cells. Further, initial events involved massive reactive oxygen species (ROS) and nitric oxide (NO) formation, which were significantly inhibited by their respective inhibitors. Persistent high levels of NO and ROS caused Bcl-2 cleavage and translocation of Bax to mitochondria, which lead to loss of mitochondrial membrane potential (Δψ_m) and release of cytochrome c, AIF, Smac/DIABLO to the cytosol. These events were associated with decreased expression of survivin and ICAD with attendant activation of caspases leading to PARP cleavage. Furthermore, TPD up regulated the expression of cell death receptors DR4 and TNF-R1 level, leading to caspase-8 activation. These studies thus demonstrate that TPD produces oxidative stress in cancer cells that triggers self-demise by ROS and NO regulated activation of both the intrinsic and extrinsic signaling cascades.