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151.
Antimicrobial polypeptides of the human colonic epithelium 总被引:4,自引:0,他引:4
The lumen of the human colon is heavily colonized with microbes, but infections across its epithelial surface are infrequent. To address the hypothesis that antimicrobial polypeptides contribute to the barrier function of colonic epithelial cells, we examined cellular extracts from non-inflamed colonic mucosa using an antimicrobial assay. This approach yielded five polypeptides: three antimicrobials were previously identified as ribosomal polypeptides (L30, S19 and ubiquicidin), and two were members of the histone family (H1.5 and H2B). All exhibited bactericidal activity against Escherichia coli, and with the exception of S19, had been isolated by others based on their potent antimicrobial activity in other cells and tissues. These polypeptides normally reside inside cells and are proposed to contribute to the formation of the functional antimicrobial barrier of the colonic epithelium. 相似文献
152.
In order to evaluate the modulatory effects of manganese, high fat diet fed and alloxan diabetic rats were taken and the changes
in the glucose oxidation, glycerol release and effects of manganese on these parameters were measured from adipose tissue.
An insulin-mimetic effect of manganese was observed in the adipose tissue in the controls and an additive effect of insulin
and manganese on glucose oxidation was seen when Mn2+ was addedin vitro. The flux of glucose through the pentose phosphate pathway and glycolysis was significantly decreased in high fat fed animals.
Although thein vitro addition of Mn2+ was additive with insulin when14CO2 was measured from control animals, it was found neither in young diabetic animals (6–8 weeks old) nor in the old (16 weeks
old). Both insulin and manganese caused an increased oxidation of carbon-1 of glucose and an increase of its incorporation
into14C-lipids in the young control animals; the additive effect of insulin and manganese suggests separate site of action. This
effect was decreased in fat fed animals, diabetic animals and old animals. Manganese alone was found to decrease glycerol
in both the control and diabetic adipose tissue inin vitro incubations. The results of the effects of glucose oxidation, lipogenesis, and glycerol release in adipose tissue of control
and diabetic animals of different ages are presented together with the effect of manganese on adipose tissue from high fat
milk diet fed animals. 相似文献
153.
154.
Vegetative and generative dispersal capacity of field released transgenic aspen trees 总被引:2,自引:0,他引:2
Matthias?FladungEmail author Olaf?Nowitzki Birgit?Ziegenhagen Sandeep?Kumar 《Trees - Structure and Function》2003,17(5):412-416
Transfer of genes by pollen or wind-dispersed seed is considered a main potential risk when field release experiments with transgenic trees are initiated. In Germany, the first release experiment with genetically transformed trees was initiated in 1996. To ensure that the transgenic trees remained in the vegetative phase, the duration of the experiment was limited to 5 years. In total, 457 1-year-old trees including eight transgenic aspen lines carrying either the 35S- rolC or the rbcS- rolC gene construct, and three control clones were transferred to the field. In 1998 and 2000, 12 plants of transgenic lines all carrying the 35S- rolC gene construct formed female flower buds. Furthermore, one young aspen plant identified as a root sucker was observed in 1999 followed by an increasing number of root suckers derived from transgenic and non-transgenic trees in 2000 and 2001. In 2001, the last year of the field trial, 15 root suckers were detected outside the field. In total, 234 root suckers were harvested in 2000 and 2001 and analysed for their transgenic status. More than half of the roots suckers investigated showed the presence of the rbcS- rolC gene construct. We concluded that in addition to the widely accepted generative propagation, vegetative dispersal capacity of transgenic perennial plants is also important and must be included in risk assessment studies. 相似文献
155.
Dasgupta Trisha Banerjee S. Yadav P.K. Rao A.R. 《Molecular and cellular biochemistry》2001,226(1-2):17-26
Numerous reports have revealed an inverse association between consumption of some selective natural products and risk of developing cancer. In the present study the effect of 250 and 500 mg/kg body weight of Spirulina was examined on drug metabolising phase I and phase II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of 7-week-old Swiss albino mice. The implications of these biochemical alterations have been further evaluated adopting the protocol of benzo(a)pyrene induced forestomach and 7,12 dimethylbenz(a)anthracene (DMBA) initiated and croton oil promoted skin papillomagenesis. Our primary findings reveal the Monofunctional nature of Spirulina as deduced from its potential to induce only the phase II enzyme activities associated mainly with carcinogen detoxification. The glutathione S-transferase and DT-diaphorase specific activities were induced in hepatic and all the extrahepatic organs examined (lung, kidney and forestomach) by Spirulina pretreatment (significance level being from p < 0.05 to p < 0.005) except for the low dose treatment in forestomach. With reference to antioxidant enzymes viz., superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and reduced glutathione were increased significantly by both the chosen doses of Spirulina from p < 0.01 to p < 0.005. Chemopreventive response was quantitated by the average number of papillomas per effective mouse (tumor burden) as well as percentage of tumor bearing animals. There was a significant inhibition of tumor burden as well as tumor incidence in both the tumor model systems studied. In the skin tumor studies tumor burden was reduced from 4.86 to 1.20 and 1.15 by the low and high dose treatment respectively. In stomach tumor studies tumor burden was 2.05 and 1.73 by the low and high doses of Spirulina treatment against 3.73 that of control. 相似文献
156.
The genotoxic effect of hookah smoke was investigated on somatic chromosomes of 35 occupationally nonexposed male hookah smokers. These were compared with an equal number of nonsmokers matched with respect to age, sex, drug intake, if any, and socio-economic status. The mitotic index (MI), chromosomal aberrations (CA), sister chromatid exchanges (SCE) and satellite associations (SA) were analysed. All the parameters showed a significant increase (p < 0.01) in the smokers compared with control individuals, viz MI, 3.88-5.41; CA, 0.94-2.22; SCE, 3.59-5.66; and SA, 5.2-8.65. A distinct time and dose effect relationship was observed. Hookah smoke is thus, both clastogenic and genotoxic for human beings. 相似文献
157.
Kovala-Demertzi D Yadav PN Demertzis MA Coluccia M 《Journal of inorganic biochemistry》2000,78(4):347-354
The reactions of Na2PtCl4 with pyridine-2-carbaldehyde and 2-acetyl pyridine N(4)-ethyl-thiosemicarbazones, HFo4Et and HAc4Et respectively, afforded the complexes [Pt(Fo4Et)Cl], [Pt(HFo4Et)2]Cl2, [Pt(Fo4Et)2] and [Pt(Ac4Et)Cl], [Pt(HAc4Et)2]Cl2 x 2H2O, [Pt(Ac4Et)2]. The new complexes have been characterized by elemental analyses and spectroscopic studies. The crystal structure of the complex [Pt(Ac4Et)Cl] has been solved. The anion of Ac4E coordinates in a planar conformation to the central platinum(II) through the pyridyl N, azomethine N and thiolato S atoms. Intermolecular hydrogen, non-hydrogen bonds, pi-pi and weak Pt-pi contacts lead to aggregation and a supramolecular assembly. The cytotoxic activity for the platinum(II) complexes in comparison to that of cisplatin and thiosemicarbazones was evaluated in a pair of cisplatin-sensitive and -resistant ovarian cancer cell lines A2780 and A2780/Cp8. The platinum(II) complexes showed a cytotoxic potency in a very low micromolar range and were found able to overcome the cisplatin resistance of A2780/Cp8 cells. 相似文献
158.
A. Bhattacharya Monika T. Anand Jayshree Paul Nagendra Yadav S. Bhattacharya 《The Journal of eukaryotic microbiology》1998,45(2):28S-33S
Entamoeba histolytica, the protozoan parasite, is the causative agent of amoebiasis. The degree of virulence, as inferred from invasiveness, of potentially pathogenic strains may be regulated by both host and parasite factors that determine the gut environment. One such factor that plays an important role is the bacterial flora in the gut. Previous studies have clearly shown that bacterial flora is an important determinant of virulence in E. histolytica. However, the exact nature of changes induced in E. histolytica in response to bacteria and their role in virulence is not clear. In this study the levels of a number of molecules potentially important in virulence mechanisms were determined in E. histolytica cells grown with and without normal human bacterial flora, using enzyme-linked immunosorbent assay. Significant changes were observed only after the E. histolytica cells had been adapted to grow with bacterial flora for a number of generations, and not in short term culture. 相似文献
159.
Ajit Kumar Shasany Suman P. S. Khanujia Sunita Dhawan Usha Yadav Srikant Sharma Sushil Kumar 《Journal of biosciences》1998,23(5):641-646
Media and incubation conditions have been defined for highly efficient regeneration of shoots from internode explants of slow
and fast growing cultivars ofMentha arvensis. Internodal segments excised from thein vitro raised shoots were inoculated on the MS medium supplemented with combinations of 5 concentrations of l-napthalene acetic
acid (NAA) and 3 concentrations of 6-benzyl amino purine (BAP). The media containing 2 μg ml−1 NAA, 10 Μg ml−1 BAP and 1 μg ml−1 NAA, 5 μg ml−1 BAP proved best for shoot regeneration and growth responses on cv Himalaya and cv Kalka explants, respectively. In 12 weeks
time, on average one explant of cv Himalaya produced about 200 shoots and that of cv Kalka produced about 180 shoots. The
Himalaya explants required higher concentrations of NAA and BAP for high efficiency proliferation as compared to the Kalka
explants. The experiments demonstrated that internodal tissue inMentha arvensis can be induced to obtain direct shoot regenerants with high efficiency. The analysis of the RAPD profiles of 100 regenerated
plantlets each of cv Himalaya and Kalka showed more than 99.9% homogeneity in bands with respect to the parents. 相似文献
160.