首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 923 毫秒
1.
Indian tribals use insects in a variety of ways. Species containing valuable protein, easily digestible fats, and considerable amounts of vitamins and minerals are consumed; others serve as raw material for folk remedies. Such uses need to be documented, because tribal communities are increasingly discarding their age-old practices. Research into this field can benefit India and the rest of the world in several ways. Traditional communities need to be shown to appreciate the value of their customs and that to look after their environment (lest many of the useful insects will disappear) is not a luxury, but a necessity. Moreover, studying food insects and therapeutically important species can lead to economic spin-offs and would allow countries like India to develop ways to sustainably use this abundant natural resource.  相似文献   

2.
3.
4.
5.
6.
Three biological settings involving self-organization performed by the Turing-Child field inside a sphere and on its surface are considered. In the first setting the interior of a sphere made up of cells communicating via gap junctions is considered. It is suggested that the Turing-Child self-organization is the cause of radial polarization, the first differentiation of an early mammalian embryo. In the second setting, the Turing example of gastrulation of a hollow cellular sphere is considered. It is shown that Child's experimental patterns are predicted and explained by the Turing-Child theory. The third setting is the interior of a biological cell, and it is suggested that it is the self-organization of the Turing-Child field that causes the formation of the mitotic spindle.  相似文献   

7.
Dr. George Lister of the University of Texas Southwestern Medical Center delivered the Lee E. Farr Lecture on Student Research Day on May 9, 2011. This day focused on the dissertation work of Yale School of Medicine MD students, whose research opportunities for prospective physicians were recently examined and critiqued by Yale's Committee to Promote Student Interest in Careers as Physician Scientists. Lister's talk served to highlight the importance of communication between the laboratory and the clinic in optimizing diagnostics and treatments, effectively affirming the validity of the Committee's objectives.  相似文献   

8.
Isolates of the phytopathogenic ascomycete Ascochyta rabiei (Pass.) Labr. were stained with the DNA-specific fluorochrome 4',6-diamidino-2-phenylindole (DAPI) and compared for differences in number of nuclei per pycnidiospore and the ploidy level. Microscopic analyses revealed that within the examined isolates five different combinations of cell number and number of nuclei in spores exist. A one-celled spore may contain one, two and four nuclei, respectively, and in the case of two-celled spores there exist types with one and two nuclei in one cell. Microfluorometric analyses of wild types and benomyl-treated isolates revealed differences in ploidy level among the wild types.  相似文献   

9.
Three biological settings involving self-organization performed by the Turing-Child field inside a sphere and on its surface are considered. In the first setting the interior of a sphere made up of cells communicating via gap junctions is considered. It is suggested that the Turing-Child self-organization is the cause of radial polarization, the first differentiation of an early mammalian embryo. In the second setting, the Turing example of gastrulation of a hollow cellular sphere is considered. It is shown that Child's experimental patterns are predicted and explained by the Turing-Child theory. The third setting is the interior of a biological cell, and it is suggested that it is the self-organization of the Turing-Child field that causes the formation of the mitotic spindle.  相似文献   

10.
11.
Tetcyclacis, a norbornanodiazetine plant growth retardant, used at 10 mg · L–1 (36 m), caused greater growth inhibition in the shoots of fenugreek (Trigonella foenum-graecum L.) seedlings (60%) than in the roots (30%), compared with control. This greater retardation was reversed by a supplement of gibberellin (200 mg · L–1). The total sterol composition of control and treated seedlings was analyzed and quantified. In the roots especially, treatment of seedlings with tetcyclacis resulted in a modification of the sterol profile, leading to an accumulation of 14-methyl sterols, presumably as a consequence of the inhibition of cytochrome P-450-dependent obtusifoliol 14-demethylase. In addition, tetcyclacis caused a significant increase in the cholesterol content of the roots: 38.1% of total sterols against 3.7% in the control roots. However, tetcyclacis was shown to be an ineffective inhibitor of the S-adenosyl-l-methionine (Adomet): cycloartenol-C24-methyltransferase (EC 2.1.1.41) in fenugreek microsomes indicating that cholesterol accumulation does not result from the inhibition of the sterol side chain-alkylating enzyme. Moreover, this accumulation was shown to be concomitant with a significant decrease of the sapogenin content in the treated roots. This last result is discussed with respect to the current proposed pathway by which cholesterol is metabolized to saponins.Abbreviations GA gibberellin - PGR plant growth regulator - GA3 gibberellin acid - FW fresh weight(s) - DW dry weight(s) - Adomet-CMT S-adenosylmethionine-cycloartenol-C24-methyltransferase - GC gas chromatography - TLC thin layer chromatography - MS mass spectroscopy - FS free sterol(s) - SE steryl ester(s) - SG steryl glycoside(s) - ASG acylated steryl glycosides - SAM S-adenosylmethionine  相似文献   

12.
Summary The present study describes the growth of Pseudomonas putida cells (ATCC 33015) in batch and continuous cultures on two toxic substrates; toluene and m-toluic acid as sole carbon and energy sources. In fed-batch cultures on m-toluic acid up to 3.55 g cell dry weight/1 were achieved with a maximal specific growth rate (max) of 0.1 h-1. The average cellular yield was 1.42 g cell dry weight/g m-toluic acid utilized. When liquid toluene was added to shake-flask cultures in the presence of 0.7 g/1 m-toluic acid, the average cellular yield obtained was 1.3 g cell dry weight/g toluene utilized and the max was 0.13 h-1. Growth on toluene vapour in the presence of 0.7 g/l m-toluic acid in batch cultures resulted in a cellular yield of 1.28 g cell dry weight/g toluene utilized, with growth kinetics almost identical to those with liquid toluene (max liquid=0.13 h-1, max vapour=0.12 h-1). The maximal biomass concentration was 3.8 g cell dry weight/l, obtained in both cases after 100 h of incubation. Pseudomonas putida was grown in a chemostat initially on 0.7 g/l m-toluic acid and vapour toluene and then in the steady state on toluene as the sole source of carbon and energy. Toluene was added continuously to the culture as vapour with the inflowing airstream. Chemostat cultures could be maintained at steady state for several months on toluene. The maximal biomass concentration obtained in the chemostat culture was 3.2 g cell dry weight/l. The maximum specific growth rate was 0.13 h-1, with a cellular yield of 1.05 g cell dry weight/g toluene utilized. Approximately 70% of the toluene consumed was converted into biomass, and the remainder was converted to CO2 and unidentified byproducts.  相似文献   

13.
14.
15.
16.
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to examine the polypeptide patterns of rat liver rough and smooth endoplasmic reticulum (ER) membrane fractions stripped of ribosomes. Approximately 67 polypeptides were resolved from the rough ER membrane fraction. The polypeptide pattern of the smooth ER membrane fraction was similar to that of the rough ER membrane fraction, but exhibited substantially lower amounts of some seven polypeptides. Three of these polypeptides, of apparent molecular weights 63,000, 65,000, and 87,000, were of particular interest, as they could not be ascribed to contamination of stripped rough ER membrane fractions by residual ribosomal polypeptides. Conditions of treatment with low concentrations of trypsin were established that markedly diminished the capacity of the stripped rough ER membrane fraction to bind ribosomes in vitro and that also effected a partial detachment of ribosomes from nonstripped rough ER membranes; the results of electrophoretic analyses of rough ER membrane fractions treated in these manners are described. Comparison of the polypeptide patterns of guinea pig, mouse, and rabbit liver ER membrane fractions with rat liver ER membrane fractions revealed considerable variations in the distribution of the polypeptides of 63,000, 65,000, and 87,000 molecular weight among the ER membrane fractions of these species. The combined results of these studies indicate that the polypeptide of 87,000 molecular weight, although particularly sensitive to attack by trypsin, is not involved in the binding of ribosomes to the rough ER membrane fraction. Studies by others (cf. Kreibich, G., Grebenau, R., Mok, W., Pereyra, B., Rodriguez-Boulan, E., and Sabatini, D. D. (1977) Fed. Proc. 36, 656) have implicated the polypeptides of 63,000 and 65,000 molecular weight in this process. The patterns of phosphorylated polypeptides of rough and smooth ER membrane fractions of rat and mouse liver were also examined, using labeling in vivo with sodium [32p]phosphate or in vitro with [gamma-32P]ATP. Approximately 25 phosphorylated components were resolved by electrophoresis in the ER membrane fractions of both species. Evidence is presented that suggests that the great majority of these components are phosphopolypeptides. Differences were noted in the patterns of phosphorylation produced by in vivo and in vitro labeling; minor differences were also observed between the patterns of phosphorylation of the rough and smooth ER membrane fractions in either situation. The overall results afford an indirect approach toward evaluating the possible involvement of specific rough ER membrane polypeptides in ribosome-binding and reveal that liver ER membranes contain a substantially greater number of phosphorylated polypeptides thatn previously reported.  相似文献   

17.
18.
19.
20.
pH-sensitive nonionic surfactant vesicles (niosomes) by polysorbate-20 (Tween-20) or polysorbate-20 derivatized by glycine (added as pH sensitive agent), were developed to deliver Ibuprofen (IBU) and Lidocaine (LID). For the physical-chemical characterization of vesicles (mean size, size distribution, zeta potential, vesicle morphology, bilayer properties and stability) dynamic light scattering (DLS), small angle X-ray scattering and fluorescence studies were performed. Potential cytotoxicity was evaluated on immortalized human keratinocyte cells (HaCaT) and on immortalized mouse fibroblasts Balb/3T3. In vivo antinociceptive activity (formalin test) and anti-inflammatory activity tests (paw edema induced by zymosan) in murine models were performed on drug-loaded niosomes. pH-sensitive niosomes were stable in the presence of 0 and 10% fetal bovine serum, non-cytotoxic and able to modify IBU or LID pharmacological activity in vivo. The synthesis of stimuli responsive surfactant, as an alternative to add pH-sensitive molecules to niosomes, could represent a promising delivery strategy for anesthetic and anti-inflammatory drugs.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号