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1.
Vinod Kumar 《Chronobiology international》1986,3(3):165-170
Groups of photosensitive, unstimulated or stimulated, male blackheaded buntings were subjected to photoregimes of 15 hr of green light of three intensities and 9 hr of dark per day. In some groups green light was interrupted with 90 min of bright fluorescent light at different times in the subjective day. While gonads did not develop or regressed in some groups, birds in others behaved as if exposed to long daylengths. The results besides suggesting the involvement of endogenous circadian rhythm during initiation and maintenance of gonadal growth indicate that the reproductive rhythms are entrained and induced by environmental photoperiod. 相似文献
2.
The production of d-aminoacylase by Alcaligenes denitrificans and Alcaligenes faecalis has been studied. The enzyme was inducibly produced and N-acetyl-d-leucine and N-acetyl-d-valine were the most effective inducers. d-methionine, d-valine, d-phenylalamine and d-leucine were produced by the enzymic hydrolysis of the appropriate N-acetyl-d-amino-acids with whole cell biomass. The hydrolysis of N-acetyl-d-methionine by A. denitrificans and N-acetyl-d-valine by A. faecalis was preferential. Maximum yields of d-methionine and d-valine were 94.3 and 84.7% at a specific product formation rate of 20.10 and 19.19 μmol min−1 mg−1 of wet cells at 20 mM substrate concentration and 5 mg ml−1 of cell density. 相似文献
3.
Polysaccharides excreted by cowpea Rhizobium strains JLn(c) and RA-1 were mixtures of complex acidic exopolysaccharides and low molecular weight neutral glucans. These polymers were fractionated using gel filtration chromatography. Purified fractions of the acidic heteropolymer reacted with peanut agglutinin to give precipitin bands when subjected to Ouchterlony gel diffusion. The acidic exopolysaccharide was found to contain mainly glucose, galactose, glucuronic acid, mannose and fucose. The non-carbohydrate substituents of the acidic heteropolymer were pyruvate, acetate and uronate which were identified by infrared and proton nuclear magnetic resonance spectroscopy as well as by chemical analysis.Abbreviations EPS
Extracellular polysaccharide
- YEM
yeast extract mannitol
- PNA
peanut agglutination
-
1H-NMR
proton nuclear magnetic resonance 相似文献
4.
5.
Design of liposome to improve encapsulation efficiency of gelonin and its effect on immunoreactivity and ribosome inactivating property 总被引:1,自引:0,他引:1
Anis Alam S. R. K. Bhuri Anil K. Mavila Vinod Singh 《Molecular and cellular biochemistry》1992,112(2):97-109
Gelonin, purified from the seeds of Gelonium multiflorum, using cation-exchange and gel-filtration chromatography was characterised for its purity, homogeneity and molecular weight by reverse-phase HPLC (RP-HPLC) and SDS-PAGE analysis. The HPLC purified gelonin was used for entrapment studies in the liposomes. Liposomes were prepared by reverse phase evaporation (REV) technique using three different types of lipid composition in the same molar ratio. The method resulted in 75–80% entrapment efficiency of gelonin in the liposomes. Entrapped and unentrapped gelonin was characterized for physico-chemical, immunochemical and biological properties. The immunoreactivity of entrapped gelonin was fully preserved but the ribosome-inactivating property was slightly inhibited. The method involved mild conditions, highly reproducible and the liposomes produced appeared to be stable for several months. It has important implications in the development of cell type specific cytotoxic agents where a chemical cross-linking is involved which significantly inhibits both immunoreactivity and ribosome-inactivating ability of the toxin. 相似文献
6.
From the hot petrol extract of Piper cubeba ftuits, six lignans were isolated. Two of these, which have been obtained from a natural source for the first time, have been characterized as (2R,3R)-2-(3″,4″,5″-trimethoxybenzyl)-3-(3′,4′-methylenedioxybenzyl)-1,4-butanediol [(?)-dihydroclusin] and (3R,4R)-3,4-bis-(3,4,5-trimethoxybenzyl)tetra-hydro-2-furanol [(?)-cubebinin]. (?)Cubebin, (?)-hinokinin, (?)-clusin and (?)-dihydrocubebin were also found in this plant. Only (?)-cubebin has been reported so far from this source. 相似文献
7.
K.A. Prabhu 《Enzyme and microbial technology》1985,7(6):279-282
Dextranase (1,6-α-d-glucan 6-glucanohydrolase, EC 3.2.1.11) from Penicillium aculeatum culture has been immobilized on a bentonite support. The matrix-bound enzyme could be stored as acetone-dried powder or as a suspension in acetate buffer, pH 5.6, for about three weeks at 4°C without any loss of activity. There was no change in the specific activity of the enzyme on immobilization and the enzyme yield was 0.1–0.6 mg/g bentonite matrix. In the presence of sucrose, thermal stability of the immobilized enzyme was high and the bound enzyme could be used for about six cycles. 相似文献
8.
Callus cultures were established from seedling root tips of mungbean (Vigna radiata (L.) Wilczek var. radiata) cv. K 851. The growing calli were exposed to increasing concentrations of thioproline — an analog of proline, in the medium. A concentration of 3.0 mM thioproline completely inhibited the growth of the cells. However, after 25 days incubation 5 cell clones were obtained which could grow on this concentration of thioproline. Out of them one vigorously growing cell clone was further characterized. This selected clone contained higher endogenous levels of free proline (5 fold) and K+ (1.5 fold) and exhibited elevated tolerance, not only to thioproline but also to exogenously applied NaCl in the growth medium, as compared to the normal sensitive callus cells. Higher endogenous levels of free proline and K+ appear to impart dual resistance to thioproline and NaCl to the selected cell strain. 相似文献
9.
The DNP derivative of sonicate antigens of the H37Ra strain ofMycobacterium tuberculosis (Ra-DNP) is known to induce marked B-cell proliferation. In order to understand whether B-cell proliferation in response
to Ra-DNP was antigen driven or represented a non-specific mitogenic effect of Ra-DNP, the effect of Ra-DNP was compared with
that of lipopolysaccharide a potent B-cell mitogen. Parameters used for comparison were (i) thymidine incorporation, (ii)
viable cell counts, (iii) amount of lg secreted, (iv) isotype profile of Ig released and (v) cell cycling pattern of B-cells
in culture. Overall the effect of Ra-DNP was found to be essentially similar to that of lipopolysaccharide for all parameters
examined. Yet quantitatively, the effect of the former was always relatively poorer. At optimal doses, the effect of Ra-DNP
ranged from 50 to 70% of the lipopolysaccharide effect in different assays. These results suggest that Ra-DNP may have a B-cell
mitogenic effect similar to the effect of lipopolysaccharide, but all B-cells may not respond to Ra-DNP. 相似文献
10.
Since the positive charge on the lysine residues plays an important role in the receptor recognition ability of oLH, the hormonotoxin has been synthesised with the use of 2-iminothiolane HC1 (2IT) and N-Succinimidyl-3-(2-pyridyldithio)-propionate (SPDP). The oLH activated with 2IT (oLH-10) was then mixed with SPDP activated gelonin (gelonin-30) in order to obtain a oLH-S-S-gelonin hormonotoxin. The conjugation mixture containing hormonotoxin was purified by gel-filtration chromatography according to the molecular weight and a complete physico-chemical, immunochemical and biochemical analysis were performed. The linkage occured through the -NH2 groups of -subunit of oLH as judged from RP-HPLC analysis. A 11 (oLH:gelonin) molar ratio was obtained when determined with the use of several techniques. The hormonotoxins retained substantial receptor binding, steroidogenic activity and immunoreactivity. The competitive displacement analysis indicate that the binding occurs via the hormone part leaving the gelonin free which was probed with the gelonin antibodies. The presently described (C150A-02, C160A-02 and C170A-02) hormonotoxins exhibited higher receptor binding and toxicity to the target cells than the hormonotoxins prepared with the use of SPDP only. Therefore it is concluded that higher receptor binding and cytotoxicity may be due to the retention of positive charge on the lysine residues of oLH which was preserved during the conjugation process.Abbreviations BSA
Bovine Serum Albumin
- CMC
Carboxy methyl Cellulose
- DTT
Dithiothreitol
- DMEM
Dulbeco's Modified Eagle's Medium
- DTNB
Ellman's reagent [5,5-dithio-bis-(2-nitrobenzoic acid)]
- EDTA
Ethylenediaminetetraacetic acid
- FPLC
Fast Protein Liquid Chromatography
- FCA
Freund's Complete Adjuvant
- FCS
Fetal Calf Serum
- Gelonin-30
Gelonin modified by SPDP
- GnRH
Gonadotropin-Releasing Hormone
- Gelonin-SPDP
SPDP modified derivative of gelonin
- HEPES
(N-[2-hydroxyethyl] piperazine-N-[-2-ethanesulphonic acid])
- IFA
Incomplete Freund's Adjuvant
- 2IT
2-Iminothiolane
- IODOGEN
1,3,4,6-tetrachloro 3,6-diphenylglycouril
- oLH
Ovine Luteinizing Hormone
- oLH-SPDP
SPDP modified derivative of oLH
- oLH-10
oLH modified by 2IT
- oLH2IT
Molar ratio of oLH and 2IT
- PDP
2-Pyridyl-dithiopropionate
- PAP
Pokeweed Antiviral Protein
- RIP
Ribosome Inactivating Protein
- RP-HPLC
Reverse-Phase High Performance Liquid Chromatography
- RPMI
Roswell Park Memorial Institute
- RIA
Radioimmunoassay
- RRA
Radioreceptor Assay
- SPDP
N-Succinimidyl-3(2-pyridyldithio)propionate
- SDS-PAGE
Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis
- TCA
Trichloroacetic acid
- TFA
Trifluroacetic acid 相似文献