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 78 毫秒
1.
The culture supernatant ofPseudomonas tralucida (Ptm+ strain) produces an agent which can emulsify the insecticide hexachlorocyclohexane (HCH), which was secreted by resting cells. Emulsifying agent is most active with -HCH, and has some activity towards other chlorinated and phosphatic insecticides. The emulsifier is a heat stable macromolecule and associated with growth of the organism on -HCH.  相似文献   

2.
Summary The metabolic formation of ,-tridecanedioic acid via n-tridecanoic acid and via ,-tridecanediol from n-tridecane in the mutant S 76 of Candida tropicalis was studied. It was found that resting cells of S 76 produced ,-tridecanediol from n-tridecane.With n-tridecanol as substrate, the ,-diol could also be detected. The mutant S 76 was able to produce ,-tridecanedioic acid using either n-tridecanol or n-tridecanoic acid as the sole carbon source. Quantitative changes in the concentration of -hydroxy tridecanoic acid and other intermediates were recorded during the formation of ,-dioic acid.The results confirm the existence of two metabolic pathways mentioned above in the course of ,-dioic acid formation from odd n-alkane in the mutant S 76 of C. tropicalis.  相似文献   

3.
Summary Detailed restriction enzyme analysis of the DNA from a Chinese female showed that one of her chromosomes had a >17.5 kb deletion of DNA, including the , 2, and 1 globin genes, which is present in many Southeast Asians with an -thalassemia-1 chromosome. Her normal chromosome had the expected cluster of -like globin genes (5----2-1-3), but the segment of DNA between the two globin genes was elongated by some 0.5–0.7 kb. Analyses of various restriction sites suggested that this normal variant of the human globin gene complex is due to a crossover between a normal chromosome with () and a chromosome with an -thalassemia-2 (–3.7) and an -21-hybrid gene.  相似文献   

4.
Summary We have prepared the nucleoamino acids 1-(3-amino, 3-carboxypropyl)uracil (3) and 9-(3-amino, 3-carboxypropyl)adenine (4) as (l)-enantiomers and as racemic mixtures. When3 or4 is suspended in water and treated with N,N-carbonyldiimidazole, peptides are formed in good yield. The products formed from the (l)-enantiomers are hydrolyzed to the monomeric amino acids by pronase.Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (l)-enantiomer of3 did not act as templates to facilitate the oligomerization of4.  相似文献   

5.
Summary A review is given of primary and associated electron transport reactions in various division of photosynthetic bacteria and in the two photosystems of plant photosynthesis. Two types of electron acceptor chains are distinguished: type Q, found in purple bacteria, Chloroflexus and system II of oxygenic photosynthesis and type F, found in green sulfur bacteria, Heliobacterium and photosystem I. Secondary donor reactions are discussed in relation to plant photosystem II.Dedicated to the memory of Warren L. Butler  相似文献   

6.
Summary Two extracellular -glucosidases (EC 3.2.1.21) were isolated from Aspergillus niger USDB 0827 and A. niger USDB 0828, and their physical and kinetic properties studied. Both enzymes were very similar in terms of molecular size (230000 Da), pH optimum (pH 4.6), temperature optimum (65° C), stability at high temperatures and substrate preferences. They were capable of hydrolysing -linked disaccharides, phenyl -d-glucoside, p-nitrophenyl -d-glucoside (PNPG), o-nitrophenyl -d-glucoside, salicin and methyl -d-glucoside but lacked activity towards -linked disaccharides, a range of p-nitrophenyl monoglycosides and p-nitrophenyl diglycosides. Both -glucosidases were better at hydrolysing cellobiose than cellotriose, cellotetraose or cellopentaose. For both enzymes, glucose showed competitive inhibition with PNPG as substrate but had no effect with cellobiose. However, the two -glucosidases differed in inhibition by glucono-1,5-lactone and affinity for cellobiose. -Glucosidase from A. niger USDB 0827 also gave lower specific activity, and was more susceptible to metal ions (Ag+, Fe2+ and Fe3+) inhibition than that of A. niger USDB 0828. Correspondence to: Y. K. Hoh  相似文献   

7.
Newborn rat adrenocortical cells were successfully cultured in a serum free carrier protein free medium (SPFM) by using -cyclodextrin as a cholesterol carrier and have expressed corticosteroid biosynthesis in this medium. A stable inclusion complex of cholesterol--cyclodextrin with a molar ratio of almost 1 was obtained for a 5 × 10–5 mol/1 -cyclodextrin concentration. Cell cultures incubated with [4-14C] cholesterol--cyclodextrin in SPFM produced, under ACTH stimulation, various 14C labeled steroids with a predominance of corticosterone and 18-hydroxy-11-deoxycorticosterone. As measured by gas chromatography and mass spectrometry, the ratio between corticosteroids (21-hydroxylated steroids) and 20-reduced steroids produced in SPFM with cholesterol--cyclodextrin was equal to 1.8. This corresponds to a value of 3.6 times higher than that found in the serum free medium with cholesterol-albumin. Consequently, the chemically defined SPFM with cholesterol--cyclodextrin used in this study is more suitable for corticosteroidogenesis by adrenal cells in culture than a serum free medium with cholesterol-albumin.Abbreviations -CD -cyclodextrin - ACTH adrenocorticotropic hormone - 20-dihydroprogesterone 20-hydroxy-4-pregnene-3-one - 11-hydroxy-20-dihydroprogesterone 11, 20-dihydroxy-4-pregnene-3-one - 11-hydroxyprogesterone 11-hydroxy-4-pregnene-3,20-dione - C--CD cholesterol--cyclodextrin complex - corticosterone 11,21-dihydroxy-4-pregnene-3,20-dione - deoxycorticosterone 21-hydroxy-4-pregnene-3,20-dione - 18-hydroxy-11-deoxycorticosterone 18,21-dihydroxy-4-pregnene-3,20-dione - 18-hydroxy-20-dihydroprogesterone 18-20-dihydroxy-4-pregnene-3-one - 18-hydroxyprogesterone 18-hydroxy4-pregnene-3,20-dione - progesterone 4-pregnene-3,20-dione - SFM-S serum-free medium - SPFM serum-free protein-free medium - SSM serum supplemented medium  相似文献   

8.
Summary The BSG test was used in an investigation of the linear differentiation in rye variety Zhitkinskaya, common wheat variety Aurora and two secondary Triticale namely AD-196 and F-1239.Chromosomes of Aurora variety and wheat chromosomes within Triticale may be easily divided into constant and variable chromosomes as described previously (lordansky et al. 1977; Zurabishvili et al 1977).It is necessary to emphasize that the diversity of variable chromosomes underlies karyotypical polymorphism within wheat and Triticale species. The polymorphism observed exists in parallel with strict homomorphism of homologous chromosomes.In IB chromosomes of Aurora variety, the short arm is substituted by the rye chromosome arm. The karyotype of Triticale AD-196 consists of six pairs of rye chromosomes and fifteen pairs of wheat chromosomes.  相似文献   

9.
According to published reports, all strains ofMoraxella osloensis and Moraxella (Oligella) urethralis grew on a mineral-base medium supplemented with 0.015M (0.123%) sodium acetate, but not all alkalinized a mineral-base medium supplemented with 0.008% bromthymol blue and 0.2% sodium acetate. This seeming discrepancy was examined. The growth of most strains ofM. urethralis was inhibited by 0.008% bromthymol blue, and some by 0.2% anhydrous sodium acetate. All (42) strains ofM. osloensis andM. urethralis alkalinized a mineral-base medium supplemented with 0.1% sodium acetate trihydrate and 0.001% bromthymol blue or phenol red.  相似文献   

10.
Summary An enzyme with -galactosidase activity and an apparent molecular weight of 82 kDa was purified from culture medium of Aspergillus niger. The N-terminal amino acid sequence of the purified protein shows similarity to the N-terminal amino acid sequence of -galactosidases from several other organisms. Oligonucleotides, based on the N-terminal amino acid sequence, were used as probes to clone the corresponding gene from a EMBL3 gene library of A. niger. The cloned gene (aglA) was shown to be functional by demonstrating that the 82 kDa -galactosidase is absent from a strain with a disruption of the agIA gene, and is over-produced in strains containing multiple copies of the aglA gene. Enzyme activity assays revealed that the 82 kDa -galactosidase A represents a minor extracellular -galactosidase activity in A. niger.  相似文献   

11.
The genes encoding the two polypeptide chains ( and) that comprise the murine Ia antigens were localized within distinct regions of the major histocompatibility complex (MHC). This was accomplished by correlating allelic forms of the and chains with the MHC congenic strains of mice from which they were isolated. Allelic forms of and chains were distinguished by their unique structural markers, such as isoelectric points, amino acid sequences or peptide maps. The results indicate that the structural genes for both the and chains of I-A subregion antigens are located within the K to I-A genetic interval. In contrast, the gene encoding the chain of I-E subregion antigens is located outside of theI-E subregion and within the K to I-B genetic interval. These findings may have important implications for analysis of observations that complementation by twoI-region genes is sometimes required for development of immune responses.  相似文献   

12.
Summary Novel sugars, oligoglucosyl-inositols, which were synthesized using CGTase fromBacillus ohbensis, stimulated the growth ofBifidobacterium. The enzyme catalyzed transglucosylation from -1,4-maltodextrin (donor) tomyo-inositol (acceptor). Of donors examined, -cyclodextrin gave superior oligoglucosyl-inositol yield of 56.6% (w/w) based on the conversion ratio of incubated inositol. Maltosyl-inositol stimulated growth ofB. adolescentis by 194% when compared with glucose.  相似文献   

13.
Summary Analysis of -thalassemia syndromes in several German families revealed DNA deletion as well as nondeletion forms as the molecular basis for the defects. Thus, the -thalassemia haplotype was identified as the (–)3.7 rightward deletion form, and the region of the putative recombination process generating such a deletion was further characterized. In addition three different ° haplotypes, (--)MED, (--)>26, and ()T, could be detected using -and -globin gene-specific probes.  相似文献   

14.
The growth of miniature rose (Rosa chinensis Jacq. Minima) shoots cultured on liquid medium was greater relative to those cultured on two-phase (solid + liquid) medium or solid medium alone. Shoot multiplication ratio (number of multiple shoots per explant per subculture) on liquid medium was higher with 17.8–26.6 M 6-benzyladenine at compared to that at 0–8.9 M. Shoots grown on 30 ml or more of liquid medium had a higher multiplication ratio than those grown on 10 or 20 ml. The growth and multiplication ratio increased when the culture period was extended from 3 to 6 weeks, although plantlets began to exhibit some chlorosis by the 6th week. These conditions were maintained over four subcultures for cultivars Baby Katie, Lavender Jewel, Red Sunblaze and Royal Sunblaze, with no significant change in multiplication ratio over time.Abbreviations BA 6-benzyladenine - NAA 1-naphthaleneacetic acid  相似文献   

15.
Summary Highly deacetylated chitosan was accumulated in the mycelia ofMucor rouxii orPhycomyces blakesleeanus. These cultures also effected the deacetylation of the chitin ofAspergillus niger mycelium into chitosan. After 96 hours of incubation with these cultures the degree of acetylation of commercial crab shell chitosan was reduced from 25.0% to values between 4.3 and 8.6%. The potential exists for the production of chitosans with tailored physico-chemical properties from waste chitin.  相似文献   

16.
Isopropylidenation of lactose with 2,2-dimethoxypropane in the presence ofp-toluenesulfonic acid gave two products, which were identified by1H- and13C-NMR as 2,35,63,4-tri-O-isopropylidenelactose dimethyl acetal (1) and its 6-O-(2-methoxy)-isopropyl derivative (2). These products were used for the synthesis of 2-O-methyllactose (7), 2,6-di-O-methyllactose (9) and 2-O-benzyllactose (13).  相似文献   

17.
Résumé Nous avons fait élever des larves d'Anergates atratulus par des ouvrières deMyrmica laevinodis à 22°C. Pour y parvenir, il n'est pas utile de faire hivernerensemble les larves d'Anergates et les ouvrières deMyrmica. La présence de larves autochtones n'empêche pas lesMyrmica d'élever des larves d'Anergates. Dans toutes les expériences lesMyrmica ont été soumises au fridavant de recevoir des larves d'Anergates. Aucune reine deMyrmica n'a été utilisée dans ces expériences.Sur les 64 larves d'Anergates que nous avons utilisées, 38 se sont transformées en imagos. C'est au début de l'adoption et au moment des métamorphoses que périrent la plupart des 26Anergates perdus. Les femelles vécurent en général 2 ou 3 jours et cherchèrent très tôt à quitter le nid natal. Les mâles vécurent 2 à 3 semaines.
Summary Larvae ofAnergates atratulus were experimentally reared by workers ofMyrmica laevinodis, at 22°C. An overwintering of both larvae ofAnergates and workers ofMyrmica is not necessary for the success of that experiment. The presence of larvae ofMyrmica does not keep theMyrmica from rearing larvae ofAnergates. The workers ofMyrmica have been cooled, in all the experiments, before receiving larvae ofAnergates. No queen ofMyrmica have been used in that experiments.38 of the 64 larvae ofAnergates used became imagos. Most of the 26 lostAnergates died at the beginning of the adoption and during the metamorphosis. The females lived generally 2 or 3 days and tried, very early, to leave their native nest. The males lived 2 or 3 weeks.

Anergates atratulus Myrmica laevinodis, 22 . bmecme Anergates Myrmica. Myrmica Anergates. Myrmica Anergates. Myrmica . 64 Anergates , 38 . 26 Anergates 2 3 . 2 3 .
  相似文献   

18.
Photosynthetic potential of isolated chloroplasts was investigated during in situ water deficits. An eight day stress cycle imposed on spinach plants reduced leaf w by 0.57MPa, and leaf by 0.50MPa, resulting in partial turgor maintenance during the stress cycle. Pressure/volume curves confirmed the occurrence of osmotic adjustment. Leaf depression was associated with an altered response of chloroplasts to low in vitro. Optimum reaction medium for photosynthesis shifted from –1.04 to –1.57MPa, and low was not as inhibitory to photosynthesis of plastids pre-exposed to stress in situ. These data indicate that chloroplasts acclimate to low external in response to leaf water deficits. This response was still evident four days after a stress cycle ended, but was nearly reversed eight days after stress. Repeated stress cycles in situ did not increase the degree of chloroplast acclimation to low in vitro. Fast dehydration of leaves did not induce this apparent chloroplast acclimation.Abbreviations osmotic potential - w water potential - PEG polyethylene glycol 8000 - MPa megapascals  相似文献   

19.
Summary The inheritance of resistance to brown planthopper, Nilaparvata lugens (Stol.), of 20 rice cultivars was studied. Single dominant genes that are allelic to Bph 3 condition the resistance in cultivars Ptb 19, Gangala (Acc. 7733), Gangala (Acc. 15207), Horana Mawee, Kuruhondarwala, Mudu Kiriyal and Muthumanikam. Single recessive genes that are allelic to bph 4 govern the resistance in cultivars Gambada Samba, Heenhoranamawee, Hotel Samba, Kahata Samba, Kalukuruwee, Lekam Samba, Senawee, Sulai, Thirissa and Vellai Illankali. The resistance in Ptb 33, Sudu Hondarwala, and Sinna Sivappu is governed by one dominant and one recessive gene which segregate independently of each other. The dominant resistance genes in these cultivars appear allelic to either Bph 1 or Bph 3. Similarly, the recessive genes in these cultivars seem allelic to either bph 2 or bph 4. Further investigations are needed to conclusively determine the allelic relationships of resistance genes in Ptb 33, Sudu Hondarwala and Sinna Sivappu.  相似文献   

20.
The subject RNA models the binding site for the coat protein of the R17 virus, as well as the ribosome recognition sequence for the R17 replicase gene. With an RNA of this size, overlaps among the sugar protons complicate assignments of the 1H NMR spectrum. The cross peaks that overlap significantly in 2D-NOE spectra can frequently be resolved by introducing a third, in our approach the double-quantum, frequency axis. In particular the planes in a 3D-NOE/2QC spectrum perpendicular to the 2Q axis are extremely useful, showing a highly informative repeating NOE-2Q pattern. In this experiment substantial J-coupling confers special advantages. This always occurs for geminal pairs (H5/H5 for RNA plus H2/H2 for DNA), as well as for H5/H6, for H3/H4 in sugars with substantial populations of the N-pucker, for H1/H2 for S-puckered sugars, and usually for H2/H3. For the 24-mer RNA hairpin the additional information from the 3D-NOE/2QC spectrum allowed assignment of all of the non-exchangeable protons, eliminating the need for stable-isotope labeling.  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