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11.
Distinct effects of climate warming on populations of silver fir (Abies alba) across Europe 下载免费PDF全文
12.
The Korean species of the genus Eudorylas Aczél have been studied. A total of 16 species are arranged herein. Among them, E. paraappendiculatus sp. nov. is new to science, and E. nomurai Morakote et Yano, 1990 is newly recorded in the Korean fauna. 相似文献
13.
Summary Wounding in higher plants leads to an increased synthesis of specific messenger RNAs. A cDNA clone complementary to a wound-induced message from potato tubers was used to isolate a lambda clone from a genomic library of Salanum tuberosum var. Maris Piper. DNA sequence analysis has shown that this single genomic clone contains two novel wound-induced genes, called win1 and win2, organised in close tandem array. The coding sequences of these two genes are highly homologous and are interrupted by a single intron. However, the sequences of the introns and flanking regions have diverged widely. Win1 and win2 encode cysteine-rich proteins of 200 and 211 amino-acids, respectively, which show striking homologies to several chitin-binding proteins. Southern analysis of genomic DNA has shown that win1 and win2 are members of a small multi-gene family which is estimated to have a minimum of five members per haploid genome of Maris Piper and appears to be conserved within the Solanaceae. We have shown by Northern analysis and S1 mapping that the two genes exhibit differential organ-specific expression after the wounding of a potato plant. 相似文献
14.
Changes in gene expression during foliar senescence and fruit ripening in tomato (Lycopersicon esculentum Mill.) were examined using in-vitro translation of isolated RNA and hybridization against cDNA clones.During the period of chlorophyll loss in leaves, changes occurred in mRNA in-vitro translation products, with some being reduced in prevalence, whilst others increased. Some of the translation products which changed in abundance had similar molecular weights to those known to increase during tomato fruit ripening. By testing RNA from senescing leaves against a tomato fruit ripening-related cDNA library, seven cDNA clones were identified for mRNAs whose prevalence increased during both ripening and leaf senescence. Using dot hybridization, the pattern of expression of the mRNAs corresponding to the seven clones was examined. Maximal expression of the majority of the mRNAs coincided with the time of greatest ethylene production, in both leaves and fruit. Treatment of mature green leaves or unripe fruit with the ethylene antagonist silver thiosulphate prevented the onset of senescence or ripening, and the expression of five of the seven ripening- and senescence-related genes.The results indicate that senescence and ripening in tomato involve the expression of related genes, and that ethylene may be an important factor in controlling their expression.Abbreviations cDNA
copy-DNA
- MW
molecular weight
- PAGE
polyacrylamide gel electrophoresis
- SDS
sodium dodecyl sulphate 相似文献
15.
Plasmid-free Enterococcus faecalis excrete peptides (sex pheromones) which specifically induce a mating response in strains harboring certain conjugative plasmids. The response is characterized by the synthesis of a “fuzzy” surface material, visible by electron microscopy, which is believed to facilitate the aggregation of donors and recipients. Transconjugants which receive a specific plasmid shut down the production of endogenous pheromone; however, they continue to produce pheromones specific for donors harboring different classes of plasmids. In this review, we summarize what is known about the biochemistry and genetics of this phenomenon. Some emphasis is given to the hemolysin plasmid pAD1 and the regulation of its conjugal transfer. 相似文献
16.
Don G. Lin Naomichi Nishio Tapan Kumar Mazumder Shiro Nagai 《Applied microbiology and biotechnology》1989,30(2):196-200
Summary The selective formation of three tetrapyrroles, Co-containing corrinoids, Ni-containing factor F430 and Fe-containing cytochromes (haems) by Methanosarcina barkeri Fusaro (DSM 804) was achieved as a function of the concentrations of Co2+, Ni2+ and Fe2+ in a methanol minimmum medium. It was found that about 70% of the total tetrapyrroles synthesized was excreted into the culture supernatant. Hence, the continuous production of tetrapyrroles in a fixed-bed reactor (supporter: porous diatomaceous clay) was carried out at a dilution rate of 10 day-1 (850 ml medium/85 ml column/day). The effluent discharged from the reactor contained the excreted tetrapyrroles, the concentrations of which were dependent upon the Co2+, Ni2+ and Fe2+ concentrations in the feed medium. The maximum productivities from the reactor (1 l basis) were 52 M corrinoids/day, 24 M F430/day and 8 M haems/day, respectively. 相似文献
17.
The mechanism of secretory granule formation and exocytosis in the endocrine cells of normal and transplanted rat pancreas was studied using electron microscopy. On the one hand, formation of secretory granules starts with the dilatation of the 2 ends or the vesicularization of the middle parts of rough endoplasmatic reticulum (RER). On the other hand, prohormone ribosomes condense into the vesicles of the GOLGI apparatus. This probably indicates that the GOLGI complex is not the only source of formation of secretory granules. Exocytosis occurs with the formation of an electron dense streak between the perigranular membrane and the apical cell membrane. This is followed by the rupture of the streak at this midpoint allowing the granule to extrude into the space between the cell membrane and the parenchymal basal membrane. This fusion-rupture-extrusion mechanism repeats itself at the parenchymal and capillary basal membranes and also at the endothelium until it gets into the capillary lumen, showing that hormones of pancreatic endocrine cells may be actively transported into circulation as intact secretory granules. There is no significant morphological difference between the mechanism of secretory granule formation in normal and transplanted pancreatic tissue. 相似文献
18.
19.
Summary To extend the available information on the significance of the interactions between glycolytic enzymes and the actin component of the cellular ultrastructure, investigations into the compositional characteristics of the actin binding site on one of the major glycolytic enzymes, aldolase, have been undertaken. As the electrostatic nature of the association has been previously reported indicative of a cationic region on the enzyme involved in the binding, these studies have investigated the possibility of the involvement of histidine residues in this binding region. By the use of the histidine specific reagent, diethylpyrocarbonate, we have been able to establish a difference in nature of an actin binding domain and the active site domain which does contain an essential histidine. The results have been discussed in relation to the significance of this finding with respect to the binding of aldolase to subcellular structure. 相似文献
20.
The periplasmic location of enzymes A and B of the thiosulphate-oxidizing multienzyme system of Thiobacillus versutus has been further confirmed by differential radiolabelling of periplasmic and cytoplasmic proteins. The stoichiometries of respiration-driven proton translocation in T. versutus were determined using the oxygen pulse and the initial rate methods. A value for the H+/O quotient (number of protons translocated per oxygen atom reduced) of about 2.8 was found for the oxidation of thiosulphate, and of about 2.5 for sulphite. The H+/O quotient for endogenous respiration was about 5.7. The data are shown to be in good agreement with the scheme proposed previously for thiosulphate oxidation by this organism. Proton generation during the oxidation of thiosulphate or sulphite is indicated to occur in the periplasm rather than by pumping across the cytoplasmic membrane. The results also suggest that a H+/O quotient of six occurs during NADH oxidation (from endogenous metabolism measurements) and that the terminal cytochrome oxidase, aa3, does not function as a proton pump.Abbreviations DCCD
dicyclohexyl carbodiimide
- FCCP
carbonyl cyanide p-trifluoromethoxyphenylhydrazone
- HQNO
2-n-heptyl-4-hydroxyquinoline N-oxide
- TMPD
N,N,N,N-tetramethyl-p-phenylenediamine
- IEF
isoelectric focusing
- HIC
hydrophobic interaction chromatography
- EAI
ethyl acetimidate hydrochloride
- IAI
isethionyl acetimidate 相似文献