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91.
Sandra J. Walde Cebisile N. Magagula Madeleine Leigh Morton 《Experimental & applied acarology》1995,19(6):307-317
The importance of the acarine predator, Zetzellia mali, in the control of phytophagous mites in apple orchards is not well understood. Zetzellia mali tends to prefer the eriophyid, Aculus schlechtendali, over the economically more significant tetranychid, Panonychus ulmi, but quite a wide range of preference values have been reported in the literature. In sets of laboratory choice trials, we determined that prey preference of this predator varies with the relative but not absolute density of its prey. We attempt to explain these results in terms of behavioural mechanisms and discuss the potential implications of our results for the effectiveness of Z. mali in the biological control of phytophagous mites in apple orchards. 相似文献
92.
Cyanuric acid in high concentrations (15.5 mm) was degraded completely by Pseudomonas sp. NRRL B-12228 independently of glucose concentration. In the batch fermentations there was a relation between the glucose concentration, on the one hand, and the liberation of ammonia or production of protein, on the other. The greater the supply of carbon, the more biomass was produced, and fewer NH
inf4
sup+
ions were released. Continuous fermentations using adsorbed cells could be performed to degrade cyanuric acid. In spite of different glucose feeding there was only a negligible difference in residues of s-triazine. In a one-step continuous system with dilution rates between 0.021 h–1 and 0.035 h–1, even a ratio of 0.65 between glucose and cyanuric acid was not sufficient to degrade the cyanuric acid supplied (320–540 mol l–1 h–1) completely. When a continuous two-step system was applied with dilution rates between 0.035 h–1 and 0.056 h–1, the consumption of carbon source could be minimized while s-triazine degradation up to 860 mol l–1 h–1 was complete. In this way the ratio between glucose and cyanuric acid could be increased to 0.25 (molar C:N ratio = 0.33:1). Thereby the process was made considerably more economic. 相似文献
93.
Johannes Becker-Follmann Andreas Gaa Elke Baùsch Ernst Natt Gerd Scherer Otto von Deimling 《Mammalian genome》1997,8(3):172-177
We have performed a high-resolution linkage analysis for the conserved segment on distal mouse Chromosome (Chr) 8 that is
homologous to human Chr 16q. The interspecific backcross used involved M. m. molossinus and an M. m. domesticus line congenic for an M. spretus segment from Chr 8 flanked by phenotypic markers Os (oligosyndactyly) and e, a coat colormarker. From a total of 682 N2 progeny, the 191 animals revealing a recombination event between these phenotypic markers were typed for 23 internal loci.
The following locus order with distances in cM was obtained: (centromere)–Os–4.1–Mmp2–0.2–Ces1,Es1, Es22–1.2–Mt1,D8Mit15–2.2–Got2, D8Mit11–3.7–Es30–0.3–Es2, Es7–0.9–Ctra1,Lcat–0.3–Cdh1, Cadp, Nmor1, D8Mit12–0.2–Mov34–2.5–Hp,Tat–0.2–Zfp4–1.6–Zfp1,Ctrb–10.9–e. In a separate interspecific cross involving 62 meioses, Dpep1 was mapped together with Aprt and Cdh3 at 12.9 cM distal to Hp, Tat, to the vicinity of e. Our data give locus order for markers not previously resolved, add Mmp2 and Dpep1 as new markers on mouse Chr 8, and indicate that Ctra1 is the mouse homolog for human CTRL. Comparison of the order of 17 mouse loci with that of their human homologs reveals that
locus order is well conserved and that the conserved segment in the human apparently spans the whole long arm of Chr 16.
Received: 30 July 1996 / Accepted: 15 November 1996 相似文献
94.
A. H. N. Hopman Sandra Claessen Ernst J. M. Speel 《Histochemistry and cell biology》1997,108(4-5):291-298
We describe the brightfield microscopical detection of multiple DNA target sequences in cell and tissue preparations. For
this purpose, chromosome-specific DNA probes labelled with biotin, digoxigenin or fluorescein were simultaneously hybridised
and detected by enzyme cytochemistry using two horseradish peroxidase (PO) reactions and one alkaline phosphatase (APase)
reaction. For triple-colour detection on single cell preparations, the combination of the enzyme precipitates PO/diaminobenzidine
(DAB, brown colour), APase/fast red (FR, red colour) and PO/tetramethylbenzidine (TMB, green colour) resulted in an accurate
detection of DNA targets. Embedding of the preparations in a thin cross-linked protein layer further stabilised the enzyme
reaction products. For in situ hybridisation on tissue sections, however, this detection procedure showed some limitations
with respect to both the stability of the APase/FR and PO/TMB precipitates, and the sequence of immunochemical layers in multiple-target
procedures. For this reason, the APase/FR reaction was replaced by the APase/new fuchsin (NF, red colour) reaction and the
washing steps after the PO/TMB reaction were restricted to the use of phosphate buffer pH 6.0. Furthermore, to improve the
efficiency of the ISH reaction, APase/NF was applied in an avidin-biotin complex detection system and, to avoid target shielding
in the triple-target ISH, the third primary antibody was applied prior to the second enzyme cytochemical reaction. These adaptations
resulted in stable, well contrasting brown, red and green coloured precipitates. After quick haematoxylin counterstaining,
the tissue preparations were directly mounted in phosphate buffer and, optionally, embedded in the cross-linked protein layer.
Accepted: 27 June 1997 相似文献
95.
Akira F. Peters Madeleine J. H. van Oppen Christian Wiencke Wytze T. Stam Jeanine L. Olsen 《Journal of phycology》1997,33(2):294-309
Phylogenetic relationships in the Desmarestiales (Phaeophyceae) were inferred among the monotypic Arthrocladia (Arthrocladiaceae) and 27 isolates from Desmarestiaceae, representing 17 taxa of Desmarestia and the monotypic Antarctic genera Himantothallus and Phaeurus. Phaeurus and Arthrocladia were used as outgroups. Parsimony analyses of nuclear ribosomal DNA internal transcribed spacer (ITS1 and ITS2) sequences, in which gaps were both included and excluded, yielded well-resolved trees with a consistent general branching pattern. A parallel analysis of nine morphological and life-history characters and three ecological characters yielded a similar tree but provided little resolution in the terminal clades. The position of the monotypic Arthrocladia villosa within the Desmarestiales is consistent with monophyly for the order, but its position as the most primitive desmarestialean is not resolvable from the molecular data set. The basal position of Phaeurus, the Antarctic Desmarestia species, and Himantothallus is consistent with the hypothesis of a Southern Hemisphere origin for the family Desmarestiaceae. The more recent Northern Hemisphere “aculeata” clade evolved from an Antarctic ancestor. A “D. aculeata-like” species was ancestral to a lineage characterized by annual sporophytes with high sulfuric acid content, which radiated into many species, widely distributed in both hemispheres. Mapping of morphological and ecological characters onto the molecular tree confirm the informativeness of sulfuric acid-containing vacuoles and unilocular sporangial types. There is good congruence between phylogenetic tree topology and temperature impints in relation to biogeographic distribution, supporting the theory that temperature tolerance is a conservative trait. 相似文献
96.
Molecular mechanisms of endotoxin activity 总被引:20,自引:0,他引:20
Jens Schletter Holger Heine Artur J. Ulmer Ernst T. Rietschel 《Archives of microbiology》1995,164(6):383-389
Endotoxin (lipopolysaccharide, LPS), a constitutent of the outer membrane of the cell wall of gramnegative bacteria, exerts
a wide variety of biological effects in humans. This review focuses on the molecular mechanisms underlying these activities
and discusses structure-function relationships of the endotoxin molecule, its interaction with humoral and cellular receptors
involved in cell activation, and transmembrane and intra-cellular signal transduction pathways. 相似文献
97.
Wolfgang Schepp Siegfried Ernst Miederer Hans-Jörg Ruoff 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1984,804(2):192-199
Human gastric mucosal cells were isolated from the resected fundic mucosa of peptic ulcer patients. The intracellular content and secretion of intrinsic factor were estimated by binding to cyano[57Co]cobalamin. The content was maximal in the enriched parietal cell fraction which also displayed the highest H+ production as measured by amino[14C]pyrine uptake. Secretagogues evoked full response after 15 min of incubation: pentagastrin (181% of basal secretion), carbachol (208%), histamine (250%) and dibutyryl cyclic adenosine monophosphate (304%). The phosphodiesterase inhibitor isobutylmethylxanthine was slightly more effective even than dibutyryl cAMP. The response to histamine was abolished by ranitidine, indicating activation of adenylate cyclase via histamine H2 receptors, but remained unaffected by atropine, which in turn blocked the carbachol effect, whereas ranitidine was ineffective. The mean formation rate was 8.4 fmol intrinsic factor/106 cells per h under basal conditions and 14.3 fmol in response to histamine. 相似文献
98.
Growth and copper-binding of a copper-tolerant and a copper-sensitive population of Silene cucubalus (L.) Wib. have been studied. The copper-tolerant plants showed a much lower uptake and a proportionally higher transport of copper from root to shoot. A copper-binding protein with an apparent Mr of 8500 resembling metallothionein has been isolated from the roots of copper-treated plants of the tolerant population. After 20 d, the protein was observed to be inducible upon copper supply in the copper-tolerant plants, but not yet in the sensitive ones. This could be an indication of a difference in metalregulated synthesis of the protein. Ion-exchange chromatography of the 8500 protein yielded a major copper-containing fraction eluting at high ionic strength. Other characteristics such as UV absorption and amino-acid composition resembled strongly those of metallothioneins. The involvement of metallothioneins in the detoxification of copper within Cu-tolerant plants is discussed in relation to other mechanisms.Abbreviation DEAE
diethyloaminoethyl 相似文献
99.
Evidence for lysosomal enzyme recognition by human fibroblasts via a phosphorylated carbohydrate moiety 总被引:8,自引:8,他引:0
Kurt Ullrich Günther Mersmann Ernst Weber Kurt Von Figura 《The Biochemical journal》1978,170(3):643-650
Adsorptive endocytosis of five different lysosomal enzymes from various human and non-human sources was susceptible to inhibition by mannose and l-fucose, methyl α-d-mannoside, α-anomeric p-nitrophenyl glycosides of mannose and l-fucose, mannose 6-phosphate and fructose 1-phosphate. A few exceptions from this general scheme were observed for particular enzymes, particularly for β-glucuronidase from human urine. The inhibition of α-N-acetylglucosaminidase endocytosis by mannose, p-nitrophenyl α-d-mannoside and mannose 6-phosphate was shown to be competitive. The loss of endocytosis after alkaline phosphatase treatment of lysosomal enzymes supports the hypothesis that the phosphorylated sugars compete with a phosphorylated carbohydrate on the enzymes for binding to the cell-surface receptors [Kaplan, Achord & Sly (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 2026–2030]. Endocytosis of `low-uptake' forms of α-N-acetylglucosaminidase and α-mannosidase was likewise susceptible to inhibition by sugar phosphates and by alkaline phosphatase treatment, suggesting that `low-uptake' forms are either contaminated with `high-uptake' forms or are internalized via the same route as `high-uptake' forms. The existence of an alternative route for adsorptive endocytosis of lysosomal enzymes is indicated by the unaffected adsorptive endocytosis of rat liver β-glucuronidase in the presence of phosphorylated sugars and after treatment with alkaline phosphatase. 相似文献
100.
Effects of parental regurgitation feeding activity on crop sac development were studied in mate-separated male and female ring doves given 2 hr of daily exposure to food-deprived or recently fed squabs, for 4 consecutive days during the early posthatching period of the breeding cycle. In both sexes, food-deprived squabs stimulated more squab-directed activity, more parental regurgitation feeding activity, and greater crop sac development than recently fed young. Crop sac weights of males in both groups tended to be positively correlated with one or more parental activities. Correlations obtained in males exposed to food-deprived young further suggested that tactile stimuli associated with regurgitation behavior may promote crop sac development. In contrast to males, crop sac weights of females in both groups were not highly correlated with any type of contact-related parental activity or group of activities. These results, together with previous findings, suggest that nontactile stimuli from young played some role in mediating female crop sac weight differences in the two exposure conditions. 相似文献