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The genus Typhlodromus in Sudan includes five species. Of these, three new species are described and illustrated in this work. Individuals of T. sudanicus Elbadry and T. medanicus Elbadry have been found to play an important role in feeding on phytophagous mites and white fly nymphs infesting cotton crop.
Typhlodromus niloticus sp. n. and T. balanites sp. n. from fruit trees feed on tetranychid and eriophyid mites. T. sennarensis sp. n. has been collected from wild plants.
A key is provided for the identification of members of the genus Typhlodromus in Sudan. 相似文献
Typhlodromus niloticus sp. n. and T. balanites sp. n. from fruit trees feed on tetranychid and eriophyid mites. T. sennarensis sp. n. has been collected from wild plants.
A key is provided for the identification of members of the genus Typhlodromus in Sudan. 相似文献
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T J McMahon J S Hood B D Nossaman I N Ibrahim C J Feng P J Kadowitz 《Journal of applied physiology》1991,71(5):2012-2018
The effects of SQ 30741, a thromboxane A2 (TxA2) receptor blocking agent, on responses to the TxA2 mimic, U-46619, were investigated in the pulmonary vascular bed of the intact-chest cat under constant-flow conditions. The administration of SQ 30741 in doses of 1-2 mg/kg iv markedly reduced vasoconstrictor responses to U-46619 without altering responses to prostaglandin (PG) F2 alpha or PGD2 and serotonin. SQ 30741 had no significant effect on mean vascular pressures in the cat, and the dose-response curve for U-46619 was shifted to the right in a parallel manner with a similar apparent maximal response. In addition to not altering responses to PGF2 alpha, PGD2 alpha, or serotonin, SQ 30741 (2 mg/kg iv) was without significant effect on pulmonary vasoconstrictor responses to the PGD2 metabolite 9 alpha, 11 beta-PGF2, norepinephrine, angiotensin II, BAY K 8644, endothelin 1, or endothelin 2. Although responses to vasoconstrictor agents, which act through a variety of mechanisms, were not altered, responses to the PG and TxA2 precursor, arachidonic acid, were reduced significantly. The duration of the TxA2 receptor blockade was approximately 30 and 75 min at the 1- and 2-mg/kg iv doses of the antagonist, respectively. The present data show that SQ 30741 selectively blocks TxA2 receptor-mediated responses in a competitive and reversible manner in the pulmonary vascular bed. These data suggest that responses to arachidonic acid are due in large part to the formation of TxA2 and that discrete TxA2 receptors unrelated to receptors activated by PGD2 or PGF2 alpha are most likely located in resistance vessel elements in the feline pulmonary vascular bed. 相似文献
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Jacqueline Jollès Ellen M. Prager Emad S. Alnemri Pierre Jollès Ibrahim M. Ibrahimi Allan C. Wilson 《Journal of molecular evolution》1990,30(4):370-382
Summary Complete amino acid sequences are presented for lysozymesc from camel and goat stomachs and compared to sequences of other lysozymesc. Tree analysis suggests that the rate of amino acid replacement went up as soon as lysozyme was recruited for the stomach function in early ruminants. The two lysozymes from goat stomach are the products of a gene duplication that probably took place before the divergence of cow, goat, and deer about 25 million years ago. Partial sequences of three lysozymes from goat tears indicated that (a) the goat tear family of lysozymes may have diverged from the stomach lysozyme family by an ancient duplication and (b) later duplications are probably responsible for the multiple forms of tear and milk lysozymes in ruminants. 相似文献
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Microvillar channels: a unique plasma membrane compartment for concentrating lipoproteins on the surface of rat adrenal cortical cells 总被引:3,自引:0,他引:3
Electron microscopic studies of perfused rat adrenals indicate that plasma lipoproteins become concentrated in a specialized cell surface compartment called microvillar channels. Closely associated plasma membranes of sinusoidal microvilli of zona fasciculata cells form channels that normally are filled with electron dense particles the size of high density lipoproteins (HDL). In rats made acutely deficient in plasma lipoproteins (by treatment with 4-aminopyrazolo[3,4-d]pyrimidine (4-APP) for 1 day), particles within the microvillar channels are decreased in number. When adrenal glands of these rats are perfused with media lacking plasma lipoproteins, many but not all of these HDL-like particles are washed out. However, when these adrenals are perfused with large amounts (100-500 micrograms protein/ml) of HDL, microvillar channels become packed with electron dense particles similar to those found in vivo. These microvillar channels become wider and filled with larger particles when low density lipoproteins (LDL) are perfused through the adrenals. Autoradiograms of 125I-labeled HDL-perfused adrenals show silver grains specifically associated with the cell surface microvillar channels, and confirm the notion that the particles filling the channels are exogenously delivered HDL. Physiologic data from similarly perfused adrenals in a parallel study show that the channel-refilling process is directly related to selective (i.e., nonendocytic) cholesterol uptake and that this cholesterol uptake is associated with corticosterone production. Together, these data suggest the hypothesis that plasma lipoprotein cholesterol utilized for corticosteroid synthesis in rat adrenal fasciculata cells may be derived from lipoproteins trapped in surface-associated microvillar channels. Although the mechanism responsible for the cholesterol transfer is not yet defined, it is clearly distinct from the classical process of receptor-mediated endocytosis and catabolism of lipoprotein particles. 相似文献
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The formation of mor humus in an experimental grassland plot, which has been acidified by long-term fertiliser treatment,
has been studied by comparing the rates of cellulose, soil organic matter and plant litter decay with those in an adjacent
plot with near-neutral pH and mull humus. The decomposition of cellulose filter paper in litter bags of 5 mm, 1-mm and 45-μm
mesh size buried at 3 to 4 cm depth the plots was followed by measuring the weight loss and changes in glucose content over
a 6 month period. Soil pH was either 5.3 or 4.3. Decomposition of native soil organic matter and plant litter in soil from
the same plots were followed using CO2 evolution in laboratory microcosms. Cellulose weight loss at pH 5.3 was greatest from the 5-mm mesh bags and least from the
45-um mesh bags. At pH 4.3 there was little weight loss from bags and no significant differences in weight loss between bags
with different sized mesh. There was, however, a reduction in the glucose content of the hydrolysed and derivatised filter
paper with time. The decomposition rate of native soil organic matter in the low pH soil was increased to that observed in
the less acid soil when the pH of the former was increased from 4.3 to 5.3. The increase in decomposition rate of added plant
litter in the more acid soil as a result of CA(OH)2 addition was only 60% of that observed in the soil with pH 5.3. These data support the hypothesis that the absence of soil
animals and the restricted microbial decomposition in the acidic soil was responsible for mor humus formation. 相似文献
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We have previously identified novel members of the pentraxin family (neuronal pentraxin 1 and 2) that are expressed in the nervous system. Neuronal pentraxin 1 (NP1) was identified as a rat protein that may mediate the uptake of synaptic material and the presynaptic snake venom toxin, taipoxin. NP2 was identified as a separate gene discovered by screening for a human homolog for NP1. Here, we report human cDNA and mouse genomic DNA sequences for NP1 (gene symbol NPTX1). Human NP1 and mouse NP1 show 95 and 99% amino acid identity, respectively, with rat NP1 and conserve all potential glycosylation sites. Like rat NP1, human NP1 message is large (6.5 kb) and is exclusively localized to the nervous system. The mouse NP1 gene is 13 kb in length and contains four introns that break the coding sequence of NP1 in the same positions as the introns of the human NP2 gene. The human and mouse NP1 genes are localized to chromosome 17q25.1–q25.2 and chromosome 11e2–e1.3, respectively. These data demonstrate the existence of a separate family of pentraxin proteins that are expressed in the human brain and other tissues and that may play important roles in the uptake of extracellular material. 相似文献
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