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Shear-oriented Microfibrils in the Mucilaginous Investments of Two Motile Oscillatoriacean Blue-Green Algae 总被引:8,自引:4,他引:4 下载免费PDF全文
Hayes C. Lamont 《Journal of bacteriology》1969,97(1):350-361
Trichomes of two oscillatoriacean blue-green algae execute screw-like gliding motion, but the two organisms differ from each other with respect to the screw sense of motion. Electron microscopy of serial longitudinal sections reveals extracellular microfibrils which lie roughly parallel to stream-lines at the surface of each organism. The author proposes that the microfibrils are oriented by shear in a zone just external to the outer unit membrane-like component of the cell wall. 相似文献
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Hayes C. Lamont 《Archives of microbiology》1969,69(3):237-259
Summary Trichomes of Microcoleus vaginatus, a motile blue-green alga of the family Oscillatoriaceae, were studied by light and electron microscopy in an effort to determine the sites of trichome breakage during production of hormogonia.According to the evidence presented herein, transcellular breakage of trichomes is the only mechanism of hormogonium production in M. vaginatus. Tearing of the murein sacculus appears to be necessary and sufficient for transcellular breakage to ensue. As Fuhs and earlier investigators have correctly claimed, this process always involves the death of the cell whose wall is torn.When trichomes of M. vaginatus break across cells to produce hormogonia, the murein sacculus usually tears along a circumferential set of junctional pores. This particular mechanism of trichome breakage is not universal among members of the family Oscillatoriaceae.This report is based on a thesis submitted in partial fulfillment of the requirements for a Ph. D. degree in Biology at Harvard University. 相似文献
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Rolf E. Flygare Stevan H. Broderson E. Russell Hayes 《Biotechnic & histochemistry》1970,45(4):149-153
A neutralized Schiff's reagent (pH 6.7) was prepared and used to investigate the role of the acidic nature of the routine Schiff's reagent (pH 2.6) in the plasmal reaction. The neutralized reagent was satisfactory as an aldehyde reagent in the nucleal reaction on gut and, although giving a less intense reaction than the routine reagent in the PAS reaction on the gut and plasmal reaction on the aorta, was satisfactory here in respect to localization and thus to aldehyde specificity. Control sections for the plasmal reaction of unfixed nerve and aorta gave positive results when placed in the routine Schiff's, this increasing with time left in the reagent. Similar control sections in the neutralized Schiff's reagent remained consistently negative even though left in this reagent for 0.5 hr. The positive reaction of such control sections is apparently due to acid hydrolysis of labile plasmalogens by the routine Schiff's reagent in myelin and elastin and not to the presence of “free” aldehydes in these tissue elements 相似文献
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Differential Tolerance of Streptomycetes to Sodium Chloride as a Taxonomic Aid 总被引:2,自引:1,他引:1 下载免费PDF全文
A survey was made of the NaCl tolerance of approximately 1,300 Streptomyces strains belonging to 313 species. The growth medium of the organisms was supplemented with a graded series of NaCl concentrations (4, 7, 10, and 13%). Only 1.8% of the species could not tolerate 4% NaCl; 26.9% could grow at a maximum of 4%; 49.7% could tolerate a maximum of 7%; 18.8% could grow at a maximum of 10%; and only 2.8% could tolerate 13% NaCl. In evaluating the relationships of NaCl tolerance to various taxonomic features, higher tolerance was statistically associated with the "yellow" and possibly the "white"-spored streptomycetes, whereas the "red"-spored series tended to have lesser tolerance. Higher tolerance was also indicated for spiny-spored species, as a group, than for smooth-spored forms. Likewise, nonproducers of melanin, collectively, were more NaCl tolerant than melanin-producing species. Uniformity of test responses between strains of species studied suggested the usefulness of NaCl tolerance as a taxonomic criterion. 相似文献
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Incidence of Clostridium botulinum Type E in Salmon and Other Marine Fish in the Pacific Northwest 总被引:4,自引:3,他引:1 下载免费PDF全文
Salmon, sole, cod, oysters, clams, and crabs from ocean waters along the coast of Oregon and Washington were examined for the presence of Clostridium botulinum type E. The organism was detected by identification of the type E toxin in enrichment cultures of the viscera of individual fish. Of 369 salmon specimens, 48 yielded cultures containing toxin lethal to mice, and almost half of the toxic cultures were shown to contain botulinal toxin, chiefly type E. Eighteen of 113 sole and cod specimens, 4 of 22 Dungeness crab specimens, 5 of 16 oyster specimens, and 27 of 115 clam specimens gave rise to cultures containing botulinal toxin which was usually type E, although types A and B were occasionally encountered. 相似文献
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