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Histochemical localization of acetylcholinesterase and butyrylcholinesterase in the salivary glands has unfolded the significant fact that salivary glands are of two types, one being enzymatically negative and the other showing positive activity. Activity of these enzymes has been linked with the operation of glandular dynamics, particularly concerning the synthetic and secretory processes. The enzymes have been seen localized in the core of jaw. Contrary to it they are absent in the papillary and interpapillary zones of the jaw. Absence of esterases in the papillary and interpapillary ductules has been correlated with its possible non-involvement in the synthesis of vasodilating and anticoagulating materials. The experiments on effect of biting on host tissue give a faint indication of vascular dilation due to bite. Likewise, experiments on enzymatic state of a salivary gland after leech-bite reveal that the diminution of the reactive coverage area in the salivary glands reaches its maximum in the case of ATPase, indicating thereby its more involvement in salivary functions than those of esterases and acid phosphatase. 相似文献
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Although Ficus (Moraceae) is a keystone plant genus in the tropics, providing resources to many frugivorous vertebrates, its population genetic structure, which is an important determinant of its long‐term survival, has rarely been investigated. We examined the population genetic structure of two dioecious fig species (Ficus hispida and Ficus exasperata) in the Indian Western Ghats using co‐dominant nuclear microsatellite markers. We found high levels of microsatellite genetic diversity in both species. The regression slopes between genetic relationship coefficients (fij) and spatial distances were significantly negative in both species indicating that, on average, individuals in close spatial proximity were more likely to be related than individuals further apart. Mean parent–offspring distance (σ) calculated using these slopes was about 200 m in both species. This should be contrasted with the very long pollen dispersal distances documented for monoecious Ficus species. Nevertheless, overall population genetic diversity remained large suggesting immigrant gene flow. Further studies will be required to analyze broader scale patterns. 相似文献
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Sources of one-carbon units in the folate pathway of Escherichia coli 总被引:10,自引:0,他引:10
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Summary In this paperTetracoccosporium andDictyoarthrinium are treated.T. cupulatum, D. lilliputeum andD. microsporum are described new, apart from the typeD. sacchari. A key to the known species ofDictyoarthrinium is proposed.Tetracoccosporium, is a maiden report for India. 相似文献
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The present contribution incorporates an account of the distribution of adenosine triphosphatase and its functional role in various regions of the alimentary canal of Pheretima posthuma and Barogaster annandalei. The main areas, showing adenosine triphosphatase activity in P. posthuma are sub-epithelial blood vessels in pharynx, peri-oesophageal blood vessels in oesophagus, columnar epithelial cells of gizzard and in the areas outside the typhlosole and around the supra-intestinal excretory ducts. In B. annandalei the epithelial cells of gizzard show significant enzymatic localization. In addition to this, enzymatic activity has also been found in the deeply embedded blood vessels of buccal region, peri-oesophageal vasculature, sub-epithelial vasculature of typhlosole and intestine, and in the adjoining chloragogen cells. Physiological significance of the enzymatic pattern has been discussed. 相似文献