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1.
SYNOPSIS Sporogony of oocysts of Isospora felis from the cat was studied by observing the individual oocysts. Unsporulated oocysts were passed with the fresh feces. The sporont divided into 2 ball-like sporoblasts which elongated and changed into sporocysts each of which 4 sporozoites then formed. All of the sporulating oocysts completed sporulation at 20 C in 40 hr, at 25 C in 24 hr, at 30 C in 12 hr, and at 38 C in 8 hr. The percentages of oocysts which sporulated at 20, 25, 30 and 38 C were 96, 95, 95 and 95 respectively. No sporulation occurred at 45 C and 50 C when oocysts were incubated for 4 hr. These oocysts evidently died because, on reincubation at 30 C for 4 hr, they failed to develop.  相似文献   
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Examination by swabbing a 100 cm2 area adjacent to the anus demonstrated Clostridium perfringens on 29 of 100 beef, 66 of 100 pork and 85 of 100 lamb carcasses samples before chilling at a commercial abattoir at the end of the slaughter line. Numbers were generally low (20/100 cm2). Serotypes implicated in a high percentage of food poisoning outbreaks in the UK were detected at about the same frequency as others.  相似文献   
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The epidermal structure of the five species of ferns, Arthromeriswallichiana (Spr.) Ching., Drymoglossum piloselloides (Prest.),Drynaria quercifolia (L.) J. Smith, Lepisorus nudus (Hook.)Ching. and Pyrrosia nuda (Gies.) Ching., has been investigated.Fifteen types of stomatal structures have been identified ofwhich copolo-desmocytic and coperi-desmocytic are new types.Four more possible stomatal structures: ccpolo-peri-, codesmo-polo-,codesmo-peri- and duplodesmocytic, are suggested. Localizationof starch, insoluble polysaccharides, protein and lipids hasbeen examined histochemically in the guard cells, subsidiarycells and epidermal cells. In Drynaria starch plastids and plastidscontaining both starch and protein are present in guard cells.Starch plastids are present in the subsidiary cells of all speciesexcept in Arthromeris, whereas, they are present in epidermalcells of only Drymoglossum and Lepisorus. Granular or amorphousinsoluble polysaccharides (other than starch) are present inguard cells of all the species, in the subsidiary cells of Arthromeris,Drynaria and Pyrrosia, and in the epidermal cells of Pyrrosia.Except in Pyrrosia lipids are present in the guard cells. Subsidiarycells of Drynaria and the epidermal cells of Arthromeris andDrynaria show lipid bodies. The presence of plasmodesmata andectodesmata is demonstrated in the epidermal cells of Drymoglossum.  相似文献   
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The structure and development of stomata in eight species ofCrotalaria belonging to the family Papilionaceae are described.The study is mostly confined to the leaves but it has also beenmade on the floral organs of C. mysorensis, C. retusa, C. sericea,and C. triquetra. The stomata may be paracytic, anisocytic,anomocytic, diacytic, or with one subsidiary cell. The differenttypes occur individually or they are placed side by side evenon the same surface of an organ. In general the paracytic typeis by far the commonest, followed by anisocytic and anomocyticones. Diacytic stomata and those with one subsidiary cell arerelatively rare. Different types of stomata in various organsof the same plant develop mesogenously. The present investigationalso indicates that the inconstancy of stomata in the familyis due to (a) their diversity and (b) an increase in the numberof subsidiary cells either by their division or by the neighbouringperigenes becoming subsidiary cell-like.  相似文献   
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BABU  A. M.; SHAH  J. J. 《Annals of botany》1987,59(3):293-299
Administration of ethephon (2-chloroethyl phosphonic acid) inthe stem of Bombax ceiba L. (Bombacaceae) induced the formationof a barrier zone of several layers of traumatic parenchymacells from the vascular cambium. These cells accumulate polysaccharidesand phenolics at irregular intervals, and eventually break downinitiating a gum cavity. The lysis of cells proceeds in a definiteway keeping characteristic islands of parenchyma intact in thetraumatic tissue. So the traumatic parenchyma is organized intoseveral large horizontal conical projections of uniform shapeand cell composition amidst the tangentially anastamosing cavities.The projections have a central core of radially elongated cellsand a few layers of peripheral cambiform cells. The derivativesof the cambiform cells enlarge, accumulate polysaccharides andphenolics, and disintegrate in the cavity. Later, disintegrationof some of the projections further enlarges the cavity. Bombax ceiba, ethephon, gum cavities, unusual tissue complexes  相似文献   
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The mahseers (Tor, Neolissochilus and Naziritor) are an important group of fishes endemic to Asia with the conservation status of most species evaluated as threatened. Conservation plans to revive these declining wild populations are hindered by unstable taxonomy. Molecular phylogeny studies with mitochondrial genome have been successfully used to reconstruct the phylogenetic tree and to resolve taxonomic ambiguity. In the present study, complete mitochondrial genome of Tor tor has been sequenced using ion torrent next-generation sequencing platform with coverage of more than 1000 ×. Comparative mitogenome analysis shows higher divergence value at ND1 gene than COI gene. Further, occurrence of a distinct genetic lineage of T. tor is revealed. The phylogenetic relationship among mahseer group has been defined as Neolissochilus hexagonolepis ((T. sinensis (T. putitora, T. tor), (T. khudree, T. tambroides)).  相似文献   
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Many guidelines for international research require that studies be responsive to host community health needs or health priorities. Although responsiveness possesses great intuitive and rhetorical appeal, existing conceptions are confusing and difficult to apply. Not only are there few examples of what research the responsiveness requirement permits and what it rejects, but its application can lead to contradictory results. Because of the practical difficulties in applying responsiveness and the danger that misapplying responsiveness could harm the interests of developing countries, we argue that responsiveness should be refocused in three ways: in terms of (1) who enforces it, (2) under what standard, and (3) in what cases. We conclude that responsiveness should be applied by host country officials at the policy level with the exercise of judgment when externally funded research threatens to displace scarce local resources.  相似文献   
10.
SHAH  J. J.; JACOB  RAJU 《Annals of botany》1969,33(5):855-863
Light microscopic studies of the petioles of Lagenaria sicerariareveal that the external phloem of each bicollateral vascularbundle develops earlier than the internal phloem, and that thesieve elements of the external phloem are arranged in the outerand inner zones. Each sieve element of L. siceraria and Momordicacharantia is vertically associated with a maximum of six andtwo companion cells respectively. Discrete granular bodies seenin the cytoplasm of young sieve elements develop into globular,oval, or elongated slime bodies. Enlargement and fusion of slimebodies, and the subsequent dispersal of slime occur in the parietalcytoplasm. The dispersal of slime coincides with degradationof the nucleus and perforation of the pore sites. Before nucleardisorganization, the sieve-element nucleolus is extruded. Slimeafter its immediate dispersal appears amorphous and uniformlydistributed in the sieve elements. Plugs exhibit varying degreesof condensation of slime near the sieve plates. Certain maturesieve elements in the external phloem of L. siceraria have ovalbodies which we consider reaggregated or undispersed slime.Evidence has been obtained that a central cavity occurs in afew, almost mature, sieve elements wherein the cytoplasm includingthe slime is peripheral.  相似文献   
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