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51.
Synthesis of Substance P 总被引:3,自引:0,他引:3
GEOFFREY W. TREGEAR HUGH D. NIALL JOHN T. POTTSJUN. SUSAN E. LEEMAN MICHAEL M. CHANG 《Nature: New biology》1971,232(29):87-89
SUBSTANCE P has been synthesized by the solid-phase procedure of Merrifield1,2 according to the sequence H-Arg-Pro-LysPro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2 reported in the previous letter. 相似文献
52.
SEVERAL mouse alloantigens described recently are expressed solely or chiefly on lymphoid cells. This indicates that the programme of selective gene action responsible for cyto-differentiation includes instructions for the synthesis of unique cell surface conformations characteristic of particular cell types1, 2. 相似文献
53.
EXCESS fat deposition after castration is thought to be a response to hyperinsulinism induced by an increased level of adrenal glucocorticoids1. Two mutant alleles, lethal yellow (Ay) and viable yellow (Avy), at the agouti locus in the mouse induce excess fat deposition; the Ay allele has also been found to induce insulin resistance2. Katsh3 concluded that in adrenalectomized KL strain mice a considerable portion of the high insulin tolerance depended on normal adrenal function. In the inbred YS/Wf and VY/Wf strains, both yellow pheno-types modulate serum insulin concentration4. Castration of inbred YS strain males causes a large decrease in serum insulin4, suggesting a possible relationship1 to the concentration of adrenal glucocorticoids. Growth of allogeneic tumour cells has different effects on the serum insulin concentrations of YS and VY strain mice4. 相似文献
54.
At least ten major mineral licks occur along the Gaji River which bisects the Yankari Game Reserve. The licks show varying degrees of utilization and have craters of up to 1200m3 in volume. Three hundred and eighty five hours of observation were kept at one of the licks. Its use by different species was highly variable. Some species occurring in the reserve made no visits to the lick, whereas Western hartebeest (51 groups), waterbuck (53 groups) and warthog (276 groups) made frequent visits. Lick use was much greater in the daytime than at night, with the peak occurring around 1400 h. A limited number of soil samples (29) were analysed but no single element can be considered as the factor attracting wildlife. However, the lick areas were richer in most minerals than were samples of soil from drier habitat in the open woodland. It is possible that significantly increased lick use might in the future indicate degrading environmental conditions in the drier parts of the reserve. If hides are constructed, the commonly utilized licks will provide excellent opportunities for behaviour observatioii and photography by tourists. 相似文献
55.
PRECIPITATION of collagen from solution in the presence of chondroitin sulphates (or certain other glycosaminoglycans), followed by dialysis against water, leads to the formation of the fibrous long spacing (FLS) polymorphic form of collagen. Electron microscopy shows this to consist of banded fibrils with a periodicity in the range 1200–2400 Å and a symmetric intraperiod structure, in contrast to the 600–700 Å periodicity and polarized fine structure characteristic of native collagen fibrils. FLS was originally reported by Highberger et al.1–3 and has been observed in three principal modifications, FLS I, FLS II and FLS III, differing in periodicity and arrangement of dense bands4–6. This letter reports a new form of FLS, denoted FLS IV. 相似文献
56.
Admissible clustering procedures 总被引:3,自引:0,他引:3
57.
SYNOPSIS. Eimeria acervulina, E. necatrix , and E. meleagrimitis sporozoites were examined for carbohydrates by cytochemical methods during dormancy, after excystation, and after penetration of cells. The only carbohydrate found was amylopectin, a homogeneous polymer of glucose. It was distributed in 3 regions: (a) in front of the anterior refractile globule, (b) around the nucleus, and (c) behind the posterior refractile globule. The relative amounts decreased after excystation and penetration of cells until only small amounts remained around the nucleus. The quantity of amylopectin decreased following excystation from 30.0-36.7 to 9.4-13.3 μg glucose/106 oocysts. Over a 6 yr period of storage at 4 C, there was a decrease in the quantity of amylopectin in dormant sporozoites of E. acervulina from 33.3 μg glucose/106 oocysts at 3 mos to 1.5 μg at 6 years. Coincidentally, 3 month- and 1 year-old oocysts of E. acervulina produced patent infections in chicks with a dosage of 5 × 104 oocysts, but only a few of the oocysts that had been stored for 2 years were infective; a dosage of 2 × 106 oocysts was necessary to produce a patent infection. Oocysts which had been stored 6 years did not produce a patent infection.
It was concluded that amylopectin is the energy source for excystation and subsequent penetration of cells. Small amounts of amylopectin are used during dormancy and, when the content in the sporozoite falls below a certain level, the sporozoites lack sufficient energy to infect cells. 相似文献
It was concluded that amylopectin is the energy source for excystation and subsequent penetration of cells. Small amounts of amylopectin are used during dormancy and, when the content in the sporozoite falls below a certain level, the sporozoites lack sufficient energy to infect cells. 相似文献
58.
SYNOPSIS. In studies on coccidial excystation, Eimeria tenella sporulated oocysts were fed to 5 individually caged chickens, and during the next 4.5 hours, all droppings were collected immediately after excretion, mixed with 0.85% NaCl solution, then promptly examined for the parasites. Some samples were placed in cold storage at 4 C and examined at intervals thereafter. Three of the birds were necropsied after 5 hours and the intestinal contents examined. Apparently unbroken oocysts containing active sporozoites were in chicken droppings beginning 1–2.25 hours postinoculation; some activated forms were inside and others outside the sporocysts. Free sporozoites, sometimes numerous, first appeared in the feces 1.1–2 hours postinoculation. At necropsy, the state and condition of the parasites in the lumen of bird intestines were similar to those in its last fecal dropping. After being in cold storage for 48 hours, free sporozoites inside and outside the oocysts became active and moved about when placed on the warming stage of the microscope. 相似文献
59.
JOHN J. CORBETT 《The Journal of eukaryotic microbiology》1970,17(2):181-182
SYNOPSIS. The classical Tetrahymena pyriformis and T. vorax strains have been classified in antigenic subgroups based on immobilization and agar double diffusion in the presence of specific antisera. The present study utilized disc electrophoresis of proteins and lactate dehydrogenase isozymes for comparison of 11 strains. In agreement with similarities reported for agar diffusion data, close electrophoretic relationships were observed between strains GL and H, and V2 and W with aniline black staining. Altho LDH isozyme production was more variable and related to cultural growth phase, similarities were recognized between GL and H, and F and PR. 相似文献
60.
JOHN R. G. TURNER 《Zoological Journal of the Linnean Society》1967,46(310):255-266
In the course of a survey of the history of the study of Heliconiinae, particularly their biology, in the eighteenth and nineteenth centuries it is shown that Heliconius nigromarginatus (Goeze) and H. pallescens (Goeze) are nomina oblita , and that H. cinereofuscus (Goeze) is not, as always supposed, a species in its own right. A new name is proposed for H. melpomene cybele (Cramer). The origin and application of some of Linnaeus' names is discussed.
Illustrations of Heliconius by Seba, Clerck, Petiver and Cramer show that three species, melpomene, erato and doris have been polymorphic at least since the middle of the eighteenth century.
The Indo-Australian genus Cethosia should probably be included in the Heliconiinae. 相似文献
Illustrations of Heliconius by Seba, Clerck, Petiver and Cramer show that three species, melpomene, erato and doris have been polymorphic at least since the middle of the eighteenth century.
The Indo-Australian genus Cethosia should probably be included in the Heliconiinae. 相似文献