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I. S. Chohan I. Singh K. Balakrishnan G. P. Talwar 《International journal of biometeorology》1975,19(3):137-143
Levels of immunoglobulins were determined in persons exposed to high altitude. The individuals studied included high altitude natives, sea level residents at high altitude for 2 years, and recent arrivals at high altitude. Increased IgG and IgA levels were found in high altitude natives and sea level residents at high altitude for 2 years when compared with sea level residents. In recent arrivals marked increase of IgG and IgG levels and slight rise in IgM was seen. Recent arrivals who suffered from high altitude pulmonary oedema showed marked elevation of IgG, IgM, and IgA. Immunoglobulin responses to both primary and secondary TAB inoculation were of a higher magnitude and more sustained at high altitude than at sea level. 相似文献
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5S-rRNA genes in rice embryos 总被引:3,自引:0,他引:3
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The presence of rRNA genes on homoeologous chromosomes 1A, 1B, and 1D of hexaploid wheat was investigated by rRNA/DNA hybridization, using DNA purified from aneuploid and substitution line derivatives of the variety Chinese Spring. Doubling the number of 1B chromosomes increased the number of rRNA genes by 31–49% but deleting the 1B chromosomes decreased the number by only 15–23%. This suggests that changes may occur in rRNA gene multiplicity at other nucleolar organizer sites to partially compensate for a deficiency of rRNA genes. There was no unequivocal evidence of rRNA genes on Chinese Spring chromosome 1A or 1D, but other varieties were shown to have rRNA genes on chromosome 1A. These results are consistent with the cytological observations that chromosomes 1A and 1B but not 1D possess nucleolar organizers. 相似文献
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The presence of actively synthetized immunoglobulin in the serum of newborn precolostral germfree piglets was confirmed. This immunoglobulin, being of IgG antigenic type, carries determinants of typical IgG heavy and light chains and has a sedimentation constant of 4S. The first antibodies formed in germfree piglets after immunization with sheep red blood cells are of macroglobulinemic (IgM) nature. They are followed by formation of more slowly sedimenting antibodies of the IgG type. No fast sedimenting antibodies of the IgG type were detected. 相似文献
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The genes for ribosomal RNA in diploid and polytene chromosomes of Drosophila melanogaster 总被引:7,自引:0,他引:7
Dr. Brian B. Spear 《Chromosoma》1974,48(2):159-179
The proportion of the Drosophila genome coding for ribosomal RNA was examined in DNA from both diploid and polytene tissues of Drosophila melanogaster by rRNA-DNA hybridization. Measurements were made on larvae with one, two, three and four nucleolus organizer regions per genome. In DNA from diploid tissues the percent rDNA (coding for 28S and 18S ribosomal DNA) was found to be in proportion to the number of nucleolus organizers present. The number of rRNA genes within a nucleolus organizer therefore does not vary in response to changes in the number of nucleolus organizers. On the other hand, in DNA from cells with polytene chromosomes the percent rDNA remained at a level of about 0.1% (two to six times lower than the diploid values), regardless of either the number of nucleolus organizers per genome or whether the nucleolus organizers were carried by the X or Y chromosomes. This independence of polytene rDNA content from the number of nucleolus organizers is presumably due to the autonomous polytenization of this region of the chromosome. When the rDNA content of DNA from whole flies is examined, both the rDNA additivity of the diploid cells and the rDNA independence of polytene cells will affect the results. This is a possible explanation for the relative rDNA increase known to occur in X0 flies, but probably not for the phenomenon of rDNA magnification. — In further studies on DNA from larval diploid tissues, the following findings were made: 1) the Ybb-chromosome carries no rDNA; 2) flies carrying four nucleolus organizers do not tend to lose rDNA, even after eleven generations, and 3) the nucleolus organizer on the wild type Y chromosome may have significantly less rDNA than does that on the corresponding X chromosome. 相似文献
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K. Rohde 《Hydrobiologia》1988,160(3):271-283
The faunas of gill Monogenea of marine teleost fishes in deep and surface waters of southeastern Australia are compared, based on extensive surveys: 1563 fish (66 or 67 species, 35 families, 15 orders) in deepwater; 1862 fish (46 species, 26 families, 7 orders) in surface water. Relative species diversity (number of species of Monogenea/all fish species examined) is approximately five times greater in surface waters. There is a similarly low relative species diversity of Monogenea in the northwestern Pacific and northwestern Atlantic deepwater. Deepwater Monogenea in all seas belong mainly to the Diclidophoroidea (13 of 19 species in southeastern Australia, 14 of 17 species in the northwestern Pacific, at least 9 of 12 (?) species in the northwestern Atlantic) predominantly Diclidophoridae. Important groups of surface Monogenea in southeastern Australia are the Microcotylidae (34 of 83 species), Dactylogyridae Ancyrocephalinae (15 species) and Capsaloidea (12 species); only 10 species belong to the Diclidophoroidea and 2 of those to the Diclidophoridae. It is concluded that deepsea Monogenea in southeastern Australia show no or very little relationship with surface Monogenea of the same geographical area, but close relationship with Monogenea in the deepsea of other geographical areas. Some deepsea Monogenea have a wide geographical distribution in the Atlantic and Pacific Oceans. Arctic and Antarctic Monogenea also are not related to deepwater forms. The main group of deepsea Monogenea is considered to be archaic. 相似文献
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Biological activity of 125iodine labelled globin mRNA in an Ehrlich ascites cell-free system 总被引:1,自引:0,他引:1
Walter Knöchel 《Molecular biology reports》1974,1(6):311-320
Globin mRNA was isolated from avian erythroblasts and labelled with 125iodine to a specific activity of 4.5×106 dpm μg-1 mRNA. The labelling procedure was modified as compared to common techniques in order to protect the mRNA against degradation. When this RNA is translated in an Ehrlich ascites cell-free system globin chains are synthesized as is demonstrated by the analysis of the in vitro synthesized products. The biological activity of 125iodine labelled mRNA has proven to be 30% of that of unlabelled mRNA. 相似文献
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InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members. 相似文献
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Highly purified feather keratin mRNA, prepared by dissociation of mRNP particles in Na dodecyl sulphate, was translated in a wheat embryo cell-free system with similar efficiency to rabbit globin mRNA and RNA purified from cucumber mosaic virus. The only detectable products of translation of the keratin mRNA were keratin chains, which were identical to native keratin chains as judged by several different criteria. These results support previous conclusions that the keratin mRNA can be obtained in a pure state. 相似文献
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Maureen K. Davidson J. Russell Lindsey Mary B. Brown Gail H. Cassell Gary A. Boorman 《Current microbiology》1983,9(4):205-208
B6C3F1 mice from a hybrid production colony frequently were serologically positive by enzyme-linked immunosorbent assay (ELISA) and consistently negative by culture forMycoplasma pulmonis. Subsequently, 162 mice were obtained and intensively studied using an expanded group of cultural procedures, ELISA, and histopathology. Lesions attributable to mycoplasma infection were not found, butMycoplasma arthritidis was isolated from 20 mice. TheM. pulmonis ELISA was positive (IgM, IgG, or both) in 113 mice. Selected sera were tested simultaneously in both theM. pulmonis ELISA and in an ELISA usingM. arthritidis antigen, and were found to be positive in both the IgM and IgG classes in both ELISAs. Thus, cross-reacting antibody was produced in mice naturally infected withM. arthritidis, confirming previous observations based on experimental infections. To our knowledge, this is the first report of naturalM. arthritidis infection in laboratory mice. 相似文献
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Translation of hepatic mRNA in extracts from wheat germ embryos 总被引:1,自引:0,他引:1
Extracts from wheat embryos have been used to study the incorporation of amino acids into TCA insoluble products using hepatic mRNA fractions. The properties of this system are described and compared to the incorporation obtained with poly U and rabbit globin mRNA. SDS-acrylamide gel analysis showed that the major polypeptide synthesized with globin mRNA co-migrates with rabbit globin (15 500 daltons). Rat liver products were numerous, with molecular weights from less than 10000 to greater than 65000 daltons. The KCl concentration for maximum incorporation into TCA precipitable polypeptides with hepatic mRNA was not the optimum KCl concentration for synthesis of complete products. 相似文献