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81.
Studies of the behaviour of 26 (12 males and 14 females) captive infant and juvenile lowland gorillas showed clear sex differences. Females showed greater interest in young infants and were more active in nest building as well as in solitary and social grooming. Males were more active in locomotive, dominance, and aggressive behaviour and in social play. Hand-rearing further increased aggression. Males were more aggressive when they lived with only one partner, and they rose in rank even above older females, a pattern that has not been observed in naturally reared gorillas.  相似文献   
82.
The study involved 126 patients with cholelithiasis. Set of biochemical, radiological, endoscopic, and ultrasound examinations was carried out in these patients. Potential coincidence of clinical symptoms and causes of so-called postcholecystectomy syndrome was the purpose of a 1-year follow-up studies. The significance of the results are discussed.  相似文献   
83.
A gene designated "FMR-1" has been isolated at the fragile-X locus. One exon of this gene is carried on a 5.1-kb EcoRI fragment that exhibits length variation in fragile-X patients because of amplification of or insertion into a CGG-repeat sequence. This repeat probably represents the fragile site. The EcoRI fragment also includes an HTF island that is hypermethylated in fragile-X patients showing absence of FMR-1 mRNA. In this paper, we present further evidence that the FMR-1 gene is involved in the clinical manifestation of the fragile-X syndrome and also in the expression of the cellular phenotype. A deletion including the HTF island and exons of the FMR-1 gene was detected in a fragile X-negative mentally retarded male who presented the clinical phenotype of the fragile-X syndrome. The deletion involves less than 250 kb of genomic DNA, including DXS548 and at least five exons of the FMR-1 gene. These data support the hypothesis that loss of function of the FMR-1 gene leads to the clinical phenotype of the fragile-X syndrome. In the fragile-X syndrome, there are pathogenetic mechanisms other than amplification of the CGG repeat that do have the same phenotypic consequences.  相似文献   
84.
85.
C Lee  L H Chen  M L Liu    Y C Su 《Applied microbiology》1992,58(10):3419-3422
A 26-mer oligonucleotide specific to Vibrio parahaemolyticus was synthesized from a 1,275-bp thermostable direct hemolysin (tdh) gene. This oligonucleotide probe specifically reacted with DNA from 89 of 95 V. parahaemolyticus isolates but not with DNA from other vibrios or other enteric and nonenteric organisms (n = 48). The probe hybridized with Southern blots of 0.5-kb HindIII-restricted chromosomal DNA fragments from all but five V. parahaemolyticus test isolates. The probe could be used to directly identify V. parahaemolyticus in artificially contaminated food without an isolation step.  相似文献   
86.
本文应用不同的培养基和培养方法对金定鸭盲肠内厌氧菌进行了分离和初步鉴定,结果说明:采用不同厌氧方法对厌氧菌的分离计数具有一定的影响;金定鸭盲肠内厌氧菌群主要有革兰氏阳性无芽孢杆菌、革兰氏阴性无芽孢杆菌、厌氧球菌和梭菌,其中有一株厌氧菌对氧的存在极为敏感。本文中强调了严格遵守厌氧培养和操作条件的重要性。  相似文献   
87.
Abstract: The fibrillogenic properties of Alzheimer's Aβ peptides corresponding to residues 1–40 of the normal human sequence and to two mutant forms containing the replacement Ala21 to Gly or Glu22 to Gln were compared. At pH 7.4 and 37°C the Gln22 peptide was found to aggregate and precipitate from solution faster than the normal Aβ, whereas the Gly21 peptide aggregated much more slowly. Electron microscopy showed that the aggregates all had fibrillar structures. Circular dichroism spectra of these peptides revealed that aggregation of the normal and Gln22 sequences was associated with spectral changes consistent with a transformation from random coil to β sheet, whereas the spectrum of the Gly21 peptide remained almost unchanged during a period in which little or no aggregation occurred. When immobilised by spotting onto nitrocellulose membranes the peptides bound similar amounts of the radioisotope 65Zn2+. Of several competing metal ions, tested at 20× the concentration of Zn2+, Cu2+ displaced >95% of the radioactivity from all three peptides and Ni2+ produced >50% displacement in each case. Some other metal ions tested caused lesser displacement, but Fe2+ and Al3+ were without effect. In a saturation binding assay, a value of 3.2 µM was obtained for the binding of Zn2+ to Aβ but our data provided no evidence for a reported higher affinity site (107 nM). The results suggest that the neuropathology associated with the Gly21 mutation is not due to enhanced fibrillogenic or different metal-binding properties of the peptide and that the binding of zinc to amyloid peptides is not a specific phenomenon.  相似文献   
88.
Molecular phylogenetic analyses using mitochondrial NADH dehydrogenase subunit 5 (ND5) gene sequences representing all 15 species and the majority of subspecies or races of theOhomopterus ground beetles from all over the Japanese archipelago have uncovered a remarkable evolutionary history. Clustering of the species in the molecular phylogenetic tree is linked to their geographic distribution and does not correlate with morphological characters. Taxonomically the same species or the members belonging to the same species-group fall out in more than two different places on the ND5 tree. Evidence has been presented against a possible participation of ancestral polymorphism and random lineage sorting or of hybrid individuals for the observed distribution of mitochondrial DNA haplotypes. The most plausible explanation of our results is that parallel evolution took place in different lineages. Most notably,O. dehaanii, O. yaconinus, andO. japonicus in a lineage reveal almost identical morphology with those of the same species (or subspecies) but belonging to the phylogenetically remote lineages.The nucleotide sequence data reported in this paper will appear in the DDBJ, EMBL, and GenBank nucleotide sequence databases with accession numbers D50711-DD-50733 and D87131-D87186.  相似文献   
89.
Conclusion Scientists and historians have often presumed that the divide between biochemistry and molecular biology is fundamentally epistemological.100 The historiography of molecular biology as promulgated by Max Delbrück's phage disciples similarly emphasizes inherent differences between the archaic tradition of biochemistry and the approach of phage geneticists, the ur molecular biologists. A historical analysis of the development of both disciplines at Berkeley mitigates against accepting predestined differences, and underscores the similarities between the postwar development of biochemistry and the emergence of molecular biology as a university discipline. Stanley's image of postwar biochemistry, with its focus on viruses as key experimental systems, and its preference for following macromolecular structure over metabolism pathways, traced the outline of molecular biology in 1950.Changes in the postwar political economy of research universities enabled the proliferation of disciplines such as microbiology, biochemistry, biophysics, immunology, and molecular biology in universities rather than in medical schools and agricultural colleges. These disciplines were predominantly concerned with investigating life at the subcellular level-research that during the 1930s had often entailed collaboration with physicists and chemists. The interdisciplinary efforts of the 1930s (many fostered by the Rockefeller Foundation) yielded a host of new tools and reagents that were standardized and mass-produced for laboratories after World War II. This commercial infrastructure enabled basic researchers in biochemistry and molecular biology in the 1950s and 1960s to become more independent from physics and chemistry (although they were practicing a physicochemical biology), as well as from the agricultural and medical schools that had previously housed or sponsored such research. In turn, the disciplines increasingly required their practitioners to have specialized graduate training, rather than admitting interlopers from the physical sciences.These general transitions toward greater autonomy for biochemistry and allied disciplines should not mask the important particularities of these developments on each campus. At the University of Caliornia at Berkeley, agriculture had provided, with medicine, significant sponsorship for biochemistry. The proximity of Lawrence and his cyclotrons supported the early development of Berkeley as a center for the biological uses of radioisotopes, particularly in studies of metabolism and photosynthesis. Stanley arrived to establish his department and virus institute before large-scale federal funding of biomedical research was in place, and he courted the state of California for substantial backing by promising both national prominence in the life sciences and virus research pertinent to agriculture and public health. Stanley's venture benefited significantly from the expansion of California's economy after World War II, and his mobilization against viral diseases resonated with the concerns of the Cold War, which fueled the state's rapid growth. The scientific prominence of contemporary developments at Caltech and Stanford invites the historical examination of the significance of postwar biochemistry and molecular biology within the political and cultural economy of the Golden State.In 1950, Stanley presented a persuasive picture of the power of biochemistry to refurbish life science at Berkeley while answering fundamental questions about life and infection. In the words of one Rockefeller Foundation officer,There seems little doubt in [my] mind that as a personality Stanley will be well able to dominate the other personalities on the Berkeley campus and will be able to drive his dream through to completion, which, incidentally, leaves Dr. Hubert [sic] Evans and the whole ineffective Life Sciences building in the somewhat peculiar position of being by-passed by much of the truly modern biochemistry and biophysics research that will be carried out at Berkeley. Furthermore, it seems likely that Dr. S's show will throw Dr. John Lawrence's Biophysics Department strongly in the shade both figuratively and literally, but should make the University of California pre-eminent not only in physics but in biochemistry as well.101 Stanley, Sproul, Weaver, and this officer (William Loomis) all testified to a perceptible postwar opportunity to capitalize on public support for biological research that relied on the technologies from physics and chemistry without being captive to them, and that addressed issues of medicine and agriculture without being institutionally subservient. What is striking, given the expectation by many that Stanley would be able to drive his dream through to completion, was that in fact he did not. Biochemists who had succeeded in making their expertise valued in specialized niches were resistant to giving up their affiliations to joint Stanley's liberated organization. Stanley's failure was not simply due to institutional factors: researchers as well as Rockefeller Foundation officers faulted him for his lack of scientific imagination, which made it difficult for him to gain credibility in leading the field. Moreover, many biochemists did not share Stanley's commitment to viruses as the key material for the new biochemistry.In the end, Stanley's free-standing department did become a first-rate department of biochemistry, but only after freeing itself from Stanley's leadership and his single-minded devotion to viruses. Nonetheless, the falling-out with the Berkeley biochemists was rapidly followed by the establishment of a Department of Molecular Biology, attesting to the unabating economic and institutional possibilities for an authoritative general biology (or two, for that matter) to take hold. In each case, following Stanley's dream sheds light on how the possible and the real shaped the (re)formation of biochemistry and molecular biology as postwar life sciences.  相似文献   
90.
Y Yang  Q Su    J M Wilson 《Journal of virology》1996,70(10):7209-7212
Adenoviruses missing E1 have been used as gene delivery vectors to the lungs for the treatment of cystic fibrosis. Transient expression of the recombinant gene and the development of inflammation have been two major limitations to the application of first-generation recombinant adenoviruses for gene therapy. Studies with mouse models of liver- and lung-directed gene therapy suggested that CD8+ cytotoxic T lymphocytes (CTLs) are effectors that contribute to extinction of transgene expression. The precise antigens responsible for activation of CTLs have not been identified. In this study, we examine the relative contributions of viral proteins versus the transgene product to the activation of CTLs which eliminate transgene-containing cells in mouse lungs. Instillation of a lacZ-expressing virus into the lungs of C57BL/6 mice elicited CTL responses to both viral proteins and the transgene product, beta-galactosidase, which collectively contribute to loss of trans-gene expression in mouse airways. Similar results were obtained in two experimental models in which the animals should be tolerant to the transgene, i.e., lacZ virus delivered to an animal transgenic for lacZ and a virus expressing the liver-specific enzyme ornithine transcarbamylase administered to the lungs of various strains of immune-competent mice. These data confirm the hypothesis that CTLs specific for viral antigens contribute to the problem of transgene instability in mouse lungs and indicate that CTLs specific for transgene product alone cannot account for the observed problem.  相似文献   
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