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Elizabeth M. A. Valleley Christine J. Harrison Yvonne Cook Mark W. J. Ferguson Paul T. Sharpe 《Chromosoma》1994,103(7):502-507
Comparative mapping studies of X-linked genes in mammals have provided insights into the evolution of the X chromosome. Many reptiles including the American alligator, Alligator mississippiensis, do not appear to possess heteromorphic sex chromosomes, and sex is determined by the incubation temperature of the egg during embryonic development. Mapping of homologues of mammalian X-linked genes in reptiles could lead to a greater understanding of the evolution of vertebrate sex chromosomes. One of the genes used in the mammalian mapping studies was ZFX, an X-linked copy of the human ZFY gene which was originally isolated as a candidate for the mammalian testis-determining factor (TDF). ZFX is X-linked in eutherians, but maps to two autosomal locations in marsupials and monotremes, close to other genes associated with the eutherian X. The alligator homologue of the ZFY/ZFX genes, Zfc, has been isolated and described previously. A detailed karyotype of A. mississippiensis is presented, together with chromosomal in situ hybridisation data localising the Zfc gene to chromosome 3. Further chromosomal mapping studies using eutherian X-linked genes may reveal conserved chromosomal regions in the alligator that have become part of the eutherian X chromosome during evolution. 相似文献
3.
Raul J. Cano Jessica Rivera-Perez Gary A. Toranzos Tasha M. Santiago-Rodriguez Yvonne M. Narganes-Storde Luis Chanlatte-Baik Erileen García-Roldán Lucy Bunkley-Williams Steven E. Massey 《PloS one》2014,9(9)
Coprolites are fossilized feces that can be used to provide information on the composition of the intestinal microbiota and, as we show, possibly on diet. We analyzed human coprolites from the Huecoid and Saladoid cultures from a settlement on Vieques Island, Puerto Rico. While more is known about the Saladoid culture, it is believed that both societies co-existed on this island approximately from 5 to 1170 AD. By extracting DNA from the coprolites, followed by metagenomic characterization, we show that both cultures can be distinguished from each other on the basis of their bacterial and fungal gut microbiomes. In addition, we show that parasite loads were heavy and also culturally distinct. Huecoid coprolites were characterized by maize and Basidiomycetes sequences, suggesting that these were important components of their diet. Saladoid coprolite samples harbored sequences associated with fish parasites, suggesting that raw fish was a substantial component of their diet. The present study shows that ancient DNA is not entirely degraded in humid, tropical environments, and that dietary and/or host genetic differences in ancient populations may be reflected in the composition of their gut microbiome. This further supports the hypothesis that the two ancient cultures studied were distinct, and that they retained distinct technological/cultural differences during an extended period of close proximity and peaceful co-existence. The two populations seemed to form the later-day Taínos, the Amerindians present at the point of Columbian contact. Importantly, our data suggest that paleomicrobiomics can be a powerful tool to assess cultural differences between ancient populations. 相似文献
4.
Yunhe Meng Xixi Shao Yan Wang Yumei Li Xiaojian Zheng Gongyuan Wei Seon-Won Kim Chonglong Wang 《Biotechnology and bioengineering》2020,117(11):3499-3507
Squalene is a lipophilic and non-volatile triterpene with many industrial applications for food, pharmaceuticals, and cosmetics. Metabolic engineering focused on optimization of the production pathway suffer from little success in improving titers because of a limited space of the cell membrane accommodating the lipophilic product. Extension of cell membrane would be a promising approach to overcome the storage limitation for successful production of squalene. In this study, Escherichia coli was engineered for squalene production by overexpression of some membrane proteins. The highest production of 612 mg/L was observed in the engineered E. coli with overexpression of Tsr, a serine chemoreceptor protein, which induced invagination of inner membrane to form multilayered structure. It was also observed an increase in unsaturated fatty acid in membrane lipids composition, suggesting cellular response to maintain membrane fluidity against squalene accumulation in the engineered strain. This study potentiates the capability of E. coli for squalene production and provides an effective strategy for the enhanced production of such compounds. 相似文献
5.
Chimerization of antibodies (Ab) by cloning the V (variable) regions encoding the light and heavy chains with degenerate oligodeoxyribonucleotide primers matching to framework region 1 and to the joining regions, leads to Ab with altered amino acids at the N-terminus compared to those of the parental Ab. This is due to N-terminal framework 1 sequences in the expression vectors [Larrick et al., Bio/Technology 7 (1989) 937-938; Le Boeuf et al., Gene (1989) 371-377; Orlandi et al., Proc. Natl. Acad. Sci. USA 86 (1989) 3833-3837]. This might lead to Ab with altered affinity to the antigen due to interaction of framework sequences with complementarity determining regions. Moreover, some V regions may be refractory to cloning by this procedure. Here, we describe a method to circumvent these potential problems. The V regions for both chains of the Ab are cloned by inverse polymerase chain reaction (PCR) with primers matching the known constant region sequences of the Ab. After sequencing, PCR fragments corresponding to the V regions of both chains are inserted in-frame into appropriate expression vectors leading to Ab with unaltered N-terminal sequences after expression in mammalian cells. The procedure is illustrated with an Ab directed against the beta chain of the human interleukin-2 receptor. 相似文献
6.
Yvonne Grimm-Jørgensen S.E. Pfeiffer J.F. McKelvy 《Biochemical and biophysical research communications》1976,70(1):167-173
Immunoreactive thyrotropin releasing factor (TRF) was detected in homogenates of two clonal cell lines, BN1010-1 and BN1010-3, derived from a rat central nervous system tumor. TRF was present in logarithmically-growing cells; daily medium changes with slightly acid culture medium (pH 6.8) greatly increased the TRF content of these cells. In contrast, TRF could not be detected in stationary phase cells. TRF peptidases were <1% as active in homogenates of BN1010 cells as those in homogenates of guinea pig brain or hypothalamus. It is expected that these cells will provide an excellent model system for the study of various aspects of TRF metabolism. 相似文献
7.
8.
Mapping of FMR1, the gene implicated in fragile X-linked mental retardation, on the mouse X chromosome 总被引:2,自引:0,他引:2
A genetic map of the Cf-9 to Dmd region of the mouse X chromosome has been established by typing 100 offspring from a Mus musculus x Mus spretus interspecific backcross for the four loci Cf-9, Cdr, Gabra3, and Dmd. The following order and genetic distances in centimorgans were determined: (Cf-9)-2.4 +/- 1.7-(Cdr)-2.0 +/- 1.4-(Gabra3)-4.1 +/- 2.0-(Dmd). Six backcross offspring carrying X chromosomes with recombination events in the Cdr-Dmd region were identified. These recombination events were used to define the position of Fmr-1, the murine homologue of FMR1, which is the gene implicated in the fragile X syndrome in man, and that of DXS296h, the murine homologue of DXS296. Both Fmr-1 and DXS296h were mapped into the same recombination interval as Gabra3 on the mouse X chromosome. These findings provide strong support for the concept that the order of loci lying in the Cf-9 to Gabra3 segment of the X chromosome is highly conserved between human and mouse. 相似文献
9.
Yvonne Edwards S. Lynn McMillan Cay Kielty Marie-Anne Shaw 《Biochemical genetics》1985,23(5-6):405-422
Our previous studies using rodent/human somatic-cell hybrids suggested that the expression of human mitochondrial glycerol-3-phosphate dehydrogenase (GPDM) is dependent on the presence of human mitochondria. This has now been tested directly by analysis of GPDM activity in a series of nine hybrid-cell lines, four segregating human chromosomes and five losing rodent chromosomes (reverse segregants). The chromosome composition of the hybrids was deduced from analysis of biochemical markers and examination of G- and G11-banded metaphase spreads and the mitochondrial content was determined by Southern blot analysis, using cloned mouse and human mtDNA sequences as probes. We found that the mtDNA species present in these hybrids correlated exactly with the pattern of chromosome segregation such that the conventional hybrids contained rodent mtDNA and the reverse segregants human mtDNA. However, the pattern of GPDM expression was not directly correlated with the species of chromosomes or mitochondria present: all the hybrids showed strong rodem GPDM activity and two from each class of hybrid also showed human GPDM activity but the other hybrids were negative for human GPDM. We conclude that rodent GPDM readily integrates into human mitochondria, that the expression of rodent GPDM is not dependent on the presence of rodent mitochondria, and that GPDM is not coded by mtDNA. Human GPDM either is not capable of being inserted into the rodent mitochondrial membrane or is regulated in some way in the hybrid cells by an unidentified rodent factor. 相似文献
10.
Yvonne H. Edwards Sue Povey Kay M. Levan Catherine E. Driscoll Jose Luis Millan Erwin Goldberg 《Genesis (New York, N.Y. : 2000)》1987,8(4):219-232
From the data presented in this report, the human LDHC gene locus is assigned to chromosome 11. Three genes determine lactate dehydrogenase (LDH) in man. LDHA and LDHB are expressed in most somatic tissues, while expression of LDHC is confined to the germinal epithelium of the testes. A human LDHC cDNA clone was used as a probe to analyze genomic DNA from rodent/human somatic cell hybrids. The pattern of bands with LDHC hybridization is easily distinguished from the pattern detected by LDHA hybridization, and the LDHC probe is specific for testis mRNA. The structural gene LDHA has been previously assigned to human chromosome 11, while LDHB maps to chromosome 12. Studies of pigeon LDH have shown tight linkage between LDHB and LDHC leading to the expectation that these genes would be syntenic in man. However, the data presented in this paper show conclusively that LDHC is syntenic with LDHA on human chromosome 11. The terminology for LDH genes LDHA, LDHB, and LDHC is equivalent to Ldhl, Ldh2, and Ldh3, respectively. 相似文献