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51.
A Common Region of Deletion on Chromosome 17q in Both Sporadic and Familial Epithelial Ovarian Tumors Distal to BRCA1 总被引:2,自引:1,他引:1
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Andrew K. Godwin Lisa Vanderveer David C. Schultz Henry T. Lynch Deborah A. Altomare Kenneth H. Buetow Mary Daly Lori A. Getts Agnes Masny Norman Rosenblum Michael Hogan Robert F. Ozols Thomas C. Hamilton 《American journal of human genetics》1994,55(4):666-677
Linkage analysis in familial breast and ovarian cancer and studies of allelic deletion in sporadic ovarian tumors have identified a region on chromosome 17q containing a candidate tumor-suppressor gene (referred to as BRCA1) of likely importance in ovarian carcinogenesis. We have examined normal and tumor DNA samples from 32 patients with sporadic and 8 patients with familial forms of the disease, for loss of heterozygosity (LOH) at 21 loci on chromosome 17 (7 on 17p and 14 on 17q). LOH on 17p was 55% (22/40) for informative 17pl3.1 and 17pl3.3 markers. When six polymorphic markers flanking the familial breast/ovarian cancer susceptibility locus on 17ql2-q21 were used, LOH was 58% (23/40), with one tumor showing telomeric retention. Evaluation of a set of markers positioned telomeric to BRCA1 resulted in the highest degree of LOH, 73% (29/40), indicating that a candidate locus involved in ovarian cancer may reside distal to BRCA1. Five of the tumors demonstrating allelic loss for 17q markers were from individuals with a strong family history of breast and ovarian cancer. More important, two of these tumors (unique patient number [UPN] 57 and UPN 79) retained heterozygosity for all informative markers spanning the BRCA1 locus but showed LOH at loci distal to but not including the anonymous markers CMM86 (D17S74) and 42D6 (D17S588), respectively. Deletion mapping of seven cases (two familial and five sporadic) showing limited LOH on 17q revealed a common region of deletion, distal to GH and proximal to D17S4, that spans −25 cM. These results suggest that a potential tumor-suppressor gene involved in both sporadic and familial ovarian cancer may reside on the distal portion of chromosome 17q and is distinct from the BRCA1 gene. 相似文献
52.
Increased biomass production in terrestrial ecosystems with elevated atmospheric CO2 may be constrained by nutrient limitations as a result of increased requirement or reduced availability caused by reduced
turnover rates of nutrients. To determine the short-term impact of nitrogen (N) fertilization on plant biomass production
under elevated CO2, we compared the response of N-fertilized tallgrass prairie at ambient and twice-ambient CO2 levels over a 2-year period. Native tallgrass prairie plots (4.5 m diameter) were exposed continuously (24 h) to ambient
and twice-ambient CO2 from 1 April to 26 October. We compared our results to an unfertilized companion experiment on the same research site. Above-
and belowground biomass production and leaf area of fertilized plots were greater with elevated than ambient CO2 in both years. The increase in biomass at high CO2 occurred mainly aboveground in 1991, a dry year, and belowground in 1990, a wet year. Nitrogen concentration was lower in
plants exposed to elevated CO2, but total standing crop N was greater at high CO2. Increased root biomass under elevated CO2 apparently increased N uptake. The biomass production response to elevated CO2 was much greater on N-fertilized than unfertilized prairie, particularly in the dry year. We conclude that biomass production
response to elevated CO2 was suppressed by N limitation in years with below-normal precipitation. Reduced N concentration in above- and belowground
biomass could slow microbial degradation of soil organic matter and surface litter, thereby exacerbating N limitation in the
long term. 相似文献
53.
Summary Fructokinase negativeZymomonas mobilis UQM 2864, was co-immobilised with invertase in alginate and incubated on sucrose-based media in batch and fedbatch culture. The highest fructose concentration achieved was 138 g/l using fed-batch cultivation with sugar-cane syrup-simultaneously producing 79.9 g/l or 10.1% (v/v) ethanol in less than 24 hours. The ethanol and fructose yields were 95 and 84% respectively. Co-immobilisation resulted in faster fermentation times, particularly for the batch fermentations, and complete utilisation of substrate. 相似文献
54.
Lisa T. Garber R. Curtis Haltiwanger Drake S. Eggleston 《Letters in Peptide Science》1994,1(3):127-133
Summary Continuing a line of investigations on methods for formation and growth of high-quality crystals of peptides, the glycylglycine sequence has been crystallized by evaporation methods as a salt with 1,5-naphthalenedisulfonic acid. The structure of the peptide is highly extended, and is conformationally quite similar to the structures which have been characterized for other zwitterionic and salt forms of this sequence. Thus, crystallization as a salt with this sulfonic acid has imposed no undue influence upon the molecular conformation. These results offer further indication that the preparation of peptide sulfonate salts, particularly with arene templates, may have broad general utility for crystallization of interesting sequences which until now have not been approachable in their zwitterionic forms. 相似文献
55.
Marianne Schwartz Maria Anvret Mireille Claustres Hans Geir Eiken Kristin Eiklid Charlotte Schaedel Lisa Stolpe Lisbeth Tranebjærg 《Human genetics》1994,93(2):157-161
In a systematic screening for mutations in the gene encoding the cystic fibrosis transmembrane regulator among Danish cystic fibrosis (CF) patients, we identified a mutation in exon 3 (394delTT); this mutation was found to be relatively common in Denmark. We therefore screened for 394delTT in Sweden and Norway, where it turned out to be the second most frequent mutation, accounting for 4% of all CF mutations. It also occurs with a high frequency in Finland, but has not been found in larger surveys of mutations in the CFTR gene. Thus, 394delTT seems to be a specific Nordic CF mutation. 相似文献
56.
Lisa L. Kohring David B. Ringelberg Richard Devereux David A. Stahl Marc W. Mittelman David C. White 《FEMS microbiology letters》1994,119(3):303-308
Abstract Twenty-five isolates of dissimilatory sulfate-reducing bacteria were clustered based on similarity analysis of their phospholipid ester-linked fatty acids (PLFA). Of these, 22 showed that phylogenetic relationships based on the sequence similarity of their 16S rRNA directly paralleled the PLFA relationships. Desulfobacter latus and Desulfobacter curvatus grouped with the other Desulfobacter spp. by 16S rRNA comparison but not with the PLFA analysis as they contained significantly more monoenoic PLFA than the others. Similarly, Desulfovibrio africanus clustered with the Desulfovibrio spp. by 16S rRNA but not with them when analyzed by PLFA patterns because of higher monoenoic PLFA content. Otherwise, clustering obtained with either analysis was essentially congruent. The relationships defined by PLFA patterns appeared robust to shifts in nutrients and terminal electron acceptors. Additional analyses utilizing the lipopolysaccharide-lipid A hydroxy fatty acid patterns appeared not to shift the relationships based on PLFA significantly except when completely absent, as in Gram-positive bacteria. Phylogenetic relationships between isolates defined by 16S rRNA sequence divergence represent a selection clearly different from the multi-enzyme activities responsible for the PLFA patterns. Determination of bacterial relationships based on different selective pressures for various cellular components provides more clues to evolutionary history leading to a more rational nomenclature. 相似文献
57.
Jeffrey A. Banas Daniel Simon Lisa K. Williams Joseph J. Ferretti Roy R.B. Russell 《FEMS microbiology letters》1994,123(3):349-354
Abstract A glucosyltransferase (GTF) gene, designated gtfL , from Streptococcus salivarius was cloned and expressed in Escherichia coli and its nucleotide sequence determined. The GTF-L enzyme catalysed the synthesis of water-insoluble glucan in a primer-independent manner. The nucleotide sequence and derived amino acid sequence of GTF-L were similar in size and domain structure to previously sequenced glucosyltransferases. However, a 464-bp region of high variability was identified which could be selectively amplified from strains of S. salivarius by the polymerase chain reaction and could therefore form the basis for species identification. No sequence-specific motifs related to the solubility and linkage of the glucan product or its need for a dextran primer could be ascertained. 相似文献
58.
Two satellite DNAs, designated CapA and CapB, were isolated from the neotropical primate,Cebus apella. The satellites exhibit nonoverlapping distributions onC. apella chromosomes. CapA is a major component of interstitial regions of constitutive heterochromatin, a very large block of heterochromatin comprising most of the long arm of chromosome 11, and some telomeres. The CapA monomer has a length of about 1500 bp and appears recently to have undergone an amplification episode in theC. apella genome. CapA-like sequences are probably present in members of the family Cebidae (to whichC. apella belongs), but not in members of the family Callitrichidae (marmosets). CapB sequences can be detected at the centromeres of manyC. apella chromosomes, and similar sequences are present in all neotropical primates. The 342 bp CapB monomer shares 60%–64% sequence identity with several alpha satellite sequences of human origin. Because of its structure, sequence, and location, it appears that CapB is the New World primate homolog of Old World primate alpha satellite DNA. 相似文献
59.
Renee Ford Geng Wang Parissa Jannati Douglas Adler Peter Racanelli Paul J. Higgins Lisa Staiano-Coico 《Experimental cell research》1993,206(2)
Expression of SPARC (secreted protein acidic and rich in cysteine), a 43-kDa extracellular matrix-associated glycoprotein involved in tissue remodeling, was quantitated during normal human keratinocyte (NHK) growth in culture and as a function of sodium n-butyrate (NaB)-induced differentiation to mature enucleate cornified envelopes (CEs). Low levels of SPARC expression were observed in the basal-like cells of control NHKs, with isolated cells showing intense SPARC expression on the ventral surface. After addition of NaB, SPARC expression increased and the pattern of expression shifted to one involving predominantly suprabasal cells (i.e., spinous cells, pre-CEs, and mature CEs). Dense deposits of SPARC often surrounded the mature CEs. Flow cytometric analysis indicated that approximately 13% of NHKs expressed SPARC within 24 h of seeding into culture. This fraction of SPARC+ cells increased with time and peaked immediately postconfluence (31.3 ± 6.3% SPARC+). Cellular SPARC expression then decreased to baseline levels during entrance into plateau phase growth. SPARC was detectable in all phases of the cell cycle. SPARC levels were more intense and heterogeneous within the G2/M and G1 phases while S phase cells exhibited relatively homogeneous, low intensity, SPARC expression. During NaB-induced NHK differentiation, SPARC intracellular content increased prior to the onset of CE formation (i.e., 2 days after its addition) followed by a period of extracellular accumulation which coincided with the time of maximal CE generation (i.e., Days 4 and 5 after NaB addition). Correlation of cell size with anti-SPARC immunoreactivity revealed a predominance of SPARC expression in cells with a suprabasal phenotype. NHKs cultured on fibronectin (FN), an established modulator of epidermal cell maturation in vitro, showed a similar response to NaB. In general, however, the level of NaB-induced SPARC expression was considerably reduced in FN cultures correlating with a lower efficiency of CE formation. Induced SPARC expression was, in large part, dependent on autocrine transforming growth factor-β (TGF-β) production since incubation in the presence of NaB + neutralizing antibodies to TGF-β inhibited both the expression of SPARC by 72% and development of mature CEs. 相似文献
60.
Hubloher Josephine Joy Van der Sande Lisa Schaudinn Christoph Müller Volker Averhoff Beate 《International microbiology》2023,26(3):543-550
International Microbiology - Acinetobacter baumannii is an opportunistic human pathogen that has become a global threat to healthcare institutions. This Gram-negative bacterium is one of the most... 相似文献