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61.
A Rhizobium tropici DNA region carrying the amino-terminal half of a nodD gene and a nod-box-like sequence confers host-range extension 总被引:1,自引:0,他引:1
Carolina Sousa Jorge Luis Folch Purificación Boloix Manuel Megías Noreide Nava Carmen Quinto 《Molecular microbiology》1993,9(6):1157-1168
Rhizobium tropici CIAT899 is a broad-host-range strain that, in addition to Phaseolus, nodulates other plant legumes such as Leucaena and Macroptilium. The narrow-host-range of Rhizobium leguminosarum biovars phaseoli (strain CE3) and trifolii (strain RS1051) can be extended to Leucaena esculents and Phaseolus vulgaris plants, respectively, by the introduction of a DNA fragment 521 bp long, which carries 128 amino acids of the amino-terminal region of a nodD gene from R. tropici, as well as a putative nod-box-like sequence, divergently oriented. The 521 bp fragment, in the presence of L. esculenta or P. vulgaris root exudates, induced a R. leguminosarum bv. viciae nodA-lacZ fusion in either a CE3 or RS1051 background, respectively. 相似文献
62.
Investigation of inheritance of chronic inflammatory bowel diseases by complex segregation analysis.
M Orholm L Iselius T I S?rensen P Munkholm E Langholz V Binder 《BMJ (Clinical research ed.)》1993,306(6869):20-24
OBJECTIVE--To investigate the mode of inheritance of ulcerative colitis and Crohn''s disease by complex segregation analysis. DESIGN--Cross sectional population based survey of familial occurrence of chronic inflammatory bowel disease. SETTING--Population of the Copenhagen county in 1987. SUBJECTS--662 patients in whom inflammatory bowel disease had been diagnosed before 1979, of whom 637 (96%) provided adequate information. Of 504 patients with ulcerative colitis, 54 had 77 relatives with ulcerative colitis and of 133 patients with Crohn''s disease, five had seven relatives with Crohn''s disease. MAIN OUTCOME MEASURES--Patterns of segregation of either disease as assessed by complex segregation analysis performed with the computer program POINTER. RESULTS--The analysis suggested that a major dominant gene with a penetrance of 0.20-0.26 is present in 9-13% of adult patients with ulcerative colitis. The analysis did not allow for other components in the familial aggregation. For Crohn''s disease the best fitting model included a major recessive gene with complete penetrance, for which 7% of the patients are homozygous. However, this model was not significantly different from a multifactorial model. CONCLUSIONS--The segregation pattern indicates that a major dominant gene has a role in ulcerative colitis, and suggests that a major recessive gene has a role in Crohn''s disease. 相似文献
63.
Roberto de la Herrán Miguel Hermida Juan Andres Rubiolo Jèssica Gómez-Garrido Fernando Cruz Francisca Robles Rafael Navajas-Pérez Andres Blanco Paula Rodriguez Villamayor Dorinda Torres Pablo Sánchez-Quinteiro Daniel Ramirez Maria Esther Rodríguez Alberto Arias-Pérez Ismael Cross Neil Duncan Teresa Martínez-Peña Ana Riaza Adrian Millán M. Cristina De Rosa Davide Pirolli Marta Gut Carmen Bouza Diego Robledo Laureana Rebordinos Tyler Alioto Carmelo Ruíz-Rejón Paulino Martínez 《Molecular ecology resources》2023,23(4):886-904
Sex determination (SD) shows huge variation among fish and a high evolutionary rate, as illustrated by the Pleuronectiformes (flatfishes). This order is characterized by its adaptation to demersal life, compact genomes and diversity of SD mechanisms. Here, we assembled the Solea senegalensis genome, a flatfish of great commercial value, into 82 contigs (614 Mb) combining long- and short-read sequencing, which were next scaffolded using a highly dense genetic map (28,838 markers, 21 linkage groups), representing 98.9% of the assembly. Further, we established the correspondence between the assembly and the 21 chromosomes by using BAC-FISH. Whole genome resequencing of six males and six females enabled the identification of 41 single nucleotide polymorphism variants in the follicle stimulating hormone receptor (fshr) consistent with an XX/XY SD system. The observed sex association was validated in a broader independent sample, providing a novel molecular sexing tool. The fshr gene displayed differential expression between male and female gonads from 86 days post-fertilization, when the gonad is still an undifferentiated primordium, concomitant with the activation of amh and cyp19a1a, testis and ovary marker genes, respectively, in males and females. The Y-linked fshr allele, which included 24 nonsynonymous variants and showed a highly divergent 3D protein structure, was overexpressed in males compared to the X-linked allele at all stages of gonadal differentiation. We hypothesize a mechanism hampering the action of the follicle stimulating hormone driving the undifferentiated gonad toward testis. 相似文献
64.
Carmen Prez-Martínez Luis Cruz-Pizarro Pedro Snchez-Castillo 《Journal of phycology》1992,28(5):608-615
Growth and sexual reproduction in a population of Cyclotella ocellata Pantocseck were studied during one annual cycle in a reservoir and in short-term enclosure experiments performed in situ involving different nutrient conditions and concentrations of zooplankton species. Three phases of auxosporulation in this diatom were distinguishable morphologically: 1) preauxospore, from the beginning of zygote formation until the valves were longitudinally separated, 2) primary auxospore, when the zygote grew too large to fit inside the valves and before it reached its full size, and 3) mature auxospore, characterized by a well-developed, markedly scalloped edge. Under experimental and natural conditions, sexual reproduction was associated with changes in cell size. In the natural system, the auxospore appeared to act as a resting structure during conditions adverse for population growth. A threshold population of small cells appeared to be necessary for sexual reproduction in the natural system, whereas auxosporulation was associated with phosphorus fertilization in the enclosures. In both environments only cells smaller than 9.5 μm in diameter were capable of auxospore formation. Our results suggest that, once having reached the critical cell size, the factors that trigger sexual reproduction may depend on ambient environmental conditions. 相似文献
65.
66.
Aonio Bernao Isabel Meseguer María Victorina Aguilar María Carmen Martínez Para María José González Mu?oz 《Journal of trace elements in medicine and biology》2004,18(1):33-39
This 12-day study was conducted to evaluate the effects of three different levels of dietary chromium (100, 200, and 500 microg/day) in the form of chromium picolinate (CrPic) on growth and protein use in weaned rats. No significant effect of CrPic on body weight gain, food intake, or food conversion rate was observed. Elevated doses of CrPic seemed to increase muscle mass, either by stimulating protein anabolism by activation of insulin by chromium or by lowering protein degradation. However, these effects had no repercussions on overall growth, suggesting that any anabolic effect of chromium due to the action of insulin was probably marginal. 相似文献
67.
Herbert Essien S. Jason Lai Steven R. Binder David L. King 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,683(2):199
The identification of the metabolite demoxepam in human urine establishes that chlordiazepoxide, a common benzodiazepine, has been administered. Like N-oxide metabolites of other drugs, demoxepam cannot be detected by gas chromatography—mass spectrometry (GC-MS), due to thermal decomposition, and the product, nordiazepam, is a metabolite common to many benzodiazepines. Demoxepam can be readily screened using a high-performance liquid chromatography (HPLC) system such as REMEDi HS; at 35°C, no thermal decomposition will occur. Currently, there is no confirmation method available for the detection of demoxepam in urine samples. In this study, we demonstrated that following collection of the HPLC fraction, demoxepam can be confirmed using the technique of direct-probe MS. The mass spectra of demoxepam and nordiazepam differ and are easily distinguishable from each other. Ten urine samples that were analyzed by HPLC and determined to contain demoxepam were evaluated; demoxepam was confirmed in each case by direct-probe MS. 相似文献
68.
A. Torres-Barragán E. Zavaleta-Mejía Carmen González-Chávez Ronald Ferrera-Cerrato 《Mycorrhiza》1996,6(4):253-257
A field experiment was carried out to determine the effects of the inoculation of onion (Allium cepa L.) with Glomus sp. Zac-19 on the development of onion white rot (Sclerotium cepivorum Berk.) and on onion production. Mycorrhization delayed onion white rot epidemics by 2 weeks and provided a significant protection
against the disease for 11 weeks after onion transplanting, as compared with nonmycorrhizal controls. Mycorrhizal plants showed
an increase of 22% in yield, regardless of the presence of the white rot pathogen.
Accepted: 8 January 1996 相似文献
69.
Leirla Salazar Hafida Fsihi Edda de Rossi Giovanna Riccardi Carmen Rios Stewart T. Cole Howard E. Takiff 《Molecular microbiology》1996,20(2):283-293
The genus Mycobacterium is composed of species with widely differing growth rates ranging from approximately three hours in Mycobacterium smegmatis to two weeks in Mycobacterium leprae. As DNA replication is coupled to cell duplication, it may be regulated by common mechanisms. The chromosomal regions surrounding the origins of DNA replication from M. smegmatis, M. tuberculosis, and M. leprae have been sequenced, and show very few differences. The gene order, rnpA-rpmH-dnaA-dnaN-recF-orf-gyrB-gyrA, is the same as in other Gram-positive organisms. Although the general organization in M. smegmatis is very similar to that of Streptomyces spp., a closely related genus, M. tuberculosis and M. leprae differ as they lack an open reading frame, between dnaN and recF, which is similar to the gnd gene of Escherichia coli. Within the three mycobacterial species, there is extensive sequence conservation in the intergenic regions flanking dnaA, but more variation from the consensus DnaA box sequence was seen than in other bacteria. By means of subcloning experiments, the putative chromosomal origin of replication of M. smegmatis, containing the dnaA-dnaN region, was shown to promote autonomous replication in M. smegmatis, unlike the corresponding regions from M. tuberculosis or M. leprae. 相似文献
70.
Acyl Group Migrations in 2-Monoolein 总被引:6,自引:0,他引:6
Anna Millqvist Fureby Carmen Virto Patrick Adlercreutz Bo Mattiasson 《Biocatalysis and Biotransformation》1996,14(2):89-111
Acyl migration in 2-monoolein dissolved in solvents under conditions common in lipid modification reactions has been studied. The effects on acyl migration of solvent, incubation temperature, water activity, polar additives and solid additives have been investigated. Extensive acyl migration occured in aliphatic hydrocarbons and water-miscible alcohols under dry conditions. The acyl migration rate could be decreased in several nonpolar solvents by adding a small amount of water or an alcohol. Increasing water activity had no effect in isooctane, but decreased the acyl migration rate dramatically in methyl tert-butyl ether and methyl isobutyl ketone. Several commonly used enzyme supports catalysed acyl migration, showing that supports with surface charges could catalyse acyl migration. 相似文献