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81.
82.
R.Lucille Roberts Amy Zullo Eric A. Gustafson C.Sue Carter 《Hormones and behavior》1996,30(4):576-582
This experiment was designed to examine the hypothesis that perinatal manipulation of gonadal or adrenal steroids can alter the subsequent expression of juvenile parental (alloparenting) and affiliative behavior in prairie voles (Microtus ochrogaster). Corticosterone (PRECORT), testosterone (PRE-TP), or oil injections (PRESES) were given on Prenatal Days 12–20 or on Postnatal Days 1–6 (CORT6, TP6, or SES6, respectively). Alloparenting was reduced significantly in females in the CORT6 group and in males in the TP6 group. Sibling affiliative preferences were increased significantly in PRE-TP females and stranger preferences were increased in TP6 and CORT6 females. The results suggest timing is a critical factor determining whether hormones have a facilitative or inhibitory effect on alloparental and affiliative behavior in prairie voles. In this species, corticosterone and testosterone have similar organizational effects on affiliative behavior in females. Alloparental behavior is inhibited by postnatal corticosterone administration in females and by postnatal testosterone administration in males, whereas prenatal steroid administration had no significant effect on alloparenting in either gender. 相似文献
83.
The nucleotide sequence of a linear plasmid of Borrelia burgdorferi reveals similarities to those of circular plasmids of other prokaryotes. 总被引:3,自引:0,他引:3 下载免费PDF全文
A linear plasmid of Borrelia burgdorferi had 16,927 bp, a G+C content of 23.1%, a relative deficiency of CpG dinucleotides, and open reading frames A to O. The OrfC and OrfE proteins were similar to hypothetical proteins encoded by circular plasmids of B. burgdorferi. The OrfM and OrfN proteins were similar to replication proteins of circular plasmids of other bacteria. 相似文献
84.
Elizabeth A. Kingsley Teresa E. Carter Kevin D. Barrow Pamela J. Russell 《Cancer immunology, immunotherapy : CII》1996,41(6):348-354
A monoclonal antibody, BLCA-8, was raised against the human bladder cancer cell line, UCRU-BL-17CL. By flow cytometry and immunoperoxidase staining, this antibody was found to possess high specificity for bladder tumours, some reactivity with fetal tissues, and no reactivity with normal bladder, or any normal or malignant tissue. This high specificity and the stability of the antigen to the urinary environment suggest that BLCA-8 may have potential for use as an anti-bladder-cancer therapeutic agent. By thin-layer chromatography and autoradiography, BLCA-8 was found to bind four components within the neutral lipid fraction of a bladder cancer cell line, UCRU-BL-17/23. These components hadR
F values of 0.22, 0.16/0.15 (doublet), 0.12 and 0.08, and migrated below globoside, indicating the presence of more than four sugars. By enzyme-linked immunosorbant assay and thin-layer chromatography it was found that the binding of BLCA-8 to the lipid extract was increased by both mild alkaline hydrolysis and enzymatic treatments, indicating that adjacent phospholipids and glycolipids interfere with the accessibility of the antibody-binding site. Full biochemical characterisation of the BLCA-8 antigen is currently underway. 相似文献
85.
86.
Fifteen ancestral genotypes of United States soybean cultivars were screened for differences in photosynthetic electron transport capacity using isolated thylakoid membranes. Plants were grown in controlled environment chambers under high or low irradiance conditions. Thylakoid membranes were isolated from mature leaves. Photosynthetic electron transport was assayed as uncoupled Hill activity using 2,6-dichlorophenolindophenol (DCIP). Soybean electron transport activity was dependent on genotype and growth irradiance and ranged from 6 to 91 mmol DCIP reduced [mol chlorophyll]–1 s–1. Soybean plastocyanin pool size ranged from 0.1 to 1.3 mol plastocyanin [mol Photosystem I]–1. In contrast, barley and spinach electron transport activities were 140 and 170 mmol DCIP reduced [mol chlorophyll]–1 s–1, respectively, with plastocyanin pool sizes of 3 to 4 mol plastocyanin [mol Photosystem I]–1. No significant differences in the concentrations of Photosystem II, plastoquinone, cytochrome b6f complexes, or Photosystem I were observed. Thus, genetic differences in electron transport activity were correlated with plastocyanin pool size. The results suggested that plastocyanin pool size can vary significantly and may limit photosynthetic electron transport capacity in certain species such as soybean. Soybean plastocyanin consisted of two isoforms with apparent molecular masses of 14 and 11 kDa, whereas barley and spinach plastocyanins each consisted of single polypeptides of 8 and 12 kDa, respectively.Abbreviations DAP
days after planting
- DCIP
2,6-dichlorophenolindophenol
- LiDS
lithium dodecyl sulfate
- PPFD
photosynthetic photon flux density (mol photons m–2 s–1)
- PS I
Photosystem I
- PS II
Photosystem II
- P700
reaction center of Photosystem I
The US Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. 相似文献
87.
A splicing-dependent regulatory mechanism that detects translation signals. 总被引:32,自引:3,他引:29 下载免费PDF全文
Premature termination codons (PTCs) can cause the decay of mRNAs in the nuclear fraction of mammalian cells. This enigmatic nuclear response is of interest because it suggests that translation signals do not restrict their effect to the cytoplasm, where fully assembled ribosomes reside. Here we examined the molecular mechanism for this putative nuclear response by using the T-cell receptor-beta (TCR-beta) gene, which acquires PTCs as a result of programmed rearrangements that occur during normal thymic ontogeny. We found that PTCs had little or no measurable effect on TCR-beta pre-mRNA levels, but they sharply depressed TCR-beta mature mRNA levels in the nuclear fraction of stably transfected cells. A PTC split by an intron was able to trigger the down-regulatory response, implying that PTC recognition occurs after an mRNA is at least partially spliced. However, intron deletion and addition studies demonstrated that a PTC must be followed by at least one functional (spliceable) intron to depress mRNA levels. One explanation for this downstream intron-dependence is that cytoplasmic ribosomes adjacent to nuclear pores scan mRNAs still undergoing splicing as they emerge from the nucleus. We found this explanation to be unlikely because PTCs only 8 or 10 nt upstream of a terminal intron down-regulated mRNA levels, even though this distance is too short to permit PTC recognition in the cytoplasm prior to the splicing of the downstream intron in the nucleus. Collectively, the results suggest that nonsense codon recognition may occur in the nucleus. 相似文献
88.
Molecular markers associated with seed weight in two soybean populations 总被引:10,自引:0,他引:10
M. A. R. Mian M. A. Bailey J. P. Tamulonis E. R. Shipe T. E. Carter Jr. W. A. Parrott D. A. Ashley R. S. Hussey H. R. Boerma 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(7):1011-1016
Seed weight (SW) is a component of soybean, Glycine max (L.) Merr., seed yield, as well as an important trait for food-type soybeans. Two soybean populations, 120 F4-derived lines of YoungxPI416937 (Pop1) and 111 F2-derived lines of PI97100xCoker 237 (Pop2), were mapped with RFLP makers to identify quantitative trait loci (QTLs) conditioning SW across environments and populations. The genetic map of Pop1 consisted of 155 loci covering 973 cM, whereas Pop2 involved 153 loci and covered 1600 cM of map distance. For Pop1, the phenotypic data were collected from Plains, GA., Windblow, N.C., and Plymouth, N.C., in 1994. For Pop2, data were collected from Athens, GA., in 1994 and 1995, and Blackville, S.C., in 1995. Based on single-factor analysis of variance (ANOVA), seven and nine independent loci were associated with SW in Pop1 and Pop2, respectively. Together the loci explained 73% of the variability in SW in Pop1 and 74% in Pop2. Transgressive segregation occurred among the progeny in both populations. The marker loci associated with SW were highly consistent across environments and years. Two QTLs on linkage group (LG) F and K were located at similar genomic regions in both populations. The high consistency of QTLs across environments indicates that effective marker-assisted selection is feasible for soybean SW. 相似文献
89.
Tetrasomy 15q: two marker chromosomes with no detectable alpha-satellite DNA. 总被引:8,自引:3,他引:5 下载免费PDF全文
E. Blennow H. Telenius D. de Vos C. Larsson P. Henriksson O. Johansson N. P. Carter M. Nordenskjld 《American journal of human genetics》1994,54(5):877-883
Two patients with specific and similar phenotypes were both found to have an unusual marker chromosome present in 70%-80% of their lymphocytes at routine cytogenetic examination. The marker chromosomes were isolated by flow sorting and were amplified by degenerate oligonucleotide-primed PCR. These libraries and a cosmid probe located at 15q26 were used to characterize the marker chromosomes by FISH. Both marker chromosomes were found to consist of duplicated chromosome material from the distal part of chromosome 15q and were identified as inv dup(15) (qter-->q23::q23-->qter) and inv dup(15) (qter-->q24::q24-->qter), respectively. Hence, the markers did not include any known centromere region, and no alpha-satellite DNA could be detected at the site of the primary constriction. Tetrasomy 15q may be a new syndrome, associated with a specific type of marker chromosome. In addition, further analyses of this type of marker chromosome might give new insight into the structure and function of the mammalian centromere. 相似文献
90.
Abstract: We have studied the regional distribution and characteristics of polyamine-sensitive [3H]ifenprodil binding sites by quantitative autoradiography in the rat brain. In forebrain areas ifenprodil displaced [3H]ifenprodil (40 nM) in a biphasic manner with IC50 values ranging from 42 to 352 nM and 401 to 974 µM. In hindbrain regions, including the cerebellum, ifenprodil displacement curves were monophasic with IC50 values in the high micromolar range. Wiping studies using forebrain slices (containing both high- and low-affinity sites) or cerebellar slices (containing only the low-affinity site) showed that high- and low-affinity ifenprodil sites are sensitive to spermine and spermidine, to the aminoglycoside antibiotics neomycin, gentamicin, and kanamycin, and to zinc. Two calmodulin antagonists, W7 and calmidazolium, also displaced [3H]ifenprodil from both sites. Other calmodulin antagonists, including trifluoperazine, prenylamine, and chlorpromazine, selectively displaced [3H]ifenprodil from its low-affinity site in hindbrain and forebrain regions. High-affinity [3H]ifenprodil sites, defined either by ifenprodil displacement curves or by [3H]ifenprodil binding in the presence of 1 mM trifluoperazine, were concentrated in the cortex, hippocampus, striatum, and thalamus with little or no labeling of hindbrain or cerebellar regions. This distribution matches that of NMDAR2B mRNA, supporting data showing that ifenprodil has a preferential action at NMDA receptors containing this subunit. Low-affinity [3H]ifenprodil sites have a more ubiquitous distribution but are especially concentrated in the molecular layer of the cerebellum. [3H]Ifenprodil was found to bind to calmodulin-agarose with very low affinity (IC50 of ifenprodil = 516 µM). This binding was displaced by calmodulin antagonists and by polyamines, with a potency that matched their displacement of [3H]ifenprodil from its low-affinity site in brain sections. However, the localization of the low-affinity [3H]ifenprodil site does not strictly correspond to that of calmodulin, and its identity remains to be further characterized. The restricted localization of high-affinity [3H]ifenprodil binding sites to regions rich in NMDAR2B subunit mRNA may explain the atypical nature of this NMDA antagonist. 相似文献