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91.
Jonathan C. Fox Judith L. Swain 《In vitro cellular & developmental biology. Animal》1993,29(3):228-230
Summary Fibroblast growth factors (FGFs) are potent inhibitors of myogenic differentiation. The recent observation that the endogenous
expression of acidic and basic FGF by myogenic cells decreases coordinately with differentiation suggests a regulatory role
for these growth factors in myogenesis. Inasmuch as other proteins known to influence myogenesis (e.g., MyoD1 and myogenin)
activate their own expression as well as the expression of other members of their family, we hypothesized that the FGFs might
be capable of similar autoregulation. We examined the effect of exogenously supplied FGF on the abundance of the mRNAs encoding
acidic and basic FGF in Sol 8 myoblasts, and demonstrate that either acidic or basic FGF stimulate, through paracrine mechanisms,
the accumulation of the mRNAs encoding both of these FGFs. Thus FGFs can auto- and transregulate their own expression in a
manner analogous to that observed for the myogenic determination proteins. In addition, similar to that previously observed
for MyoD1, both acidic and basic FGF suppress myogenin expression in myoblasts. These results suggest two mechanisms whereby
endogenously produced FGFs participate in the maintenance of the undifferentiated state of myogenic cells. These data provide
support for paracrine, and suggest potential autocrine, roles for FGFs in the regulation of myogenic differentiation. 相似文献
92.
Summary DNA fingerprints generated by the Jeffreys' probes, 33.6 and 33.15, indicated the presence of minisatellite-like sequences
in the red clover genome. The fingerprints generated by probe 33.6 gave less background and fewer but better defined bands
than those obtained with probe 33.15. Assay of a regenerative somaclonal variant (F49R) by DNA fingerprinting with probe 33.6
detected mutation that was unlinked to the regenerative trait. The fingerprints obtained under the applied conditions also
demonstrated genetic stability of consecutive generations of the regenerants in tissue culture. DNA fingerprints of F1 plants revealed that each polymorphic band was inherited from either one or the other parent. Both probes distinguished individual-specific
genotypes in seven cultivars of red clover. Greater variability in DNA fingerprints was detected between (V=0.899) than within
(0.417≤V≤0.548) cultivars. 相似文献
93.
94.
Juliane Pereira-Ribeiro Thais Linause Átilla C. Ferreguetti Jonathan Cozer Helena G. Bergallo Carlos Frederico D. Rocha 《Austral ecology》2023,48(7):1405-1412
Stream-dwelling amphibians' occurrence, behaviour and reproductive success are strongly influenced by dynamic abiotic factors, for example, water flow and spray. These factors can disproportionately affect these frogs due to their dependency on specific favourable conditions for development and incapacity to disperse from unfavourable environments. We analysed the influence of environmental covariates on the detectability of Crossodactylus gaudichaudii, an amphibian species endemic to streams in the Brazilian Atlantic Forest. We conducted sampling in the streams of the Duas Bocas Biological Reserve, Brazil, and we measured air and water temperature, air humidity and pH of water on each sampling occasion. We estimated the effects of variables on the detectability of the species using single-season occupancy models. Our results indicated that the detectability of the species increases on occasions with higher water temperatures (24–26°C) and lower pH (5.0–5.5). We investigated the influence of these covariates only on the detectability of adult frogs, but it is likely that the physiochemical properties of stream water are more important to aquatic larvae, and hence, the probability of their detection. Given this, further studies should examine the relevance of covariates on the detectability of adult frogs as well as larvae. 相似文献
95.
Pulkit Singh Wanyi Lu Zunli Lu Adam B. Jost Kimberly Lau Aviv Bachan Bas van de Schootbrugge Jonathan L. Payne 《Geobiology》2023,21(2):175-192
The end-Triassic biodiversity crisis was one of the most severe mass extinctions in the history of animal life. However, the extent to which the loss of taxonomic diversity was coupled with a reduction in organismal abundance remains to be quantified. Further, the temporal relationship between organismal abundance and local marine redox conditions is lacking in carbonate sections. To address these questions, we measured skeletal grain abundance in shallow-marine limestones by point counting 293 thin sections from four stratigraphic sections across the Triassic/Jurassic boundary in the Lombardy Basin and Apennine Platform of western Tethys. Skeletal abundance decreased abruptly across the Triassic/Jurassic boundary in all stratigraphic sections. The abundance of skeletal organisms remained low throughout the lower-middle Hettangian strata and began to rebound during the late Hettangian and early Sinemurian. A two-way ANOVA indicates that sample age (p < .01, η2 = 0.30) explains more of the variation in skeletal abundance than the depositional environment or paleobathymetry (p < .01, η2 = 0.15). Measured I/Ca ratios, a proxy for local shallow-marine redox conditions, show this same pattern with the lowest I/Ca ratios occurring in the early Hettangian. The close correspondence between oceanic water column oxygen levels and skeletal abundance indicates a connection between redox conditions and benthic organismal abundance across the Triassic/Jurassic boundary. These findings indicate that the end-Triassic mass extinction reduced not only the biodiversity but also the carrying capacity for skeletal organisms in early Hettangian ecosystems, adding to evidence that mass extinction of species generally leads to mass rarity among survivors. 相似文献
96.
Lisong Hu Zhongping Xu Rui Fan Guanying Wang Fuqiu Wang Xiaowei Qin Lin Yan Xunzhi Ji Minghui Meng Soonliang Sim Wei Chen Chaoyun Hao Qinghuang Wang Huaguo Zhu Shu Zhu Pan Xu Hui Zhao Keith Lindsey Henry Daniell Jonathan F. Wendel Shuangxia Jin 《Plant biotechnology journal》2023,21(1):78-96
Zanthoxylum armatum and Zanthoxylum bungeanum, known as ‘Chinese pepper’, are distinguished by their extraordinary complex genomes, phenotypic innovation of adaptive evolution and species-special metabolites. Here, we report reference-grade genomes of Z. armatum and Z. bungeanum. Using high coverage sequence data and comprehensive assembly strategies, we derived 66 pseudochromosomes comprising 33 homologous phased groups of two subgenomes, including autotetraploid Z. armatum. The genomic rearrangements and two whole-genome duplications created large (~4.5 Gb) complex genomes with a high ratio of repetitive sequences (>82%) and high chromosome number (2n = 4x = 132). Further analysis of the high-quality genomes shed lights on the genomic basis of involutional reproduction, allomones biosynthesis and adaptive evolution in Chinese pepper, revealing a high consistent relationship between genomic evolution, environmental factors and phenotypic innovation. Our study provides genomic resources and new insights for investigating diversification and phenotypic innovation in Chinese pepper, with broader implications for the protection of plants under severe environmental changes. 相似文献
97.
The endoplasmic reticulum (ER) membrane protein complex (EMC) is essential for the insertion of a wide variety of transmembrane proteins into the plasma membrane across cell types. Each EMC is composed of Emc1-7, Emc10, and either Emc8 or Emc9. Recent human genetics studies have implicated variants in EMC genes as the basis for a group of human congenital diseases. The patient phenotypes are varied but appear to affect a subset of tissues more prominently than others. Namely, craniofacial development seems to be commonly affected. We previously developed an array of assays in Xenopus tropicalis to assess the effects of emc1 depletion on the neural crest, craniofacial cartilage, and neuromuscular function. We sought to extend this approach to additional EMC components identified in patients with congenital malformations. Through this approach, we determine that EMC9 and EMC10 are important for neural crest development and the development of craniofacial structures. The phenotypes observed in patients and our Xenopus model phenotypes similar to EMC1 loss of function likely due to a similar mechanism of dysfunction in transmembrane protein topogenesis. 相似文献
98.
Jonathan Lightner Gregory Pearce Clarence A. Ryan John Browse 《Molecular genetics and genomics : MGG》1993,241(5-6):595-601
As a first step towards developing a genetic system for investigating signaling processes in plants, we have developed a screen for signaling mutants deficient in a wound response. We have isolated two mutants of tomato that lack detectable production of proteinase inhibitors induced systemically in leaves by wounding. The mutants are deficient in the induction of both proteinase Inhibitor I and proteinase Inhibitor II but can be induced to respond at near wild-type levels by methyl jasmonate, a known elicitor of inhibitor production in tomato. While completely deficient in systemic production of proteinase inhibitors, both mutants produce some proteinase inhibitor in wounded leaves. This evidence suggests the existence of two signaling pathways, one local and one systemic, that regulate the induction of proteinase inhibitor snythesis in response to wounding. 相似文献
99.
100.
A rapid method for extraction of cotton (Gossypium spp.) genomic DNA suitable for RFLP or PCR analysis 总被引:13,自引:0,他引:13
Andrew H. Paterson Curt L. Brubaker Jonathan F. Wendel 《Plant Molecular Biology Reporter》1993,11(2):122-127
Extraction of high-quality genomic DNA fromGossypium (cotton) species is difficult due to high levels of polysaccharide, oxidizable quinones, and other interfering substances.
We describe a procedure that consistently permits isolation of cotton genomic DNA of satisfactory size and quality for RFLP
and PCR analysis, as well as for most routine cloning applications. Several antioxidants, phenol-binding reagents, and phenol
oxidase inhibitors are used throughout the procedure, and most polysaccharides are eliminated early in the procedure by isolation
of nuclei. 相似文献