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1.
2.
Background
Spidroins are a unique family of large, structural proteins that make up the bulk of spider silk fibers. Due to the highly variable nature of their repetitive sequences, spidroin evolutionary relationships have principally been determined from their non-repetitive carboxy (C)-terminal domains, though they offer limited character data. The few known spidroin amino (N)-terminal domains have been difficult to obtain, but potentially contain critical phylogenetic information for reconstructing the diversification of spider silks. Here we used silk gland expression data (ESTs) from highly divergent species to evaluate the functional significance and phylogenetic utility of spidroin N-terminal domains. 相似文献3.
A simple method is described for picomole determinations of fatty acid metal salts. Fatty acid salts are directly labeled with 4-bromomethyl-7-methoxycoumarin in the presence of excess ethylenediaminetetraacetic acid tripotassium salt without any solvent extractions. The fluorescence derivatives of fatty acids are separated by reverse-phase high-performance liquid chromatography followed by fluorometric detection. The response of each fatty acid (C8-C18) calcium salt is linear from 1 to 50 micrograms/ml of samples. The detection limit is about 7 pmol. Good recoveries are obtained for the calcium salts of myrystic acid and soap (C8-C18, C18:1,2). The new method is successfully applied to the study on biodegradation of fatty acids in river water. 相似文献
4.
Ruxandra Ion L. Telvi Jean-Louis Chaussain Jacques Patrick Barbet Manoel Nunes Anne Safar Marie-Odile Réthoré Marc Fellous Ken McElreavey 《Human genetics》1998,102(2):151-156
In 46,XY individuals, testes are determined by the activity of the SRY gene (sex-determining region Y), located on the short arm of the Ychromosome. The other genetic components of the cascade
that leads to testis formation are unknown and may be located on the Xchromosome or on the autosomes. Evidence for the existence
of several loci associated with failure of male sexual development is indicated by reports of 46,XY gonadal dysgenesis associated
with structural abnormalities of the Xchromosome or of autosomes (chromosomes9, 10, 11 and 17). In this report, we describe
the investigation of a child presenting with multiple congenital abnormalities, mental retardation and partial testicular
failure. The patient had a homogeneous de novo 46,XY,inv dup(9)(pter→p24.1::p21.1 →p23.3::p24.1→qter) chromosome complement.
No deletion was found by either cytogenetic or molecular analysis. The SRY gene and DSS region showed no abnormalities. Southern blotting dosage analysis with 9p probes and fluorescent in situ hybridisation data
indicated that the distal breakpoint of the duplicated fragment was located at 9p24.1, proximal to the SNF2 gene. We therefore suggest that a gene involved in normal testicular development and/or maintenance is present at this position
on chromosome 9.
Received: 20 January 1997 / Accepted: 5 November 1997 相似文献
5.
6.
7.
Changes in Targeting Efficiencies of Proteins to Plant Microbodies Caused by Amino Acid Substitutions in the Carboxy-terminal Tripeptide 总被引:7,自引:0,他引:7
Hayashi Makoto; Aoki Masahiro; Kondo Maki; Nishimura Mikio 《Plant & cell physiology》1997,38(6):759-768
It has been demonstrated that the carboxyl terminus of microbodyenzymes functions as a targeting signal to microbodies in higherplants. We have examined an ability of 24 carboxy-terminal aminoacid sequences to facilitate the transport of a cytosolic passengerprotein, ß-glucuroni-dase, into microbodies in greencotyledonary cells of trans-genic Arabidopsis. Immunoelectronmicroscopic analysis revealed that carboxy-terminal tripeptidesequences of the form [C/A/S/P]-[K/R]-[I/L/M] function as amicrobody-targeting signal, although tripeptides with prolineat the first amino acid position and isoleucine at the carboxylterminus show weak targeting efficiencies. All known micro-bodyenzymes that are synthesized in a form similar in size to themature molecule, except catalase, contain one of these tripeptidesequences at their carboxyl terminus. (Received April 14, 1997; Accepted April 8, 1997) 相似文献
8.
Ken Muneoka 《Developmental biology》1980,74(2):486-489
Pasteur pipets were prepared with constricted tips of such diameter that unfertilized Ciona intestinalis (L.) eggs could be held immobile while their chorions were lanced open with a tungsten needle. Eggs were pretreated with double-strength seawater to increase the space between egg and chorion. Eighty-five percent of the eggs dechorionated in this way developed normally after fertilization in regular seawater. 相似文献
9.
M Honda T Yoshimura T Watanabe H Hayashi 《Journal of immunology (Baltimore, Md. : 1950)》1983,131(6):2989-2994
The chemotactic specificity of ia-positive and -negative macrophages was studied by using three macrophage chemotactic factors (MCF), -a, -b, and -c, isolated from delayed hypersensitivity reaction (DHR) skin sites in guinea pigs. Listeria-elicited macrophages migrated toward MCF-a, -b, and -c. The chemotactic responses suggested responsive subpopulations to MCF. The electronic programmable individual cell sorter (EPICS) was used to separate macrophages with anti-la monoclonal antibodies. Ia-positive subpopulations responded to MCF-c, although they did not migrate toward MCF-a and -b. In contrast, Ia-negative subpopulations migrated toward MCF-a and -b, but not toward MCF-c. Furthermore, MCF-c attracted Ia-positive macrophages, whereas MCF-a and -b were Ia-negative in vitro; MCF did not induce Ia-negative macrophages to express surface Ia-antigens in vitro. MCF-c was able to produce massive Ia-positive macrophage accumulations when injected i.p., whereas MCF-a accumulated Ia-negative macrophages. The data suggest that MCF-a and -b, which mediate initial macrophage reactions, attract Ia-negative macrophages, and that MCF-c, which mediates predominant macrophage reactions, attract Ia-positive macrophages in the DHR. 相似文献