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排序方式: 共有792条查询结果,搜索用时 15 毫秒
101.
102.
Girón ME Salazar AM Aguilar I Pérez JC Sánchez EE Arocha-Piñango CL Rodríguez-Acosta A Guerrero B 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2008,147(1):113-121
Bothrops colombiensis venom from two similar geographical locations were tested for their hemostatic functions and characterized by gel-filtration chromatography and SDS-PAGE electrophoresis. The snakes were from Caucagua and El Guapo towns of the Venezuelan state of Miranda. Fibrino(geno)lytic, procoagulant, hemorrhagic, lethal activities, gel-filtration chromatography and SDS-PAGE profiles were analyzed and compared for both venoms. The highest hemorrhagic activity of 5.3 mug was seen in El Guapo venom while Caucagua venom had the lowest LD(50) of 5.8 mg/kg. Both venoms presented similar thrombin-like activity. El Guapo showed a factor Xa-like activity two times higher than Caucagua. Differences were observed in kallikrein-like and t-PA activities, being highest in El Guapo. Caucagua venom showed the maximum fibrin lysis. Both crude venom runs on Sephadex G-100 chromatography gave fraction SII with the high fibrinolytic activity. Proteases presented in SII fractions and eluted from Benzamidine-Sepharose (not bound to the column) provoked a fast degradation of fibrinogen alpha chains and a slower degradation of beta chains, which could possibly be due to a higher content of alpha fibrinogenases in these venoms. The fibrinogenolytic activity was decreased by metalloprotease inhibitors. The results suggested that metalloproteases in SII fractions were responsible for the fibrinolytic activity. The analysis of samples for fibrin-zymography of SII fractions showed an active band with a molecular mass of approximately 30 kDa. These results reiterate the importance of using pools of venoms for antivenom immunization, to facilitate the neutralization of the maximum potential number of toxins. 相似文献
103.
Trichomycterus chungaraensis is an endemic and endangered fish from the south high Andean plateau; mainly due to its habitat total extension thus has
been calculated to be 2,910 m2 and inhabiting solely in Mal Paso stream, at the UNESCO Biosphere Reserve and Lauca National Park. 相似文献
104.
Placenta defects and embryonic lethality resulting from disruption of mouse hydroxysteroid (17-beta) dehydrogenase 2 gene 总被引:1,自引:0,他引:1
Rantakari P Strauss L Kiviranta R Lagerbohm H Paviala J Holopainen I Vainio S Pakarinen P Poutanen M 《Molecular endocrinology (Baltimore, Md.)》2008,22(3):665-675
Hydroxysteroid (17-beta) dehydrogenase 2 (HSD17B2) is a member of aldo-keto reductase superfamily, known to catalyze the inactivation of 17beta-hydroxysteroids to less active 17-keto forms and catalyze the conversion of 20alpha-hydroxyprogesterone to progesterone in vitro. To examine the role of HSD17B2 in vivo, we generated mice deficient in Hsd17b2 [HSD17B2 knockout (KO)] by a targeted gene disruption in embryonic stem cells. From the homozygous mice carrying the disrupted Hsd17b2, 70% showed embryonic lethality appearing at the age of embryonic d 11.5 onward. The embryonic lethality was associated with reduced placental size measured at embryonic d 17.5. The HSD17B2KO mice placentas presented with structural abnormalities in all three major layers: the decidua, spongiotrophoblast, and labyrinth. Most notable was the disruption of the spongiotrophoblast and labyrinthine layers, together with liquid-filled cysts in the junctional region and the basal layer. Treatments with an antiestrogen or progesterone did not rescue the embryonic lethality or the placenta defect in the homozygous mice. In hybrid background used, 24% of HSD17B2KO mice survived through the fetal period but were born growth retarded and displayed a phenotype in the brain with enlargement of ventricles, abnormal laminar organization, and increased cellular density in the cortex. Furthermore, the HSD17B2KO mice had unilateral renal degeneration, the affected kidney frequently appearing as a fluid-filled sac. Our results provide evidence for a role for HSD17B2 enzyme in the cellular organization of the mouse placenta. 相似文献
105.
The ultrastructure of a new microsporidian, Pankovaia semitubulata gen. et sp. n. (Microsporidia: Tuzetiidae), from the fat body of Cloeon dipterum (L.) (Ephemeroptera: Baetidae) is described. The species is monokaryotic throughout the life cycle, developing in direct contact with the host cell cytoplasm. Sporogonial plasmodium divides into 2-8 sporoblasts. Each sporoblast, then spore, is enclosed in an individual sporophorous vesicle. Fixed and stained spores of the type species P. semitubulata are 3.4 x 1.9microm in size. The polaroplast is bipartite (lamellar and vesicular). The polar filament is isofilar, possessing 6 coils in one row. The following features distinguish the genus Pankovaia from other monokaryotic genera of Tuzetiidae: (a) exospore is composed of multiple irregularly laid tubules with a lengthwise opening, referred to as "semitubules"; (b) episporontal space of sporophorous vesicle (SPV) is devoid of secretory formations; (c) SPV envelope is represented by a thin fragile membrane. 相似文献
106.
107.
Artistic creativity forms the basis of music culture and music industry. Composing, improvising and arranging music are complex creative functions of the human brain, which biological value remains unknown. We hypothesized that practicing music is social communication that needs musical aptitude and even creativity in music. In order to understand the neurobiological basis of music in human evolution and communication we analyzed polymorphisms of the arginine vasopressin receptor 1A (AVPR1A), serotonin transporter (SLC6A4), catecol-O-methyltranferase (COMT), dopamin receptor D2 (DRD2) and tyrosine hydroxylase 1 (TPH1), genes associated with social bonding and cognitive functions in 19 Finnish families (n = 343 members) with professional musicians and/or active amateurs. All family members were tested for musical aptitude using the auditory structuring ability test (Karma Music test; KMT) and Carl Seashores tests for pitch (SP) and for time (ST). Data on creativity in music (composing, improvising and/or arranging music) was surveyed using a web-based questionnaire. Here we show for the first time that creative functions in music have a strong genetic component (h2 = .84; composing h2 = .40; arranging h2 = .46; improvising h2 = .62) in Finnish multigenerational families. We also show that high music test scores are significantly associated with creative functions in music (p<.0001). We discovered an overall haplotype association with AVPR1A gene (markers RS1 and RS3) and KMT (p = 0.0008; corrected p = 0.00002), SP (p = 0.0261; corrected p = 0.0072) and combined music test scores (COMB) (p = 0.0056; corrected p = 0.0006). AVPR1A haplotype AVR+RS1 further suggested a positive association with ST (p = 0.0038; corrected p = 0.00184) and COMB (p = 0.0083; corrected p = 0.0040) using haplotype-based association test HBAT. The results suggest that the neurobiology of music perception and production is likely to be related to the pathways affecting intrinsic attachment behavior. 相似文献
108.
Many processes in a cell depend on protein–protein interactions (PPIs) and perturbations of these interactions can lead to diseases. Comprehensive knowledge of PPI networks will not only give us information on how the cell is organized, but will also provide new drug targets. Current binary PPI networks are mainly generated by high-throughput yeast two-hybrid. Due to the small overlap of these maps, it has long been assumed that these maps are of low quality containing many false positives. However, by using an orthogonal two-hybrid method, MAPPIT (mammalian protein–protein interaction trap), these maps were shown to be of high quality suggesting that the limited overlap is likely due to low sensitivity and not to low specificity. 相似文献
109.
Aranzamendi C Tefsen B Jansen M Chiumiento L Bruschi F Kortbeek T Smith DF Cummings RD Pinelli E Van Die I 《Experimental parasitology》2011,129(3):221-226
Diagnostic methods for parasite infections still highly depend on the identification of the parasites by direct methods such as microscopic examination of blood, stool and tissue biopsies. Serodiagnosis is often carried out to complement the direct methods; however, few synthetic antigens with sufficient sensitivity and specificity are available. Here we evaluated a glycan microarray approach to select for synthetic glycan antigens that could be used for serodiagnosis of parasitic infections. Using a glycan array containing over 250 different glycan antigens, we identified GalNAcβ1–4(Fucα1–3)GlcNAc-R (LDNF) as a glycan antigen that is recognized by antibodies from Trichinella-infected individuals. We synthesized a neoglycoconjugate, consisting of five LDNF molecules covalently coupled to bovine serum albumin (BSA), and used this neoglycoconjugate as an antigen to develop a highly sensitive total-Ig ELISA for serological screening of trichinellosis. The results indicate that glycan microarrays constitute a promising technology for fast and specific identification of parasite glycan antigens to improve serodiagnosis of different parasitic infections, either using an ELISA format, or parasite-specific glycan arrays. 相似文献
110.
Cruz A Xicohtencatl-Cortes J González-Pedrajo B Bobadilla M Eslava C Rosas I 《Canadian journal of microbiology》2011,57(9):735-744
Cronobacter spp. ( Enterobacter sakazakii ) includes gram-negative opportunistic foodborne pathogens known as rare but important causes of life-threatening neonatal infections. However, the pathogenic mechanism is not yet clear. In this study, 43 isolates of Cronobacter, from human and nonhuman sources, were analyzed. A total of four clusters were identified and 32 DNA pulsotypes were observed by pulsed-field gel electrophoresis. In addition, 86% of the Cronobacter isolates were able to adhere to HEp-2 cells and 35% were invasive, Cronobacter sakazakii isolates being the most efficient. Twenty-six percent of Cronobacter isolates were able to form biofilms, mainly those from nonhuman sources, such as Cronobacter dublinensis and Cronobacter malonaticus . Three putative virulence genes (siderophore-interacting protein (sip), type III hemolysin (hly), and plasminogen activator (cpa)) were identified by bioinformatic analysis and then detected by PCR. The sip gene was the most frequently detected (60%; 26/43), followed by the hly gene (37%; 16/43) and the cpa gene (28%; 12/43). The three genes were identified primarily in C. sakazakii. Our data show that Cronobacter species harbor different virulence traits. 相似文献