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RENATO A. MORTARA 《The Journal of eukaryotic microbiology》1989,36(1):8-13
In this study, the presence of actin in cultured trypanosomatids was investigated using polyclonal antibodies to heterologous actin. Polyclonal antisera to rabbit muscle actin and a monospecific anti-actin antibody react with a 43-kDa polypeptide in extracts of Trypanosoma cruzi, Herpetomonas samuelpessoai and Leishmania mexicana amazonensis on protein immunoblots. The 43-kDa polypeptide co-migrates with skeletal muscle actin and is retained within trypanosomatid cytoskeletons. Attempts to isolate H. samuelpessoai actin through DNase I affinity chromatography showed that the 43-kDa polypeptide did not bind to the column. Instead, low yields of a 47-kDa polypeptide were obtained indicating that the trypanosomatid actin displays unusual DNase I binding behavior when compared to actins from higher eukaryotes. Immunofluorescence studies confirmed that cytoskeletons retain the actin-like protein. In H. samuelpessoai , actin is localized in the region close to the flagellum, whereas in T. cruzi it is more homogeneously distributed. The data presented here show that trypanosomatid actin displays biochemical characteristics similar to actins of other protozoa. 相似文献
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VITALE ALESSANDRO; SMANIOTTO ELISA; LONGHI RENATO; GALANTE ENNIO 《Journal of experimental botany》1982,33(3):439-448
Endosperm protein bodies from developing maize were purifiedby discontinuous sucrose gradient centrifugation and the proteincontent analysed by sodium dodecyl sulphate polyacrylamide gelelectrophoresis (SDS-PAE). Major proteins detected were zeinpolypeptides plus a component with Mr 28 000 and a doublet aroundMr 58 000. These proteins were present only in the protein bodyfraction of the sucrose gradient. Treatment of protein bodieswith the reducing agent dithiothreitol (DTT) in aqueous bufferdissolved the components with Mr 28 000 and 58 000, plus minorones, but not zein. The reduced soluble proteins were separatedby DEAE-Sephacel chromatography into three fractions: two ofthese contained the component with Mr 28 000, and the thirdthe components around Mr 58 000 plus minor ones. Proteins fromthe three fractions had characteristic amino acid compositions,markedly different from those of zein polypeptides. Chymotrypticdigestion experiments performed on protein bodies under variousconditions, and two-dimensional electrophoresis of proteinsfrom protein bodies suggested that the major zein polypeptides,the protein with Mr 28 000 and the other reduced soluble proteinshave different native organizations. 相似文献
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ANDREA DE OLIVEIRA RIBEIRO JUNQUEIRA CARLOS RENATO REZENDE VENTURA ADRIANA LUIZA P.S. DE CARVALHO ANDERS JENSEN SCHMIDT 《Invertebrate reproduction & development.》2013,57(1-3):143-150
Summary The size, structure, and density of a population of Lytechinus variegatus were recorded from a shallow seagrass bed (Halodule wrightii) at 40-day intervals from April 1994 to April 1995. A local mass mortality was observed in May 1994. The density declined from 0.57±0.10 to 0.06±0.05 ind.m?2, mean size declined from 37.6±0.49 to 16.2±2.14 mm and maximum size from 75 to 40 mm. Ten months after mortality, the maximum and mean sizes had returned to initialvalues, but density had not (0.10±0.03 ind.m?2). A second, smaller mass mortality occurred in April 1995. High values of gonad index were recorded before mortality (9.40±5.97) and after population recovery (11.96±5.74). Recruitment was continuous throughout the year, but reached a peak from August to October. This can he related to the patterns of upwelling in the region. Mass mortality is probably an annual event in this population that can be correlated with the occurrence of low tides during daytime in the fell. The population can recover during the summer when low tides occur during the night. The massive input of recruits prevents extinction of the population during the season of high mortality. Population recovery depends on the magnitude of recruitment. 相似文献
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PATRICIA FERNANDES NERES VERÔNICA GOMES DA FONSECA‐GENEVOIS RODRIGO AUGUSTO TORRES MARIANA DA FONSECA CAVALCANTI FRANCISCO JOSÉ VICTOR DE CASTRO NEYVAN RENATO RODRIGUES DA SILVA TANIA TASSINARI RIEGER WILFRIDA DECRAEMER 《Zoological Journal of the Linnean Society》2010,158(1):1-15
A new species of Daptonema is described based upon morphological characters and 18S rRNA sequence. Daptonema matrona sp. nov. was collected in Pina Basin (north‐eastern Brazil). It differs from all other species of the genus by the presence of reduced cephalic setae and straight spicules. These features require an adaptation of the generic diagnosis. Moreover, the females are characterized by intra‐uterine development of the offspring, considered herein as their major autapomorphic feature. Molecular systematic analyses supported Daptonema matrona sp. nov. as a distinct genetic and evolutionary lineage. The data also indicate hypotheses of taxonomic synonymies amongst some related taxa from Xyalidae as well as the paraphyly of Daptonema. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 1–15. 相似文献
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JESÚS E. MALDONADO JENNIFER LEONARD GUSTAVO A. MIRANDA JORGE ORTEGA ROBERT K. WAYNE RENATO J. AGUILERA 《Molecular ecology resources》2006,6(2):349-352
The ornate shrew (Sorex ornatus) is restricted to the vanishing wetlands of California, USA and Baja California, Mexico. Several subspecies of ornate shrews are considered ‘mammal species of special concern’ in California by the Department of Fish and Game, and one (Sorex ornatus relictus) has recently been listed as endangered. Populations of shrews around Buena Vista Lake have been diminished or extirpated due to habitat deterioration and human development. In order to study the patterns of genetic variation in isolated populations of Buena Vista Lake shrews, we developed 10 polymorphic microsatellite loci. There were 6–27 alleles per locus, and the loci had heterozygosity values that ranged from 20 to 80%. In addition, we screened 20 different populations of S. ornatus, eight species within two subfamilies of shrews (Soricinae and Crocidurinae), as well as in a mole (Talpidae, Neurotrichus gibbsii), to determine if these loci could be informative in other species as well. 相似文献
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Ubiquity of Cysteine- and Metalloproteinase Activities in a Wide Range of Trypanosomatids 总被引:1,自引:0,他引:1
MARTA H. BRANQUINHA ALANE B. VERMELHO SAMUEL GOLDENBERG MYRNA C. BONALDO 《The Journal of eukaryotic microbiology》1996,43(2):131-135
We have analysed the proteinase profiles of 11 species from 7 different genera of trypanosomatids by in situ detection of enzyme activities on SDS-PAGE gels containing co-polymerized gelatin as substrate, and the use of specific proteinase inhibitors. Our survey indicates that while cysteine- and metalloproteinases are distributed ubiquitously among trypanosomatids, there are marked differences between the enzyme profiles from the monogenetic (Crithidia, Herpetomonas, Leptomonas) and digenetic (Trypanosoma, Endotrypanum, Phytomonas, Leishmania) species. The detected metalloproteinase activities, ranging in size from 50–100 kDa, partitioned into the detergent-phase after Triton X-114 extraction, while most of cysteine proteinases, of three distinct molecular mass ranges (30–50 kDa, 80–100 kDa and 116–205 kDa), partitioned into the aqueous phase. Thus, within this group of organisms, the metalloproteinase activities seem to be predominantly membrane-associated proteins. We also show that the plant parasites of the genus Phytomonas exhibit a distinctive cysteine proteinase profile that might be exploited further as a criterion for taxonomy of the genus. 相似文献
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WHEN the replication of density-inhibited cultures of fibroblasts1,2 is stimulated by a change of medium3–5, the rate of nuclear acidic protein synthesis10–13 is immediately increased. We wanted to determine whether the induction of cellular DNA synthesis by an oncogenic virus6–9 is also preceded by nuclear acidic protein synthesis. We report here the effect of SV40 virus infection of a permissive and a non-permissive cell line on their synthesis of total cellular proteins and nuclear acidic proteins in the first hours after infection. 相似文献
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One of the more striking morphological events during egg activation is exocytosis of the cortical granules. In the frog egg, the wave of cortical granule exocytosis takes about 100 sec to traverse the animal half, and travels slower in the vegetal half. We examined cortical granule exoctyosis during activation with respect to this animal/vegetal difference. In eggs which were acquiring the ability to be activated (recovering from CO2-intoxication or undergoing meiotic maturation), animal half cortical granules became capable of responding to activating stimuli prior to vegetal half ones. Since Ca2+ is involved in exocytosis, we examined the effect of Ca2+ on cortical granule breakdown in vitro. There was no difference in sensitivity to Ca2+ of cortical granules from immature vs. mature eggs, but animal half cortical granules were more sensistive to Ca2+ than vegetal half ones. Finally, we found that prick-activation of eggs at the vegetal pole was frequently unsuccessful but would occur when external Ca2+ was raised. These experiments show that there are regional differences in the frog egg with respect to cortical granule responsiveness, and they suggest that the differences are due to Ca2+ sensitivity. 相似文献