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41.
Cabrero J Teruel M Carmona FD Jiménez R Camacho JP 《Cytogenetic and genome research》2007,119(1-2):135-142
The facultative heterochromatic X chromosome in leptotene spermatocytes of the grasshopper Eyprepocnemis plorans showed marked hypoacetylation for lysine 9 in the H3 histone (H3-K9) with no sign of histone H2AX phosphorylation. Since H3-K9 hypoacetylation precedes the meiotic appearance of phosphorylated H2AX (gamma-H2AX), which marks the beginning of recombinational DNA double-strand breaks (DSBs), it seems that meiotic sex-chromosome inactivation (MSCI) in this grasshopper occurs prior to the beginning of recombination and hence synapsis (which in this species begins later than recombination). In addition, all constitutively heterochromatic chromosome regions harbouring a 180-bp tandem-repeat DNA and rDNA (B chromosomes and pericentromeric regions of A chromosomes) were H3-K9 hypoacetylated at early leptotene even though they will synapse at subsequent stages. This also suggests that meiotic silencing in this grasshopper might be independent of synapsis. The H3-K9 hypoacetylated state of facultative and constitutive heterochromatin persisted during subsequent meiotic stages and was even apparent in round spermatids. Finally, the fact that B chromosomes are differentially hypoacetylated in testis and embryo interphase cells suggests that they might be silenced early in development and remain this way for most (or all) life-cycle stages. 相似文献
42.
Zanolla Marianela Carmona Raquel Mata Leonardo De la Rosa Julio Sherwood Alison Barranco Carlos Navarro Muñoz Antonio Román Altamirano María 《Journal of applied phycology》2022,34(1):1-17
Journal of Applied Phycology - Asparagopsis (Bonnemaisoniaceae, Rhodophyta) species are distributed in most temperate and tropical waters of the world, where they are considered an iconic invader.... 相似文献
43.
44.
Mayrim M. Gomes Alexandre Budu Priscilla D.S. Ventura Piero Bagnaresi Simone S. Cotrin Rodrigo L.O.R. Cunha Adriana K. Carmona Luiz Juliano Marcos L. Gazarini 《Analytical biochemistry》2015
In the intraerythrocytic trophozoite stages of Plasmodium falciparum, the calcium-dependent cysteine protease calpain (Pf-calpain) has an important role in the parasite calcium modulation and cell development. We established specific conditions to follow by confocal microscopy and spectrofluorimetry measurements the intracellular activity of Pf-calpain in live cells. The catalytic activity was measured using the fluorogenic Z-Phe-Arg-MCA (where Z is carbobenzoxy and MCA is 4-methylcoumaryl-7-amide). The calmodulin inhibitor calmidazolium and the sarcoplasmic reticulum calcium ATPase inhibitor thapsigargin were used for modifications in the cytosolic calcium concentrations that persisted in the absence of extracellular calcium. The observed calcium-dependent peptidase activity was greatly inhibited by specific cysteine protease inhibitor E-64 and by the selective calpain inhibitor ALLN (N-acetyl-l-leucyl-l-leucyl-l-norleucinal). Taken together, we observed that intracellular Pf-calpain can be selectively detected and is the main calcium-dependent protease in the intraerythrocytic stages of the parasite. The method described here can be helpful in cell metabolism studies and antimalarial drug screening. 相似文献
45.
Talita A. Sampaio e Silva Adriana Knob Célia R. Tremacoldi Marcia R. Brochetto-Braga Eleonora Cano Carmona 《World journal of microbiology & biotechnology》2011,27(11):2491-2497
Acid proteases represent an important group of enzymes, widely used in food, beverage and pharmaceutical industries. For most
of these applications the enzymatic preparation must be at least partially purified and free of substances that could change
the characteristics of the product or the process. Fungal proteases have replaced other sources because they are easily obtained
mainly from Mucor, Rhizopus, Penicillium
and
Aspergillus species. A strain of Aspergillus
clavatus was selected by producing high level of acid protease activity. An extracellular aspartatic protease from this strain was
purified 37.2 times with 37% recovery using (NH4)2SO4 fractionation and ion-exchange chromatography. The enzyme was found to be monomeric having a molecular mass of 30.4 kDa.
The purified enzyme is an acid protease with optimum pH of 5.5 and temperature for optimum activity of 50 °C. Its high pH
stability was verified in the range of 3.5–6.5. The acid protease was strongly inhibited by Hg+2 and partially inhibited by Cu+2, Zn+2 and Mn+2. The enzyme was sensitive to denaturing agent SDS and activated by thiol-containing reducing agent dithiotreitol (DTT). The
protease activity was not influenced by iodoacetic acid, E-64 and PMSF, while it was lightly actived by EDTA and totally inhibited
by pepstatin, with a Ki of 7.8 μM, indicating that is an aspartic protease. A.
clavatus acid protease presents interesting characteristics for biotechnological process, such as cheese and flavor manufacture and
dietary supplements, in which activity and stability in acid pH are required. 相似文献
46.
Puerta RC Aliz EL Lopez-Calleja MA Ramirez RR Pena GP 《Indian pacing and electrophysiology journal》2011,11(3):73-80
Background
Few studies have been performed on P wave indices in athletes. The aim of this study was to determine the behaviour of maximum P wave duration (Pmax), minimum P wave duration (Pmin) and P wave dispersion (PWD) in young high performance athletes, as well as the relationship of PWD with training history, heart rate (HR) and echocardiographic parameters.Methods
We performed a cross-sectional observational study in 38 athletes of high performance in sports: water polo, distance running and weight lifting compared with 34 sedentary controls.Results
The average age in both groups was 20.6 years. Note that PWD was increased in athletes (57 ± 14 ms vs. 40 ± 12 ms, p <0.001) while Pmin was significantly lower (57 ± 13 ms vs. 72 ± 13 ms, p <0.001), and there was no difference when comparing Pmax (114 ± 9 ms vs. 117 ± 14 ms, p> 0.05). The correlation between the duration of training (r = 0.511) and resting HR (r = 0.461) with PWD was significant (p <0.01).Conclusions
PWD is increased in young athletes of high performance and was positively correlated with duration of training and baseline HR. The increase in PWD was secondary to a significant decrease in Pmin. 相似文献47.
Carmona MC Bermúdez OG Gutiérrez-Espeleta GA Porras RS Ortiz BR 《Revista de biología tropical》2005,53(3-4):437-445
Fecal samples of 102 howler monkeys (Alouatta palliata) from several sites of Costa Rica were studied for intestinal parasites. The zones studied were: Central Valley (San Ramón, Alajuela), Central Pacific (Chomes and Manuel Antonio National Park. Puntarenas), North Pacific (Palo Verde Park and Playa Potrero, Guanacaste). Chira Island in the Nicoya Gulf and Caribean area (Cahuita. Limón). Animals were anesthetized with dards containing Telazol in order to collect the fecal material; some monkeys defecated spontaneously and others by direct stimulation. Samples were studied in saline solution (0.85%) and a Iodine solution, or stained with Haematoxylin. The material was also cultured in Dobell culture medium to determine the presence of amoeba and flagellates. Strongvloides. Controrchis. Trypanoxyuris genera were found in 3.4% of the samples. In addition 16.7% to 80% of the animals showed protozoa infection with Endolimax, Entamoeba, Trichomonas and Giardia. It is discussed the relationships of parasite infection with environmental conditions, animal population and human presence, specially in the monkey conservation programs point of view. 相似文献
48.
Puzer L Cotrin SS Cezari MH Hirata IY Juliano MA Stefe I Turk D Turk B Juliano L Carmona AK 《Biological chemistry》2005,386(11):1191-1195
The S1 and S2 subsite specificity of recombinant human cathepsins X was studied using fluorescence resonance energy transfer (FRET) peptides with the general sequences Abz-Phe-Xaa-Lys(Dnp)-OH and Abz-Xaa-Arg-Lys(Dnp)-OH, respectively (Abz=ortho-aminobenzoic acid and Dnp=2,4-dinitrophenyl; Xaa=various amino acids). Cathepsin X cleaved all substrates exclusively as a carboxymonopeptidase and exhibited broad specificity. For comparison, these peptides were also assayed with cathepsins B and L. Cathepsin L hydrolyzed the majority of them with similar or higher catalytic efficiency than cathepsin X, acting as an endopeptidase mimicking a carboxymonopeptidase (pseudo-carboxymonopeptidase). In contrast, cathepsin B exhibited poor catalytic efficiency with these substrates, acting as a carboxydipeptidase or an endopeptidase. The S1' subsite of cathepsin X was mapped with the peptide series Abz-Phe-Arg-Xaa-OH and the enzyme preferentially hydrolyzed substrates with hydrophobic residues in the P1' position. 相似文献
49.
Villapando I Ramirez M Zepeda-Rodriguez A Castro AC Cardenas-Vazquez R Vilchis F 《Journal of experimental zoology. Part A, Comparative experimental biology》2005,303(1):13-25
The Harderian glands of rodents are large intraorbital exocrine glands with histologic organization that varies among mammalian species. Here we describe some ultrastructural and biochemical features of the Harderian gland in the Mexican volcano mouse Neotomodon alstoni alstoni, a species of restricted habitat. The Harderian glands from male and female adult mice were dissected, processed and embedded in Epon 812 for light and electron microscopy studies. Porphyrin and total lipids were biochemically determined. The macroscopic appearance of the Harderian gland is similar in the male and female. The gland is a bilobulate structure, situated in the orbit towards the posterior side of the eyeball, of whitish color and is surrounded by a connective tissue capsule. The male gland is slightly heavier (127 mg) than that of the female (113 mg). The Harderian gland shows a tubulo-alveolar organization and is composed exclusively of one type of secretory cells. No branched duct system within the gland was found. Adrenergic nerves endings and mast cell were observed in the interstices of the alveoli. Male and female glands produce similar levels of porphyrins. Triglyceride levels were significantly higher (P < 0.05) in the female compared to the male. Abundance of lipids could induce corneal lubrication of the Harderian gland which may confer a protective and adaptative function to the volcano mouse in its natural habitat during the dry and cold seasons. 相似文献
50.
Cotrin SS Puzer L de Souza Judice WA Juliano L Carmona AK Juliano MA 《Analytical biochemistry》2004,335(2):244-252
We have developed positional scanning synthetic combinatorial libraries to define the substrate specificity of carboxydipeptidases. The library Abz-GXXZXK(Dnp)-OH, where Abz is ortho-aminobenzoic acid, K(Dnp) is Nε-2,4-dinitrophenyl-lysine with free carboxyl group, the Z position was successively occupied with 1 of 19 amino acids (cysteine was omitted), and X represents randomly incorporated residues, was assayed initially with human cathepsin B, and arginine was defined as one of the best residues at the P1 position. To examine the selectivity of , S2, and S3 subsites, the sublibraries Abz-GXXRZK(Dnp)-OH, Abz-GXZRXK(Dnp)-OH, and Abz-GZXRXK(Dnp)-OH were then synthesized. The peptide Abz-GIVRAK(Dnp)-OH, which contains the most favorable residues in the positions identified by screening of the libraries with cathepsin B, was hydrolyzed by this enzyme with kcat/Km = 7288 mM−1 s−1. This peptide is the most efficient substrate described for cathepsin B to this point, and it is highly selective for the enzyme among the lysosomal cysteine proteases. 相似文献