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121.
Diana Sarno Wiebe H. C. F. Kooistra Sergio Balzano Paul E. Hargraves Adriana Zingone 《Journal of phycology》2007,43(1):156-170
Skeletonema costatum (Grev.) Cleve emend. Zingone et Sarno and S. grevillei Sarno et Zingone were known only from the type material collected from Hong Kong waters more than a century ago. Both species have now been collected as live material, and their morphology and phylogenetic position are investigated in this study. Eight Skeletonema strains isolated from Florida, USA; Uruguay; and Brazil are attributed to S. costatum, while one strain from Oman is ascribed to S. grevillei based on morphological similarity to the type material of these species. In addition, a new Skeletonema species, S. ardens Sarno et Zingone, is described for a strain from Singapore and two from northern Australian waters. Skeletonema ardens has terminal fultoportula processes ending in a tapered, undulate protrusion and long intercalary fultoportulae with 1:1 junctions. The rimoportula of terminal valves is located at the margin of the valve face. No major morphological variations were observed within S. grevillei and S. ardens along a salinity gradient, whereas in S. costatum, the processes shortened and the valves came into close contact at low salinities, as already described for S. subsalsum (Cleve) Bethge. Consistent with their morphology, Skeletonema costatum and Skeletonema subsalsum also had similar rDNA sequences. Skeletonema grevillei and S. ardens were distinct in the large subunit (LSU) phylogeny. Skeletonema ardens exhibited consistent intraspecific genetic differences in both the LSU and small subunit (SSU) rDNA. 相似文献
122.
Lima RF Santos Brito MM Schäffer GM Lima OC Borba Cde M 《Canadian journal of microbiology》2004,50(6):445-449
Morphological differentiation has commanded attention for its putative impact on the pathogenesis of invasive fungal infections. We evaluated in vitro and in vivo the dimorphism from mycelial to yeast-phase of Sporothrix schenckii, Blastomyces dermatitidis and Paracoccidioides brasiliensis isolates, two strains for each species, preserved in mineral oil. S. schenckii strains showed typical micromorphology at 25 degrees C but one strain was unable to complete the dimorphic process in vitro. After in vivo passage through mice the strains had the ability to turn into yeast-like cells and to form colonies on brain-heart infusion medium at 36 degrees C. B. dermatitidis strains grew as dirty white to brownish membranous colonies at 25 degrees C and their micromorphology showed thin filaments with single hyaline conidia. At 36 degrees C the colonies did not differ from those grown at 25 degrees C, but produced a transitional micromorphology. P. brasiliensis strains grew as cream-colored cerebriform colonies at 25 degrees C showing a transitional morphology. B. dermatitidis and P. brasiliensis strains did not turn into yeast-like cells in vivo. The present results demonstrate that B. dermatitidis and P. brasiliensis strains were unable to complete the dimorphic process even after in vivo passage, in contrast to the S. schenckii strain. 相似文献
123.
De Moliner E Moro S Sarno S Zagotto G Zanotti G Pinna LA Battistutta R 《The Journal of biological chemistry》2003,278(3):1831-1836
Protein kinases play key roles in signal transduction and therefore are among the most attractive targets for drug design. The pharmacological aptitude of protein kinase inhibitors is highlighted by the observation that various diseases with special reference to cancer are because of the abnormal expression/activity of individual kinases. The resolution of the three-dimensional structure of the target kinase in complex with inhibitors is often the starting point for the rational design of this kind of drugs, some of which are already in advanced clinical trial or even in clinical practice. Here we present and discuss three new crystal structures of ATP site-directed inhibitors in complex with "casein kinase-2" (CK2), a constitutively active protein kinase implicated in a variety of cellular functions and misfunctions. With the help of theoretical calculations, we disclose some key features underlying the inhibitory efficiency of anthraquinone derivatives, outlining three different binding modes into the active site. In particular, we show that a nitro group in a hydroxyanthraquinone scaffold decreases the inhibitory constants K(i) because of electron-withdrawing and resonance effects that enhance the polarization of hydroxylic substituents in paraposition. 相似文献
124.
Kinetics of T cell-activation molecules in response to Mycobacterium tuberculosis antigens 总被引:3,自引:0,他引:3
Antas PR Oliveira EB Milagres AS Franken KC Ottenhoff TH Klatser P Sarno EN Sampaio EP 《Memórias do Instituto Oswaldo Cruz》2002,97(8):1097-1099
The phenotypic features acquired subsequent to antigen-specific stimulation in vitro were evaluated by means of the kinetic expressions of CD69 and CD25 activation molecules on T lymphocytes and assayed by flow cytometry in response to PPD, Ag85B, and ferritin in PPD-positive healthy control individuals. In response to PHA, CD69 staining on both CD4+ and CD8+ T cells became initially marked after 4 h, peaked at 24 h, and quickly decreased after 120 h. For CD25, a latter expression was detected around 8 h, having increased after 96 h. As expected, the response rate to the mycobacterial antigens was much lower than that to the mitogen. Positive staining was high after 96 h for CD25 and after 24 h for CD69. CD69 expression was significantly enhanced (p < 0.05) on CD8+ as compared to CD4+ T cells. High levels were also found between 96-120 h. Regarding Ag85B, CD25+ cells were mostly CD4+ instead of CD8+ T cells. Moreover, in response to ferritin, a lower CD25 expression was noted. The present data will allow further characterization of the immune response to new mycobacterial-specific antigens and their evaluation for possible inclusion in developing new diagnostic techniques for tuberculosis as well in a new vaccine to prevent the disease. 相似文献
125.
Claudia S. Mermelstein Fatima C. Guma Tanira G. Mello Vitor A. Fortuna Regina M. Guaragna Manoel L. Costa Radovan Borojevic 《Cell and tissue research》2001,306(1):75-83
Hepatic stellate cells (HSCs) are intralobular connective tissue cells presenting myofibroblast or lipocyte phenotypes. They participate in the homeostasis of liver extracellular matrix, repair, regeneration and fibrosis under the former phenotype, and control retinol metabolism, storage and release under the latter one. Responding to systemic or local demands, they can convert into the required phenotype with deep modifications of their structures. Using immunofluorescence microscopy and Western blots, we investigated the expression and organisation of actin filaments and of two actin-binding proteins, alpha-actinin and tropomyosin, in the cloned GRX cell line representative of murine HSCs. GRX cells expressing the myofibroblast phenotype showed typical well-organised actin stress-fibres, anchored at the focal adhesions located at the cell periphery. Retinol treatment induced active reorganisation of the cytoskeleton. The major stress fibres were reduced in length, and frequently formed a polygonal meshwork. Subsequently, they fragmented and generated diffuse or granular actin in the perinuclear area, a thin continuous layer around lipid droplets and, in fully converted lipocytes, a peripheral layer of thin actin fibres. alpha-Actinin and tropomyosin were present only in lipocytes, co-distributed with actin in a granular form. Since the cytoskeleton reorganisation preceded lipid accumulation, we conclude that the induction of the lipocyte phenotype represents a full reprogramming of cell gene expression and function. We consider that both the lipocyte and the myofibroblast phenotypes should be considered "activated states" of HSCs, each responding to specific physiological or pathological modifications of liver functions. 相似文献
126.
127.
A multifunctional network of basic residues confers unique properties to protein kinase CK2 总被引:4,自引:0,他引:4
Protein kinase CK2 is characterized by a number of features, including substrate specificity, inhibition by polyanionic compounds and intrasteric down-regulation by its -subunit, which denote a special aptitude to interact with negatively charged ligands. This situation may reflect the presence in CK2 catalytic subunits of several basic residues that are not conserved in the majority of other protein kinases. Some of these residues, notably K49 in the Gly rich loop, K74, K75, K76, K77, K79, R80, K83 in the Lys rich segment and R191, R195, K198 in the p+1 loop, have been shown by mutational studies to be implicated to various extents and with distinct roles in substrate recognition, inhibition by heparin and by pseudosubstrate and instrasteric regulation. Molecular modelization based on crystallographic data provide a rationale for the biochemical observations, showing that several of these basic residues are clustered around the active site where they make contact with individual acidic residues of the peptide substrate. They can also mediate the effect of polyanionic inhibitors (e.g. heparin) and of regulatory elements present in the b-subunit, in the N terminal segment of the catalytic subunit and possibly in other proteins interacting with CK2. Our data also disclose a unique mode of binding of the phosphoacceptor substrate which bridges across the catalytic cleft making contacts with both the lower and upper lobes of CK2. 相似文献
128.
Elthon G. Ferreira Diego V. Wilke Paula C. Jimenez Julieta R. de Oliveira Otília Deusdênia L. Pessoa Edilberto R. Silveira Francisco A. Viana Cláudia Pessoa Manoel Odorico de Moraes Eduardo Hajdu Letícia Veras Costa‐Lotufo 《化学与生物多样性》2011,8(8):1433-1445
Five guanidine alkaloids, mirabilin B ( 1 ), 8bβ‐hydroxyptilocaulin ( 2 ), ptilocaulin ( 3 ), and a mixture of the 8β‐ and 8α‐epimers, 4 and 5 , of 8‐hydroxymirabilin (1,8a;8b,3a‐didehydro‐8‐hydroxyptilocaulin), were isolated from Monanchora arbuscula colonies collected off the northeastern Brazilian coast. All structures were elucidated by spectroscopic analysis, including 1D (1H‐, 13C‐ (BB), and 13C‐DEPT) and 2D (COSY, HSQC, and HMBC) NMR experiments, and comparison with the literature data. The cytotoxicity of the isolated compounds were evaluated against four tumor cell lines, showing that mirabilin B ( 1 ) and the two epimers were inactive, while 8bβ‐hydroxyptilocaulin ( 2 ) and ptilocaulin ( 3 ) presented IC50 values in the range of 7.9 to 61.5 μM , and 5.8 to 40.0 μM , respectively. Further studies on the mechanism of action of ptilocaulin, using HL‐60 leukemia cells, demonstrated that this guanidine compound induced apoptosis of the treated cells. 相似文献
129.
Influences of FSH and EGF on primordial follicles during in vitro culture of caprine ovarian cortical tissue 总被引:2,自引:0,他引:2
Silva JR van den Hurk R de Matos MH dos Santos RR Pessoa C de Moraes MO de Figueiredo JR 《Theriogenology》2004,61(9):1691-1704
Factors that control the onset of folliculogenesis are critical to female gamete production, but poorly understood. The aim of the present study was to investigate the effects of FSH and EGF on the activation and growth of goat primordial follicles in vitro. To this end, pieces of goat ovarian cortex were cultured in vitro for 1, 3 or 5 days, at 39 degrees C in an atmosphere containing 5% CO(2), in minimum essential medium supplemented with insulin, transferrin, selenium, pyruvate, glutamine, hypoxanthine, BSA, penicillin, streptomycin and fungizone and with or without FSH (100 ng/ml) and/or EGF (100 ng/ml). At the end of the culture periods, the relative proportions of primordial, intermediate, primary and secondary follicles were calculated and compared with those in non-cultured tissue. In addition, mitotic activity of granulosa cells was studied by immunohistochemistry for proliferating cell nuclear antigen (PCNA). In brief, it was found that goat primordial follicles activate spontaneously during culture in vitro and, while neither FSH nor EGF affected the proportion of primordial follicles that entered the growth phase, both stimulated an increase in oocyte and follicle diameter, especially in intermediate and primary follicles cultured for 5 days. On the other hand, there was no significant effect of culture or either growth factor on the proportion of PCNA-stained growing follicles. Contrary to expectations, neither FSH nor EGF affected follicle viability or integrity during culture, since the percentages of intact follicles did not differ between control, FSH and/or EGF containing medium. In conclusion, this study demonstrated that goat primordial follicles activate spontaneously in vitro, and that both FSH and EGF stimulate an increase in follicle size by promoting oocyte growth. 相似文献
130.
Nilton Ghiotti de Siqueira Cláudia Maria Villar Maziero de Siqueira Rosangela Rodrigues-Silva Manoel do Carmo P Soares Marinete Marins Póvoa 《Memórias do Instituto Oswaldo Cruz》2013,108(5):533-540
The lack of knowledge regarding polycystic hydatid disease results in
delayed or even incorrect diagnosis. The lack of systematic information
regarding treatment also makes it difficult to assess the results and prognosis
in patients with peritoneal and hepatic lesions caused by Echinococcus
vogeli. Here we describe the clinical features of patients, propose
a radiological classification protocol and describe a therapeutic option for the
treatment of hydatid disease that previously had only been used for cases of
cystic echinococcosis (Echinococcus granulosus). A prospective
cohort study was initiated in 1999 and by 2009 the study included 60 patients.
These patients were classified according to the PNM classification (parasite
lesion, neighbouring organ invasion and metastases) and placed in one of three
therapeutic modalities: (i) chemotherapy with albendazole at a dose of 10
mg/kg/day, (ii) surgical removal of cysts or (iii) percutaneous puncture of the
cysts via puncture, aspiration, injection and re-aspiration (PAIR). The results
were stratified according to therapeutic outcome: "cure", "clinical
improvement", "no improvement", "death" or "no information". The PNM
classification was useful in indicating the appropriate therapy in cases of
polycystic hydatid disease. In conclusion, surgical therapy produced the best
clinical results of all the therapies studied based on "cure" and "clinical
improvement" outcomes. The use of PAIR for treatment requires additional
study. 相似文献