Effects of chard (Beta vulgaris L. var cicla) on the liver of the diabetic rats: a morphological and biochemical study.
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Chard (Beta vulgaris L. var cicla) is one of the medicinal herbs used by diabetics in Turkey. It has been reported to reduce blood glucose. We have investigated the effect of chard extracts on the liver by biochemical and morphological investigation. The plant extract was administered by the gavage technique to rats at a dose of 2 g/kg every d for 28 d, 14 d after experimental animals were made diabetic. In the diabetic group, some degenerative changes were observed by light and electron microscope examination, but degenerative changes decreased or were not observed in the diabetic group given chard. In the diabetic group, blood glucose levels, serum alanine, aspartate transaminase, alkaline phosphatase activities, total lipids, sialic and uric acid levels, liver lipid peroxidation (LPO), and nonenzymatic glycosylation (NEG) levels increased, while blood glutathione, body weight, and liver glutathione (GSH) levels decreased. The diabetic group given chard, serum alanine, aspartate transaminase, alkaline phosphatase activities, total lipid level, sialic and uric acid levels, blood glucose levels, and liver LPO and NEG levels decreased, but the other values increased. As a result of all the morphological and biochemical findings obtained, it was concluded that the extract of this plant has a protective effect on the liver in diabetes mellitus. (+info)
Differential localization of tonoplast intrinsic proteins on the membrane of protein body Type II and aleurone grain in rice seeds.
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Tonoplast intrinsic proteins (TIPs) belong to an aquaporin family of proteins that function as water-transport channels. In this study, we isolated and characterized three novel rice cDNAs for OsTIP1, OsTIP2, and OsTIP3 that are homologous to rice gamma-TIP cDNA. Northern blot hybridization analyses revealed that rice gamma-TIP was expressed in all plant organs. OsTIP1 was expressed in mature seed embryos and during early seed germination. OsTIP2 was expressed exclusively in roots. OsTIP3 was specifically expressed in seeds. These results suggest that the OsTIP1, OsTIP2, and OsTIP3 genes encode discrete, functionally specialized TIPs. Immunocytochemical analysis in rice endosperm cells revealed that rice gamma-TIP was localized only on the protein body type II (PB-II) membranes, whereas OsTIP3 was localized on the PB-II and the aleurone grain membranes. Although both the PB-II and the aleurone grain are derived from vacuoles, these results suggest that they may be derived from different types of vacuoles. (+info)
Antimicrobial actions of the human epididymis 2 (HE2) protein isoforms, HE2alpha, HE2beta1 and HE2beta2.
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BACKGROUND: The HE2 gene encodes a group of isoforms with similarities to the antimicrobial beta-defensins. We demonstrated earlier that the antimicrobial activity of HE2 proteins and peptides is salt resistant and structure dependent and involves permeabilization of bacterial membranes. In this study, we further characterize the antimicrobial properties of HE2 peptides in terms of the structural changes induced in E. coli and the inhibition of macromolecular synthesis. METHODS: E. coli treated with 50 microg/ml of HE2alpha, HE2beta1 or HE2beta2 peptides for 30 and 60 min were visualized using transmission and scanning electron microscopy to investigate the impact of these peptides on bacterial internal and external structure. The effects of HE2alpha, HE2beta1 and HE2beta2 on E. coli macromolecular synthesis was assayed by incubating the bacteria with 2, 10 and 25 microg/ml of the individual peptides for 0-60 min and measuring the incorporation of the radioactive precursors [methyl-3H]thymidine, [5-3H]uridine and L-[4,5-3H(N)]leucine into DNA, RNA and protein. Statistical analyses using Student's t-test were performed using Sigma Plot software. Values shown are Mean +/- S.D. RESULTS: E. coli treated with HE2alpha, HE2beta1 and HE2beta2 peptides as visualized by transmission electron microscopy showed extensive damage characterized by membrane blebbing, thickening of the membrane, highly granulated cytoplasm and appearance of vacuoles in contrast to the smooth and continuous membrane structure of the untreated bacteria. Similarly, bacteria observed by scanning electron microscopy after treating with HE2alpha, HE2beta1 or HE2beta2 peptides exhibited membrane blebbing and wrinkling, leakage of cellular contents, especially at the dividing septa, and external accumulation of fibrous materials. In addition, HE2alpha, HE2beta1 and HE2beta2 peptides inhibited E. coli DNA, RNA and protein synthesis. CONCLUSIONS: The morphological changes observed in E. coli treated with epididymal HE2 peptides provide further evidence for their membrane dependent mechanism of antibacterial action. HE2 C-terminal peptides can inhibit E. coli macromolecular synthesis, suggesting an additional mechanism of bacterial killing supplementary to membrane permeabilization. (+info)
Epidermal growth factor triggers an original, caspase-independent pituitary cell death with heterogeneous phenotype.
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Programmed cell death (PCD) is physiologically involved in the regulation of cell division and differentiation. It encompasses caspase-dependent mitochondrial and nonmitochondrial pathways. Additional caspase-independent pathways have been characterized in mitochondrial PCDs but remain hypothetical in nonmitochondrial PCDs. Epidermal growth factor (EGF) has been shown to inhibit division of pituitary somato-lactotrope cells occurring in parallel with EGF-mediated differentiation of these precursors into lactotrope cells. We show here that in somato-lactotrope pituitary cell line GH4C1, EGF triggers a PCD characterized by an apoptosis-like DNA fragmentation, insensitivity to broad-range caspase inhibitors, and absence of either cytochrome c or apoptosis-inducing factor release from mitochondria. Dying cells display loose chromatin clustering and numerous cytoplasmic vacuoles, a fraction of which are autophagic, thus conferring a heterogeneous phenotype to this PCD. Moreover, overexpression of cell death inhibitor Bcl-2 prevented not only the EGF-induced PCD but also its prodifferentiation effects, thus pointing to a mechanistic relationship existing between these two phenomena. Overall, the characterized differentiation-linked cell death represents an original form of caspase-independent PCD. The mechanisms underlying this PCD involve combinatorial engagement of discrete death effectors leading to a heterogeneous death phenotype that might be evolutionary related to PCD seen during the differentiation of some unicellular organisms. (+info)
Graft calcifications and dysfunction following liver transplantation.
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BACKGROUND: The molecular events, following ischemia and reperfusion (I/R) of the liver during transplantation are largely unknown. There is evidence that apoptotic and necrotic events may take place, and occasionally result in primary graft dysfunction. We herein report two cases, where significant I/R injury correlated with the development of liver calcification and primary liver dysfunction. CASE PRESENTATION: Both patients with clinical and biochemical evidence of primary graft dysfunction demonstrated calcification at light and electron microscopy levels. In addition, one patient had macroscopic evidence of calcification on cross-sectional imaging. Both patients died secondary to the sequelae of the graft dysfunction. CONCLUSIONS: Severe I/R-induced injury to the liver, clinically leads to graft dysfunction. This is due to advanced apoptotic and/or necrotic events at the hepatocyte level that may, on the most severe form, lead to calcification. The study of microcalcification at the early posttransplant period could provide insight in the events taking place following significant ischemia/reperfusion-induced injury to the graft. (+info)
Electrical detection of single viruses.
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We report direct, real-time electrical detection of single virus particles with high selectivity by using nanowire field effect transistors. Measurements made with nanowire arrays modified with antibodies for influenza A showed discrete conductance changes characteristic of binding and unbinding in the presence of influenza A but not paramyxovirus or adenovirus. Simultaneous electrical and optical measurements using fluorescently labeled influenza A were used to demonstrate conclusively that the conductance changes correspond to binding/unbinding of single viruses at the surface of nanowire devices. pH-dependent studies further show that the detection mechanism is caused by a field effect, and that the nanowire devices can be used to determine rapidly isoelectric points and variations in receptor-virus binding kinetics for different conditions. Lastly, studies of nanowire devices modified with antibodies specific for either influenza or adenovirus show that multiple viruses can be selectively detected in parallel. The possibility of large-scale integration of these nanowire devices suggests potential for simultaneous detection of a large number of distinct viral threats at the single virus level. (+info)
An ultrastructural study on cytotoxic effects of mono(2-ethylhexyl) phthalate (MEHP) on testes in Shiba goat in vitro.
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In this study, the effects of mono(2-ethylhexyl) phthalate (MEHP), one of metabolites of di(2-ethylhexyl) phthalate, on immature Shiba goat testes in vitro were examined. The testes of 2-month-old Shiba goats were cut into smaller pieces, and seeded in medium. At 1, 3, 6 and 9 hr after administration of MEHP at various concentrations (0, 100 nmol ml(-1), 1 nmol ml(-1), and 1 x 10(-3) nmol ml(-1), respectively), the specimens were obtained for light and transmission electron microscopic observations. As a result, at 1 hr after exposure to MEHP, the vacuolization and nuclear membrane rupture appeared in Sertoli cells. Such alterations tended to gradually increase in number in time and dose-dependent manners. Moreover, by MEHP treatment, apoptotic spermatogenic cells (characterized with chromatin condensation, cytoplasm shrinkage without membrane rupture, still functioning cell organelles, and packed cell contents in membrane-bounded bodies), apoptotic Sertoli cells (characterized with nuclear membrane lysis, nuclear condensation), necrotic spermatogenic cells (characterized with swollen and ruptured mitochondria, plasma membrane lysis, spilt cell contents, and chromatin clumps), and necrotic Sertoli cells (characterized with marginated chromatins along the nuclear membrane, ruptured vesicles within the MNB, some swollen and ruptured cell organelles, e.g. mitochondria) could be identified. Conclusively, ultrastructurally the treatment with MEHP at low concentration tends to lead spermatogenic and Sertoli cells to apoptosis, whereas that at high concentration tends to lead spermatogenic and Sertoli cells to necrosis. Thus, the testicular tissue culture is advantageous for screening testicular toxicity of chemicals. (+info)
Novel nuclear defects in KLP61F-deficient mutants in Drosophila are partially suppressed by loss of Ncd function.
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KLP61F in Drosophila and other BimC kinesins are essential for spindle bipolarity across species; loss of BimC function generates high frequencies of monopolar spindles. Concomitant loss of Kar3 kinesin function increases the frequency of bipolar spindles although the underlying mechanism is not known. Recent studies raise the question of whether BimC kinesins interact with a non-microtubule spindle matrix rather than spindle microtubules. Here we present cytological evidence that loss of KLP61F function generates novel defects during M-phase in the organization and integrity of the nuclear lamina, an integral component of the nuclear matrix. Larval neuroblasts and spermatocytes of klp61F mutants showed deep involutions in the nuclear lamina extending toward the centrally located centrosomes. Repositioning of centrosomes to form monopolar spindles probably does not cause invaginations as similar invaginations formed in spermatocytes lacking centrosomes entirely. Immunofluorescence microscopy indicated that non-claret disjunctional (Ncd) is a component of the nuclear matrix in somatic cells and spermatocytes. Loss of Ncd function increases the frequency of bipolar spindles in klp61F mutants. Nuclear defects were incompletely suppressed; micronuclei formed near telophase at the poles of bipolar spindle in klp61F ncd spermatocytes. Our results are consistent with a model in which KLP61F prevents Ncd-mediated collapse of a nonmicrotubule matrix derived from the interphase nucleus. (+info)