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981.
In this study, we explored the pathogenic mechanism of white spot syndrome virus (WSSV) in crayfish, Cherax quadricarinatus, by investigating activities of enzymes related to innate immune function during infection. After 6-12 h of exposure to WSSV, the activities of four enzymes, phenoloxidase (PO), peroxidase (POD), superoxide dismutase (SOD) and lysozyme (LSZ), increased in the gills of C. quadricarinatus but then sharply decreased during longer infection times. Except for PO, the activities of other enzymes in the WSSV-infected crayfish (Group II) were significantly lower than those of the controls at 72 h post-exposure (P < 0.01). Interestingly, the enzyme activities in the group treated with polysaccharides before challenge with WSSV (Group III) were higher than those in Group II. This phenomenon demonstrated that the polysaccharides could improve the immuno-enzyme activities and enhance the organism's antiviral defenses. Morphological examination by transmission electron microscopy revealed abundant WSSV particles and significant damage in the gills of infected crayfish. WSSV infection caused parts of the gill epithelium and microvilli to be reduced in number and size or damaged; meanwhile, the mitochondria morphology changed, with parts of the cristae diminished leaving large vacuoles. Moreover, electron dense deposits appeared and heterochromatinized nuclei could be seen in blood cells with ruptured nuclear membranes and outflow of nucleoplasm. The findings of this study furthers our understanding of the biochemical alterations induced by viral infections, including changes in the antioxidant status, oxidative stress and lysozyme activity, which could help to advance strategies for control of WSSV in crayfish. 相似文献
982.
The study was conducted to investigate the effects of dietary n-3 highly unsaturated fatty acid (n-3 HUFA) on growth, nonspecific immunity, expression of some immune related genes and disease resistance of juvenile large yellow croaker (Larmichthys crocea) following natural infestation of parasites (Cryptocaryon irritans). Six isoproteic and isolipidic diets were formulated with graded levels of n-3 HUFA ranging from 0.15% to 2.25% of the dry weight and the DHA/EPA was approximately fixed at 2.0. Each diet was randomly allocated to triplicate groups of fish in floating sea cages (1.0 × 1.0 × 1.5 m), and each cage was stocked with 60 fish (initial average weight 9.79 ± 0.6 g). Fish were fed twice daily (05:00 and 17:00) to apparent satiation for 58 days. Results showed that moderate n-3 HUFA level (0.98%) significantly enhanced growth compared with the control group (0.15% HUFA) (P < 0.05), while higher n-3 HUFA levels (1.37%, 1.79% and 2.25%) had detrimental effects on the growth though no significance was found (P > 0.05). Nitro blue tetrazolium (NBT) positive leucocytes percentage of head kidney and serum superoxide dismutase (SOD) activity increased with increasing n-3 HUFA from 0.15% to 0.60%, and decreased with further increase of n-3 HUFA from 0.60% to 2.25% (P < 0.05). Serum lysozyme activity increased significantly as n-3 HUFA increased from 0.15% to 1.37%, and then decreased with n-3 HUFA from 1.37% to 2.25% (P > 0.05). There were no significant differences in phagocytosis index (PI) of head kidney leucocytes among dietary treatments (P > 0.05). The hepatic mRNA expression of Toll-like receptor 22 (TLR22) and Myeloid differentiation factor 88 (MyD88) was significantly up-regulated in fish fed the diets with low or moderate levels, while in kidney this increment was only found at specific sampling time during the natural infestation of parasites. The 13 d cumulative mortality rate following natural infestation of parasites decreased with n-3 HUFA increased from 0.15% to 0.60% (P < 0.05), and significantly increased with n-3 HUFA from 0.60% to 2.25% (P < 0.05). Results of this study suggested that fish fed low or moderate dietary n-3 HUFA had higher growth, nonspecific immune responses, expression levels of some immune related genes and disease resistance of large yellow croaker following natural infestation of parasites and dietary n-3 HUFA may regulate fish immunity and disease resistance by altering the mRNA expression levels of TLR22 and MyD88. 相似文献
983.
The pineal hormone melatonin has been shown to have anticancer therapeutic properties in patients with gastric cancer, the
mechanisms, however, remain largely unknown. The present study examined the effects of melatonin on cell differentiation related
factors, namely, endocan, alkaline phosphatase, and lactate dehydrogenase, in gastric adenocarcinoma cell line SGC7901. Expression
of endocan was significantly decreased in tissue of gastric cancer as compared to normal stomach tissue, as determined by
immunohistochemical staining, and there is correlation between the degree of the decrease of endocan expression and the degree
of differentiation of the cancer. Treatment of cultured gastric adenocarcinoma cells with 10−4 mol/l melatonin significantly increased the gene expression of endocan and down-regulated the activity of alkaline phosphatase
and lactate dehydrogenase, two enzymes that promote de-differentiation in gastric tissue; and there was a negative correlation
between the level of endocan expression and the activities of differentiation marker enzymes in the melatonin treated cancer
cells. Gastric cancer cells treated with melatonin show more differentiated morphologic phenotype as compared the untreated
cells. The findings indicate that melatonin may play its anticancer role in gastric adenocarcinoma by acting as a differentiation
inducer. 相似文献
984.
To study the prevalence and isoforms of the pathogenicity island ETT2 among pathogenic Escherichia coli, as well as to determine the relationship between the ETT2 locus and other virulence factors, PCR amplifications target to
the 35 ETT2-associated genes were established and used to investigate the presence of the ETT2 locus in 168 E. coli isolates from weaned piglets with edema and/or diarrhea or dairy cows with mastitis. The results showed that the ETT2 locus
could be identified in the pathogenic E. coli isolates from colibacillosis in pigs and in the ones from mastitis in cows, but the presence of ETT2 among the isolates of
porcine origin were significantly higher (85.87%) than that (47.37%) of bovine origin. Furthermore, 11 ETT2 isoforms were
found in this research, including an intact form and 10 deletion types. The intact ETT2 was the prevalent form among the pathogenic
E. coli isolates of porcine origin, and highly associated with the presence of shigatoxin type 2e (Stx2e), while the great majority
isolates of bovine origin just carried various deletion types, and no distinct association with other virulence factors, e.g.,
the presence/absence of LT1, ST2, Cnf2, Tra, HPI, Hly, and F17a fimbriae. 相似文献
985.
The small GTPase Cdc42 has been implicated as an important regulator of cell migration. However, whether Cdc42 plays similar role in all cancer cells irrespective of metastatic potential remains poorly defined. Here, we show by using three different breast cancer cell lines with different metastatic potential, the role of Cdc42 in cell migration/invasion and its relationship with a number of downstream signaling pathways controlling cell migration. Small interfering RNA (siRNA)-mediated knockdown of Cdc42 in two highly metastatic breast cancer cell lines (MDA-MB-231 and C3L5) resulted in enhancement, whereas the same in moderately metastatic (Hs578T) cell line resulted in inhibition of intrinsic cellular migration/invasion. Furthermore, Cdc42 silencing in MDA-MB-231 and C3L5 but not Hs578T cells was shown to be accompanied by increased RhoA activity and phosphorylation of protein kinase C (PKC)-δ, extracellular signal regulated kinase1/2 (Erk1/2), and protein kinase A (PKA). Pharmacological inhibition of PKCδ, MEK-Erk1/2, or PKA was shown to inhibit migration of both control and Cdc42-silenced MDA-MB-231 cells. Furthermore, introduction of constitutively active Cdc42 was shown to decrease migration/invasion of MDA-MB-231 and C3L5 but increase migration/invasion of Hs578T cells. This decreased migration/invasion of MDA-MB-231 and C3L5 cells was also shown to be accompanied by the decrease in the phosphorylations of PKCδ, Erk1/2, and PKA. These results suggested that endogenous Cdc42 could exert a negative regulatory influence on intrinsic migration/invasion and some potentially relevant changes in phosphorylation of PKCδ, Erk1/2, and PKA of some aggressive breast cancer cells. 相似文献
986.
Juan Wang Wen-Yuan Gao Jian Zhang Bei-Mei Zuo Li-Ming Zhang Lu-Qi Huang 《Acta Physiologiae Plantarum》2012,34(2):397-403
Panax ginseng C. A. Meyer is one of the important nutraceutical and medicinal plants, which is used worldwide. Until now, ginseng has been
reported to contain saponins, antioxidants, peptides, polysaccharides, fatty acids, vitamins, alkaloids, lignans, and flavonoids.
The saponins, known as ginsenosides, are widely believed to be the major bioactive compounds of ginseng. In this article,
ginsenoside biosynthesis pathway and key enzymes regulation are also described. This review provides a reference for improving
ginsenoside contents through regulation of ginsenoside biosynthesis pathway. 相似文献
987.
The purpose of this 42-day study was to investigate the apoptosis in the bursa of Fabricius induced by different levels of
dietary vanadium. A total of 420 1-day-old avian broilers were divided into 6 groups in which there were 7 replicates in each
group and 10 broilers in each replicate and fed on a corn–soybean basal diet as control diet (vanadium 0.073 mg/kg) or the
same diet amended to contain 5, 15, 30, 45, and 60 mg/kg vanadium supplied as ammonium metavanadate (NH4VO3). Ultrastructurally, mitochondrial injury and increased numbers of apoptotic cells with condensed nuclei were observed in
the 30, 45, and 60 mg/kg groups. As measured by flow cytometry, the percentages of apoptotic lymphocytes were significantly
increased in the 15-, 30-, 45-, and 60-mg/kg groups when compared with those of control group. Meanwhile, the terminal deoxynucleotidyl
transferase 2′-deoxyuridine 5′-triphosphate nick end-labeling assay showed that there were increased numbers of apoptotic
cells in the 30-, 45-, and 60-mg/kg groups. Immunohistochemical tests showed increased numbers of positive cells under Bax
and caspase-3 protein detection and decreased Bcl-2 protein in the 15-, 30-, 45-, and 60-mg/kg groups. The vanadium content
of the bursa was found to be significantly increased in the 30-, 45-, and 60-mg/kg groups. These results suggested that dietary
vanadium in excess of 15 mg/kg could cause lymphocyte apoptosis in the bursa of Fabricius and impact humoral immunity in broilers.
Lymphocyte apoptosis in the bursa induced by high levels of dietary vanadium is associated with mitochondrial injury and changes
in levels of apoptogenic proteins, such as Bcl-2, Bax, and caspase-3. 相似文献
988.
The aim of the current study was to assess relationships between multiple metals burden in human seminal plasma and semen quality parameters. Levels of five metals (lead, manganese, copper, arsenic, and selenium) in human seminal plasma were determined by inductively coupled plasma mass spectrometry (ICP-MS), and the correlations between the metal concentrations and semen parameters (sperm concentration, sperm motility rate, and sperm morphology) were analyzed. The activities of acid phosphatase (ACP) and of α-glucosidase in human seminal plasma were also determined. Of the 100 subjects, 21 had fertility problems according to the World Health Organization criteria and were designated as "abnormal group." Significant inverse correlations were found between the concentrations of Cu, As, Pb, and the sperm concentrations (r (Cu)?=?-0.312, P (Cu)?= 0.029; r (As)?=?-0.328, P (As)?= 0.021; r (Pb)?=?-0.377, P (Pb)?= 0.008). Moreover, the Cu, Mn, and Se concentrations were significantly higher in the abnormal group than that in the normal group (P (Cu)?= 0.024, P (Mn)?= 0.002, P (Se)?= 0.002). The ACP activity was significantly higher in the normal group than that in the abnormal group (P = 0.021). We also found a significantly negative correlation between α-glucosidase activity and the levels of As (r =?-0.367, P = 0.023). These findings provide evidence for relationships between human semen quality and metal exposures. These relationships are consistent with animal data, but additional human and mechanistic studies are needed. 相似文献
989.
Peng X Cui H He Y Cui W Fang J Zuo Z Deng J Pan K Zhou Y Lai W 《Biological trace element research》2012,145(1):47-51
Three hundred 1-day-old avian broilers were fed on a basic diet (0.2 mg/kg selenium) or the same diet amended to contain 1,
5, 10, and 15 mg/kg selenium supplied as sodium selenite (n = 60/group). In comparison with those of 0.2 mg/kg selenium group, the percentages of annexin V-positive splenocytes were
increased in 5, 10, and 15 mg/kg selenium groups. TUNEL assay revealed that apoptotic cells with brown-stained nuclei distributed
within the red pulp and white pulp of the spleens with increased frequency of occurrence in 10 and 15 mg/kg selenium groups
in comparison with that of 0.2 mg/kg Se group. Sodium selenite-induced oxidative stress in spleens of chickens was evidenced
by decrease in glutathione peroxidase, superoxide dismutase, and catalase activities and increase in malondialdehyde contents.
The results indicate that excess dietary selenium in the range of 5–15 mg/kg of feed causes oxidative stress, which may be
mainly responsible for the increased apoptosis of splenocytes in chickens. 相似文献
990.
The interactions between Urinary Trypsin Inhibitor (UTI) and 1-anilino-8-naphthalene sulfonate (ANS) were investigated by fluorescence spectra, isothermal titration calorimetry and molecular modeling. The results revealed the presence of four specific binding sites for ANS on UTI, with interactions driven mainly by electrostatic forces. The four specific binding sites indicated the involvement of four hydrophobic patches on UTI. Experimental data also confirmed the presence of a further five nonspecific binding sites that interacted mainly by the formation of salt bridges between the sulfonates of ANS and positive residues on the surface of UTI. 相似文献