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Inhibitory Substances (inhibitory + substance)
Selected AbstractsAntagonistic activity of Aeromonas media strain A199 against Saprolegnia sp., an opportunistic pathogen of the eel, Anguilla australis RichardsonJOURNAL OF FISH DISEASES, Issue 3 2003M J Lategan Abstract A bacteriocin-like inhibitory substance (BLIS) produced by Aeromonas media strain A199 inhibited the growth of Saprolegnia sp. in vitro, an opportunistic pathogen isolated from affected eels, Anguilla australis (Richardson). The presence of BLIS in solid media inhibited the growth of the vegetative state of the aquatic mould as well as the germination of cysts. Uninhibited growth was, however, observed in the presence of inactive BLIS, suggesting that the in vitro antagonism derived from the BLIS of A199. In four independent in vivo tank observations of fish affected with saprolegniosis, the daily addition of A199 to tank water contributed to the subsequent swift recovery of affected hosts from invasion by this opportunistic pathogen. [source] Neurally released ATP mediates endothelium-dependent hyperpolarization in the circular smooth muscle cells of chicken anterior mesenteric arteryBRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2005Marwan Draid The object of the present study was to clarify the neurotransmitter(s) controlling membrane responses to electrical field stimulation (EFS) in the circular smooth muscle cells of first-order branches of chicken anterior mesenteric artery. EFS (five pulses at 20 Hz, 1 ms) evoked a hyperpolarization of amplitude ,21.6±1.2 mV, total duration 21.8±1.2 s and latency 641.7±81.9 ms. The response was tetrodotoxin-sensitive and nonadrenergic noncholinergic (NANC) in nature. The NANC response was blocked by the nonspecific purinergic antagonist, suramin, indicating that the response is mediated by the neurotransmitter adenosine 5,-triphosphate (ATP). Either desensitization or blockade of P2Y receptor with its putative agonist 2-methylthioATP (1 ,M for 30 min) or with its antagonist cibacron blue F3GA (10 ,M), respectively, abolished the purinergic hyperpolarization. PPADS at concentrations up to 100 ,M had no effect on the EFS-induced response, indicating that this response is mediated through P2Y, but not P2X, receptor. In addition, the response was completely abolished by two specific P2Y1 receptor antagonists, namely, MRS 2179 (300 nM) and A3P5PS (10 ,M). Removal of the endothelium abolished the purinergic hyperpolarization, which was converted, in some preparations, to a small depolarization, indicating that the hyperpolarizing response is endothelium-dependent. The present study suggests that in first-order branches of chicken anterior mesenteric artery, ATP released from perivascular nerves may diffuse to the endothelium-activating P2Y1 receptor to induce release of an inhibitory substance that mediates hyperpolarization in the circular smooth muscle. British Journal of Pharmacology (2005) 146, 983,989. doi:10.1038/sj.bjp.0706413 [source] Changes in markers of ovarian reserve and endocrine function in young women with breast cancer undergoing adjuvant chemotherapyCANCER, Issue 9 2010Bo Yu MD Abstract BACKGROUND: Premenopausal women undergoing chemotherapy are at risk for amenorrhea and impaired fertility. The objective of the current study was to assess levels of mullerian inhibitory substance (MIS), estradiol (E2), follicle-stimulating hormone (FSH), and menstrual status, in women undergoing chemotherapy. METHODS: A nested prospective cohort study was conducted in women aged <40 years with breast cancer (BC) who were undergoing adjuvant chemotherapy (n = 26). Serum MIS, FSH, and E2 were measured before chemotherapy (baseline) and at Weeks 6, 12, 36, and 52. Controls were 134 age-matched women with known fertility. Hormone levels were compared between the cases and controls at baseline. Differences between amenorrhea and age subgroups were tested using the nonparametric Wilcoxon 2-sample test using a 2-sided , of 0.05. RESULTS: Subjects with BC and age-matched controls had similar baseline MIS levels (median, 0.94 ng/mL vs 0.86 ng/mL;, P > .05). Serum MIS decreased significantly at 6 weeks and remained suppressed for 52 weeks. E2 levels decreased, and FSH levels increased during chemotherapy; however, at 52 weeks, the levels returned to baseline. At 52 weeks, only 1 patient had MIS above the lower normal range, 15 had return of menstrual function, 11 had premenopausal levels of FSH, and 13 had follicular phase levels of E2. In women aged <35 years, 25% remained amenorrheic, whereas in women aged >35 years, 50% were amenorrheic. Amenorrheic and menstruating women were found to have similar MIS values at baseline and follow-up. CONCLUSIONS: In young women with BC, chemotherapy decreases MIS rapidly and dramatically. Rapid reductions in MIS do not appear to be predictive of subsequent menstrual function. Ovarian reserve and endocrine function may be affected differently by chemotherapy. Cancer 2010. © 2010 American Cancer Society. [source] Multiple displacement amplification as a pre-polymerase chain reaction (pre-PCR) to process difficult to amplify samples and low copy number sequences from natural environmentsENVIRONMENTAL MICROBIOLOGY, Issue 7 2005Juan M. Gonzalez Summary Microbial assessment of natural biodiversity is usually achieved through polymerase chain reaction (PCR) amplification. Deoxyribonucleic acid (DNA) sequences from natural samples are often difficult to amplify because of the presence of PCR inhibitors or to the low number of copies of specific sequences. In this study, we propose a non-specific preamplification procedure to overcome the presence of inhibitors and to increase the number of copies prior to carrying out standard amplification by PCR. The pre-PCR step is carried out through a multiple displacement amplification (MDA) technique using random hexamers as priming oligonucleotides and ,29 DNA polymerase in an isothermal, whole-genome amplification reaction. Polymerase chain reaction amplification using specific priming oligonucleotides allows the selection of the sequences of interest after a preamplification reaction from complex environmental samples. The procedure (MDA-PCR) has been tested on a natural microbial community from a hypogean environment and laboratory assemblages of known bacterial species, in both cases targeting the small subunit ribosomal RNA gene sequences. Results from the natural community showed successful amplifications using the two steps protocol proposed in this study while standard, direct PCR amplification resulted in no amplification product. Amplifications from a laboratory assemblage by the two-step proposed protocol were successful at bacterial concentrations ,,10-fold lower than standard PCR. Amplifications carried out in the presence of different concentrations of fulvic acids (a soil humic fraction) by the MDA-PCR protocol generated PCR products at concentrations of fulvic acids over 10-fold higher than standard PCR amplifications. The proposed procedure (MDA-PCR) opens the possibility of detecting sequences represented at very low copy numbers, to work with minute samples, as well as to reduce the negative effects on PCR amplifications of some inhibitory substances commonly found in environmental samples. [source] Evaluation of extracts of Jatropha curcas and Moringa oleifera in culture media for selective inhibition of saprophytic fungal contaminantsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 3 2009Grace Mebi Ayanbimpe Abstract Most fungi occur in nature and utilize simple sources of carbohydrates and nitrogen for growth. Sabouraud's dextrose agar has been an ideal medium for primary isolation of fungi from clinical specimens, but for specimens from nonsterile sites or heavily contaminated ones, it has been necessary to include inhibitory substances such as antibiotics like chloramphenicol (antibacterial) and cycloheximide (antifungal). The problems we have in the our laboratory owing to frequent contamination of cultures and the delays in the procurement of cycloheximide have stimulated a search for alternatives in our local environment to enhance effective laboratory diagnoses of fungal infections. Purified extracts of the leaves and bark of Jatropha curcas and Moringa oleifera (common plants in our locality) were tested against clinical isolates of fungi at various concentrations to determine the minimum inhibitory concentration at which common fungal contaminants are inhibited, without affecting the growth of the pathogenic fungi sought for. At a concentration of 0.75,mg,ml,1 contaminants were totally inhibited by the leaf extracts. The bark extracts did not inhibit any fungus even at higher concentrations. From the results it was evident that the leaf extracts of both plants have potentials for use as inhibitory substances in culture media against contaminant fungi including Aspergillus spp., Penicillium spp., etc. J. curcas and M. oleifera are very common plants in our locality. They can be obtained at almost no cost and at any time needed. The benefits of these findings to mycology laboratories in a developing country are enormous. J. Clin. Lab. Anal. 23:161,164, 2009. © 2009 Wiley-Liss, Inc. [source] TNF-, from monocyte of patients with pre-eclampsia-induced apoptosis in human trophoblast cell lineJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 4 2007Hiroyuki Seki Abstract Objective:, In pre-eclampsia, fetal growth restriction is frequently observed, and the possible involvement of inhibitory substances on trophoblast cell proliferation and differentiation has been suggested. The objective of this study was to investigate the effects humoral factors, such as cytokines, produced in immune cells on proliferation of an immortalized trophoblastic cell line (TCL) that we established. Methods:, Serum and lymphocyte layers were isolated from the blood of normal pregnant and preeclamptic women. The lymphocyte layer was further fractionated into different immune cell populations by the Stem Sep method. Immortalized trophoblastic cells were cultured with the sera diluted. The cytokine concentrations in the supernatants of lymphocyte cultures were compared between normal pregnancy and pre-eclampsia. The number, DNA content and induced apoptosis were examined on the immortalized trophoblastic cells at the end of culture. Results:, The sera from preeclamptic women significantly inhibited the immortalized trophoblastic cell proliferation in comparison with those from normal pregnancy. Among the lymphocyte fractions, monocytes significantly inhibited the immortalized trophoblastic cell proliferation. The monocytes from preeclamptic women were found to produce higher levels of tumor necrosis factor-, (TNF-,) in the culture supernatant than those from normal pregnant women. The coculture with the monocytes from preeclamptic women increased the frequency of TUNEL-positive TCL cells. TNF-, inhibited immortalized trophoblastic cell proliferation in a dose-dependent manner and induced apoptosis. Conclusion:, The present results suggest that monocytes are activated and that cytokines, such as TNF-,, which is produced by monocytes, induce apoptosis and inhibit proliferation of trophoblast cells in pre-eclampsia. [source] Postoperative serum attenuates LPS-induced release of TNF-, in orthopaedic surgeryJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2007Olav Reikerås Abstract Studies with ex vivo stimulation of whole blood samples from injured patients have revealed a diminished production capacity for a broad range of secretory products, including inflammatory cytokines. Recent interest has focused on the release of mediators in serum that depress the cell-mediated immune response following trauma. The involvement of the lipid mediator prostaglandin E2 (PGE2) has been assumed because it is a potent endogenous immunosuppressor. In the present study, we tested the hypothesis that inhibitory substances circulating in the patient's serum after a major musculoskeletal trauma might impair leukocyte function by evaluating the effect of such serum on cytokine release in a whole blood model. Six females and three males undergoing elective total hip replacement were included in the study. Ex vivo LPS-induced TNF-, and IL-10 were measured in whole blood sampled preoperatively and added serum taken before, at the end of operation, and at postoperative days 1 and 6 with saline as negative control. LPS induced significant releases of TNF-, and IL-10 in whole blood. Addition of preoperative, postoperative, and day-1 postoperative serum did not alter the LPS-induced release of TNF-, as compared to saline. In the presence of serum from postoperative day 6, however, the expression of TNF-, was significantly reduced as compared to saline and preoperative serum (p,=,0.021 and 0.008, respectively). Neither of the serum samples altered the release of IL-10. PGE2 was significantly (p,=,0.008) increased in serum at postoperative day 6 as compared to preoperative levels. In conclusion, these data show that at day 6 after major orthopaedic surgery, the patient serum contained activity that inhibited ex vivo LPS-induced TNF-, release. The potent TNF-, inhibitory activity found at day 6 after injury correlated with increased levels of PGE2 and indicates cell-mediated hyporesponsiveness to a second stimulus. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1395,1400, 2007 [source] Influence of baking enzymes on antimicrobial activity of five bacteriocin-like inhibitory substances produced by lactic acid bacteria isolated from Lithuanian sourdoughsLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2008V. Narbutaite Abstract Aim:, To evaluate the effect of four different baking enzymes on the inhibitory activity of five bacteriocin-like inhibitory substances (BLIS) produced by lactic acid bacteria (LAB) isolated from Lithuanian sourdoughs. Methods and Results:, The overlay assay and the Bioscreen methods revealed that the five BLIS exhibited an inhibitory effect against spore germination and vegetative outgrowth of Bacillus subtilis, the predominant species causing ropiness in bread. The possibility that the observed antibacterial activity of BLIS might be lost after treatment with enzymes used for baking purposes was also examined. Conclusions:, The enzymes tested; hemicellulase, lipase, amyloglucosidase and amylase had little or no effect on the majority of the antimicrobial activities associated with the five BLIS studied. Significance and Impact of the Study:, This study suggests a potential application in the sourdough baking industry for these antimicrobial producing LAB strains in the control of B. subtilis spore germination and vegetative outgrowth. [source] Chemistry and biology of phototropism-regulating substances in higher plantsTHE CHEMICAL RECORD, Issue 5 2001Shosuke Yamamura Abstract Most people are familiar with the sight of a young seedling bending towards a window or the brightest source of light to which it is exposed. This directional growth response is known as phototropism, which is caused by a lateral growth-promoting auxin in the bending organ (Cholodny-Went theory, cited in high school textbook). Recently, however, Bruinsma et al., Weiler et al., and Hasegawa et al. independently found that the shaded half did not contain more auxin than the illuminated one. Instead it was found that the even distribution of auxin was accompanied by a lateral gradient of growth inhibiting substances during phototropic curvature (Bruinsma-Hasegawa theory). We have isolated some photo-induced growth inhibitory substances related to phototropism, benzoxazolinones from light-grown maize shoots (Zea mays L.), raphanusanins from radish hypocotyl (Raphanus sativus var. hortensis f. gigantissimus M.), indolyacetonitrile from light-grown shoots (Brassica oleacea L.), 8-epixanthatin from sunflower hypocotyl (Helianthus annus L.), and quite recently uridine from oat coleoptile (Avena sativa L.). Chemical analyses have shown phototropic stimulations to cause curvature by inducing a local unequal distribution of growth-inhibiting substances that antagonize auxin in its cell-elongating activity. Finally, a model is presented for further studies on phototropism. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:362,372, 2001 [source] Comparison of methods of DNA extraction for real-time PCR in a model of pleural tuberculosisAPMIS, Issue 1 2010ANA SANTOS Santos A, Cremades R, Rodríguez JC, García-Pachón E, Ruiz M, Royo G. Comparison of methods of DNA extraction for real-time PCR in a model of pleural tuberculosis. APMIS 2010; 118: 60,5. Molecular methods have been reported to have different sensitivities in the diagnosis of pleural tuberculosis and this may in part be caused by the use of different methods of DNA extraction. Our study compares nine DNA extraction systems in an experimental model of pleural tuberculosis. An inoculum of Mycobacterium tuberculosis was added to 23 pleural liquid samples with different characteristics. DNA was subsequently extracted using nine different methods (seven manual and two automatic) for analysis with real-time PCR. Only two methods were able to detect the presence of M. tuberculosis DNA in all the samples: extraction using columns (Qiagen) and automated extraction with the TNAI system (Roche). The automatic method is more expensive, but requires less time. Almost all the false negatives were because of the difficulty involved in extracting M. tuberculosis DNA, as in general, all the methods studied are capable of eliminating inhibitory substances that block the amplification reaction. The method of M. tuberculosis DNA extraction used affects the results of the diagnosis of pleural tuberculosis by molecular methods. DNA extraction systems that have been shown to be effective in pleural liquid should be used. [source] | |||||||||||||