Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 29

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  growth inhibition
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The PKB signaling pathway is essential for cell survival and the inhibition of apoptosis, but its functional mechanisms have not been fully explored. Previously, we reported that TPA effectively inhibited PKB activity and caused PKB degradation, which was correlated with the repression of PKB phosphorylation at Ser473. In this study, we focus on how PKB is regulated by TPA in gastric cancer cells. One of the TPA targets, PKCα, was found to mediate the inhibition of PKB phosphorylation and degredation caused by TPA. Furthermore, TPA induced the import of PKCα into the nucleus, where PKCα exerted an inhibitory effect on PKB expression and phosphorylation. As a result, cancer cell proliferation was arrested. Our study characterizes a novel function of PKCα in mediating the negative regulation of PKB by TPA, and suggests a potential application in the clinical treatment of gastric cancer.
Sclerotinia sclerotiorum (Lib.) de Bary, the causal agent of Sclerotinia stem rot, is one of the most important pathogens of Brassica napus L. in northern Iran. In this study, 13 mycelial compatibility groups (MCGs) of the fungus were identified among 31 isolates sampled from four regions of Mazandaran province, Iran. Effective fungicides are useful in the integrated management of the disease. So, the effect of tebuconazole, propiconazole, cyproconazole, and Rovral-TS at five doses (0.0001, 0.001, 0.01, 0.1, and 1 ppm) was studied on the growth inhibition of S. sclerotiorum as in vitro tests. Maximum inhibition (100%) of S. sclerotiorum mycelial growth was obtained by the highest dose (1 ppm) of all tested fungicides, as well as by the doses of 0.1 and 0.01 ppm of propiconazole, cyproconazole, and tebuconazole. In this investigation, the reaction of S. sclerotiorum isolates belonging to different MCGs was evaluated against tebuconazole, propiconazole, cyproconazole, and Rovral-TS at their EC50 ranges. The results revealed that there was high variation of S. sclerotiorum MCGs against different fungicides. The inhibition percentage varied between 4.29% and 71.72%.
The synergistic effect of trimetrexate (TMTX) and sulphonamide derivatives of quinazoline on the cultured 5178Y murine leukemia cells was examined. On exposure to the slightly inhibitory concentrations of TMTX (0.1 nM) in combination with 2-desamino-2-methyl-10-propargyl-5,8-dideaza-pteroyl-sulphoglyc ine (DMPDDSF) (0.02 microM) a synergistic inhibitory effect of the antifolates on cell growth was observed. These two drugs in the same combination caused also synergistic inhibition of de novo synthesis of thymidylate in intact cells as measured by tritium release from [5-(3)H]deoxyuridylate. This was accompanied by a marked reduction in intracellular concentration of 5,10-methylenetetrahydro-pteroyl-polyglutamate (5,10CH2H4PteGlu(n)) (0.2 microM) and dihydropteroyl-polyglutamate (0.12 microM). In these conditions de novo biosynthesis of purine was decreased by 50%. These observations show that growth inhibition by combined antifolates is mediated by intracellular depletion of the substrate of thymidylate synthase -- 5,10CH2H4PteGlu(n). The results obtained strongly suggest that under certain conditions inhibition of thymidylate synthesis by DMPDDSF is intensified by prior application of TMTX -- an inhibitor of dihydrofolate reductase.
The effect of thymidylate synthase inhibitors, fluorodeoxyuridine (FdUrd) and its two sulphonamide derivatives was examined in the culture of murine leukemia cells -- 5178Y (parental subline) and its fluorodeoxyuridine resistant subline 5178Y/F. A synergistic effect of the antimetabolites on cell survival was observed on exposure of the culture of either line to a slightly inhibitory concentration of FdUrd (1 nM) in combination with 2-desamino-2-methyl-10-propargyl-5,8-dideaza-pteroylsulphogluta mate or 2-desamino-2-methyl-10-propargyl-5,8-dideaza-pteroylsulphoglyci ne. This effect was accompanied by a marked reduction, in both cell lines of intracellular concentration of 5,10-methylenetetrahydro-pteroyl-polyglutamate, although its concentration in the resistant subline was 3 times as high as in the parental line. The inhibitory effect of combined drugs on the cellular pool of folates in 5178Y line depended also on the sequence of drug addition, whereas in the FdUrd resistant line this sequence was without any effect. The results obtained strongly suggest that under certain conditions inhibition of thymidylate synthesis by antifolates is intensified by a prior use of FdUrd.
Effects of 62 isolates (of 41 taxa) of fungi on growth of 1-year-old oak (Quercus robur) seedlings were studied in an inoculation experiment. The fungi were isolated from roots of 80–96-year-old Q. robur that had been subjected to periodic flooding and had symptoms of oak decline. The fungal genera included Alternaria, Aspergillus, Calonectria, Chaetomium, Cladosporium, Clonostachys, Corynespora, Cylindrocarpon, Dicyma, Geotrichum, Ilyonectria, Isaria, Metarhizium, Oidiodendron, Ophiostoma, Pezicula, Phialocephala, Phialophora, Pyrenochaeta, Sporendocladia, Sporothrix, Thelonectria, Trichoderma and Trimmatostroma. Mycelial colonies of fungi growing in potato-dextrose broth were used for soil inoculation. Plant growth was assessed 2 years after inoculation, when the plants were 3 years old. Stem lengths, and dry weights of stems, roots and leaves were measured. Stem growth was inhibited by 31 isolates (50%) and root growth by 12 isolates (19%). Stem growth was stimulated by two isolates (3%) and root growth by 17 isolates (27%). The overall ratio of inhibitors to stimulants was 2.1. The proportion of taxa that inhibited stem growth was 16 times greater than that which promoted stem growth. The proportion of taxa that promoted root growth was only 1.5 times greater than that which inhibited root growth. The structure of the fungal communities in periodically flooded oak forests suggests that they are more likely to inhibit than to promote vigour in oaks.
Plants of ‘Catawbiense Boursault’ and ‘Eskimo’ rhododendrons or ‘Cannon’s Double’ and ‘Kilian’ azalea grown in 4 l containers were treated twice with chlormequat (2000, 4000 and 8000 mg · dm-3), trinexapac-ethyl (50, 100, 200, 400 mg · dm-3), daminozide (2500, 5000, 7500 mg · dm-3), proxeadione calcium (75, 150, 300 mg · dm-1) and once with paclobutrazol (50, 100, 200, 400 mg · dm-3). Shoot length of the subsequent growth flush following the treatments decreased with increasing rates of the growth retardants. The number of flower buds per plant increased with increasing rates of pacloburazol, chlormequat and daminozide. Prohexadione calcium was less effective in flower bud initiation and the worst results were obtained with trinexapac-ethyl.
Synthetic inhibitors of benzamidine type have been found to have inhibiting effects on arginine specific cysteine proteinases of P. gingivalis. The purpose of our study was to assess the effects of these inhibitors on the virulence properties of two P. gingivalis strains, the reference strain ATCC 33277 and JH16-1, a clinical isolate ob­tained from a patient with severe periodontitis. The inhibitors tested were pentami- dine, benzamidine, three bis-benzamidine derivatives with a pentamidine-related structure, one bis-benzamidine derivative with another structure, and one arginine derivative as a negative control, each in the concentrations of 2 uM and 20 uM. As vir­ulence criteria the following parameters were determined: arginine-specific amidolytic activity, growth inhibition, hemagglutination of sheep erythrocytes, adher­ence to KB cells and immuno-phagocytosis including intracellular killing. Pentami- dine and the bis-benzamidine derivatives with pentamidine-related structure showed the most remarkable effects on reduction of amidolytic activity by 35%, growth inhibi­tion and reduced hemagglutination. Except for the arginine derivative all other inhibi­tors tested enhanced the phagocytosis capacities of granulocytes. No clear influence of the inhibitors on adherence of P. gingivalis to KB cells was seen. Although in vitro effects of the synthetic inhibitors of cysteine proteinases on virulence of P. gingivalis were observed further in vitro tests concerning immunomodulatory effects should be done before these substances are used for therapy in clinically controlled studies.
This study was conducted on 25 animals randomly selected from a herd with 40 feedlot cattle, which had poor growth, rough hair coat, and change in the colour of the hair coat. Blood samples were collected from the vena jugularis into the tubes containing Na₂EDTA for the determination of plasma copper concentration and blood profile. Feed samples were also tested for copper, zinc, and molybdenum content. Ten healthy cattle were used as controls from different herds. In the affected group, mean plasma copper level was found to be at 6.43 µmol/L ± 0.01 and copper, molybdenum, and zinc levels in the diet were 15.55 ppm, 3.85 ppm, and 120 ppm, respectively. The mean plasma copper level in control animals was 13.50 µmol/L ±0.06). The difference was statistically significant (P<0.001). The deficiency of copper content may result from especially high molybdenum and zinc levels in the diet. When any finding indicative of this deficiency is observed in a herd, copper status of the animals should be determined. Then, copper and especially molybdenum and zinc concentration in the diet should be examined.
The antibacterial activities of five antibiotics, three brands of Ofloxacins (Obenasin, Floxavid and Drovid) and two brands of Ciprofloxacins (Uroxin and Siprosan), and five commonly used disinfectants (Lysol, Dettol, Purit, Roberts and Wex-cide) against Staphylococcus aureus, Escherichia coli, Proteus spp., Pseudomonas aeruginosa, Streptococcus spp. and Bacillus spp. were investigated. The growth inhibitory effect of both the antibiotics and disinfectants were determined using paper disk diffusion method and well-in-agar technique respectively. The highest mean zone of growth inhibition (19.3 mm) was given by Drovid on Streptococcus spp., while the smallest (7.0 mm) was by Floxavid on P. aeruginosa. Lysol had the highest mean zone of growth inhibition (18.0 mm) on Streptococcus spp. while P. aeruginosa and Bacillus spp. had no zone of growth inhibition with Roberts at 100-fold dilution. All the isolates were also resistant to Wex-cide. The test organisms were found to be significantly susceptible to the routinely used antimicrobials tested. However, there is the need for continuous surveillance for the detection of emerging resistance pattern.
Ability of five strains of Trichoderma pseudokoningii (antagonists) to suppress radial growth of Fusarium verticillioides (Sacc.) Nirenberg (=Fusarium moniliforme Sheldon) was examined i n vi tro. These were T. pseudokoningii strain1 (IMI 380933), strain2 (IMI 380937), strain3 (IMI 3809 39), strain4 (IMI 380940) and strain5 (IMI 380941). Each strain was paired with pathogen by inoculating at opposite ends of 9 cm petri plates using three pairing methods. Gradings were assigned to varied growth inhibition of pathogen by antagonists and analysed using GLM procedure (SAS). Growth suppressionof F. verticillioides by all strains of T. pseudokoningii was significantly different (R2 =0.98, p=0.05) from control in all pairing methods. It differed significantly (p>0.0003) among the strains in all pairing methods. Growth suppression also differed significantly among (p>0.0001) and within (p>0.018) pairing methods. Growth suppression was best when antagonists were inoculated before pathogen. Suppression mechanisms include mycoparasitism and competition for space and nutrients. T. pseudokoningii strains 3 and 4 had the best (p=0.05) growth suppressionof F. verticillioides and could be used as biocontrol agents for endophytic F. verticillioides in maize plant. This experiment was conducted in the search for resident microorganisms that might be capable of checking F. verticillioides withinmaize plant by competitive exclusion in subsequent experiments.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.