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排序方式: 共有103条查询结果,搜索用时 406 毫秒
1.
MORPHOLOGICAL CHANGES AND THE REQUIREMENTS FOR MACROMOLECULE SYNTHESIS DURING EXCYSTMENT OF ACANTHAMOEBA CASTELLANII
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Light and phase-contrast microscopic observations of excystment in Acanthamoeba castellanii have been used to classify cells in excysting populations as free trophozoites, or mature, activated, or preemergent cysts. These categories have been used to describe the kinetics of excystment. A pH of 7 and a temperature of 30°C have been found to be optimal for the activation of mature cysts. Both activation and emergence are inhibited by cycloheximide and actinomycin D, but neither process is much affected by hydroxyurea. Cell-free extracts of high molecular weight components of cyst cytoplasm can support protein synthesis in vitro, although less efficiently than similar extracts from trophozoites. Evidence indicates that some of the functional RNA in the cyst extracts is synthesized before excystment. 相似文献
2.
Summary The effects of different concentrations of KCl, K2SO4, MgCl2 and MgSO4 on the growth in length of the first seminal root of wheat, and on the change in fresh and oven-dry weight of the seedling
and its component parts have been studied. The effect of mannitol was also investigated for comparison and to study the osmotic
action.
The effect of salts on root growth was dependent on salt species; all effects were specific to ions and not due to osmotic
activity of solution.
The growth of wheat roots was suppressed by concentrations of salts much lower than those required to suppress germination.
All solutions of KCl from 0.1 to 50 me/l checked the growth of the root; the retardation increased with increase of concentration.
In K2SO4 there was a slight activation of root growth for one day in 0.1 and 0.5 me/l; then the growth was suppressed after that.
In all other concentrations from 1 to 50 me/l the growth was retarded.
In MgCl2 or MgSO4 there was some activation of root elongation in 0.05, 0.1 and 0.5 me/l; but higher concentrations retarded root growth. 相似文献
3.
Mona A. Kortam Bassam Mohamed Ali Nevine Fathy 《Journal of biochemical and molecular toxicology》2021,35(1)
This study aimed to uncover the protective potentiality of resveratrol and dimethyl fumarate (DMF) in the liver of a chronic unpredictable mild stress (CUMS)‐induced depression animal model. Resveratrol and DMF significantly alleviated CUMS‐induced behavioral abnormalities in stressed rats through improving sucrose preference in sucrose preference test and decreasing immobility time in a forced swimming test. They also mitigated serum corticosterone levels and elevated serum serotonin levels, which were formerly disturbed in CUMS rats. The hepatoprotective effect is evidenced by improvement in hepatic histopathological examinations, as well as normalized serum alanine aminotransferase and aspartate aminotransferase activities. Molecular signaling of resveratrol and DMF was estimated by diminishing hepatic expression of phosphorylated p38 mitogen‐activated protein kinase (MAPK), extracellular signal‐regulated kinase1/2 (ERK1/2), and c‐Jun N‐terminal kinase (JNK). Consequently, they improved the hepatic antioxidant and anti‐inflammatory activities as elaborated by the normalization of total antioxidant capacity, glutathione, malondialdehyde, nuclear factor‐κB, tumor necrosis factor‐α, and myeloperoxidase levels. In addition, they inhibited hepatocyte apoptosis as evidenced by the increased expression of B‐cell lymphoma 2, the decreased expression of Bax, as well as the suppressed activity of caspase‐3. In conclusion, resveratrol and DMF purveyed a significant anti‐depressant effect, which may be mediated, at least in part, via inhibiting the MAPK/ERK/JNK pathway in the CUMS rat model. 相似文献
4.
Mohamed-Elamir F. Hegazy Tarik A. Mohamed Fathy F. Abdel-Latif Mansour S. Alsaid Abdelaaty A. Shahat Paul W. Paré 《Phytochemistry letters》2013,6(3):383-386
Chemical investigations of the soft coral Sarcophyton trocheliophorum, has led to the isolation of six cembranoids, two of which are new, Trochelioid A (1) and B (2), and one, 16-oxosarcophytonin E (3) isolated from nature for the first time. Additionally, two have been isolated from S. trocheliophorum for the first time (4 and 6). Structures were elucidated by employing extensive NMR and HR-FAB-MS experimentation. 相似文献
5.
Rehab Mohammad Yusif Irhan Ibrahim Abu Hashim Elham Abdelmonem Mohamed Farid Abd-Elreheim Badria 《AAPS PharmSciTech》2016,17(2):328-338
Currently available anti-ulcer drugs suffer from serious side effects which limited their uses and prompted the need to search for a safe and efficient new anti-ulcer agent. Boswellia gum resin (BR) emerged as a safe, efficient, natural, and economic potential cytoprotective agent. Thus, it is of medical importance to develop gastroretentive (GR) formulations of BR to enhance its bioavailability and anti-ulcer efficacy. Early attempts involved the use of organic solvents and non-applicability to large-scale production. In this study, different tablet formulations were prepared by simple direct compression combining floating and bioadhesion mechanisms employing hydroxypropyl methylcellulose (HPMC), sodium carboxymethyl cellulose (SCMC), pectin (PC), and/or carbopol (CP) as bioadhesive polymers and sodium bicarbonate (SB) as a gas former. The prepared tablets were subjected for assessment of swelling, floating, bioadhesion, and drug release in 0.1 N HCl. The optimized GR formulation was examined for its protective effect on the gastric ulcer induced by indomethacin in albino rabbits compared with lactose tablets. The obtained results disclosed that swelling, floating, bioadhesion, and drug release of the GR tablets of BR depend mainly on the nature of the matrix and the ratio of polymer combinations. Moreover, a combination of SCMC-CP in a ratio of 2:1 (SCP21) exhibited desirable floating, bioadhesion, swelling, and extended drug release. Also, a 6-h pretreatment with SCP21 tablets decreased the severity of inflammation and number of bleeding spots among ulcer-induced rabbits in comparison to those treated with lactose tablets. 相似文献
6.
Amina M. Ibrahim Amira Kamal Ahmed Fayez A. Bakry Ibrahim Rabei Fathy Abdel-Ghaffar 《Molluscan research.》2019,39(3):224-233
ABSTRACTBiomphalaria alexandrina snails have been used as bioindicators for freshwater qaulity and the effects of some herbicides such as butralin, glyphosate-isopropylammonium and pendimethalin). In the present study the effect of these three herbicides on snail biochemistry was examined. The results indicated that the herbicides increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the haemolymph of B. alexandrina snails and significantly decreased total protein and albumin content. Light microscopical examinations of haemocytes monolayers of B. alexandrina snails showed three different cell types (small cells, granulocytes and hyalinocytes). All three herbicides caused abnormalities in cell shapes. Flow cytometric analysis of haemocytes from B. alexandrina demonstrated that circulating haemocyte populations could be divided into two main subtypes differing in their granularity (granulocytes or hyalinocytes) and size (large and small cells). In addition, the flow cytometric analysis showed that the total number of dead haemocytes in the haemolymph was significantly increased in treated groups compared to the control group. Phagocytosis in groups treated with the herbicides was highly significantly increased compared to the control indicating a very strong response of the treated snails. The results of the alkaline comet assay of DNA damage demonstrated that these herbicides have a genotoxic effect. 相似文献
7.
Yasmine Alaa El-Din Amal Hassan Abdelrahman Safa Fathy 《Biotechnic & histochemistry》2019,94(2):92-99
Salivary gland neoplasms exhibit complex histopathology in a variety of tumor types and treatment options depend largely on the stage of the cancer. Induced pluripotent stem cells (iPS) have been investigated for treating induced salivary gland cancer and for restoring salivary gland function. We investigated iPS treatment for salivary gland cancer both in vitro and in vivo. For our study in vitro, we re-programmed human skin fibroblasts to form iPS cells using a plasmid containing Oct4, Sox2, L-MYC and LIN28. For our study in vivo, we used 30 white male albino rats divided into the following groups of 10: group 1 (control): rats were injected with phosphate-buffered saline (PBS), group 2 induced squamous cell carcinoma (SCC): rat submandibular glands were injected with squamous carcinoma cells (SCC), group 3 (induced SCC/iPS): SCC treated rats treated with 5 × 106 iPS cells. Submandibular glands from rats of all groups were examined histologically and real time PCR was performed for amylase, and COX I and COX II gene expression. We confirmed that submandibular gland specimens included tumor tissue before starting treatment with iPS. iPS treated cases exhibited regeneration of salivary glands, although minor degenerative and vascularization changes remained. The acinar cells regained their proper organization, but continued to exhibit abnormal activity including hyperchromatism. iPS cells may be useful for treating salivary gland carcinomas. 相似文献
8.
Nashwa Fathy Gamal El-Tahawy Samah Mohammed Mahmoud Abozaid 《Journal of cellular physiology》2019,234(9):15487-15495
The adrenal gland is an important endocrine gland in the body that secrets the adrenal hormones. One of the important clinical issues is the hepatic ischemia–reperfusion (IR) injury. Liver IR injury results in many distant organs dysfunctions such as lung, kidney, intestine, pancreas, and myocardium. The aim of the present study was to investigate the possible remote effects of hepatic IR on the structure of the adrenal cortex. Twenty healthy males, Sprague–Dawley albino rats aged 6–8 weeks were randomly divided into two groups (10 rats each): the sham control group (SC-group) and the ischemia–reperfusion group (IR-group). Sera were estimated for the following: aspartate transaminase (AST), alanine transaminase (ALT), lactic dehydrogenase (LDH), and corticosterone levels. Also oxidative markers such as malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α), and the antioxidative enzyme, catalase were measured. Adrenal glands were processed for light and transmission electron microscopic study. The results showed a significant increase in serum liver enzymes (AST, ALT, and LDH), corticosterone, MDA, and TNF-α levels and a significant decrease in serum levels of catalase in IR-group compared with SC-group. Adrenal cortical tissue of IR-group showed the loss of normal appearance. Some cells of zona glomerulosa and most of the zona fasciculata cells appeared swollen and degenerated with highly vacuolated cytoplasm. Other cells were shrunken with deeply acidophilic cytoplasm and pyknotic nuclei. Degenerated mitochondria with disrupted cristae, lipid droplets were confluent and dilated smooth endoplasmic reticulum were seen. Few zona reticularis cells had the dark nucleus and cytoplasmic vacuolations. In the different zones, blood capillaries were markedly congested and some inflammatory cells infiltrations were observed. Liver IR affected the structure of the adrenal cortex. 相似文献
9.
Diaaeldin M. Elimam Abdullah A. Elgazar Fardous F. El-Senduny Ramadan A. El-Domany Farid A Badria Wagdy M. Eldehna 《Journal of enzyme inhibition and medicinal chemistry》2022,37(1):39
In this work, the natural piperine moiety was utilised to develop two sets of piperine-based amides (5a–i) and ureas (8a–y) as potential anticancer agents. The anticancer action was assessed against triple negative breast cancer (TNBC) MDA-MB-231, ovarian A2780CP and hepatocellular HepG2 cancer cell lines. In particular, 8q stood out as the most potent anti-proliferative analogue against TNBC MDA-MB-231 cells with IC50 equals 18.7 µM, which is better than that of piperine (IC50 = 47.8 µM) and 5-FU (IC50 = 38.5 µM). Furthermore, 8q was investigated for its possible mechanism of action in MDA-MB-231 cells via Annexin V-FITC apoptosis assay and cell cycle analysis. Moreover, an in-silico analysis has proposed VEGFR-2 as a probable enzymatic target for piperine-based derivatives, and then has explored the binding interactions within VEGFR-2 active site (PDB:4ASD). Finally, an in vitro VEGFR-2 inhibition assay was performed to validate the in silico findings, where 8q showed good VEGFR-2 inhibitory activity with IC50 = 231 nM. 相似文献
10.
Serry FM Kadry AA Abdelrahman AA 《Journal of industrial microbiology & biotechnology》2003,30(3):135-140
The present study aimed to isolate, select, and evaluate bacterial isolates with potential for use as biological indicators
for sterilization with glutaraldehyde and/or formaldehyde. A total of 340 local Bacillus isolates were screened for glutaraldehyde and/or formaldehyde resistance by determination of minimum inhibitory concentrations
(MICs), minimum bactericidal concentrations (MBCs), and extinction time and were compared with B. subtilis (var. niger) ATCC 9372, the biological indicator for ethylene oxide sterilization, as reference. Of these, 85 isolates had glutaraldehyde
MICs of 0.5% or higher, while 29 had formaldehyde MICs of 0.04% or higher. Of the 29 resistant isolates, 15 had MBCs of 0.05%
or more. Extinction times were used to evaluate the bactericidal/sporicidal activity of glutaraldehyde. Eight had inactivation
times of more than 5 h in 2% glutaraldehyde (pH 8), whereas 12 had inactivation times of more than 3 h in l% formaldehyde,
with one isolate in common. These 19 isolates were selected and evaluated as potential biological indicators for aldehydes
by determination of the decimal reduction times (D values), compared with the reference strain. Eight glutaraldehyde-resistant isolates exhibited D values 2.0- to 3.5-fold higher than the reference strain (30 min.). Only five of 12 formaldehyde resistant isolates had D values higher than that of the reference strain. Using six resistant isolates, temperature coefficient values between 2.11 and
3.02 were obtained for 2% formaldehyde. Finally, 14 isolates were tested for potential pathogenicity and were identified to
species level. All of the eight glutaraldehyde-resistant isolates, including the isolate with dual resistance, and three formaldehyde-resistant
isolates were B. licheniformis, while two other formaldehyde-resistant isolates were B. cereus. Six of the selected B. licheniformis isolates are potential biological indicators for sterilization processes using aldehydes. Three can be suggested for glutaraldehyde
only and three for both aldehydes.
Electronic Publication 相似文献