Effects of the Phosphatase Inhibitors Calyculin A and Okadaic Acid on Acetylcholine Synthesis and Content of Rat Hippocampal Formation

Abstract: The biochemical mechanisms involved in the regulation of acetylcholine (ACh) turnover are poorly understood. In the experiments reported here, we examined whether inhibition of the serine/threonine phosphatases 1 and 2A by calyculin A or okadaic acid alters ACh synthesis by rat hippocampal preparations. With hippocampal slices, calyculin A (50 n M ) and okadaic acid (50 n M ) reduced significantly ( p < 0.01) the synthesis of [³H]ACh from [³H]choline. Both calyculin A and okadaic acid produced significant depletion of endogenous tissue ACh in a concentration-dependent manner ( p < 0.01). This depletion was not the result of a drug-induced increase of spontaneous ACh release, which was not changed significantly ( p > 0.7) by either drug. Choline acetyltransferase (ChAT) activity from tissue exposed to calyculin A or okadaic acid was reduced in a concentration-dependent manner ( p < 0.05), but these phosphatase inhibitors did not act directly on ChAT in vitro; i.e., enzymatic activity was not altered significantly ( p > 0.4) in the presence of calyculin A or okadaic acid. Both high-affinity and low-affinity [³H]choline uptake by hippocampal synaptosomes were reduced significantly in a concentration-dependent manner in the presence of calyculin A or okadaic acid; these agents reduced V _max values for high- and low-affinity choline uptake ( p < 0.01) with no significant change in K _m values ( p > 0.1), indicating a noncompetitive inhibition. Taken together, these data suggest that phosphatase activity plays a role in presynaptic central cholinergic nerve terminal function, in particular in the modulation of ACh synthesis.     

Fungal population in the atmosphere of Ismailia City

Fungal spore populations in the outdoor and indoor atmosphere of Ismailia have been studied during the period from March 1992 to May 1993. A total of 23 350 cfu and 73 species were recorded,Cladosporium cladosporioides, Aureobasidium pullulans andAspergillus flavus were the most abundant. The indoor and outdoor mycoflora showed marked quantitative and qualitative differences. In view of count, recorded species could be categorized into three groups as follows: (a) species showing higher counts in out- than indoor, (b) species showing the opposite trend i.e. lower counts in out-door than indoor, (c) species showing approximately equal counts in out- and indoor. Regarding seasonal periodicity, March and either September or October showed the highest count for both normal fungal flora (NFF) and opportunistic fungal flora (OFF). While January and July showed the lowest count of them both, May but not July was the lowest as for outdoor NFF.     

Factors affecting growth and urease production by Trichophyton spp.

Among Trichophyton spp. examined for urease production, T. rubrum was negative, whereas T. mentagrophytes appeared to be the most active species. Urease was not detected in cell-free culture fluids of the tested fungi. The endocellular urease of the test fungi was essentially constitutive. Moreover, addition of urea to the growth medium of these organisms markedly inhibited their mycelial biomass and ureolytic yield. Environmental factors showed variable effects on the test fungi and there was no correlation between mycelial growth and urease activity of these fungi.     

Enhancement of faba bean nodulation,nitrogen fixation and growth by different microorganisms

The effect of four bacterial and six fungal species on nodulation and growth ofVicia faba cv. Giza 3 inoculated withRhizobium leguminosarum biovarviceae strain RCR 1001 were assessed in a pot experiment.Bacillus cereus, Pseudomonas fluorescens, Aspergillus niger andA. quadriliniatus either alive cells or sterile filtrate significantly promoted nodulation, growth and nitrogen accumulation. Heat-killed cells had no effect.     

Factors affecting ureolytic activities ofPenicillium waksmanii isolated from sewage sludge

Twenty one fungal isolates belonging to 7 genera were screened for ureolytic activity. APenicillium waksmanii isolate was found to be the most potent and was selected for further study. No ammonia-nitrogen was detected inP. waksmanii cultures either urea-free or containing up to 1 g urea per L. The maximum extracellular urease production was recorded at a urea concentration of 15 g/L. It peaked after 6 d of incubation at 25°C when the initial pH of the glucose—peptone broth was adjusted to 6. On the other hand, the highest fungus biomass was detected at a concentration of 2 g urea per L after 4 d of incubation at 35°C when the pH of the medium was 8. The intracellular urease activity (measured in cell-free extract) was the highest at 12 mg urea per mL after 75-min incubation at 25°C at pH 8. Incubation temperature of 25°C favored both urease production and activity.     

Study of quercetin and fisetin synergistic effect on breast cancer and potentially involved signaling pathways

Naturally-derived drugs have drawn much attention in recent decades. Efficiency, lower toxicity, and economic reasons are some of their advantages that justify this broad range of administration for different diseases, including cancer. If we can find a specific combination that boosts the effects of their single therapy, leading to synergism effect, increased efficiency, and decreased toxicity, they can act even better. Quercetin and fisetin, two well-known flavonoids, have been used to fight against various cancers. In this study, we investigated their possible synergism quercetin and fisetin on MCF7, MDA-MB-231, BT549, T47D, and 4T1 breast cancer cell lines. Then the optimum combined dose was used to study their impacts on wound healing abilities and clonogenic properties. The real-time qPCR was used to study the expression of their validated downstream effectors in predicted pathways. A significant synergism effect (p < .01, combination index: <1) was observed for all cell lines. Combination therapy was significantly more effective in colony formation (p < .0001) and wound healing assays (p < .001) compared to single therapies. The expression level of potential effectors was also showed a greater change. In vivo study confirmed the in vitro results and showed how significantly (p < .001) their synergism promotes their singular function in inhibiting cancer progression. The breast cancer mouse models receiving combined therapy lived longer with higher average body weight and smaller tumor sizes. These results exhibit that quercetin and fisetin inhibit cancer cell proliferation, migration and colony formation synergistically, and matrix metalloproteinase signaling and apoptotic pathways are relatively responsible for inhibitory activities.     

Selenium in combination with a tomato lipid extract as a therapy for benign prostatic hyperplasia and its alterations in rats with induced BPH

Benign prostatic hyperplasia (BPH) is the most common adenoma in old men. Tomatoes are a rich source of bioactive compounds that, as well as selenium (Se), possess antioxidant and antiproliferative activity. The aim was to evaluate the therapeutic effect of Se in combination with a tomato extract in aged rats with BPH. Aged male Wistar rats were divided in the following groups (n = 10 rats/group): Control (C), BPH, BPH + Finasteride (BPH + F), BPH + Tomato Lipidic Extract (BPH + E), BPH + Selenium (BPH + S) and BPH plus E plus S (BPH + E + S). After 4 weeks of treatment, prostate weight, diuresis, antioxidants enzymes, prooxidants and inflammatory markers, growth factors and androgens were determined. BPH + E + S reduced prostate weight by 59.29% and inhibited growth by 99.35% compared to BPH + F which only decreased weight and inhibited growth by 15.31% and 57.54%, respectively. Prooxidant markers were higher with BPH + F (49.4% higher vs. BPH), but BPH + E + S decreased these markers (94.27% vs. BPH) and increased antioxidant activity. Finally, diuresis was higher with the BPH + E + S combination and markers of inflammation and growth factors were significantly lower with respect to BPH + F. Our findings provide a beneficial and protective therapeutic option of E + S directed against androgens, oxidative stress and inflammation that regulates cell proliferation in the prostate gland.     

Biosorption of uranium by Myxococcus xanthus

This paper deals with uranium biosorption by Myxococcus xanthus biomass in which dry biomass, accumulating up to 2.4 mM of uranium g⁻¹, is demonstrated to be a more efficient biosorbent than wet biomass. For uranium concentrations of 0.1–0.3 mM, between 95.79% and 95.99% of the uranium was taken up from the solution. Dry biomass biosorption was found to be relatively rapid, reaching equilibrium after 5–10 min. In addition, the pH influenced biosorption, pH 4.5 promoting maximum uptake. It was also established that the biosorbed uranium is located on the cellular wall and within the extracellular mucopolysaccharide of this microorganism. Furthermore, using sodium carbonate as a desorbent agent, 80.82% of the biosorbed uranium could be recovered. The results obtained indicate the possible utilization of M. xanthus biomass to solve some problems of the water contaminated by uranium.     

P-Element Insertion Alleles of Essential Genes on the Third Chromosome of Drosophila Melanogaster: Correlation of Physical and Cytogenetic Maps in Chromosomal Region 86e-87f

We have established a collection of 2460 lethal or semi-lethal mutant lines using a procedure thought to insert single P elements into vital genes on the third chromosome of Drosophila melanogaster. More than 1200 randomly selected lines were examined by in situ hybridization and 90% found to contain single insertions at sites that mark 89% of all lettered subdivisions of the Bridges' map. A set of chromosomal deficiencies that collectively uncover ~25% of the euchromatin of chromosome 3 reveal lethal mutations in 468 lines corresponding to 145 complementation groups. We undertook a detailed analysis of the cytogenetic interval 86E-87F and identified 87 P-element-induced mutations falling into 38 complementation groups, 16 of which correspond to previously known genes. Twenty-one of these 38 complementation groups have at least one allele that has a P-element insertion at a position consistent with the cytogenetics of the locus. We have rescued P elements and flanking chromosomal sequences from the 86E-87F region in 35 lines with either lethal or genetically silent P insertions, and used these as probes to identify cosmids and P1 clones from the Drosophila genome projects. This has tied together the physical and genetic maps and has linked 44 previously identified cosmid contigs into seven ``supercontigs' that span the interval. STS data for sequences flanking one side of the P-element insertions in 49 lines has identified insertions in the αγ element at 87C, two known transposable elements, and the open reading frames of seven putative single copy genes. These correspond to five known genes in this interval, and two genes identified by the homology of their predicted products to known proteins from other organisms.