Haemolymph ecdysteroids in the solitary and gregarious larvae of Schistocerca gregaria

In the penultimate and last instar larvae of Schistocerca gregaria, 20-hydroxyecdysone (20E) makes up 74–84% of detected ecdysteroids in the females, and 63–74% in the males. Remaining ecdysteroids include ecdysone, a compound with HPLC and TLC retention times of makisterone A, and highly polar metabolites. Except for the last instar females, the contents of ecdysone and the unknown compound are higher in the solitary phase, while that of polar metabolites is higher in the gregarious phase. The phases also differ in that the molt-inducing ecdysteroid peaks last longer in the gregarious than in the solitary larvae. Peak concentrations reach 3.0–4.0 μg 20E equiv./ml in penultimate female instar, 2.5–3.0 μg/ml in penultimate male instar, and 1.5–2.0 μg/ml in the last larval instar of both sexes. © 1996 Wiley-Liss, Inc.     

Efficacy of intra-lesional glucantime in the treatment of zoonotic cutaneous leishmaniasis in basic health care conditions

A randomized placebo-controlled trial treating cutaneous lesions due to Leishmania major with intralesionnel glucantime, was conducted in El Guettar between december 1994 and June 1995, in order to assess efficacy of this therapy under field conditions. It included 109 patients: 52 were administrated glucantime and 57 received local treatment (eosin 5% and alcohol 95%). Prognostic factors were similar in both groups. Results did not reveal a significant difference between glucantime and eosin regarding the rapidity of the healing of lesions. However, scars seem to be of better quality among the glucantime group. Bacterial super infection was noticed among 57.6% of humid lesions sampled among 33 patients. Isolated strains included group A streptococcus (22%), staphylococcus aureus (16.7%) or an association of both agents (61.1%). Resistance profile indicated that streptococcus and staphylococcus respond well to macrolids compared to other antibiotic groups.     

Evaluation of the mycological status of luncheon meat with special reference to aflatoxigenic moulds and aflatoxin residues

The luncheon meat samples analyzed, which were produced locally by the two main luncheon meat producing companies in Egypt were relatively highly contaminated either by moulds and yeasts in general, aflatoxigenic species and aflatoxin residues in particular. The most frequently encountered fungi from the samples were yeasts, Aspergillus niger, A. flavus, Penicillium chrysogenum, Rhizopus stolonifer, Mucor circinelloides. Less common were Cladosporium sphaerospermum, Alternaria alternata, Mycosphaerella tassiana, P. aurantiogriseum and P. oxalicum. The most important aflatoxigenic species, A. flavus, was isolated frequently. It was 10% of the total fungal isolates from both samples of the two companies. Seven luncheon meat samples out of 50 analyzed were positive for aflatoxin B₁ or B₁ and G₁, while all samples were negative for aflatoxins B₂, G₂, M₁ and M₂. Aflatoxin B₁ was detected only in 4 and 3 samples out of 25 analyzed from each of company A and B, respectively. The highest detectable level, 11.1 ppb, was recorded in a sample from company B and the least, 0.5 ppb, in a sample from company A. Aflatoxin G₁, at concentration of 3.2 ppb, was detected in only one sample of the aflatoxin B₁ – contaminated 3 samples of company B: this sample also had the highest level of aflatoxin B₁. Some luncheon meat samples had higher numbers of aflatoxigenic A. flavus than others, however these samples were negative for aflatoxins. The hazardous potential of such contamination will be discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Involvement of Ca2+ channels in endothelin-1-induced MAP kinase phosphorylation, myosin light chain phosphorylation and contraction in rabbit iris sphincter smooth muscle

The purpose of the present study was to investigate the role and type of Ca2+ channels involved in the stimulatory effects of endothelin-1 (ET-1) on the Ca2+-dependent functional responses, p42/p44 MAP kinase phosphorylation, 20-kDa myosin light chain (MLC) phosphorylation and contraction, in rabbit iris sphincter, a nonvascular smooth muscle. ET-1 induced inositol phosphates production, MAP kinase phosphorylation, MLC phosphorylation (MLC20-P plus MLC20-2P) and contraction in a concentration-dependent manner with EC50 values of 71, 8, 6 and 25 nM, respectively. ET-1-induced MAP kinase phosphorylation, MLC phosphorylation and contraction were not significantly affected by nifedipine (1-60 microM), an L-type Ca2+ channel blocker, or by LOE 908 (1-100 microM), a blocker of Ca2+-permeable nonselective cation channels. However, SKF96365, a receptor-operated Ca2+ channel (ROCC) blocker, inhibited MAP kinase phosphorylation, MLC phosphorylation and contraction in a concentration-dependent manner with IC50 values of 28, 30 and 42 microM, respectively. 2-APB, a store-operated Ca2+ channel (SOCC) blocker, inhibited ET-1-induced MLC phosphorylation and contraction in a concentration-dependent manner with IC50 values of 12.7 and 19 microM, respectively, but was without effect on MAP kinase phosphorylation. The combined effects of submaximal concentrations of SKF96365 and 2-APB on ET-1-induced MLC phosphorylation and contraction were not additive, implying that their inhibitory actions could be mediated through a common Ca2+ entry channel. PD98059, a MAP kinase inhibitor, had no effect on ET-1-induced MLC phosphorylation and contraction, suggesting that these ET-1 effects in the rabbit iris muscle are MAP kinase-independent. In conclusion, the present study demonstrated for the first time that in rabbit iris sphincter (a) ET-1, through the ETA receptor, stimulates MAP kinase phosphorylation, MLC phosphorylation and contraction in a concentration-dependent manner, (b) that these Ca2+-dependent functional responses are not significantly affected by nifedipine or LOE908, and (c) that ET-1-induced MLC phosphorylation and contraction are inhibited by SKF96365 and 2-APB, suggesting that these effects are mainly due to store- and/or receptor Ca2+ entry.     

The effects of n-3 polyunsaturated fatty acids by gavage on some metabolic enzymes of rat liver

In this experimental study, the effect of fish n-3 fatty acids was studied on the some important enzymes of carbohydrate metabolism, hexokinase (HK), glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH) in rat liver. Wistar albino rats of experimental group (n= 9) were supplemented fish omega-3 fatty acids (n-3 PUFA) as 0.4 g/kg bw. by gavage for 30 days in addition to their normal diet. Isotonic solution was given to the control group (n= 8) by the same way. At 30th day, the rats were killed by decapitation under ether anesthesia, autopsied and liver was removed. Spectrophotometric methods were used to determine the activities of above-mentioned enzymes in the liver. The n-3 PUFA caused increases in the activities of HK, G6PD, LDH, and MDH in comparison with control. These increases were statistically significant (P < 0.01) except 6PGD activity. As a result, n-3 PUFA may regulate the metabolic function of liver effectively by increasing HK, G6PD, 6PGD, LDH, and MDH enzyme activities of rat liver when added in enough amounts to the regular diet.     

Effects of a GnRH agonist on oocyte number and maturation in mice superovulated with eCG and hCG

The objective was to investigate the effects of a gonadotropin-releasing hormone agonist (GnRH) on ovulation rate and the number and maturation of oocytes in mice superovulated with equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). Thirty 3-month-old BALB/C female mice (weight: 25-30 g) were assigned to three experimental groups: control, superovulated, and superovulated with GnRH pretreatment (n=10 per group). Control mice received an i.p. injection of 0.1 ml physiological saline solution. Superovulation was induced with 5 IU eCG (i.p.) and 5 IU hCG 48 h later. Mice in the superovulated with GnRH pretreatment group were given GnRH (20 mg/kg Fertirelin, i.m.), 24 h before superovulation. Thirteen hours after hCG administration, mice were sacrificed by cervical dislocation and blood samples were collected to determine serum progesterone concentration (by radioimmunoassay). Ovaries and oviducts were also harvested to enumerate corpora lutea and cumulus-enclosed oocytes. Progesterone concentrations were not significantly different among groups. The oocyte number and the maturation, ovulation rate, and the number of corpora lutea were higher in GnRH-treated mice than both controls and superovulated mice. In conclusion, GnRH given 24 h before superovulation with eCG-hCG increased the number and maturation of oocytes and the rate of ovulation in mice.     

Molecular study on cloned endoglucanase gene from rumen bacterium

An endoglucanase gene was subcloned from anaerobic rumen bacterium Ruminococcus flavefaciens strain 17. To express endoglucanase gene in Escherichia coli and Streptococcus bovis JB1, an endoglucanase gene fragment was inserted into pVA838-based shuttle vectors. Removal of endoglucanase gene promoter and expression of endoglucanase by promoter of S. bovis JB1 alpha-amylase gene (pACMCS) was also achieved. Survival of constructs pVACMCI, pTACMC and pACMCS, which carry endoglucanase gene, and stability of endoglucanase gene in S. bovis JB1, were observed. Maximal endoglucanase activities from S. bovis JB1/pVACMCI were 2- to 3-fold higher than from E. coli/pVACMCI. Specific cell activity of E. coli/pACMCS was found to be approximately 2- to -3 fold higher than the both E. coli/pVACMCI and E. coli/pTACMC. Specific cell activity of S. bovis JB1/pACMCS was also found to be approximately 2-fold higher than the both S. bovis/pVACMCI and S. bovis JB1/pTACMC.     

Synthesis and immunomodulatory properties of selected oxazolone derivatives

Eleven oxazolone derivatives were synthesized and characterized by (1)H NMR, EI, IR and UV spectroscopic and CHN analysis. Three compounds, 4-[(E)-(4-nitrophenyl)methylidene]-2-phenyl-1,3-oxazol-5(4H)-one (11), 4-[(E)-(4-methoxyphenyl)methylidene]-2-methyl-1,3-oxazol-5-one (12) and 4-[(E)-(4-nitrophenyl)methylidene]-2-methyl-1,3-oxazol-5(4H)-one (13) were screened for phagocyte chemiluminescence, neutrophil chemotaxis, T-cell proliferation, cytokine production from mononuclear cells and cytotoxicity. 4-[(E)-(4-Nitrophenyl)methylidene]-2-methyl-1,3-oxazol-5(4H)-one (13) was found to be the most potent immunomodulator in the series.     

Positive and negative regulation of the gamma-secretase activity by nicastrin in a murine model

Nicastrin is a component of the gamma-secretase complex that has been shown to adhere to presenilin-1 (PS1), Notch, and APP. Here we demonstrate that Nicastrin-deficient mice showed a phenotype that is indistinguishable from PS1/PS2 double knock-out mice, whereas heterozygotes were healthy and viable. Fibroblasts derived from Nicastrin-deficient embryos were unable to generate amyloid beta-peptide and failed to release the intracellular domain of APP- or Notch1-Gal4-VP16 fusion proteins. Additionally, C- and N-terminal fragments of PS1 and the C-terminal fragments of PS2 were not detectable in Nicastrin-null fibroblasts, whereas full-length PS1 accumulated in null fibroblasts, indicating that Nicastrin is required for the endoproteolytic processing of presenilins. Interestingly, cells derived from Nicastrin heterozygotes produced relatively higher levels of amyloid beta-peptide whether the source was endogenous mouse or transfected human APP. These data demonstrate that Nicastrin is essential for the gamma-secretase cleavage of APP and Notch in mammalian cells and that Nicastrin has both positive and negative functions in the regulation of gamma-secretase activity.     

A tree-based algorithm for determining the effects of solvation on the structure of salivary gland tripeptide NH3+-D-PHE-D-GLU-GLY-COO-

A D-enantiomeric analog of the submandibular gland rat-1 tripeptide FEG (Seq: NH(3)(+)-Phe-Glu-Gly-COO(-)) called feG (Seq: NH(3)(+)-D-Phe-D-Glu-Gly-COO(-)) was examined by molecular dynamics simulations in water. Previous in vacuo simulations suggested a conformation consisting predominantly of interactions between the Phe side chain and glutamyl-carboxyl group and a carboxyl/amino termini interaction. The solvated peptide was simulated using two approaches which were compared-a single 400-ns simulation and a "simulation tree." The "tree" approach utilized 45 10-ns simulations with different conformations used as initial structures for given trajectories. We demonstrate that multiple short duration simulations are able to describe the same conformational space as that described by longer simulations. Furthermore, previously described in vacuo interactions were confirmed with amendments: the previously described head-to-tail arrangement of the amino and carboxyl termini, was not observed; the interaction between the glutamyl carboxyl and Phe side chain describes only one of a continuum of conformations present wherein the aromatic residue remains in close proximity to the glutamyl carbonyl group, and also interacts with either of the two available carboxyl groups. Finally, utilizing only two separate 10-ns trajectories, we were able to better describe the conformational space than a single 60-ns trajectory, realizing a threefold decrease in the computational complexity of the problem.