Eimeria pavoaegyptica sp. nov. (Apicomplexa: Eimeriidae) in faeces of Indian peacocks, Pavo cristatus Linnaeus, 1758 (Galliformes: Phasianidae) from Egypt

Coprological examination of 15 Indian peacocks, Pavo cristatus, revealed the presence of a coccidium species of the genus Eimeria, which apparently represents a previously undescribed species. Sporulation is exogenous and fully developed oocysts of Eimeria pavoaegyptica sp. nov. are ellipsoidal, with a dimension of 15 (13-16) × 12 (10-12.9) microm and with a shape index of 1.25 (1-1.3). The sporulated oocysts have no micropyle but enclose one large rectangular-shaped polar granule and an oocyst residuum. The oocysts have a distinct two-layered wall, which is ~approximately1.7 microm thick. The outer layer has a smooth texture; it fills ~? of the total thickness and appears bicolored. The sporocysts are boat-shaped, of about 10 (9-11) × 4 (4-4.7) microm; their average shape-index is 2.5 microm with a small pointed Stieda body and a smooth, thin single-layered wall. No substieda body is detected. The sporocysts contain numerous, nearly uniform granular residua. The sporozoites are banana-shaped, 6 × 3 microm and each has two different-sized refractile bodies.     

Myristate exposure in the human immunodeficiency virus type 1 matrix protein is modulated by pH

Human immunodeficiency virus type 1 (HIV-1) encodes a polypeptide called Gag that is capable of forming virus-like particles (VLPs) in vitro in the absence of other cellular or viral constituents. During the late phase of HIV-1 infection, Gag polyproteins are transported to the plasma membrane (PM) for assembly. A combination of in vivo, in vitro, and structural studies have shown that Gag targeting and assembly on the PM are mediated by specific interactions between the myristoylated matrix [myr(+)MA] domain of Gag and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Exposure of the MA myristyl (myr) group is triggered by PI(4,5)P2 binding and is enhanced by factors that promote protein self-association. In the studies reported here, we demonstrate that myr exposure in MA is modulated by pH. Our data show that deprotonation of the His89 imidazole ring in myr(+)MA destabilizes the salt bridge formed between His89(Hδ2) and Glu12(COO-), leading to tight sequestration of the myr group and a shift in the equilibrium from trimer to monomer. Furthermore, we show that oligomerization of a Gag-like construct containing matrix-capsid is also pH-dependent. Disruption of the His?Glu salt bridge by single-amino acid substitutions greatly altered the myr-sequestered?myr-exposed equilibrium. In vivo intracellular localization data revealed that the H89G mutation retargets Gag to intracellular compartments and severely inhibits virus production. Our findings reveal that the MA domain acts as a “pH sensor” in vitro, suggesting that the effect of pH on HIV-1 Gag targeting and binding to the PM warrants investigation.     

The anti-myeloma activity of a novel purine scaffold HSP90 inhibitor PU-H71 is via inhibition of both HSP90A and HSP90B1

Background

The ribonucleotide reductase M1 (RRM1) gene encodes the regulatory subunit of ribonucleotide reductase, the molecular target of gemcitabine. The overexpression of RRM1 mRNA in tumor tissues is reported to be associated with gemcitabine resistance. Thus, single nucleotide polymorphisms (SNPs) of the RRM1 gene are potential biomarkers of the response to gemcitabine chemotherapy. We investigated whether RRM1 expression in peripheral blood mononuclear cells (PBMCs) or SNPs were associated with clinical outcome after gemcitabine-based chemotherapy in advanced non-small cell lung cancer (NSCLC) patients.

Methods

PBMC samples were obtained from 62 stage IIIB and IV patients treated with gemcitabine-based chemotherapy. RRM1 mRNA expression levels were assessed by real-time PCR. Three RRM1 SNPs, -37C→A, 2455A→G and 2464G→A, were assessed by direct sequencing.

Results

RRM1 expression was detectable in 57 PBMC samples, and SNPs were sequenced in 56 samples. The overall response rate to gemcitabine was 18%; there was no significant association between RRM1 mRNA expression and response rate (P = 0.560). The median progression-free survival (PFS) was 23.3 weeks in the lower expression group and 26.9 weeks in the higher expression group (P = 0.659). For the -37C→A polymorphism, the median PFS was 30.7 weeks in the C(-)37A group, 24.7 weeks in the A(-)37A group, and 23.3 weeks in the C(-)37C group (P = 0.043). No significant difference in PFS was observed for the SNP 2455A→G or 2464G→A.

Conclusions

The RRM1 polymorphism -37C→A correlated with PFS in NSCLC patients treated with gemcitabine-based chemotherapy. No significant correlation was found between PBMC RRM1 mRNA expression and the efficacy of gemcitabine.     

Semisynthesis and in vitro anticancer activities of andrographolide analogues

The plant Andrographis paniculata found throughout Southeast Asia contains Andrographolide 1, a diterpenoid lactone, which has antitumour activities against in vitro and in vivo breast cancer models. In the present study, we report on the synthesis of andrographolide derivatives, 3,19-isopropylideneandrographolide (2), 14-acetyl-3,19-isopropylideneandrographolide (3) and 14-acetylandrographolide (4), and their in vitro antitumour activities against a 2-cell line panel consisting of MCF-7 (breast cancer cell line) and HCT-116 (colon cancer cell line). Compounds 2 and 4 were also screened at the US National Cancer Institute (NCI) for their activities against a panel of 60 human cancer cell lines derived from nine cancer types. Compound 2 was found to be selective towards leukaemia and colon cancer cells, and compound 4 was selective towards leukaemia, ovarian and renal cancer cells at all the dose-response parameters. Compounds 2 and 4 showed non-specific phase of the cell cycle arrest in MCF-7 cells treated at different intervals with different concentrations. NCI's COMPARE and SOM mechanistic analyses indicated that the anticancer activities of these new class of compounds were not similar to that of standard anticancer agents, suggesting novel mechanism(s) of action.     

Point mutations in the HIV-1 matrix protein turn off the myristyl switch

During the late phase of human immunodeficiency virus type-1 (HIV-1) replication, newly synthesized retroviral Gag proteins are targeted to lipid raft regions of specific cellular membranes, where they assemble and bud to form new virus particles. Gag binds preferentially to the plasma membrane (PM) of most hematopoietic cell types, a process mediated by interactions between the cellular PM marker phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P(2)) and Gag's N-terminally myristoylated matrix (MA) domain. We recently demonstrated that PI(4,5)P(2) binds to a conserved cleft on MA and promotes myristate exposure, suggesting a role as both a direct membrane anchor and myristyl switch trigger. Here we show that PI(4,5)P(2) is also capable of binding to MA proteins containing point mutations that inhibit membrane binding in vitro, and in vivo, including V7R, L8A and L8I. However, these mutants do not exhibit PI(4,5)P(2) or concentration-dependent myristate exposure. NMR studies of V7R and L8A MA reveal minor structural changes that appear to be responsible for stabilizing the myristate-sequestered (myr(s)) species and inhibiting exposure. Unexpectedly, the myristyl group of a revertant mutant with normal PM targeting properties (V7R,L21K) is also tightly sequestered and insensitive to PI(4,5)P(2) binding. This mutant binds PI(4,5)P(2) with twofold higher affinity compared with the native protein, suggesting a potential compensatory mechanism for membrane binding.     

Hepatic morphological alterations,glycogen content and cytochrome P450 activities in rats treated chronically with N<Superscript>ω</Superscript>-nitro-L-arginine methyl ester (L-NAME)

Chronic treatment of rats with N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) biosynthesis, results in hypertension mediated partly by enhanced angiotensin-I-converting enzyme (ACE) activity. We examined the influence of L-NAME on rat liver morphology, on hepatic glycogen, cholesterol, and triglyceride content, and on the activities of the cytochrome P450 isoforms CYP1A1/2, CYP2B1/2, CYP2C11, and CYP2E1. Male Wistar rats were treated with L-NAME (20 mg/rat per day via drinking water) for 2, 4, and 8 weeks, and their livers were then removed for analysis. Enzymatic induction was produced by treating rats with phenobarbital (to induce CYP2B1/2), beta-naphthoflavone (to induce CYP1A1/2), or pyrazole (to induce CYP2E1). L-NAME significantly elevated blood pressure; this was reversed by concomitant treatment with enalapril (ACE inhibitor) or losartan (angiotensin II AT(1) receptor antagonist). L-NAME caused vascular hypertrophy in hepatic arteries, with perivascular and interstitial fibrosis involving collagen deposition. Hepatic glycogen content also significantly increased. L-NAME did not affect fasting glucose levels but significantly reduced insulin levels and increased the insulin sensitivity of rats, based on an intraperitoneal glucose tolerance test. Immunoblotting experiments indicated enhanced phosphorylation of protein kinase B and of glycogen synthase kinase 3. All these changes were reversed by concomitant treatment with enalapril or losartan. L-NAME had no effect on hepatic cholesterol or triglyceride content or on the basal or drug-induced activities and protein expression of the cytochrome P450 isoforms. Thus, the chronic inhibition of NO biosynthesis produced hepatic morphological alterations and changes in glycogen metabolism mediated by the renin-angiotensin system. The increase in hepatic glycogen content probably resulted from enhanced glycogen synthase activity following the inhibition of glycogen synthase kinase 3 by phosphorylation.     

The interdependence of EGF-R and SGK-1 in fibronectin expression in primary kidney cortical fibroblast cells

BACKGROUND: Epidermal growth factor (EGF) has been shown to play a role in the nephromegaly and enhanced sodium reabsorption observed in diabetic nephropathy. This is recognized to be dependent on activation of serine threonine glucocorticoid kinase-1 (SGK-1). However, the roles of EGF and SGK-1 in renal fibrogenesis observed under high glucose conditions have not been established. METHODS: Primary cultures of human cortical fibroblasts (CFs) were used as the model in which to study the dependent and independent effects of high glucose, EGF and SGK-1 on the expression of the extracellular matrix protein (ECM) fibronectin. Wild type CFs expressing SGK-1, or cells in which SGK-1 was effectively silenced using siRNA methodology, were exposed to normal (5mM) or high (25mM) glucose, or EGF (10ng/ml) for 48hr and fibronectin assessed. The role of the EGF-receptor and its relationship to SGK-1 signaling was studied using concurrent treatment with PKI166, a specific inhibitor of EGF-receptor. RESULTS: Exposure of CF to high glucose and EGF increased phosphorylated EGF-R, SGK-1, and fibronectin expression in wild-type cells. Inhibition of the EGF-R reduced SGK-1 and fibronectin expression in control, and following exposure to EGF and high glucose conditions. In cells in which SGK-1 was silenced, fibronectin was reduced and there was no significant increase in pEGF-R, suggesting that SGK-1 is downstream of the EGF-R and negatively inhibits EGF-R activation. CONCLUSION: These results suggest that high glucose induced fibronectin expression is mediated through the EGF-R and downstream expression of SGK-1.     

Biological performance of quercetin on the cotton leaf-worm larvae, Spodoptera littoralis Boisd. (Lep., Noctuidae) and prevailing natural enemies in the Egyptian cotton fields

The Egyptian cotton (Gossypium barbadense L.) accounts for 65 % of the world production of long stable cultivars. Taking into consideration the competition of other cotton producing countries, it should be of great importance to control pests, which attack the cotton plants to improve the yield and its quality. The main objective of this study is to develop new approaches for the management of the cotton leafworm Spodoptera littoralis Boisd. within an IPM program, that include synthetic insecticides rationalization, and maximiziation the role of the biological control agents. Sunflower plants Helianthus annuus (Asterales: Asteraceae) raised in rows surrounding plots of cotton were used as trap plants to attract some biological agents, which subsequently lead to check the build-up of the cotton leafworm population. This scientific phenomenon was attributed to the main chemical constituent of sunflower plants, which has been proved to be the polyhydroxy flavone "quercetin". Field data of the two successive seasons 2004 and 2005 revealed that: (a) the total number of insect predators, Coccinella undecimpunctata, Paederus alfierli, Chrysopa vulgaris, Orius laevigatus, Scymnus synacus, and true spiders in the cotton plots surrounded by either one or two rows of sunflower plants significantly exceeded the corresponding numbers in the cotton plots without sunflower plants., (b) the least number of cotton leafworm Spodoptera littorolis larvae infestation was recorded simultaneously in the cotton plots surrounded by sunflower plants. Moreover, laboratory studies assured the antifeeding properties of quercetin against the 4th instar larvae of Spodoptera littoralis. Quercetin at a concentration rate of 4000 ppm, showed abnormal behaviour represented in feeding stop, growth inhibition and development retardation. Deformation of pupae, moths, and reduction up to 50% in egg laying was also noticed after quercetin application to the larvae.