Effect of propolis extract on acute carbon tetrachloride induced hepatotoxicity

Ethanolic extract of propolis was administered to rats intoxicated by carbon tetrachloride. Administration of bolus dose of CCl4 (1.5 ml/kg, ip) resulted in elevation of serum transaminases and serum alkaline phosphatase activities. Levels of hepatic lipid peroxidation were significantly increased. On the contrary, there was significant decrease in hepatic reduced glutathione level. The propolis extract (100 and 200 mg/kg, po) exhibited recoupment in both pre- and post-treatment (prophylactic and curative studies) of biochemical changes induced by CCl4. The post treatment of 200 mg/kg, po extract showed most significant hepatoprotective effect. Histopathological studies showed damage in hepatocytes and disturbed chord arrangement after toxicant administration. Propolis extract (200 mg/kg, po) was found to be more effective in restoring CCl4 induced histopathological alterations.     

EphA2 Mutation in Lung Squamous Cell Carcinoma Promotes Increased Cell Survival,Cell Invasion,Focal Adhesions,and Mammalian Target of Rapamycin Activation

Non-small cell lung cancer (NSCLC) has a poor prognosis and improved therapies are needed. Expression of EphA2 is increased in NSCLC metastases. In this study, we investigated EphA2 mutations in NSCLC and examined molecular pathways involved in NSCLC. Tumor and cell line DNA was sequenced. One EphA2 mutation was modeled by expression in BEAS2B cells, and functional and biochemical studies were conducted. A G391R mutation was detected in H2170 and 2/28 squamous cell carcinoma patient samples. EphA2 G391R caused constitutive activation of EphA2 with increased phosphorylation of Src, cortactin, and p130^Cas. Wild-type (WT) and G391R cells had 20 and 40% increased invasiveness; this was attenuated with knockdown of Src, cortactin, or p130^Cas. WT and G391R cells demonstrated a 70% increase in focal adhesion area. Mammalian target of rapamycin (mTOR) phosphorylation was increased in G391R cells with increased survival (55%) compared with WT (30%) and had increased sensitivity to rapamycin. A recurrent EphA2 mutation is present in lung squamous cell carcinoma and increases tumor invasion and survival through activation of focal adhesions and actin cytoskeletal regulatory proteins as well as mTOR. Further study of EphA2 as a therapeutic target is warranted.     

Siderophore Cross-Utilization Amongst Rhizospheric Bacteria and the Role of Their Differential Affinities for Fe3+ on Growth Stimulation Under Iron-Limited Conditions

The majority of bacteria isolated from rhizospheres of Arachis hypogea (Groundnut) and Vigna radiata (Mung bean) predominantly produced catechol-type siderophores except for a few fluorescent pseudomonads that produced hydroxamates in addition to catecholates. The rhizospheric isolates differed in their ability to cross-utilize siderophores produced by other rhizospheric isolates (heterologous); some were highly proficient at utilizing heterologous siderophores, while others were poor cross-utilizers. Isolate G9, which utilized hydroxamate as well as catecholate siderophores, was found to be an efficient siderophore cross-utilizer, while isolates G2 and G6 were poor-utilizers of catecholate and non-utilizers of hydroxamate siderophores. Growth stimulation of two isolates G9 and G6 was seen when grown in the presence of externally supplied heterologous siderophores, which they cross-utilized. The iron-regulated outer membrane protein (IROMP) profiles differed for the most cross-utilizer and the least cross-utilizer strains, but in both the cases no new outer membrane proteins (OMP) were induced in response to the exogenous siderophores supplied. The growth of the organisms in the presence of heterologous siderophores that they failed to cross-utilize led to growth inhibition in the case of isolate G9. This appears to be due to a lower affinity of the siderophore of G9 as compared to the exogenously supplied G6 siderophore. A simple method was devised to measure relative affinities of respective siderophores for iron based on CAS solution decolorization by the siderophore preparations. The effect on the growth of the differential affinities of the siderophores for iron and the interactions of the organisms through cross-utilization is also discussed.     

Specific PCR-based detection of Alternaria helianthi: the cause of blight and leaf spot in sunflower

Alternaria helianthi is an important seed-borne pathogenic fungus responsible for blight disease in sunflower. The current detection methods, which are based on culture and morphological identification, are time-consuming, laborious and are not always reliable. A PCR-based diagnostic method was developed with species-specific primers designed based on the sequence data of a region consisting of the 5.8S RNA gene and internal transcribed spacers—ITS 1 and ITS 2 of nuclear ribosomal RNA gene (rDNA) repeats of A. helianthi. The specificity of the primer pairs AhN1F and AhN1R designed was verified by PCR analysis of DNA from 18 Alternaria helianthi strains isolated from India, 14 non-target Alternaria spp. and 11 fungal isolates of other genera. A single amplification product of 357-bp was detected from DNA of A. helianthi isolates. No cross-reaction was observed with any of the other isolates tested. The detection limit of the PCR method was of 10?pg from template DNA. The primers could also detect the pathogen in infected sunflower seed. This species-specific PCR method provides a quick, simple, powerful and reliable alternative to conventional methods in the detection and identification of A. helianthi. This is the first report of an A. helianthi-specific primer set.     

Low pH induced structural reorganization in thylakoid membranes

By using low temperature fluorescence spectroscopy, it has been shown that exposing chloroplast thylakoid membranes to acidic pH reversibly decreases the fluorescence of photosystem II while the fluorescence of photosystem I increases [P. Singh-Rawal et al. (2010) Evidence that pH can drive state transitions in isolated thylakoid membranes from spinach, Photochem Photobiol Sci, 9 830-837]. In order to shed light on the origin of these changes, we performed circular dichroism (CD) spectroscopy on freshly isolated pea thylakoid membranes. We show that the magnitude of the psi-type CD, which is associated with the presence of chirally ordered macroarrays of the chromophores in intact thylakoid membranes, decreases gradually and reversibly upon gradually lowering the pH of the medium from 7.5 to 4.5 (psi, polymer or salt induced). The same treatment, as shown on thylakoid membranes washed in hypotonic low salt medium possessing no psi-type bands, induces no discernible change in the excitonic CD. These data show that while no change in the pigment-pigment interactions and thus in the molecular organization of the bulk protein complexes can be held responsible for the observed changes in the fluorescence, acidification of the medium significantly alters the macro-organization of the complexes, hence providing an explanation for the pH-induced redistribution of the excitation energy between the two photosystems. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.     

The Escherichia coli SMC Complex, MukBEF, Shapes Nucleoid Organization Independently of DNA Replication

SMC (structural maintenance of chromosomes) complexes function ubiquitously in organizing and maintaining chromosomes. Functional fluorescent derivatives of the Escherichia coli SMC complex, MukBEF, form foci that associate with the replication origin region (ori). MukBEF impairment results in mispositioning of ori and other loci in steady-state cells. These observations led to an earlier proposal that MukBEF positions new replicated sister oris. We show here that MukBEF generates and maintains the cellular positioning of chromosome loci independently of DNA replication. Rapid impairment of MukBEF function by depleting a Muk component in the absence of DNA replication leads to loss of MukBEF foci as well as mispositioning of ori and other loci, while rapid Muk synthesis leads to rapid MukBEF focus formation but slow restoration of normal chromosomal locus positioning.     

Design,synthesis and antimicrobial evaluation of novel 1-benzyl 2-butyl-4-chloroimidazole embodied 4-azafluorenones via molecular hybridization approach

A series of novel 1-benzyl-2-butyl-4-chloroimidazole embodied 4-azafluorenone hybrids, designed via molecular hybridization approach, were synthesized in very good yields using one pot condensation of 1-benzyl-2-butyl-4-chloroimidazole-5-carboxaldehyde, 1,3-indanedione, aryl/heteroaryl methyl ketones and ammonium acetate. All the synthetic derivatives were fully characterized by spectral data and evaluated for antimicrobial activity by disc diffusion method against selected bacteria and fungal strains. Among the 15 new compounds screened, 4-(1-benzyl-2-butyl-4-chloro-1H-imidazol-5-yl)-2-(furan-2-yl)-5H-indeno[1,2-b]pyridin-5-one(10k) has pronounced activity with higher zone of inhibition (ZoI) against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Aspergillus flavus and Candida albicans. Also 4-(1-benzyl-2-butyl-4-chloro-1H-imidazol-5-yl)-2-(dibenzo[b,d]thiophen-2-yl)-5H-indeno [1,2-b]pyridin-5-one (10n) and 4-(1-benzyl-2-butyl-4-chloro-1H-imidazol-5-yl)-2-(3-tosyl-3H-inden-1-yl)-5H-indeno[1,2-b]pyridin-5-one (10o) showed selective higher inhibitory activity against Aspergillus flavus and Candida albicans. The results demonstrated potential importance of molecular hybridization in the development of 10k as potential antimicrobial agent.     

Alternaria-Induced Release of IL-18 from Damaged Airway Epithelial Cells: An NF-κB Dependent Mechanism of Th2 Differentiation?

Background

A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epithelium-derived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation.

Methodology/Principal Finding

We used ELISA to measure human and mouse cytokines. Alternaria extract (ALT-E) induced rapid release of IL-18, but not IL-4, IL-9, IL-13, IL-25, IL-33, or TSLP from cultured normal human bronchial epithelial cells; and in the BAL fluids of naïve mice after challenge with ALT-E. Both microscopic and FACS indicated that this release was associated with necrosis of epithelial cells. ALT-E induced much greater IL-18 release compared to 19 major outdoor allergens. Culture of naïve CD4 cells with rmIL-18 induced Th2 differentiation in the absence of IL-4 and STAT6, and this effect was abrogated by disrupting NF- κB p50 or with a NEMO binding peptide inhibitor.

Conclusion/Significance

Rapid and specific release of IL-18 from Alternaria-exposed damaged airway epithelial cells can directly initiate Th2 differentiation of naïve CD4⁺ T-cells via a unique NF-κB dependent pathway.     

Acute Myocardial Infarction following a possible direct intravenous bite of Russell's viper (Daboia russelli)

ABSTRACT: BACKGROUND: Russell's viper (Daboia russelli) bites lead to high morbidity and mortality in South Asia. Although variety of clinical manifestations is reported in viper bite victims, myocardial ischemic events are rare. CASE PRESENTATION: We report a unique case of inferior wall ST elevation myocardial infarction due to a Russell's viper bite over a vein with possible direct intravenous envenoming, in a young male with no past history or family history suggestive of ischemic cardiac disease, from Sri Lanka. In addition, the possible mechanisms of myocardial ischemia in snake bite victims are also briefly discussed. CONCLUSION: Importance of the awareness of physicians on the rare, yet fatal manifestations of snake envenoming is highlighted.