Ochroconis humicola Coexisting with Esthesioneuroblastoma: An Incidental Coloniser or Allergen?

Ochroconis humicola, a fish pathogen, is rarely reported to cause disease in human. We report its first isolation from nasal tissue of a human immunodeficiency virus-positive young female patient. Histopathologically, the nasal mass was diagnosed as esthesioneuroblastoma. She presented with right-sided nasal obstruction and bleeding for two and half months. Computed tomography scan showed the nasal mass filling the whole right nasal cavity, maxillary, ethmoid and sphenoid sinuses. The direct microscopy of the nasal tissue and mucin demonstrated the presence of septate hyphae. On culture, O. humicola was isolated from the same tissue and the fungus was identified by morphologic, physiologic and molecular data including sequencing of ITS and 28S rDNA regions. No antifungal was prescribed, and the whole mass was resected out by endoscopic surgery. The patient was treated further by radical radiotherapy. After 1 year of follow-up, patient is stable with no recurrence of tumour. The role of this fungus was not clear, as it may be bystander or producing allergic fungal rhinosinusitis.     

In vitro propagation of female Ephedra foliata Boiss. & Kotschy ex Boiss.: an endemic and threatened Gymnosperm of the Thar Desert

Ephedra foliata Boiss. & Kotschy ex Boiss., (family – Ephedraceae), is an ecologically and economically important threatened Gymnosperm of the Indian Thar Desert. A method for micropropagation of E. foliata using nodal explant of mature female plant has been developed. Maximum bud-break (90 %) of the explant was obtained on MS medium supplemented with 1.5 mg l⁻¹ of benzyl adenine (BA) + additives. Explant produces 5.3 ± 0.40 shoots from single node with 3.25 ± 0.29 cm length. The multiplication of shoots in culture was affected by salt composition of media, types and concentrations of plant growth regulators (PGR’s) and their interactions, time of transfer of the cultures. Maximum number of shoots (26.3 ± 0.82 per culture vessel) were regenerated on MS medium modified by reducing the concentration of nitrates to half supplemented with 200 mg l⁻¹ ammonium sulphate {(NH₄) ₂SO₄} (MMS3) + BA (0.25 mg l⁻¹), Kinetin (Kin; 0.25 mg l⁻¹), Indole-3-acetic acid (IAA; 0.1 mg l⁻¹) and additives. The in vitro produced shoots rooted under ex vitro on soilrite moistened with one-fourth strength of MS macro salts in screw cap bottles by treating the shoot base (s) with 500 mg l⁻¹ of Indole-3-butyric acid (IBA) for 5 min. The micropropagated plants were hardened in the green house. The described protocol can be applicable for (i) large scale plant production (ii) establishment of plants in natural habitat and (iii) germplasm conservation of this endemic Gymnosperm of arid regions.     

Oleanane triterpenoids in the prevention and therapy of breast cancer: current evidence and future perspectives

Breast cancer is one of the most frequently diagnosed cancers and major cause of death in women in the world. Emerging evidence underscores the value of dietary and non-dietary phytochemicals, including triterpenoids, in the prevention and treatment of breast cancer. Oleanolic acid, an oleanane-type pentacyclic triterpenoid, is present in a large number of dietary and medicinal plants. Oleanolic acid and its derivatives exhibit several promising pharmacological activities, including antioxidant, anti-inflammatory, hepatoprotective, cardioprotective, antipruritic, spasmolytic, antiallergic, antimicrobial and antiviral effects. Numerous studies indicate that oleanolic acid and other oleanane triterpenoids modulate multiple intracellular signaling pathways and exert chemopreventive and antitumor activities in various in vitro and in vivo model systems. A series of novel synthetic oleanane triterpenoids have been prepared by chemical modifications of oleanolic acid and some of these compounds are considered to be the most potent anti-inflammatory and anticarcinogenic triterpenoids. Accumulating studies provide extensive evidence that synthetic oleanane derivatives inhibit proliferation and induce apoptosis of various cancer cells in vitro and demonstrate cancer preventive or antitumor efficacy in animal models of blood, breast, colon, connective tissue, liver, lung, pancreas, prostate and skin cancer. This review critically examines the potential role of oleanolic acid, oleanane triterpenoids and related synthetic compounds in the chemoprevention and treatment of mammary neoplasia. Both in vitro and in vivo studies on these agents and related molecular mechanisms are presented. Several challenges and future directions of research to translate already available impressive preclinical knowledge to clinical practice of breast cancer prevention and therapy are also presented.     

Dextromethorphan Mediated Bitter Taste Receptor Activation in the Pulmonary Circuit Causes Vasoconstriction

Activation of bitter taste receptors (T2Rs) in human airway smooth muscle cells leads to muscle relaxation and bronchodilation. This finding led to our hypothesis that T2Rs are expressed in human pulmonary artery smooth muscle cells and might be involved in regulating the vascular tone. RT-PCR was performed to reveal the expression of T2Rs in human pulmonary artery smooth muscle cells. Of the 25 T2Rs, 21 were expressed in these cells. Functional characterization was done by calcium imaging after stimulating the cells with different bitter agonists. Increased calcium responses were observed with most of the agonists, the largest increase seen for dextromethorphan. Previously in site-directed mutational studies, we have characterized the response of T2R1 to dextromethorphan, therefore, T2R1 was selected for further analysis in this study. Knockdown with T2R1 specific shRNA decreased mRNA levels, protein levels and dextromethorphan-induced calcium responses in pulmonary artery smooth muscle cells by up to 50%. To analyze if T2Rs are involved in regulating the pulmonary vascular tone, ex vivo studies using pulmonary arterial and airway rings were pursued. Myographic studies using porcine pulmonary arterial and airway rings showed that stimulation with dextromethorphan led to contraction of the pulmonary arterial and relaxation of the airway rings. This study shows that dextromethorphan, acting through T2R1, causes vasoconstrictor responses in the pulmonary circuit and relaxation in the airways.     

Characterization of Ofloxacin Interaction with Mutated (A91V) Quinolone Resistance Determining Region of DNA Gyrase in <Emphasis Type="Italic">Mycobacterium Leprae</Emphasis> through Computational Simulation

Mycobacterium leprae, the causal agent of leprosy is non-cultivable in vitro. Thus, the assessment of antibiotic activity against Mycobacterium leprae depends primarily upon the time-consuming mouse footpad system. The GyrA protein of Mycobacterium leprae is the target of the antimycobacterial drug, Ofloxacin. In recent times, the GyrA mutation (A91V) has been found to be resistant to Ofloxacin. This phenomenon has necessitated the development of new, long-acting antimycobacterial compounds. The underlying mechanism of drug resistance is not completely known. Currently, experimentally crystallized GyrA–DNA–OFLX models are not available for highlighting the binding and mechanism of Ofloxacin resistance. Hence, we employed computational approaches to characterize the Ofloxacin interaction with both the native and mutant forms of GyrA complexed with DNA. Binding energy measurements obtained from molecular docking studies highlights hydrogen bond-mediated efficient binding of Ofloxacin to Asp47 in the native GyrA-DNA complex in comparison with that of the mutant GyrA-DNA complex. Further, molecular dynamics studies highlighted the stable binding of Ofloxacin with native GyrA-DNA complex than with the mutant GyrA-DNA complex. This mechanism provided a plausible reason for the reported, reduced effect of Ofloxacin to control leprosy in individuals with the A91V mutation. Our report is the first of its kind wherein the basis for the Ofloxacin drug resistance mechanism has been explored with the help of ternary Mycobacterium leprae complex, GyrA–DNA–OFLX. These structural insights will provide useful information for designing new drugs to target the Ofloxacin-resistant DNA gyrase.     

Point mutation Arg153-His at surface of <Emphasis Type="Italic">Bacillus</Emphasis> lipase contributing towards increased thermostability and ester synthesis: insight into molecular network

In order to design proteins with improved properties i.e. thermostability, catalytic efficiency and to understand the mechanisms underlying, a thermostable variant of Bacillus lipase was generated by site-directed mutagenesis with enhanced thermal (?Tm = + 12 °C) and chemical (?Cm denaturation for Gdmcl = + 1.75 M) stability as compared to WT. Arg153-His variant showed 72-fold increase in thermostability (t ^1/2 = 6 h) at 60 °C as compared to WT (t ^1/2 = 5 min). Increase in thermostability might be contributed by the formation of additional hydrogen bonds between His153/AO-Arg106/ANH2 as well as His153-Arg106/ANE. The variant demonstrated broad substrate specificity. A maximum conversion of 59 and 62% was obtained for methyl oleate and methyl butyrate, respectively, using immobilized variant lipase, whereas immobilized WT enzyme synthesizes 35% methyl oleate. WT enzyme was unable to synthesize methyl butyrate as it showed negligible activity with pNP-butyrate.     

Benzoxazine derivatives of phytophenols show anti-plasmodial activity via sodium homeostasis disruption

Development of new class of anti-malarial drugs is an essential requirement for the elimination of malaria. Bioactive components present in medicinal plants and their chemically modified derivatives could be a way forward towards the discovery of effective anti-malarial drugs. Herein, we describe a new class of compounds, 1,3-benzoxazine derivatives of pharmacologically active phytophenols eugenol (compound 3) and isoeugenol (compound 4) synthesised on the principles of green chemistry, as anti-malarials. Compound 4, showed highest anti-malarial activity with no cytotoxicity towards mammalian cells. Compound 4 induced alterations in the intracellular Na⁺ levels and mitochondrial depolarisation in intraerythrocytic Plasmodium falciparum leading to cell death. Knowing P-type cation ATPase PfATP4 is a regulator for sodium homeostasis, binding of compound 3, compound 4 and eugenol to PfATP4 was analysed by molecular docking studies. Compounds showed binding to the catalytic pocket of PfATP4, however compound 4 showed stronger binding due to the presence of propylene functionality, which corroborates its higher anti-malarial activity. Furthermore, anti-malarial half maximal effective concentration of compound 4 was reduced to 490?nM from 17.54?µM with nanomaterial graphene oxide. Altogether, this study presents anti-plasmodial potential of benzoxazine derivatives of phytophenols and establishes disruption of parasite sodium homeostasis as their mechanism of action.     

Biochemical and molecular studies on the resistance mechanisms in tea [<Emphasis Type="Italic">Camellia sinensis</Emphasis> (L.) O. Kuntze] against blister blight disease

Tea (Camellia sinensis) plantations are exposed to biotic and abiotic stresses. Among the biotic factors, blister blight (BB), caused by Exobasidium vexans, affects the quality and quantity of the product and demands high fungicide application. A long term solution for disease resistance would require the knowledge of the basic molecular and biochemical changes occurring in plant as an attempt to resist the pathogen and limit the spread of the disease which can further help in developing resistant cultivars using biotechnological tools. Thus, gene expression studies using the cDNA based suppressive subtractive hybridization library, characterization of genes for pathogenesis related (PR) proteins [chitinase (CsCHIT), glucanase (CsGLUC), phenylalanine ammonia lyase (CsPAL)] and genes in flavonoid pathway were accessed in the BB resistant and susceptible cultivars, SA6 and TES34, respectively. Further, biochemical analysis of PR and antioxidant enzymes (POX, APX, SOD) involved in BB resistance have been carried out to investigate the potential molecular and biochemical changes. Various stages of pathogen development had varied impact on PR protein, flavonoid pathway and anti-oxidative enzymes and indicates the possible role of reactive oxygen species, lignins, flavonoids, anthocyanins and other synthesized compounds in acting as antimicrobial/antifungal agents in tea cultivars.     

Novel nicotinamide analog as inhibitor of nicotinamide N-methyltransferase

Nicotinamide N-methyltransferase (NNMT) has been linked to obesity and diabetes. We have identified a novel nicotinamide (NA) analog, compound 12 that inhibited NNMT enzymatic activity and reduced the formation of 1-methyl-nicotinamide (MNA), the primary metabolite of NA by ～80% at 2?h when dosed in mice orally at 50?mg/kg.