Structure of acacigenin-B,a novel triterpene ester isolated from Acacia concinna

The structure of acacigenin-B, a novel ester genin from the pods of Acacia concinna was established from its PMR and ¹³ C NMR spectra. It was identified as the 21-hydroxy ester of acacic acid; the esterifying acid was a hitherto unknown monoterpene acid of tetrahydrofuranoid structure. This appears to be the first report of a higher terpenoid forming an ester with a monoterpene acid     

An Intracellular Iron Chelator Pleiotropically Suppresses Enzymatic and Growth Defects of Superoxide Dismutase-Deficient Escherichia coli

Mutants of Escherichia coli that lack cytoplasmic superoxide dismutase (SOD) exhibit auxotrophies for sulfur-containing, branched-chain, and aromatic amino acids and cannot catabolize nonfermentable carbon sources. A secondary-site mutation substantially relieved all of these growth defects. The requirement for fermentable carbon and the branched-chain auxotrophy occur because superoxide (O2-) leaches iron from the [4Fe-4S] clusters of a family of dehydratases, thereby inactivating them; the suppression of these phenotypes was mediated by the restoration of activity to these dehydratases, evidently without changing the intracellular concentration of O2-. Cloning, complementation, and sequence analysis identified the suppressor mutation to be in dapD, which encodes tetrahydrodipicolinate succinylase, an enzyme involved in diaminopimelate and lysine biosynthesis. A block in dapB, which encodes dihydrodipicolinate reductase in the same pathway, conferred similar protection. Genetic analysis indicated that the protection stems from the intracellular accumulation of tetrahydro- or dihydrodipicolinate. Heterologous expression in the SOD mutants of the dipicolinate synthase of Bacillus subtilis generated dipicolinate and similarly protected them. Dipicolinates are excellent iron chelators, and their accumulation in the cell triggered derepression of the Fur regulon and a large increase in the intracellular pool of free iron, presumably as a dipicolinate chelate. A fur mutation only partially relieved the auxotrophies, indicating that Fur derepression assists but is not sufficient for suppression. It seems plausible that the abundant internal iron permits efficient reactivation of superoxide-damaged iron-sulfur clusters. This result provides circumstantial evidence that the sulfur and aromatic auxotrophies of SOD mutants are also directly or indirectly linked to iron metabolism.     

Growth inhibition of fouling diatoms by antipatharian colonies

Growth inhibition of four dominant marine fouling diatoms by alcohol extracts of antipatharian colonies, collected off the east coast of India, are reported here. Of the three antipatharian colonies tested one antipatharian inhibited the growth of all the four fouling diatoms on glass surface, implying the presence of potent algal growth inhibitors whilst the other extracts were species specific in their action. The same cells exhibited normal growth, when transferred in extract free media, indicating a nontoxic mode of action. The effective concentration for 50% inhibition (EC50) ranged from 90 microg/ml (Nitzschia sp.) to 756 microg/ml (Amphora sp). The EC50 values for N. subinflata and N. crucicula were 215 microg/ml and 108 microg/ml, respectively. The active extracts totally arrested the silicate uptake by diatoms treated with EC100 values, in relation to controls. The degree of silicate uptake impairment varies with the test organisms. The results show the presence of antifouling agents in this group of organisms. This is the first report of anltifouling properties of antipatharian colonies.     

Three eudesmanolides from Pluchea rosea

Three eudesmanolides of Pluchea rosea were found to be structurally related to the eudesmane, cuauthemone, earlier reported from plants of the same genus.     

Fecal occult blood testing instructions and impact on patient adherence

IntroductionAlthough the physician's role with patients is crucial in encouraging FOBT screening, the nature and content of physician-patient discussions about FOBT screening is unclear. As part of a larger study, this paper reports on our analyses of physician beliefs about fecal occult blood testing (FOBT) and strategies they employed to enhance patient adherence. The second aim of this paper is to report on the perceptions of individuals at average risk for colorectal cancer (CRC) in regard to their awareness of the FOBT and their responses to physician recommendations about FOBT screening.MethodsThe larger study was conducted in urban and rural Manitoba, Canada between 2008 and 2010. We used a qualitative design and conducted semi-structured, audio-recorded interviews with 15 physicians and 27 individuals at average risk for CRC. We included data from 11 family members or friends on their perspectives of FOBT instructions as individuals who were also at average risk for CRC and had their own experiences with CRC screening recommendations.ResultsDespite widespread knowledge of The Canadian Task Force on Preventive Health Care CRC screening guidelines, physician attitudes, behaviors, and instructions were not uniform in promoting patient adherence to FOBT screening. Individuals at average-risk for CRC identified that FOBT instructions were confusing and burdensome, which in turn served as a barrier in their adherence to FOBT screening.ConclusionsVariation in FOBT instruction counseling in relation to the recommended age of individuals at average risk for CRC, as well as adequate patient preparation affected patient adherence. We recommend uniform or standardized instructions and counseling by health care providers who administer the FOBT kit to patients to promote adherence to recommended CRC screening.     

Production of Industrial Enzymes (Amylase,Carboxymethylcellulase and Protease) by Bacteria Isolated from Marine Sedentary Organisms

The abilities of bacteria isolated from eight marine sedentary organisms, six marine sponges (Spirastrella sp., Phyllospongia sp., Ircinia sp., Aaptos sp., Azorica sp. and Axinella sp.), one soft coral (Lobophytum sp.) and one alga (Sargassum sp.) to produce industrial enzymes (amylase, carboxymethylcellulase and protease) were examined. The mean total viable counts of the bacterial isolates ranged from 8.7 × 10⁴ to 8.4 × 10⁵ cfu/g wet weight of the organism. All eight organisms harboured amylase (0.05–0.5 IU/ml), carboxymethylcellulase (0.05–0.5 IU/ml) and protease (0.1–0.5 IU/ml) producing bacteria. Of 56 bacterial strains tested, as many as 60 to 83% of the strains produced at least one of the three enzymes, and 47% of strains were able to produce all three enzymes. High activities (> 0.5 IU/ml) of the three enzymes were recorded in bacterial strains belonging to the genera Alcaligenes and Bacillus. From the results of this study, it appears that bacteria associated with marine sedentary organisms are the novel source of industrial enzymes for possible commercial applications and may play an important role in enzyme‐catalysed organic matter cycling in marine environments.     

Antifungal efficacy of bacteria isolated from marine sedentary organisms

The antibiotic-producing ability of 57 bacteria isolated from 8 marine sedentary organisms, 6 sponges (Spirastrella sp.,Phyllospongia sp.,Ircinia sp.,Aaptos sp.,Azorica sp.,Axinella sp.), 1 soft coral (Lobophytum sp.) and 1 alga (Sargassum sp.), was evaluated against 6 phytopathogenic fungi (Helminthosporium oryzae, Rhizoctonium solani, Pyricularia oryzae, Fusarium oxysporum, Aspergillus oryzae andA. fumigatus). Bacteria of the genusBacillus (20%),Pseudomonas (33%) andFlavobacterium (40%) were predominant among the heterotrophic bacteria isolated from the marine sponges, soft coral and alga, respectively. Bioassay results revealed that 36 (63%) bacterial isolates displayed antifungal activity against at least one fungus, the alga (Sargassum sp.) being the source of highest number (80%) of producer strains. Twelve bacterial isolates inhibited all fungi. The MIC of the organic extracts of 12 bacteria ranged from 0.3 to 22.8 mg/L.     

What is the role of family in promoting faecal occult blood test screening? Exploring physician,average-risk individual,and family perceptions

Background: Although the number of Canadians being screened for colon cancer is rising, only 40% of Canadians aged 50 years or older reported they had engaged in faecal occult blood test (FOBT) screening as recommended. The notion of ‘partnerships’ that is inclusive of physicians, individuals at average-risk for colorectal cancer, and influential family members is receiving more attention in primary health care literature and policy on promoting health maintenance behaviours. To the best of our knowledge there are no studies that have taken a tripartite approach in describing perspectives of these three key stakeholders on the role of family in promoting adherence to FOBT. The aim of this study was to address the gap in understanding the perspectives of primary care physicians, individuals at average-risk for colorectal cancer, and family on family role in promoting adherence to FOBT screening. Method: We employed a qualitative design and conducted semi-structured interviews with 15 physicians, 27 patients at average-risk for colorectal cancer, and 19 family members or friends from urban and rural Manitoba, Canada between October 2008 and March 2010. Interviews were audio-recorded, transcribed verbatim, and analysed using content analysis and constant comparative techniques. Results: While physicians described a clear role for family in managing chronic disease or dealing with acute or serious illness, they identified barriers in working with family to promote FOBT screening: lack of time, privacy and confidentiality concerns, and family dynamics. Conversely, patients and family described instrumental, emotional, informational, and appraisal roles that family play in promoting FOBT outside medical encounters. Conclusion: Adherence to colorectal cancer screening is based on supportive ‘patient–physician’ dialogue that is separate from assistive ‘patient–family member’ relations. Further research is required to explore social support mechanisms involving family members outside medical encounters that hold promise in boosting self-efficacy, overcoming barriers, and gaining positive reinforcement for individuals at average-risk when making the decision to engage in FOBT.     

Antifouling activities of octocorals on some marine microfoulers

The antifouling activities of vacuum-dried 70% aqueous alcohol extracts of four gorgonian and five soft corals against four dominant marine fouling diatoms (Navicula subinflata Grun, N. crucicula Smith, Amphora sp., Nitzschia sp.) are described. Of the 36 possible combinations (9 corals x 4 diatoms) 23 of the interactions (64%) showed 100% activity. Extracts of the gorgonian coral Echinogorgia complexa Nutting and the soft coral Dendronephthya (Morchellana) sp. showed 100% growth inhibition against all four fouling diatoms, implying the presence of potent broad spectrum antifouling compounds; other extracts showed more limited species specificity. Exposed cells when transferred to extract-free media, resumed normal growth indicating a nontoxic way of action. The effective concentration for 50% growth inhibition of the attached cells (EC50) varied for each extract and test organism used. The EC50 values for the extract of the gorgonian coral E. complexa against the fouling diatoms ranged from 86 microg/ml (N. subinflata) to 505 microg/ml (Amphora sp.) whereas the EC50 values for extracts of the soft coral Dendronephthya (Morchellana) sp. varied from 28 microg/ml (N. crucicula) to 415 microg/ml (Amphora sp.). The results support the hypothesis that octocorals contain antifouling agents, which could be exploited for the development of nontoxic natural antifouling technology.     

Characterization of acetylcholinesterase from Arthrobacter ilicis associated with the marine sponge (Spirastrella sp.)

The bacterium Arthrobacter ilicis isolated from the marine sponge Spirastrella sp. produces extracellular serine type acetylcholinesterase. The maximum enzyme activity was found at 45 °C and pH 8·0. The activation and deactivation energies, calculated from an Arrhenius plot, were 13·68 and 36·96 kcal mol⁻¹, respectively. The enzyme was not affected by the addition of the major cations of sea water, such as Ca²⁺ and Mg²⁺ at 25 mmol l⁻¹, and was strongly inhibited by EDTA and different organophosphorus and carbamate compounds at 5 mmol l^−1.