Cadinane sesquiterpenoids of Phomopsis cassiae, an endophytic fungus associated with Cassia spectabilis (Leguminosae)

Five cadinane sesquiterpenes derivatives were isolated by bioassay-guided fractionation from Phomopis cassiae, an endophytic fungus isolated from Cassia spectabilis. The structures of the two diastereoisomeric 3,9,12-trihydroxycalamenenes (1, 2); 3,12-dihydroxycalamenene (3); 3,12-dihydroxycadalene (4) and 3,11,12-trihydroxycadalene (5) were established on the basis of analyses of 1D and 2D NMR and HRTOFMS experiments. Antifungal activity of the isolates was evaluated against Cladosporium sphaerospermum and Cladosporium cladosporioides, revealing 5 as the most active compound.     

Competition between Nitrospira spp. and Nitrobacter spp. in nitrite-oxidizing bioreactors

In this work the question was addressed if in nitrite-oxidizing activated sludge systems the environmental competition between Nitrobacter spp. and Nitrospira spp., which only recently has been discovered to play a role in these systems, is affected by the nitrite concentrations. Two parallel chemostats were inoculated with nitrifying-activated sludge containing Nitrospira and operated under identical conditions. After addition of Nitrobacter to both chemostats, the nitrite concentration in the influent of one of the chemostats was increased such that nitrite peaks in the bulk liquid of this reactor were detected. The other chemostat served as control reactor, which always had a constant nitrite influent concentration. The relative cellular area (RCA) of Nitrospira and Nitrobacter was determined by quantitative fluorescence in situ hybridization (FISH). The nitrite perturbation stimulated the growth of Nitrobacter while in the undisturbed control chemostat Nitrospira dominated. Overall, the results of this experimental study support the hypothesis that Nitrobacter is a superior competitor when resources are abundant, while Nitrospira thrive under conditions of resource scarcity. Interestingly, the dominance of Nitrobacter over Nitrospira, caused by the elevated nitrite concentrations, could not be reverted by lowering the available nitrite concentration to the original level. One possible explanation for this result is that when Nitrobacter is present at a certain cell density it is able to inhibit the growth of Nitrospira. An alternative explanation would be that the length of the experimental period was not long enough to observe an increase of the Nitrospira population.     

Knowledge and attitudes of dentists regarding ageing and the elderly

doi: 10.1111/j.1741‐2358.2011.00534.x
Knowledge and attitudes of dentists regarding ageing and the elderly Objective: This study was aimed to identify the knowledge and attitudes of dentists regarding ageing and the elderly. Background: As the population ages, there is a greater demand for differentiated care from health professionals. However, the treatment needs of the elderly population are not sufficiently addressed, particularly in developing countries. Materials and methods: An official list of all dentists registered in the city of Belo Horizonte, Brazil, was obtained from the Regional Dentistry Council. A questionnaire was delivered to 276 randomly selected dentists; the survey contained questions designed to characterise the sample and identify dentists’ conduct towards elderly patients. A Likert scale was used to identify knowledge regarding care for the elderly and attitudes towards ageing. Results: Women demonstrated more positive attitudes towards the elderly. Graduates who worked in the public sector demonstrated a greater knowledge of geriatric dentistry (p < 0.05). Attending specific continuing education courses had no influence over the dentists’ willingness to treat the elderly population. Significant associations were not found between attitudes and knowledge regarding the elderly. Conclusion: Dentists who worked in the public sector demonstrated a greater knowledge regarding the elderly. This knowledge did not influence attitudes towards ageing. Women demonstrated a more positive attitude regarding ageing and dental care.     

Involvement of GABAergic and glutamatergic systems in the anticonvulsant activity of 3-alkynyl selenophene in 21?day-old rats

In this study, we investigated the role of GABAergic and glutamatergic systems in the anticonvulsant action of 3-alkynyl selenophene (3-ASP) in a pilocarpine (PC) model of seizures. To this purpose, 21 day-old rats were administered with an anticonvulsant dose of 3-ASP (50 mg/kg, per oral, p.o.), and [(3)H]γ-aminobutyric acid (GABA) and [(3)H]glutamate uptakes were carried out in slices of cerebral cortex and hippocampus. [(3)H]GABA uptake was decreased in cerebral cortex (64%) and hippocampus (58%) slices of 21 day-old rats treated with 3-ASP. In contrast, no alteration was observed in [(3)H]glutamate uptake in cerebral cortex and hippocampus slices of 21 day-old rats that received 3-ASP. Considering the drugs that increase synaptic GABA levels, by inhibiting its uptake or catabolism, are effective anticonvulsants, we further investigated the possible interaction between sub-effective doses of 3-ASP and GABA uptake or GABA transaminase (GABA-T) inhibitors in PC-induced seizures in 21 day-old rats. For this end, sub-effective doses of 3-ASP (10 mg/kg, p.o.) and DL-2,4-diamino-n-butyric acid hydrochloride (DABA, an inhibitor of GABA uptake--2 mg/kg, intraperitoneally; i.p.) or aminooxyacetic acid hemihydrochloride (AOAA; a GABA-T inhibitor--10 mg/kg, i.p.) were co-administrated to 21 day-old rats before PC (400 mg/kg; i.p.) treatment, and the appearance of seizures was recorded. Results demonstrated that treatment with AOAA and 3-ASP or DABA and 3-ASP significantly abolished the number of convulsing animals induced by PC. The present study indicates that 3-ASP reduced [(3)H]GABA uptake, suggesting that its anticonvulsant action is related to an increase in inhibitory tonus.     

Akt-dependent Skp2 mRNA translation is required for exiting contact inhibition, oncogenesis, and adipogenesis

The requirement of Akt for cell proliferation and oncogenesis is mammalian target of rapamycin complex 1 (mTORC1) dependent. SV40 large T expression in Akt-deficient cells restores cell proliferation rate, but is insufficient for exiting contact inhibition and oncogene-induced anchorage-independent growth, because of a failure to promote Skp2 mRNA translation. Skp2 mRNA and protein are induced upon exiting contact inhibition, which enables entry into mitosis. While Skp2 mRNA is induced in Akt-deficient cells, it is not translated, preventing entry into mitosis. Restoring Skp2 expression in Akt-deficient cells is sufficient to restore exit from contact inhibition and oncogenesis. Skp2 mRNA translation is dependent on mTORC1 and the eukaryotic translation initiation factor 4E (eIF4E). Thus, the requirement of Akt for exiting contact inhibition is mediated by the induction of Skp2 mRNA translation in eIF4E-dependent mechanism. These results provide a new insight into the role of the Akt/mTORC1/eIF4E axis in tumourigenesis. Akt-dependent Skp2 mRNA translation is also required for mitotic clonal expansion (MCE)--the earliest event in adipogenesis. Skp2 re-expression in Akt-deficient preadipocytes, which are impaired in adipogenesis, is sufficient to restore adipogenesis. These results uncover the mechanism by which Akt mediates adipogenesis.     

Dissecting structure-function-stability relationships of a thermostable GH5-CBM3 cellulase from Bacillus subtilis 168

Cellulases participate in a number of biological events, such as plant cell wall remodelling, nematode parasitism and microbial carbon uptake. Their ability to depolymerize crystalline cellulose is of great biotechnological interest for environmentally compatible production of fuels from lignocellulosic biomass. However, industrial use of cellulases is somewhat limited by both their low catalytic efficiency and stability. In the present study, we conducted a detailed functional and structural characterization of the thermostable BsCel5A (Bacillus subtilis cellulase 5A), which consists of a GH5 (glycoside hydrolase 5) catalytic domain fused to a CBM3 (family 3 carbohydrate-binding module). NMR structural analysis revealed that the Bacillus CBM3 represents a new subfamily, which lacks the classical calcium-binding motif, and variations in NMR frequencies in the presence of cellopentaose showed the importance of polar residues in the carbohydrate interaction. Together with the catalytic domain, the CBM3 forms a large planar surface for cellulose recognition, which conducts the substrate in a proper conformation to the active site and increases enzymatic efficiency. Notably, the manganese ion was demonstrated to have a hyper-stabilizing effect on BsCel5A, and by using deletion constructs and X-ray crystallography we determined that this effect maps to a negatively charged motif located at the opposite face of the catalytic site.     

Microsatellite Markers for Characterization of Native and Introduced Populations of Plasmopara viticola, the Causal Agent of Grapevine Downy Mildew

We reported 31 microsatellite markers that have been developed from microsatellite-enriched and direct shotgun pyrosequencing libraries of Plasmopara viticola, the causal agent of grapevine downy mildew. These markers were optimized for population genetics applications and used to characterize 96 P. viticola isolates from three European and three North American populations.     

Evaluation of Moringa oleifera seed flour as a flocculating agent for potential biodiesel producer microalgae

Microalgal biofuel alternatives have been hindered by their cost and energy intensive production. In the microalgal harvesting process, the intermediate step of flocculation shows potential in drastically reducing the need for costly centrifugation processes. Moringa oleifera seeds, which have been used for water treatment due to their high flocculation potential, low cost and low toxicity, are presented in this paper as strong candidate for flocculating Chlorella vulgaris, a microalgae with high biodiesel production potential. Early results of our group showed a very high flocculation (around 85% of biomass recovery). The aim of this work was to investigate the influence of Moringa oleifera seed flour concentration, sedimentation time and pH on the flocculation efficiency. Cell suspensions treated with Moringa seed flour (1 g L^-1) had their flocculation significantly increased with the rise of pH, reaching 89% of flocculation in 120 min at pH 9.2. Sedimentation time of 120 min and a concentration of 0.6 g L^-1 proved to be ample for substantial flocculation efficiency. In spite of the need for more research to ensure the economic viability and sustainability of this process, these results corroborate Moringa oleifera seeds as a strong candidate as a bioflocculant for Chlorella vulgaris cells and indicate optimal pH range of its action.     

Do the phenology and functional stem attributes of woody species allow for the identification of functional groups in the semiarid region of Brazil?

The phenology of tree species in environments that are subject to strong climatic seasonality is mainly determined by water availability, which may vary as a function of wood density. The relationship among phenology, water potential, wood density and the capacity of water storage in the stem were determined for woody species of caatinga vegetation (dry forest) in the semiarid region of NE Brazil. Leaf flush and fall, flowering and fruiting events were recorded over a 31-month period, and the water potential was measured over a two-year period. These data were related to precipitation, water availability in the soil and photoperiod. Seven deciduous species exhibited low wood density (DLWD,?<0.5?g?cm^?3), high capacity of water storage in the stem (until 250?% of the dry weight) and high water potential during the year, as opposed to 15 deciduous species that showed high wood density (DHWD,?≥0.5?g?cm^?3). Leaf flush, flowering and the fruiting of DHWD species were related to precipitation, whereas these phenological events occurred at the end of the dry season and/or the beginning of the rainy season for DLWD species and were related to the photoperiod. The two evergreen species showed variations of water potential that were intermediate between those of DHWD and DLWD deciduous species, leaf flush during the dry season and flowering at the end of dry season. These results suggest the existence of three functional groups: evergreen species, DHWD deciduous species and DLWD deciduous species.