Water recycling by Amazonian vegetation: coupled versus uncoupled vegetation-climate interactions

To demonstrate the relationship between Amazonian vegetation and surface water dynamics, specifically, the recycling of water via evapotranspiration (ET), we compare two general circulation model experiments; one that couples the IS92a scenario of future CO2 emissions to a land-surface scheme with dynamic vegetation (coupled) and the other to fixed vegetation (uncoupled). Because the only difference between simulations involves vegetation coupling, any alterations to surface energy and water balance must be due to vegetation feedbacks. The proportion of water recycled back to the atmosphere is relatively conserved through time for both experiments. Absolute value of recycled water is lower in our coupled relative to our uncoupled simulation as a result of increasing atmospheric CO2 that in turn promotes lowering of stomatal conductance and increase in water-use efficiency. Bowen ratio increases with decreasing per cent broadleaf cover, with the greatest rate of change occurring at high vegetation cover (above 70% broadleaf cover). Over the duration of the climate change simulation, precipitation is reduced by an extra 30% in the coupled relative to the uncoupled simulations. Lifting condensation level (proxy for base height of cumulus cloud formation) is 520m higher in our coupled relative to uncoupled simulations.     

Evaluation of Antimicrobial Activity of Cashew Tree Gum

Crude and purified cashew tree gum were tested for their antimicrobial activity against bacteria, yeast and fungi. Their use was also evaluated as a carbon source for microbial growth. Cashew gum presented only a weak activity against Saccharomyces cerevisiae and no activity was observed against all other microorganisms tested. The possibility that removal of anacardic acid present in the raw gum during purification may explain the negative results obtained was discussed. When purified cashew tree gum was used as carbon source, only Listeria monocytogenes, Saccharomyces cerevisiae and Kluyveromyces marxianus did not grow after 5 days of incubation.     

Alkaline protease from <Emphasis Type="Italic">Bacillus sp.</Emphasis> isolated from coffee bean grown on cheese whey

Two strains of Bacillus, one from a culture collection (B. subtilis ATCC 6633) and a wild type (Bacillus sp. UFLA 817CF) isolated during coffee fermentation in the south of Minas Gerais, Brazil, were evaluated in relation to secretion of alkaline proteases. The strains were grown on nutrient broth, nutrient broth with sodium caseinate and nutrient broth with three different concentrations of cheese whey powder for 72 h. Samples were collected at 24-h intervals to evaluate the proteolytic activity, protein content and cell population. Maximum protease activity was observed after 24-h growth for both the microorganisms, a period that coincided with the end of the exponential phase. The specific activity values were, respectively, 839.8 U/mg for B. subtilis ATCC 6633 and 975.9 U/mg for Bacillus sp. UFLA 817CF. The 60% saturation presented the best results for specific protease activity in all the growth culture media tested with B. sp. UFLA 817CF. Bacillus sp. UFLA 817CF showed highest enzymatic activity at pH 9.0 and 40°C in the three culture media tested. The protease obtained from culture of the wild Bacillus strain presented stability at pH 7.0 and considerable heat stability at 40°C and 50°C, and could be an alternative for the industry to utilize cheese whey to produce proteolytic enzymes.     

Daily variation of melatonin content in the optic lobes of the crab Neohelice granulata.

Melatonin is a biogenic amine, known from almost all phyla of living organisms. In vertebrates melatonin is produced rhythmically in the pinealocytes of the pineal gland, relaying information of the environmental light/dark cycle to the organism. With regard to crustaceans only a handful of studies exist that has attempted to identify the presence and possible daily variation of this substance. We set out to investigate whether in the crab Neohelice granulata melatonin was produced in the optic lobes of these animals and underwent rhythmic fluctuations related to the daily light/dark cycle. Our experimental animals were divided into three groups exposed to different photoperiods: normal photoperiod (12L:12D), constant dark (DD), and constant light (LL). The optic lobes were collected every 4 hours over a 24-h period for melatonin quantification by radioimmunoassay (RIA). N. granulata kept under 12 L:12D and DD conditions, showed daily melatonin variations with two peaks of abundance (p<0.05), one during the day and another, more extensive one, at night. Under LL-conditions no significant daily variations were noticeable (p>0.05). These results demonstrate the presence of a daily biphasic fall and rise of melatonin in the eyestalk of N. granulata and suggest that continuous exposure to light inhibits the production of melatonin synthesis.     

Response surface method to optimize the production and characterization of lipase from Penicillium verrucosum in solid-state fermentation

Current studies about lipase production by solid-state fermentation involve the use of agro-industrial residues towards developing cost-effective systems directed to large-scale commercialization of enzyme-catalyzed processes. In this work, lipase production and partial characterization of the crude enzymatic extracts obtained by Penicillium verrucosum using soybean bran as substrate was investigated. Different inductors were evaluated and the results showed that there is no influence of this variable on the lipase production, while temperature and initial moisture were the main factors that affected enzyme production. The optimized cultivation temperature (27.5 °C) and initial moisture of substrate (55%) were determined using the response surface methodology. Kinetics of lipase production was followed at the optimized growth conditions. Optimum lipase yield was 40 U/g of dry bran. The crude enzymatic extract showed optimal activity in the range from 30 to 45 °C and in pH 7.0.     

Purification and partial characterization of a bacteriocin produced by Eikenella corrodens

Aims: The purpose of this study was to purify and characterize a bacteriocin produced by Eikenella corrodens A32E2. Methods and Results: Peptostreptococcus anaerobius ATCC27337 was used as indicator strain in antagonistic assays for bacteriocin‐producing E. corrodens A32E2. Protein extraction was influenced by pH and buffer composition. The protein was active in the pH range 6–8. Inhibitory activity was lost by both heating and treatment with proteolytic enzymes and decreased with organic solvents. The substance is rather unstable but maintains 100% of its activity after being exposed to acetone and when stored at ?70°C. The antagonistic substance was first precipitated by ammonium sulfate and further partially purified by Mono‐Q FPLC and C‐18 HPLC. Mass spectrometry analysis showed that the molecular mass was 23 625 Da, and the sequence obtained for the N‐terminus was: Met‐Asn‐Phe‐Asp‐Glu‐Lys‐Val‐Gly‐Lys‐Val‐X‐Phe‐Lys‐Val‐Gly‐Asp. Conclusions: The evidence presented in this study supports the idea that an antagonistic substance produced by E. corrodens A32E2 isolated from a periodontal diseased site is a novel bacteriocin, which we designate corrodecin. Significance and Impact of the Study:  We anticipated that corrodecin might play an important role at the periodontal site. This compound could also be attractive in biotechnological applications as an interesting tool for oral ecosystem control.     

Biodiversity surrogate groups and conservation priority areas: birds of the Brazilian Cerrado

The choice of surrogates of biodiversity is an important aspect in conservation biology. The quantification of the coincidence in the spatial patterns of species richness and rarity between different groups and the vulnerability of groups are different approaches frequently considered to accomplish this task. However, a more appropriate approach is to verify the efficiency of priority networks selected using information from one group of organisms to capture the biodiversity of other groups. Using a deconstructive approach, the main purposes of this study were to evaluate the performance of some orders and families of birds in the Cerrado biome (a savanna-like biome) as surrogates of other bird groups, in a pairwise analysis, and to investigate the characteristics of these groups that predict the efficiency in representation of other groups. We used biogeographical data on bird orders or families with more than 10 species that occur in the Brazilian Cerrado. The best surrogate group was the Thamnophilidae. Moreover, this group is not the most specious, favouring further survey efforts that are necessary to verify the conservation value of areas at suitable scales. The majority of the species from this family are dependent on forest habitats, one of the characteristics that most influenced representativeness level, probably due to the spatial distribution of these habitats throughout the Brazilian Cerrado. Beta diversity patterns of the different groups also affected representativeness, and our analyses showed that the networks selected by a surrogate group will be more effective in the representation of other groups of species if their patterns of beta diversity (not richness) are correlated.     

Daily variation of melatonin content in the optic lobes of the crab Neohelice granulata

Melatonin is a biogenic amine, known from almost all phyla of living organisms. In vertebrates melatonin is produced rhythmically in the pinealocytes of the pineal gland, relaying information of the environmental light/dark cycle to the organism. With regard to crustaceans only a handful of studies exist that has attempted to identify the presence and possible daily variation of this substance. We set out to investigate whether in the crab Neohelice granulata melatonin was produced in the optic lobes of these animals and underwent rhythmic fluctuations related to the daily light/dark cycle. Our experimental animals were divided into three groups exposed to different photoperiods: normal photoperiod (12L:12D), constant dark (DD), and constant light (LL). The optic lobes were collected every 4 hours over a 24-h period for melatonin quantification by radioimmunoassay (RIA). N. granulata kept under 12 L:12D and DD conditions, showed daily melatonin variations with two peaks of abundance (p<0.05), one during the day and another, more extensive one, at night. Under LL-conditions no significant daily variations were noticeable (p>0.05). These results demonstrate the presence of a daily biphasic fall and rise of melatonin in the eyestalk of N. granulata and suggest that continuous exposure to light inhibits the production of melatonin synthesis.     

Do consecutive flower visits within a crown diminish fruit set in mass‐flowering Hancornia speciosa (Apocynaceae)?

Hancornia speciosa is a self-incompatible, mass-flowering, sphingophilous fruit crop (mangaba) of northeast and central Brazil. The flowers have a precise pollination apparatus, which optimizes pollen transfer between flower and pollinator. While the pollination mechanism avoids self-pollination, mass-flowering promotes geitonogamy. During a flower visit, almost half of the exogenous pollen grains adhering to the proboscis are deposited on the stigma surface. A pollination experiment with a nylon thread simulating six consecutive flower visits within a crown revealed that only the first two flowers visited (positions 1 and 2) are highly likely to set fruit. Super-production of flowers, and consequently obligate low fruit set, seem to be part of the reproductive strategy of the obligate outcrossing plant, Hancornia speciosa.