Prevalence and pathology of the nematode Heterakis gallinarum, the trematode Paratanaisia bragai, and the protozoan Histomonas meleagridis in the turkey, Meleagris gallopavo

The prevalence of infection and associated pathology induced by two helminth and one protozoan species infecting Brazilian turkeys are reported. The intestinal nematode Heterakis gallinarum appeared with a prevalence of 70% in the infected birds, without gross lesions when not associated to the protozoan Histomonas meleagridis. Histological findings in the ceca were represented by the presence of H. gallinarum worms, intense chronic diffuse inflammatory processes with mononuclear and polymorphonuclear (heterophils) leucocyte infiltrations. The prevalence of the protozoan H. meleagridis associated to H. gallinarum was of 2.5% and microscopic examination revealed a severe inflammatory process in the liver and cecum with the presence of small clear areas with round eosinophilic parasites. Gross lesions were absent in turkeys infected with the renal digenetic trematode Paratanaisia bragai; the parasite was prevalent in 20% of the cases and cross-sections of the kidneys showed a remarkable distension of the collecting ducts with several worms in the lumen. The walls of the ducts presented a discrete heterophilic infiltrate among mononuclear cells.     

A Mutation in the luxS gene influences Listeria monocytogenes biofilm formation

Using a Vibrio harveyi reporter strain, we demonstrated that Listeria monocytogenes secretes a functional autoinducer 2 (AI-2)-like signal. A luxS-deficient mutant produced a denser biofilm and attached to a glass surface 19-fold better than the parent strain. Exogenous AI-2 failed to restore the wild-type phenotype to the mutant. It seems that an intact luxS gene is associated with repression of components required for attachment and biofilm formation.     

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.