Effects of Palm Oil Deodorizer Distillate on the Ruminal Environment of Sheep.

This study aimed to assess the impact of palm oil deodorizer distillate (POD) on the ruminal environment, including (i) microbial community, (ii) ruminal degradability, and (iii) apparent digestibility in sheep. The data used were derived from twenty rumen-cannulated sheep fed five isoproteic and isofiber diets based on elephant grass (Pennisetum purpureum Schum. cv. Roxo) silage supplemented with 0, 25, 50, 75, or 100 g kg-1 POD on a dry matter (DM) basis. Rumen fluid samples were collected three hours after feeding directly from the ventral sac of the rumen via a cannula and then subjected to DNA extraction, which was subsequently used for 16S rDNA amplification, followed by sequencing and diversity analysis. In this study, the microbial diversity was dominated by Bacteroidetes and Firmicutes, followed by Euryarchaetoa, Actinobacteria, and Tenericutes, in the ruminal environment, and was slightly modified when supplemented with the POD up to 100 g/kg (10%), leading to only a slight decrease in the diversity index. The ruminal degradability, ruminal fermentation parameters, and apparent digestibility were slightly compromised by the inclusion of up to 25 g of POD per kg of DM, and larger inclusions interfered with the ruminal degradability of fibrous fractions and the apparent digestibility of dry matter. This lipid supplement showed good results for feeding sheep and is an inexpensive and abundant alternative in the regional market.

Amazonian deforestation and soil biodiversity.

Clearance and perturbation of Amazonian forests are one of the greatest threats to tropical biodiversity conservation of our times. A better understanding of how soil communities respond to Amazonian deforestation is crucially needed to inform policy interventions that effectively protect biodiversity and the essential ecosystem services it provides. We assessed the impact of deforestation and ecosystem conversion to arable land on Amazonian soil biodiversity through a meta-analysis. We analyzed 274 pairwise comparisons of soil biodiversity in Amazonian primary forests and sites under different stages of deforestation and land-use conversion: disturbed (wildfire and selective logging) and slash-and-burnt forests, pastures, and cropping systems. Overall, 60% and 51% of responses of soil macrofauna and microbial community attributes (i.e., abundance, biomass, richness, and diversity indexes) to deforestation were negative, respectively. We found few studies on mesofauna (e.g., microarthropods) and microfauna (e.g., protozoa and nematodes), so those groups could not be analyzed. Macrofauna abundance and biomass were more vulnerable to the displacement of forests by pastures than by agricultural fields, whereas microbes showed the opposite pattern. Effects of Amazonian deforestation on macrofauna were more detrimental at sites with mean annual precipitation >1900 mm, and higher losses of microbes occurred in highly acidic soils (pH < 4.5). Limited geographic coverage, omission of meso- and microfauna, and low taxonomic resolution were main factors impairing generalizations from the data set. Few studies assessed the impacts of within-forest disturbance (wildfires and selective logging) on soil species in Amazonia, where logging operations rapidly expand across public lands and more frequent severe dry seasons are increasing the prevalence of wildfires.

Deforestación en el Amazonas y Biodiversidad del Suelo Resumen Actualmente, el despeje y la perturbación de los bosques del Amazonas son las principales amenazas para la conservación de la biodiversidad tropical. Se requiere urgentemente de un mejor entendimiento sobre cómo las comunidades del suelo responden a la deforestación amazónica para informar a las intervenciones políticas que protegen efectivamente a la biodiversidad y a los servicios ambientales esenciales que proporciona. Evaluamos el impacto de la deforestación y la conversión del ecosistema a suelo arable sobre la biodiversidad del suelo amazónico por medio de un meta-análisis. Analizamos 274 comparaciones por pares de la biodiversidad del suelo amazónico en bosques primarios y sitios bajo diferentes etapas de deforestación y conversión de uso de suelo: bosques perturbados (incendios forestales y tala selectiva) y de corte-y-quema, pasturas, y sistemas agrícolas. En general, el 60% y el 51% de las respuestas de los atributos (es decir, abundancia, biomasa, riqueza, e índices de biodiversidad) de la macrofauna del suelo y de las comunidades microbianas ante la deforestación fueron negativas, respectivamente. Encontramos pocos estudios sobre la mesofauna (p. ej.: microartrópodos) y la microfauna (p. ej.: protozoarios y nematodos), así que estos grupos no pudieron ser analizados. La abundancia de la macrofauna y la biomasa fueron más vulnerables al desplazamiento de bosques por las pasturas que por los campos agrícolas, mientras que los microbios mostraron el patrón opuesto. Los efectos de la deforestación amazónica sobre la macrofauna fueron más dañinos en sitios con una precipitación anual media mayor a los 1,900 mm, y ocurrieron pérdidas más elevadas de microbios en suelos con una acidez alta (pH < 4.5). La cobertura geográfica limitada, la omisión de la mesofauna y la microfauna, y la baja resolución taxonómica fueron los factores principales que obstaculizaron las generalizaciones del conjunto de datos. Pocos estudios evaluaron los impactos de las perturbaciones internas del bosque (incendios forestales y tala selectiva) sobre las especies del suelo amazónico, a la vez que las operaciones de tala se expanden rápidamente en los terrenos públicos y la ocurrencia con mayor frecuencia de temporadas con sequía grave aumentan la prevalencia de los incendios forestales.

MGMT and MLH1 methylation in Helicobacter pylori-infected children and adults.

AIM: To evaluate the association between Helicobacter pylori (H. pylori) infection and MLH1 and MGMT methylation and its relationship with microsatellite instability (MSI). METHODS: The methylation status of the MLH1 and MGMT promoter region was analysed by methylation specific methylation-polymerase chain reaction (MSP-PCR) in gastric biopsy samples from uninfected or H. pylori-infected children (n = 50), from adults with chronic gastritis (n = 97) and from adults with gastric cancer (n = 92). MLH1 and MGMT mRNA expression were measured by real-time PCR and normalised to a constitutive gene (ß actin). MSI analysis was performed by screening MSI markers at 4 loci (Bat-25, Bat-26, D17S250 and D2S123) with PCR; PCR products were analysed by single strand conformation polymorphism followed by silver staining. Statistical analyses were performed with either the χ(2) test with Yates continuity correction or Fisher's exact test, and statistical significance for expression analysis was assessed using an unpaired Student's t-test. RESULTS: Methylation was not detected in the promoter regions of MLH1 and MGMT in gastric biopsy samples from children, regardless of H. pylori infection status. The MGMT promoter was methylated in 51% of chronic gastritis adult patients and was associated with H. pylori infection (P < 0.05); this region was methylated in 66% of gastric cancer patients, and the difference in the percentage of methylated samples between these patients and those from H. pylori-infected chronic gastritis patients was statistically significant (P < 0.05). MLH1 methylation frequencies among H. pylori-infected and non-infected chronic gastritis adult patients were 13% and 7%, respectively. We observed methylation of the MLH1 promoter (39%) and increased MSI levels (68%) in samples from gastric cancer patients in comparison to samples from H. pylori-infected adult chronic gastritis patients (P < 0.001 and P < 0.01, respectively). The frequency of promoter methylation for both genes was higher in gastric cancer samples than in H. pylori-positive chronic gastritis samples (P < 0.05). The levels of MLH1 and MGMT mRNA were significantly reduced in chronic gastritis samples that were also hypermethylated (P < 0.01). CONCLUSION: In summary, MGMT and MLH1 methylation did not occur in earlier-stage H. pylori infections and thus might depend on the duration of infection.

Identification of Chromobacterium violaceum genes with potential biotechnological application in environmental detoxification.

Chromobacterium violaceum is a Gram-negative bacterium found in a wide variety of tropical and subtropical ecosystems. The complete genome sequence of C. violaceum ATCC 12472 is now available, and it has considerable biotechnological potential for various applications, such as environmental detoxification, as well as medical and agricultural use. We examined the biotechnological potential of C. violaceum for environmental detoxification. Three operons, comprising the ars operon, involved in arsenic resistance, the cyn operon, involved in cyanate detoxification, and the hcn operon, encoding a cyanase, responsible for biogenic production of cyanide, as well as an open reading frame, encoding an acid dehalogenase, were analyzed in detail. Probable catalytic mechanisms for the enzymes were determined, based on amino acid sequence comparisons and on published structural information for these types of proteins.