The rumen is a complex ecosystem enriched for microorganisms able to degrade biomass during the animal's digestion process. The recovery of new enzymes from naturally evolved biomass-degrading microbial communities is a promising strategy to overcome the inefficient enzymatic plant destruction in industrial production of biofuels. In this context, this study aimed to describe the bacterial composition and functions in the sheep rumen microbiome, focusing on carbohydrate-active enzymes (CAE). Here, we used phylogenetic profiling analysis (inventory of 16S rRNA genes) combined with metagenomics to access the rumen microbiome of four sheep and explore its potential to identify fibrolytic enzymes. The bacterial community was dominated by Bacteroidetes and Firmicutes, followed by Proteobacteria. As observed for other ruminants, Prevotella was the dominant genus in the microbiome, comprising more than 30 % of the total bacterial community. Multivariate analysis of the phylogenetic profiling data and chemical parameters showed a positive correlation between the abundance of Prevotellaceae (Bacteroidetes phylum) and organic matter degradability. A negative correlation was observed between Succinivibrionaceae (Proteobacteria phylum) and methane production. An average of 2 % of the shotgun metagenomic reads was assigned to putative CAE when considering nine protein databases. In addition, assembled contigs allowed recognition of 67 putative partial CAE (NCBI-Refseq) representing 12 glycosyl hydrolase families (Pfam database). Overall, we identified a total of 28 lignocellulases, 22 amylases and 9 other putative CAE, showing the sheep rumen microbiome as a promising source of new fibrolytic enzymes.
Eucalyptus rust caused by Puccinia psidii is responsible for losses of approximately 20% of young Eucalyptus plants, depending on the environmental conditions and the geographic location. Despite its economic importance, there are few studies describing the genetic variability in P. psidii populations that infect different host plants. In the present study, we evaluated the ribosomal DNA internal transcribed spacer region (rDNA-ITS) using polymerase chain reaction denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism to assess the genetic variability in P. psidii populations infecting different Eucalyptus spp. and hybrids, as well as guava, jabuticaba, and syzygium. These culture-independent methods were efficient in differentiating populations based on the host species from which they were collected. In general, the results from both techniques showed that the populations collected from guava, jabuticaba, and syzygium were different from and had a greater level of diversity than the Eucalyptus rust populations. The sequencing of cloned rDNA-ITS fragments confirmed that the vast majority of the profiles generated were from P. psidii. This analysis also revealed interesting single-nucleotide polymorphisms. Therefore, these culture-independent methods are suitable for the rapid assessment of genetic variability within and between populations of this biotrophic fungus on a variety of host species and could be a tool to study the evolution of this pathogen and its interactions with host plants.
The mating behavior of the coffee berry borer, Hypothenemus hampei (Ferrari), was observed under laboratory conditions. Pairs of adult virgin male and female beetles were placed in the wells of a polystyrene microtiter plate, one pair per well. The mating activity of each pair was recorded for 24 h. The mating behavior of the coffee berry borer was similar to that of other Scolytinae and was clearly divided into precopulatory, copulatory and postcopulatory phases. The beetles started to mate within a few hours of emergence. Repeated mating occurred during the 24-hour period and increased in frequency with age. However, we cannot address multiple matings in H. hampei, since we did not simulate the female-biased sex ratio of this species and the experimental design did not allow females to avoid additional mating attempts by males. In addition, further studies are necessary that focus on the effectiveness of sperm transmission and direct and indirect effects of multiple matings on the H. hampei females and their offspring.
The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of the Atlantic Rainforest in Brazil. Based on the comparison of three areas located along an altitudinal gradient—namely, Santa Virginia, Picinguaba and Restinga—we detected the most abundant groups of Bacteria (Acidobacteria and Proteobacteria) and Archaea (Thaumarchaeota, Crenarchaeota and Euryarchaeota). The particular composition of such communities in each of these areas was first evidenced by PCR-DGGE patterns [determined for Bacteria, Archaea and ammonia-oxidizing organisms—ammonia-oxidizing archaea (AOA) and bacteria (AOB)]. Moreover, sequence-based analysis provided a better resolution of communities, which indicated distinct frequencies of archaeal phyla and bacterial OTUs across areas. We found, as indicated by the Mantel test and multivariate analyses, a potential effect of the flora composition that outpaces the effect of soil characteristics (either physical and chemical) influencing the assembly of these microbial communities in soils. Our results indicate a collective role of the ecosystem underlying observed differences in microbial communities in these soils. Particularly, we posit that rainforest preservation also needs to take into account the maintenance of the soil biodiversity, as this is prompted to influence major processes that affect ecosystem functioning.
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