The worldwide-distributed aquatic fungus Articulospora tetracladia Ingold is a dominant sporulating species in streams of the Northwest Iberian Peninsula. To elucidate the genetic diversity of A. tetracladia, we analyzed isolates collected from various types of plant litter or foam in streams from North and Central Portugal and North Spain, between 2000 and 2010. Genetic diversity of these fungal populations was assessed by denaturing gradient gel electrophoresis (DGGE) fingerprints and by using ITS1-5.8S-ITS2 barcodes. Moreover, ITS1-5.8S-ITS2 barcodes of A. tetracladia reported in other parts of the world (Central Europe, United Kingdom, Canada, Japan and Malaysia) were retrieved from the National Center for Biotechnology (NCBI) and the National Institute of Technology and Evaluation Biological Resource Center (NBRC) to probe into genetic diversity of A. tetracladia. PCR-DGGE of ITS2 region of 50 Iberian fungal isolates distinguished eight operational taxonomic units (OTUs), which were similar to those obtained from neighboring trees based on ITS2 gene sequences. On the other hand, ITS1-5.8S-ITS2 barcodes of 68 fungal isolates yielded nine OTUs, but five fungal isolates were not assigned to any of these OTUs. Molecular diversity was highest for OTU-8, which included only European isolates. Two haplotypes were observed within OTU-8 and OTU-9, while only one haplotype was found within each of the remaining OTUs. Malaysia did not share haplotypes with other countries. Overall results indicate that, apart from the Malaysian genotypes, A. tetracladia genotypes were geographically widespread irrespective of sampling time, sites or substrates. Furthermore, PCR-DGGE appeared to be a rapid tool for assessing intraspecific diversity of aquatic hyphomycetes.
Bacteria of the genus Bartonella have been known as emerging zoonotic pathogens for several human diseases including cat scratch disease, Carrion's disease and trench fever. Numerous species of small mammals have been reported to play a role as a suitable reservoir to many pathogenic Bartonella. These infections are thought to be transmitted through blood-feeding arthropod vectors such as ticks, fleas and lice. The purpose of this study is to detect the presence of Bartonella species from tick samples collected from small mammals in mangrove forests of Peninsular Malaysia. Herein, 38 individual ticks and their small mammals host were evaluated for the presence of Bartonella DNA by conventional PCR targeting the 16S rRNA intergenic spacer region (ITS) and partial sequencing of 460 bp from this locususing Bartonella genus-specific primers. Two tick individuals from Dermacentor auratus and Haemaphysalis hystricis collected from Rattus tiomanicus (host), were PCR-positive for Bartonella DNA amplification. No Bartonella amplification was possible in other tick species (Amblyomma sp.). Phylogenetic analysis of ITS fragments demonstrated that the sequences from ticks were closely related to Bartonella phoceensis, a species that has been reported from black rats (Rattus rattus) in Australia. This is the first report of a Bartonella bacteria detected in ticks from small mammals in Malaysia. Further research should be warranted to investigate the transmission of Bartonella and the potential impact of this zoonotic pathogen in animals and humans as this mangrove ecosystem is significant for local economy and tourism.
Comparing the functional gene composition of soils at opposite extremes of environmental gradients may allow testing of hypotheses about community and ecosystem function. Here, we were interested in comparing how tropical microbial ecosystems differ from those of polar climates. We sampled several sites in the equatorial rainforest of Malaysia and Brunei, and the high Arctic of Svalbard, Canada, and Greenland, comparing the composition and the functional attributes of soil biota between the two extremes of latitude, using shotgun metagenomic Illumina HiSeq2000 sequencing. Based upon "classical" views of how tropical and higher latitude ecosystems differ, we made a series of predictions as to how various gene function categories would differ in relative abundance between tropical and polar environments. Results showed that in some respects our predictions were correct: the polar samples had higher relative abundance of dormancy related genes, and lower relative abundance of genes associated with respiration, and with metabolism of aromatic compounds. The network complexity of the Arctic was also lower than the tropics. However, in various other respects, the pattern was not as predicted; there were no differences in relative abundance of stress response genes or in genes associated with secondary metabolism. Conversely, CRISPR genes, phage-related genes, and virulence disease and defense genes, were unexpectedly more abundant in the Arctic, suggesting more intense biotic interaction. Also, eukaryote diversity and bacterial diversity were higher in the Arctic of Svalbard compared to tropical Brunei, which is consistent with what may expected from amplicon studies in terms of the higher pH of the Svalbard soil. Our results in some respects confirm expectations of how tropical versus polar nature may differ, and in other respects challenge them.