ABSTRACT
Microbial communities in mangrove forests have recently been intensively investigated to explain the ecosystem function of mangroves. In this study, the soil microbial communities under young (<11 years-old) and old (>17 years-old) mangroves have been studied during dry and wet seasons. In addition, biogeochemical properties of sediments and methane emission from the two different mangrove ages were measured. The results showed that young and old mangrove soil microbial communities were significantly different on both seasons. Seasons seem to affect microbial communities more than the mangrove age does. Proteobacteria and Chloroflexi were two top abundant phyla showing >15%. Physio-chemical properties of sediment samples showed no significant difference between mangrove ages, seasons, nor depth levels, except for TOC showing significant difference between the two seasons. The methane emission rates from the mangroves varied depending on seasons and ages of the mangrove. However, this did not show significant correlation with the microbial community shifts, suggesting that abundance of methanogens was not the driving factor for mangrove soil microbial communities.
Subject(s)
Microbiota , Wetlands , Ecosystem , Bacteria/genetics , Seasons , Methane , Parks, Recreational , Soil/chemistryABSTRACT
BACKGROUND: The genus Charaea Baly is distributed in the eastern Palaearctic, Himalayas, China and adjacent countries of the Oriental Region. Currently, 59 species of the genus Charaea have been recorded. The species of Charaea is characterised with a robust tubular aedeagus that terminates with a more or less distinct apical process with the Charaeacoomani group having an internal sac with long sharp lateral sclerites. Up to now, 13 species of this group have been described in the Oriental Region, four of which are found in Vietnam. NEW INFORMATION: Charaeadinhcuongi sp. nov. is described as a new species, based on specimens collected from Phu Quoc Island in southern Vietnam. Colour photographs of habitus and body details and DNA barcode sequences are presented. An identification key is provided for all Vietnamese species from the Charaeacoomani group.
ABSTRACT
Tylosin has been used as a livestock feed additive and antibiotic growth promoter for many years. However, the mode of action by which tylosin enhances animal growth is unclear. We used high-throughput sequencing of 16S rRNA genes to investigate the effects of tylosin as a feed additive on swine gut microbiota. No significant difference in the rate of weight increase was observed between control and tylosin-treated pigs during a 10-week feeding trial. However, tylosin-treated pigs showed rapid increases in the relative abundance of the phylum Firmicutes. Increases in Firmicutes species are associated with (so-called) obese-type gut microbiota. The abundance of species of four families of the phylum Firmicutes (Streptococcaceae, Peptococcaceae, Peptostreptococcaceae, and Clostridiaceae) correlated positively with host weight gain. The abundance of Streptococcaceae family bacteria was least affected by tylosin treatment. Distribution analysis of operational taxonomic units (OTUs) showed that both control and tylosin-treated pigs exhibited similar OTU alterations during growth. However, the tylosin-treated group showed distinctive alterations in gut microbiota when the host weighed approximately 60 kg, whereas similar alterations occurred at around 80 kg in the control group. Our results suggest that use of tylosin accelerates maturation of swine gut microbiota rather than altering its composition.
