Biogeography of polypores in Malesia, Southeast Asia

Wallace's line structures seagrass microbiota and is a potential barrier to the dispersal of marine bacteria

BACKGROUND

The processes that shape microbial biogeography are not well understood, and concepts that apply to macroorganisms, like dispersal barriers, may not affect microorganisms in the same predictable ways. To better understand how known macro-scale biogeographic processes can be applied at micro-scales, we examined seagrass associated microbiota on either side of Wallace's line to determine the influence of this cryptic dispersal boundary on the community structure of microorganisms. Communities were examined from twelve locations throughout Indonesia on either side of this theoretical line.

RESULTS

We found significant differences in microbial community structure on either side of this boundary (R2 = 0.09; P = 0.001), and identified seven microbial genera as differentially abundant on either side of the line, six of these were more abundant in the West, with the other more strongly associated with the East. Genera found to be differentially abundant had significantly smaller minimum cell dimensions (GLM: t923 = 59.50, P < 0.001) than the overall community.

CONCLUSION

Despite the assumed excellent dispersal ability of microbes, we were able to detect significant differences in community structure on either side of this cryptic biogeographic boundary. Samples from the two closest islands on opposite sides of the line, Bali and Komodo, were more different from each other than either was to its most distant island on the same side. We suggest that limited dispersal across this barrier coupled with habitat differences are primarily responsible for the patterns observed. The cryptic processes that drive macroorganism community divergence across this region may also play a role in the bigeographic patterns of microbiota.

Two new species of <i>Fulvifomes</i> (<i>Basidiomycota</i>, <i>Hymenochaetaceae</i>) on threatened or near threatened tree species in Japan

We describe two new species of Fulvifomes based on morphological observations and phylogenetic investigations. Both species were identified as Phellinus rimosus by former mycologists, but both are morphologically distinct from authenticated specimen of P. rimosus. Fulvifomes boninensis is characterized by perennial basidiomata, a sulcate pileus surface becoming rimose, lack of a distinct crust on the pileus surface, subdimitic hyphal system in the context, and ellipsoid basidiospores. This species is endemic to the Bonin Islands, Japan, and is specific to the host Morus boninensis, a red-listed tree species. Fulvifomes imazekii is characterized by perennial basidiomata, sulcate and velutinous pileus surface, lack of a crust on the pileus surface, dimitic hyphal system in the context, and broadly ellipsoid basidiospores. This species is specific to Berchemiella berchemiaefolia, and is known only from Mt. Yokogura-yama, in Kochi Prefecture, Japan. Fulvifomes boninensis and F. imazekii are considered threatened, because of their high host specificity each with a threatened tree species as well as the limited distribution of the former and the extremely small number of "mature individuals" of the latter. The following new combinations were also proposed: Fulvifomes aulaxinus, F. pappianus, and F. tepperi.

Composition characterization, antioxidant capacities and anti-proliferative effects of the polysaccharides isolated from Trametes lactinea (Berk.) Pat

This study was designed to investigate the chemical characterization and bioactivity of the Trametes lactinea (Berk.) Pat polysaccharides (TLP). The crude TLP was fractionated into two fractions, namely TLP-1 and TLP-2 with Cellulose DEAE-52 and Sephadex G-150. HPLC and FT-IR analysis showed that TLP-1 and TLP-2 were heteropolysaccharides mainly composed of glucose with the average molecular weights of 443.19kDa and 388.83kDa, respectively. TLP-1 from water elution possessed of higher reducing power and scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide radical and hydroxyl radical than TLP-2 eluted by 0.1M of NaCl. In comparison with TLP-2, TLP-1 showed stronger growth inhibition against human hepatoblastoma HepG-2 cells and caused higher LDH leakage. However, TLP-1 showed lower growth inhibition against normal hepatocyte L-02 cells and lower LDH leakage than TLP-2. Flow cytometric analysis showed that TLP-1 had a stimulatory effect on apoptosis of HepG-2 cells. These findings suggested that the polysaccharides, especially TLP-1 could contribute to the potential anticancer effects of T. lactinea (Berk.) Pat, which might be valuable as a natural antioxidant source applied in both healthy medicine and food industry for health benefits.