A Molecular Phylogeny of the Lichen Genus Lecidella Focusing on Species from Mainland China

The phylogeny and taxonomy of Glypholecia (Acarosporaceae, lichenized Ascomycota), including a new species from northwestern China

Glypholeciaqinghaiensis An C. Yin, Q. Y. Zhong & Li S. Wang is described as new to science. It is characterized by its squamulose thallus, compound apothecia, ellipsoid ascospores, and the presence of rhizines on the lower surface of the thallus. A phylogenetic tree of Glypholecia species was constructed based on nrITS and mtSSU sequences. Two species G.qinghaiensis and G.scabra are confirmed in China.

Fruticose Lichen Communities at the Edge: Distribution and Diversity in a Desert Sky Island on the Colorado Plateau

Subalpine habitats in sky islands in the Southwestern USA are currently facing large-scale transformations. Lichens have widely been used as bioindicators of environmental change. On the Colorado Plateau, fruticose lichens occur in patchy, disconnected populations, including unique lichen-draped conifer sites in subalpine forests in the La Sal Mountains in southeastern Utah. Here, we document the distribution and fungal diversity within these lichen communities. We find that lichen-draped conifer sites in the La Sal Mountains are restricted to only three known, small areas in Picea englemannii forests above 3000 m above sea level, two of which have recently been impacted by wildfire. We document 30 different species of lichen-forming fungi in these communities, several which represent the first reports from the Colorado Plateau. We also characterize mycobiont haplotype diversity for the fruticose lichens Evernia divaricata, Ramalina sinensis, and multiple Usnea species. We also report a range of diverse fungi associated with these lichens, including genetic clusters representing 22 orders spanning seven classes of Ascomycetes and fewer clusters representing Basidiomycetes. Our results provide a baseline for ongoing monitoring and help to raise awareness of unique lichen communities and other biodiversity in the region.

High levels of endemism and local differentiation in the fungal and algal symbionts of saxicolous lecideoid lichens along a latitudinal gradient in southern South America

Saxicolous, lecideoid lichenized fungi have a cosmopolitan distribution but, being mostly cold adapted, are especially abundant in polar and high-mountain regions. To date, little is known of their origin or the extent of their trans-equatorial dispersal. Several mycobiont genera and species are thought to be restricted to either the Northern or the Southern Hemisphere, whereas others are thought to be widely distributed and occur in both hemispheres. However, these assumptions often rely on morphological analyses and lack supporting molecular genetic data. Also unknown is the extent of regional differentiation in the southern polar regions. An extensive set of lecideoid lichens (185 samples) was collected along a latitudinal gradient at the southern end of South America. Subantarctic climate conditions were maintained by increasing the elevation of the collecting sites with decreasing latitude. The investigated specimens were placed in a global context by including Antarctic and cosmopolitan sequences from other studies. For each symbiont three markers were used to identify intraspecific variation (mycobiont: ITS, mtSSU, RPB1; photobiont: ITS, psbJ-L, COX2). For the mycobiont, the saxicolous genera Lecidea, Porpidia, Poeltidea and Lecidella were phylogenetically re-evaluated, along with their photobionts Asterochloris and Trebouxia. For several globally distributed species groups, the results show geographically highly differentiated subclades, classified as operational taxonomical units (OTUs), which were assigned to the different regions of southern South America (sSA). Furthermore, several small endemic and well-supported clades apparently restricted to sSA were detected at the species level for both symbionts.

Squamarina (lichenised fungi) species described from China belong to at least three unrelated genera

New collections of six Squamarina species from type localities in China were studied. The comparison of morphological characteristics and secondary metabolites with those of the type specimens and phylogenetic analyses suggest that S. callichroa and S. pachyphylla belong to Rhizoplaca, S. semisterilis belongs to Lobothallia and S. chondroderma should be retained in Lecanora temporarily. Only two species, S. kansuensis and S. oleosa, remain in Squamarina. The new combinations Lobothallia semisterilis (H. Magn.) Y. Y. Zhang, Rhizoplaca callichroa (Zahlbr.) Y. Y. Zhang and R. pachyphylla (H. Magn.) Y. Y. Zhang are proposed. Detailed descriptions to aid the identification of these species, distributions and phylogenetic trees, based on multiple collections, are presented. The generic concept of Squamarina is recircumscribed in this study.

Survival Mechanisms to Selective Pressures and Implications

Organisms have evolved a spectrum of strategies that facilitate survival in the face of adverse environmental conditions. In order to make full use of the unfavorable resources of nature, human beings usually impose selective pressures to breed phenotypic traits that can survive in adverse environments. Animals are frequently under attack by biotic stress, such as bacterial and viral infections, while plants are more often subjected to abiotic stress, including high salinity, drought, and cold. In response to these diverse stresses, animals and plants initiate wide-ranging changes in gene expression by altering regulation of transcriptional and post-transcriptional activities. Recent studies have identified a number of key responsive components that promote survival of animals and plants in response to biotic and abiotic stresses. Importantly, with recent developments in genome-editing technology based on the CRISPR/Cas9 system, manipulation of genetic elements to generate stress-resistant animals and plants has become both feasible and cost-effective. Herein, we review important mechanisms that govern the response of organisms to biotic and abiotic stresses with the aim of applying our understanding to the agriculture and animal husbandry industries.

Histone deacetylase 6 modulates macrophage infiltration during inflammation

Mice with histone deacetylase 6 (HDAC6) deficiency grow and develop normally but exhibit impaired immune response. The molecular mechanisms for this phenotype remain largely elusive.

Methods: A mouse acute peritonitis model was used to study the infiltration of neutrophils and monocyte-derived macrophages. In vitro cell motility assays were performed to analyze monocyte/macrophage recruitment. Fluorescence microscopy and flow cytometry were performed to examine the phagocytic ability of macrophages. Immunofluorescence microscopy was used to investigate protein localization, protrusion formation, and microtubule acetylation.

Results: HDAC6 deficiency does not affect neutrophil infiltration, but instead attenuates the infiltration of monocyte-derived macrophages into the peritoneal cavity. HDAC6 plays a specific role in monocyte/macrophage recruitment. Loss of HDAC6 suppresses the phagocytic capacity of macrophages challenged with E. coli. Lipopolysaccharide stimulation results in the translocation of HDAC6 and cortactin from the cytosol to the cell periphery, promotes the formation of filopodial protrusions, and enhances microtubule acetylation around the microtubule-organizing center, all of which are abrogated by HDAC6 deficiency.

Conclusion: These findings implicate HDAC6 in the innate immune response and suggest that it may serve as a promising target for the treatment of macrophage-associated immune diseases.

Molecular mechanisms underlying stress response and adaptation

Environmental stresses are ubiquitous and unavoidable to all living things. Organisms respond and adapt to stresses through defined regulatory mechanisms that drive changes in gene expression, organismal morphology, or physiology. Immune responses illustrate adaptation to bacterial and viral biotic stresses in animals. Dysregulation of the genotoxic stress response system is frequently associated with various types of human cancer. With respect to plants, especially halophytes, complicated systems have been developed to allow for plant growth in high salt environments. In addition, drought, waterlogging, and low temperatures represent other common plant stresses. In this review, we summarize representative examples of organismal response and adaptation to various stresses. We also discuss the molecular mechanisms underlying the above phenomena with a focus on the improvement of organismal tolerance to unfavorable environments.