Machine learning prediction on wetland succession and the impact of artificial structures from a decade of field data.

The artificial structures can influence wetland topology and sediment properties, thereby shaping plant distribution and composition. Macrobenthos composition was correlated with plant cover. Previous studies on the impact of artificial structures on plant distribution are scarce in incorporating time-series data or extended field surveys. In this study, a machine-learning-based species distribution model with decade-long observation was analyzed to investigate the correlation between the shift in the distribution of B. planiculmis, artificial structure-induced elevation changes and the expansion of other plants, as well as their connection to soil properties and crab composition dynamics under plants in Gaomei Wetland. Long short-term memory model (LSTM) with Shapley additive explanations (SHAP) was employed for predicting the distribution of B. planiculmis and explaining feature importance. The results indicated that wetland topology was influenced by both artificial structures and plants. Areas initially colonized by B. planiculmis were replaced by other species. Soil properties showed significant differences among plant patches; however, principal component analysis (PCA) of sediment properties and niche similarity analysis showed that the niche of plants was overlapped. Crab composition was different under different plants. The presence probability of B. planiculmis near woody paths decreased according to LSTM and field survey data. SHAP analysis suggested that the distribution of other plants, historical distribution of B. planiculmis and sediment properties significantly contributed to the presence probability of B. planiculmis. A sharp decrease in SHAP values with increasing NDVI at suitable elevations, overlap in PCA of sediment properties and niche similarity indicated potential competition among plants. This decade-long time-series field survey revealed the joint effects of artificial structure and vegetation on the topology and soil properties dynamics. These changes influenced the plant distribution through potential plant competition. LSTM with SHAP provided valuable insights in the underlying the mechanisms of artificial structure effects on the plant zonation process.

Cellular mechanisms underlying extraordinary sulfide tolerance in a crustacean holobiont from hydrothermal vents.

The shallow-water hydrothermal vent system of Kueishan Island has been described as one of the world's most acidic and sulfide-rich marine habitats. The only recorded metazoan species living in the direct vicinity of the vents is Xenograpsus testudinatus, a brachyuran crab endemic to marine sulfide-rich vent systems. Despite the toxicity of hydrogen sulfide, X. testudinatus occupies an ecological niche in a sulfide-rich habitat, with the underlying detoxification mechanism remaining unknown. Using laboratory and field-based experiments, we characterized the gills of X. testudinatus that are the major site of sulfide detoxification. Here sulfide is oxidized to thiosulfate or bound to hypotaurine to generate the less toxic thiotaurine. Biochemical and molecular analyses demonstrated that the accumulation of thiosulfate and hypotaurine is mediated by the sodium-independent sulfate anion transporter (SLC26A11) and taurine transporter (Taut), which are expressed in gill epithelia. Histological and metagenomic analyses of gill tissues demonstrated a distinct bacterial signature dominated by Epsilonproteobacteria. Our results suggest that thiotaurine synthesized in gills is used by sulfide-oxidizing endo-symbiotic bacteria, creating an effective sulfide-buffering system. This work identified physiological mechanisms involving host-microbe interactions that support life of a metazoan in one of the most extreme environments on our planet.

A Multi-Species Comparison and Evolutionary Perspectives on Ion Regulation in the Antennal Gland of Brachyurans.

Brachyurans inhabit a variety of habitats and have evolved diverse osmoregulatory patterns. Gills, antennal glands and a lung-like structure are important organs of crabs that maintain their homeostasis in different habitats. Species use different processes to regulate ions in the antennal gland, especially those with high terrestriality such as Grapsoidea and Ocypodoidea. Our phylogenetic generalized least square (PGLS) result also suggested that there is a correlation between antennal gland NKA activity and urine-hemolymph ratio for Na+ concentration in hypo-osmotic environments among crabs. Species with higher antennal gland NKA activity showed a lower urine-hemolymph ratio for Na+ concentration under hypo-osmotic stress. These phenomenon may correlate to the structural and functional differences in gills and lung-like structure among crabs. However, a limited number of studies have focused on the structural and functional differences in the antennal gland among brachyurans. Integrative and systemic methods like next generation sequencing and proteomics method can be useful for investigating the differences in multi-gene expression and sequences among species. These perspectives can be combined to further elucidate the phylogenetic history of crab antennal glands.

Ion regulation in the antennal glands differs among Ocypodoidea and Grapsoidea crab species.

Gills and the antennal gland are ion-regulatory organs in crabs. Previous studies have suggested that the differences in the morphology and ion regulation of gills and accessory respiratory organs between ocypodid and grapsid species are related to their distinct evolutionary transition to land habitats. In addition, Na+, K+-ATPase (NKA) activity and Na+ and NH4+ regulation in the antennal gland differ between ocypodid and grapsid species, which had different terrestrial adaptation trajectories. This study used five Ocypodoidea species and three Grapsoidea species from the intertidal and supratidal zones to further investigate the differences in ion regulation and NKA activity in the antennal gland between these crab families in different habitats. Crabs were transferred to 5 practical salinity unit (PSU) water, and osmolality, Na+ and Cl- concentrations in the urine and hemolymph, and NKA activity in the antennal gland were examined. Phylogenetic ANOVA results showed that the NKA activity in the antennal gland was higher in the ocypodid than grapsid groups, and Moran's I autocorrelation analysis also indicated that NKA activity in the antennal gland was phylogenetically correlated among crabs. K-means clustering showed a difference among the crabs in the crabs' Na+ and Cl- concentrations in the urine/hemolymph, NKA activities in the antennal gland and gill 6, and number of pairs of gills. Crabs with relatively high antennal gland NKA activity were found not only in the Ocypode species, which are better adapted to terrestrial environments, but also in two intertidal species of Gelasiminae. In conclusion, part of the Ocypodidae lineage may have a) the ability to reabsorb Na+ and b) higher NKA activity in the antennal gland than other families, and this phenomenon is phylogenetically correlated in Ocypodoidea and Grapsoidea. The physiological diversity in osmoregulation among intertidal and costal species provides a base to further investigate their ecological niches and guilds.

Complete Genome Sequence of Lignin-Degrading Streptomyces sp. Strain S6, Isolated from an Oil Palm Plantation in Malaysia.

Streptomyces spp. are bacteria that are responsible for the degradation of aromatic compounds and produce secondary metabolites. Here, we present a complete genome sequence of Streptomyces sp. strain S6, which was isolated from an oil palm plantation, with a 7.8-Mbp liner chromosome, a GC content of 72%, and 4,266 coding sequences.

Morphological and genetic characteristics of F1 hybrids introgressed from Brassica napus to B. rapa in Taiwan.

BACKGROUND: Unintentional introgression from genetically modified (GM) oilseed rape (Brassica napus) to a relative is inevitable in the open field. A feasible and practical strategy for restricting the spread of GM offspring is to set a reasonable isolated distance between GM B. napus and the relatives. To define the isolated distance, a pollen donor/recipient pair is a prerequisite to conducting the field trial of pollen flow. However, because the cultivation of GM B. napus is prohibited in Taiwan, it is difficult to obtain relevant information. Thus, this study explored the morphological and genetic characteristics of five varieties of B. napus (donor), three varieties of B. rapa (recipient), and the 15 corresponding F1 hybrids, aiming to construct phenotypic data and genetic variation data and to select the most appropriate pollen donor/recipient for future field trials of pollen flow. RESULTS: The genome size of all F1 hybrids estimated using flow cytometry showed intermediate DNA content between B. napus and B. rapa varieties. Most of the F1 hybrids had intermediate plant height and blooming period, and the rosette leaves type and colors resembled those of B. napus varieties. The results of sequence-related amplified polymorphism (SRAP) showed an average of 9.52 bands per primer combination and 67.87 polymorphic bands among the F1 hybrid population. Similarity and cluster analyses revealed higher similarity between F1 hybrids and B. napus varieties than between F1 hybrids and B. rapa varieties. Furthermore, we identified a specific 1100-bp band (LOC106302894) in F1 hybrids and B. napus varieties but not in B. rapa varieties. CONCLUSIONS: The rosette leaves and the DNA marker LOC106302894 observed in F1 hybrids are consistent phenotypic and genetic characteristics that can be used to identify the presence of unintentional hybridization from B. napus to B. rapa in Taiwan. Due to the prohibition of GM crop cultivation, the hybridization system of non-GM Brassica species in this study can be utilized as a mimic scheme to conduct pollen flow trials, thus facilitating the determination of the proper isolated distance.