摘要: High-mountain stream ecosystems are recognized as ideal arenas for natural experiments and for ecological monitoring and assessment research, owing to their sensitivity to climate gradients and human-mediated disturbances. In this study, we chose a subtropical mountainous stream system in southwestern China, to explore the spatiotemporal patterns and driving factors of taxonomic, phylogenetic, and functional beta diversity of macro-invertebrate assemblages. We found that taxonomic beta diversity was highest (on average, 0.577 in spring and 0.645 in autumn) across seasons, followed by phylogenetic (0.491 and 0.545) and functional (0.350 and 0.383) beta diversity, with the replacement component predominantly (57%-73%) contributing to all three facets of diversity. The taxonomic local contributions to beta diversity (LCBD) values were roughly equivalent among different sites in both spring and autumn, whereas phylogenetic LCBD (PLCBD) and functional LCBD (XLCBD) indices varied from site to site. Therefore, we recommend prioritizing site conservation based on LCBD, PLCBD, and XLCBD values to optimize biodiversity conservation strategies. The three-facets of dissimilarities were all somewhat higher in autumn than spring, possibly due to recolonization events in the metacommunity after the summer flood. Variation partitioning analysis indicated that environmental factors were more important than spatial factors in structuring all three facets of beta diversity and their components, although different sets of variables were identified as important for different diversity facets and between seasons. In summary, our study offers valuable insights into the patterns and drivers of macroinvertebrate beta diversity in high mountain streams and lays a baseline for targeted conservation strategies in these ecosystems.

摘要: On 29 January 2024, a truck accident spilled concentrated sulfonic acid into a river in Brazil's State of Santa Catarina. This disaster, which occurred in a protected area, killed various types of fish (e.g., crenuchids, heptapterids, and loricariids) and probably many other less observable animals, such as small invertebrates. The accident, similar to others around the world, gained national and international media attention. Because truck accidents causing aquatic pollution through chemical spills are occurring not just in Brazil but also globally, the recent event led us to consider similar cases and to recommend potential measures to help mitigate biodiversity loss in waterbodies near roads. Three factors need to be considered: (i) human (drivers); (ii) truck (mechanical condition); and (iii) road (e.g., infrastructure). In addition, improved expert assessments of the negative impact of these accidents on biodiversity are needed. A requirement to aid recovery of polluted ecosystems should be incumbent upon the companies involved in truck accidents.

摘要: Parkinson's disease (PD) is the second most common neurodegenerative disease. Potassium voltage-gated channels are potential targets for the treatment of PD. The aim of this study is to identify novel potassium ion channel blockers for the treatment of PD through transcriptomic analysis of the coral species Galaxea fascicularis. After annotation by four different databases, four peptides were selected that showed characteristics of potassium ion channel blockers. These four peptides were subjected to multiple sequence alignment and phylogenetic analysis. These four peptides were identified as of Kunitz-type peptides, are known as potassium ion channel blockers. The structures of the peptides were modeled and subjected to molecular dynamics (MD) simulation to verify their stability, which indicated that the peptide GfKuz1 showed the highest potency to block KV1.3 (potassium voltage-gated channel subfamily A member 3) among the reference peptides. The MD simulation of the peptide-protein complexes showed that GfKuz1 interacted with KV1.3, and was more compact and stable than the other potassium ion channel. The blocking effect was confirmed by a potassium ion bioassay. Furthermore, GfKuz1 showed no toxicity to PC-12 cells or zebrafish at concentrations up to 100 mu M. In addition, GfKuz1 increased the PC-12 cell viability that was reduced by 6-hydroxydopamine hydrochloride, and also down-regulated the level of reactive oxygen species and activated the Nrf2 pathway. In summary, GfKuz1 reversed PD symptoms and is a potential peptide drug prototype for PD treatment.

摘要: Water stratification is a prominent oceanographic phenomenon in the North Yellow Sea, a vital region for mollusk aquaculture in northern China. Understanding the influences of water stratification on planktonic bacterial communities in those waters is crucial for the sustainable development of mollusk aquaculture in this region. In the present study, the bacterial community profiles across different water layers in a representative Yesso scallop farming area of Zhangzi Island in the North Yellow Sea were surveyed from March 2021 to January 2022. Water stratification was present in June, July, and August (the stratification period, abbreviated as S period) and absent in March, October, and January (the mixing period, abbreviated as M period), based on the vertical distribution of water temperatures. Results of the 16S rRNA gene sequencing showed that the alpha diversity of bacterial communities in the S period (Chao1 index: 500.78, Shannon index: 6.85) was significantly lower than in the M period (Chao1 index: 575.00, Shannon index: 7.24). The relative abundances of Synechococcus CC9902 and Vibrio were significantly higher in the S period compared to the M period, while the abundance of Clade Ia showed the opposite trend. Water temperature, salinity, and dissolved inorganic nitrogen were identified as the main environmental drivers of the bacterial communities, which accounted for 22.4%, 20.0%, and 17.1%, respectively, of the total variation in bacterial community composition. Functional prediction suggested that the pathways associated with cytochrome biosynthesis and nutrient utilization of the bacterial communities were significantly enriched in the S period, while those involved in energy metabolism were enhanced in the middle and bottom layers compared to the surface layer during the S period. The connectivity of the molecular ecological network increased in the S period, with the number of edges, average degree, and average clustering coefficient being 574, 11.36, and 0.57 in the S period and 524, 9.44, and 0.51 in the M period, respectively. Collectively, these results indicated that water stratification led to a decrease in bacterial community diversity and an increase in the relative abundance of Synechococcus CC9902 and Vibrio, which were potentially detrimental to mollusk health and aquaculture. Our results contribute to clarifying the dynamics of planktonic bacterial communities and their impacts on mollusk aquaculture in the context of intensifying ocean stratification.

摘要: The adaptive strategies of prey against predation risk have been pivotal in non-consumptive effects. However, the adaptive strategies of prey and the response mechanisms to various predation risk cues remain unclear. We hypothesized that prey adopt a similar adaptive strategy to address different predation risks, but their response mechanisms depend on the attributes of predation risk cues. To test this hypothesis, we used Didinium-Paramecium as a predator-prey model to first evaluate the effects of various predation risk cues, including homogenates of predators (TD) and prey (TP) alone or in combination (TM), and the density of conspecific prey on the specific growth rate (SGR) to determine their adaptive strategies and their underlying response mechanisms based on transcriptomic analysis. Our results show that predation risk cues considerably enhance prey SGR, with effects in descending order of TM, TD, and TP. However, such effects gradually decrease as the density of conspecific prey increases until they disappear. The trend in the levels of differentially expressed genes (DEGs) in prey exposed to different predation risk cues is similar to that of SGRs. In particular, pathways based on DEG enrichment mediated by predation risk cues involve cellular processes, nutrient metabolism, and synthesis of biological macromolecules. However, they differ in type, number, and location within specific biological processes. In conclusion, Paramecium uses early reproduction strategies to address the risk of predation caused by different cues, and differences in its response mechanisms depend on the attributes of the cues of predation risk, resulting in differences in the SGR of the prey.

摘要: Life history theory predicts that species-specific life history traits are shaped by variations in environmental conditions. Understanding the key environmental factors determining life history strategies can provide insights into the mechanisms of community assembly and identify potential biodiversity threats by predicting selective responses to environmental perturbations. We collected life history traits for fish species from 14 river basins across 5 continents to identify their life history strategies and explore the related key environmental factors. Our results showed that fishes from all the river basins conformed to a triangular life history strategy model including periodic, opportunistic, and equilibrium endpoints. However, the proportions of these three strategies varied significantly amongst river basins. For example, the Rhine River basin had a high proportion of fish with the periodic strategy and a low proportion of fish with the opportunistic strategy, whereas the Mississippi River basin displayed the opposite pattern. At the river basin extent, linear regression analysis revealed that the proportion of species with the opportunistic strategy increased with mean annual temperature, annual variation in river discharge, and annual precipitation, and was negatively associated with latitude. In contrast, species with the periodic strategy were negatively related to annual variation in river discharge and positively with latitude. These findings corroborate that opportunistic species are adapted to unpredictable environments, whereas periodic species are adapted to predictable environments. We then used molecular phylogeny to reconstruct the ancestral state of Yangtze fishes and analyzed the percentage composition of the three life history strategies across geological times. We found dominance of the equilibrium strategy in the Upper Cretaceous followed by dominance of periodic fishes before the Paleocene. Opportunistic fish species began to dominate the Yangtze River basin after the Miocene, with more than half of the fish species being opportunistic. This implies that the environmental conditions in the Yangtze River basin evolved from stable (low annual variation in river discharge) to unstable (high annual variation in river discharge and high annual precipitation) states, possibly associated with the onset of seasonality expressed as prevalence of a monsoon climate and the overall alteration of precipitation patterns. Life history theory can give hints for assessing river ecological conditions because changes in strategy proportions may indicate the alteration of environmental conditions. Such changes can aid in developing suitable strategies for river ecological protection and fish resource management.

摘要: The genus Neophocaena includes two species, the Indo-Pacific finless porpoise (N. phocaenoides) and the Narrowridged finless porpoise (N. asiaeorientalis). The Indo-Pacific species is found in coastal waters from the Persian Gulf through south and southeast Asia to as far north as the Taiwan Strait. The Narrow-ridged finless porpoise ranges from the Taiwan Strait to the waters of northern China, Korea, and Japan. Within N. asiaeorientalis there are two subspecies, the Yangtze finless porpoise (N. a. asiaeorientalis), found in the Yangtze River and adjoining lakes in China, and the East Asian finless porpoise (N. a. sunameri), found in coastal marine waters of China (including Hong Kong and Taiwan), Korea, and Japan. In 2019, an international workshop was held on finless porpoise research and conservation. Participants shared that, in many regions, information on distribution, abundance and population structure is lacking or inadequate. A global assessment of research is critical to provide a basis for conservation planning. Anthropogenic activities (i.e., habitat degradation, pollution, etc.) are known threats, with fisheries bycatch the primary threat throughout the known distribution of finless porpoises. To conserve these cetaceans, research priorities include studies of abundance and distribution, habitat and ecology, fisheries-related mortality, increased public awareness, and bycatch mitigation.

摘要: The invasive aquatic plant Pontederia crassipes (water hyacinth) presents significant ecological and economic challenges worldwide due to its rapid proliferation and dominance in freshwater ecosystems. This review synthesizes the multifaceted aspects of P. crassipes, from its ecological impacts to its potential applications, highlighting sustainable management strategies. Despite its invasiveness, P. crassipes exhibits remarkable potential in phytoremediation, biofuel production, biomaterial synthesis, and agricultural uses. Its ability to absorb pollutants, including heavy metals and nutrients, renders it valuable for environmental remediation. The conversion of P. crassipes into biochar, bioplastics, and industrial products aligns with circular economy principles, promoting resource recovery and environmental conservation. However, while these applications are promising in theory, real-world evidence demonstrating the successful mitigation of P. crassipes' invasive potential through such methods remains minimal. Few case studies and field trials have shown positive impacts, underscoring the need for further research before conclusive recommendations can be made. Traditional management methods, such as mechanical, chemical, and biological controls, face limitations including labor intensity, environmental safety concerns, and ecological impacts. An integrated approach that combines these strategies is essential for effective management. Future research should prioritize large-scale case studies to evaluate the practical viability of these sustainable applications and their long-term ecological effects, ultimately repurposing P. crassipes from an invasive species into a valuable resource for global environmental sustainability.

摘要: Two populations of the kentrurostylid ciliate Pseudokeronopsis erythrina Chen et al., 2011 were isolated from a brackish wastewater treatment plant, Pisa, Italy and from a nutrient-rich freshwater body, the East Lake, Wuhan, China. The populations were thoroughly investigated for their morphology, focusing on cell body plasticity. The study was supplemented with 18S rDNA phylogenetic analysis and mitogenome sequencing, following the integrative taxonomy approach. The Italian population possesses a great variation in terms of the frontal area, and the numbers of left marginal rows, and dorsal kineties. Additionally, the number of left marginal anlagen and dorsal kineties anlagen varied. For instance, additional small anlagen appeared in the left marginal rows, and two dorsal kineties anlagen derived from a single dorsal kinety. The Wuhan population resembled the type population (originally isolated from Guangzhou, China), differing only by the presence of an extra dorsal kinety. The existence of giant individuals characterized both new populations of P. erythrina although with some differences in their respective frequency and features. The 18S rDNA sequences of the Italian, Wuhan, and type populations were identical. Phylogenetic analyses showed that these three populations formed a distinct cluster within the clade containing P. songi, P. parasongi, and P. flava. The structure of the P. erythrina mitochondrial genome is also provided. The content of this genome closely resembled Pseudourostyla cristata, except for the absence of genes nadh3 and nadh6. Our findings suggest that the Wuhan population represents an intermediate form between the type and Italian populations. The greater morphological plasticity observed in the Italian population underscores the importance of molecular data and integrative analyses in species identification.

摘要: Competing endogenous RNAs (ceRNAs) are a novel epigenetic regulatory mechanism implicated in sex determination and differentiation in teleosts, which exhibit a diversity of sex-determining mechanisms. In this study, based on whole transcriptome sequencing data, a ceRNA regulatory network composed of sex-inclined miRNAs (miR-456), lncRNAs (ASTR), circRNAs (circklhl29), and target mRNAs (spire1 and sox11) was uncovered in the gonadal tissues of Seriola dumerili, an oceanic species with lagged gonadal development. MiRNA-456 was identified as the core of the ceRNA regulatory network and suppressed the expression of spire1 and sox11, interacting with the ncRNAs including circklhl29 and ASTR. Co-localization of these sex-biased ncRNAs and mRNAs in the gonads suggests that this ceRNA network modulated the gonadal differentiation in both sexes of S. dumerili. In vivo injection in the gonads of S. dumerili suggested the miR-456 agonist could significantly inhibit expression of sox11 and spire1 in male testes, while significant regulatory effects of the miR-456 agonist and antagonist on sox11 and spire1 targets were not observed in female ovaries. The conserved binding sites for sequences of miR-456 and spire1/sox11 targets in various fish species were aligned and dual luciferase reporter gene experiments clarified the universality of the mechanism by which miR-456 bound to inhibit sox11/spire1 targets in large yellow croaker (Larimichthys crocea), half-smooth tongue sole (Cynoglossus semilaevis), and zebrafish (Danio rerio). These results further support the notion that ceRNA networks may be a universal regulatory system in teleosts despite their highly divergent sex regulation programs.