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Two previously unknown species of Rhinogobius have been discovered in the streams of the Upper Youshui River, within the Yuan River Basin, Xiushan County, Chongqing, China. These new species are named as Rhinogobius sudoccidentalis and Rhinogobius lithopolychroma. Phylogenetic analysis based on mitochondrial genomes revealed that R. sudoccidentalis is genetically closest to R. reticulatus, while R. lithopolychroma shares the greatest genetic similarity with R. leavelli. Morphological distinctions allow for the clear differentiation of these species. Rhinogobius sudoccidentalis sp. nov. is characterized by having VI–VII rays in the first dorsal fin and I, 8–9 rays in the second dorsal fin. The longitudinal scale series typically consists of 22–24 scales, while the transverse scale series comprises 7–8 scales. Notably, the predorsal scale series is absent and the total vertebrae count is 12+17=29. Rhinogobius lithopolychroma sp. nov. can be distinguished from other species by the presence of 13–15 rays on the pectoral fin. Its longitudinal scale series ranges from 30 to 33 scales, with no scales in the predorsal area. The total vertebral count is 30, with 12 precaudal and 18 caudal vertebrae. The head and body of this species are light gray with irregular orange markings on the cheeks and opercle. Through morphological and molecular analyses, it has been confirmed that R. lithopolychroma and R. sudoccidentalis represent novel species within the Rhinogobius genus.

Abstract Land‒atmosphere coupling intensifies the vulnerability of ecosystems in drylands. However, whether and how ecological restoration would modify the land‒atmosphere coupling across drylands remains unclear. To address these gaps, here we use structural equation model to separate two pathways of land‒atmosphere coupling: vegetation and soil moisture pathways, and investigate the effect of ecological restoration in China’s drylands on land‒atmosphere coupling. Analysis reveals that, land‒atmosphere coupling regulates approximately 30% of atmospheric drought, among which soil moisture pathway contributes twice as much as vegetation pathway. Vegetation greening mitigates atmospheric drought in areas where the aridity index ranges from 0.3 to 0.5, while soil drying exacerbates atmospheric drought in areas where the aridity index ranges from 0.5 to 0.65. The findings identify the optimal regions where ecological restoration helps alleviate the vulnerability of ecosystems under anthropogenic warming. Additionally, the proposed method enhances the understanding of how restored ecosystems contribute to mitigating atmospheric drought.

Abstract Remora albescens, also known as white suckerfish, recognized for its distinctive suction-cup attachment behavior and medicinal significance. In this study, we produced a high-quality chromosome-level genome assembly of R. albescens through the integration of 23.87 Gb PacBio long reads, 64.54 Gb T7 short reads, and 88.63 Gb Hi-C data. Initially, we constructed a contig-level genome assembly totaling 605.30 Mb with a contig N50 of 23.12 Mb. Subsequently, employing Hi-C technology, approximately 99.68% (603.38 Mb) of the contig-level genome was successfully assigned to 23 pseudo-chromosomes. Through the integration of homologous-based predictions, ab initio predictions, and RNA-sequencing methods, we successfully identified a comprehensive set of 22,445 protein-coding genes. Notably, 96.36% (21,629 genes) of these were effectively annotated with functional information. The genome assembly achieved an estimated completeness of 98.1% according to BUSCO analysis. This work promotes the applicability of the R. albescens genome, laying a solid foundation for future investigations into genomics, biology, and medicinal importance within this species.

Gymnocypris eckloni (G. eckloni), a cold-water economic fish, is widely cultivated in southwestern China. The increase in extreme summer weather conditions owing to global warming can significantly affect their survival and health. The fish intestine and its microbiota are closely associated with fish feeding and growth, nutritional metabolism, and immune defense. However, the mechanisms underlying the changes in the G. eckloni intestine and its microbiota under acute heat stress remain unknown. In this study, we investigated the effects of acute heat stress on the G. eckloni intestine employing histology, plasma biochemical indices, transcriptomics, and 16S rDNA sequencing. Histological analysis showed that acute heat stress induced significant morphological damage to the intestine, with microvilli detachment and mitochondrial abnormalities in the ultrastructure. Biochemical indicators associated with stress (reactive oxygen species and catalase), inflammation (interleukin-1β and tumor necrosis factor-α), and intestinal permeability (diamine oxidase and lipopolysaccharide) were significantly elevated after acute heat stress, indicating an intestinal inflammatory response and disruption of barrier function. Many DEGs were mined by transcriptomic analysis, with tfrc, pfkp, egln1 enriched in the HlF-1 signaling pathway, hsp70, hsp90aa1 and hspa4 enriched in the Antigen processing and presentation pathway, pmm1, pfkfb3 and hk1 enriched in the Fructose and mannose metabolism patyway. The HIF-1 signaling pathway is a crucial regulatory pathway during acute heat stress in the G. eckloni intestine, while significant downregulation of genes associated with adaptive immunity (mica, hla-dpa1, hla-dpb1, and hla-dqb2) suggested impaired immune function. Additionally, the composition of the intestinal microbiota was dominated by Aeromonas, Citrobacter, and Acinetobacter in the control group; but there was a significant decrease in the abundance of Citrobacter and Acinetobacter, and a significantly increased in Shewanella and Hafnia-Obesumbacterium after acute heat stress. Correlation analyses revealed that changes in the abundance of Hafnia-Obesumbacterium, Buttiauxella, and Pseudomonas were closely associated with changes in gene expression associated with stress, inflammation, and immunity. These results comprehensively demonstrate the adaptive mechanisms of the G. eckloni intestine in response to acutely high temperatures and provide a theoretical basis for the future advancement of artificial culture of cold-water fish.

Body color is one of the most noticeable phenotypic and economic characteristics in fish. Fish exhibit a diverse array of body color mutations influenced by factors such as artificial selection and natural mutations. Elucidating the genetic mechanisms of these color variants in fish is crucial for developing new breeds with higher ornamental value. In this study, we identified a nonsense mutation in csf1ra (c. 1249 C>T) with whole genome resequencing technology, and which may potentially contribute to the albino phenotype in Channa asiatica. The albino individuals exhibited a substantial decrease in the expression level of csf1ra compared to that of the wild individuals. To unravel the underlying mechanism of csf1ra, we delved into comparative transcriptomic and gene expression analyses. Our findings suggest that csf1ra may impact tyrosine kinase activity. Furthermore, csf1ra may not only regulate the expression levels of genes (sox9, ephb6, and wnt9) involved in melanin-based pigmentation but also influence genes (ampd3, ak1, and bco1) associated with non-melanin-based pigmentation. Our study investigated the genetic basis of the albino mutant of C. asiatica and provided new insights into the function of csf1ra in fish pigmentation.

Global warming has heightened the severity and frequency of extreme high-temperature events, presenting challenges to fish survival and negatively affecting the production of fishery. Gymnocypris eckloni, native to the Tibetan Plateau, is widely cultured in southwest China. Its sensitivity to heat makes it a suitable model for studying the impact of high temperatures on fish. The heart is a vital organ for survival, while is relatively understudied concerning the impact of high temperatures on fish hearts. In this study, G. eckloni was subjected to a seven-day exposure to 27 °C followed by a transfer to 18 °C for a seven-day recovery period. Behavioral tests revealed a significant increase in locomotor speed, distance, and respiratory rate of G. eckloni at 27 °C. Serum indices exhibited significantly elevated stress indicators (cortisol) and kinases associated with heart damage (lactate dehydrogenase, lactate dehydrogenase isoenzyme 1, creatine kinase, creatine kinase isoenzyme, and aspartate transaminase) at 27 °C, and histological analyses have confirmed the occurrence of heart damage subjected to high temperatures. After 7 days of recovery, most of these indicators showed a significant decrease compared to the heat stress group, with no significant differences observed compared to the control group. Transcriptomic analyses have revealed the widespread involvement of ferroptosis, P53 signaling pathway, oxidative phosphorylation, myocardial contraction, and DNA repair pathway in the response of G. eckloni to high temperatures. Our study offers a systematic exploration of the effects of heat stress on G. eckloni, providing valuable insights for the cultivation of high-altitude fish.

To further investigate the influence of temperature and copper content on the carbon brush on the current-carrying friction of the carbon brush/friction disc contact pair. In this paper, the wear performance of five carbon brushes with different copper contents at two types of temperatures was discussed. The tests were carried out on a pin-disc type wear tester with a heating system. The results show there is a critical copper content that affects the friction performance of carbon brushes by influencing the integrity of the friction film. As the test temperature increases, the wear rate of the test samples in the high copper content group increases dramatically.

Ecological risk assessment (ERA) is an important element in territorial spatial planning, and the integration of ecosystem services into ERA is a current hot topic. In this study, taking the Tibetan Plateau as an example, a two-dimensional matrix is constructed based on the probability of risk occurrence and the possible loss caused by the risk for ecological risk assessment, with topographic sensitivity, ecological resilience, landscape vulnerability, and ecological sensitivity as probability representations, and the degradation of key ecosystem services as loss representations to improve the traditional ERA model. The results show that: (1) the probability shows a distribution pattern of high in the northwest and low in the southeast, with high-probability dominating, accounting for about 55.94%; the loss shows a distribution of low in the north and high in the south, with 30.54% of the region experiencing increased losses. (2) The ecological risk level is dominated by middle-high and high, the sum of the two accounts for 55.44%, while low and middle-low risk areas account for only 10.47%. Based on the proportion of high-risk in 45 cities, the risk control priority areas are identified: Naqu, Ali and Rikaze. (3) The Moran's I for probability, loss, and risk were 0.878, 0.615, and 0.567, respectively, indicating that all three showed significant positive spatial autocorrelation. The negative correlation between probability and loss indicates that there is spatial heterogeneity between them.

This paper applies the von Bertalanffy growth equation to study the age structure and growth characteristics of 210 Ptychobarbus dipogon collected in September 2019 in the middle and upper reaches of the Yarlung Zangbo River and employs FISAT II software to estimate the population characteristics’ parameters. Its aim is to provide a basis for the conservation of the population resources of the Ptychobarbus dipogon. In this study, the length of the catch ranged from 137 mm to 475 mm, the weight ranged from 44.04 g to 1142.80 g, the minimum age was 5 years, and the maximum age was 47 years. The body length–weight relationship was W(♀) = 4.1738 × 10−5L2.7687 (n = 86, R2 = 0.901); W(♂) = 2.7784 × 10−5L2.8434 (n = 100, R2 = 0.918). The growth equation was Lt(♀) = 505.000[1 − e−0.048(t−1.992)]; Lt(♂) = 452.254[1 − e−0.069(t−4.233)]; Wt(♀) = 1296.576[1 − e−0.048(t−1.992)]2.7687; Wt(♂) = 1001.872[1 − e−0.069(t−4.233)]2.8434. The inflection point ages of the female and male Ptychobarbus dipogon were 7.95 and 6.05, respectively. The exploitation rate of Ptychobarbus dipogon was 0.61, which exceeds the optimum exploitation rate of resources (0.57). The population resources are overfished. It is suggested to strengthen the conservation of Ptychobarbus dipogon population resources and the protection of native fish on the Qinghai–Tibet Plateau.

Galactooligosaccharides (GOS) are one of the most important functional oligosaccharide prebiotics. The surface display of enzymes was considered one of the most excellent strategies to obtain these products. However, a rough industrial environment would affect the biocatalytic process. The catalytic process could be efficiently improved using biofilm-based fermentation with high resistance and activity. Therefore, the combination of the surface display of β-galactosidase and biofilm formation in Pichia pastoris was constructed. The results showed that the catalytic conversion rate of GOS was up to 50.3% with the maximum enzyme activity of 5125 U/g by screening the anchorin, and the number of the continuous catalysis batches was up to 23 times. Thus, surface display based on biofilm-immobilized fermentation integrated catalysis and growth was a co-culture system, such that a dynamic equilibrium in the consolidated integrative process was achieved. This study provides the basis for developing biofilm-based surface display methods in P. pastoris during biochemical production processes.

The Lhasa River is one of the five tributaries of the Yarlung Zangbo River. It is the main industrial, agricultural and animal husbandry area in Tibet. It plays an important ecological security barrier role in regulating regional climate and maintaining biodiversity. In order to understand the resource utilization ability and relationship of fish in Lhasa River, and provide basic data for the protection and sustainable utilization of fish diversity in Lhasa River, the fishery resources in September 2019 (autumn), June 2020 (summer), November 2020 (winter) and March 2021 (spring) were investigated for the first time. The main fish in the catch were determined by the Index of Relative Importance (IRI). Shannon index and Pianka’s index were used to analyze the niche breadth and overlap values of the main fish caught in Lhasa River Basin from three dimensions of time, space and space–time. The results show that a total of 1399 fish of 3 orders and 4 families were collected. Among them, there is one dominant species, Schizopygopsis younghusbandi, and five common species, Schizothorax waltoni, Schizothorax oconnori, Ptychobarbus dipogon, Triplophysa stenura and Carassius auratus. The spatial–temporal niche breadth ranges from 1.395 to 3.628. They are Schizopygopsis younghusbandi, Carassius auratus, Ptychobarbus dipogon, Schizothorax oconnori, Triplophysa stenura and Schizothorax waltoni in a declining order. The temporal niche breadth is generally small, indicating that the survival activities of the main fish are greatly affected by seasonal changes. The fluctuation range of spatial–temporal overlap value is 0–0.535, and only 20% of the total logarithm is meaningful. The species pairs with temporal niche overlap values exceeding 0.300 reached 80%, while the spatial niche overlap value is generally low. The results show that the spatial and temporal distributions of the main fish in Lhasa River were quite different, and the spatial and temporal niche overlap value of the relationship between species is obviously affected by the change in spatial distribution. This demonstrates that the competition relationship and intensity of the main fish are quite different in different spatial positions.

Image super-resolution based on convolutional neural networks (CNN) is a hot topic in image processing. However, image super-resolution faces significant challenges in practical applications. Improving its performance on lightweight architectures is important for real-time super-resolution. In this paper, a joint algorithm consisting of modified particle swarm optimization (SMCPSO) and fast super-resolution convolutional neural networks (FSRCNN) is proposed. In addition, a mutation mechanism for particle swarm optimization (PSO) was obtained. Specifically, the SMCPSO algorithm was introduced to optimize the weights and bias of the CNNs, and the aggregation degree of the particles was adjusted adaptively by a mutation mechanism to ensure the global searching ability of the particles and the diversity of the population. The results showed that SMCPSO-FSRCNN achieved the most significant improvement, being about 4.84% better than the FSRCNN model, using the BSD100 data set at a scale factor of 2. In addition, a chest X-ray super-resolution images classification test experiment was conducted, and the experimental results demonstrated that the reconstruction ability of this model could improve the classification accuracy by 13.46%; in particular, the precision and recall rate of COVID-19 were improved by 45.3% and 6.92%, respectively.

Northern snakehead, Channa argus (C. argus), is an important economic and ecological fish species. The wild population of the species was sharply declined in the last decade. A high-quality reference genome could lay a solid foundation for the genetic and conservation studies for C. argus. In this work, we report a chromosomal genome assembly with PacBio and Hi-C technology using the albino northern snakehead, a color variety of C. argus. A 644.1-Mb genome with 24 chromosomes was obtained with a contig and scaffold N50 of 11.78 and 27.8 Mb, respectively. We inferred that C. argus diverged from A. testudineus around 85.6 million years ago. 514 expanded gene families and 214 positively selected genes were identified in the C. argus genome. The chromosome-level genome provides a valuable high-quality genomic resource for population, as well as genetic and evolutionary studies for C. argus and other species in Channidae.

There is an extremely complex interactive coupling relationship between social development and ecological protection, and how to achieve the coordinated development of the two is a hot topic in sustainable development research. This paper constructs a comprehensive evaluation index system of Social-Ecological System(SES) on the Qinghai-Tibet Plateau, and then multi-scale analysis of the coupling coordination status and temporal-spatial evolution characteristics of the SES from 2003 to 2018 based on the coupling coordination degree model(CCDM), scissors difference, etc.The results show that: (1) the comprehensive evaluation index of social system shows an increasing trend, with a growth rate of 16.46% and a spatial distribution pattern of high in the northeast and low in the southwest; the ecosystem comprehensive evaluation index fluctuates down, with a decline rate of 32.80% and a spatial distribution pattern of low in the northwest and high in the southeast. (2) There are differences in the types of coordination among different scales: the Qinghai-Tibet Plateau as a whole is mild disorders; on the provincial scale, the lowest coupling coordination degree is mild disorders in Tibet, followed by primary coordination in Sichuan and Qinghai, and Gansu, Yunnan, and Xinjiang are the highest, all of which are moderate coordination; on the county scale, the proportion of severe disorders, moderate disorders and primary coordination decreased by 7.03%, 2.63% and 7.20% respectively, while mild disorders and moderate coordination increased by 11.28% and 5.59% respectively. (3) The scissors difference rising in volatility, and the difference between the evolutionary trends of the two subsystems has increased. (4) The dynamic coupling degree is distributed in the interval of [45°, 90°], indicating that the SES of the Qinghai-Tibet Plateau is in a stage of common development, but the conflicts between the two are beginning to emerge. An in-depth analysis of the internal interaction process and the coupling coordination status of the SES can provide a theoretical basis and policy reference for sustainable development of the Qinghai-Tibet Plateau.