Network analysis reveals context-dependent structural complexity of social calls in serrate-legged small treefrogs.

Vocal communication plays an important role in survival, reproduction, and animal social association. Birds and mammals produce complex vocal sequence to convey context-dependent information. Vocalizations are conspicuous features of the behavior of most anuran species (frogs and toads), and males usually alter their calling strategies according to ecological context to improve the attractiveness/competitiveness. However, very few studies have focused on the variation of vocal sequence in anurans. In the present study, we used both conventional method and network analysis to investigate the context-dependent vocal repertoire, vocal sequence, and call network structure in serrate-legged small treefrogs Kurixalus odontotarsus. We found that male K. odontotarsus modified their vocal sequence by switching to different call types and increasing repertoire size in the presence of a competitive rival. Specifically, compared with before and after the playback of advertisement calls, males emitted fewer advertisement calls, but more aggressive calls, encounter calls, and compound calls during the playback period. Network analysis revealed that the mean degree, mean closeness, and mean betweenness of the call networks significantly decreased during the playback period, which resulted in lower connectivity. In addition, the increased proportion of one-way motifs and average path length also indicated that the connectivity of the call network decreased in competitive context. However, the vocal sequence of K. odontotarsus did not display a clear small-world network structure, regardless of context. Our study presents a paradigm to apply network analysis to vocal sequence in anurans and has important implications for understanding the evolution and function of sequence patterns.

A Machine learning model for predicting sepsis based on an optimized assay for microbial cell-free DNA sequencing.

OBJECTIVE: To integrate an enhanced molecular diagnostic technique to develop and validate a machine-learning model for diagnosing sepsis. METHODS: We prospectively enrolled patients suspected of sepsis from August 2021 to August 2023. Various feature selection algorithms and machine learning models were used to develop the model. The best classifier was selected using 5-fold cross validation set and then was applied to assess the performance of the model in the testing set. Additionally, we employed the Shapley Additive exPlanations (SHAP) method to illustrate the effects of the features. RESULTS: We established an optimized mNGS assay and proposed using the copies of microbe-specific cell-free DNA per milliliter of plasma (CPM) as the detection signal to evaluate the real burden, with strong precision and high accuracy. In total, 237 patients were eligible for participation, which were randomly assigned to either the training set (70 %, n = 165) or the testing set (30 %, n = 72). The random forest classifier achieved accuracy, AUC and F1 scores of 0.830, 0.918 and 0.856, respectively, outperforming other machine learning models in the training set. Our model demonstrated clinical interpretability and achieved good prediction performance in differentiating between bacterial sepsis and non-sepsis, with an AUC value of 0.85 and an average precision of 0.91 in the testing set. Based on the SHAP value, the top nine features of the model were PCT, CPM, CRP, ALB, SBPmin, RRmax, CREA, PLT and HRmax. CONCLUSION: We demonstrated the potential of machine-learning approaches for predicting bacterial sepsis based on optimized mcfDNA sequencing assay accurately.

Behavioral responses to predator and heterospecific alarm calls are habitat-specific in Eurasian tree sparrows.

Acoustic communication plays a vital role in predator-prey interactions. Although habitat structure has been shown to affect anti-predator tactics, little is known about how animals vary their behaviors in response to predator calls or heterospecific alarm calls in different environments. Here we used sound playbacks to test the responses of Eurasian tree sparrows (Passer montanus) foraging in harvested/unharvested rice paddy and open residential area. In the first experiment, we tested their behavioral responses to dove calls, male common cuckoo (Cuculus canorus) calls, hawk-like calls mimicked by female common cuckoo, sparrowhawk (Accipiter nisus) calls, and human yell calls produced to scare birds (predator signal playbacks). In the second experiment, we tested their behavioral responses to the Japanese tit's (Parus minor) territorial songs and alarm calls (heterospecific alarm signal playbacks). Results showed that the tree sparrows had less fleeing in unharvested ripe rice paddy than in harvested rice paddy and open residential area. In predator signal playbacks, call type affected the escape behavior of sparrows in unharvested rice paddy and open residential area but not harvested rice paddy. In alarm signal playbacks, tit alarm calls evoked more fleeing than territorial songs in harvested rice paddy and open residential area but not unharvested rice paddy. These results suggest that anthropogenic habitat changes may influence avian anti-predator tactics.

Genomic analysis reveals deep population divergence in the water snake Trimerodytes percarinatus (Serpentes, Natricidae).

Although several phylogeographic studies of Asian snakes have been conducted, most have focused on pitvipers, with non-venomous snakes, such as colubrids or natricids, remaining poorly studied. The Chinese keelback water snake (Trimerodytes percarinatus Boulenger) is a widespread, semiaquatic, non-venomous species occurring in China and southeastern Asia. Based on mitochondrial DNA (mtDNA) and single nucleotide polymorphism (SNP) data, we explored the population genetic structure, genetic diversity, and evolutionary history of this species. MtDNA-based phylogenetic analysis showed that T. percarinatus was composed of five highly supported and geographically structured lineages. SNP-based phylogenetic analysis, principal component analysis, and population structure analysis consistently revealed four distinct, geographically non-overlapping lineages, which was different from the mtDNA-based analysis in topology. Estimation of divergence dates and ancestral area of origin suggest that T. percarinatus originated ~12.68 million years ago (95% highest posterior density: 10.36-15.96 Mya) in a region covering southwestern China and Vietnam. Intraspecific divergence may have been triggered by the Qinghai-Xizang Plateau uplift. Population demographics and ecological niche modeling indicated that the effective population size fluctuated during 0.5 Mya and 0.002 Mya. Based on the data collected here, we also comment on the intraspecific taxonomy of T. percarinatus and question the validity of the subspecies T. p. suriki.

Collective effects of rising average temperatures and heat events on oviparous embryos.

Survival of the immobile embryo in response to rising temperature is important to determine a species' vulnerability to climate change. However, the collective effects of 2 key thermal characteristics associated with climate change (i.e., rising average temperature and acute heat events) on embryonic survival remain largely unexplored. We used empirical measurements and niche modeling to investigate how chronic and acute heat stress independently and collectively influence the embryonic survival of lizards across latitudes. We collected and bred lizards from 5 latitudes and incubated their eggs across a range of temperatures to quantify population-specific responses to chronic and acute heat stress. Using an embryonic development model parameterized with measured embryonic heat tolerances, we further identified a collective impact of embryonic chronic and acute heat tolerances on embryonic survival. We also incorporated embryonic chronic and acute heat tolerance in hybrid species distribution models to determine species' range shifts under climate change. Embryos' tolerance of chronic heat (T-chronic) remained consistent across latitudes, whereas their tolerance of acute heat (T-acute) was higher at high latitudes than at low latitudes. Tolerance of acute heat exerted a more pronounced influence than tolerance of chronic heat. In species distribution models, climate change led to the most significant habitat loss for each population and species in its low-latitude distribution. Consequently, habitat for populations across all latitudes will shift toward high latitudes. Our study also highlights the importance of considering embryonic survival under chronic and acute heat stresses to predict species' vulnerability to climate change.

Efectos colectivos del aumento de las temperaturas promedio y los eventos de calor en embriones ovíparos Resumen La supervivencia de los embriones inmóviles en respuesta al incremento de temperatura es importante para determinar la vulnerabilidad de las especies al cambio climático. Sin embargo, los efectos colectivos de dos características térmicas claves asociadas con el cambio climático (i. e., aumento de temperatura promedio y eventos de calor agudo) sobre la supervivencia embrionaria permanecen en gran parte inexplorados. Utilizamos mediciones empíricas y modelos de nicho para investigar cómo el estrés térmico crónico y agudo influye de forma independiente y colectiva en la supervivencia embrionaria de los lagartos en todas las latitudes. Recolectamos y criamos lagartos de cinco latitudes e incubamos sus huevos en un rango de temperaturas para cuantificar las respuestas específicas de la población al estrés por calor crónico y agudo. Posteriormente, mediante un modelo de desarrollo embrionario parametrizado con mediciones de tolerancia embrionaria al calor, identificamos un impacto colectivo de las tolerancias embrionarias al calor agudo y crónico en la supervivencia embrionaria. También incorporamos la tolerancia embrionaria crónica y aguda al calor en modelos de distribución de especies híbridas para determinar los cambios de distribución de las especies bajo el cambio climático. La tolerancia embrionaria al calor crónico (T­crónico) permaneció constante, mientras que la tolerancia al calor agudo (T­agudo) fue mayor en latitudes altas que en latitudes bajas. La tolerancia al calor agudo ejerció una influencia más pronunciada que la tolerancia al calor crónico. En los modelos de distribución de especies, el cambio climático provocó la pérdida de hábitat más significativa para cada población y especie en su distribución de latitudes bajas. En consecuencia, el hábitat para poblaciones en todas las latitudes se desplazará a latitudes altas. Nuestro estudio también resalta la importancia de considerar la supervivencia embrionaria bajo estrés térmico crónico y agudo para predecir la vulnerabilidad de las especies al cambio climático.

Auditory sensitivity and tympanic middle ear in a vocal and a non-vocal frog.

The tympanic middle ear is important for anuran hearing on land. However, many species have partly or entirely lost their tympanic apparatus. Previous studies have compared hearing sensitivities in species that possess and lack tympanic membranes capable of sound production and acoustic communication. However, little is known about how these hearing abilities are comparable to those of mutant species. Here, we compared the eardrum and middle ear anatomies of two sympatric sibling species from a noisy stream habitat, namely the "non-vocal" Hainan torrent frog (Amolops hainanensis) and the "vocal" little torrent frog (Amolops torrentis), the latter of which is capable of acoustic communication. Our results showed that the relative (to head size) eardrum diameter of A. hainanensis was smaller than that of A. torrentis, although the absolute size was not smaller. Unlike A. torrentis, the tympanic membrane area of A. hainanensis was not clearly differentiated from the surrounding skin. The middle ear, however, was well-developed in both species. We measured the auditory brainstem responses (ABRs) of A. hainanensis and compared the ABR thresholds and latencies to those previously obtained for A. torrentis. Our results suggested that these two species exhibited significant differences in hearing sensitivity. A. hainanensis (smaller relative eardrum, nonvocal) had higher ABR thresholds and longer initial response times than A. torrentis (larger relative eardrum, vocal) at lower frequencies. Neurophysiological responses from the brain were obtained for tone pips between 800 Hz and 7,000 Hz, with peak sensitivities found at 3,000 Hz (73 dB SPL) for A. hainanensis, and at 1,800 Hz (61 dB SPL) for A. torrentis. Our results suggest that the non-vocal A. hainanensis has lower hearing sensitivity than its vocal sister species (i.e., A. torrentis), which may be related to differences in tympanic or inner ear structure and morphology.

Microplastic Distribution Characteristics and Sources on Beaches That Serve as the Largest Nesting Ground for Green Turtles in China.

The threat of microplastics to marine animals and habitats is increasing, which may affect sea turtle nesting grounds. The Qilianyu Islands are the largest remaining green turtle (Chelonia mydas) nesting grounds in China. Despite being far from the mainland, microplastic pollution cannot be ignored. In this study, the level of microplastic pollution in surface sediments from three different zones, namely, the bottom, intertidal, and supratidal zone, was investigated on North Island, Qilianyu Islands. The results showed that the abundance of microplastics in the supratidal zone was significantly higher than that in the bottom zone and intertidal zone (r = 3.65, p = 0.011), with the highest average abundance of microplastics located on the southwest coast of North Island. In the bottom zone, only plastic blocks (88%) and fibers (12%) were found. The main types of microplastics in the intertidal and supratidal zones were plastic blocks (48%) and foam (42%), with polyethylene (PE) (40%) and polystyrene (PS) (34%) being the predominant components. These types and components of microplastics differed from those in the surrounding seawater, but corresponding types and components were found in the plastic debris on the beach. Meanwhile, it was also observed that there were multiple instances of fragmented plastic on the beach. Thus, we suggest that the microplastics on the beach in North Island were mainly derived from the fragmentation of microplastic debris, indicating secondary microplastics. It is recommended to further strengthen the regular cleaning of plastic debris on the beach, especially the removal of small plastic debris, in order to reduce the pollution from secondary microplastics generated by the fragmentation of beach plastic debris and to better protect China's most important sea turtle nesting site in the South China Sea.

Phenolic compounds induce ferroptosis-like death by promoting hydroxyl radical generation in the Fenton reaction.

Phenolic compounds are industrially versatile chemicals, also the most ubiquitous pollutants. Recently, biosynthesis and biodegradation of phenols has attracted increasing attention, while phenols' toxicity is a major issue. Here, we evolved phloroglucinol-tolerant Escherichia coli strains via adaptive evolution, and three mutations (ΔsodB, ΔclpX and fetAB overexpression) prove of great assistance in the tolerance improvement. We discover that phloroglucinol complexes with iron and promotes the generation of hydroxyl radicals in Fenton reaction, which leads to reducing power depletion, lipid peroxidation, and ferroptosis-like cell death of E. coli. Besides phloroglucinol, various phenols can trigger ferroptosis-like death in diverse organisms, from bacteria to mammalian cells. Furthermore, repressing this ferroptosis-like death improves phloroglucinol production and phenol degradation by corresponding strains respectively, showing great application potential in microbial degradation or production of desired phenolic compounds, and phloroglucinol-induced ferroptosis suppresses tumor growth in mice, indicating phloroglucinol as a promising drug for cancer treatment.

A novel index for vegetation drought assessment based on plant water metabolism and balance under vegetation restoration on the Loess Plateau.

Vegetation is vital to the ecosystem, contributing to the global carbon balance, but susceptible to the impacts of climate change. Monitoring vegetation drought remains challenging due to the lack of widely accepted drought indices. This study focused on vegetation, and simulated the vegetation suitable water demand and soil available water supply (calculated by Remote-sensing-based Water Balance Assessment Tool model). The standardized Vegetation Water deficit Index (SVWDI) was established by calculating the vegetation water deficit, which reflects the response of vegetation to drought. We examined the spatiotemporal evolution of vegetation drought on the Loess Plateau and evaluated the applicability of standardized vegetation water deficit index. Our findings revealed that the standardized vegetation water deficit index demonstrated an overall upward trend across different time scales from 1991 to 2020. Drought conditions were concentrated in the first 20 years of the study period, but vegetation drought on the Loess Plateau has been alleviated in the past decade. Moreover, as the time scale extended, the trend of SVWDI generally decreased, with approximately 49.50 % (1-month scale), 46.66 % (3-month scale), 47.08 % (12-month scale), and 32.16 % (24-month scale) of the grid areas experiencing increased SVWDI. The correlation between SVWDI and tree-ring width index (TRWI) performed well under all precipitation gradients, but the Palmer drought severity index (PDSI) was only highly correlated with TRWI in regions with low precipitation. In terms of the relationship with vegetation health, SVWDI demonstrated the highest correlation with the normalized difference vegetation index (NDVI) across different time scales, followed by PDSI and standardized precipitation evapotranspiration index (SPEI). This study provides insights into the evolution of vegetation drought in response to climate change. The findings can guide initiatives such as returning farmland to forest and grassland on the Loess Plateau to aid climate change adaptation strategies.

Antifertility effects of EP-1 (quinestrol and levonorgestrel) on Pacific rats (Rattus exulans).

Pest rodents pose a serious threat to island biodiversity. Fertility control could be an alternative approach to control the impact of rodents on these islands. In this study, we examined the antifertility effects of EP-1 baits containing quinestrol (E) and levonorgestrel (P) using a dose of 50 ppm E and P at three different ratios (E:P ratio = 1:2, 1:1, and 2:1) on Pacific rats (Rattus exulans) in the Xisha Islands, Hainan, China. Compared to the control group, all animals in EP-1 treatment groups showed significantly decreased food intake and body weight. In treated males, there were obvious abnormalities in testis structure and a significant decrease of relative seminal vesicle weight, but no significant effect on relative uterine and ovarian weights (g kg-1 body weight), or ovarian structure in females. Adding 8% sucrose to the original 50-ppm baits (E:P ratio = 1:1) significantly increased bait palatability for males and females. This dose induced uterine edema and abnormalities of ovarian structure in females but had no significant negative effect on the relative testis, epididymis, and seminal vesicle weights (g kg-1 body weight) or sperm density in males. In summary, 50-ppm EP-1 (1:1) baits have the potential to disrupt the fertility of females, and 8% sucrose addition to the EP-1 baits (E:P ratio = 1:1) could improve bait palatability. This dose disrupted the testis structure in males. Future studies are needed to improve bait acceptance and assess the antifertility effects of EP-1 (1:1) on Pacific rats in captive breeding trials and under field conditions.

The Characterization of Mitochondrial Genome of Spotted Pond Turtle (Geoclemys hamiltonii).

The spotted pond turtle Geoclemys hamiltonii (Gray, 1830) is widely distributed in the Indus, Ganges, and Brahmaputra river basins. In this study, the complete mitochondrial genome (mitogenome) of G. hamiltonii was sequenced using the next-generation sequencing (NGS) and Sanger sequencing, and the essential characteristics, gene arrangement, and phylogenetic relationship were analyzed. The results showed that the G. hamiltonii mitogenome was 16,505 bp in length (A: 33.6%, C: 27.1%, G: 13.4%, T: 25.8%) and consisted of 22 tRNAs, 13 protein-coding genes, two ribosomal RNA genes, and a non-coding control region (GenBank accession ON243873). The genome composition of G. hamiltonii presented a slight A + T bias (59.4%), and showed a positive AT skew (0.131) and a negative GC skew (- 0.338). All tRNAs had the typical clover structure, except trnS1 (GCT). The gene order of the G. hamiltonii mitogenome was the same as other Geoemydidae mitogenomes. A phylogenetic analysis based on the complete mitogenome indicated that the G. hamiltonii grouped independently of other species in the family Geoemydidae, supporting the species' placement in the monotypic genus Geoclemys. Our results describe a novel genome at the species level. As the first complete mitogenome of G. hamiltonii, it provided valuable molecular information for phylogenetic and conservation genetics analyses of G. hamiltonii.

Prevalence and association of early onset severe hyperbilirubinemia in newborn in the East China region: Retrospective medical record analyses.

Research on the prevalence and association of hyperbilirubinemia is controversial because of different cultures, demographics, and clinical conditions. The etiology of hyperbilirubinemia is affected by the environment and other factors in the newborn. The World Health Organization recommended a 1-day hospital stay after uncomplicated delivery, jaundice assessment before discharge, and screening on 3rd and 7th days after birth for hyperbilirubinemia. However, the implementation of these recommendations is difficult in China. The objective of this study was to evaluate the prevalence and association of early onset severe hyperbilirubinemia in newborns in East China. Retrospective medical record analyses for 250 cesarean sections or vaginal deliveries, ≥2 kg body weight, and negative for Hepatitis B surface antigen by birth newborns were performed. A biochemical analyzer, quantitative assay, and quantitative polymerase chain reaction were used to evaluate total serum bilirubin, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and gene variant phenotyping, respectively. A total in 33 (13%) newborns were reported with early onset severe hyperbilirubinemia (according to the American Academy of Pediatrics, total serum bilirubin ≥ 342 µmol/L within 6 hours of birth). All newborns with severe hyperbilirubinemia were hospitalized and underwent phototherapy. The mothers of all newborns had a gestational age ≥ 35 weeks. Hospitalization included artificial feeding, and breastfeeding was rare (P < .0001). ABO incompatibility ("O" blood type for mother and either "A" or "AB" or "B" blood type for newborn, P = .0411), G6PD deficiency (G6PD/6-phosphogluconate dehydrogenase ≤ 1.0 in quantitative assay, P = .0422), Rh incompatibility (the mother's blood type was Rh negative and newborn blood type was Rh positive, P = .0416), fewer genotype rs4149056 frequencies (P = .0452), higher genotype rs2306283 frequencies (P = .0461), and higher genotype rs1805173 frequencies (P = .0471) were independent parameter for early onset severe hyperbilirubinemia of newborns. The prevalence of early onset severe hyperbilirubinemia in Chinese newborns is 13% in the East China region. Blood incompatibility, G6PD deficiency, fewer genotype rs4149056 frequencies, higher genotype rs2306283 frequencies, and higher genotype rs1805173 frequencies were independent predictors of early onset severe hyperbilirubinemia among newborns in the East China region (Level of Evidence: IV; Technical Efficacy: Stage 5).

Microhabitat characteristics of the critically endangered big-headed turtle Platysternon megacephalum.

Understanding the microhabitat requirements of an animal is vital for ensuring the success of targeted conservation and microhabitat restoration measures. The big-headed turtle (Platysternon megacephalum) is a freshwater species that is distributed across Southeast Asia. Owing to the human threats posed by illegal pet trade and overharvesting for food and medicinal purposes, the species has undergone rapid decline. However, in Hainan, their microhabitat characteristics are still unknown, which is neither conducive to the conservation of the species nor to the establishment of the Hainan Tropical Rainforest National Park. This study examined the microhabitat characteristics of P. megacephalum using sample plot methods in the Diaoluo Mountain area of Hainan Tropical Rainforest National Park. Our results indicated that P. megacephalum prefers stream microhabitats with rocky substrates, several caves, and a high diversity of food sources. Microhabitat characteristics did not differ significantly between adults and juveniles. Our results suggest that protecting microhabitats and main food sources is important for the conservation of P. megacephalum. Our findings provide a reference for the protection of this species in Jianfeng Ridge, Yingge Ridge, and other areas in Hainan Tropical Rainforest National Park.

Effects of Barefoot and Shod Conditions on the Kinematics and Kinetics of the Lower Extremities in Alternating Jump Rope Skipping-A One-Dimensional Statistical Parameter Mapping Study.

PURPOSE: To explore the difference in the biomechanics of the lower extremity during alternating jump rope skipping (AJRS) under barefoot and shod conditions. METHODS: Fourteen experienced AJRS participants were randomly assigned to wear jump rope shoes or be barefoot (BF) during the AJRS at a self-selected speed. The Qualisys motion capture system and Kistler force platform were used to synchronously collect the ground reaction forces and trajectory data of the hip, knee, ankle, and metatarsophalangeal (MTP) joints. One-dimensional statistical parameter mapping was used to analyze the kinematics and kinetics of the lower extremity under both conditions using paired t-tests. RESULTS: Wearing shoes resulted in a significant decrease in the ROM (p < 0.001) and peak angular velocity (p < 0.001) of the MTP joint during the landing phase. In addition, the MTP joint power (p < 0.001) was significantly larger under shod condition at 92-100% of the landing phase. Moreover, wearing shoes reduced the peak loading rate (p = 0.002). CONCLUSION: The findings suggest that wearing shoes during AJRS could provide better propulsion during push-off by increasing the MTP plantarflexion joint power. In addition, our results emphasize the significance of the ankle and MTP joint by controlling the ankle and MTP joint angle.

Corrigendum: Improved single-cell genome amplification by a high-efficiency phi29 DNA polymerase.

[This corrects the article DOI: 10.3389/fbioe.2023.1233856.].

Improved single-cell genome amplification by a high-efficiency phi29 DNA polymerase.

Single-cell genomic whole genome amplification (WGA) is a crucial step in single-cell sequencing, yet its low amplification efficiency, incomplete and uneven genome amplification still hinder the throughput and efficiency of single-cell sequencing workflows. Here we introduce a process called Improved Single-cell Genome Amplification (iSGA), in which the whole single-cell sequencing cycle is completed in a high-efficient and high-coverage manner, through phi29 DNA polymerase engineering and process engineering. By establishing a disulfide bond of F137C-A377C, the amplification ability of the enzyme was improved to that of single-cell. By further protein engineering and process engineering, a supreme enzyme named HotJa Phi29 DNA Polymerase was developed and showed significantly better coverage (99.75%) at a higher temperature (40°C). High single-cell genome amplification ability and high coverage (93.59%) were also achieved for commercial probiotic samples. iSGA is more efficient and robust than the wild-type phi29 DNA polymerase, and it is 2.03-fold more efficient and 10.89-fold cheaper than the commercial Thermo Scientific EquiPhi29 DNA Polymerase. These advantages promise its broad applications in large-scale single-cell sequencing.

Keep numbers in view: red-eared sliders (Trachemys scripta elegans) learn to discriminate relative quantities.

The ability to discriminate relative quantities, one of the numerical competences, is considered an adaptive trait in uncertain environments. Besides humans, previous studies have reported this capacity in several non-human primates and birds. Here, we test whether red-eared sliders (Trachemys scripta elegans) can discriminate different relative quantities. Subjects were first trained to distinguish different stimuli with food reward. Then, they were tested with novel stimulus pairs to demonstrate how they distinguished the stimuli. The results show that most subjects can complete the initial training and use relative quantity rather than absolute quantity to make choices during the testing phase. This study provides behavioural evidence of relative quantity discrimination in a reptile species and suggests that such capacity may be widespread among vertebrates.

Single-cell transcriptomic landscape of peripheral blood cells provides insights into adaptation of red-eared sliders (Trachemys scripta elegans).

Red-eared sliders (Trachemys scripta elegans), as one of the 100 most threatening aliens, have stronger immunity than the native species in response to environmental stress. Blood cells are an important component of immunity in the body. However, the blood cell researches of turtle are still in the traditional blood cell classification and morphological structure observation. Furthermore, turtle granulocytes cannot be accurately identified using traditional methods. Single-cell RNA sequencing techniques have been successfully implemented to study cells based on the mRNA expression patterns of each cell. The present study profiled the transcriptomes of peripheral blood cells in red-eared sliders to construct a single-cell transcriptional landscape of the different cell types and explored environmental adaptation mechanism from the perspective of hematology. All 14 transcriptionally distinct clusters (platelets, erythrocytes1, erythrocytes2, CSF1R monocytes, POF1B monocytes, neutrophils, GATA2high basophils, GATA2low basophils, CD4 T cells, CD7 T cells, B cells, ACKR4 cells, serotriflin cells, and ficolin cells) were identified in the peripheral blood cells of the red-eared sliders. In particular, a subtype of erythrocytes (erythrocytes1) that expressed immune signals was identified. Peripheral blood cells were grouped into three lineages: platelet, erythroid/lymphoid, and myeloid cell lineages. Furthermore, based on differentiation trajectory and up-regulated gene expression, ACKR4 cells were newly identified as lymphocytes, and serotriflin and ficolin cells as granulocytes. The single-cell transcriptional atlas of the peripheral blood cells in red-eared sliders provided in the present study will offer a comprehensive transcriptome reference for the exploration of physiological and pathological hematology in this species.

Progress and opportunities for metal-organic framework composites in electrochemical sensors.

Metal-organic framework composites have the advantages of large surface area, high porosity, strong catalytic efficiency and good stability, which provide a great possibility of finding excellent electrode materials for electrochemical sensors. However, MOF composites still face various challenges and difficulties, which limit their development and application. This paper reviews the application of MOF composites in electrochemical sensors, including MOF/carbon composites, MOF/metal nanoparticle composites, MOF/metal oxide composites and MOF/enzyme composites. In addition, the application challenges of MOF composites in electrochemical sensors are summarized. Finally, the application prospect for MOF composites is considered to promote the synthesis of more MOF composites with excellent properties.

Diversity of Underwater Vocalizations in Chinese Soft-Shelled Turtle (Pelodiscus sinensis).

Sound communication is important for underwater species. The wild population of the Chinese soft-shelled turtle (Pelodiscus sinensis) is listed as vulnerable. However, its vocalization, which can serve as the basis for ecological and evolutionary research, has not been studied. Here, we performed underwater recordings of 23 Chinese soft-shelled turtles of different ages and sexes and identified 720 underwater calls. The turtle calls were manually divided into 10 call types according to visual and aural inspection properties. The similarity test indicated that the manual division was reliable. We described the acoustic properties of the calls and the statistical analysis showed that the peak frequency of calls was significantly different between adult females and males, and also between subadults and adults. Similar to other aquatic turtles that prefer to live in deep water, Chinese soft-shelled turtles have a high vocal diversity and many harmonic calls, indicating that this highly aquatic species developed a variety of vocalizations to enhance their underwater communication, which helped them adapt to the complex and dim underwater environment. Furthermore, the turtles showed a tendency for vocalization to become more diverse with age.