High-throughput sequencing and characterization of potentially pathogenic fungi from the vaginal mycobiome of giant panda (Ailuropoda melanoleuca) in estrus and non-estrus

IntroductionThe giant panda (Ailuropoda melanoleuca) reproduction is of worldwide attention, and the vaginal microbiome is one of the most important factors affecting the reproductive rate of giant pandas. The aim of this study is to investigate the diversity of vaginal mycobiota structure, and potential pathogenic fungi in female giant pandas during estrus and non-estrus.MethodsThis study combined with high-throughput sequencing and laboratory testing to compare the diversity of the vaginal mycobiota in giant pandas during estrus and non-estrus, and to investigate the presence of potentially pathogenic fungi. Potentially pathogenic fungi were studied in mice to explore their pathogenicity.Results and discussionThe results revealed that during estrus, the vaginal secretions of giant pandas play a crucial role in fungal colonization. Moreover, the diversity of the vaginal mycobiota is reduced and specificity is enhanced. The abundance of Trichosporon and Cutaneotrichosporon in the vaginal mycobiota of giant pandas during estrus was significantly higher than that during non-estrus periods. Apiotrichum and Cutaneotrichosporon were considered the most important genera, and they primarily originate from the environment owing to marking behavior exhibited during the estrous period of giant pandas. Trichosporon is considered a resident mycobiota of the vagina and is an important pathogen that causes infection when immune system is suppressed. Potentially pathogenic fungi were further isolated and identified from the vaginal secretions of giant pandas during estrus, and seven strains of Apiotrichum (A. brassicae), one strain of Cutaneotrichosporon (C. moniliiforme), and nine strains of Trichosporon (two strains of T. asteroides, one strain of T. inkin, one strain of T. insectorum, and five strains of T. japonicum) were identified. Pathogenicity results showed that T. asteroides was the most pathogenic strain, as it is associated with extensive connective tissue replacement and inflammatory cell infiltration in both liver and kidney tissues. The results of this study improve our understanding of the diversity of the vaginal fungi present in giant pandas and will significantly contribute to improving the reproductive health of giant pandas in the future

First Report of a Novel Hepatozoon sp. in Giant Pandas (Ailuropoda melanoleuca)

The first report of giant pandas (Ailuropoda melanoleuca) infected with a novel Hepatozoon species is presented. An intraleukocytic parasite was detected via routine blood smear from a zoo-housed giant panda at the National Zoological Park. Ribosomal DNA sequences indicated a previously undescribed Hepatozoon species. Phylogenetic and distance analyses of the sequences placed it within its own branch, clustered with Old World species with carnivore (primarily ursid and mustelid) hosts. Retrospective and opportunistic testing of other individuals produced additional positive detections (17/23, 73.9%), demonstrating 100% prevalence (14/14) across five institutions. All animals were asymptomatic at time of sampling, and health implications for giant pandas remain unknown

Statistical Model of College Ideological and Political Learning Based on Fractional Differential Equations

Based on fractional differential equations, this paper focuses on the internal mechanism of college ideological and political learning. We also elaborate on its microstructure, channel characteristics, and competitive field. We put forward Gauss’s theorem and the loop theorem of the related field of ideological and political learning in colleges and universities. At the same time, the convexity theorem of the information entropy of the competitive field and the principle of maximum entropy are proved. Research shows that college students can change the relationship between student learning and society by adapting, functioning, and coordinating. We need to help students develop more effective political learning strategies

Fe–N–C single-atom catalysts with an axial structure prepared by a new design and synthesis method for ORR

Fe–N–C single-atom catalysts usually exhibit poor ORR activity due to their unsatisfactory O2 adsorption and activation. Here, a new design idea and tailored self-assembly synthesis method are reported to improve their ORR performance. DFT calculations indicate that the ORR electrocatalytic activity of Fe–N–C single-atom catalysts with an axial structure is superior to that of Fe–N–C single-atom catalysts with a Fe–N4 active site. In order to experimentally demonstrate the difference, Fe–N–C single-atom catalysts with a Fe–N5 active site were successfully synthesized on the surface of monolayer graphene. XANES, SEM, HRTEM, XRD, Raman and XPS analyses indicate that the synthesized Fe–N–C catalyst possessed nanofibre morphology and a curved layer-like crystal structure. For comparison, FePc powder was used as the FePc(Fe–N4) catalyst as its molecular structure involves a Fe–N4 active site embedded in carbon six-membered rings. The current density of the synthesized Fe–N5/C@G catalyst at a potential of 0.88 V vs. RHE is 1.65 mA cm−2, which is much higher than that of the FePc(Fe–N4) catalyst (1.04 mA cm−2) and even higher than that of commercial Pt/C catalyst (1.54 mA cm−2). The results are very well consistent with the DFT calculations, verifying the dependability and accuracy of DFT calculations. This work reports a new synthetic idea to obtain better performance and proposes a formation mechanism to explain the process of the synthesis method

Study on the Influence of PCA Pre-Treatment on Pig Face Identification with Random Forest

To explore the application of a traditional machine learning model in the intelligent management of pigs, in this paper, the influence of PCA pre-treatment on pig face identification with RF is studied. By this testing method, the parameters of two testing schemes, one adopting RF alone and the other adopting RF + PCA, were determined to be 65 and 70, respectively. With individual identification tests carried out on 10 pigs, accuracy, recall, and f1-score were increased by 2.66, 2.76, and 2.81 percentage points, respectively. Except for the slight increase in training time, the test time was reduced to 75% of the old scheme, and the efficiency of the optimized scheme was greatly improved. It indicates that PCA pre-treatment positively improved the efficiency of individual pig identification with RF. Furthermore, it provides experimental support for the mobile terminals and the embedded application of RF classifiers

Role of natural resources, renewable energy sources, eco-innovation and carbon taxes in carbon neutrality: Evidence from G7 economies

Global warming has created problems for human life, and it has been increasing for a few years. All the developing and developed countries are establishing policies to attain zero carbon status. This study extends the ongoing debate on carbon emissions. It examines the effect of natural resources and RE (Biofuel and other renewable sources) on greenhouse gas (CO2 emission and PM2.5) emissions while using data over 22 years (1999–2021) from G7 countries. In addition, this study has investigated the effect of carbon taxes, financial development, and environmental policies on carbon neutrality. The cross-sectional-ARDL, the Common correlated effect means group (CCEMG), and the Augmented mean group (AMG) cutting-edge model have been employed. Quantile regression has been employed for robustness. The study results demonstrate that biofuel and other renewable energy (RE) sources, carbon taxes, environmental policy, and eco-innovation decrease greenhouse gas emissions (CO2 emissions). Meanwhile, financial development, and natural resource dependence positively impact carbon neutrality. The robustness result also verifies the findings from CS-ARDL, AMG, and CCEMG methods. The empirical findings are used to infer policy implications for G7 economies

Surveillance Study of Klebsiella pneumoniae in the Giant Panda Revealed High Genetic Diversity and Antibiotic Therapy Challenge

Klebsiella pneumoniae is not only a worldwide human pathogen, it also effects wildlife, such as the giant panda (Ailuropoda melanoleuca), in which it has recently been evidenced to result in diarrhea, organ failure, and even death. A K. pneumoniae investigation was carried out at the Chengdu Research Base of Giant Panda Breeding in 2018. As part of the investigation, the pulsed-field gel electrophoresis (PFGE) typing, multilocus-sequence typing (MLST), antibiotic resistance profiles (ARPs), and antibiotic resistance genes (ARGs) were studied based on all isolates. Fecal samples were collected from 72 A. melanoleuca from May to December 2018, and a total of 90 K. pneumoniae were isolated from 153 fecal samples. The genotyping results showed that the isolates had high diversity, of which 84 clusters were obtained by PFGE and 57 STs by MLST. The overall trend of the similarity of isolates was the first sample period > second sample period > third sample period, which showed the increasement of genome variability of K. pneumoniae. In addition, 90 isolates showed high resistance to ampicillin, rifampicin, and compound sulfamethoxazole. Of the obtained isolates, 50% carried 6~8 ARPs, and the carrying volume increased during three sample periods, in which we found two isolates carrying 12 and 13 ARPs during the third sample period, respectively. Moreover, a total of 65 ARGs were detected (90.28%, 65/72) in 90 K. pneumoniae samples. Almost all bacteria sampled contained 17 ARGs that belonged to the β-lactamase, Multidrug, MGEs, Aminoglycoside, and Tetracycline, which may be the basis of ARPs of K. pneumoniae. Moreover, the types of Multidrug and MGEs had a greater impact on antibiotic susceptivity of K. pneumoniae. Our results showed that K. pneumoniae has a serious risk of transmission in A. melanoleuca and K. pneumoniae had a high possibility of genome diversity and the risk of drugs tolerance under the large antibiotic usage

Structural Analyses of a Dominant Cryptosporidium parvum Epitope Presented by H-2Kb Offer New Options To Combat Cryptosporidiosis

ABSTRACT Cryptosporidium parvum has gained much attention as a major cause of diarrhea in the world, particularly in those with compromised immune systems. The data currently available on how the immune system recognizes C. parvum are growing rapidly, but we lack data on the interactions among host major histocompatibility complex (MHC) diversity and parasitic T-cell epitopes. To identify antigenic epitopes in a murine model, we performed systematic profiling of H-2Kb-restricted peptides by screening the dominant Cryptosporidium antigens. The results revealed that the glycoprotein-derived epitope Gp40/15-SVF9 induced an immunodominant response in C. parvum-recovered C57BL/6 mice, and injection of the cytotoxic-T-lymphocyte (CTL) peptide with the adjuvant activated peptide-specific CD8+ T cells. Notably, the SVF9 epitope was highly conserved across Cryptosporidium hominis, C. parvum, and many other Cryptosporidium species. SVF9 also formed stable peptide-MHC class I (MHC I) complexes with HLA-A*0201, suggesting cross-reactivity between H-2Kb and human MHC I specificities. Crystal structure analyses revealed that the interactions of peptide-MHC surface residues of H-2Kb and HLA-A*0201 are highly conserved. The hydrogen bonds of H-2Kb–SVF9 are similar to those of a dominant epitope presented by HLA-A*0201, which can be recognized by a public human T-cell receptor (TCR). Notably, we found double conformations in position 4 (P4), 5 (P5) of the SVF9 peptide, which showed high flexibility, and multiple peptide conformations generated more molecular surfaces that can potentially be recognized by TCRs. Our findings demonstrate that an immunodominant C. parvum epitope and its homologs from different Cryptosporidium species and subtypes can benefit vaccine development to combat cryptosporidiosis. IMPORTANCE Adaptive immune responses and T lymphocytes have been implicated as important mechanisms of parasite-induced protection. However, the role of CD8+ T lymphocytes in the resolution of C. parvum infection is largely unresolved. Our results revealed that the glycoprotein-derived epitope Gp40/15-SVF9 induced an immunodominant CD8+ T-cell response in C57BL/6 mice. Crystal structure analyses revealed that the interactions of the H-2Kb–SVF9 peptide are similar to those of a dominant epitope presented by HLA-A*0201, which can be recognized by human TCRs. In addition, we found double conformations of the SVF9 peptide, which showed high flexibility and multiple peptide conformations that can potentially be recognized by TCRs

Comparison of a commercial ELISA and indirect hemagglutination assay with the modified agglutination test for detection of Toxoplasma gondii antibodies in giant panda (Ailuropoda melanoleuca)

Toxoplasma gondii is a worldwide-distributed zoonotic protozoan parasite which causes toxoplasmosis and has a significant effect on public health. In the giant panda (Ailuropoda melanoleuca), toxoplasmosis can cause asymptomatic infections, reproductive disorder and even death, which poses a serious threat to the conservation of this rare protected species. Therefore, serological investigation of T. gondii is essential to understanding its risk to giant pandas, however, there are no specific testing kits for giant pandas. Previous research has used MAT as the reference method for screening T. gondii, to investigate this further, this study focused on the agreement comparing of MAT with ELISA and IHA tests for detecting T. gondii antibodies in 100 blood samples from 55 captive giant pandas in Chengdu, China. The results showed 87.0%, 87.0%, 84.0%, samples were sero-positive for T. gondii using ELISA (kits a, b, c), respectively, while MAT and IHA tests were 84.0% and 9.0% sero-positive, respectively. There was no significant difference between MAT and the three ELISA kits and these two methods had substantial agreement (0.61 < қ ≤ 0.80). Meanwhile, there was a significant difference (P < 0.001) between MAT and IHA, and these two methods had only a slight agreement (қ ≤ 0.20). The relative sensitivity of the ELISA (kits a, b, c) were 89.0%, 91.5% and 95.1%, and the specificity were 86.7%, 80.0% and 80.0%, respectively, which showed these three ELISA kits all had great accuracy. It is suggested that MAT is the recommended test method for primary screening T. gondii in giant pandas and then verified by ELISA