13 research outputs found

    Pseudogenization of Mc1r gene associated with transcriptional changes related to melanogensis explains leucistic phenotypes in Oreonectes cavefish (Cypriniformes, Nemacheilidae)

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    Organisms that have colonized underground caves encounter vastly different selective pressures than their relatives in above‐ground habitats. While disruption of certain pigmentation genes has been documented in various cave‐dwelling taxa, little is known about wider impacts across pigmentation and other gene pathways. We here study the timeframe and transcriptional landscape of a leucistic and blind cypriniform fish (Oreonectes daqikongensis, Nemacheilidae) that inhabits karst caves in Guizhou, China. Based on data from the mitochondrial ND4, ND5, and Cytb genes, we show that the divergence between O. daqikongensis and its most closely related pigmented species occurred ca. 6.82 million years ago (95% HPD, 5.12–9.01), providing ample time for widespread phenotypic change. Indeed, we found that the DNA sequence of Mc1r (melanocortin‐1 receptor), a key gene regulating the biosynthesis of melanin in most vertebrates, is pseudogenized in O. daqikongensis, caused by a 29 bp deletion in the protein‐coding region. Furthermore, 99,305 unigenes were annotated based on the transcriptome of skin tissue of Oreonectes fish. Among the differentially expressed unigenes, 7,326 (7.4% of the total unigenes) had decreased expression and 2,530 (2.5% of the total unigenes) had increased expression in O. daqikongensis skin. As predicted, the expression of Mc1r and 18 additional genes associated with melanin biosynthesis was significantly downregulated in the skin tissue of O. daqikongensis, but not in its congener. Our results, integrating with other studies on cavefishes, suggest that loss of pigmentation was caused by coding region loss‐of‐function mutations along with widespread transcriptional changes, resulting from extended evolutionary time as a cave‐dwelling form

    Whole-genome sequencing of the snub-nosed monkey provides insights into folivory and evolutionary history

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    Colobines are a unique group of Old World monkeys that principally eat leaves and seeds rather than fruits and insects. We report the sequencing at 146× coverage, de novo assembly and analyses of the genome of a male golden snub-nosed monkey (Rhinopithecus roxellana) and resequencing at 30× coverage of three related species (Rhinopithecus bieti, Rhinopithecus brelichi and Rhinopithecus strykeri). Comparative analyses showed that Asian colobines have an enhanced ability to derive energy from fatty acids and to degrade xenobiotics. We found evidence for functional evolution in the colobine RNASE1 gene, encoding a key secretory RNase that digests the high concentrations of bacterial RNA derived from symbiotic microflora. Demographic reconstructions indicated that the profile of ancient effective population sizes for R. roxellana more closely resembles that of giant panda rather than its congeners. These findings offer new insights into the dietary adaptations and evolutionary history of colobine primates

    Preparation and Stability of Inorganic Solidified Foam for Preventing Coal Fires

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    Inorganic solidified foam (ISF) is a novel material for preventing coal fires. This paper presents the preparation process and working principle of main installations. Besides, aqueous foam with expansion ratio of 28 and 30 min drainage rate of 13% was prepared. Stability of foam fluid was studied in terms of stability coefficient, by varying water-slurry ratio, fly ash replacement ratio of cement, and aqueous foam volume alternatively. Light microscope was utilized to analyze the dynamic change of bubble wall of foam fluid and stability principle was proposed. In order to further enhance the stability of ISF, different dosage of calcium fluoroaluminate was added to ISF specimens whose stability coefficient was tested and change of hydration products was detected by scanning electron microscope (SEM). The outcomes indicated that calcium fluoroaluminate could enhance the stability coefficient of ISF and compact hydration products formed in cell wall of ISF; naturally, the stability principle of ISF was proved right. Based on above-mentioned experimental contents, ISF with stability coefficient of 95% and foam expansion ratio of 5 was prepared, which could sufficiently satisfy field process requirements on plugging air leakage and thermal insulation

    Enhanced performance of lithium-sulfur batteries with high sulfur loading utilizing ion selective MWCNT/SPANI modified separator

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    Lithium-sulfur (Li-S) battery has attracted remarkable attention owing to its high theoretical energy density. However, its commercialization is still hampered by the rapid capacity degradation which mainly originates from the polysulfides shuttle between the anode and cathode. In this paper, a functional multiwall carbon nanotube/sulfonated polyaniline (MWCNT/SPANI) modified separator is designed to enhance the electrochemical performance of the Li-S batteries with high sulfur loading. The MWCNT/SPANI-coated separator is highly permselective to Li+ but rejects the transportation of polysulfide anions. Besides, the MWCNT/SPANI coating can also work as an upper current collector and provides channels for electron and ion transport to enhance the sulfur utilization and ensure the reactivation of trapped active materials. With the ion selective MWCNT/SPANI-coated separator, the electrochemical performance of the Li-S batteries based on cathodes with high sulfur loading (5 mg cm−2) and high sulfur content (72 wt%) has been significantly improved. It delivers a reversible capacity of 913 mA h g−1 at the current density of 100 mA g−1 after 100 cycles, much higher than that of the cells with pristine Celgard separator. Hence, the ion selective MWCNT/SPANI modified separator is promising for developing high-performance Li-S batteries employing cathodes with high sulfur loading and high sulfur content

    Analysis of risk factors for persistent infection of asymptomatic women with high-risk human papilloma virus

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    Objective: This study aims to prevent persistentinfection, reduce the incidence of cervical cancer, and improve women's health by understanding the theoretical basis of the risk factors for continuous infection of asymptomatic women with high-risk human papilloma virus (HPV) strains via information collected, which includes the persistent infection rate and the most prevalent HPV strain types of high risk to asymptomatic women in the high-risk area of cervical cancer in Linfen, Shanxi Province. Methods: Based on the method of cluster sampling, locations were chosen from the industrial county and agricultural county of Linfen, Shanxi Province, namely the Xiangfen and Quwo counties. Use of the convenience sampling (CS) method enables the identification of women who have sex but without symptoms of abnormal cervix for analyzing risk factors of HPV-DNA detection and performing a retrospective questionnaire survey in these 2 counties. Firstly, cervical exfoliated cell samples were collected for thin-layer liquid-based cytology test (TCT), and simultaneously testing high-risk type HPV DNA, then samples with positive testing results were retested to identify the infected HPV types. The 6-month period of testing was done to derive the 6-month persistent infection rate. The retrospective survey included concepts addressed in the questionnaire: basic situation of the research objects, menstrual history, marital status, pregnancy history, sexual habits and other aspects. The questionnaire was divided into a case group and a comparison group, which are based on the high-risk HPV-DNA testing result to ascertain whether or not there is persistent infection. Statistical analysis employed Epidate3.1 software for date entry, SPSS17.0 for date statistical analysis. Select statistic charts, Chi-Square Analysis, single-factor analysis and multivariate Logistic regression analysis to analyze the protective factors and risk factors of high-risk HPV infection. Risk factors are predicted by using the classification tree. Results: 3000 women participated in the study. The high-risk type HPV infection rate was 8.7%, the persistent infection rate was 7.5%. The persistent infection rates for the 2 age groups (ages 18–26 and 27–30) were 6.9% and 8.7%. The persistent infection rates of Xiangfen county were 7.4% and 7.4% respectively, and those of Quwo county were 7.8% and 11.6% respectively; there was no significant difference between each pair of groups. Single risk-factor analysis showed that first-time sex at age under 20, high school/technical secondary school education or above, multiple sexual partners, having more than 2 sexual partners in the past 6 months, oral sex, and colitis are the risk factors of high-risk type HPV infection. Multivariate analysis showed that the number of sexual partners, smoking and oral sex had an effect on HPV infection. The risk of HPV infection from smoking was 5.0-fold higher, and the risk of HPV infection from oral sex was 6.1-fold higher. Having more than 2 sexual partners increase the risk of HPV infection. By the predicated model analysis, the probability of HPV conveyed by oral sex was 14.8%; if the sexual companion number was zero or more than 2 without oral sex, the probability of HPV infection was 12.1%; if there was one sexual partner who smokes without oral sex, the probability of infection was 18.6%; if there was one sexual partner who does not smoke and without oral sex, the probability of infection was 3.6%. Conclusion: The persistent infection rate of asymptomatic women for high-risk type HPV is lower than those women in all ages. High-risk type HPV infection risk factors include the number of sexual partners, oral sex and smoking. Thus, young women may be able to reduce the risk of infection with high-risk type HPV by reducing the number of sexual partners, forming a correct sexual life habit, and avoiding smoking

    In situ growth of amorphous Fe2O3 on 3D interconnected nitrogen-doped carbon nanofibers as high-performance anode materials for sodium-ion batteries

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    In this work, a novel porous amorphous Fe2O3/nitrogen-doped carbon composite as a promising anode material for sodium-ion batteries has been fabricated by in situ growing amorphous Fe2O3 on 3D interconnected nitrogen-doped carbon nanofibers. The as-prepared composite exhibits superior sodium storage properties. It delivers a high reversible capacity of 408 mA h g−1 after 350 cycles at a current density of 100 mA g−1 and a good rate capability of 183 mA h g−1 at 3 A g−1. The excellent electrochemical performance is owing to the synergistic effects of the amorphous structure of Fe2O3 and the 3D interconnected nitrogen-doped carbon network with high nitrogen doping content (10 atom%), which do not only relieve the internal stress of the electrode and accommodate more electrochemical active sites for Na+ storage, but also buffer the volume changes of amorphous Fe2O3 as well as facilitate the electronic and ionic transportation during cycling
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