基于不同网格尺度福州主城区鸟类多样性与景观特征的关系研究

理解城市鸟类多样性与景观特征的关系对城市生物多样性保护和可持续发展具有重要意义。通过爬取中国观鸟记录中心网站2020年福州主城区436份观鸟报告数据计算鸟类丰富度指数(S)、Shannon-Wiener多样性指数(H)和Simpson多样性指数(D);基于谷歌地球引擎和高分辨率Worldview影像量化景观特征因子;在此基础上,采用Mann-Whitney U检验了两个网格尺度(300 m和1000 m)下S、H和D指数的差异性;运用广义线性模型探究了两个尺度下影响鸟类多样性指数的关键景观因子及其重要性。结果表明：(1)2020年研究区内共观测到242种鸟类,隶属19目59科,雀形目鸟类为优势种;数量占比从高到低依次为留鸟、冬候鸟、旅鸟和夏候鸟,分别为63.53%、25.83%、6.71%和3.93%;(2)两个尺度下鸟类多样性指数差异明显,1000 m尺度下S和H指数均显著高于300 m尺度(0.05相似文献   

茶毛虫天敌的研究

本明确了茶毛虫天敌种类及其优势种：寄生性天敌中寄生卵的有赤眼蜂和茶毛虫黑卵蜂,其中茶毛虫绒茧蜂是优势种;寄生幼虫的有茶毛虫绒茧蜂、茶毛虫瘦姬蜂、小孢瘦姬蜂、日本黄茧蜂和寄蝇等,其中茶毛虫绒茧蜂是优势种;捕食性天敌有步行虫、蠼螋、蜘蛛和青蛙等,其中蜘蛛是优势类群,白斑猎蛛为优势种。研究了茶毛虫主要寄生性天敌的寄生率和寄生动态：茶毛虫黑卵蜂的寄生率为１５－２０％,越冬卵可高达４５％左右;茶毛虫绒茧蜂     

Intra-Genomic Heterogeneity in 16S rRNA Genes in Strictly Anaerobic Clinical Isolates from Periodontal Abscesses

Background

Members of the genera Prevotella, Veillonella and Fusobacterium are the predominant culturable obligate anaerobic bacteria isolated from periodontal abscesses. When determining the cumulative number of clinical anaerobic isolates from periodontal abscesses, ambiguous or overlapping signals were frequently encountered in 16S rRNA gene sequencing chromatograms, resulting in ambiguous identifications. With the exception of the genus Veillonella, the high intra-chromosomal heterogeneity of rrs genes has not been reported.

Methods

The 16S rRNA genes of 138 clinical, strictly anaerobic isolates and one reference strain were directly sequenced, and the chromatograms were carefully examined. Gene cloning was performed for 22 typical isolates with doublet sequencing signals for the 16S rRNA genes, and four copies of the rrs-ITS genes of 9 Prevotella intermedia isolates were separately amplified by PCR, sequenced and compared. Five conserved housekeeping genes, hsp60, recA, dnaJ, gyrB1 and rpoB from 89 clinical isolates of Prevotella were also amplified by PCR and sequenced for identification and phylogenetic analysis along with 18 Prevotella reference strains.

Results

Heterogeneity of 16S rRNA genes was apparent in clinical, strictly anaerobic oral bacteria, particularly in the genera Prevotella and Veillonella. One hundred out of 138 anaerobic strains (72%) had intragenomic nucleotide polymorphisms (SNPs) in multiple locations, and 13 strains (9.4%) had intragenomic insertions or deletions in the 16S rRNA gene. In the genera Prevotella and Veillonella, 75% (67/89) and 100% (19/19) of the strains had SNPs in the 16S rRNA gene, respectively. Gene cloning and separate amplifications of four copies of the rrs-ITS genes confirmed that 2 to 4 heterogeneous 16S rRNA copies existed.

Conclusion

Sequence alignment of five housekeeping genes revealed that intra-species nucleotide similarities were very high in the genera Prevotella, ranging from 94.3–100%. However, the inter-species similarities were relatively low, ranging from 68.7–97.9%. The housekeeping genes rpoB and gyrB1 were demonstrated to be alternative classification markers to the species level based on intra- and inter-species comparisons, whereas based on phylogenetic tree rpoB proved to be reliable phylogenetic marker for the genus Prevotella.     

Keratinocyte growth factor‐2 intratracheal instillation significantly attenuates ventilator‐induced lung injury in rats

Preservation or restoration of normal alveolar epithelial barrier function is crucial for pulmonary oedema resolution. Keratinocyte growth factor‐2 (KGF‐2), a potent epithelial cell mitogen, may have a role in preventing ventilator‐induced lung injury (VILI), which occurs frequently in mechanically ventilated patients. The aim of the study was to test the role of KGF‐2 in VILI in rats. Forty healthy adult male Sprague‐Dawley rats were randomly allocated into four groups, where rats in Groups HVZP (high‐volume zero positive end‐expiratory pressure) and HVZP+KGF‐2 were given intratracheally equal PBS and 5 mg/kg KGF‐2 72 hrs before 4 hrs HVZP ventilation (20 ml/kg), respectively, while PBS and KGF‐2 were administered in the same manner in Groups Control and KGF‐2, which underwent tracheotomy only with spontaneous breathing. Inflammatory cytokines (tumour necrosis factor‐α, macrophage inflammatory protein 2), neutrophil and total protein levels in bronchoalveolar lavage fluid and surfactant protein mRNA expression in lung tissue were detected; the number of alveolar type II cells, lung water content and lung morphology were also evaluated. The results indicate that pre‐treatment with KGF‐2 showed dramatic improvement in lung oedema and inflammation compared with HVZP alone, together with increased surfactant protein mRNA and alveolar type II cells. Our results suggest that KGF‐2 might be considered a promising prevention for human VILI or other acute lung injury diseases.     

Novel artificial intelligence machine learning approaches to precisely predict survival and site-specific recurrence in cervical cancer: A multi-institutional study

BackgroundMachine learning (ML) has been gradually integrated into oncologic research but seldom applied to predict cervical cancer (CC), and no model has been reported to predict survival and site-specific recurrence simultaneously. Thus, we aimed to develop ML models to predict survival and site-specific recurrence in CC and to guide individual surveillance.MethodsWe retrospectively collected data on CC patients from 2006 to 2017 in four hospitals. The survival or recurrence predictive value of the variables was analyzed using multivariate Cox, principal component, and K-means clustering analyses. The predictive performances of eight ML models were compared with logistic or Cox models. A novel web-based predictive calculator was developed based on the ML algorithms.ResultsThis study included 5112 women for analysis (268 deaths, 343 recurrences): (1) For site-specific recurrence, larger tumor size was associated with local recurrence, while positive lymph nodes were associated with distant recurrence. (2) The ML models exhibited better prognostic predictive performance than traditional models. (3) The ML models were superior to traditional models when multiple variables were used. (4) A novel predictive web-based calculator was developed and externally validated to predict survival and site-specific recurrence.ConclusionML models might be a better analytic approach in CC prognostic prediction than traditional models as they can predict survival and site-specific recurrence simultaneously, especially when using multiple variables. Moreover, our novel web-based calculator may provide clinicians with useful information and help them make individual postoperative follow-up plans and further treatment strategies.     

LncDACH1 promotes mitochondrial oxidative stress of cardiomyocytes by interacting with sirtuin3 and aggravates diabetic cardiomyopathy

Science China Life Sciences - Diabetic cardiomyopathy (DCM) is a common complication in diabetic patients. The molecular mechanisms of DCM remain to be fully elucidated. The intronic long noncoding...