Effect of methylenetetrahydrofolate reductase C677T polymorphism on serum folate but not vitamin B12 levels in patients with H-type hypertension

Molecular Biology Reports - Hyperhomocysteinemia (HHcy) is a common complication in Chinese hypertensive patients and associated with methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism,...     

模拟降雨变化对古尔班通古特沙漠土壤养分及酶活性的影响

土壤酶参与土壤系统的养分循环过程,是联系植物和土壤养分的关键纽带。土壤酶活性对降水格局变化响应敏感,这种响应对于缺水且养分贫瘠的荒漠生态系统显得尤为重要。然而,早春积雪完全融化后首次降雨时间及降雨量如何影响土壤养分及土壤酶活性还鲜见相关报道。以新疆古尔班通古特沙漠为研究区,在早春积雪完全融化后,设置3个首次降雨时间(积雪完全融化后第10天、20天和30天)和3个降雨梯度(5 mm、10 mm和15 mm),于植物生长旺季采集土壤样品,研究土壤养分含量和土壤酶活性的响应特征。结果表明：积雪完全融化后不同首次降雨时间下5mm降雨处理以及积雪完全融化后第30天下各降雨量处理对土壤养分和酶活性影响不显著。积雪完全融化后第10天,随降雨量增加,土壤全碳呈显著先下降后增加趋势,全钾呈显著增加趋势,而土壤微生物量碳呈显著降低趋势;积雪完全融化后第20天,随降雨量增加,速效氮、土壤蔗糖酶活性、土壤微生物量碳氮呈先下降后增加趋势,土壤全碳和多酚氧化酶活性显著下降,土壤全钾和碱性磷酸酶活性显著增加。模拟10 mm降雨,随首次降雨时间推迟,土壤全氮、速效氮、速效磷、土壤蔗糖酶活性和土壤微生物量碳呈增加趋势;...     

Mesorhizobium ventifaucium sp. nov. and Mesorhizobium escarrei sp. nov., two novel root-nodulating species isolated from Anthyllis vulneraria

Ten mesorhizobial strains isolated from root-nodules of Anthyllis vulneraria by trapping using soils from southern France were studied to resolve their taxonomy. Their 16S rDNA sequences were identical and indicated that they are affiliated to the genus Mesorhizobium within the group M. prunaredense/M. delmotii/M. temperatum/M. mediterraneum/M. wenxiniae and M. robiniae as the closest defined species. Their evolutionary relationships with validated species were further characterized by multilocus sequence analysis (MLSA) using 4 protein-coding housekeeping genes (recA, atpD, glnII and dnaK), that divides the strains in two groups, and suggest that they belong to two distinct species. These results were well-supported by MALDI-TOF mass spectrometry analyses, wet-lab DNA-DNA hybridization (≤58%), and genome-based species delineation methods (ANI < 96%, in silico DDH < 70%), confirming their affiliation to two novel species. Based on these differences, Mesorhizobium ventifaucium (STM4922^T = LMG 29643^T = CFBP 8438^T) and Mesorhizobium escarrei (type strain STM5069^T = LMG 29642^T = CFBP 8439^T) are proposed as names for these two novel species. The phylogeny of nodulation genes nodC and nodA allocated the type strains into symbiovar anthyllidis as well as those of M. metallidurans STM2683^T, M. delmotii STM4623^T and M. prunaredense STM4891^T, all recovered from the same legume species.     

间伐强度对阿尔泰山天然林下植被的影响

以阿尔泰山天然林为研究对象,探究不同间伐强度（19%、33%、55%、62%）对林下植被的影响,为该区天然林的经营管理提供理论依据。运用样地调查法,对间伐30 a后的林木进行每木检尺,调查林下植被结构、物种多样性,对测定数据进行单因素方差分析和LSD多重比较检验。结果表明：（1）草本层物种丰富度随间伐强度的增大而增大,62%间伐强度显著大于其他处理;灌木层物种丰富度随间伐强度的增大呈先增后减的趋势,55%间伐强度最大（P>0.05）;不同间伐强度处理之间,林下植被的Simpson指数、Shannon-Wiener指数和Pielou均匀度指数均无显著差异（P>0.05）,草本植物优势种各间伐强度之间大致相同;（2）适当增加间伐强度可以明显提高灌木层和草本层密度,以55%间伐强度为优（P<0.05）,林下植被的盖度随着间伐强度的增大先增后减,间伐显著影响灌木植物盖度,而对草本层盖度则影响不显著（P>0.05）。以上研究表明从恢复林地多样性的角度考虑,间伐强度选取55%更合理。     

Chronic metformin intake and gastric cancer: A pooled analysis within the Stomach cancer Pooling (StoP) Project

IntroductionThe association between chronic use of metformin and risk of gastric cancer (GC) has been investigated with contradicting results. We aimed to study the association between chronic use of metformin and GC by using data from the Stomach cancer Pooling (StoP) Project, an epidemiological consortium of case-control studies on GC.MethodsData from three studies of the StoP Project with available information on metformin intake were analyzed.Multivariable logistic regression models were used to estimate study-specific odds ratios (ORs) and 95% confidence intervals (CIs) for the association between chronic use of metformin and GC risk. Analyses were adjusted for sex, age, socioeconomic status, body mass index, smoking status, alcohol drinking status, and history of diabetes. Study-specific ORs and 95% CIs were then pooled with a random-effects model.The dose-response relationship between the duration of metformin intake and GC was assessed with a one-stage logistic model, and the duration of intake was modelled using second-order fractional polynomials.ResultsThe OR of GC in metformin users versus non-users was 1.01 (95% CI=0.61, 1.67). The association between metformin and GC did not change among different strata of study participants’ characteristics or when restricting the analyses to those with a history of diabetes.The dose-response analysis showed a slightly reducing trend in the OR of GC and a borderline significant association with increasing duration of metformin intake.ConclusionsThe results of our study do not clearly support an association between chronic use of metformin and GC, warranting further research.     

The effect of age on the opportunity to receive cancer treatment

IntroductionOlder adults with cancer may not receive the same opportunities for treatment as younger patients. In this retrospective population-based cohort study, we explored whether age was an independent predictor of receiving specialist consultation and treatment.MethodsPatients age 45–99 were identified from the Ontario Cancer Registry having a primary solid tumor diagnosed between 01/Jan/2010 and 31/Dec/2019. We used logistic regression adjusted sociodemographic and clinical characteristics to compare the likelihood of consultation or receipt of treatment using linear splines at critical ages of 65, 80, and 90 years.ResultsA total 168,232 (42%), 165,205 (41%), 57,360 (14%), and 7810 (2%) patients were diagnosed age 45–64, 65–79, 80–89, and 90–99, respectively. The likelihood of surgical consultation decreased as patients reached 65 years [adjusted odds ratio (aOR) 0.86 (0.84–0.89)], which decreased further among octogenarians [aOR 0.63 (0.59–0.67)]. Similar results were observed for consultation with a medical oncologist and radiation oncologist. Receipt of surgery also decreased with age. Three-month post-operative mortality was higher among older patients [aRR 1.38 (1.26–1.50) per 10 years, p < 0.0001], an effect that remained similar as patients reached age 65 + years of age (p = 0.09 for change). For stage I patients, 3-month post-operative survival was high across all age groups, ranging from 99.8% in 45–64 year-olds, 99.4% in 65–79 year-olds, and 98.1% among octogenarians and nonagenarians (lung, colorectal, breast, cervical cancer patients).ConclusionOlder patients were less likely to have specialist consultations. More comprehensive data collection on clinical factors and referral patterns is needed to improve care for elderly cancer patients.     

Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus) in Western China

Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called “the many-eyes effect”, together with the “encounter dilution effect”, is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus) in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups’ disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection.     

沼泽、盐化沙丘过渡带和沙丘生境下芦苇的光合及生理生化特性

对于田地区3种不同生境(沼泽、盐化沙丘过渡带和沙丘顶)芦苇的生长环境特征、光合特性、渗透调节及抗氧化系统的特征进行研究。结果表明:芦苇叶片的Pn日变化在沼泽生境呈单峰曲线,在盐化沙丘过渡带和沙丘顶部均为双峰曲线,光合"午休"现象明显,气孔导度降低是其主要原因。脯氨酸和可溶性糖含量随根区土壤水分减少和盐分加剧增加显著,其中可溶性糖含量变化剧烈,对抵御干旱和盐渍化危害的贡献较大。芦苇叶片超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性随干旱及盐分加剧增加显著,两者对水分亏缺的响应较盐分敏感,且可有效缓解沙丘生境由于缺水所造成的氧化损伤,使丙二醛(MDA)含量维持在相对较低水平。过氧化物酶(POD)活性在沙丘和盐渍化生境内都比较高,对抵抗盐渍化和干旱起着同样重要的作用。     

准噶尔荒漠大翅霸王的生殖物候及结实格局

大翅霸王是多年生早春开花草本植物,是准噶尔荒漠地区的建群种之一。对野生大翅霸王的生殖物候、果实形态、结实格局和种子萌发特性进行了研究。结果表明:(1)大翅霸王的营养期生长期为20—30d,占整个生活周期的1/4,生殖生长期长约90—100d,其中花期约占1/2,果熟期短;(2)大翅霸王种群能产生3种形态的果实,可将植株分为5翅型、4/5翅型和3/4/5翅型植株,它们分别占种群植株数的3.45%、83.15%和13.40%。(3)依据个体大小的变化,3种类型果实在植株上的比例发生了显著变化。随植株个体的增大,三翅果所占比例逐渐增多,由0增加到2.65%;四翅果所占比例也增多,但在二级个体上有最大比例17.01%;五翅果实所占比例最高(80%)且没有显著变化。(4)三翅果、四翅果和五翅果内种子形态无差异,萌发率均小于30%;划破种皮能不同程度的加速和促进种子的萌发。大翅霸王特有的生殖物候和果实的表型多样性是其对荒漠干旱地区恶劣多变环境长期适应的结果。