Enterococcus faecalis provides protection during scavenging in carrion crow (Corvus corone)

The gut microbiota significantly influences host physiology and provides essential ecosystem services.While diet can affect the composition of the gut microbiota,the gut microbiota can also help the host adapt to specific dietary habits.The carrion crow(Corvus corone),an urban facultative scavenger bird,hosts an abundance of pathogens due to its scavenging behavior.Despite this,carrion crows infrequently exhibit illness,a phenomenon related to their unique physiological adaptability.At present,however,the role of the gut microbiota remains incompletely understood.In this study,we performed a comparative analysis using 16S rRNA amplicon sequencing technology to assess colonic content in carrion crows and 16 other bird species with different diets in Beijing,China.Our findings revealed that the dominant gut microbiota in carrion crows was primarily composed of Proteobacteria(75.51%)and Firmicutes(22.37%).Significant differences were observed in the relative abundance of Enterococcus faecalis among groups,highlighting its potential as a biomarker of facultative scavenging behavior in carrion crows.Subsequently,E.faecalis isolated from carrion crows was transplanted into model mice to explore the protective effects of this bacterial community against Salmonella enterica infection.Results showed that E.faecalis down-regulated the expression of pro-inflammatory cytokines tumor necrosis factor alpha(TNF-α),interferon gamma(IFN-γ),and interleukin 6(IL-6),prevented S.enterica colonization,and regulated the composition of gut microbiota in mice,thereby modulating the host’s immune regulatory capacity.Therefore,E.faecalis exerts immunoregulatory and anti-pathogenic functions in carrion crows engaged in scavenging behavior,offering a representative case of how the gut microbiota contributes to the protection of hosts with specialized diets.

An initial study of insect succession on decomposing rabbit carrions in Harare,Zimbabwe

Objective:To investigate insects visiting sun exposed and shaded decomposing rabbit carcasses and to establish the relationship between insects and carcasses which may be of forensic importance in Harare.Methods:Two rabbits weighing 2.3 kg and 2.5 kg were killed by sharp blows on the head.One was exposed to the sun while the other was placed under shade.The carcasses were allowed to decompose and insects were collected twice a day for the first week and thereafter once a day up to the end of the 7 weeks.Maggots were also collected from the decomposing carcasses and reared.Results:Five dipteran families(Galliphoridae,Muscidae,Sarcophagidae,Phoridae and Drosophilidae)were identified from the sun-exposed carcass.Species collected included Lucilia cuprina(L.cuprina),Chrysomya albiceps(C.albiceps),Musca domestica,Sarcophaga sp.and Drosophila sp.Four families(Calliphoridae,Muscidae,Phoridae,Anthomyiidae)were identified from the shaded carcass.Representatives of these families included L cuprina,C.albiceps,Musca domestica,and Hydrotaea sp.Three Coleopteran families(Histeridae,Cleridae and Dermestidae)were identified from hodt carcasses.The observed species were Saprinus sp,Necrobia rufipes and Dermestes sp.Fomicidae(Hymenoptera)was represented by only one species(Pheidoie sp.)Flies which emerged from the rearing units were L cuprina,Lucilia sp.,C.albiceps,Sarcophaga sp.and Sepsis sp.).Conclusions:Of the dipteran species collected during the study,L cuprina and C.albiceps could be important for further forensic studies since they were collected from the carcasses and also observed from the rearing units.

Competition of insect decomposers over large vertebrate carrion:Necrodes beetles(Silphidae)vs.blow flies(Calliphoridae)

Large carrion is inhabited by highly variable and interactive communities of insects.Positive interactions in carrion insect communities have been recently the focus in carrion ecology.In contrast,competition between carrion insects is rather undervalued.Here we provide evidence that blow flies(Calliphoridae)and Necrodes beetles(Silphidae),dominant decomposers of large carcasses in terrestrial habitats,compete over carrion.By reanalyzing the results from 90 pig carcasses,we demonstrated that the contribution of the flies and the beetles to the decay was negatively related.The greater part of the large carrion pool was monopolized by blow flies,whereas Necrodes beetles abundantly colonized carcasses,on which blow flies were less effective as decomposers.In behavioral assays,we found that adult beetles killed 4 times more frequently feeding than postfeeding third instar larvae of the flies,with the large decrease in the killing frequency after the larvae reached the age of early third instar.Therefore,adult Necrodes beetles preferentially killed the larvae that were before or in their peak feeding.The study provides evidence that the interaction between blow flies and Necrodes beetles is a combination of indirect exploitative effects of the flies and direct interference effects of the beetles(the mixed competition).

Carrion’s disease: an eradicable illness?

Carrion’s disease is a neglected tropical disease caused by Bartonella bacilliformis,a vector-borne pathogen restricted to the Andean valleys of Peru,Ecuador and Colombia.Carrion’s disease is a biphasic illness;in the acute phase the case-fatality rate can be as high as 88%,related to high parasitemia,arriving to almost all erythrocytes,and secondary bacterial infections close related with the development of transient immunosuppression in the earlier illness phases.In addition,there are an undefined number of asymptomatic carriers that are reservoirs of the etiological agent of Carrion’s disease in endemic areas,they make take into account due to they are the perpetuators of this disease.The actual scenario of Carrion’s disease,in which the illness is arriving to new areas,due to the expansion of the vector’s distribution,suggests that now may be a crucial time to design a strategy focusing on its elimination.

双向凝胶电泳图谱用于常见尸食性蝇类初孵幼虫的鉴别

双向凝胶电泳分析技术已在生物科学各领域被广泛应用,蛋白质组作图的意义已经日益显现。通过对4种常见尸食性蝇类初孵幼虫蛋白质组双向凝胶电泳和图象分析,发现各种类间双向凝胶电泳图谱差异显著,并对相应的等电点和相对分子量进行聚类和判别分析,结果表明,建立合适的尸食性蝇类初孵幼虫的双向凝胶电泳图谱可用于鉴别形态学极易混淆的昆虫种类。

沈阳地区室内常见尸食性蚤蝇幼期识别

利用尸食性蝇类发育生物学推断死后间隔时间的前提是对其幼期种属的准确鉴定。本文对沈阳地区室内常见的4种尸食性蚤蝇幼期的主要形态特征进行了描述。结果表明:根据其口器、体壁突起、气门和呼吸角等特征不仅可以区分虫龄,还可以鉴别4种蚤蝇。

Gastric acid level of humans must decrease in the future

Proton pump inhibitors strongly inhibit gastric acid production,but digestion problems do not generally arise.We can intake almost ordinary food even after total gastrectomy.Small intestine itself can digest and absorb food using various digestive enzymes without digestion in the stomach.The pH level of gastric acid in humans is much lower than that of most animals,and very close to that of carrion-eating animals called scavengers.It is assumed that ancient humans became bipedal approximately 4 million years ago.It was difficult for humans,who just started unstable bipedal locomotion,to catch quadrupedal-walking animals that can move faster,without special hunting tools.They may have eaten remaining carcasses,which is mainly the leftovers of carnivora species,as animalderived food.The benefit to produce a volume of gastric acid for humans is carrion eating,in which disinfection by gastric acid is important.Humans produce a high concentration of gastric acid to enable consumption of a diet containing some bacteria and support this lifestyle by consuming significant energy to protect themselves from gastric acid.Now,the opportunity for strong deleterious bacteria to enter the gastrointestinal tract has decreased because of the organized clean environment.If this hygienic environment is maintained for a long time,our gastric acid level must be decreased gradually.

利用尸食性蚤蝇推断死亡时间的法医学研究进展

死亡时间的准确推断一直是法医学的难题。昆虫学方法已被认为是死亡时间推断的有效方法。尸食性蝇类发育生物学在死亡时间推断中有着重要地位。蚤蝇体形微小,在相对密闭的空间,可成为尸体上主要的甚至是唯一的昆虫证据。本文从尸食性蚤蝇的作用、种属鉴定以及日龄推断方面,综述了利用尸食性蚤蝇推断死亡时间的法医学研究进展。

中国东北地区小型鸟类尸体分解利用的分析

为研究分解利用小型鸟类尸体的主要动物类群,比较其对尸体的利用情况和分布差异,在我国东北黑龙江省尚志市帽儿山林场投放120只死亡的雏鸡,通过捕虫及红外相机监控等方法记录到所有出现的动物种类共计5纲8目18科28种。尸体于投放第8天全部丢失,其中针阔混交林中尸体丢失的速度最快,投放第1天的存留时间期望值最低;阔叶林、人工红松林次之;草地尸体丢失的速度最慢,存留时间期望值最高。尸体的丢失可分为被埋葬虫掩埋、被鸟兽食用和被蝇类幼虫食用3种情况,其中被埋葬虫埋葬的尸体占55%,被鸟兽食用的尸体占12%,被蝇类幼虫食用的尸体有占33%。埋葬虫完全利用尸体的速度最快,数量占55%;鸟兽次之,蝇类最慢。埋葬虫主要分布在针阔混交林和阔叶林,而草地生境无分布。

中医药治疗疮疡简况

疮疡外部形态可分为肿疡和溃疡,不同阶段形态、用药不同,外用药为主。治疗不外乎消、托、补三大法则。包括局部用药与复方(清热活血化瘀、除湿排脓、敛疮收口),其他(单味中药、外用药实验研究、灸法、针刺等)。疮疡初期,皮肤表面红、肿、热、痛,高于皮肤表面,即肿疡成型期,主要消、托、补中消;中后期疮疡除湿排脓,袪腐生新。初期内服药物:黄连、黄柏、苦参、夏枯草、龙胆草等清热解毒,配红霉素、金霉素软膏等消肿止痛。疮疡早期失治到达中期肿疡,应尽早切开引流使脓毒排出,托、补结合,配针灸;疮疡后期素体虚弱,补法合除湿,配生肌膏袪腐生新。

一种新型弯管传输辊道

介绍了一种新型、实用的弯管传输辊道的结构和参数设计,该辊道结构简单,经济实用,换道时间短,应用于弯管防腐生产线中,较好地解决了弯管抛丸除锈和涂层防腐时的不均匀问题。

中医学“腐”的语义内涵探赜

中医学根植于传统文化,术语内涵常随之而变迁。“腐”为中医学一词多义的典型,文章梳理古代文献,发现其概念起源于自然界物质发酵或败烂的过程、形态、气味,以及冬月祭祀的“朽臭”。中医衍生其含义:生理层面,涵盖体内固精培元、疏利秽浊之“腐臭”真气,以及水火共作而发生的“腐熟”消化过程。病理层面,“腐秽”作为病因,代指自然界臭败之浊气,以及体内郁滞之糟粕、湿浊、食积、瘀血、水饮;“腐肉”形容体表具有毒、瘀属性的病理产物“死肉”;“热蒸肉腐”描述痈疽热壅致瘀、毒热灼血、蒸变致腐、炼液成脓的病机。症的层面,含人体散发的秽浊之气,以及腐秽之气体现于舌面的“腐苔”。药性层面有化物藏元、除固导浊之“腐臭”。

中医综合外治方案治疗糖尿病足溃疡期疗效观察

目的评价糖尿病足溃疡期中医综合外治方案的疗效。方法将5家分中心的190例糖尿病足溃疡期Ⅱ-Ⅳ级患者随机分为治疗1组63例、治疗2组67例、对照组60例。各组患者均采取控制血糖、抗感染治疗,治疗1组和治疗2组均采用中医综合外治方案,两组所选外治药物的药物名称、功效相同但生产厂家不同;对照组采用西医外治方案,各组治疗周期为8周。分别于治疗前后对各组患者症状进行评分,观察临床疗效。结果治疗1组临床痊愈率65.08%、显效率14.29%、有效率15.87%、无效率4.76%;治疗2组临床痊愈率67.16%、显效率19.40%、有效率13.43%、无效率0;对照组临床痊愈率46.67%、显效率13.33%、有效率33.33%、无效率6.67%。治疗1组、2组与对照组疗效等级比较差异均有统计学意义(P<0.05),治疗1组与治疗2组中医证候疗效等级比较差异无统计学意义(P>0.05)。结论中医综合外治方案治疗糖尿病足溃疡期疗效确切。

实时荧光定量TaqMan-MGB探针法检测杆菌样巴尔通体

【目的】应用Taq Man探针实时荧光定量PCR技术建立特异性强、敏感性高和稳定性好的快速杆菌样巴尔通体检测方法。【方法】应用生物信息学方法查找杆菌样巴尔通体特有基因,从中筛选出一段特有的基因序列为模板设计探针和引物。通过比较Ct值和荧光强度确定扩增反应的最佳退火温度、探针和引物浓度;将扩增产物连接到p EASY-T载体上制备标准品,绘制标准曲线,分析扩增效率和线性关系;评估方法的特异性、敏感性及重复性。【结果】优化后退火温度为60°C,探针和引物浓度均为200 nmol/L,反应体系20μL。特异性实验显示只有杆菌样巴尔通体扩增出荧光信号,其他种属细菌均未见荧光信号;标准曲线线性关系良好(R2=1),扩增效率E=98.18%;最低检出限为每个PCR反应3个拷贝;组内和组间的变异系数CV值分别为0.21%–0.42%和0.29%–0.59%,在允许范围内。【结论】研究建立的实时荧光定量Taq Man-MGB探针法特异性强、灵敏度高、稳定性好,可快速检测鉴定杆菌样巴尔通体,为这种巴尔通体所引起的一系列疾病的早期快速诊断、监测和流行病学调查等研究提供有效手段。

分离CEO两职合一:代理问题缓和与战略继任的开始

董事会分离原本两职合一的领导权结构包含了充分的信息传递过程。基于代理理论,从董事会开启分离决议的视角,探讨以企业价值变动为主导的董事会分离两职合一决策的内在机理。以2006年至2013年中国沪、深两市A股上市公司为样本,选择董事会领导权变更数据,通过构建Probit和Logistic模型回归进行实证研究。研究结果表明,董事会领导权结构中董事长与CEO两职合一向分离转化并不都是企业在价值下降时出于缓和代理问题所致。两职合一向分离转化时,企业价值越高,越倾向于一种过渡形式的分离,即学徒式分离,这是基于企业战略继任的需要;两职合一向分离转化时,企业价值越低,则越倾向于离职式分离和降职式分离,顺应了企业缓和代理问题的需要。进一步的研究表明,独立董事对于董事会的分离决议没有明显促进作用,而高管个人职业生涯潜力对于董事会分离决议有明显的调节作用。上市公司两职合一向分离转化随着类型不一所传递的信息不同,包含了价值变动、战略继任和代理问题等多种信息。

Is aggregated oviposition by the blow flies Lucilia sericata and Phormia regina （Diptera： Calliphoridae） really pheromone-mediated？

When female blow flies Lucilia sericata and Phormia regina （Diptera： Cal- liphoridae） oviposit in aggregations on carrion, even-aged larval offspring reportedly de- velop faster, and fewer are parasitized or preyed upon. The benefits of aggregated ovipo- sition equally affect con- and heterospecific larvae sharing a resource. The benefits imply that female blow flies engage in coordinated, pheromone-mediated oviposition behavior. Yet, repeated attempts to identify oviposition pheromones have failed invoking doubt that they exist. Simply by regurgitating and feeding on carrion, flies may produce attractive semiochemicals. If flies were to aggregate in response to feeding flies rather than oviposit- ing flies, then the semiochemical cue（s） may be associated with the salivary gland. Working with L. sericata and P.. regina and using liver as a surrogate oviposition medium, we test the hypotheses, and present data in their support, that （i） gravid or nongravid females ovipositing and/or feeding on liver enhance its attractiveness to gravid and nongravid fe- males; （ii） females respond to semiochemicals from feeding heterospecific females; （iii） females respond equally well to semiochemicals from feeding con- and heterospecific females; （iv） macerated head tissues of females applied to liver enhance its attractiveness; and （v） females in direct contact with and feeding on liver, but not when next to yet physically separated from liver, enhance attraction of flies. We conclude that oviposition site-seeking females do not respond to an oviposition pheromone. Instead, they appear to coopt semiochemicals associated with feeding flies as resource indicators, taking chances that resources are suitable for oviposition, and that ovipositing flies are present.

Benefits of heterospecific aggregation on necromass: in fluence of temperature, group density, and compositi on on fitness-related traits

Necrophagous blowflies(Diptera:Calliphoridae)such as Calliphora vicina,a cold-tolerant species,and L ucilia serie ata,a warm-adapted species,are pioneer carrion・breeder.Although these two species have different temperature preferences,larvae aggregate actively and often feed simultaneously on carrion.The hypothesis to be tested was that L.sericata benefits from the association with C.vicina at lower temperatures(i.e.,15℃)and that C.vicina derives greater benefits from this association at higher temperatures(i.e.,28℃).Therefore,both species were raised at these two constant temperatures from first instars to adults under three different conditions:monospecific low-density,monospecific high-density,and heterospecific high-density.The time until larval migration,surface area of puparia,and survival rates were determined for each condition.Differences between these fitness-related traits were found between species,temperatures,group densities,and species compositions.At 28°C,C.vicina larvae bred in heterospecific groups migrated significantly earlier and in higher numbers than that under same density conspecific con・ditions,with a lower mortality rate.At 15°C,both species benefited from high-density heterospecific associations,expressed by faster development and larger puparia.In conclusion,necrophagous larvae benefited from heterospecific aggregations at suboptima 1 temperatures by adapting their migration time to that of the faster species.Since temperature changes throughout the day and over the year,the beneficiary of such a collective association also changes.The costs involved and deviations to the temperature-size rule highlight the complexity of the carrion ecosystem.

Effect of carcass contamination on necrophagous invertebrate performance

Background:The breakdown of dead organic matter is driven by a diverse array of organisms and is an important process increasingly impacted by a range of contaminants.While many studies have documented how contaminants affect food webs that are fueled by decaying plant litters,much less is known about how contaminants affect organisms that rely on dead animal material.Here,we begin to explore the effects of food contamination—using silver nanoparticles(AgNPs)as a model contaminant—on the carrion beetle Nicrophorus vespilloides that buries carcasses of small vertebrates in soils as food source and larval nursing grounds.Results:Our data show that a single ingestion of a non-lethal dose of 1μg mL^(−1) AgNPs by adult female beetles does not affect overall gut microbial activity but results in shifts in the gut microbial community composition towards pathogens including Alcaligenes,Morganella,and Pseudomonas.While no effects were observed in offspring clutch size,some reductions were visible in clutch weight,number of larvae,and number of eclosing pupae in exposed N.vespilloides in comparison with controls.Repeated ingestion of AgNPs over several weeks led to a decrease in survival of adult beetles,suggesting that more environmentally realistic exposure scenarios can directly affect the success of carcass-feeding animals.Conclusions:Sub-lethal carcass contamination with a model pollutant can affect the gut microbial composition in female beetles and reduce offspring fitness.This encourages consideration of currently overlooked propagation routes of contaminants through necrophagous food webs and inherent consequences for ecological and evolutionary processes.

A review of experimental design in forensic taphonomy:moving towards forensic realism

Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for sci-entific data to be admissible in court.In response,there has been a shift towards quantifica-tion of methodology and estimating the postmortem interval.Despite these advances,there are still biases and limitations within the discipline not explicitly addressed in the early stages of experimental design nor in final published works.In this article,unresolved debates with respect to the conductance and reporting of forensic taphonomic research are reviewed,beginning with the nature of experimental cadavers,human or animal analogues and their body size,and second,the forensic realism of experimental setups,specifically with respect to caging,clothing and number of carcases.Pigs,albeit imperfect,are a good model to gain a general idea of the trends that may be seen in humans in subsequent validation studies in facilities where human donors are available.To date,there is no consen-sus among taphonomists on the extent of the effect that body mass has on decomposition progression.More research is required with both human cadavers and non-human analogues that builds on our current knowledge of forensic taphonomy to answer these nagging questions.This will enable the discipline to make the reliable assumption that pigs and donor decomposition data can be applied to homicide cases.A suite of experimental design aspects is suggested to ensure systematic and standardized data collection across differ-ent biogeoclimatic circumstances to identify and quantify the effects of potential confounding variables.Such studies in multiple,varied biogeographic circumstances with standardized protocols,equipment and carrion will facilitate independent global validation of patterns.These factors are reviewed to show the need for adjustments in experimental design to ensure relevance and applicability of data within locally realistic forensic situations.The initiation of a global decomposition data network for forensic taphonomists is recommended.

Recent advances in forensic anthropology:decomposition research

Decomposition research is still in its infancy,but significant advances have occurred within forensic anthropology and other disciplines in the past several decades.Decomposition research in forensic anthropology has primarily focused on estimating the postmortem interval(PMI),detecting clandestine remains,and interpreting the context of the scene.Additionally,while much of the work has focused on forensic-related questions,an interdisciplinary focus on the ecology of decomposition has also advanced our knowledge.The purpose of this article is to highlight some of the fundamental shifts that have occurred to advance decomposition research,such as the role of primary extrinsic factors,the application of decomposition research to the detection of clandestine remains and the estimation of the PMI in forensic anthropology casework.Future research in decomposition should focus on the collection of standardized data,the incorporation of ecological and evolutionary theory,more rigorous statistical analyses,examination of extended PMIs,greater emphasis on aquatic decomposition and interdisciplinary or transdisciplinary research,and the use of human cadavers to get forensically reliable data.