Genetic and biochemical aspects of quorum sensing in the bacterial lifestyle and pathogenesis

Quorum sensing is the biochemical communication system within bacterial cells which may instigate their virulence factors,and hence,is imperative for pathogenesis.Such a system optimizes metabolic and behavioral activities played by the densely populated bacterial community as well as the production of the concomitant response against diffusible or secreted signals.Thus,the multi-layered signal transduction networks of quorum sensing help bacteria acclimatize to the disadvantages by increasing their confrontation ability aided by biofilm formation.Previous studies unraveled the impact of quorum sensing in the microbial interactions both within a single species and between several species.The development of the synthetic ecological models has added advantages in the studies of microbial sociability in natural habitats as well as aided in drug designing.Current review highlighted the up-to-date knowledge on the basic mechanisms of quorum sensing and its influence to accelerate the bacterial resistance against different environmental stimuli or synthetic drugs along with the factors affecting the quorum sensing system,and the harmful role of quorum sensing in food spoilage.The information gathered in this review would be beneficial to understand the metabolic cross talk as well as the virulence traits of the pathogenic microorganisms in course of their pathogenesis augmented by quorum sensing.

IMPACT OF URBANIZATION ON STRUCTURE AND FUNCTION OF RIVER SYSTEM—Case Study of Shanghai,China

Urbanization can affect the physical process of river growth, modify stream structure and further influence the functions of river system. Shanghai is one of the largest cities in the world, which is located in Changjiang (Yangtze) River Delta in China. Since the 1970s, the whole river system in Shanghai has been planned and managed by the Shanghai Water Authority. The primary management objectives in the last 30 years have been to enhance irrigation and flood-control. By using Horton-Strahler classification and Horton laws as a reference, a novel method of stream classification, in conjunction with the traditional and specially designed indicators, was applied to understanding the structure and functions of the river system in Shanghai. Correlation analysis was used to identify the interrelations among indicators. It was found that the impact of urbanization on the river system was significant although natural laws and physical characteristics marked a super-developed river system. There was an obvious correlation between the degree of urbanization and the abnormal values of some indicators. Urbanization impacts on river system such as branches engineered out, riverbank concreting and low diversity of river style were widely observed. Each indicator had distinct sensibility to urbanization so they could be used to describe different characteristics of urban river system. The function indicators were significantly related to structure indicators. Stream structure, described by fractal dimension and complexity of river system, was as important as water area ratio for maintaining river’s multi-function.

Application of iron and silicon fertilizers reduces arsenic accumulation by two Ipomoea aquatica varities

A 45 d pot experiment was conducted to examine the effects of silicon fertilizer or iron fertilizer on the growth of two typical Ipomoea aquatica cultivars（Daye and Liuye） and arsenic（As） accumuation of Daye and Liuye grown in As-contaminated soils at different As dosage levels. The results showed that the application of these two fertilizers generally enhanced the growth of the plants, which may be partly attributable to the reduction in As toxicity. The addition of these two fertilizers also significantly reduced the uptake of As by the plants though the iron fertilizer was more effective, as compared to the silicon fertilizer. The accumulation of As in shoot portion was weaker for Daye than for Liuye. The research findings obtained from this study have implications for developing cost-effective management strategies to minimize human health impacts from consumption of As-containing I. aquatica.

A short review of the genes involved in the development and progression of colorectal cancer

The extent and aggression of colorectal cancer is a worldwide public health threat.Extensive research has been conducted on the pre-requisites leading to this fatal cancer.An array of genes along with their mutations and the signal transduction pathways leading to the cellular transformation into the cancerous cells have been investigated.Based on the knowledge gained so far,present review shortly discussed the role of the major genes especially those are involved in instigating abnormalities in the cellular cycles,cellular proliferation and differentiation.A simple but novel molecular scheme of the colorectal cancer development has also been plotted.

Increased susceptibility to Trichuris muris infection and exacerbation of colitis in Mdr1a-/-mice

AIM:To investigate the influence of Trichuris muris(T.muris)infection in a mouse model of genetic susceptibility to inflammatory bowel disease,Mdr1a-/-.METHODS:Mdr1a-/-mice were housed under specific pathogen free conditions to slow the development of colitis and compared to congenic FVB controls.Mice were infected with approximately 200 embryonated ova from T.muris and assessed for worm burden and histological and functional markers of gut inflammation on day 19 post infection.RESULTS:Mdr1a-/-mice exhibited a marked increase in susceptibility to T.muris infection with a 10-fold increase in colonic worm count by day 19 pi compared to FVB controls.Prior to infection,Mdr1a-/-exhibitedlow-level mucosal inflammation with evidence of an enhanced Th1 environment.T.muris infection accelerated the progression of colitis in Mdr1a-/-as evidenced by marked increases in several indicators including histological damage score,mucosal CD4+T-cell and DC infiltration and dramatically increased production of proinflammatory cytokines.CONCLUSION:These data provide further evidence of the complex interaction between T.muris and an inflammatory bowel disease(IBD)-susceptible host which may have relevance to the application of helminth therapy in the treatment of human IBD.

Regulation of the cell fate by DNA damage and hypoxia

In order to provide the means for the design of novel rational anti-cancer drug therapies research efforts are concentrated on unravelling the molecular circuits which induce programmed cell death and block proliferation of cancer cells.Modern therapeutic strategies are based on the understanding of the complexity of physiological functions such as differentiation,development,immune responses,cell-cycle arrest,DNA damage repair,apoptosis,autophagy,energy metabolism,and senescence.It has become evident that this knowledge will provide the means to target the components of the pathways involved in these processes in a specific and selective manner thus paving the way for the development of effective and personalised anti-cancer therapies.Transcription is a crucial cellular process that regulates a multitude of physiological functions,which are essential in disease progression and cellular response to therapy.Transcription factors such as the p53 tumor suppressor and the hypoxia-inducible factor-α(HIF-α) are key players in carcinogenesis and cellular response to cancer therapies.Both of these transcription factors regulate gene expression of genes involved in cell death and proliferation,in some cases cooperating towards producing the same outcome and in some others mediating opposing effects.It is thus apparent that fine tuning of the activity of these transcription factors is essential to determine the cellular response to therapeutic regimens,in other words whether tumor cells will commit to apoptosis or evade engagement with the anti-proliferative effects of drugs leading to drug resistance.Our observations support the notion that the functional crosstalk between HIF-1α and p53 pathways and thus the fine tuning of their transcriptional activity is mediated by cofactors shared between the two transcription factors such as components of the p300 co-activator multiprotein complex.In particular,there is evidence to suggest that differential composition of the co-modulatory protein complexes associated with p53 and HIF-la under diverse types of stress conditions differentially regulate the expression of distinct subsets of p53 and HIF-la target genes involved in processes such as cell cycle arrest,apoptosis,chronic inflammation,and cellular energy metabolism thereby determining the cellular fate under particular types of microenvironmental stress.

Growth retrieval of stressed bacterial cells: logic and contradictions

Study of bacterial stress response against an array of stress signals like heat shock and oxidative stress has been well accomplished so far.Several stress factors cause microorganisms to go under the viable but nonculturable state.However,the growth resuscitation of bacterial cells from such viable but nonculturable state is still obscure.Current review briefly focused on the growth revival of the viable but nonculturable cells and placed the possible model of growth resuscitation.The significance of such type of study on the viable but nonculturable cells principally relies upon clinical sectors whereby some pathogens are found to be latent for many days and thereby imparting the false negative results as well as in the food industries whereby the viable but nonculturable cells may cause massive damage in the public health upon their resuscitation.

Pathogenesis of the Chikungunya virus and the host immunity response

Along with the running COVID-19 pandemic by the severe acute respiratory syndrome coronavirus 2,the Chikungunya virus is already known as the causative agent of re-emerging Chikungunya fever in many countries after several years of latency;and it’s certainly one of the most important clinical issues possibly due to the lack of appropriate vaccination.Therefore,continuous study and monitoring of this disease outbreak demand attention by the relevant health professionals.Present review has been written in the light of the recently available reports on the Chikungunya virus infection.The genomic structure and its impact on the viral epidemiology,the possible protective immunity,and the infection mitigation strategies have been discussed.It’s already well known that the Chikungunya virus can start infection after getting entrance into the blood circulation through the mosquito bites followed by the dissemination into the major organs like liver,brain,eye,joints and lymph nodes in order to inaugurate the infectivity.Apparently,the occurrence of death is very rare but the extreme fatality and morbidity may occur if the patient has other underlying disease conditions.The molecular aspects of the virus,the site-specific damages caused by the viral infection,and finally,the public awareness of such viral infection as discussed in the current review would help to maintain the public health sustainability especially in the developing countries whereby the knowledge on the required hygiene is poor.

包虫病手术患者1312例流行病学资料分析

目的了解青藏高原包虫病的分布特点。方法对1992-2006年的1312例包虫病手术患者的相关资料进行分析。结果囊型和泡型包虫病均有分布。患者主要集中于21～50岁,20岁以下的患者相对较少,以藏族为主。囊型包虫病分布于四川省甘孜州和阿坝州的17个县以及青海省果洛州的5个县,而泡型包虫病同时分布于其中的大部分地区。结论囊型和泡型包虫病同时流行于四川省的西北部和青海省的东南部。

四川省雅江县藏区人群绦/囊尾蚴病流行现状

目的了解四川省雅江县呷拉乡藏族人群绦虫病/囊尾蚴病流行现状。方法通过问卷、体检了解近一年内人群排绦虫史、癫痫发作史、皮下结节以及相关的其他临床表现。对自愿接受治疗的患者用吡喹酮驱除绦虫,用multiplex PCR对虫种进行鉴定。对1例高度怀疑为猪带绦虫患者的粪便标本采用粪-PCR进行检测。用囊液抗原检测血清囊尾蚴病特异性抗体,了解人群囊尾蚴感染水平。结果11.96%(216/1806)的村民近一年内有排绦虫史,1.05%(19/1806)发现皮下结节,0.61%(11/1806)有癫痫发作史。24份虫体标本PCR鉴定结果均为牛带绦虫,1份粪便标本粪-PCR结果为猪带绦虫。4.35%(4/92)人群血清囊尾蚴病抗体阳性。结论牛带绦虫和猪带绦虫共同流行于雅江县呷拉乡,以牛带绦虫为优势虫种。人群囊尾蚴感染率为4.35%。

Grass height and transmission ecology of Echinococcus multilocularis in Tibetan communities, China

Background Alveolar echinococcosis is a major zoonosis of public health significance in western China. Overgrazing was recently assumed as a potential risk factor for transmission of alveolar echinococcosis. The research was designed to further test the overgrazing hypothesis by investigating how overgrazing influenced the burrow density of intermediate host small mammals and how the burrow density of small mammals was associated with dog Echinococcus multilocularis infection. Methods The study sites were chosen by previous studies which found areas where the alveolar echinococcosis was prevalent. The data, including grass height, burrow density of intermediate host small mammals, dog and fox fecal samples as well as Global Positioning System （GPS） position, were collected from field investigations in Shiqu County, Sichuan Province, China. The fecal samples were analyzed using copro-PCR. The worms, teeth, bones and hairs in the fecal samples were visually examined. Single factor and multifactor analyses tools including chi square and generalized linear models were applied to these data. Results By using grass height as a proxy of grazing grass in the pasture led to lower small mammals＇ pressure in the homogenous pasture, this study found that taller burrow density （X2=4.670, P=0.031, coefficient=-1.570）. The Echinococcus multilocularis worm burden in dogs was statistically significantly related to the maximum density of the intermediate host Ochotona spp. （X2=5.250, P=-0.022, coefficient=0.028）. The prevalence in owned dogs was positively correlated to the number of stray dogs seen within a 200 meter radius （Wald X2=8.375, P=-0.004, odds ratio=1.198）. Conclusions Our findings support the hypothesis that overgrazing promotes transmission of alveolar echinococcosis and confirm the role of stray dogs in the transmission of alveolar echinococcosis.

Seasonal pattern of Echinococcus re-infection in owned dogs in Tibetan communities of Sichuan, China and its implications for control

Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source of human infection,and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.:both domestic livestock(CE)viscera and small mammals(AE),in early winter and again in spring.We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp.in these two seasons and conducted a reinfection study to investigate this further.Methods:Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture(Sichuan Province,China),and Echinococcus spp.infection status was determined using copro-antigen ELISA.Dogs were sampled in April(spring),July(early summer),September/October(autumn/early winter)and December(winter)in 2009;and in April(spring)2010.Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms.Information on dog sex,age and body weight was also collected.The t-test,Fisher’s exact test,Poisson regression and logistic regression were used to compare means and prevalences,and to identify factors associated with infection status.Results:The proportion of female dogs was significantly lower than that of male dogs;female dogs had significantly higher(22.78%)baseline copro-ELISA prevalence than males(11.88%).Dog body weight,sex,age,county and previous infection status at any sampling point had no influence on the re-infection prevalence in general.Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans.Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009,suggesting a higher infection pressure in these seasons comparing with other seasons.Conclusion:Following praziquantel treatment,dog body weight,sex,age,county,deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general.The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp.infection pressure in the region.Early winter,spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.

Priorities for research and control of cestode zoonoses in Asia

Globally,cestode zoonoses cause serious public health problems,particularly in Asia.Among all neglected zoonotic diseases,cestode zoonoses account for over 75%of global disability adjusted life years(DALYs)lost.An international symposium on cestode zoonoses research and control was held in Shanghai,China between 28th and 30th October 2012 in order to establish joint efforts to study and research effective approaches to control these zoonoses.It brought together 96 scientists from the Asian region and beyond to exchange ideas,report on progress,make a gap analysis,and distill prioritizing settings with a focus on the Asian region.Key objectives of this international symposium were to agree on solutions to accelerate progress towards decreasing transmission,and human mortality and morbidity caused by the three major cestode zoonoses(cystic echinococcosis,alveolar echinococcosis,and cysticercosis);to critically assess the potential to control these diseases;to establish a research and validation agenda on existing and new approaches;and to report on novel tools for the study and control of cestode zoonoses.

中国中部寄生虫病的景观控制(英文)

多房棘球绦虫(Echinococcus multilocularis)的幼虫期导致罕见而致命的肝病即人类的泡型包虫病(HAE)。绦虫在狐狸(或狗类)与一些小型哺乳类动物之间以寄生虫-寄主的方式进行循环传播。中国中部一些地区的人类泡型包虫病属于地方流行病,在部分乡村的发生概率达到15%。本文研究如何利用遥感数据并基于地区景观特性获取该流行病清晰地空间危害分布图。遥感数据分析的结果显示,人类居住地附近的草地或灌木是HAE传播的一个主要危险区域,从空间分布上看,这些区域是小型哺乳动物等中间寄主的聚集处。

Oxidative stress and breast cancer biomarkers:the case of the cytochrome P450 2E1

Aim:The aim of the study is to investigate the impact of the cytochrome P4502E1,which is the most efficient CYP450 family member in generating reactive oxygen species(ROS),on cellular energy metabolism of breast cancer cells and therefore the effects of CYP2E1 on breast carcinogenesis.Methods:The estrogen receptor positive MCF-7 and the triple negative MDA-MB-231 breast cancer cells were used as experimental system to estimate ROS generation in these cells overexpressing CYP2E1 and treated with the glycolytic inhibitors 3-bromopyruvate or 2-deoxyglucose in the presence or absence of the CYP2E1 inhibitor chlormethiazole.Adenosine triphosphate(ATP)assay was used to measure ATP production and lactate assay to quantify the efflux of lactic acid in breast cancer cells treated with the CYP2E1 inhibitor chlormethiazole,the mitochondrial membrane potential and cell viability assays were employed to assess the pathway of cellular energy production and cellular death respectively after treatment of MCF-7 and MDA-MB-231 with the CYP2E1 activator acetaminophen or the CYP2E1 inhibitor chlormethiazole.Results:T he r esults i ndicated i ncreased ROS generation i n b reast c ancer c ells overexpressing C YP2E1.ROS generation was differentially regulated in breast cancer cells upon treatment with the CYP2E1 inhibitor chlormethiazole.Chlormethiazole treated MCF-7 cells exhibited reduced lactate efflux implying that CYP2E1 directly or indirectly regulates the glycolytic rate in these cells.Furthermore the mitochondrial membrane potential of both MCF-7 and MDA-MB-231 cells was differentially affected by the CYP2E1 activator acetaminophen versus the CYP2E1 inhibitor chlormethiazole providing additional support for the involvement of CYP2E1 in energy metabolic pathways in breast cancer.Conclusion:Results presented in this study provide evidence to suggest that CYP2E1 regulates cellular energy metabolism of breast cancer cells in a manner dependent on cell type and potentially on the clinical staging of the disease therefore CYP2E1 is a possible breast cancer biomarker.

Impact of overgrazing on the transmission of Echinococcus multilocularis in Tibetan pastoral communities of Sichuan Province,China

Background Overgrazing was assumed to increase the population density of small mammals that are the intermediate hosts of Echinococcus multilocularis, the pathogen of alveolar echinococcosis in the Qinghai Tibet Plateau. This research tested the hypothesis that overgrazing might promote Echinococcus multilocularis transmission through increasing populations of small mammal, intermediate hosts in Tibetan pastoral communities. Methods Grazing practices, small mammal indices and dog Echinococcus multilocularis infection data were collected to analyze the relation between overgrazing and Echinococcus multilocularis transmission using nonparametric tests and multiple stepwise logistic regression. Results In the investigated area, raising livestock was a key industry. The communal pastures existed and the available forage was deficient for grazing. Open （common） pastures were overgrazed and had higher burrow density of small mammals compared with neighboring fenced （private） pastures; this high overgrazing pressure on the open pastures measured by neighboring fenced area led to higher burrow density of small mammals in open pastures. The median burrow density of small mammals in open pastures was independently associated with nearby canine Echinococcus multilocularis infection （P=-0.003, OR=1.048）. Conclusion Overgrazing may promote the transmission of Echinococcus multilocularis through increasing the population density of small mammals.

Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options

Objective: Echinococcosis is a major parasitic zoonosis of public health importance in western China. In 2004, the Chinese Ministry of Health estimated that 380,000 people had the disease in the region. The Qinghai-Tibet Plateau is highly co-endemic with both alveolar echinococcosis (AE) and cystic echinococcosis (CE). In the past years, the Chinese government has been increasing the financial support to control the diseases in this region. Therefore, it is very important to identify the significant risk factors of the diseases by reviewing studies done in the region in the past decade to help policymakers design appropriate control strategies. Review: Selection criteria for which literature to review were firstly defined. Medline, CNKI (China National Knowledge Infrastructure), and Google Scholar were systematically searched for literature published between January 2000 and July 2011. Significant risk factors found by single factor and/or multiple factors analysis were listed, counted, and summarized. Literature was examined to check the comparability of the data;age and sex specific prevalence with same data structures were merged and used for further analysis. A variety of assumed social, economical, behavioral, and ecological risk factors were studied on the Plateau. Those most at risk were Tibetan herdsmen, the old and female in particular. By analyzing merged comparable data, it was found that females had a significant higher prevalence, and a positive linearity relationship existed between echinococcosis prevalence and increasing age. In terms of behavioral risk factors, playing with dogs was mostly correlated with CE and/or AE prevalence. In terms of hygiene, employing ground water as the drinking water source was significantly correlated with CE and AE prevalence. For definitive hosts, dog related factors were most frequently identified with prevalence of CE or/and AE;fox was a potential risk factor for AE prevalence only. Overgrazing and deforestation were significant for AE prevalence only. Conclusion: Tibetan herdsmen communities were at the highest risk of echinococcosis prevalence and should be the focus of echinococcosis control. Deworming both owned and stray dogs should be a major measure for controlling echinococcosis;treatment of wild definitive hosts should also be considered for AE endemic areas. Health education activities should be in concert with the local people's education backgrounds and languages in order to be able to improve behaviors. Further researches are needed to clarify the importance of wild hosts for AE/CE prevalence, the extent and range of the impacts of ecologic changes (overgrazing and deforestation) on the AE prevalence, and risk factors in Tibet.

Spectral characteristics of plant communities from salt marshes:A case study from Chongming Dongtan,Yangtze estuary,China

The spectral reflectance of recently formed salt marshes at the mouth of the Yangtze River,which are undergoing invasion by Spartina alterniflora,were assessed to determine the potential utility of remotely sensed data in assessing future invasion and changes in species composition.Following a review of published research on remote sensing of salt marshes,53 locations along three transects were sampled for paired data on plant species composition and spectral reflectance using a FieldSpecTM Pro JR Field Portable Spectroradiometer.Spectral data were processed concerning reflectance,and the averaged reflectance values for each sample were reanalysed to correspond to a 12-waveband bandset of the Compact Airborne Spectral Imager.The spectral data were summarised using principal components analysis(PCA)and the relationships between the vegetation composition,and the PCA axes of spectral data were examined.The first PCA axis of the reflectance data showed a strong correlation with variability in near infrared reflectance and‘brightness’,while the second axis was correlated with visible reflectance and‘greenness’.Total vegetation cover,vegetation height,and mudflat cover were all significantly related to the first axis.The implications of this in terms of the ability of remote sensing to distinguish the various salt marsh species and in particular the invasive species S.alterniflora were discussed.Major differences in species with various physiognomies could be recognised but problems occurred in separating early colonising S.alterniflora from other species at that stage.Further work using multi-seasonal hyperspectral data might assist in solving these problems.

STOP1 regulatory system: Centered on multiple stress tolerance and cellular nutrientmanagement

Transcriptional regulation plays a crucial role in plant adaptation to diverse environments.Several transcription factors(TFs),the so-called master switch TFs or hub TFs,regulate various genes critical for adaptation to different stresses.STOP1(SENSITIVE TO PROTON RHIZOTOXICITY 1),a zinc-finger TF of Arabidopsis(Arabidopsis thaliana),is one such master/hub TF that transcriptionally regulates multiple stress tolerance(Sadhukhan et al.,2021).STOP1 plays a critical role in tolerance to acid soil syndrome(i.e.,H+and Al3+tolerance)(Iuchi et al.,2007)and hypoxia tolerance(Enomoto et al.,2019),and negatively regulates drought tolerance(Sadhukhan et al.,2019).In addition,Tian et al.