The factors of biological indicator resistance

Biological indicator(BI)is the gold standard in verifying the effectiveness of the sterilization processes.The resistance of biological indicators generally means the population of viable organism and D value.The population and the D value are all not intrinsic,which will vary according to the lot,the manufacturer.Spores,carrier,recovery medium and the packaging compose the self-contained biological indicators.And all of the component will affect BI resistance.Different kinds of carrier spore inoculated on exhibit different manners to attach different D-values.Another factor that affects the resistance of BI is spore production methods.The sporulation conditions including temperature,p H,humidity,nutrient and ions content,largely influence the spore resistance to heat.Furthermore,resistometer performance and the different test method are also the major source of the D value variation.All the factors affect the resistance of biological in an comprehensive manner,and when a resistance variation occur,all the factors above should be taken into consideration.

A review of soil nematodes as biological indicators for the assessment of soil health

Healthy soils are essential for sustainableagricultural development and soil health requires carefulassessment with increasing societal concern over envir-onmentally friendly agricultural development. Soil healthis the capacity of soil to function within ecologicalboundaries to sustain productivity, maintain environmentalquality, and promote plant and animal health. Physical,chemical and biological indicators are used to evaluate soilhealth;the biological indicators include microbes, proto-zoa and metazoa. Nematodes are the most abundantmetazoa and they vary in their sensitivity to pollutants andenvironmental disturbance. Soil nematode communitiesare useful biological indicators of soil health, withcommunity characteristics such as abundance, diversity,community structure and metabolic footprint all closelycorrelated with the soil environment. The community size,complexity and structure reflect the condition of the soil.Both free-living and plant parasitic nematodes are effec-tive ecological indicators, contributing to nutrient cyclingand having important roles as primary, secondary andtertiary consumers in food webs. Tillage inversion,cropping patterns and nutrient management may havestrong effects on soil nematodes, with changes in soilnematode communities reflecting soil disturbance. Somefree-living nematodes serve as biological models to testsoil condition in the laboratory and because of theseadvantages soil nematodes are increasingly being used asbiological indicators of soil health.

Biological indicators of sub-optimal health status

OBJECTIVE:To investigate biological indicators of sub-optimal health status and provide means of objective assessment of sub-optimal health status.METHODS:We set the unified standards for diagnosing a SHS.We tested various laboratory indicators in 407 cases that we selected randomly from2807 subjects and collected 15 mL of fasting venous blood from each case.We measured serum immunoglobulin A(IgA)and immunoglobulin G(IgG)concentrations,serum beta endorphins(β-EP),cortisol(C),testosterone(T),plasma adrenocorticotropic hormone(ACTH)and serum T lymphocyte subsets CD3+and CD4+.RESULTS:Mean serum testosterone concentrations and their ratio to cortisol(C)concentrations weresignificantly higher in the healthy group than in those with sub-optimal health status(P<0.01).Mean serum CD3+concentrations were significantly higher in those with sub-optimal health status than in the healthy group(P<0.05).CONCLUSION:Decreased serum testosterone/cortisol ratio may be an objective indication of sub-optimal health status.Changes in neuroendocrine and immunological indicators may explain some of the symptoms,including malaise and poor work performance,attributable to persistent or relapsing fatigue in subjects with sub-optimal health status.

Establishment of injury models in studies of biological effects induced by microwave radiation

Microwave radiation has been widely used in various fields,such as communication,industry,medical treatment,and military applications.Microwave radiation may cause injuries to both the structures and functions of various organs,such as the brain,heart,reproductive organs,and endocrine organs,which endanger human health.Therefore,it is both theoretically and clinically important to conduct studies on the biological effects induced by microwave radiation.The successful establishment of injury models is of great importance to the reliability and reproducibility of these studies.In this article,we review the microwave exposure conditions,subjects used to establish injury models,the methods used for the assessment of the injuries,and the indicators implemented to evaluate the success of injury model establishment in studies on biological effects induced by microwave radiation.

Novel soil quality indicators for the evaluation of agricultural management practices:a biological perspective

Developments in soil biology and in methodsto characterize soil organic carbon can potentially delivernovel soil quality indicators that can help identifymanagement practices able to sustain soil productivityand environmental resilience. This work aimed atsynthesizing results regarding the suitability of a range ofsoil biological and biochemical properties as novel soilquality indicators for agricultural management. The soilproperties, selected through a published literature review,comprised different labile organic carbon fractions [hydrophilicdissolved organic carbon, dissolved organic carbon,permanganate oxidizable carbon (POXC), hot waterextractable carbon and particulate organic matter carbon],soil disease suppressiveness measured using a Pythium-Lepidium bioassay, nematode communities characterizedby amplicon sequencing and qPCR, and microbialcommunity level physiological profiling measured withMicroResp™. Prior studies tested the sensitivity of each ofthe novel indicators to tillage and organic matter additionin ten European long-term field experiments (LTEs) andassessed their relationships with pre-existing soil qualityindicators of soil functioning. Here, the results of theseprevious studies are brought together and interpretedrelative to each other and to the broader body of literatureon soil quality assessment. Reduced tillage increasedcarbon availability, disease suppressiveness, nematoderichness and diversity, the stability and maturity of thefood web, and microbial activity and functional diversity.Organic matter addition played a weaker role in enhancingsoil quality, possibly due to the range of composition of theorganic matter inputs used in the LTEs. POXC was theindicator that discriminated best between soil managementpractices, followed by nematode indices based on functionalcharacteristics. Structural equation modeling showsthat POXC has a central role in nutrient retention/supply,carbon sequestration, biodiversity conservation, erosion control and disease regulation/suppression. The novelindicators proposed here have great potential to improveexisting soil quality assessment schemes. Their feasibilityof application is discussed and needs for future research are outlined.

Estimating total nitrogen deposition in agroecosystems in northern China during the wheat cropping season

Atmospheric nitrogen (N) deposition has been poorly documented in northern China, an intensive agricultural and industrial region with large emissions of NHx and NOy. To quantify N deposition, total airborne N deposition was determined at three agricultural sites using a manual integrated total nitrogen input (ITNI) system during growth of winter wheat (Triticum aestivum L.) and Italian ryegrass (Lolium multiflorum Lam.) from September 2005 to May 2006. Total estimated N deposition averaged 54.9 and 43.2 kg N/hm2 across the three sites when wheat was grown to flowering and maturing, respectively. The average value was 50.2 kg N/hm2 when ryegrass was the indicator plant. Both indicator species gave similar total airborne N input results. The intermediate level of N supplied resulted in the highest N deposition, and the ratio of N acquired from deposition to total N content of the whole system decreased with increasing N supply to the roots. The contribution of atmospheric N to the total N content of the wheat and ryegrass sand culture systems ranged from 10% to 24%.

Eukaryotic microbial distribution pattern and its potential effects on fisheries in the fish reserves of Qiantang River in breeding season

To examine the eukaryotic biodiversity of aquatic ecosystems in the Qiantang River,China,eukaryotic microbes in the river were investigated using 18S rRNA gene sequencing during the breeding season(July to August 2018).Four distinct distribution patterns(1.Jiande;2.Tonglu and Fuyang;3.Jiubao;4.Yanguan)of the microbial community and their potential effects on fishery activities were observed.Results show lower abundances of Dinophyta and Fungi and higher abundances of Cryptophyta and Chlorophyta in Tonglu and Fuyang than those in the other three sections.In addition,the reserves(Tonglu and Fuyang)destabilized the original eukaryotic microbial co-occurrence network.Among all the environmental factors measured,nitrogen(nitrite,nitrate,ammonium),water temperature and total chlorophyll a acted as major driving factors that controlled the eukaryotic microbial distribution.Furthermore,the existence of some algae(e.g.,Chrysophyceae,Cryptophytes,and Chlorophyceae)and fungi(e.g.,Rhizophydium)in Tonglu and Fuyang was beneficial to juvenile fish growth and water quality,although some detrimental species(e.g.,Aphanomyces)needed attention.This study provides further insights into the sustainable protection and utilization of rivers.

Responses of acrocarpous moss communities to heavy metal(Fe,Mn,Cd)and sulfur pollution in the Changgou carbonate manganese ore,SW China

Bryophyte communities have been widely used to monitor and assess heavy metal pollution in soil,air and water.However,the unique value of acrocarpous moss in monitoring environmental pollution and the harm of non-metallic sulfur to human health caused by carbonate manganese mining were seldom considered in previous studies.This study investigated the heavy metal and sulfur pollution level by soil and moss sample collection in Changgou manganese ore and its surrounding environment in the Zunyi area,Guizhou Province,China.By means of cluster analysis,diversity analysis,correlation analysis and redundancy analysis,the relationship between dominant moss communities and major pollutants were analyzed.The results showed that there were pollutants such as iron(Fe),manganese(Mn),cadmium(Cd),sulfur(S)and others in the 500 meters buffer zone centered on Changgou manganese ore.The ore sorting area and waste rock accumulation area were considered as the most seriously polluted,followed by the ore outlet area and ore transport line,at last the miners’living area and vegetable planting area were the least polluted.A total of 23 species of moss communities were identified in the Changgou manganese ore area,among which 9 were dominant,including Bryum blindii Bruch&Schimp.(Bry.bli),Weissia planifolia Dix(Wei.pla)-Bry.bli,Bryum caespiticium Hedw.(Bry.cae),Bryum pallescens Schleicher ex Schw?gr.(Bry.pal),Didymodon longicostatus X.J.Li et Iwats(Did.lon),Weissia brachycarpa(Nees&Hornsch.)Jur.(Wei.bra),Trichostomum brachydontium Bruch.(Tri.bra),Bryum argenteum Hedw.(Bry.arg)Wei.bra and Bryum algovicum Sendt.ex M?ll.Hal.(Bry.alg),all of which are from the acrocarp species.Bry.cae showed a strong tolerance to S,Did.lon to Fe,Bry.pal to Cd and Bry.bli to Mn.There was a significant correlation between the main polluting elements and the dominant bryophyte community(P<0.05),indicating a high biological indicator value.Together,our results can provide the scientific basis for soil pollution monitoring and human health risk assessment in carbonate manganese mining areas.

The substance composition of sterols in the sediments from the Chukchi Sea,the Bering Sea and global climatic significance

The compounds of sterols such as C27 ,C2s ,C29 and C30 are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5,22 as well as 22-,24-. The compound of sterols such as C27 ,C28 ,C29 are recorded from B2-9 core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments （2 -0 era）in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco - environmental change responding to climatic effect of circumjacent.

Human activity over natural inputs determines the bacterial community in an ice core from the Muztag ata glacier

Ice core provides a valuable vertical timeline of past climates and anthropogenic activities.Environmental proxies have been widely used in these studies,but there are few biological indicators available.To address this gap,we investigated the bacterial community from a 74 m ice core of Muztag ata glacier on the Tibetan Plateau to link biological indicators with past climate and anthropogenic activities.By analyzing the portion of the ice core with environmental proxies available(corresponding to 1907 to 1991),we observed an increase in bacterial richness throughout the ice core,which was associated with higher NH_(4)^(+),an indicator of agricultural development.The bacterial community was jointly determined by human activity,natural input,and air temperature,with a strong human influence after the 1950s.Furthermore,the relative abundance of animal gut-associated bacteria,including Aerococcaceae,Nocardiaceae,Muribaculaceae,and Lachnospiraceae,was associated with livestock number changes in the Central Asian region.Together with other bacterial lineages,they jointly explained 59.8%of the livestock number changes.This study provides quantitative evidence of the associations between bacterial indicators and past climate and human activities,highlighting the potential of using bacterial proxies for ice core studies.

Assessment of the ecological state of haplic chernozem contaminated by oil,fuel oil and gasoline after remediation

The intensive use of petroleum hydrocarbon products has made them priority environmental pollutants.When petroleum hydrocarbons enter the soil,a change in physical,chemical,and biological properties is observed.The natural restoration of oil-contaminated soils is a lengthy process;therefore,remediation is often required.The aim of this study is to assess the change in the ecological state of haplic chernozem soil contaminated with oil,fuel oil,and gasoline after remediation.The indicators of soil biological activity,such as phytotoxicity(germination,length of shoots and roots),the activity of oxidoreductase enzymes(catalase and dehydrogenases),and the total number of bacteria were studied.The effects of nitroammophoska fertilizer,sodium humate,biochar,and the biofertilizer“Baikal EM-1”on the ecological state of soils contaminated with oil,fuel oil,and gasoline were studied.Pollution with oil,fuel oil,and gasoline decreased the values of all biological indicators.The most sensitive indicator was the length of radish roots in soils polluted with oil,gasoline,and fuel oil after remediation with nitroammophoska and Baikal EM-1 addition.The length of roots was the most sensitive indicator when remediation was performed with biochar and sodium humate added to soil contaminated with oil and gasoline,and with contamination of haplic chernozem soil with fuel oil,the total number of bacteria was the most sensitive indicator.The most effective ameliorant to phytotoxicity indicators for oil pollution was a 1 D dose of biochar,for fuel oil it was 1 D biochar and 2 D sodium humate,and for gasoline it was a 2 D dose of biochar and Baikal EM-1.All ameliorants at most of the studied doses increased dehydrogenase activity,but increased catalase activity only in some cases.An increase in the total number of bacteria in oil-contaminated soils was promoted by biochar and nitroammophoska at a dose of 2 D.Nitroammophoska was the most effective in ameliorant in soils contaminated with fuel oil;in soils polluted with gasoline,all doses of ameliorant increased the number of bacteria equally.The stimulating effect of ameliorants on biological activity of oil-contaminated haplic chernozem were in the following sequence:nitroammophoska>biochar>sodium humate>Baikal EM-1.The 2 D biochar dose was most effective.The stimulation of biological indicators by ameliorants when soil was contaminated with fuel oil were in the following sequence:biochar>Baikal EM-1>sodium humate>nitroammophoska.The same sequence of ameliorant stimulation was observed in soil polluted with gasoline.The results of this study can be used to biodiagnose the ecological state of oil-contaminated soils after remediation.

Evaluation methods of heavy metal pollution in soils based on enzyme activities:A review

Soil enzyme activities have been suggested as suitable indicators for the evaluation of metal contamination because they are susceptible to microbial changes caused by heavy metal stress and are strictly related to soil nutrient cycles.However,there is a growing lack of recognition and summary of the historic advancements that use soil enzymology as the proposal of evaluation methods.Here,we review the most common methods of heavy metal pollution evaluation based on enzyme activities,which include single enzyme index,combined enzyme index,enzyme-based functional diversity index,microbiological stress index,and ecoenzymatic stoichiometry models.This review critically examines the advantages and disadvantages of these methods based on their execution complexity,performance,and ecological implications and gets a glimpse of avenues to come to improved future evaluation systems.Indices based on a single enzyme are variable and have no consistent response to soil heavy metals,and the following three composite indices are characterized by the loss of many critical microbial processes,which thus not conducive to reflect the effects of heavy metals on soil ecosystems.Considering the dexterity of ecoenzymatic stoichiometry methods in reflecting changes in soil functions under heavy metal stress,we propose that microbial metabolic limitations quantified by ecoenzymatic stoichiometry models could be promising indicators for enhancing the reality and acceptance of results and further improving the potential for actual utility in environmental decision-making.

Influence of peach(Prunus persica Batsch)phenological stage on the short-term changes in oxidizable and labile pools of soil organic carbon and activities of carbon-cycle enzymes in the North-Western Himalayas

The labile organic carbon(C)and C-related enzymes are sensitive indicators capturing alterations of soil organic matter(SOM),even in a short-time scale.Although the effects of crop husbandry and land use change on these attributes have been well studied,there is no consensus about how plant phenology may impact them.This study aimed to determine the short-term effect o f six distinct phenological stages(PS-1:full bloom;PS-2:fruit set;PS-3:pit hardening;PS-4:physiological maturity;PS-5:60 d after physiological maturity;and PS-6:fall)o f peach on the changes in soil organic carbon(SOC)fractions of different oxidizability,labile C pools,and C-cycle enzyme activities in soils,for two consecutive years(2015 and 2016)in the North-Western Himalayas(NWH).Peach rhizosphere soils were sampled at the topsoil(0-15 cm)and subsoil(16-30 cm)layers,along with rhizosphere soils from adjacent perennial grasses,which served as a control.Values for most of the assessed parameters,including very labile C,labile C,microbial biomass C,permanganate oxidizable C,dissolved organic C,mineralizable C,amylase activity,and carboxymethyl-cellulase activity,were significantly(P<0.05)higher at PS-3 than at other phenological stages of peach.Conversely,a sudden decline in these soil variables was recorded at PS-5,followed by a slight buildup at PS-6,particularly in the topsoil of the peach orchard.Short-term changes in organic C fractions of different oxidizability,influenced by peach phenological stage,significantly(P<0.05)affected C management index,C pool index,and lability index.Both the C management index and lability index showed their highest values at PS-3 and their lowest values at PS-5,clearly indicating short-term accretion and depletion of SOC,in tandem with the peach phenological events.Principal component analysis suggested that a composite of soil indicators,including microbial biomass C,dissolved organic C,amylase,and invertase,could help detect short-term changes in SOC content.It is concluded that peach phenological events had a major impact on the short-term variations of the studied soil variables,which could be attributed to changes in the above-and belowground plant residues,as well as the extent of nutrients and water acquisition.

Study of cadmium(Cd)-induced oxidative stress in Eisenia fetida based on mathematical modelling

As a sensitive biological indicator,earthworms are widely used to monitor various pollutants of soil and provide an early warning for soil pollution.However,because many indices are involved in the exposure-induced oxidative stress response,practical applications of these indices are quite inconvenient.Therefore,it is appropriate to investigate the key monitoring index for use in early warning and pollution monitoring.Using Eisenia fetida as an experimental model in an indoor simulation experiment,the mathematical modelling of the effect on oxidative stress in earthworms under cadmium(Cd)stress was studied.The test lasted 40 d,with the removal of one earthworm every 10 d.The Cd2+concentration gradient was set as 0,1,10,20,100,200,400,and 800 mg kg^(-1) dry weight.The earthworms were divided into two sections from the clitellum for the determination of total protein(TP)and peroxidase(POD),superoxide dismutase(SOD),glutathione-S-transferase(GST),glutathione peroxidase(GPX),catalase(CAT),malondialdehyde(MDA),and acetylcholinesterase(AChE)activities.Results showed that POD was the key index of oxidative stress in head tissues after 10 d of exposure,TP was the key index at 20 d,and POD became the key index again at 30 and 40 d.By contrast,in tail tissues,MDA and SOD were the key indices at an exposure time of 10 d,GPX at 20 d,CAT and TP at 30 d,and POD and MDA at 40 d.These results contribute to establishing a scientific method for ecotoxicological diagnosis and revealing the mechanism of soil Cd toxicity.

Proteomic response of wheat embryos to fosthiazate stress in a protected vegetable soil

A proteomic analysis of wheat defense response induced by the widely used organophosphorus nematicide fosthiazate is reported. Seed germination and two-dimensional gel electrophoresis （2-DE） experiments were performed using a Chinese wheat cultivar, Zhenmai No. 5. Root and shoot elongation decreased but thiobarbituric acid reactive substances （TBARS） content in embryos increased with increasing pesticide concentration. More than 1000 protein spots were reprodueibly detected in each silver-stained gel. Thirty-seven protein spots with at least 2-fold changes were identified using MALDI-TOF MS/MS analysis. Of these, 24 spots were up-regulated and 13 were down-regulated. Proteins identified included some well-known classical stress responsive proteins under abiotic or biotic stresses as well as some unusual responsive proteins. Ten responsive proteins were reported for the first time at the proteomic level, including fatty acyl CoA reductase, dihydrodipicolinate synthase, DEAD-box ATPase-RNA-helicase, fimbriata-like protein, waxy B 1, rust resistance kinase Lrl0, putative In2.1 protein, retinoblastoma-related protein 1, pollen allergen-like protein and S-adenosyl-L- methionine：phosphoethanolamine N-methyltransferase. The proteins identified were involved in several processes such as metabolism, defense/detoxification, cell structure/ceU growth, signal transduction]transcription, photosynthesis and energy. Seven candidate proteins were further analyzed at the mRNA level by RT-PCR to compare transcript and protein accumulation patterns, revealing that not all the genes were correlated well with the protein level. Identification of these responsive proteins may provide new insight into the molecular basis of the fosthiazate-stress response in the early developmental stages of plants and may be useful in stress monitoring or stress-tolerant crop breeding for environmentally friendly agricultural production.

Lichens reveal the quality of indoor air in Selangor, Malaysia

Background:Indoor air quality(IAQ)is a concern in kindergartens as children spend much of their time there.Yet,there is a shortage of biological indicators needed for assessing IAQ.Thus,this study evaluated IAQ using transplanted lichen Usnea misaminensis as a biological indicator.Methods:Lichen samples,collected from Bukit Larut,Perak,Malaysia,were exposed to indoor and outdoor environments in an urban area(Ummi Aiman Kindergarten)and a rural area(Ummi Qaseh Pelangi Kindergarten)for 2 months during August 15 to October 14,2019.The concentrations of 12 selected elements and the vitality of the lichens were then evaluated.Results:Increased concentrations of eleven of the twelve elements deposited in the lichen samples in both urban and rural areas were observed.For both areas,the element concentrations in the samples from the indoor environment was lower than those from the outdoor environment,and those in the rural area were lower than those from in the urban area,suggesting the impacts of traffic emissions.The vitality of the lichens showed no significant change in indoor environment,compared to that in outdoor environment,indicating that even exposed to indoor environment,the lichens remained effective biological indicators as same as they were in the outdoor environment.Conclusions:Lichens are effective biological indicators for both outdoor and indoor environments.Furthermore,outdoor emissions could influence IAQ,which could be problematic in densely populated areas such as kindergartens.Mitigation measures should be taken.