Plasma B-esterase activities in European raptors

B-esterases are serine hydrolases composed of cholinesterases, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and carboxylesterase (CbE). These esterases, found in blood plasma, are inhibited by organophosphorus (OP) and carbamate (CB) insecticides and can be used as nondestructive biomarkers of exposure to anticholinesterase insecticides. Furthermore, B-esterases are involved in detoxification of these insecticides. In order to establish the level of these enzymes and to have reference values for their normal activities, total plasma cholinesterase (ChE), AChE and BChE activities, and plasma CbE activity were determined in 729 European raptors representing 20 species, four families, and two orders. The diurnal families of the Falconiforme order were represented by Accipitridae and Falconidae and the nocturnal families of the Strigiforme order by Tytonidae and Strigidae. Intraspecies differences in cholinesterase activities according to sex and/or age were investigated in buzzards (Buteo buteo), sparrowhawks (Accipiter nisus), kestrels (Falco tinnunculus), barn owls (Tyto alba), and tawny owls (Strix aluco). Sex-related differences affecting ChE and AChE activities were observed in young kestrels (2-3-mo-old) and age-related differences in kestrels (ChE and AChE), sparrowhawks (AChE), and tawny owls (ChE, AChE, and BChE). The interspecies analysis yielded a negative correlation between ChE activity and body mass taking into account the relative contribution of AChE and BChE to ChE activity, with the exception of the honey buzzard (Pernis apivorus). The lowest ChE activities were found in the two largest species, Bonelli's eagle (Hieraaetus fasciatus) and Egyptian vulture (Neophron percnopterus) belonging to the Accipitridae family. The highest ChE activities were found in the relatively small species belonging to the Tytonidae and Strigidae families and in honey buzzard of the Accipitridae family. Species of the Accipitridae, Tytonidae, and Strigidae families were characterized by a BChE contribution that dominated the total ChE activity, while in the species of the Falconidae family, AChE activity dominated. With the exception of the barn owl, CbE activity (eserine-insensitive alpha-naphthyl acetate esterase [alpha-NAE] activity) in all species was almost absent or very low. The values obtained in this study for ChE, AChE, and BChE activities and the AChE:BChE ratios for buzzard, kestrel, barn owl, and tawny owl provide a good estimate of the normal values in free-living individuals of these European species. They can be used as a baseline to evaluate the effect of anticholinesterase insecticides in the field.     

The relationships between brain, serum, and whole blood ChE activity in the wood mouse (Apodemus sylvaticus) and the common shrew (Sorex araneus) after acute sublethal exposure to dimethoate

Inhibition of cholinesterase (ChE) activity produced by a single acute intraperitoneal administration of dimethoate was studied in the wood mouse, Apodemus sylvaticus, and the common shrew, Sorex araneus, under laboratory conditions. ChE values from serum and whole blood were compared with those obtained from brain in order to obtain a non-destructive tool for predicting the severity of brain acetylcholinesterase (AChE) inhibition. In addition, serum and brain inhibition following oral exposure to dimethoate was also measured in the wood mouse. Normal ChE activity was higher in the brain and whole blood of the shrews than in wood mice. There was no difference between species in serum ChE activity. Exposure to dimethoate caused a dose-dependent reduction in ChE activity and there was a significant recovery in activity with increasing time after administration. In both species, serum and whole blood were more sensitive than brain for revealing organophosphate-induced ChE inhibition and serum was more sensitive than whole blood. Statistically significant relationships were defined between whole blood and brain ChE activity and between serum and brain ChE activity. Compared with serum, whole blood ChE activity was the more accurate predictor of brain AChE levels. The relationships between brain and serum ChE activity did not appear to be affected by the route of administration of the pesticide.     

The relationships between brain,serum, and whole blood ChE activity in the wood mouse (Apodemus sylvaticus) and the common shrew (Sorex araneus) after acute sublethal exposure to dimethoate

Abstract

Inhibition of cholinesterase (ChE) activity produced by a single acute intraperitoneal administration of dimethoate was studied in the wood mouse, Apodemus sylvaticus, and the common shrew, Sorex araneus, under laboratory conditions. ChE values from serum and whole blood were compared with those obtained from brain in order to obtain a non-destructive tool for predicting the severity of brain acetylcholinesterase (AChE) inhibition. In addition, serum and brain inhibition following oral exposure to dimethoate was also measured in the wood mouse. Normal ChE activity was higher in the brain and whole blood of the shrews than in wood mice. There was no difference between species in serum ChE activity. Exposure to dimethoate caused a dose-dependent reduction in ChE activity and there was a significant recovery in activity with increasing time after administration. In both species, serum and whole blood were more sensitive than brain for revealing organophosphate-induced ChE inhibition and serum was more sensitive than whole blood. Statistically significant relationships were defined between whole blood and brain ChE activity and between serum and brain ChE activity. Compared with serum, whole blood ChE activity was the more accurate predictor of brain AChE levels. The relationships between brain and serum ChE activity did not appear to be affected by the route of administration of the pesticide.     

Using dried blood spots stored on filter paper to measure cholinesterase activity in wild avian species.

Birds of prey that are poisoned by cholinesterase inhibitors (e.g. organophosphate and carbamate insecticides) are often cared for at animal shelters, rehabilitation centres and wildlife diagnostic facilities. Plasma cholinesterase (ChE) activity is a recognized method of assessing exposure to these insecticides, but standard blood-handling protocols are difficult to follow in non-laboratory settings. The primary objective of this study was to expand upon a method for storing human blood on filter paper without the need for complicated equipment or refrigeration, and to test its utility for measurement of ChE activity in avian blood. ChE activity from whole blood, plasma, and dried blood spots was analysed from 169 wild birds and comparisons made among sample types. ChE activity measured in whole blood haemolysates and dried blood spots were significantly correlated (r = 0.74, p < 0.001), as was ChE activity measured in plasma and dried blood spots (r = 0.68, p < 0.001). This study demonstrated that monitoring pesticide exposure in birds could be conducted using elementary blood sampling, preserving and shipping techniques.     

Characterization of cholinesterases in plasma of three Portuguese native bird species: application to biomonitoring

Over the last decades the inhibition of plasma cholinesterase (ChE) activity has been widely used as a biomarker to diagnose organophosphate and carbamate exposure. Plasma ChE activity is a useful and non-invasive method to monitor bird exposure to anticholinesterase compounds; nonetheless several studies had shown that the ChE form(s) present in avian plasma may vary greatly among species. In order to support further biomonitoring studies and provide reference data for wildlife risk-assessment, plasma cholinesterase of the northern gannet (Morus bassanus), the white stork (Ciconia ciconia) and the grey heron (Ardea cinerea) were characterized using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three ChE inhibitors (eserine sulphate, BW284C51, and iso-OMPA). Additionally, the range of ChE activity that may be considered as basal levels for non-exposed individuals was determined. The results suggest that in the plasma of the three species studied the main cholinesterase form present is butyrylcholinesterase (BChE). Plasma BChE activity in non-exposed individuals was 0.48±0.11 SD U/ml, 0.39±0.12 SD U/ml, 0.15±0.04 SD U/ml in the northern gannet, white stork and grey heron, respectively. These results are crucial for the further use of plasma BChE activity in these bird species as a contamination bioindicator of anti-cholinesterase agents in both wetland and marine environments. Our findings also underscore the importance of plasma ChE characterization before its use as a biomarker in biomonitoring studies with birds.     

Using dried blood spots stored on filter paper to measure cholinesterase activity in wild avian species

Birds of prey that are poisoned by cholinesterase inhibitors (e.g. organophosphate and carbamate insecticides) are often cared for at animal shelters, rehabilitation centres and wildlife diagnostic facilities. Plasma cholinesterase (ChE) activity is a recognized method of assessing exposure to these insecticides, but standard blood-handling protocols are difficult to follow in non-laboratory settings. The primary objective of this study was to expand upon a method for storing human blood on filter paper without the need for complicated equipment or refrigeration, and to test its utility for measurement of ChE activity in avian blood. ChE activity from whole blood, plasma, and dried blood spots was analysed from 169 wild birds and comparisons made among sample types. ChE activity measured in whole blood haemolysates and dried blood spots were significantly correlated (r=0.74, p<0.001), as was ChE activity measured in plasma and dried blood spots (r=0.68, p<0.001). This study demonstrated that monitoring pesticide exposure in birds could be conducted using elementary blood sampling, preserving and shipping techniques.     

Brain cholinesterase activity of nestling great egrets, snowy egrets and black-crowned night-herons

inhibition of brain cholinesterase (ChE) activity in birds is often used to diagnose exposure or death from organophosphorus or carbamate pesticides. Brain ChE activity in the young of altricial species increases with age; however, this relationship has only been demonstrated in the European starling (Sturnus vulgaris). Brain ChE activity of nestling great egrets (Casmerodius albus) collected from a colony in Texas (USA) increased significantly with age and did not differ among individuals from different nests. Brain ChE activity of nestling snowy egrets (Egretta thula) and black-crowned night-herons (Nycticorax nycticorax) collected in one colony each from Rhode Island, Texas and California (USA) also increased significantly with age and did not differ among individuals from different nests or colonies. This study further demonstrates that age must be considered when evaluating exposure of nestling altricial birds to ChE inhibitors.     

A survey of bryophytes for presence of cholinesterase activity

The neurotransmitter acetylcholine (ACh) is present in plants including bryophytes. The first biochemical evidence for ACh hydrolysis by enzyme cholinesterase (ChE) in bryophytes is presented. Thirty-nine species belonging to 16 families of bryophytes were surveyed for ChE activity. Thirty species belonging to 13 families showed ChE activity. Of the bryophytes tested, Anoectangium bicolor showed the highest ChE activity. Widespread distribution of ChE in bryophytes indicates their suitability as a system to study the role of ACh in plants.     

桂林两江国际机场内草坪动物与鸟类关系

2005年7月～2006年7月对桂林两江国际机场草坪动物及鸟类进行调查.共记录到鸟类9目23科48种,其中优势种是:田鹨、家燕、小云雀、棕背伯劳、黑卷尾、针尾沙锥、红隼、黑翅鸢;记录到昆虫13目76科,其中优势种有:直翅目、鞘翅目、双翅目、膜翅目、半翅目等昆虫和各种蜘蛛.鸟类数量和昆虫数量存在密切联系,鸟类数量峰值和昆虫数量峰值有部分重叠,说明昆虫数量对鸟类数量有影响.严格控制草坪昆虫数量能有效控制机场草坪的鸟类数量.蛙鼠类对草坪鸟类数量影响不大.     

鸟市贸易威胁野生鸟类生存——以哈尔滨道外花鸟鱼市场为例

为探讨鸟市贸易对野生鸟类的威胁与影响,给当地野生动物保护部门实施监管提供科学依据,于2016年11月—2017年11月对黑龙江省哈尔滨市最大鸟市——道外花鸟鱼市场进行调查。结果发现:(1)共记录6目34科83属117种18 729只鸟类,其中野生鸟类5目32科77属108种11 662只。有出售国家保护鸟种黄胸鹀 Emberiza aureola、猛禽及非法捕猎工具的现象。(2)所有被贩卖的野生鸟类中,在黑龙江省有分布的共69种,数量达9 707只。相关分析结果表明,黑龙江省有分布的野生鸟类是鸟市非法捕捉及贩卖的主要对象。(3)贩卖量为春、秋季多,夏、冬季少,7—10月鸟类迁徙季节时最多,占总贩卖量的45.2%,说明鸟类秋季迁徙是非法猎捕的高峰期。(4)调查中发现较多的南方鸟种(32.4%)也一定程度上说明野生鸟类非法运输的严重性。建议当地林业和草原局及时加强对道外花鸟鱼市场的监管,在鸟类迁徙季节从非法捕捉和运输环节实施严厉打击。     

Age-dependent changes in plasma and brain cholinesterase activities of house wrens and European starlings

We determined age-dependent changes in plasma and brain cholinesterase (ChE) activity for two species of passerines: house wren (Troglodytes aedon) and European starling (Sturnus vulgaris, starling). In plasma from nestlings of both species, total ChE activity increased with age, acetycholinesterase (AChE, EC 3.1.1.7) activity declined rapidly immediately after hatching, and butyrylcholinesterase (BChE, EC 3.1.1.8) activity increased steadily. For both species, total ChE and BChE activities and the BChE:AChE ratio in plasma were significantly greater in adults than nestlings suggesting trends observed in nestlings continue post fledging. In older nestlings and adults, AChE activity in plasma was significantly greater and BChE:AChE ratio less in house wrens than starlings. For house wrens as compared with starlings, ChE activity in brain increased at a significantly greater rate with age in nestlings and was significantly greater in adults. However, ChE activity in brain was similar at fledging for both species suggesting that the increase in ChE in brain is more directly related to ontogeny than chronologic age in nestlings of passerines. For both species, ChE activity increased significantly with brain weight of nestlings but not adults. House wrens hold similar patterns of age-dependent change in ChE activity in common with starlings but also exhibit differences in AChE activity in plasma that should be considered as a factor potentially affecting their relative toxicologic response to ChE inhibitors.     

Sex and storage affect cholinesterase activity in blood plasma of Japanese quail

Blood plasma cholinesterase (ChE) activity is a sensitive indicator of exposure to organophosphorus and carbamate insecticides. Effects of sex and storage of samples were studied as sources of variability by treating breeding Japanese quail (Coturnix japonica) with 3 mg of dicrotophos or carbofuran per kg of body weight and comparing blood plasma ChE activities for samples collected at 1 hr postdosage and assayed fresh, after 1 and 2 days of refrigeration (4 C), and after 1, 7 and 28 days of freezing (-25 C). ChE activity of fresh control plasma was 34% (P less than 0.01) higher in males than females. Male ChE activity remained essentially unchanged during storage while female ChE activity increased (P less than 0.05) gradually over time under both storage conditions. In contrast, when plasma ChE activity was inhibited by either antiChE, male plasma ChE activity was depressed further than female ChE (P less than 0.01) and remained constant during storage while female ChE activity continued to decrease (P less than 0.05). These divergent effects of exposure to antiChE compounds and sample storage indicate extreme care should be exercised in use of blood plasma for evaluation of antiChE exposure in wild birds.     

Tetramethonium derivatives as reversible inhibitors of various cholinesterases

To study the effect of the onium atom nature on anticholinesterase efficiency, we tested elementorganic derivatives of tetramethylenbisonium compounds as reversible inhibitors of the following cholinesterases (ChE): acetyl-ChE from human erythrocytes, butyryl-ChE from horse serum, ChE from the brain of the grass frog Rana temporaria, ChEs from visual ganglia of the Pacific squid Todarodes pacificus, and ChE from visual ganglia of the commander squid Berryteuthis magister from different habitats in the Northwestern Pacific Ocean. Bisphosphonium inhibitors were found to be much stronger effectors than bisammonum compounds, although this may be due to a significantly increased size and hydrophobicity of their onium groups. Bisammonium organosilicon compound and its monoammonium analog were equally active as reversible ChE inhibitors in mammals. The first studied bis(phenyliodonium) derivative, which is characterized by a significantly increased hydrophobicity due to the introduction of fluorine atoms to the interonium tetramethylene chain, also exhibited a pronounced anticholinesterase effect on mammalian ChE.     

Regional cholinesterase activity in white-throated sparrow brain is differentially affected by acephate (orthene®)

Effects of a 14-day dietary exposure to an organophosphorus pesticide, acephate (acetylphosphoramidothioic acid O,S-dimethyl ester), were determined on cholinesterase activity in three regions (basal ganglia, hippocampus, and hypothalamus) of the white-throated sparrow, Zonotrichia albicollis, brain. All three regions experienced depressed cholinesterase activity between 0.5–2 ppm acephate. The regions exhibited cholinesterase recovery at 2–16 ppm acephate; however, cholinesterase activity dropped and showed no recovery at higher dietary levels (>16 ppm acephate). Evidence indicates that the recovery is initiated by the magnitude of depression, not the duration. In general, as acephate concentration increased, differences in ChE activity among brain regions decreased. Three terms are introduced to describe ChE response to acephate exposure: 1) ChE resistance threshold, 2) ChE compensation threshold, and 3) ChE depression threshold. It is hypothesized that adverse effects to birds in the field may occur at pesticide exposure levels customarily considered negligible.     

Combined effect of short-term dehydration and sublethal acute oral dicrotophos exposure confounds the diagnosis of anticholinesterase exposure in common quail (Coturnix coturnix) using plasma cholinesterase activity

Common Quail (Coturnix coturnix) were subjected to controlled and replicated experiments in the summer of 2008 to investigate the effects of short-term dehydration on cholinesterase activity in brain and plasma and the interaction between dehydration and exposure to the organophosphorus pesticide dicrotophos in these same tissues. Our objective was to determine if dehydration could confound the diagnosis of anticholinesterase exposure using inhibition of cholinesterase activity in quail tissues. The effect of dehydration was quantified using measures of plasma osmolality and hematocrit. Dicrotophos exposure caused significant inhibition of cholinesterase activity in brain, while the effects of dehydration and interaction were not significant. Dehydration caused significant duration-dependent increases in plasma osmolality and hematocrit. Dehydration also caused a significant increase in plasma cholinesterase activity. Variation in the change in plasma cholinesterase activity in response to dehydration was significantly and positively correlated with dehydration-induced variation in both the change in plasma osmolality and the change in hematocrit. These correlations suggest that plasma cholinesterase activity in quail is not limited to plasma but occupies some larger pool of the extracellular fluid volume, and we suggest lymph is part of that pool. The effects of dehydration on plasma cholinesterase activity masked the inhibitory effects of dicrotophos. Here, the combination of dehydration and dicrotophos exposure produced plasma cholinesterase activity that was not significantly different from reference and pre-exposure values, confounding the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail. A method to adjust plasma cholinesterase activities for the confounding effects of dehydration and enable the diagnosis of anticholinesterase exposure in dehydrated, dicrotophos-exposed quail was developed. Clinicians and practitioners responsible for the diagnosis of anticholinesterase exposure in birds are cautioned that dehydration, commonly observed in sick wildlife, may mask the effect of anticholinesterases on plasma cholinesterase activity.     

巴音布鲁克大尤尔都斯盆地野生种子植物区系研究

基于野外实地调查,采集植物标本鉴定并结合相关文献资料整理,构建新疆巴音布鲁克大尤尔都斯盆地野生种子植物名录,在此基础上对该地区野生种子植物区系进行研究.结果表明:(1)巴音布鲁克大尤尔都斯盆地共有野生种子植物60科261属770种.(2)优势科有禾本科、菊科、豆科、石竹科、蔷薇科、十字花科、莎草科、毛茛科等11个科,表征科有豆科、龙胆科、石竹科、禾本科4个科.(3)区系地理成分以温带分布型为主,其中在科级水平上,温带分布型所属科共有30科,占到总科数(不含世界广布科)的88.24％;在属级水平上,温带性质分布型的属有220属,占总属数(不含世界广布属)的97.78％;同时该地区植物物种与地中海、中亚、西亚交流相对较多,而与东亚和热带交流很少.(1)本地区无中国特有属,但有中国特有种55个,其中新疆特有种32个.     

贡嘎山典型植被地上生物量与碳储量研究

采用典型样地调查和异速生长模型相结合的方法,测定了贡嘎山东坡垂直带谱上常绿与落叶阔叶混交林、针阔叶混交林、亚高山暗针叶林、高山灌丛4种典型植被类型的地上部分生物量与碳储量.结果表明,(1)随着海拔的升高,植被地上生物量呈先上升后下降的趋势,其生物量分别为:常绿与落叶阔叶混交林233.49 t/hm2、针阔叶混交林524.55 t/hm2、暗针叶林415.81 t/hm2、高山灌丛20.86 t/hm2,而相应的单株树木平均地上生物量分别为320.11 kg、1 140.78 kg、623.15 kg、11.89 kg,显示出与植被垂直带生物量相一致的变化趋势.(2)不同树木器官的含碳率中,以叶片的平均含碳率(48.25％)最高,依次为树枝(4 6.29％)、树干(4 4.65％);海拔从低到高的4个垂直带植被碳储量分别为103.60 t/hm2、245.26 t/hm2、192.99 t/hm2、9.82 t/hm2.研究认为,年平均降水量与地上生物量显著相关,是影响贡嘎山植被垂直带地上生物量分异的重要气候因子.     

新疆中天山野生种子植物区系分析

基于野外调查,采集植物标本以及对相关文献资料进行整理,构建中天山野生种子植物名录,在此基础上对该地区野生种子植物区系进行分析.结果表明:(1)中天山地区共有野生种子植物81科453属1 567种;(2)优势科有菊科、禾本科、豆科、十字花科、唇形科、毛茛科等17科,表征科有石竹科、莎草科、百合科、茜草科、龙胆科、禾本科、蓼科等7科;(3)区系地理成分以温带分布型为主,其中科级水平上,温带分布型所属科共有36科,占到总科数(不含世界广布科)的76.60％.属级水平上,温带性质分布型的属有377属,占总属数的94.96％.同时该地区植物物种与地中海、中亚、西亚交流相对较多,与东亚交流很少.     

Birds rarely hybridize: A citizen science approach to estimating rates of hybridization in the wild*

The rate of hybridization among taxa is a central consideration in any discussion of speciation, but rates of hybridization are difficult to estimate in most wild populations of animals. We used a successful citizen science dataset, eBird, to estimate the rates of hybridization for wild birds in the United States. We calculated the frequency at which hybrid individuals belonging to different species, families, and orders of birds were observed. Between 1 January 2010 and 31 December 2018, a total of 334,770,194 species records were reported to eBird within the United States. Of this total, 212,875 or 0.064% were reported as hybrids. This estimate is higher than the rate of hybridization (0.00167%) reported by Mayr based on impressions from a career studying museum specimens. However, if the 10 most influential hybrid species are removed from the eBird dataset, the rate of hybridization decreases substantially to about 0.009%. We conclude that the rate of hybridization for individuals in most bird species is extremely low, even though the potential for birds to produce fertile offspring through hybrid crosses is high. These findings indicate that there is strong prezygotic selection working in most avian species.     

利用红外相机技术监测道路对野生动物丰富度的影响——以观音山国家级自然保护区道路为例

2014年7月至2018年10月,利用20台红外相机监测陕西观音山国家级自然保护区一条内部道路对兽类和鸟类活动的影响.监测期间获得照片16168张,共鉴定到13种兽类和14种鸟类,包括4种国家Ⅰ级重点保护野生动物和7种国家Ⅱ级重点保护野生动物.结果 显示,距道路的距离越远,出现的物种种类越多.有2种兽类只活动于距离道路...