Many insects feed on a low‐nitrogen diet,and the origin of their nitrogen supply is poorly understood.It has been hypothesized that some insects rely on nitrogen‐fixing bacteria(diazotrophs)to supplement their diets...Many insects feed on a low‐nitrogen diet,and the origin of their nitrogen supply is poorly understood.It has been hypothesized that some insects rely on nitrogen‐fixing bacteria(diazotrophs)to supplement their diets.Nitrogen fixation by diazotrophs has been extensively studied and convincingly demonstrated in termites,while evidence for the occurrence and role of nitrogen fixation in the diet of other insects is less conclusive.Here,we summarize the methods to detect nitrogen fixation in insects and review the available evidence for its occurrence(focusing on insects other than termites).We distinguish between three aspects of nitrogen fixation investigations:(i)detecting the presence of potential diazotrophs;(ii)detecting the activity of the nitrogen‐fixing enzyme;and(iii)detecting the assimilation of fixed nitrogen into the insect tissues.We show that although evidence from investigations of the first aspect reveals ample opportunities for interactions with potential diazotrophs in a variety of insects,demonstrations of actual biological nitrogen fixation and the assimilation of fixed nitrogen are restricted to very few insect groups,including wood‐feeding beetles,fruit flies,leafcutter ants,and a wood wasp.We then discuss potential implications for the insect's fitness and for the ecosystem as a whole.We suggest that combining these multiple approaches is crucial for the study of nitrogen fixation in insects,and argue that further demonstrations are desperately needed in order to determine the relative importance of diazotrophs for insect diet and fitness,as well as to evaluate their overall impact on the ecosystem.展开更多
Brucellosis is a zoonotic disease caused by a number of bacteria in the genus Brucella.In animals,classical Brucella species naturally affiliate with mammals in which they cause epididymitis and orchitis in males and ...Brucellosis is a zoonotic disease caused by a number of bacteria in the genus Brucella.In animals,classical Brucella species naturally affiliate with mammals in which they cause epididymitis and orchitis in males and abortion storms in pregnant females.Because Brucella proliferates to a vast number of free organisms in the fetal organs and fluids,abortion plays a key mechanism in disease spread in nature.B.melitensis,B.suis,and B.abortus construct the three most severe zoonotic species and their role in human brucellosis stems from their association with domesticated farm animals in which they strive and transmit the disease.Here we review the relevant literature on genus Brucella,vaccination and diagnostic approaches.Meanwhile,the prevention and control programs based on the combination of vaccination coverage of the population with differentiating serological diagnosis of the infected from vaccinated animals(DIVA)and herd clearance by a test and cull strategy using validated serological tests were discussed.展开更多
基金We thank Tamir Rosenberg for technical support.We thank Shimon Rachmilevitch,Martin Kaltenpoth,and Itamar Gilady for discussions and comments on earlier versions of the manuscript.We thank the Daniel E.Koshland Fund,the Sol Leshin Program for BGU-UCLA Academic Cooperation,and the Israel Science Foundation(Award No.364/16)for supporting this work.This is publication number 1032 of the Mitrani Department of Desert Ecology。
文摘Many insects feed on a low‐nitrogen diet,and the origin of their nitrogen supply is poorly understood.It has been hypothesized that some insects rely on nitrogen‐fixing bacteria(diazotrophs)to supplement their diets.Nitrogen fixation by diazotrophs has been extensively studied and convincingly demonstrated in termites,while evidence for the occurrence and role of nitrogen fixation in the diet of other insects is less conclusive.Here,we summarize the methods to detect nitrogen fixation in insects and review the available evidence for its occurrence(focusing on insects other than termites).We distinguish between three aspects of nitrogen fixation investigations:(i)detecting the presence of potential diazotrophs;(ii)detecting the activity of the nitrogen‐fixing enzyme;and(iii)detecting the assimilation of fixed nitrogen into the insect tissues.We show that although evidence from investigations of the first aspect reveals ample opportunities for interactions with potential diazotrophs in a variety of insects,demonstrations of actual biological nitrogen fixation and the assimilation of fixed nitrogen are restricted to very few insect groups,including wood‐feeding beetles,fruit flies,leafcutter ants,and a wood wasp.We then discuss potential implications for the insect's fitness and for the ecosystem as a whole.We suggest that combining these multiple approaches is crucial for the study of nitrogen fixation in insects,and argue that further demonstrations are desperately needed in order to determine the relative importance of diazotrophs for insect diet and fitness,as well as to evaluate their overall impact on the ecosystem.
基金supported by National Key Research and Development Program of China(NO.2016YFD0500902)Salaries and research support were also provided by funds appropriated to the China Institute of Veterinary Drug Control.
文摘Brucellosis is a zoonotic disease caused by a number of bacteria in the genus Brucella.In animals,classical Brucella species naturally affiliate with mammals in which they cause epididymitis and orchitis in males and abortion storms in pregnant females.Because Brucella proliferates to a vast number of free organisms in the fetal organs and fluids,abortion plays a key mechanism in disease spread in nature.B.melitensis,B.suis,and B.abortus construct the three most severe zoonotic species and their role in human brucellosis stems from their association with domesticated farm animals in which they strive and transmit the disease.Here we review the relevant literature on genus Brucella,vaccination and diagnostic approaches.Meanwhile,the prevention and control programs based on the combination of vaccination coverage of the population with differentiating serological diagnosis of the infected from vaccinated animals(DIVA)and herd clearance by a test and cull strategy using validated serological tests were discussed.
