贻贝是全球范围内具有重要经济价值和生态价值的双壳贝类。贻贝抗菌肽具有极强的分子多样性,也是当前抗菌肽研究的重要对象。防御素是贻贝抗菌肽的重要成员,从厚壳贻贝中鉴定到2种新型防御素,但其分子特性和免疫机制尚不清楚。为此,对...贻贝是全球范围内具有重要经济价值和生态价值的双壳贝类。贻贝抗菌肽具有极强的分子多样性,也是当前抗菌肽研究的重要对象。防御素是贻贝抗菌肽的重要成员,从厚壳贻贝中鉴定到2种新型防御素,但其分子特性和免疫机制尚不清楚。为此,对厚壳贻贝体内新发现的2种防御素开展研究。序列分析结果表明,2种新型防御素均具有节肢动物防御素结构特征,因而被命名为arthropod like defensin(ALD)。利用荧光定量PCR研究了2种防御素在贻贝不同组织及不同发育阶段的表达量差异。进一步分析了2种防御素在3种不同微生物诱导下的表达量时间曲线。利用固相化学合成技术对2种防御素的成熟肽区进行合成并开展了功能验证。研究结果表明,2种ALD主要表达部位在外套膜和消化腺,且ALD-1具有雄性特异表达特征。此外,ALD-1和ALD-2在贻贝幼虫阶段均未表达;在不同微生物刺激下,2种ALD表现出不同的免疫反应模式,显示出2种防御素具有不同的免疫调节机制。化学合成的2种ALD均具有抑菌活性,其对不同微生物的抑制率在20%~80%之间。上述研究为深入了解贻贝免疫防御的分子机制,以及贻贝抗菌肽的免疫功能和后续的分子资源开发奠定了基础。展开更多
Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling....Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds展开更多
Circular patterns, or eyespots, are common anti-predator features in a variety of animals. Two defensive functions have been documented： large eyespots may intimidate predators, whereas smaller marginal eyespots may ...Circular patterns, or eyespots, are common anti-predator features in a variety of animals. Two defensive functions have been documented： large eyespots may intimidate predators, whereas smaller marginal eyespots may divert attacks. However, a given eyespot potentially serves both functions, possibly depending on the predator＇s size and/or experience. Naive predators are potentially more likely to misdirect their attacks towards eyespots; alternatively, their typically smaller size would make them more intimidated by the same eyespots. Here we test how juvenile and sub-adult naive chickens respond to a single eyespot on a butterfly＇s wing. We presented the birds with dead wall brown butterflies, Lasiommata megera, that had their apical eyespot visible or painted over. We assessed the birds＇ responses＇ by （i） scoring their intimidation reaction, （ii） whether they uttered alarm calls and, （iii） if they attacked the butterfly and where they targeted their attacks. Results show that both age categories received higher intimidation scores when offered a butterfly with a visible eyespot. Juveniles were more intimidated by the butterfly than the sub-adults： they received higher intimidation scores and were more prone to utter alarm calls. Moreover, only sub-adults at- tacked and did so by preferentially attacking the butterfly＇s anterior. We demonstrate an intimidating effect of the type of eyespot that has previously been shown only to divert attacks. We suggest that one and the same eyespot may serve two functions relative to different predators; however, further experiments are needed to disentangle the role of predator identity and its link to size, on- togeny and experience [Current Zoology 61 （4）： 749-757, 2015].展开更多
Aims Plants have limited resources for defenses and species that invest in biotic defenses might exhibit leaves that invest less in other types of defenses.We have investigated whether plants that have few mechanical ...Aims Plants have limited resources for defenses and species that invest in biotic defenses might exhibit leaves that invest less in other types of defenses.We have investigated whether plants that have few mechanical defenses,but have extrafloral nectaries(EFNs)patrolled by ants,are less prone to herbivory,compared with plants without EFNs that have tougher leaves.Methods Data from the literature were extracted to examine the reported levels of herbivory in plants with or without EFNs.In a savanna vegetation in southern Brazil,field data were collected in leaves from six tropical species and herbivory and specific leaf area(SLA)levels were measured.We further evaluated differences in herbivory and SLA among species and between plants with or without EFNs.In order to test the relationship between herbivory and leaf toughness we regressed average herbivory and average SLA per plant.Important Findings Plants exhibited variable levels of leaf damage,but plants without ant defenses experienced the highest levels of leaf area loss to herbivory.Levels of mechanical defenses were also variable among the plant species.Plants without EFNs were tougher,exhibiting lower values of SLA.Although plants without EFNs had more sclerophyllous leaves,this mechanical defense was not sufficient to impair and/or reduce herbivore feeding,suggesting that the biotic defenses performed by patrolling ants might be more effective than investment in mechanical defenses associated with leaf palatability.展开更多
Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size an...Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators.展开更多
文摘贻贝是全球范围内具有重要经济价值和生态价值的双壳贝类。贻贝抗菌肽具有极强的分子多样性,也是当前抗菌肽研究的重要对象。防御素是贻贝抗菌肽的重要成员,从厚壳贻贝中鉴定到2种新型防御素,但其分子特性和免疫机制尚不清楚。为此,对厚壳贻贝体内新发现的2种防御素开展研究。序列分析结果表明,2种新型防御素均具有节肢动物防御素结构特征,因而被命名为arthropod like defensin(ALD)。利用荧光定量PCR研究了2种防御素在贻贝不同组织及不同发育阶段的表达量差异。进一步分析了2种防御素在3种不同微生物诱导下的表达量时间曲线。利用固相化学合成技术对2种防御素的成熟肽区进行合成并开展了功能验证。研究结果表明,2种ALD主要表达部位在外套膜和消化腺,且ALD-1具有雄性特异表达特征。此外,ALD-1和ALD-2在贻贝幼虫阶段均未表达;在不同微生物刺激下,2种ALD表现出不同的免疫反应模式,显示出2种防御素具有不同的免疫调节机制。化学合成的2种ALD均具有抑菌活性,其对不同微生物的抑制率在20%~80%之间。上述研究为深入了解贻贝免疫防御的分子机制,以及贻贝抗菌肽的免疫功能和后续的分子资源开发奠定了基础。
文摘Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds
文摘Circular patterns, or eyespots, are common anti-predator features in a variety of animals. Two defensive functions have been documented： large eyespots may intimidate predators, whereas smaller marginal eyespots may divert attacks. However, a given eyespot potentially serves both functions, possibly depending on the predator＇s size and/or experience. Naive predators are potentially more likely to misdirect their attacks towards eyespots; alternatively, their typically smaller size would make them more intimidated by the same eyespots. Here we test how juvenile and sub-adult naive chickens respond to a single eyespot on a butterfly＇s wing. We presented the birds with dead wall brown butterflies, Lasiommata megera, that had their apical eyespot visible or painted over. We assessed the birds＇ responses＇ by （i） scoring their intimidation reaction, （ii） whether they uttered alarm calls and, （iii） if they attacked the butterfly and where they targeted their attacks. Results show that both age categories received higher intimidation scores when offered a butterfly with a visible eyespot. Juveniles were more intimidated by the butterfly than the sub-adults： they received higher intimidation scores and were more prone to utter alarm calls. Moreover, only sub-adults at- tacked and did so by preferentially attacking the butterfly＇s anterior. We demonstrate an intimidating effect of the type of eyespot that has previously been shown only to divert attacks. We suggest that one and the same eyespot may serve two functions relative to different predators; however, further experiments are needed to disentangle the role of predator identity and its link to size, on- togeny and experience [Current Zoology 61 （4）： 749-757, 2015].
基金supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil(CAPES)-(Finance Code 001)Conselho Nacional de Desenvolvimento Científico e Tecnológico(307210/2016-2).
文摘Aims Plants have limited resources for defenses and species that invest in biotic defenses might exhibit leaves that invest less in other types of defenses.We have investigated whether plants that have few mechanical defenses,but have extrafloral nectaries(EFNs)patrolled by ants,are less prone to herbivory,compared with plants without EFNs that have tougher leaves.Methods Data from the literature were extracted to examine the reported levels of herbivory in plants with or without EFNs.In a savanna vegetation in southern Brazil,field data were collected in leaves from six tropical species and herbivory and specific leaf area(SLA)levels were measured.We further evaluated differences in herbivory and SLA among species and between plants with or without EFNs.In order to test the relationship between herbivory and leaf toughness we regressed average herbivory and average SLA per plant.Important Findings Plants exhibited variable levels of leaf damage,but plants without ant defenses experienced the highest levels of leaf area loss to herbivory.Levels of mechanical defenses were also variable among the plant species.Plants without EFNs were tougher,exhibiting lower values of SLA.Although plants without EFNs had more sclerophyllous leaves,this mechanical defense was not sufficient to impair and/or reduce herbivore feeding,suggesting that the biotic defenses performed by patrolling ants might be more effective than investment in mechanical defenses associated with leaf palatability.
文摘Abstract Many rodents exhibit inducible defenses when exposed to chemical cues from mammalian predators. These responses may include delays in sexual maturation, smaller adult body size and decreases in litter size and pup weight. We exposed the hybrid juvenile offspring of field-caught and lab-descended house mice Mus musculus to the chemical cues of mouse-fed or chick-fed kingsnakes, Lampropeltis getula, for 20 days after weaning, to examine the effects of ophidian predator cues on prey development. We hypothesized that these cues would elicit inducible defenses such as alteration of growth rates, and/or the timing of reproductive development in mice. Once mature, the reproductive effort of the mice might also be impacted by producing smaller litter sizes or lighter pups or not reproducing at all. We found no effect of kingsnake cues on any of the measures. These findings support the hypothesis that inducible defenses may have evolved as a strategy to deal with specific predators.
