共查询到20条相似文献,搜索用时 15 毫秒
1.
A. H. C. McLean M. van Asch J. Ferrari H. C. J. Godfray 《Proceedings. Biological sciences / The Royal Society》2011,278(1706):760-766
Aphids possess several facultative bacterial symbionts that have important effects on their hosts'' biology. These have been most closely studied in the pea aphid (Acyrthosiphon pisum), a species that feeds on multiple host plants. Whether secondary symbionts influence host plant utilization is unclear. We report the fitness consequences of introducing different strains of the symbiont Hamiltonella defensa into three aphid clones collected on Lathyrus pratensis that naturally lack symbionts, and of removing symbionts from 20 natural aphid–bacterial associations. Infection decreased fitness on Lathyrus but not on Vicia faba, a plant on which most pea aphids readily feed. This may explain the unusually low prevalence of symbionts in aphids collected on Lathyrus. There was no effect of presence of symbiont on performance of the aphids on the host plants of the clones from which the H. defensa strains were isolated. Removing the symbiont from natural aphid–bacterial associations led to an average approximate 20 per cent reduction in fecundity, both on the natural host plant and on V. faba, suggesting general rather than plant-species-specific effects of the symbiont. Throughout, we find significant genetic variation among aphid clones. The results provide no evidence that secondary symbionts have a major direct role in facilitating aphid utilization of particular host plant species. 相似文献
2.
Hukam Singh Gehlot Nisha Tak Muskan Kaushik Shubhajit Mitra Wen-Ming Chen Nicole Poweleit Dheeren Panwar Neetu Poonar Rashmita Parihar Alkesh Tak Indu Singh Sankhla Archana Ojha Satyawada Rama Rao Marcelo F. Simon Fabio Bueno dos Reis Junior Natalia Perigolo Anil K. Tripathi Janet I. Sprent J. Peter W. Young Euan K. James Prasad Gyaneshwar 《Annals of botany》2013,112(1):179-196
Background and Aims
The large monophyletic genus Mimosa comprises approx. 500 species, most of which are native to the New World, with Central Brazil being the main centre of radiation. All Brazilian Mimosa spp. so far examined are nodulated by rhizobia in the betaproteobacterial genus Burkholderia. Approximately 10 Mya, transoceanic dispersal resulted in the Indian subcontinent hosting up to six endemic Mimosa spp. The nodulation ability and rhizobial symbionts of two of these, M. hamata and M. himalayana, both from north-west India, are here examined, and compared with those of M. pudica, an invasive species.Methods
Nodules were collected from several locations, and examined by light and electron microscopy. Rhizobia isolated from them were characterized in terms of their abilities to nodulate the three Mimosa hosts. The molecular phylogenetic relationships of the rhizobia were determined by analysis of 16S rRNA, nifH and nodA gene sequences.Key Results
Both native Indian Mimosa spp. nodulated effectively in their respective rhizosphere soils. Based on 16S rRNA, nifH and nodA sequences, their symbionts were identified as belonging to the alphaproteobacterial genus Ensifer, and were closest to the ‘Old World’ Ensifer saheli, E. kostiensis and E. arboris. In contrast, the invasive M. pudica was predominantly nodulated by Betaproteobacteria in the genera Cupriavidus and Burkholderia. All rhizobial strains tested effectively nodulated their original hosts, but the symbionts of the native species could not nodulate M. pudica.Conclusions
The native Mimosa spp. in India are not nodulated by the Burkholderia symbionts of their South American relatives, but by a unique group of alpha-rhizobial microsymbionts that are closely related to the ‘local’ Old World Ensifer symbionts of other mimosoid legumes in north-west India. They appear not to share symbionts with the invasive M. pudica, symbionts of which are mostly beta-rhizobial. 相似文献3.
The display of courtship behavior has evolved in response to sexual selection driven by competition to obtain mates. Sexually dimorphic mate selection rituals are likely controlled at least in part by genes with sex-biased patterns of expression. In Drosophila melanogaster, male courtship behavior has been well described and consists of a series of stereotyped behaviors. The takeout gene is predominantly expressed in males and affects male courtship behavior. In this study, we examine the patterns of expression and evolution in takeout and the family of related proteins. We show that a number of genes in the takeout gene family show male-biased expression in D. melanogaster, largely in non-reproductive tissues. Phylogenetic analysis reveals that this gene family is conserved across insects. As expected for genes with male-biased expression, we also find evidence of positive selection in some lineages. Our results suggest that the genes in this family may have evolutionarily conserved sex specific roles in male mating behavior across insects. 相似文献
4.
Paulina Giraldo-Perez Matthew R. Goddard 《Proceedings. Biological sciences / The Royal Society》2013,280(1770)
Selfish genes demonstrate transmission bias and invade sexual populations despite conferring no benefit to their hosts. While the molecular genetics and evolutionary dynamics of selfish genes are reasonably well characterized, their effects on hosts are not. Homing endonuclease genes (HEGs) are one well-studied family of selfish genes that are assumed to be benign. However, we show that carrying HEGs is costly for Saccharomyces cerevisiae, demonstrating that these genetic elements are not necessarily benign but maybe parasitic. We estimate a selective load of approximately 1–2% in ‘natural’ niches. The second aspect we examine is the ability of HEGs to affect hosts'' sexual behaviour. As all selfish genes critically rely on sex for spread, then any selfish gene correlated with increased host sexuality will enjoy a transmission advantage. While classic parasites are known to manipulate host behaviour, we are not aware of any evidence showing a selfish gene is capable of affecting host promiscuity. The data presented here show a selfish element may increase the propensity of its eukaryote host to undergo sex and along with increased rates of non-Mendelian inheritance, this may counterbalance mitotic selective load and promote spread. Demonstration that selfish genes are correlated with increased promiscuity in eukaryotes connects with ideas suggesting that selfish genes promoted the evolution of sex initially. 相似文献
5.
A new species, Larinus berti
sp. n. is described from Morocco and assigned to subgenus Cryphopus Petri, 1907 (Curculionidae: Lixinae; Lixini). Diagnostic characters of the new species are large size, elongate-ovate body, bisulcate sub-quadrangular rostrum, triangularly raised dorsum of rostrum, flat subgena and submentum, Y-shaped apodeme of sternite VIII of female and thin nodulus of spermatheca. 相似文献
6.
7.
Laia Batalla-Carrera Ana Morton David Shapiro-Ilan Michael R. Strand Fernando García-del-Pino 《Journal of nematology》2014,46(3):281-286
We investigated the existing susceptibility differences of the hazelnut weevil, Curculio nucum L. (Coleoptera:, Curculionidae) to entomopathogenic nematodes by assessing the main route of entry of the nematodes, Steinernema carpocapsae strain B14 and S. feltiae strain D114, into larvae and adult insects, as well as host immune response. Our results suggested that S. carpocapsae B14 and S. feltiae D114 primarily entered adult insects and larvae through the anus. Larvae were more susceptible to S. feltiae D114 than S. carpocapsae B14 and adults were highly susceptible to S. carpocapsae B14 but displayed low susceptibility to S. feltiae D114. Penetration rate correlated with nematode virulence. We observed little evidence that hazelnut weevils mounted any cellular immune response toward S. carpocapsae B14 or S. feltiae D114. We conclude the differential susceptibility of hazelnut weevil larvae and adults to S. carpocapsae B14 and S. feltiae D114 primarily reflected differences in the ability of these two nematodes to penetrate the host. 相似文献
8.
Rough lemon seedlings were grown in mycorrhizal-infested or phosphorus-amended soil (25 and 300 mg P/kg) in greenhouse experiments. Plants Were inoculated with the citrus burrowing nematode, Radopholus citrophilus (0, 50, 100, or 200 nematodes per pot). Six months later, mycorrhizal plants and nonmycorrhizal, high-P plants had larger shoot and root weights than did non-mycorrhizal, low-P plants. Burrowing nematode population densities were lower in roots of mycorrhizal or nonmycorrhizal, high-P plants than in roots of nonmycorrhizal, low-P plants; however, differences in plant growth between mycorrhizal and nonmycorrhizal plants were not significant with respect to initial nematode inoculum densities. Phosphorus content in leaf tissue was significantly greater in mycorrhizal and nonmycorrhizal, high-P plants compared with nonmycorrhizal, low-P plants. Nutrient concentrations of K, Mg, and Zn were unaffected by nematode parasitism, whereas P, Ca, Fe, and Mn were less in nematode-infected plants. Enhanced growth associated with root colonization by the mycorrhizal fungus appeared to result from improved P nutrition and not antagonism between the fungus and the nematode. 相似文献
9.
Jun-Bo Luan Hong-Wei Shan Philipp Isermann Jia-Hsin Huang Jan Lammerding Shu-Sheng Liu Angela E. Douglas 《Proceedings. Biological sciences / The Royal Society》2016,283(1833)
Various insects require intracellular bacteria that are restricted to specialized cells (bacteriocytes) and are transmitted vertically via the female ovary, but the transmission mechanisms are obscure. We hypothesized that, in the whitefly Bemisia tabaci, where intact bacteriocytes (and not isolated bacteria) are transferred to oocytes, the transmission mechanism would be evident as cellular and molecular differences between the nymph (pre-adult) and adult bacteriocytes. We demonstrate dramatic remodelling of bacteriocytes at the developmental transition from nymph to adulthood. This transition involves the loss of cell–cell adhesion, high division rates to constant cell size and onset of cell mobility, enabling the bacteriocytes to crawl to the ovaries. These changes are accompanied by cytoskeleton reorganization and changes in gene expression: genes functioning in cell–cell adhesion display reduced expression and genes involved in cell division, cell motility and endocytosis/exocytosis have elevated expression in adult bacteriocytes, relative to nymph bacteriocytes. This study demonstrates, for the first time, how developmentally orchestrated remodelling of gene expression and correlated changes in cell behaviour underpin the capacity of bacteriocytes to mediate the vertical transmission and persistence of the symbiotic bacteria on which the insect host depends. 相似文献
10.
V P Edgcomb S A Breglia N Yubuki D Beaudoin D J Patterson B S Leander J M Bernhard 《The ISME journal》2011,5(2):231-243
A distinct subgroup of euglenozoans, referred to as the ‘Symbiontida,'' has been described from oxygen-depleted and sulfidic marine environments. By definition, all members of this group carry epibionts that are intimately associated with underlying mitochondrion-derived organelles beneath the surface of the hosts. We have used molecular phylogenetic and ultrastructural evidence to identify the rod-shaped epibionts of the two members of this group, Calkinsia aureus and B.bacati, hand-picked from the sediments of two separate oxygen-depleted, sulfidic environments. We identify their epibionts as closely related sulfur or sulfide-oxidizing members of the epsilon proteobacteria. The epsilon proteobacteria generally have a significant role in deep-sea habitats as primary colonizers, primary producers and/or in symbiotic associations. The epibionts likely fulfill a role in detoxifying the immediate surrounding environment for these two different hosts. The nearly identical rod-shaped epibionts on these two symbiontid hosts provides evidence for a co-evolutionary history between these two sets of partners. This hypothesis is supported by congruent tree topologies inferred from 18S and 16S rDNA from the hosts and bacterial epibionts, respectively. The eukaryotic hosts likely serve as a motile substrate that delivers the epibionts to the ideal locations with respect to the oxic/anoxic interface, whereby their growth rates can be maximized, perhaps also allowing the host to cultivate a food source. Because symbiontid isolates and additional small subunit rDNA gene sequences from this clade have now been recovered from many locations worldwide, the Symbiontida are likely more widespread and diverse than presently known. 相似文献
11.
Alexander Riedel Rene T?nzler Michael Balke Cahyo Rahmadi Yayuk R. Suhardjono 《ZooKeys》2014,(467):1-162
The genus Trigonopterus Fauvel, 1862 is highly diverse in Melanesia. Only one species, Trigonopterus
amphoralis Marshall, 1925 was so far recorded West of Wallace’s Line (Eastern Sumatra). Based on focused field-work the fauna from Sundaland (Sumatra, Java, Bali, Palawan) and the Lesser Sunda Islands (Lombok, Sumbawa, Flores) is here revised. We redescribe Trigonopterus
amphoralis Marshall and describe an additional 98 new species: Trigonopterus
acuminatus
sp. n., Trigonopterus
aeneomicans
sp. n., Trigonopterus
alaspurwensis
sp. n., Trigonopterus
allopatricus
sp. n., Trigonopterus
allotopus
sp. n., Trigonopterus
angulicollis
sp. n., Trigonopterus
argopurensis
sp. n., Trigonopterus
arjunensis
sp. n., Trigonopterus
asper
sp. n., Trigonopterus
attenboroughi
sp. n., Trigonopterus
baliensis
sp. n., Trigonopterus
batukarensis
sp. n., Trigonopterus
bawangensis
sp. n., Trigonopterus
binodulus
sp. n., Trigonopterus
bornensis
sp. n., Trigonopterus
cahyoi
sp. n., Trigonopterus
costipennis
sp. n., Trigonopterus
cuprescens
sp. n., Trigonopterus
cupreus
sp. n., Trigonopterus
dacrycarpi
sp. n., Trigonopterus
delapan
sp. n., Trigonopterus
dentipes
sp. n., Trigonopterus
diengensis
sp. n., Trigonopterus
dimorphus
sp. n., Trigonopterus
disruptus
sp. n., Trigonopterus
dua
sp. n., Trigonopterus
duabelas
sp. n., Trigonopterus
echinatus
sp. n., Trigonopterus
empat
sp. n., Trigonopterus
enam
sp. n., Trigonopterus
fissitarsis
sp. n., Trigonopterus
florensis
sp. n., Trigonopterus
foveatus
sp. n., Trigonopterus
fulgidus
sp. n., Trigonopterus
gedensis
sp. n., Trigonopterus
halimunensis
sp. n., Trigonopterus
honjensis
sp. n., Trigonopterus
ijensis
sp. n., Trigonopterus
javensis
sp. n., Trigonopterus
kalimantanensis
sp. n., Trigonopterus
kintamanensis
sp. n., Trigonopterus
klatakanensis
sp. n., Trigonopterus
lampungensis
sp. n., Trigonopterus
latipes
sp. n., Trigonopterus
lima
sp. n., Trigonopterus
lombokensis
sp. n., Trigonopterus
merubetirensis
sp. n., Trigonopterus
mesehensis
sp. n., Trigonopterus
micans
sp. n., Trigonopterus
misellus
sp. n., Trigonopterus
palawanensis
sp. n., Trigonopterus
pangandaranensis
sp. n., Trigonopterus
paraflorensis
sp. n., Trigonopterus
pararugosus
sp. n., Trigonopterus
parasumbawensis
sp. n., Trigonopterus
pauxillus
sp. n., Trigonopterus
payungensis
sp. n., Trigonopterus
porcatus
sp. n., Trigonopterus
pseudoflorensis
sp. n., Trigonopterus
pseudosumbawensis
sp. n., Trigonopterus
punctatoseriatus
sp. n., Trigonopterus
ranakensis
sp. n., Trigonopterus
relictus
sp. n., Trigonopterus
rinjaniensis
sp. n., Trigonopterus
roensis
sp. n., Trigonopterus
rugosostriatus
sp. n., Trigonopterus
rugosus
sp. n., Trigonopterus
rutengensis
sp. n., Trigonopterus
saltator
sp. n., Trigonopterus
santubongensis
sp. n., Trigonopterus
sasak
sp. n., Trigonopterus
satu
sp. n., Trigonopterus
schulzi
sp. n., Trigonopterus
sebelas
sp. n., Trigonopterus
sembilan
sp. n., Trigonopterus
sepuluh
sp. n., Trigonopterus
seriatus
sp. n., Trigonopterus
serratifemur
sp. n., Trigonopterus
setifer
sp. n., Trigonopterus
silvestris
sp. n., Trigonopterus
singkawangensis
sp. n., Trigonopterus
singularis
sp. n., Trigonopterus
sinuatus
sp. n., Trigonopterus
squalidus
sp. n., Trigonopterus
sumatrensis
sp. n., Trigonopterus
sumbawensis
sp. n., Trigonopterus
sundaicus
sp. n., Trigonopterus
suturalis
sp. n., Trigonopterus
syarbis
sp. n., Trigonopterus
telagensis
sp. n., Trigonopterus
tepalensis
sp. n., Trigonopterus
tiga
sp. n., Trigonopterus
trigonopterus
sp. n., Trigonopterus
tujuh
sp. n., Trigonopterus
ujungkulonensis
sp. n., Trigonopterus
variolosus
sp. n., Trigonopterus
vulcanicus
sp. n., Trigonopterus
wallacei
sp. n.. All new species are authored by the taxonomist-in-charge, Alexander Riedel. Most species belong to the litter fauna of primary wet evergreen forests. This habitat has become highly fragmented in the study area and many of its remnants harbor endemic species. Conservation measures should be intensified, especially in smaller and less famous sites to minimize the number of species threatened by extinction. 相似文献
12.
13.
Several deep-sea mussels and their associated symbionts are able to live both on wood and on whale falls 总被引:1,自引:0,他引:1
Lorion J Duperron S Gros O Cruaud C Samadi S 《Proceedings. Biological sciences / The Royal Society》2009,276(1654):177-185
Bathymodiolin mussels occur at hydrothermal vents and cold seeps, where they thrive thanks to symbiotic associations with chemotrophic bacteria. Closely related genera Idas and Adipicola are associated with organic falls, ecosystems that have been suggested as potential evolutionary 'stepping stones' in the colonization of deeper and more sulphide-rich environments. Such a scenario should result from specializations to given environments from species with larger ecological niches. This study provides molecular-based evidence for the existence of two mussel species found both on sunken wood and bones. Each species specifically harbours one bacterial phylotype corresponding to thioautotrophic bacteria related to other bathymodiolin symbionts. Phylogenetic patterns between hosts and symbionts are partially congruent. However, active endocytosis and occurrences of minor symbiont lineages within species which are not their usual host suggest an environmental or horizontal rather than strictly vertical transmission of symbionts. Although the bacteria are close relatives, their localization is intracellular in one mussel species and extracellular in the other, suggesting that habitat choice is independent of the symbiont localization. The variation of bacterial densities in host tissues is related to the substrate on which specimens were sampled and could explain the abilities of host species to adapt to various substrates. 相似文献
14.
15.
16.
Development of symbionts in triatomine bugs and the effects of infections with trypanosomatids 总被引:5,自引:0,他引:5
In the intestinal tract of fifth instars of the hematophagous reduviid bugs Rhodnius prolixus and Triatoma infestans blood ingestion induced an initial decrease of the concentration of the respective symbiotic bacteria Rhodococcus rhodnii and Nocardia sp. and then within 10 days a 15- or 18-fold increase of the total population/bug to about 0.8 x 10(9) colony-forming units in R. prolixus and 1.8 x 10(9) colony-forming units in T. infestans. About 95-99% of the total populations of both symbionts developed in the anterior midgut regions, i.e., cardia and stomach. The passage from the blood-storing stomach to the digesting small intestine caused a considerable breakdown of symbiont populations, and only about 0.01% of the total population was present in the rectum. These were excreted mainly within 4 h after a blood meal. After infection with three species of trypanosomatids, R. rhodnii, the symbiont of R. prolixus, was affected by Trypanosoma rangeli, but not by Blastocrithidia triatomae or Trypanosoma cruzi. On the other hand, in T. infestans the concentration of Nocardia sp. was reduced after infection with B. triatomae, but not by T. rangeli nor T. cruzi. In long-term B. triatomae-infected T. infestans, this reduction and a reduced diuretic activity after feeding synergistically lowered the symbiont concentration in the singly deposited feces/urine drops drastically compared to uninfected controls. These data strongly support the theory of the mechanisms of pathogenicity of T. rangeli and B. triatomae for R. prolixus and T. infestans, respectively, that the primal point of attack is the host-specific symbiont, R. rhodnii and Nocardia sp., respectively. 相似文献
17.
McDiarmid et al. (1999) published the first part of their planned taxonomic catalog of the snakes of the world. Since then, several new python taxa have been described in both the scientific literature and non-peer-reviewed publications. This checklist evaluates the nomenclatural status of the names and discusses the taxonomic status of the new taxa, and aims to continue the work of McDiarmid et al. (1999) for the family Pythonidae, covering the period 1999 to 2010. Numerous new taxa are listed, and where appropriate recent synonymies are included and annotations are made. A checklist and a taxonomic identification key of valid taxa are provided. 相似文献
18.
Populations of Bakernema inaequale, C. petasum, C. sphagni, C. mutabile, Ogma octangulare, Xenocriconemella macrodora and Hemicriconemoides chitwoodi were identified and re-described from different geographical areas in the continental United States and molecularly characterized. Two new species of spine nematodes Criconema arkaense n. sp. from Washington County and Lee County, Arkansas and Criconema warrenense n. sp from Warren, Bradley County, Arkansas are also described and named. Criconema arkaense is characterize by having a conspicuous lip region offset from the body with two annuli, short rounded tail with a thin cuticular sheath and subterminal anus. Criconema warrenense n. sp. has two lip region annuli about the same width, first annulus directed posteriorly, separated by a narrow neck annulus and a short conoid tail, unilobed non-folded annulus. The molecular characterization of Criconema arkaense and Criconema warrenense using ITS1 rDNA gene sequence and the molecular phylogenetic relationships of these new species along with the known spines nematodes are provided. 相似文献
19.
Elena H. Martínez-Lapiscina Cecilia Galbete Dolores Corella Estefania Toledo Pilar Buil-Cosiales Jordi Salas-Salvado Emilio Ros Miguel á. Martinez-Gonzalez 《Genes & nutrition》2014,9(3)
The traditional Mediterranean diet (MedDiet) has shown beneficial effects on cognitive decline. Nevertheless, diet–gene interactions have been poorly evaluated. We aimed to investigate diet–gene interaction in the PREDIMED-NAVARRA randomized trial. A total of 522 participants (67 ± 6 years at baseline) enrolled in the PREDIMED-NAVARRA trial were randomly allocated to one of three diets: two MedDiets (supplemented with either extra-virgin olive oil or nuts) or a low-fat diet. They were evaluated with the Mini-Mental State Examination (MMSE) and the Clock Drawing Test (CDT) after 6.5 years of intervention. Subjects were genotyped for CR1-rs3818361, CLU-rs11136000, PICALM-rs3851179 and Apolipoprotein E (ApoE) genes. We studied MedDiet–gene interactions for cognition and assessed the effect of the MedDiet on cognition across different genetic profiles. A significant interaction (p = 0.041) between CLU-rs11136000 and the MedDiet intervention on the MMSE was found with a beneficial effect of MedDiet among carriers of the T minor allele (B = 0.97, 95 % CI 0.45–1.49). Similar effect was observed for CR1-rs3818361, but no significant interaction was observed (p = 0.335). For PICALM-rs3851179, the MedDiet intervention showed a beneficial effect in both genotype groups. No apparent interaction was found for the CDT between intervention and gene variants. Similarly, participants randomly allocated to MedDiet groups, with favorable profiles of CR1, CLU and PICALM genes, significantly improved CDT scores compared to controls with the same genetic profile. Cognitive performance was better for non-ApoE4 and for ApoE4 carriers of MedDiet groups compared to controls, but for CDT performance, we only found statistical significant differences for non-ApoE4 carriers. A MedDiet intervention modulates the effect of genetic factors on cognition. The effect of MedDiet might be greater for subjects with a more favorable genetic profile. 相似文献
20.
The objective of this experiment was to determine the effects of fenamiphos 15G and short-cycle potato (PO)-sweet potato (SP) grown continuously and in rotation with peanut (PE)-grain sorghum (GS) on yield, crop quality, and mixed nematode population densities of Meloidogyne arenaria, M. hapla, M. incognita, and Mesocriconema ornatum. Greater root-gall indices and damage by M. hapla and M. incognita occurred on potato than other crops. Most crop yields were higher and root-gall indices lower from fenamiphos-treated plots than untreated plots. The total yield of potato in the PO-SP and PO-SP-PE-GS sequences increased from 1983 to 1985 in plots infested with M. hapla or M. arenaria and M. incognita in combination and decreased in 1986 to 1987 when root-knot nematode populations shifted to M. incognita. The total yields of sweet potato in the PO-SP-PE-GS sequence were similar in 1983 and 1985, and declined each year in the PO-SP sequence as a consequence of M. incognita population density increase in the soil. Yield of peanut from soil infested with M. hapla increased 82% in fenamiphos-treated plots compared to untreated plots. Fenamiphos treatment increased yield of grain sorghum from 5% to 45% over untreated controls. The declining yields of potato and sweet potato observed with both the PO-SP and PO-SP-PE-GS sequences indicate that these crop systems should not be used longer than 3 years in soil infested with M. incognita, M. arenaria, or M. hapla. Under these conditions, these two cropping systems promote a population shift in favor of M. incognita, which is more damaging to potato and sweet potato than M. arenaria and M. hapla. 相似文献