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1.
Priscila Chaverri Gary J. Samuels 《Evolution; international journal of organic evolution》2013,67(10):2823-2837
Host jumps by microbial symbionts are often associated with bursts of species diversification driven by the exploitation of new adaptive zones. The objective of this study was to infer the evolution of habitat preference (decaying plants, soil, living fungi, and living plants), and nutrition mode (saprotrophy and mycoparasitism) in the fungal genus Trichoderma to elucidate possible interkingdom host jumps and shifts in ecology. Host and ecological role shifts were inferred by phylogenetic analyses and ancestral character reconstructions. The results support several interkingdom host jumps and also show that the preference for a particular habitat was gained or lost multiple times. Diversification analysis revealed that mycoparasitism is associated with accelerated speciation rates, which then suggests that this trait may be linked to the high number of species in Trichoderma. In this study it was also possible to infer the cryptic roles that endophytes or soil inhabitants play in their hosts by evaluating their closest relatives and determining their most recent ancestors. Findings from this study may have implications for understanding certain evolutionary processes such as species radiations in some hyperdiverse groups of fungi, and for more applied fields such as the discovery and development of novel biological control strategies. 相似文献
2.
Checchio Mirela Vantini de Cássia Alves Rita de Oliveira Kevein Ruas Moro Gustavo Vitti Santos Durvalina Maria Mathias dos Gratão Priscila Lupino 《Journal of plant research》2021,134(6):1279-1289
Journal of Plant Research - Salinity has become one of the major factors limiting agricultural production. In this regard, different cost-effective management strategies such as the use of plant... 相似文献
3.
Louisy Sanches dos Santos Camila Azevedo Antunes Cintia Silva dos Santos José Augusto Adler Pereira Priscila Soares Sabbadini Maria das Gra?as de Luna Vasco Azevedo Raphael Hirata Júnior Andreas Burkovski Lídia Maria Buarque de Oliveira Asad Ana Luíza Mattos-Guaraldi 《Memórias do Instituto Oswaldo Cruz》2015,110(5):662-668
Corynebacterium diphtheriae, the aetiologic agent of diphtheria,
also represents a global medical challenge because of the existence of invasive
strains as causative agents of systemic infections. Although tellurite
(TeO32-) is toxic to most microorganisms, TeO32--resistant
bacteria, including C. diphtheriae, exist in
nature. The presence of TeO32--resistance (TeR)
determinants in pathogenic bacteria might provide selective advantages in the natural
environment. In the present study, we investigated the role of the putative
TeR determinant (CDCE8392_813gene) in the virulence
attributes of diphtheria bacilli. The disruption of CDCE8392_0813 gene expression in
the LDCIC-L1 mutant increased susceptibility to TeO32- and reactive oxygen
species (hydrogen peroxide), but not to other antimicrobial agents. The LDCIC-L1
mutant also showed a decrease in both the lethality of Caenorhabditis elegans
and the survival inside of human epithelial cells compared to wild-type
strain. Conversely, the haemagglutinating activity and adherence to and formation of
biofilms on different abiotic surfaces were not regulated through the CDCE8392_0813
gene. In conclusion, the CDCE8392_813 gene contributes to the TeR and
pathogenic potential of C. diphtheriae. 相似文献
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De Almeida Salles Perroud AP Ashimine R De Castro GM Guimarães F Vieira KP Aparecida Vilella C Samico Cavalcanti TC De Lima Zollner R 《Cytokine》2006,36(3-4):123-133
Two variants of this Walker 256 tumor have been previously reported as Walker 256 A and variant AR. The variant A has more aggressive property than variant AR and can induce systemic effects such as anorexia, sodium and water retention, followed by weight loss and death. The mechanisms involved in enhancing tumor regression and progression in this model are still incompletely understood. In the present study, serum and spleen mononuclear cells and tumor cells from animals inoculated with variants A and AR, were isolated to investigate the TGF-beta, IL-12, IFN-gamma and TNF-alpha and relationship with anemia, weight of animals, weight of spleen, volume of tumor and osmotic fragility compared with controls inoculated with Ringer Lactate. Results demonstrate that the group inoculated with variant A, compared to variant AR, shows high levels of TGF-beta gene expression in both tumor tissue and spleen cells, no expression of IFN-gamma and a progressive and higher levels of IL-12 in tumor tissue without inflammatory infiltrate visualized by optical microscopy. These results suggest that the aggressively of variant A is relate to cytokine modulation, facilitating the growth and escape of tumor cells. Furthermore, IL-12 seems to be constitutively expressed in both tumor lineage A and AR. 相似文献
7.
Intra- and interspecific variation in trophic ecology of ‘predatory’ ants in the subfamily Ponerinae
Priscila E. Hanisch Kim Drager Wendy H. Yang Pablo L. Tubaro Andrew V. Suarez 《Ecological Entomology》2020,45(3):444-455
1. The characterisation of energy flow through communities is a primary goal of ecology. Furthermore, predator–prey interactions can influence both species abundance and community composition. The ant subfamily Ponerinae includes many predatory species that range from generalist insectivores to highly specialised hunters that target a single prey type. Given their high diversity and ubiquity in tropical ecosystems, measuring intra- and interspecific variation in their trophic ecology is essential for understanding the role of ants as predators of insect communities. 2. The stable isotopic composition of nitrogen of 22 species from the ant subfamily Ponerinae was measured, relative to plants and other predatory and herbivorous insects at two Atlantic Forest sites in Argentina. The study tested the general assumption that ponerine ants are all predatory, and examined intra- and interspecific variation in trophic ecology relative to habitat, body size and cytochrome c oxidase subunit 1 sequences (DNA barcoding). 3. Stable isotope analysis revealed that most ponerines occupy high trophic levels (primary and secondary predators), but some species overlapped with known insect herbivores. Species residing at low trophic levels were primarily arboreal and may rely heavily on nectar or other plant-based resources in their diet. In addition, larger species tend to occupy lower trophic positions than smaller species. 4. Although some of the species were divided into two or more genetic clusters by DNA barcoding analysis, these clusters did not correspond to intraspecific variation in trophic position; therefore, colony dietary flexibility most probably explains species that inhabit more than one trophic level. 相似文献
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9.
The bidentate complex of ATP with Cr(3+), CrATP, is a nucleotide analog that is known to inhibit the sarcoplasmic reticulum Ca(2+)-ATPase and the Na(+),K(+)-ATPase, so that these enzymes accumulate in a conformation with the transported ion (Ca(2+) and Na(+), respectively) occluded from the medium. Here, it is shown that CrATP is also an effective and irreversible inhibitor of the plasma membrane Ca(2+)-ATPase. The complex inhibited with similar efficiency the Ca(2+)-dependent ATPase and the phosphatase activities as well as the enzyme phosphorylation by ATP. The inhibition proceeded slowly (T(1/2)=30 min at 37 degrees C) with a K(i)=28+/-9 microM. The inclusion of ATP, ADP or AMPPNP in the inhibition medium effectively protected the enzyme against the inhibition, whereas ITP, which is not a PMCA substrate, did not. The rate of inhibition was strongly dependent on the presence of Mg(2+) but unaltered when Ca(2+) was replaced by EGTA. In spite of the similarities with the inhibition of other P-ATPases, no apparent Ca(2+) occlusion was detected concurrent with the inhibition by CrATP. In contrast, inhibition by the complex of La(3+) with ATP, LaATP, induced the accumulation of phosphoenzyme with a simultaneous occlusion of Ca(2+) at a ratio close to 1.5 mol/mol of phosphoenzyme. The results suggest that the transport of Ca(2+) promoted by the plasma membrane Ca(2+)-ATPase goes through an enzymatic phospho-intermediate that maintains Ca(2+) ions occluded from the media. This intermediate is stabilized by LaATP but not by CrATP. 相似文献
10.
The present study aimed to study the reaction conditions of grafting of acrylamide on xanthan gum. It was analyzed the influence of reaction conditions, mainly type of initiator activation, initiator concentration and initiator/acrylamide ratio, on graft parameters and copolymer properties. Potassium persulfate was employed as an initiator and heating or N,N,N',N'-tetramethylethylenediamine was used to activate the initiator. Reaction time and initiator concentration were varied and final values for grafting percentage and grafting efficiency were the same for both methods, whereas speed in reaching these values differs from one technique to another. We found that reaction time was inversely proportional to intrinsic viscosity, likely due to main chain degradation promoted by potassium persulfate (KPS); furthermore, the increasing in the KPS concentration lowers grafting percentage, acrylamide conversion and chain degradation, possibly as a result of O(2) formation at high KPS concentrations. 相似文献