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941.
Raquel Mendes Vera L. Nunes Eduardo Marabuto Gonçalo J. Costa Sara E. Silva Octávio S. Paulo Paula C. Simões 《Journal of evolutionary biology》2023,36(2):461-479
Divergence in acoustic signals may have a crucial role in the speciation process of animals that rely on sound for intra-specific recognition and mate attraction. The acoustic adaptation hypothesis (AAH) postulates that signals should diverge according to the physical properties of the signalling environment. To be efficient, signals should maximize transmission and decrease degradation. To test which drivers of divergence exert the most influence in a speciose group of insects, we used a phylogenetic approach to the evolution of acoustic signals in the cicada genus Tettigettalna, investigating the relationship between acoustic traits (and their mode of evolution) and body size, climate and micro-/macro-habitat usage. Different traits showed different evolutionary paths. While acoustic divergence was generally independent of phylogenetic history, some temporal variables’ divergence was associated with genetic drift. We found support for ecological adaptation at the temporal but not the spectral level. Temporal patterns are correlated with micro- and macro-habitat usage and temperature stochasticity in ways that run against the AAH predictions, degrading signals more easily. These traits are likely to have evolved as an anti-predator strategy in conspicuous environments and low-density populations. Our results support a role of ecological selection, not excluding a likely role of sexual selection in the evolution of Tettigettalna calling songs, which should be further investigated in an integrative approach. 相似文献
942.
Koehler Andréa D. Rossi Mônica L. Carneiro Vera T. C. Cabral Glaucia B. Martinelli Adriana P. Dusi Diva M. A. 《Protoplasma》2023,260(2):571-587
Protoplasma - Brachiaria, a genus from the Poaceae family, is largely cultivated as forage in Brazil. Among the most cultivated varieties of Brachiaria spp., B. brizantha cv. Marandu (syn. Urochloa... 相似文献
943.
944.
Pfeifer Karin; Haasemann Martina; Gamulin Vera; Bretting Hagen; Fahrenholz Falk; Mller Werner E.G. 《Glycobiology》1993,3(2):179-184
The marine sponge Geodia cydonium contains several lectins.The main component, called lectin-1, is composed of three tofour identical subunits. The subunits of the lectins were clonedfrom a cDNA library; two clones were obtained. From the deducedaa sequence of one clone, LECT-1, a mol. wt of 15 313 Da iscalculated; this value is in good agreement with mass spectrometricanalysis of 15 453 25 Da. The sequence of another clone, LECT-2,was analysed and the aa sequence was deduced (15 433 Da). Thetwo subunits have a framework sequence of 38 conserved aa whichare characteristic for the carbohydrate-binding site of vertebrateS-type lectins. Clustering of lectin sequences of various speciesfollowing their pairwise comparison establishes a dendrogram,which reveals that the sponge lectin could be considered asthe ancestor for vertebrate S-type lectins. Geodia cydonium lectin sponges S-type lectin 相似文献
945.
Abstract: We studied the effect of α-latrotoxin (αLTX) on [14C]acetylcholine ([14C]ACh) release, intracellular Ca2+ concentration ([Ca2+]i), plasma membrane potential, and high-affinity choline uptake of synaptosomes isolated from guinea pig cortex. αLTX (10?10-10?8M) caused an elevation of the [Ca2+]i as detected by Fura 2 fluorescence and evoked [14C]ACh efflux. Two components in the action of the toxin were distinguished: one that required the presence of Na+ in the external medium and another that did not. Displacement of Na+ by sucrose or N-methylglucamine in the medium considerably decreased the elevation of [Ca2+]i and [14C]ACh release by αLTX. The Na+-dependent component of the αLTX action was obvious in the inhibition of the high-affinity choline uptake of synaptosomes. Some of the toxin action on both [Ca2+]i and [14C]ACh release remained in the absence of Na+. Both the Na+-dependent and the Na+-independent components of the αLTX-evoked [14C]ACh release partly required the presence of either Mg2+ or Ca2+. The nonneurotransmitter [14C]choline was released along with [14C]ACh, but this release did not depend on the presence of either Na+ or Ca2+, indicating nonspecific leakage through the plasma membrane. We conclude that there are two factors in the release of ACh from synaptosomes caused by the toxin: (1) cation-dependent ACh release, which is related to (a) Na+-dependent divalent cation entry and (b) Na+-independent divalent cation entry, and (2) nonspecific Na+- and divalent cation-independent leakage. 相似文献
946.
The ultrastructure of vegetative cells and spores of Bacillus pulvifaciens was studied by CTEM and SEM methods. The vegetative cells are rods, 1.6–4.5 m long and 0.4–0.6 m wide, exhibiting typical ultrastructural features of Gram-positive bacteria. The spores are of ellipsoidal shape, 0.6×1.2 m in size, with six longitudinal ribs reaching up to 130 nm in height. There are satelite ribs on both sides of the longitudinal ribs, reaching up to 20 nm in height. Between the longitudinal ribs, additional transversal ribs were observed in SEM. A special tubular layer, separating the outer and inner coat of the spores, was revealed in ultrathin sections. This layer seems to be a typical ultrastructural feature of Bacillus pulvifaciens spores. 相似文献
947.
948.
Patterns of systemically induced resistance (SIR) in Eastern Cottonwood, Populus deltoides, measured by reduced feeding of the leaf-chewing beetle, Plagiodera versicolora, were shown to be directly related to the distribution of the plant vasculature. Mechanical damage to single leaves resulted in SIR in non-adjacent, orthostichous leaves (vertically aligned on the stem) with direct vascular connections, both up and down the shoot; but no SIR in adjacent, non-orthostichous leaves with less direct vascular connections. The control that the plant vasculature exerts over signal distribution following wounding can therefore be used to predict SIR patterns, explain variation in the distribution of SIR, and relate this ecologically important phenomenon to biochemical processes of systemic gene expression and biochemical resistance mechanisms. 相似文献
949.
950.
Ameli Kirse Sarah J. Bourlat Kathrin Langen Björn Zapke Vera M. A. Zizka 《Molecular ecology resources》2023,23(1):92-105
DNA metabarcoding is routinely used for biodiversity assessment, in particular targeting highly diverse groups for which limited taxonomic expertise is available. Various protocols are currently in use, although standardization is key to its application in large-scale monitoring. DNA metabarcoding of arthropod bulk samples can be conducted either destructively from sample tissue, or nondestructively from sample fixative or lysis buffer. Nondestructive methods are highly desirable for the preservation of sample integrity but have yet to be experimentally evaluated in detail. Here, we compare diversity estimates from 14 size-sorted Malaise trap samples processed consecutively with three nondestructive approaches (one using fixative ethanol and two using lysis buffers) and one destructive approach (using homogenized tissue). Extraction from commercial lysis buffer yielded comparable species richness and high overlap in species composition to the ground tissue extracts. A significantly divergent community was detected from preservative ethanol-based DNA extraction. No consistent trend in species richness was found with increasing incubation time in lysis buffer. These results indicate that nondestructive DNA extraction from incubation in lysis buffer could provide a comparable alternative to destructive approaches with the added advantage of preserving the specimens for postmetabarcoding taxonomic work but at a higher cost per sample. 相似文献