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961.
Host‐associated divergence in the activity of digestive enzymes in two populations of the gypsy moth Lymantria dispar (Lepidoptera: Erebidae) 下载免费PDF全文
Jelica Lazarević Milena Janković‐Tomanić Uroš Savković Mirko Đorđević Slobodan Milanović Biljana Stojković 《Entomological Science》2017,20(1):189-194
The gypsy moth is a generalist insect pest with an extremely wide host range. Adaptive responses of digestive enzymes are important for the successful utilization of plant hosts that differ in the contents and ratios of constituent nutrients and allelochemicals. In the present study, we examined the responses of α‐amylase, trypsin, and leucine aminopeptidase to two tree hosts (suitable oak, Quercus cerris, and unsuitable locust tree, Robinia pseudoacacia) in the fourth, fifth, and sixth instars of gypsy moth larvae originating from oak and locust tree forest populations (hereafter assigned as Quercus and Robinia populations, respectively). Gypsy moths from the Robinia forest had been adapting to this unsuitable host for more than 40 generations. To test for population‐level host plant specialization, we applied a two‐population × two‐host experimental design. We compared the levels, developmental patterns, and plasticities of the activities of enzymes. The locust tree diet increased enzyme activity in the fourth instar and reduced activity in advanced instars of the Quercus larvae in comparison to the oak diet. These larvae also exhibited opposite developmental trajectories on the two hosts, i.e. activity increased on the oak diet and decreased on the locust tree diet with the progress of instar. Larvae of the Robinia population were characterized by reduced plasticity of enzyme activity and its developmental trajectories. In addition, elevated trypsin activity in response to an unsuitable host was observed in all instar larvae of the Robinia population, which demonstrated that Robinia larvae had an improved digestive performance than did Quercus larvae. 相似文献
962.
963.
Ectopic overexpression of porcine DGAT1 increases intramuscular fat content in mouse skeletal muscle
Ting Li Dequan Xu Bo Zuo Minggang Lei Yuanzhu Xiong Hongxing Chen Yanhong Zhou Xiaojie Wu 《Transgenic research》2013,22(1):187-194
The microsomal enzyme 1, 2-acyl CoA: diacylglyceroltransferase-1 (DGAT1) plays an important role in triglyceride storage in adipose tissue and expresses in skeletal muscle as well. The primary goal of the present study was to investigate the effect of porcine DGAT1 on intramuscular fat (IMF) content of transgenic mice produced by pronuclear microinjection with muscle specific promoter of porcine muscle creatine kinase (MCK). In normal chow-fed diet, 4 month-old male transgenic mice expressed more DGAT1, ACC1, UCP1, and FABP4 mRNAs and proteins in skeletal muscle than control mice by real-time PCR and western blot. No significant changes were detected for ACC2, CD36, ADRP, PPAR gamma and LPL. Triacylglycerol assay and soleus muscle sections showed overexpression of porcine DGAT1 in skeletal muscle increased intramyocellular triglyceride and percent of the total cell surface covered by lipid droplets. Thus, upregulation of porcine DGAT1 in skeletal muscle increases IMF content. The present study may further serve to develop transgenic pigs with higher IMF content and improved meat quality. 相似文献
964.
965.
Claudia Leoni Malgorzata Pietrzykowska Anett Z. Kiss Marjaana Suorsa Luigi R. Ceci Eva‐Mari Aro Stefan Jansson 《The Plant journal : for cell and molecular biology》2013,76(2):236-246
Light‐harvesting complex II (LHCII) contains three highly homologous chlorophyll‐a/b‐binding proteins (Lhcb1, Lhcb2 and Lhcb3), which can be assembled into both homo‐ and heterotrimers. Lhcb1 and Lhcb2 are reversibly phosphorylated by the action of STN7 kinase and PPH1/TAP38 phosphatase in the so‐called state‐transition process. We have developed antibodies that are specific for the phosphorylated forms of Lhcb1 and Lhcb2. We found that Lhcb2 is more rapidly phosphorylated than Lhcb1: 10 sec of ‘state 2 light’ results in Lhcb2 phosphorylation to 30% of the maximum level. Phosphorylated and non‐phosphorylated forms of the proteins showed no difference in electrophoretic mobility and dephosphorylation kinetics did not differ between the two proteins. In state 2, most of the phosphorylated forms of Lhcb1 and Lhcb2 were present in super‐ and mega‐complexes that comprised both photosystem (PS)I and PSII, and the state 2‐specific PSI–LHCII complex was highly enriched in the phosphorylated forms of Lhcb2. Our results imply distinct and specific roles for Lhcb1 and Lhcb2 in the regulation of photosynthetic light harvesting. 相似文献
966.
As climbing plants lack the capacity to hold themselves upright, they need to encounter a suitable host. Vines, lianas, and secondary hemiepiphytes need, therefore, an effective searching strategy. Various hypotheses have been put forward on searching strategies, including ‘skototropism’—growth toward darkness—and random searching. We studied host searching strategies of three secondary hemiepiphyte species belonging to the genus Heteropsis. We recorded information on the diameter distribution of host and evaluated whether these hosts were ‘suitable’, i.e., sufficiently tall for Heteropsis individuals to reach reproductive size. The diameter distribution of host trees bearing Heteropsis seedlings was similar to that of the trees in our study plots. Also, we found that 72–81 percent of the Heteropsis seedlings were present on unsuitable hosts (seedlings, saplings, herbs). These results suggest that Heteropsis seedlings search hosts in a random manner and not by skototropism. We found quite a distinct pattern for adult Heteropsis individuals, which predominantly occur on host trees bigger than 10 cm dbh. Host diameter distribution for Heteropsis adults differed significantly from that of the entire tree community. This difference suggests that Heteropsis individuals may change hosts if they are initially present on nonsuitable hosts. We observed that Heteropsis seedlings and juveniles on unsuitable hosts often produced vegetative shoots that searched for another host. In many cases, such shoots did not find a suitable host. For Heteropsis, our results suggest that host tree searching is a long‐term trial and error process that is governed by a random searching strategy. Abstract in Spanish is available in the online version of this article. 相似文献
967.
Zhe‐Long Jin Namgoong Suk Nam‐Hyung Kim 《Molecular reproduction and development》2019,86(9):1126-1137
Meiotic oocytes lack classic centrosomes; therefore, bipolar spindle assembly depends on the clustering of acentriolar microtubule‐organizing centers (MTOCs) into two poles. The bipolar spindle is an essential cellular component that ensures accurate chromosome segregation during anaphase. If the spindle does not form properly, it can result in aneuploidy or cell death. However, the molecular mechanism by which the bipolar spindle is established is not yet fully understood. Tumor suppressor p53‐binding protein 1 (TP53BP1) is known to mediate the DNA damage response. Several recent studies have indicated that TP53BP1 has noncanonical roles in processes, such as spindle formation; however, the role of TP53BP1 in oocyte meiosis is currently unclear. Our results show that TP53BP1 knockdown affects spindle bipolarity and chromatin alignment by altering MTOC stability during oocyte maturation. TP53BP1 was localized in the cytoplasm and displayed an irregular cloud pattern around the spindle/chromosome region. TP53BP1 was also required for the correct localization of MTOCs into the two spindle poles during pro‐meiosis I. TP53BP1 deletion altered the MTOC‐localized Aurora Kinase A. TP53BP1 knockdown caused the microtubules to detach from the kinetochores and increased the rate of aneuploidy. Taken together, our data show that TP53BP1 plays crucial roles in chromosome stability and spindle bipolarity during meiotic maturation. 相似文献
968.
Imprints of multiple glacial refugia in the Pyrenees revealed by phylogeography and palaeodistribution modelling of an endemic spider 下载免费PDF全文
Leticia Bidegaray‐Batista Alejandro Sánchez‐gracia Giulia Santulli Luigi Maiorano Antoine Guisan Alfried P. Vogler Miquel A. Arnedo 《Molecular ecology》2016,25(9):2046-2064
Mediterranean mountain ranges harbour highly endemic biota in islandlike habitats. Their topographic diversity offered the opportunity for mountain species to persist in refugial areas during episodes of major climatic change. We investigate the role of Quaternary climatic oscillations in shaping the demographic history and distribution ranges in the spider Harpactocrates ravastellus, endemic to the Pyrenees. Gene trees and multispecies coalescent analyses on mitochondrial and nuclear DNA sequences unveiled two distinct lineages with a hybrid zone around the northwestern area of the Catalan Pyrenees. The lineages were further supported by morphological differences. Climatic niche‐based species distribution models (SDMs) identified two lowland refugia at the western and eastern extremes of the mountain range, which would suggest secondary contact following postglacial expansion of populations from both refugia. Neutrality test and approximate Bayesian computation (ABC) analyses indicated that several local populations underwent severe bottlenecks followed by population expansions, which in combination with the deep population differentiation provided evidence for population survival during glacial periods in microrefugia across the mountain range, in addition to the main Atlantic and Mediterranean (western and eastern) refugia. This study sheds light on the complexities of Quaternary climatic oscillations in building up genetic diversity and local endemicity in the southern Europe mountain ranges. 相似文献
969.
Asymmetrical Resource Ownership Increases Owners’ and Reduces Non‐Owners’ Motivation to Fight in the Mangrove Rivulus,Kryptolebias marmoratus 下载免费PDF全文
Resource ownership often increases an individual's aggressiveness and its probability of defeating a competitor. Individuals contesting resource owners could therefore incur higher costs, making individuals reluctant to compete with owners. We tested the hypothesis that animals use asymmetry in resource ownership as a cue for contest costs and adjust contest decisions accordingly. Using a mangrove rivulus fish (Kryptolebias marmoratus), we staged (1) contests with a randomly assigned asymmetry in resource ownership (one fish was provided with a shelter) and (2) contests in which neither fish had a shelter. Owners that were in their shelters at the contest start showed a greater tendency to fight and won more contests than their intruder opponents; those outside the shelter at the start did not. Compared with fish in contests with no shelters at stake, shelter owners had a higher tendency to fight whether or not they were in their shelters at the start; intruders, however, had a lower tendency to fight only against owners that were inside the shelter at the start. These results demonstrate (1) that ownership status influences both owners’ and intruders’ contest decisions (and in opposite directions), producing a detectable ownership advantage and (2) that intruders required confirmation of their opponents’ ownership status before retreating without challenging them. Ownership status per se is therefore important to the fish's contest decisions. 相似文献
970.