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111.
Plants respond to grazing by herbivorous insects by emitting a range of volatile organic compounds, which attract parasitoids
to their insect hosts. However, a positive outcome for the host plant is a necessary precondition for making the attraction
beneficial or even adaptive. Parasitoids benefit plants by killing herbivorous insects, thus reducing future herbivore pressure,
but also by curtailing the feeding intensity of the still living, parasitised host. In this study, the effect of parasitism
on food consumption of the 5th instar larvae of the autumnal moth (Epirrita autumnata) was examined under laboratory conditions. Daily food consumption, as well as the duration of the 5th instar, was measured
for both parasitised and non-parasitised larvae. The results showed that parasitism by the solitary endoparasitoid Zele deceptor not only reduced leaf consumption significantly but also hastened the onset of pupation in autumnal moth larvae. On the basis
of the results, an empirical model was derived to assess the affects on the scale of the whole tree. The model suggests that
parasitoids might protect the tree from total defoliation at least at intermediate larval densities. Consequently, a potential
for plant–parasitoid chemical signalling appears to exist, which seems to benefit the mountain birch (Betula pubescens ssp. czerepanovii) by reducing the overall intensity of herbivore defoliation due to parasitism by this hymenopteran parasitoid. 相似文献
112.
Late Triassic sedimentary evolution of Slovenian Basin (eastern Southern Alps): description and correlation of the Slatnik Formation 总被引:1,自引:0,他引:1
Successions of the Slovenian Basin structurally belong to the easternmost Southern Alps. During the Late Triassic, they were
part of the Adriatic continental margin. Norian–Rhaetian successions of the Slovenian Basin are characterized mainly by dolomite
of the Bača Dolomite Formation. However, in the northern part of the basin, Late Triassic limestone is preserved above Bača
Dolomite Formation and is formalized as the Slatnik Formation. It is composed of hemipelagic limestone alternating with resedimented
limestones. The succession documents an upward progradation of the slope environment composed of three high-frequency cycles.
Most prominent progradation is referred to the second, i.e., Early Rhaetian cycle. The Slatnik Formation ends with thin-bedded
hemipelagic limestone that records the end-Triassic productivity crisis, or rapid sea-level fall. The overlying resedimented
limestones of the Early Jurassic Krikov Formation, document the recovery of production and shedding from the adjacent carbonate
platform. 相似文献
113.
The functional activities of proteins are closely related to their molecular structure and understanding their structure-function relationships remains one of the intriguing problems of molecular biology. We investigated structural changes in 17beta-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17beta-HSDcl) induced by pH, temperature, salt, urea, guanidine hydrochloride, and coenzyme NADPH binding. At 25 degrees C and within the relatively narrow pH range of 7.0-9.0, 17beta-HSDcl exists in its native conformation as a dimer. This native conformation is thermally stable up to 40 degrees C in this pH range. At 25 degrees C and pH 2.0 in the presence of 150-300 mM NaCl, 17beta-HSDcl forms soluble aggregates enriched in alpha-helical and beta-sheet structures. At higher temperatures and NaCl concentrations, these soluble aggregates start to precipitate. The denaturants urea and guanidine hydrochloride unfold 17beta-HSDcl at concentrations of 1.2 and 0.4 M, respectively. Binding of the coenzyme NADPH to 17beta-HSDcl causes local structural changes that do not significantly affect the thermal stability of this protein. 相似文献
114.
Sova M Perdih A Kotnik M Kristan K Rizner TL Solmajer T Gobec S 《Bioorganic & medicinal chemistry》2006,14(22):7404-7418
The 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) modulate the biological potency of estrogens and androgens by interconversion of inactive 17-keto-steroids and their active 17beta-hydroxy- counterparts. We have shown previously that flavonoids are potentially useful lead compounds for developing inhibitors of 17beta-HSDs. In this paper, we describe the synthesis and biochemical evaluation of structurally analogous inhibitors, the trans-cinnamic acid esters and related compounds. Additionally, quantitative structure-activity relationship (QSAR) and modelling studies were performed to rationalize the results and to suggest further optimization. The results stress the importance of a hydrogen bond with Asn154 and hydrophobic interactions with the aromatic side chain of Tyr212 for optimal molecular recognition. 相似文献
115.
Marvin E. Tanenbaum Tea Vallenius Erica F. Geers Lois Greene Tomi P. Mäkelä Rene H. Medema 《Chromosoma》2010,119(4):415-424
During mitosis, all chromosomes must attach to microtubules of the mitotic spindle to ensure correct chromosome segregation.
Microtubule attachment occurs at specialized structures at the centromeric region of chromosomes, called kinetochores. These
kinetochores can generate microtubule attachments through capture of centrosome-derived microtubules, but in addition, they
can generate microtubules themselves, which are subsequently integrated with centrosome-derived microtubules to form the mitotic
spindle. Here, we have performed a large scale RNAi screen and identify cyclin G-associated kinase (GAK) as a novel regulator
of microtubule generation at kinetochores/chromatin. This function of GAK requires its C-terminal J-domain, which is essential
for clathrin recycling from endocytic vesicles. Consistently, cells lacking GAK show strongly reduced levels of clathrin on
the mitotic spindle, and reduction of clathrin levels also inhibits microtubule generation at kinetochores/chromosomes. Finally,
we present evidence that association of clathrin with the spindle is promoted by a signal coming from the chromosomes. These
results identify a role for GAK and clathrin in microtubule outgrowth from kinetochores/chromosomes and suggest that GAK acts
through clathrin to control microtubule outgrowth around chromosomes. 相似文献
116.
Caljkusić-Mance T Kovacević D Novak-Stroligo M Alpeza-Dunato Z 《Collegium antropologicum》2010,34(Z2):109-111
The aim of this study is to show what part of our County has the most population with age-related macular degeneration (ARMD) and how some types frequently appear in same parts. The County includes 3 different geographic areas: Gorski Kotar, Coast and Islands. ARMD is the leading cause of visual impairment and blindness in developed countries. There are two categories of ARMD: atrophic or "dry" ARMD and exudative or"wet" ARMD. Our epidemiological study group includes 60 patients (33 females, 27 males) with both types of ARMD and they mostly spent their life times in our County. Patients were examined and treated in our Clinic during 2008 and 2009. We also examined which contribution factor (age, genetics, UV-exposure, diet, iris and macular pigment) is more common and found a links with occupation, residence and habits. Our study shows that ARMD in our County is most frequent in interval of 61-80 years. Incidence of ARMD is mild increased in female (55%). Significant incidence of ARMD is connected with patients who work outdoor more than 5 hours daily (70 %). There were no significant difference between patients in different areas[-Gorski Kotar and Coast (p = 0.9260), Gorshi Kotar and Islands (p = 0.8382) and Coast and Islands (p = 0.8546) connected with occupations. Regions Coast and Islands had more cases of ARMD than Gorski Kotar, but in Gorski Kotar patients had greater percent of "wet" type. Difference is statistically significant between areas Gorski Kotar and Islands (chi2 = 4.675, p = 0.0306). Also, there were statistically significant difference in nutrition between Gorski Kotar and Islands (chi2 = 4.17, p = 0.0411). Incidence of ARMD is related with less iris and macular pigment--47 patients (77%). There was an increased risk for exudative type in Trs?e and Cabar in Gorski Kotar 相似文献
117.
Chris J. Watson Isaac Tea Eoin O'Connell Nadezhda Glezeva Shuaiwei Zhou Stephanie James Joe Gallagher James Snider James L. Januzzi Mark T. Ledwidge Ken M. McDonald 《Journal of cellular and molecular medicine》2020,24(11):6495-6499
Biomarker-based preventative and monitoring strategies are increasingly used for risk stratification in cardiovascular (CV) disease. The aim of this study was to investigate the utility of longitudinal change in B-type natriuretic peptide (BNP) and sST2 concentrations for predicting incident major adverse CV events (MACE) (heart failure, myocardial infarction, arrhythmia, stroke/transient ischaemic attack and CV death) in asymptomatic community-based patients with risk factors but without prevalent MACE at enrolment. The study population consisted of 282 patients selected from the longitudinal STOP-HF study of asymptomatic patients with risk factors for development of MACE. Fifty-two of these patients developed a MACE. The study was run in two phases comprising of an initial investigative cohort (n = 195), and a subsequent 2:1 (No MACE: MACE) propensity matched verification cohort (n = 87). BNP and sST2 were quantified in all patients at two time points a median of 2.5 years apart. Results highlighted that longitudinal change in sST2 was a statistically significant predictor of incident MACE, (AUC 0.60). A one-unit increment in sST2 change from baseline to follow up corresponded to approximately 7.99% increase in the rate of one or more incident MACE, independent of the baseline or follow-up concentration. In contrast, longitudinal change value of BNP was not associated with MACE. In conclusion, longitudinal change in sST2 but not BNP was associated with incident MACE in asymptomatic, initially event-free patients in the community. Further work is required to evaluate the clinical utility of change in sST2 in risk prediction and event monitoring in this setting. 相似文献
118.
François P. Bi Koffi Kouamé Virginie Silvestre Gustave Bedi Denis Loquet Richard J. Robins Illa Tea 《Phytochemistry letters》2013,6(2):253-256
Leptoderris fasciculata (Benth.) Dunn is a woody liana that grows in the tropical zone of West Africa, where it is exploited in traditional medicine for a number of uses. In the south-eastern Ivory Coast, it is applied to stop bleeding in women after childbirth or in cases of menorrhagia. The phytochemistry of this plant has received little previous attention. We report the isolation of 4′,5,6,7-tetramethoxyisoflavone and dihydrochalcone, new as natural products, together with 10 known compounds from the leaves of L. fasciculata collected in the Ivory Coast. 相似文献
119.
Connie Jackaman Hannah G. Radley‐Crabb Zoe Soffe Tea Shavlakadze Miranda D. Grounds Delia J. Nelson 《Aging cell》2013,12(3):345-357
Changes to innate cells, such as macrophages and myeloid‐derived suppressor cells (MDSCs), during aging in healthy or tumor‐bearing hosts are not well understood. We compared macrophage subpopulations and MDSCs from healthy young (6–8 weeks) C57BL/6J mice to those from healthy geriatric (24–28 months) mice. Spleens, lymph nodes, and bone marrow of geriatric hosts contained significantly more M2 macrophages and MDSCs than their younger counterparts. Peritoneal macrophages from geriatric, but not young, mice co‐expressed CD40 and CX3CR1 that are usually mutually exclusively expressed by M1 or M2 macrophages. Nonetheless, macrophages from geriatric mice responded to M1 or M2 stimuli similarly to macrophages from young mice, although they secreted higher levels of TGF‐β in response to IL‐4. We mimicked conditions that may occur within tumors by exposing macrophages from young vs. geriatric mice to mesothelioma or lung carcinoma tumor cell–derived supernatants. While both supernatants skewed macrophages toward the M2‐phenotype regardless of age, only geriatric‐derived macrophages produced IL‐4, suggesting a more immunosuppressive tumor microenvironment will be established in the elderly. Both geriatric‐ and young‐derived macrophages induced allogeneic T‐cell proliferation, regardless of the stimuli used, including tumor supernatant. However, only macrophages from young mice induced T‐cell IFN‐γ production. We examined the potential of an IL‐2/agonist anti‐CD40 antibody immunotherapy that eradicates large tumors in young hosts to activate macrophages from geriatric mice. IL‐2‐/CD40‐activated macrophages rescued T‐cell production of IFN‐γ in geriatric mice. Therefore, targeting macrophages with IL‐2/anti‐CD40 antibody may improve innate and T‐cell immunity in aging hosts. 相似文献
120.
Frédérique Courant Arnaud Martzolff Graziella Rabin Jean-Philippe Antignac Bruno Le Bizec Patrick Giraudeau Illa Tea Serge Akoka Aurélie Couzinet Guillaume Cogne Dominique Grizeau Olivier Gonçalves 《Metabolomics : Official journal of the Metabolomic Society》2013,9(6):1286-1300
Microalgae appear to be one of the most promising sustainable resources as alternative crops for the production of renewable transport fuel. The exploitation of this bioresource requires, however, a fine monitoring of the culture conditions, for example by using more relevant control variables than usual macroscopic indicators (biomass or pigment estimation). In this proof of concept study, we propose to search potential biomarkers of progressive nitrogen regime culture conditions using an untargeted metabolomic approach based on LC-HRMS combined to a non-invasive analysis based on FTIR spectroscopy. One microalgae model was investigated i.e. Chlamydomonas reinhardtii to characterize the effect of progressive nitrogen regime in batch culture conditions on its metabolome. FTIR allowed assessing the intracellular macrometabolic perturbations, highlighting the over-accumulation of carbohydrates. LC-HRMS complemented the macromolecular information by revealing the dependence of microalgae metabotypes on nitrogen regime conditions tested for cells culture. Patterns of significantly modulated metabolites were also detected during those slight contrasted nitrogen regimes and interesting features were structurally elucidated. This included metabolites belonging to the pantothenate, branched chain and aromatic amino acids pathways. In the last step of this proof of concept study, amino acid targets proposed by metabolomic investigations were assessed on nitrogen-limited continuous culture on photobioreactors. This was performed to test the validity of proposed targets in real small-scale industrial production conditions. Results were very encouraging and suggested the possibility of using potentially relevant metabolites as intracellular biomarkers only (tryptophan) or as both intra and extracellular biomarkers (e.g. 2-methylbutyric acid and ketoleucine). 相似文献