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A survey for phytoplasma diseases was conducted in a sweet and sour cherry germplasm collection and in cherry orchards within the Czech Republic during 2014–2015. Phytoplasmas were detected in 21 symptomatic trees. Multiple infections of cherry trees by diverse phytoplasmas of 16SrI and 16SrX groups and 16SrI‐A, 16SrI‐B, 16SrI‐L, 16SrX‐A subgroups were detected by restriction fragment length polymorphism (RFLP). Nevertheless, phylogenetic analysis placed subgroups 16SrI‐B and 16SrI‐L inseparable together onto one branch of phylogenetic tree. This is the first report of subgroups 16SrI‐A and 16SrI‐L in Prunus spp., and subgroup 16SrX‐A in sour cherry trees. Additionally, novel RFLP profiles for 16SrI‐A and 16SrI‐B‐related phytoplasmas were found in cherry samples. Phytoplasmas with these novel profiles belong, however, to their respective 16SrI‐A or 16SrI‐B phylogenetic clades.  相似文献   

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SYNOPSIS. An electron microscope study was made of the “cyst-like bodies” (CLBs) previously described in cultures of Trypanosoma conorhini. It is again suggested that CLBs are a process of reproduction which involves fusion of epimastigotes, repeated divisions of DNA-containing organelles and organization of daughter epimastigotes that, after being completely formed, may be found free within the large central “vacuole” of the CLB. This “vacuole,” it is now evident, results from the fused and muchdilated flagellar reservoirs of parent epimastigotes. Our interpretation of the CLBs and their possible genetic significance are discussed.  相似文献   

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The fossil evidence of the “robust” australopithecines is reviewed with an emphasis on the taxonomic divisions and evolutionary relationships among this group of hominids. The hypodigms of A. robustus, A. crassidens and A. boisei are described, and the significance of morphological variation within and between these species is assessed. Phylogenetic relationships among the “robust” australopithecines are examined using maximum parsimony analysis, and evolutionary scenarios are evaluated in the light of recent discoveries in East Africa.  相似文献   

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In this review, we focus on strategies for designing functional nano gene carriers, as well as choosing therapeutic genes targeting the tumor microenvironment. Gene mutations have a great impact on the occurrence of cancer. Thus, gene therapy plays a major role in cancer therapy and has the potential to cure cancer. Well‐designed gene therapy largely relies on effective gene carriers, which can be divided into viral carriers and non‐viral carriers. A gene carrier delivers functional genes to their intracellular target and avoids nucleic acids being degraded by nucleases in the serum. Most conventional cancer gene therapies only target cancer cells and do not appear to be sufficintly efficient to pass clinical trials. Accumulating evidence has shown that extending the therapeutic strategies to the tumor microenvironment, rather than the tumor cell itself, can allow more options for achieving robust anti‐cancer efficiency. In addition, unusual features between tumor microenvironment and normal tissues, such as a lower pH, higher glutathione and reactive oxygen species concentrations, and overexpression of some enzymes, facilitate the design of smart stimuli‐responsive gene carriers regulated by the tumor microenvironment. These carriers interact with nucleic acids and then form stable nanoparticles under physiological conditions. By regulation of the tumor microenvironment, stimuli‐responsive gene carriers are able to change their properties and achieve high gene delivery efficiency. Considering the tumor microenvironment as the “regulator” and “target” when designing gene carriers and choosing therapeutic genes shows significant benefit with respect to improving the accuracy and efficiency of cancer gene therapy.  相似文献   

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The United Nations (UN) Convention on the Rights of Persons with Disabilities (CRPD) is the most up‐to‐date international legal instrument concerning the rights of persons with disabilities. Such persons are taken to include those with serious mental disorders. According to an authoritative interpretation of a crucial Article (Article 12 ‐ Equal recognition before the law) by the UN CRPD Committee, involuntary detention and treatment of people with mental health disabilities are prohibited under the Convention. Both conventional mental health law and “capacity‐based” law are deemed to violate the Convention. However, some other UN bodies are not in full agreement (for example, the UN Human Rights Committee and the Subcommittee on Prevention of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment), while others are less explicitly absolutist (for example, the Human Rights Council). Furthermore, strong criticisms of the position of the CRPD Committee have been mounted from a number of academic quarters. These criticisms center on whether the role of a person's ability to make a decision can be ignored, no matter the circumstances. Much of the above debate turns on the concept of “legal capacity” and the now often‐repeated precept that one must always respect the “will and preferences” of the person with a disability. However, “will and preferences” remains undefined. In this paper, I offer an analysis of “will and preferences” that can clarify interventions that may be acceptable or non‐acceptable under the terms of the UN Convention.  相似文献   

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The transdiagnostic expression of psychotic experiences in common mental disorder (anxiety/depression/substance use disorder) is associated with a poorer prognosis, and a small minority of people may indeed develop a clinical picture that meets criteria for schizophrenia. However, it appears neither useful nor valid to observe early states of multidimensional psychopathology in young people through the “schizo”‐prism, and apply misleadingly simple, unnecessary and inefficient binary concepts of “risk” and “transition”. A review of the “ultra‐high risk” (UHR) or “clinical high risk” (CHR) literature indicates that UHR/CHR samples are highly heterogeneous and represent individuals diagnosed with common mental disorder (anxiety/depression/substance use disorder) and a degree of psychotic experiences. Epidemiological research has shown that psychotic experiences are a (possibly non‐causal) marker of the severity of multidimensional psychopathology, driving poor outcome, yet notions of “risk” and “transition” in UHR/CHR research are restrictively defined on the basis of positive psychotic phenomena alone, ignoring how baseline differences in multidimensional psychopathology may differentially impact course and outcome. The concepts of “risk” and “transition” in UHR/CHR research are measured on the same dimensional scale, yet are used to produce artificial diagnostic shifts. In fact, “transition” in UHR/CHR research occurs mainly as a function of variable sample enrichment strategies rather than the UHR/CHR “criteria” themselves. Furthermore, transition rates in UHR/CHR research are inflated as they do not exclude false positives associated with the natural fluctuation of dimensional expression of psychosis. Biological associations with “transition” thus likely represent false positive findings, as was the initial claim of strong effects of omega‐3 polyunsatured fatty acids in UHR samples. A large body of UHR/CHR intervention research has focused on the questionable outcome of “transition”, which shows lack of correlation with functional outcome. It may be more productive to consider the full range of person‐specific psychopathology in all young individuals who seek help for mental health problems, instead of “policing” youngsters for the transdiagnostic dimension of psychosis. Instead of the relatively inefficient medical high‐risk approach, a public health perspective, focusing on improved access to a low‐stigma, high‐hope, small scale and youth‐specific environment with acceptable language and interventions may represent a more useful and efficient strategy.  相似文献   

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Horseshoe crabs' exceptional morphological conservatism over the past 150 My has led to their reputation as “living fossils,” but also has served to obscure phylogenetic relationships within the complex. Here we employ nucleotide sequences from two mitochondrial genes to assess molecular evolutionary rates and patterns among all extant horseshoe crab species. The American species Limulus polyphemus proved to be the sister taxon to a clade composed of the Asiatic species Tachypleus gigas, T. tridentatus, and Carcinoscorpius rotundicauda, whose relationships inter se were not resolved definitively. Both absolute and relative rate tests suggest a moderate slowdown in sequence evolution in horseshoe crabs. Nonetheless, dates of the lineage separations remain uncertain primarily because of reservations about molecular-clock calibrations resulting from large rate variances at examined loci across Arthropods and other animal lineages, as inferred in this and prior studies. Thus, ironically, separation dates as estimated by molecular evidence in general may remain most insecure in taxonomic groups for which such information is needed most—those lacking strong biogeographic or fossil benchmarks for internal-clock calibrations. In any event, the current results show that large numbers of molecular characters distinguish even these most morphologically conservative of organisms. Furthermore, comparisons against previously published mitochondrial sequence data in the morphologically dynamic hermit crab–king crab complex demonstrates that striking heterogeneity in levels of morphotypic differentiation can characterize Arthropod lineages at similar magnitudes of molecular divergence.  相似文献   

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The fine structure of Amoeba discoides, Amoeba dubia, and Amoeba amazonas was studied and compared with that of Amoeba proteus. The different kinds of amebas showed general similarities but differed in the ultrastructural details of their organelles. With respect to fine structure, A. discoides was indistinguishable from A. proteus, while both A. dubia and A. amazonas had distinctive features. The nuclei of all had a prominent honeycomb-like fibrous lamina, but A. dubia differed from the others in the distribution of nucleoli within the nucleus. The mitochondria of A. amazonas were unusual in having a variable pattern of cristae, some being plate-like and others tubular. Golgi bodies in A. amazonas had a greater proportion of vesicles and a smaller number of cisternae than those of the others, while Golgi bodies in A. dubia had highly flattened cisternae without a lining of filamentous material such as is found in the other types. The plasma membrane of A. dubia also lacked the prominent filamentous cell coat common to A. proteus and other amebas. The relation between the Golgi apparatus and the cell coat and the significance of the degree of development of the cell coat for pinocytosis and other phenomena is considered. The experimental use of these cells, including the formation of hybrids by nuclear transplantation is discussed.  相似文献   

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Eating behavior can be influenced by the rewarding value of food, i.e., “liking” and “wanting.” The objective of this study was to assess in normal‐weight dietary restrained (NR) vs. unrestrained (NU) eaters how rewarding value of food is affected by satiety, and by eating a nonhealthy perceived, dessert‐specific food vs. a healthy perceived, neutral food (chocolate mousse vs. cottage cheese). Subjects (24NR age = 25.0 ± 8.2 years, BMI = 22.3 ± 2.1 kg/m2; 26NU age = 24.8 ± 8.0 years, BMI = 22.1 ± 1.7 kg/m2) came to the university twice, fasted (randomized crossover design). Per test‐session “liking” and “wanting” for 72 items divided in six categories (bread, filling, drinks, dessert, sweets, stationery (placebo)) was measured, before and after consumption of chocolate mousse/cottage cheese, matched for energy content (5.6 kJ/g) and individual daily energy requirements (10%). Chocolate mousse was liked more than cottage cheese (P < 0.05). After consumption of chocolate mousse or cottage cheese, appetite and “liking” vs. placebo were decreased in NR and NU (P < 0.03), whereas “wanting” was only decreased in NR vs. NU (P ≤ 0.01). In NR vs. NU “wanting” was specifically decreased after chocolate mousse vs. cottage cheese; this decrease concerned especially “wanting” for bread and filling (P < 0.05). To conclude, despite similar decreases in appetite and “liking” after a meal in NR and NU, NR decrease “wanting” in contrast to NU. NR decrease “wanting” specifically for a nonhealthy perceived, “delicious,” dessert‐specific food vs. a nutritional identical, yet healthy perceived, slightly less “delicious,” “neutral” food. A healthy perceived food may thus impose greater risk for control of energy intake in NR.  相似文献   

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New neurons are added to two bilateral clusters of neurons in crayfish brain throughout their lives. These interneurons are associated with the olfactory and accessory lobes, areas of the brain that receive primary olfactory information and higher order inputs from the visual and tactile receptor systems. The rate of cell proliferation in these four clusters, revealed by BrdU labeling, is sensitive to the living conditions of the animals: individuals isolated in small spaces (impoverished condition) exhibit a lower rate of cell proliferation in comparison to their siblings living together in larger areas (enriched condition), although both groups were fed to satiation. Reduction in the rate of proliferation can be measured 1 to 2 weeks after the animals are subjected to the impoverished condition. Counts of the labeled neurons that survive after 4 weeks of subjection to the two conditions show that fewer new neurons survive in the brains of animals that have lived for 2 weeks in the impoverished condition in comparison to their siblings living in the enriched conditions. Factors such as surface area, depth of water, and social interaction can all play a role in determining both the rate of new neuron production and the incorporation of the new neurons into the brain of freshwater crayfish. The results indicate a high degree of neuronal plasticity in the crayfish brain that is highly sensitive to the conditions under which the animals are kept. © 2000 John Wiley & Sons, Inc. J Neurobiol 45: 215–226, 2000  相似文献   

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Restoration is important in urban areas where habitat destruction is greatest. It incorporates many levels of intervention, with creation of new habitat the most extreme form. Most research on habitat creation has been terrestrial, or in marine habitats dominated by large structuring biota, such as mangroves. Intertidal boulder‐fields in urban areas are vulnerable to disturbances and habitat loss, which adversely affect numerous habitat specialists. This study describes experiments in which quarried stones were used to create new habitat outside natural boulder‐fields as a practical approach to restoring habitat. Colonization by specialist fauna and by common algae and invertebrates was measured for a year after deployment. Despite sessile assemblages on new boulders differing from those on natural boulders, common and rare animals rapidly colonized the new habitat. There was no clear succession, but colonization was variable and patchy at all scales examined, although diversities and abundances of some species in this novel habitat matched those of natural boulders within a few months. Rare and common animals generally colonized the new habitat as adults moving in from surrounding areas. Creating new boulder‐fields using quarried rocks is a successful approach to restoration and conservation of fauna where natural boulder‐fields are threatened.  相似文献   

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Understanding changes in biodiversity requires the implementation of monitoring programs encompassing different dimensions of biodiversity through varying sampling techniques. In this work, fish assemblages associated with the “outer” and “inner” sides of four marinas, two at the Canary Islands and two at southern Portugal, were investigated using three complementary sampling techniques: underwater visual censuses (UVCs), baited cameras (BCs), and fish traps (FTs). We firstly investigated the complementarity of these sampling methods to describe species composition. Then, we investigated differences in taxonomic (TD), phylogenetic (PD) and functional diversity (FD) between sides of the marinas according to each sampling method. Finally, we explored the applicability/reproducibility of each sampling technique to characterize fish assemblages according to these metrics of diversity. UVCs and BCs provided complementary information, in terms of the number and abundances of species, while FTs sampled a particular assemblage. Patterns of TD, PD, and FD between sides of the marinas varied depending on the sampling method. UVC was the most cost‐efficient technique, in terms of personnel hours, and it is recommended for local studies. However, for large‐scale studies, BCs are recommended, as it covers greater spatio‐temporal scales by a lower cost. Our study highlights the need to implement complementary sampling techniques to monitor ecological change, at various dimensions of biodiversity. The results presented here will be useful for optimizing future monitoring programs.  相似文献   

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SYNOPSIS. Relatively high concentrations (10–100 μM) of chromate, selenate, and vanadate ions accelerated growth of Leishmania tarentolae in a chemically defined medium containing taurine as the sole sulfur source. These ions also enhanced the incorporation of [35S]taurine label in whole cell, 10% trichloroacetic acid insoluble, and 10% trichloroacetic acid soluble cell fractions.  相似文献   

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Members of Amoebophrya ceratii complex are known to infect a number of free‐living dinoflagellates including harmful algal bloom species. In August and October 2012, Amoebophrya infections during two bloom events of the dinoflagellate Cochlodinium polykrikoides were observed along southern coastal waters of Korea. Microscopic observations and molecular data revealed that two different Amoebophrya parasites infected the same host species. In addition, while one developed in the host's nucleus, the other in the host's cytoplasm. Phylogenetic analyses showed that the two parasites were not nested in the previously recognized “Amoebophrya ceratii complex clade”, which contained sequences of parasites infecting numerous dinoflagellate species. Instead, they branched as sister taxa to the isolate (possibly Amoebophrya) from radiolarians Hexacontium gigantheum. Our result indicates that the two Amoebophrya parasites infecting C. polykrikoides may be different species from those inside the “complex.”  相似文献   

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