Interactions between imprinting effects in the mouse

Mice with uniparental partial or complete disomies for any one of 11 identified chromosomes show abnormal phenotypes. The abnormalities, or imprinting effects, can be attributable to an incorrect dosage of maternal or paternal copies of imprinted gene(s) located within the regions involved. Here we show that combinations of partial disomies may result in interactions between imprinting effects that seemingly independently affect fetal and/or placental growth in different ways or modify neonatal and postnatal imprinting effects. Candidate genes within the regions have been identified. The findings are generally in accord with the "conflict hypothesis" for the evolution of genomic imprinting but do not clearly demonstrate common growth axes within which imprinted genes may interact. Instead, it would seem that any gene that represses or limits embryonic/fetal growth to the advantage of the mother--by any developmental means--will have been subject to evolutionary selection for paternal allele repression. Likewise, any gene that favors embryonic/fetal development at consequent cost to the mother--by any developmental means--will have faced selection for maternal allele repression. The classical Igf2-Igf2r axis may therefore be unique. The findings involve reinterpretation of older imprinting data and consequently revision of the mouse imprinting map.     

海草与其附生藻类之间的相互作用

海草床是滨海湿地中重要的生态系统,近年来世界范围内出现大面积的海草床衰退,水体富营养化引发附生藻类的大量繁殖是其中的一个主要原因。本文综述了近20年来关于海草与其附生藻类之间相互作用的研究进展,包括海草床中附生藻类的地位及其积极作用,附生藻类与海草的物质交换关系,附生藻类对海草的影响（主要是光利用限制和营养物质利用限制）。对海草床中海草-附生藻类群落复杂的生态关系提出了研究展望,包括海草与其附生藻类的物质交换机制,海草与其附生藻类对营养物质利用的竞争关系,附生藻类生物量分别对海草可利用光和光合作用能力的削弱关系,海草与附生藻类对海草床初级生产力的贡献随环境因子的变化关系,通过原位观测数据的积累建立海草生长与生物作用的模型等。     

Interactions between wood-inhabiting fungi and termites: a meta-analytical review

The foraging behavior and survivorship of termites are modified by the presence of wood-inhabiting fungi. Nonetheless, it is not clear if these interactions are beneficial, negative, or neutral for termites. We conducted a meta-analytical review to determine if the presence of wood-inhabiting fungi affects the foraging behavior and survivorship of termites. Overall, the presence of wood-inhabiting fungi in a resource used by termites was positive, increasing resource consumption by 120%, and aggregation behavior by 81%. The presence of fungi also increased termite trail-following by approximately 200% and increased survival by 136%. The results varied, however, according to the type of fungi evaluated. Decay fungi and sap-stain fungi elicited positive responses in termites, whereas molds did not affect the consumption of cellulose by termites. Amongst the decay fungi group, white-rot fungi caused the strongest and most positive response in all termite behaviors evaluated, although brown-rot fungi is known to be preferred by termites. The results of our study, therefore, suggest that wood-inhabiting fungi are potential facilitators of the foraging behavior and survivorship of termites. These results have great implications for termite biocontrol, as well as for knowledge of the ecological aspects of termite–fungi interactions.     

Interactions between climate and habitat loss effects on biodiversity: a systematic review and meta‐analysis

Climate change and habitat loss are both key threatening processes driving the global loss in biodiversity. Yet little is known about their synergistic effects on biological populations due to the complexity underlying both processes. If the combined effects of habitat loss and climate change are greater than the effects of each threat individually, current conservation management strategies may be inefficient and at worst ineffective. Therefore, there is a pressing need to identify whether interacting effects between climate change and habitat loss exist and, if so, quantify the magnitude of their impact. In this article, we present a meta‐analysis of studies that quantify the effect of habitat loss on biological populations and examine whether the magnitude of these effects depends on current climatic conditions and historical rates of climate change. We examined 1319 papers on habitat loss and fragmentation, identified from the past 20 years, representing a range of taxa, landscapes, land‐uses, geographic locations and climatic conditions. We find that current climate and climate change are important factors determining the negative effects of habitat loss on species density and/or diversity. The most important determinant of habitat loss and fragmentation effects, averaged across species and geographic regions, was current maximum temperature, with mean precipitation change over the last 100 years of secondary importance. Habitat loss and fragmentation effects were greatest in areas with high maximum temperatures. Conversely, they were lowest in areas where average rainfall has increased over time. To our knowledge, this is the first study to conduct a global terrestrial analysis of existing data to quantify and test for interacting effects between current climate, climatic change and habitat loss on biological populations. Understanding the synergistic effects between climate change and other threatening processes has critical implications for our ability to support and incorporate climate change adaptation measures into policy development and management response.     

Interactions between plants and herbivores: A review of plant defense

Ecologists have long ignored or underestimated the importance of plant–herbivore interactions owing to the diversities of herbivores, plant defensive strategies and ecological systems. In this review, we briefly discussed the categories of herbivores. Then we reviewed the major types of plant defenses against herbivores. Selective forces of herbivore pressures have led to the evolution of various defensive mechanisms in plants, which can be classified into (i) resistance traits that reduce the amount of damage received, including physical, chemical, and biotic traits; (ii) tolerance mechanisms that decrease the impact of herbivore damage, and (iii) escape strategies that reduce the probability of plants to be found by herbivores. These strategies have been studied at different levels from molecular genetics and genomics, to chemistry and physiology, to community and ecosystem ecology. We summarized the development of the methodology for studying plant defenses against herbivores. Particularly, 24 of those hypotheses and models, which are influential in the international community concerning the relationship between plants and herbivores, including the defensive mimicry hypothesis, the compensatory continuum hypothesis, the slow-growth-high-mortality hypothesis, etc, were introduced and grouped into four categories according to plant defense strategies in the present review. Finally, we also reviewed the research progress of plant–herbivore interactions in China, and discussed the perspectives of studies on plant–herbivore interactions.     

Interactions between invasive plants and heavy metal stresses: a review

入侵植物与重金属胁迫的相互作用研究进展 全球变化改变了植物群落的分布格局,包括入侵植物,而人为污染可能降低本地植物对入侵植物的抗性。因此,本文总结了近几十年本地植物、入侵植物和植物-土壤生态系统中重金属生物地球化学行为的研究,以加深我们对入侵植物与环境胁迫因子相互作用的认识。我们的研究结合已有文献报道表明：(i)入侵物种对环境胁迫的影响具有异质性, (ii)影响的大小是多变的, (iii)即使在同一影响类型内,影响类型也具有多向性。然而,入侵植物暴露在重金属环境中表现出更强的自我保护机制,对重金属的生物可利用性和毒性有正向或负向的影响。另一方面,由于入侵植物普遍具有较高的耐受性,加之本地植物暴露于有毒重金属污染时具有“逃逸行为”,重金属胁迫环境更有利于植物的成功入侵。但是,对于入侵植物的重金属等元素组成是否与污染地区的本地植物不同,目前尚无共识。因此,在全球范围内对外来入侵植物与本土植物的植物体内、凋落物和土壤污染物含量进行定量比较是今后研究的一个重要方向。     

入侵植物与丛枝菌根真菌的相互作用

入侵植物的入侵改变了入侵地生物群落的结构,导致生物多样性的丧失.丛枝菌根真菌(AMF)作为陆地生态系统中土壤微生物普遍的组成部分,它的种类和组成能够影响入侵植物的生长表现.这种真菌与寄主(入侵植物)特殊的关系也暗示了AMF能够影响入侵植物的入侵.反之,入侵植物的入侵同样也会影响AMF的群落结构和功能.本文在简要总结我国入侵植物种类及其危害的基础上,着重探讨了AMF与入侵植物入侵之间的关系,即AMF对入侵植物入侵过程中的作用、入侵植物入侵后如何影响AMF以及两者之间的相互作用机制.     

菌根真菌多样性与植物多样性的相互作用研究进展

菌根共生双方多样性影响着生态系统的过程与功能。菌根真菌-寄主植物之间的共生组合存在偏好性或特异性,这导致菌根真菌对寄主植物的效益差异和寄主植物对菌根真菌的利益差别：两者在互利共生过程中不仅相互选择,还存在相互促进与制约的关系(如互补与选择效应、竞争),从而在一定程度上决定生态系统的演化与发展。本文概述了植物多样性与菌根真菌多样性的相互影响,探讨了两者互作可能存在的调控因素与机制,对存在的问题和争议进行了总结,并提出了进一步研究的方向。深入阐明植物多样性与菌根真菌多样性之间的互作关系,将丰富生物共生学理论,增强菌根应用潜力及生物多样性的维持。     

组织工程中细胞与生物材料相互作用研究进展

种子细胞、生物材料和生长因子是组织工程三要素.生物材料模拟体内细胞外基质,为细胞提供良好的生长附着环境,维持细胞的活力和功能.材料表面的理化性质和表面改性分子直接影响细胞的粘附、增殖、迁移和分化等细胞行为,进而影响细胞功能和组织再生效果.材料表面修饰分子是细胞表面粘附和生长的直接接触位置,因此细胞与生物材料表面修饰分子...     

X-linked imprinting: effects on brain and behaviour

Imprinted genes are monoallelically expressed in a parent-of-origin-dependent manner and can affect brain and behavioural phenotypes. The X chromosome is enriched for genes affecting neurodevelopment and is donated asymmetrically to male and female progeny. Hence, X-linked imprinted genes could potentially influence sexually dimorphic neurobiology. Consequently, investigations into such loci may provide new insights into the biological basis of behavioural differences between the sexes and into why men and women show different vulnerabilities to certain mental disorders. In this review, we summarise recent advances in our knowledge of X-linked imprinted genes and the brain substrates that they may act upon. In addition, we suggest strategies for identifying novel X-linked imprinted genes and their downstream effects and discuss evolutionary theories regarding the origin and maintenance of X-linked imprinting.     

Interactions between microbial biofilms and marine fouling algae: a mini review

Natural and artificial substrata immersed in the marine environment are typically colonized by microorganisms, which may moderate the settlement/recruitment of algal spores and invertebrate larvae of macrofouling organisms. This mini-review summarizes the major interactions occurring between microbial biofilms and marine fouling algae, including their effects on the settlement, growth and morphology of the adult plants. The roles of chemical compounds that are produced by both bacteria and algae and which drive the interactions are reviewed. The possibility of using such bioactive compounds to control macrofouling will be discussed.     

Interactions between adult and larval bluegill sunfish: positive and negative effects

Adult fish may affect the growth and survival of conspecific larvae through a variety of pathways, including negative interactions via competition for shared limiting resources or via predation (i.e., cannibalism), and positive interactions due to the consumption of larval predators and via resource enhancement (i.e., presence of adults increases availability of larval prey). To examine the overall effect of adult bluegill sunfish (Lepomis macrochirus) on larval bluegill, we conducted a field experiment in which we manipulated adult densities and quantified larval growth and survival, prey abundance, invertebrate predator abundance, and cannibalism. The presence of adult bluegill had a negative effect on final larval mass. This response was consistent with competition for zooplankton prey. Adult bluegill reduced the abundance of large zooplankton (e.g., Chaoborus and Daphnia), which were the dominant prey of bluegill larvae in the absence of adults. Larvae in the no-adult treatment also had significantly more prey in their stomachs compared to larvae in the presence of adults. Larval survival was maximized at intermediate adult densities and the overall production of larvae peaked at intermediate adult densities. The higher larval survival at intermediate adult densities is attributed to a reduction in invertebrate predators in treatments with adult bluegill; invertebrate predators experienced an 80% reduction in the presence of adult fish. Decreased larval survival at the highest adult density was not due to resource limitation and may be due to cannibalism, which was not directly observed in our study, but has been observed in other studies.     

Interactions between Helicobacter pylori infection and host metabolic homeostasis: A comprehensive review

The microbiota actively and extensively participates in the regulation of human metabolism, playing a crucial role in the development of metabolic diseases. Helicobacter pylori (H. pylori), when colonizing gastric epithelial cells, not only induces local tissue inflammation or malignant transformation but also leads to systemic and partial changes in host metabolism. These shifts can be mediated through direct contact, toxic components, or indirect immune responses. Consequently, they influence various molecular metabolic events that impact nutritional status and iron absorption in the host. Unraveling the intricate and diverse molecular interaction links between H. pylori and human metabolism modulation is essential for understanding pathogenesis mechanisms and developing targeted treatments for related diseases. However, significant challenges persist in comprehensively understanding the complex association networks among H. pylori itself, the infected host's status, the host microbiome, and the immune response. Previous metabolomics research has indicated that H. pylori infection and eradication may selectively shape the metabolite and microbial profiles of gastric lesions. Yet, it remains largely unknown how these diverse metabolic pathways, including isovaleric acid, cholesterol, fatty acids, and phospholipids, specifically modulate gastric carcinogenesis or affect the host's serum metabolism, consequently leading to the development of metabolic-associated diseases. The direct contribution of H. pylori to metabolisms still lacks conclusive evidence. In this review, we summarize recent advances in clinical evidence highlighting associations between chronic H. pylori infection and metabolic diseases, as well as its potential molecular regulatory patterns.     

Interactions between Pisolithus tinctorius and its hosts: a review of current knowledge

 Pisolithus tinctorius (Pers.) Coker and Couch [Syn. = P. arhizus (Scop.: Pers.) Rauschert] (Pt) is a widespread ectomycorrhizal basidiomycete forming mycorrhizas with a variety of hosts. Developmental and functional aspects of the symbiosis are well documented and thus Pt has been adopted as a model organism for investigations of the molecular basis of ectomycorrhizal interactions. In this review of the current state of knowledge of interactions between Pt and its hosts we demonstrate that Pt displays much intraspecific heterogeneity of host specificity, physiology and the benefits the fungus can impart upon the host plant. It is not clear at present how far such heterogeneity reflects systematic segregation within Pt. Accepted: 20 May 1997     

细颗粒物(PM2.5)与植被关系的研究综述

细颗粒物即PM,2.5,粒径小,沉降困难,危害严重,植被在一定程度上有助于减轻颗粒物污染.本文从阐述PM2.5的沉降机理出发,分析PM2.5与植被之间的相互作用.植被的阻滞吸收作用对大气颗粒物移除存在积极影响,而过多的空气颗粒物滞留对植物生长起到一定的负面作用,但以植被对大气颗粒物的移除为主导作用.以此为基础,从林分尺度-环境特性、单木尺度-树种特性和叶片尺度-颗粒物种类和分布特性这3个角度出发,结合外界影响因素(气象学要素、空气动力学要素、大气颗粒浓度水平、植物物候变化)、气室实验以及滞留颗粒物特征等阐述植被林冠、枝干及叶片等对移除PM2.5的影响.最后,文章指出今后的研究应当向定量化方向发展,注重不同树种移除PM2.5能力的对比分析及系统研究,并针对研究区域确定防治大气PM2.5污染的优势树种.     

Interactions between verapamil and neutral and acidic liposomes: effects of the ionic strength

Patients with cancer often develop major electrolyte disorders, which are aggravated by radiation therapy and chemotherapy and by the concomitant impairment of the renal function and the development of drug resistance. In addition, tumour cells have membranes with more negative charges than normal eukaryotic cells. This study was designed to test the hypothesis that the ability of the Ca(2+) blocker verapamil to mediate the reversal of multidrug resistance (MDR) by interacting with the membrane phospholipids may be correlated with the ionic strength and membrane surface potential in resistant tumours. The permeation properties of verapamil, which is the best-known MDR-modulator, were therefore studied by quantifying its ability to induce the leakage of carboxyfluorescein through unilamellar liposomes containing various mole fractions of phosphatidic acid (x(EPA)=0, 0.1 and 0.3), at four different ionic strengths (I=0.052, 0.124, 0.204 and 0.318 M). The dye leakage induced by verapamil varied greatly with I, depending on x(EPA). The permeation process was a co-operative one (1.3相似文献