Response of three lotic assemblages to riparian and catchment‐scale land use: implications for designing catchment monitoring programmes

1. Although many studies have focussed on the effects of catchment land use on lotic systems, the importance of broad (catchment) and fine (segment/reach) scale effects on stream assemblages remain poorly understood. 2. Nine biological metrics for macrophytes (498 sites), benthic macroinvertebrates (491) and fish (478) of lowland and mountain streams in four ecoregions of France and Germany were related to catchment and riparian buffer land use using partial Redundancy Analysis and Boosted Regression Trees (BRTs). 3. Lotic fauna was better correlated (mean max., r = 0.450) than flora (r = 0.277) to both scales of land use: the strongest correlations were noted for mountain streams. BRTs revealed strong non‐linear relationships between mountain assemblage metrics and land use. Correlations increased with increasing buffer lengths, suggesting the importance of near‐stream land use on biotic assemblages. 4. Several metrics changed markedly between 10–20% (mountain ecoregions) and 40–45% (lowland) of arable land use, irrespective of the buffer size. At mountain sites with >10% catchment arable land use, metric values differed between sites with <30% and sites with >30% forest in the near‐stream riparian area. 5. These findings support the role of riparian land use in catchment management; however, differences between mountain and lowland ecoregions support the need for ecoregion‐specific management.     

Crypsis in a heterogeneous environment: relationships between changeable polymorphic colour patterns and behaviour in a galaxiid fish

1. The ability to achieve optimal camouflage varies between microhabitats in heterogeneous environments, potentially restricting individuals to a single habitat or imposing a compromise on crypsis to match several habitats. However, animals may exhibit morphological and behavioural attributes that enhance crypsis in different habitats. 2. We used an undescribed fish species, Galaxias‘nebula’, to investigate two objectives. First, we examined two potential methods of enhancing crypsis: change in colour pattern and selection of a suitable background. Second, we characterised the colour pattern of this unstudied fish and assessed its capacity for crypsis. 3. No background selection was apparent but the area of dark pigment expressed varied between backgrounds, which may negate the requirement to be choosy about habitats. The capacity to change colour and selection of a background that maximises crypsis are most likely separate, non‐mutually exclusive strategies. 4. Galaxias‘nebula’ exhibits polymorphic, non‐interchangeable colour patterns that have elements of both background pattern matching and disruptive colouration. This, coupled with habitat characteristics, suggests a combination of generalist and specialist strategies of habitat use. The fish’s camouflage strategy and air‐breathing ability may be key to survival under increasing pressure from habitat degradation and invasive predators.     

运动结构背景对视觉系统神经元反应的调制作用

对蟾蜍的５６个视顶盖神经元的视觉反应进行了定量考察和分析,发现它们不仅对黑目标起反应,也对结构目标起反应．同相运动的结构背景使５３．５％的神经元的反应完全抑制,而异相运动则只有１０％的神经元完全被抑制,却有２１．６％的神经元反应增强．遮盖感受野（ＲＦ）中心区,则同相运动使某些细胞脱抑制,而异相运动使其抑制强度稍有增强．遮盖ＲＦ的外周区,几乎全部研究过的神经元对结构背景运动本身也起反应。本研究还发现,如果预先将一目标放在兴奋性感受野（ＥＲＦ）中央静止不动,并使结构背景在水平方向匀速移动较长时间后突然停止运动,则被研究过的６６个视盖神经元中有２９个发放一串脉冲,即神经元的运动后放电．各个神经细胞放电的脉冲多寡不一。若在ＥＲＦ中央不放置静止目标,仅是结构背景的水平运动不能诱发放电．此效应的出现,既与目标背景间反差符号（即目标为白色或黑色）无关,也与背景的运动方向无关。为诱发这一效应,不仅要求背景运动时间较长（至少在２０秒以上）,而且目标的面积要有足够大。     

《中国真菌志》50年编研成果及展望

历经几代真菌人的艰苦奋斗,《中国真菌志》目前已出版65卷,其中子囊菌类有35卷、担子菌类26卷、接合菌类1卷、卵菌1卷、黏菌2卷;上述卷册记录923属9 228种及种下分类群。编研涉及大型和小型的类群、腐生菌、食药用菌、菌根真菌、作物和林木病原菌、捕食性真菌、虫生菌、菌生真菌以及毒菌等。编研过程中发现并发表了大量新分类群,丰富了对菌物物种多样性的认知。归纳已有成果,已立项卷册应加快编研和出版进度;资源调查与分类学研究需进一步加强,按分类群(专科、专属)继续开展编研工作,注重拟参编类群的前期研究积累;以下分类群值得在后续工作中予以关注：水霉目等部分卵菌、壶菌类、座囊菌纲部分类群、盘菌纲和锤舌菌纲中尚未参编的主要类群、伞菌纲中具有小型子实体的类群等。由于分类系统在不断更新和完善,已出版卷册中使用的部分名称和分类地位的处理需依据被大多数学者所公认的分类系统给予适时的订正。期待建设一支继往开来的菌物分类学研究队伍,不断取得令世人瞩目的编研成果,为我国菌物资源利用和物种保护提供科学依据。     

MicroID2: A Novel Biotin Ligase Enables Rapid Proximity-Dependent Proteomics

Identifying protein–protein and other proximal interactions is central to dissecting signaling and regulatory processes in cells. BioID is a proximity-dependent biotinylation method that uses an “abortive” biotin ligase to detect proximal interactions in cells in a highly reproducible manner. Recent advancements in proximity-dependent biotinylation tools have improved efficiency and timing of labeling, allowing for measurement of interactions on a cellular timescale. However, issues of size, stability, and background labeling of these constructs persist. Here we modified the structure of BioID2, derived from Aquifex aeolicus BirA, to create a smaller, highly active, biotin ligase that we named MicroID2. Truncation of the C terrminus of BioID2 and addition of mutations to alleviate blockage of biotin/ATP binding at the active site of BioID2 resulted in a smaller and highly active construct with lower background labeling. Several additional point mutations improved the function of our modified MicroID2 construct compared with BioID2 and other biotin ligases, including TurboID and miniTurbo. MicroID2 is the smallest biotin ligase reported so far (180 amino acids [AAs] for MicroID2 versus 257 AAs for miniTurbo and 338 AAs for TurboID), yet it demonstrates only slightly less labeling activity than TurboID and outperforms miniTurbo. MicroID2 also had lower background labeling than TurboID. For experiments where precise temporal control of labeling is essential, we in addition developed a MicroID2 mutant, termed lbMicroID2 (low background MicroID2), that has lower labeling efficiency but significantly reduced biotin scavenging compared with BioID2. Finally, we demonstrate utility of MicroID2 in mass spectrometry experiments by localizing MicroID2 constructs to subcellular organelles and measuring proximal interactions.     

A new method for identifying rapid decline dynamics in wild vertebrate populations

Tracking trends in the abundance of wildlife populations is a sensitive method for assessing biodiversity change due to the short time‐lag between human pressures and corresponding shifts in population trends. This study tests for proposed associations between different types of human pressures and wildlife population abundance decline‐curves and introduces a method to distinguish decline trajectories from natural fluctuations in population time‐series. First, we simulated typical mammalian population time‐series under different human pressure types and intensities and identified significant distinctions in population dynamics. Based on the concavity of the smoothed population trend and the algebraic function which was the closest fit to the data, we determined those differences in decline dynamics that were consistently attributable to each pressure type. We examined the robustness of the attribution of pressure type to population decline dynamics under more realistic conditions by simulating populations under different levels of environmental stochasticity and time‐series data quality. Finally, we applied our newly developed method to 124 wildlife population time‐series and investigated how those threat types diagnosed by our method compare to the specific threatening processes reported for those populations. We show how wildlife population decline curves can be used to discern between broad categories of pressure or threat types, but do not work for detailed threat attributions. More usefully, we find that differences in population decline curves can reliably identify populations where pressure is increasing over time, even when data quality is poor, and propose this method as a cost‐effective technique for prioritizing conservation actions between populations.     

罗汉果组培繁殖的技术要点

报道罗汉果组培繁殖的各项主要技术要点,包括组培条件、培养基的配制、外植体的选取与消毒、接种与培养、种源保存、炼苗与移栽、苗木包装与运输等。提出了5种培养基参考配方,即茎段诱导培养:MS+BA0.5～1.0mg/L+IAA(NAA)0.05～0.1mg/L+白糖3%+琼脂4.5g/L,pH5.8;茎尖诱导培养:MS+BA0.5～1.0mg/L+NAA0.05～0.1mg/L+椰子水100mL+白糖3%+琼脂4.5mg/L,pH5.8;继代培养(丛生芽方式):MS+BA0.3～0.7mg/L+NAA0.05/IAA0.1mg/L+白糖3%+琼脂4.5mg/L,pH5.8;继代培养(微型扦插方式):MS+BA0.1mg/L+IAA0.3mg/L+活性炭0.07g/L+白糖3%+琼脂4.5mg/L,pH5.8;生根培养:MS+BA0.07mg/L+IBA0.15mg/L+IAA0.1mg/L+活性炭0.1g/L+白糖3%+琼脂4.5mg/L,pH5.8。分析了外植体培养过程中可能出现的不良状况的原因并提出预防措施,明确了炼苗移栽的适宜条件并制定出相应的管理方法。形成了一套较为完整的罗汉果组培苗繁殖生产技术规程。