植物合成生物学领域发展态势的文献计量分析

合成生物学作为一种颠覆性技术可应用于农业领域的创新发展,解决当前农业学科中的瓶颈问题。利用文献计量学方法从领域发表论文的时序数量分布、主题分布等探测当前合成生物学的基本态势。基于领域的主题分布可知,其中植物合成生物学这一主题是稳定存在的且主题规模处于稳定增长趋势。聚焦植物合成生物学这一主题方向,在构建引文网络的基础上利用主路径分析方法从知识流动角度探测植物合成生物学领域重要知识节点,内容涵盖介子油苷生物合成途径,重要催化酶功能解析、转录因子的调控作用,组学方法的应用,利用微生物酵母进行生物物质合成,这些内容表征了合成生物的核心理论技术。     

靶向蛋白质降解技术研究进展

靶向蛋白质降解技术可有效克服DNA敲除、RNA干扰等传统药物靶点确认及干扰策略的局限性。近年来,一系列新型靶向蛋白质降解技术不断涌现,在药物研发领域展现出极好的应用前景。本文综述了靶向蛋白质降解技术的最新研究进展,重点介绍各种技术的作用机制、应用情况、技术优势及目前存在问题,以期为药物靶点确认及新药开发提供有力理论及技术支持。     

拟南芥微丝加帽蛋白β亚基参与壳梭孢素诱导的气孔开放过程

气孔是植物响应外源信号,与环境进行水分和气体交换的门户。由外源信号引起的保卫细胞微丝骨架动态变化在气孔运动中发挥重要作用,但是具体的精确调节机制仍不清楚。微丝结合蛋白家族(ABPs) 是微丝动态组装最直接的调控者,它们的作用不容忽视。本文运用反向遗传学,以微丝结合蛋白—加帽蛋白 (CP) β-亚基 (CPB) 突变体cpb-3为实验材料,探究其在壳梭孢素 (FC)诱导气孔开放中的作用。结果发现:离体叶片干燥3 h,cpb-3突变体的叶片失水率为63.45%,明显高于野生型的48.99%。气孔开度测量及激光共聚焦显微镜观察发现,cpb-3突变体的气孔开放程度以及微丝动态重排对FC分子更敏感。气孔开度相比野生型增大了20% (P<0.05),含辐射状微丝排布的保卫细胞数量比例增幅达到58.3%,比对照组高出18.5%。此外,非损伤微测技术记录保卫细胞Ca²⁺、K⁺等跨膜运输动态,FC处理下,cpb-3突变体保卫细胞中Ca²⁺外流速度升至212.86 pmol cm^-2s^-1,野生型仅为68.76 pmol cm^-2s^-1,明显快于野生型。且K⁺内流也有相同表现。综上表明,微丝加帽蛋白CP的β亚基CPB可能通过调节保卫细胞微丝骨架动态重排以及离子流动,在FC诱导的气孔运动中发挥重要的作用。     

Developmental staging table of the green iguana

Embryonic staging tables provide information to standardize embryological investigations and to subsidize discussions about evolution. We have established a developmental staging table for Iguana iguana iguana. The sample was composed of 142 embryos, incubated at a constant temperature and collected at regular intervals. Morphological features as pharyngeal arches, craniofacial structures, eyes, limbs, claws, pigmentation, scales and egg tooth were evaluated to determine development stages. The normal staging table includes 17 stages from oviposition to hatching, based on chronology and morphological external features. Stages from 1 to 27 occur before oviposition. Stage 28 was the first described, because all embryos presented limb bud anlage, key feature of the previous stage. We used pharyngeal arches and limb buds to describe the first stages; claws, genital papilla and scales to describe the middle stages; and pigmentation, size and egg tooth to describe the last stages. Incubation lasted approximately 2 months in a controlled environment. The results were similar to the data from other lizards, confirming the embryonic conservative pattern of the group.     

Using unmanned aerial vehicle‐based multispectral,RGB and thermal imagery for phenotyping of forest genetic trials: A case study in Pinus halepensis

The assessment of genetic differentiation in functional traits is fundamental towards understanding the adaptive characteristics of forest species. While traditional phenotyping techniques are costly and time‐consuming, remote sensing data derived from cameras mounted on unmanned aerial vehicles (UAVs) provide potentially valid high‐throughput information for assessing morphophysiological differences among tree populations. In this work, we test for genetic variation in vegetation indices (VIs) and canopy temperature among populations of Pinus halepensis as proxies for canopy architecture, leaf area, photosynthetic pigments, photosynthetic efficiency and water use. The interpopulation associations between vegetation properties and above‐ground growth (stem volume) were also assessed. Three flights (July 2016, November 2016 and May 2017) were performed in a genetic trial consisting of 56 populations covering a large part of the species range. Multispectral (visible and near infrared wavelengths), RGB (red, green, blue) and thermal images were used to estimate canopy temperature and vegetation cover (VC) and derive several VIs. Differences among populations emerged consistently across flights for VC and VIs related to leaf area, indicating genetic divergence in crown architecture. Population differences in indices related to photosynthetic pigments emerged only in May 2017 and were probably related to a contrasting phenology of needle development. Conversely, the low population differentiation for the same indices in July 2016 and November 2016 suggested weak interpopulation variation in the photosynthetic machinery of mature needles of P. halepensis. Population differences in canopy temperature found in July 2016 were indicative of variation in stomatal regulation under drought stress. Stem volume correlated with indices related to leaf area (positively) and with canopy temperature (negatively), indicating a strong influence of canopy properties and stomatal conductance on above‐ground growth at the population level. Specifically, a combination of VIs and canopy temperature accounted for about 60% of population variability in stem volume of adult trees. This is the first study to propose UAV remote sensing as an effective tool for screening genetic variation in morphophysiological traits of adult forest trees.     

Ontogenetic change in the amount and position of slow-oxidative myotomal muscle in relationship to regional endothermy in juvenile yellowfin tuna Thunnus albacares

Myotomal slow-oxidative muscle (SM) powers continuous swimming and generates heat needed to maintain elevated locomotor muscle temperatures (regional endothermy) in tunas. This study describes how the amount and distribution of myotomal SM increases with fish size and age in juvenile yellowfin tuna Thunnus albacares in relationship to the development of regional endothermy. In T. albacares juveniles 40–74 mm fork length (L_F; n = 23) raised from fertilised eggs at the Inter-American Tropical Tuna Commission Achotines Laboratory in Panama and larger juveniles (118–344 mm L_F; n = 5) collected by hook and line off of Oahu, Hawaii, USA, SM was identified by histochemical staining for the mitochondrial enzyme succinic dehydrogenase or by colour (in the two largest individuals). The cross-sectional area of myotomal SM at 60% L_F, a position with maximal percentage of SM in larger T. albacares, increased exponentially with L_F. The percentage of total cross-sectional area composed of SM at 60% L_F increased significantly with both L_F and age, suggesting that SM growth occurs throughout the size range of T. albacares juveniles studied. In addition, the percentage of SM at 60% L_F that is medial increased asymptotically with L_F. The increases in amount of SM and medial SM, along with the development of the counter-current heat-exchanger blood vessels that retain heat, allow larger tuna juveniles to maintain elevated and relatively stable SM temperatures, facilitating range expansion into cooler waters.     

Atlantic salmon Salmo salar passing a natural barrier before and after construction of a hydroelectric station

A hydro power plant constructed around a waterfall on a coastal spate river, used the fall as a natural fish pass and applied a previous telemetry study on local Atlantic salmon Salmo salar to determine the abstraction conditions for the site. The current study used the same telemetry approach to monitor the efficacy of S. salar passage and to compare migratory behaviour at the waterfall pre and post the hydro development. The probability of S. salar successfully crossing the waterfall was higher post-hydro when 80% of tagged fish successfully crossed in comparison to the pristine pre-hydro period when 44% of tagged fish ascended. The flow range used by tagged S. salar to cross the waterfall ranged from 2.49−7.87 m³ s⁻¹ in the pre-hydro period but broadened to 1.32−12.91 m³ s⁻¹ during the post-hydro period. This was principally due to the hydro diverting water away from the waterfall during spate conditions, damping the flow across the barrier and facilitating upstream migration within a more suitable discharge range. During 2017–2018 implementation of the hydro-operation protocol elongated the duration of the migratory window for successful upstream migration by 36–128%. A strong diurnal pattern was observed for movements across the Salmon Leap waterfall during both the pre-hydro and post-hydro monitoring periods with most tagged S. salar crossing the complex obstacle in daylight.