The effects of starving and feeding on Dover sole (Solea solea,Soleidae, Linnaeus, 1758) stress response and early larval development

In the view of an urgent necessity to improve the quantity and the quality of farmed fish species, there is a strong need to improve our basic knowledge on the effects of first feeding during the developmental stages of fish larvae. High mortality, mainly due to food deprivation or inappropriate food quality, has been observed in many larval fish species, but knowledge about the morphological, biochemical and molecular processes related to this topic is still poorly understood. The understanding of the early larval ontogeny as well as the larval nutritional requirements and the molecular and cellular mechanisms elicited by fish larvae during food deprivation and starvation are thus of primary importance. At this regard, this study investigates, in Dover sole larvae, the effects of starvation and starving/re‐feeding procedures at a morphological, histological, biochemical and molecular level. The results evidenced that starved larvae progressively decrease in growth, lipid content, affected their gastrointestinal tract and muscle development and increased cortisol and heat shock protein 70 levels. On the contrary, starved and re‐fed larvae showed, after the restoration of a favourable feeding condition, a compensatory growth. In conclusion, this is the first study analysing through a multidisciplinary approach the effects of food deprivation on the development of an important economic species, the Dover sole.     

松材线虫疫木树蔸铣削过程仿真及优化

针对松材线虫疫木所处环境复杂、难以携带普通林业设备到达疫木位置的问题,需对实地铣削松材线虫疫木树蔸粉碎机的切削刀具进行减阻特性研究,最终达到设备轻量化的目的.阐述了树蔸粉碎机的结构、工作原理及操作方法;以切削刀具单刀片为研究对象,基于Ansys的Ls-Dyna有限元显式求解程序进行松材线虫疫木树蔸铣削过程的仿真计算,构...     

System for quasi‐continuous simultaneous measurement of oxygen diffusion rate and redox potential in soil

Oxygen diffusion rate (ODR) and redox potential (E_H) are quantitative indices representing oxygen availability and redox status in soils, which is valuable information for better understanding causes and effects of soil aeration. Because these indices are spatially and temporally highly variable, continuous measurements and adequate numbers of repetitions are essential for accurate in situ monitoring. Here, we present a new, fully automated recording system for in situ measurements where ODR and E_H are measured at the same platinum electrode. The conflict between electrode polarization for ODR and the resulting biased E_H readings is solved by reducing the polarization time and introducing a recovery interval between two consecutive measurement cycles. The shorter polarization time ensures accurate E_H readings. It also results in moderately overestimated ODR readings, but this can be corrected before data analysis. The recovery interval restricts temporal resolution of the E_H‐ODR data pairs to 8 h. We illustrate the use of the system with measurements in a field experiment in Zürich, Switzerland. ODR curves at different depths ran roughly parallel to the corresponding curves of O₂ concentration in soil air but ODR was much more sensitive to precipitation. Low ODR was a necessary but not a sufficient condition for declining E_H. E_H ran parallel to O₂ concentration in soil air rather than to ODR. The fully automated system allows for time series of replicate measurements in multifactorial field studies with reasonable labor requirements. It may be particularly suitable for studies examining the effects of soil tillage, compaction, and irrigation, where structure‐related soil properties such as porosity, gas permeability, and soil aeration play a dominant role.     

茶用菊苗期枯萎病抗性鉴定技术研究

为了建立茶用菊枯萎病抗性鉴定的方法,了解茶用菊种质资源对枯萎病抗性的差异,筛选抗性种质用于抗病育种,本研究以茶用菊为试验材料,通过枯萎病病原菌分离、形态学和真菌18S rDNA/ITS鉴定和致病力研究,开展茶用菊资源苗期枯萎病人工接种鉴定,并筛选优异抗病种质。结果表明,从发病的福白菊植株上分离到M15和M16 2株枯萎病病原菌菌株,经鉴定,这2株菌株均属于尖孢镰刀菌,致病力检测发现M15为强致病力菌株。通过枯萎病抗性鉴定,筛选到七月白1份高抗品种,杭白菊、苏菊7号等9份抗病品种,滁菊、亳菊等17份中抗品种,福白菊、苏菊6号等3份感病品种以及皇菊1份高感品种。本研究建立了一种高效的茶用菊品种抗枯萎病的鉴定方法,为茶用菊抗枯萎病品种改良奠定了基础。     

“虚拟”森林碳汇的法律分析

森林碳汇原属于森林的自然属性,但因保护环境之所需,可以通过设定权利义务关系而实现其经济价值,从而使森林碳汇具有社会属性。随着技术的发展,通过手机移动APP如支付宝、移动银行、预约挂号平台等,这类森林碳汇在一定程度上均减少了现实中温室气体的排放。考虑到其与传统森林碳汇的不同,可称之为“虚拟”森林碳汇。应在法律上确认“虚拟”森林碳汇的物权属性,鼓励其进入碳排放交易市场,促使每个公民加入温室气体减排行动。这不仅能保护公民的合法财产权,而且能增强公民的环保意识,以促进环境的改善和保障经济社会的可持续、绿色发展。     

Enhancement of Arachidonic Acid Through Protoplast Regeneration Production by Mortierella isabellina Mutagenesis

A developed method was used for the enhancement of arachidonic acid production by M. isabellina. An orthogonal, rotatable and central composite design was applied to determine the optimum conditions for protoplast regeneration mutagenesis. The results showed that a commixture enzyme (cellulase and glusulase) at the concentration of 4%, enzymolysis temperature at 30°C and enzymolysis time on 7.5 h were the optimal conditions, in which the lethality of M. isabellina spores was 78.4%. After mutagenesis and re-screenings, M. isabellina mutant Y-69 was obtained. GC analysis showed that the yield of arachidonic acid by Y-69 (2.92 g·L^?1) was 3.56 times higher than that of the wild-type strain (0.82 g · L^?1). Pass generation tests showed that the properties of Y-69 by mutation were readily inherited.     

浅析真空转鼓过滤机的过滤效果

介绍大庆石化公司硫氰酸钠回收装置真空转鼓过滤机的结构及工作原理,重点讨论影响过滤效果的主要因素,针对进料、预涂效果和真空度等方面的影响,提出所采取的措施,来保证真空转鼓过滤机的过滤效果。     

Malignant transformation of a unicameral bone cyst in a cat

A unicameral bone cyst in the proximal humerus of a 3-year-old Norwegian forest cat was diagnosed by dynamic contrast-enhanced magnetic resonance imaging, surgical exploration, and histopathology. Surgical curettage and incorporation of bone cement led to full recovery. An osteosarcoma developed at the surgical site 17 months later. Thoracic radiographs showed pulmonary lesions consistent with metastasis.     

Relationships of the Sardinian isolate of tomato yellow leaf curl geminivirus with its whitefly vectorBemisia tabaci Gen

Relationships of an Italian isolate of tomato yellow leaf curl geminivirus from Sardinia (TYLCV-S) with its whitefly vectorBemisia tabaci were studied by means of experimental transmissions from tomato to tomato plants. TYLCV-S was confirmed to be transmitted in a persistent, circulative manner. The minimum latent period in the vector was between 17 and 20 h from the beginning of the acquisition access period (AAP). The maximum retention of infectivity was 8 days from the end of the AAP. Both acquisition and inoculation feeding times influenced the detected proportion of infective insects, with patterns well described by an exponential model. Acquisition was more efficient than inoculation. Males were significantly less efficient vectors than females. Nymphs were as efficient as adults in acquiring the virus. The length of AAP influenced both the retention of infectivity, and the pattern of transmission in serial transfer transmission tests with individual females. No significant difference in transmission efficiency was detected between two colonies ofB. tabaci, one inducing typical silverleaf symptoms on squash, the other inducing only mild symptoms with more than 50 whiteflies per plant. The phenomenon of periodic acquisition was not unequivocally proved for TYLCV-S.Research supported by the National Research Council of Italy, Special Project RAISA, Sub-project N. 2. Paper N. 1961.Supported by a grant from the Istituto Agronomico Mediterraneo, Valenzano (Bari), Italy.     

香蕉茎尖滴冻法保存中细胞的超微结构变化

 应用透射电镜研究了香蕉茎尖滴冻法超低温保存中细胞超微结构的变化规律。结果表明: 装载后, 细胞液泡化程度降低, 出现质壁分离。脱水处理使质壁分离程度加重, 原生质体浓缩, 一部分细胞的细胞壁、膜系统发生了不可逆的损伤; 也有小部分位于分生组织区域的细胞结构虽然发生了变化, 但程度不深, 在恢复培养时会自动修复, 并再生出植株。细胞严重伤害主要发生在脱水处理过程中, 冷冻环节基本上不产生新的损伤。讨论了上述变化的可能机制。