Nutritional requirements for conidial germination and hyphal growth of Beauveria bassiana

Nutritional requirements for germination and growth of the entomopathogenic fungus Beauveria bassiana are not complex. For germination to occur, a utilizable source of carbon must be present; however, a nitrogen source is needed for continued hyphal growth, otherwise lysis ensues. Compounds that can serve as utilizable carbon-energy sources for germination include glucose, N-acetylglucosamine, glucosamine, chitin, starch, lanolin, hydrocarbons in crude oil, and some longer-chain fatty acids. Both organic and inorganic sources of nitrogen are readily utilized for growth. Conidia undergo active metabolism soon after being placed in a suitable growth medium, indicating that conidia are released from their state of dormancy several hours before emergence of the germ tube can be observed. Because of the nutritional versatility of B. bassiana, this fungus should be able to survive and be infective in several types of natural environments.     

Description of Trilineellus clathrocutis n.g., n.sp. (Tylenchorhynchinae: Tylenchida Thorne, 1949) with a Key to Species and Observations on Tylenchorhynchus sensu stricto

TrilineeIlus clathrocutis n.g., n.sp. is described and illustrated. It was found as an associate of corn (Zea mays) in Stockton, Georgia, USA, and is related to a group of Tylenchorhynchus sensu lato species having three lines in nonareolated lateral fields. This new species is closely related to Tylenehorhynehus divittatus Siddiqi 1961, T. sculptus Seinhorst 1963, and T. triglyphus Seinhorst 1963 (syn. T. chonai Sethi & Swarup 1968) Tarjan 1973. It differs from these species primarily by having longitudinal striae on the body. These four species are differentiated from Tylenchorhynchus sensu stricto by having three lateral lines instead of four. They differ from Uliginotylenchus Siddiqi 1971 by having nonareolated lateral fields, fewer than 25 annules on conoid rounded tails, differently shaped gubernacula, nonattenuated stylets, and other distinctive characters. They differ from Triversus Sher 1973 by having the male tail enclosed by the bursa and by having rounded female tails. SEM observations of T. clathrocutis reveal a cuticle deeply cut by longitudinal and horizontal striae and bearing wide (> 2.0 μm) annules. Trilineellus is proposed to accommodate the new species and the three-incisured species still within Tylenchorhynchus. Tylenchorhynchus is thereby the repository for species within Tylenchorhynchinae having four lines in the lateral field, no conspicuous labial disc, and bursa enclosing the male tail.     

Subsarcolemmal mitochondria and capillarization of soleus muscle fibers in young rats subjected to an endurance training

Summary Rats, 6 weeks old, were subjected to a program of endurance running for 3, 6 and 12 weeks. 0.5 to 0.8 m thick sections of Epon embedded soleus muscles were studied with morphometric methods.In cross-sections the area occupied by subsarcolemmal mitochondria was independent of the age, but was 53% higher after 12 weeks of training. The mean depth of the zones with subsarcolemmal mitochondria increased only 15% to about 0.9 m. Thus, the subsarcolemmal mitochondria showed a pronounced spreading at the muscle fiber surface in trained muscles. — The number of capillaries per fiber decreased slightly in controls and increased not significantly in trained muscles.It is concluded that the subsarcolemmal mitochondria supply the energy for the active transport of metabolites through the sarcolemma in oxidative muscle fibers, and that they are the limiting factor for endurance performance of the soleus muscle fibers because the changes in the capillarization were only small. It is suggested that the subsarcolemmal and the interfibrillar mitochondria have different functions and may therefore represent different types of mitochondria which can be distinguished by their morphology as well as by their biochemical properties.     

Detection of Protein A Produced by Staphylococcus aureus with a Fiber-optic-based Biosensor

Staphylococcus aureus is a pathogen important in causing human infections and intoxication. A sensitive fiber-optic that produces evanescent waves was developed for the detection of protein A, a product secreted only by S. aureus. In the immunosensor, a 40-mV argon-ion laser that generated laser light at 488 nm was used together with plastic optical fiber and antibodies to protein A were physically adsorbed onto the fiber. The principle of the detection involved a sandwich immunoassay with fluorescein isothiocyanate conjugated with anti-(protein A) immunoglobulin G to produce signals of the antigen-antibody reaction. The detection limit was 1 ng of protein A per milliliter. The fiber-optic immunosensor could be used for rapid and specific detection of S. aureus in clinical specimens and foods.     

不同生育期玉米上草地贪夜蛾的发生为害规律

2019年在广东湛江、江门调查了玉米上草地贪夜蛾Spodoptera frugiperda (Smith)发生为害动态,分析了不同生育期玉米上该虫发生为害差异规律。发现各个地区草地贪夜蛾的虫口数量与玉米受害程度存在较大差异,呈现不均衡性;该虫对玉米苗期为害最严重,其次为大喇叭口期;建立了2个地区玉米6个生育期受害率与虫口数量之间的线性回归模型。研究结果可为草地贪夜蛾监测预警及防控提供参考。     

不同品种玉米对草地贪夜蛾生长发育及繁殖的影响

为评价新入侵害虫草地贪夜蛾对我国不同品种玉米的为害潜能,本文采用组建实验种群生命表的方法研究了草地贪夜蛾对3种甜质型玉米(穗甜1号、正甜68和华金甜1号)以及3种糯质型玉米(京科糯2000、广黑甜糯和广糯1号)的生存适合度,分析了草地贪夜蛾生物学指标与玉米叶片主要营养物质及粗纤维含量间的相关性。结果表明: 取食甜质型玉米的草地贪夜蛾的幼虫存活率、蛹重、雌成虫产卵量均显著高于取食糯质型玉米;取食甜质型玉米草地贪夜蛾的内禀增长率介于0.1566～0.1843,净生殖力介于187.97～353.35,也均高于取食糯质型玉米(内禀增长率介于0.0998～0.1465,净生殖力介于25.89～95.34),表明取食甜质型玉米的草地贪夜蛾具有更高的种群增长能力。甜质型玉米叶片中主要营养物质维生素C、淀粉、可溶性糖、蛋白质、脂肪、总氨基酸及粗纤维的含量普遍高于糯质型玉米,草地贪夜蛾的净生殖力与维生素C、淀粉、可溶性糖、蛋白质及粗纤维的含量均存在显著正相关关系。草地贪夜蛾在甜质型玉米上具有更高的生存适合度。     

北京市某社区女性居民膳食模式与常见慢性病的关系

目的：了解北京市某社区女性居民的主要膳食模式及与常见慢性病的关系。方法：于2018年5月--2019年2月,采用多阶段整群随机抽样的方式对辖区内460名18~70岁女性居民进行问卷调查。收集基本资料、饮食行为习惯、家族病史、慢病史、治疗史等情况,分析饮食行为对常见慢性病的影响。结果：北京市白纸坊社区女性居民共有4种主要膳食模式,分别为：“传统膳食模式”（占43.1%）、“以肉类为主膳食模式”（占27.9%）、“水果蛋奶膳食模式”（占16.4%）和“主食、酒类和饮料膳食模式”（占12.6%）。Logistic 回归分析提示：在控制混杂因素后,“以肉类为主膳食模式”和“主食、酒类和饮料膳食模式”与社区女性居民高血压呈正相关性（OR=1.314和1.995,P<0.05）。“传统膳食模式”和“主食、酒类和饮料膳食模式”与社区女性居民糖尿病呈正相关性（OR=1.239和1.332,P<0.05）。“以肉类为主膳食模式”和“主食、酒类和饮料膳食模式”与社区女性居民血脂异常呈正相关性（OR=1.902和1.557,P<0.05）。“以肉类为主膳食模式”与社区女性居民冠心病呈正相关性（OR=1.338,P<0.05）。结论：社区女性居民膳食模式构成存在一定的不合理,且与主要慢性病的发生相关,应控制相关影响因素,促进健康、合理的膳食模式,降低慢性病的发生。     

Modulation of transmembrane pressure in manufacturing scale tangential flow filtration N-1 perfusion seed culture

Mammalian cells were grown to high density in a 3,000 L culture using perfusion with hollow fibers operated in a tangential flow filtration mode. The high-density culture was used to inoculate the production stage of a biomanufacturing process. At constant permeate flux operation, increased transmembrane pressures (TMPs) were observed on the final day of the manufacturing batches. Small scale studies suggested that the filters were not irreversibly fouled, but rather exposed to membrane concentration polarization that could be relieved by tangential sweeping of the hollow fibers. Studies were undertaken to analyze parameters that influence the hydrodynamic profile within hollow fibers; including filter area, cell density, recirculation flow rate, and permeate flow rate. Results indicated that permeate flow rate had the greatest influence on modulating TMP. Further evaluation showed a significant decrease in TMP when permeate flow was reduced, and this occurred without any negative effect on cell growth or viability. Hence, a 30% reduction of permeate flow rate was implemented at manufacturing scale. A stable operation was achieved as TMP was successfully reduced by 75% while preserving all critical factors for performance in the perfusion bioreactor.