More than meets the eye: subretinal aspirate from an acutely blind dog

A 14-year-old, spayed female Cocker Spaniel was presented to the Boren Veterinary Medical Teaching Hospital at Oklahoma State University with acute loss of vision in the right eye and a history of intermittent bloody diarrhea of unknown duration. Small, white, plaque-like lesions in the retina and subretina were visualized by direct ophthalmic examination, and aspirated with ultrasound-guidance. A direct smear of the subretinal fluid was highly cellular and contained large numbers of pleomorphic organisms consistent with Prototheca sp. The structures were round, oval, or elongated, 4-6 microm width and 8-16 microm in length and surrounded by a thin, clear cell wall. Small, central, pink to purple nuclei were observed in some organisms, but in most, the nuclei were obscured by a deeply basophilic, granular cytoplasm. Some organisms contained endospores. Negatively-stained structures of similar size and shape were considered to be empty casings (theca) of ruptured sporulating and nonsporulating forms of the organism. Protothecosis usually is a disseminated, fatal disease in dogs. The Prototheca organisms observed in this case showed characteristic morphology, illustrating the ability to diagnose protothecosis in cytologic samples.     

Effects of a dietary supplement of DHA-rich marine algae on Italian heavy pig production parameters

To evaluate the effects of dietary supplementation with a marine algae product (MA) containing a high level of docosahexaenoic acid (DHA) on heavy pig production performances (including meat and subcutaneous fat quality), a trial was conducted on sixty Landrace × Large White barrows with a starting average body weight (BW) of 118 kg. Pigs were allocated to four experimental groups: a control group (A) fed a maize/soybean diet and three treatment groups in which MA was added at 2.5 g kg^− 1 over the last 8 weeks prior to slaughtering (group B) or at 5 and 2.5 g kg^− 1 over the last 4 weeks prior to slaughtering (groups C and D, respectively). Vitamin E was added at 12.5 mg kg^− 1 in the diets for groups B and D and at 25 mg kg^− 1 in the diet of group C. The four diets were formulated so as to supply the same amount of nutrients, with exception of vitamin E. Pigs were fed at a rate of 9% of their metabolic BW (BW^0.75) up to a maximum of 2.9 kg of dry matter per pig per day. Pigs were slaughtered at about 160 kg BW. The dietary treatment did not affect either the growth or slaughtering parameters of pigs. No significant differences were observed with respect to pH values, meat colour, loin composition and the iodine number of subcutaneous fat. Pigs on MA diets showed a significant (P < 0.01) improvement in DHA levels both in loin and in subcutaneous fat. No significant differences in relative fatty acid composition were observed between pigs receiving the MA supplement at the lower level (2.5 g kg^− 1) over an 8-week period (group B) and pigs receiving the higher MA supplement (5.0 g kg^− 1) over a 4-week period prior to slaughter (group C).     

稻鸭共生对稻田水生生物群落的影响

通过稻田共生的田间试验，对稻鸭共生稻田水体中的藻类植物和水生动物的种类、数量及生物量进行测定分析。结果表明：在水生生物种类组成上看，稻田水体中藻类植物共39属，水生动物共33属，都以对照为最高。藻类植物在数量上以对照为最高，为6.075×106ind/L，显著高于放鸭小区，在生物量上以放4只鸭为最高，但差异不显著。不同藻类构成比较分析，在数量上以硅藻、蓝藻和绿藻占优势，分别占个体总数的33.96%、29.45%和23.58%，在生物量以蓝藻和裸藻占优势，它们分别占总生物量的48.23%和26.72%，养鸭后绿藻的优势度下降，裸藻、蓝藻优势度上升。各类水生动物的数目和生物量均按水源区、对照区、少鸭区、多鸭区的顺序下降，但差异不显著。其数量上以原生动物优势，而生物量上以蚌虫占优势。在多样性方面，藻类植物以水源区和放4只鸭为最高，香农多样性指数都为2.03，水生动物多样性指数以放6只鸭为最高，香农多样性指数为1.765。可见，稻鸭共生增强了稻田生态系统的自然属性。     

藻类DNA条形码技术在藻类研究中的应用

DNA条形码技术是用一个短的DNA片段对物种进行快速的鉴定和识别.以往的研究主要选取线粒体、质体和核糖体的部分片段来进行分析,但藻的种类不同,DNA片段不同,结果也不同.文中主要介绍了藻类DAN条形码的研究状况,并总结了用于藻类DNAbarcoding研究的基因片段的特点及所存在的问题,为藻类DNA条形码的进一步深入研究提供参考.     

水动力循环复氧控藻技术在城市景观水体富营养化治理中的应用研究

在无锡蠡溪公园西苑水体中采用了水动力循环复氧控藻(HAAC)技术,研究了该技术对城市景观水体富营养化的处理效果。结果显示:在实施水动力循环复氧控藻(HAAC)技术的8个月期间,CODMn、TN、NH4+-N和TP平均去除率分别达到28.0%、35.7%、49.7%和37.0%;藻类叶绿素a平均去除率达40.2%,藻类总丰度平均下降率达56.0%,藻类群落从单一结构转变为多种优势种共存的结构。水华现象得到了有效控制,水体生态环境明显转好,处理期结束时西苑水体已达到IV类水标准。研究表明,水动力循环复氧控藻技术作为一种新型的水生态修复技术在城市景观水体富营养化治理工程中起到了很好的效果,值得推广应用。     

Comparison of wetland and agriculture drainage as sources of biochemical oxygen demand to the San Joaquin River, California

For many years, the San Joaquin River (SJR) has had low dissolved oxygen conditions intermittently during the late summer and early fall. The low dissolved oxygen conditions are impacting critical fish habitat and the SJR is being regulated under a state of California remediation plan that includes the development of a total maximum daily load (TMDL) allocation for oxygen demanding substances. In support of the development of a scientific TMDL allocation, studies are being conducted to characterize water quality in the many tributaries of the SJR. This study identified the sources of biochemical oxygen demand (BOD) in two western tributaries of the SJR, Mud Slough and Salt Slough, and measured the loads of BOD, algae, and ammonia entering the SJR from wetland and agricultural sources.

Mud and Salt Sloughs drain the Grassland Watershed. The watershed contains seasonal wetlands, irrigated farmland, and other agricultural lands. This drainage is under close regulatory scrutiny, because it produces a majority of the selenium and boron entering the SJR. In this study, wetland and irrigated agricultural drainage were sampled separately and a comparison was made to determine differences in water quality. In addition, water entering the study area was compared to water exiting the study area to determine the effect of water use in the region on water quality.

This study demonstrated that BOD loads from the Grassland Watershed to the SJR were proportional to flow during June–October, the most critical time for dissolved oxygen deficits in the lower SJR. This indicates that Mud and Salt Sloughs are not producing more BOD than other tributaries in the region that are not under close regulatory scrutiny. The BOD concentration of wetland drainage is higher than that of agricultural drainage, but the higher agricultural drainage flows result in a higher mass loading of BOD. Wetland flooding and irrigation of crops both had a negative impact on water quality. Algal growth was identified as the major source of BOD in agricultural drainage and locations where BOD control could potentially be implemented were identified.     

水中藻类污染物及其藻毒素分析方法研究进展

介绍了主要藻类污染物、藻毒素的性质及分类,论述了其危害,综述了水中藻类污染物及其藻毒素分析方法,分析了不同方法的优缺点。     

海洋植物组织培养技术研究进展

介绍国内外大型海藻组织培养的研究历史、概况、培养技术、相关研究及其应用前景,并阐述海藻取材、外植体无菌处理、培养基配制、培养条件、激素添加及藻体再生研究等问题。     

木薯新发藻斑病在中国的发生调查及病原鉴定

2010~2015年,笔者在对中国木薯主栽区的病害调查中发现了一种新的叶斑病。该病在云南、海南、广西、江西、福建等地区均有发生,生长中后期爆发流行,初步分析低温是该病成灾的关键因子。病原在叶片上形成黄褐色或黑褐色、近圆形、中央灰白色毛毡状的病斑,发病叶片大量脱落,严重影响木薯的长势和产量。对来自不同地区的病样进行显微观察。结果表明:病原在寄主组织上均形成有隔的孢囊梗,单生或丛生,其上着生数个圆形、黄色的孢子囊,表明其为寄生性头孢藻。     

藻类在黄龙钙华景观中的作用

藻类在地球及地球生命演化和物质循环过程中起到非常重要的作用,并以其独特的生理生态特性和强大的繁殖能力深刻影响着岩溶的形成与发育。在黄龙钙华景观的形成和发展过程中,藻类的着色作用,钙华沉积作用和钙华溶蚀作用是同步存在的作用体系,水体中的藻类为景观增添艳丽的颜色,藻类促进碳酸盐沉淀是重要的钙华生物成因。在外界环境发生改变的情况下,例如岩溶水缺乏时,藻类的着色作用与溶蚀作用会变得突出,大面积生长的蓝藻和生物侵蚀现象严重影响钙华景观的发育和观赏价值。笔者对钙华藻类在景观中作用的探讨为钙华景观的研究和保护提供了科学依据。