Pathology of mixed infections of saprolegniasis-myxosporidiosis in Indian major carp (Catla catla Ham.)

An outbreak of saprolegniasis in Catla catla in composite carp culture ponds were recorded during winter season. The typical cotton wool growths were observed on whole body surfaces of catla along with sporadic mortality. The fungal invasion was only restricted to skin and no fungal elements were visible in any internal organs after periodic acid schiff staining. On histology, periportal accumulation of mononuclear cells in liver, presence of myxosporidean cysts in antieror kidney, eosinophilic granular cells reaction in submucosa of stomach and intestine, dilated and engorged blood vessels of brain along with sloughing of epidermis and hyperplasia at gill lamellar base were pronounced changes. The possible role of release of Saprolegnia toxin in producing internal organs pathology has been discussed.

大豆（Glycine max (L)Merr.）叶片和非叶器官光合特性探讨

本论文由三部分组成，一、大豆高产品种黑农40与低产品种黑农37不同发育时期叶片光合功能的比较研究。二、大豆非叶器官豆荚的光合特性。三、不同大豆品种叶片和非叶器官光合特性的比较分析。 一、 黑农40和黑农37不同发育时期叶片的光合特性。 以不同产量水平的东北大豆黑农40和对照品种黑农37为试验材料，研究了从幼苗期到衰老期五个不同发育时期叶片光合作用特性的变化。尤其是比较系统地研究了C4途径的表达，并通过相关分析，发现C4途径酶的活性与大豆的光合效率及其产量密切相关。主要研究结果如下： 1．测定不同发育时期大豆叶片净光合速率、DCIP光还原活力和1,5-二磷酸核酮糖羧化酶(RuBPcase)活力，结果表明，黑农40和黑农37叶片净光合速率均在初荚期达到最高值，而且不同发育时期的黑农40叶片光合能力均强于黑农37。 2．随着大豆叶片的发育和衰老，其叶绿素、类胡萝卜素的含量及Chla/b比值有一个逐渐升高，而后降低的过程。在同一发育时期，高产高光效品种黑农40光合色素含量均高于黑农37，有助于黑农40捕获更多的光能供光合作用所利用。 3．叶绿体吸收光谱及四阶导数光谱表明在整个生育期内以初荚期叶片对光能的吸收能力最强;而每一个发育时期黑农40叶片对光能吸收的能力均比黑农37高。荧光动力学参数表明，高产大豆黑农40叶片PSII活性(Fv/Fo)，光化学猝灭系数(qP)及PSII总的光化学量子产量也均高于对照品种黑农37的相应值：而黑农40的非光化学猝灭系数(qN)低于黑农37。说明高产大豆叶片具有与产量潜力相关的较高光能吸收和原初转化能力。通过对叶片及其叶绿体低温(77K)荧光发射光谱特性的分析表明，黑农40叶绿体对两个光系统之间激发能的调节能力优于黑农37。总之，黑农40对光能的吸收、传递和转化能力高于黑农37，从而能为碳同化提供更多能量。 4．通过研究苗期、开花期、初荚期、鼓粒期和衰老期等发育阶段的黑农40和黑农37叶片中磷酸烯醇式丙酮酸羧化酶(PEPCase)、NADP-苹果酸脱氢酶(NADP-MDH)、NADP-苹果酸酶(NADP-ME)、丙酮酸磷酸双激酶(PPDK)等C4途径的关键酶的活性变化，结合同位素14CO2喂饲试验，证明两种大豆叶片均含有C4途径四种关键酶，其原初产物含有有限的有机酸，说明有C4循环存在;而从PEPCase/RuBPcase的比值看，C4途径的酶在黑农40叶片中表达较高。通过相关分析，我们发现Pn与PSII光化学活性，RuBPCase及C4酶活性密切相关。这些结果还暗示有可能通过检测C4途径酶的表达水平及比例，筛选出具有高产潜力的大豆种质。 二、大豆非叶器官豆荚的光合特性。 通过对大豆非叶器官豆荚光合特性的研究，结果表明大豆豆荚的光合能力在鼓粒期达到最高值。通过叶绿体吸收光谱、荧光动力学和低温荧光等测定技术，我们发现鼓粒期的豆荚对光能的吸收、传递和转化有更高的能力;在鼓粒期不同品种的豆荚色素的含量也较高，从而有利于捕获更多的光能，供光合作用利用。DCIP光还原活力的测定结果表明鼓粒期豆荚也具有较高光合能力。 通过对大豆的初荚期、鼓粒期和衰老期豆荚RuBPCase和四种C4途径酶活性的研究，不仅证明非叶器官中有高活性的C4途径酶和存在有限的C4途径，而且鼓粒期豆荚有较高的碳同化效率。 三、不同大豆叶片和非叶器官光合特性的比较分析。 对三种大豆叶片、豆荚、种皮和子叶的色素含量和Chla/b进行测定，利用光谱技术、荧光技术及RuBPCase活性的测定，分析了大豆不同器官的光合特性。试验结果证明，非叶器官具有与叶器官相似的光合性能。与叶片比较，表明在非叶器官中具有非常高的C4酶活性。有利于补偿叶片开始衰老光合作用衰退的不足，因此非叶器官的这些光合特性有助于增加大豆光合产物的积累。

Effect of combined thyroxine and cortisol treatment on hatching of eggs, post-embryonic growth and survival of larvae of Heteropneustes fossilis

In order to record the effects of thyroxine and cortisol (individual/combined) on hatching, post-embryonic growth and survival of larvae of Heteropneustes fossilis, newly fertilized eggs were given bath immersion treatments of L-thyroxine (T sub(4); 0.05 mg/l), cortisol (0.50 mg/l) and T sub(4)+ cortisol (0.05 mg/l+0.50 mg/l) for 15 days. Hatching of eggs, growth and survival of the larvae improved significantly (P<0.001) in the hormone treated groups as compared to those of control. The frequency of deformities was reduced in the combined hormone treatment group. The present observations suggest that the advanced digestive function probably induced by T sub(4)+cortisol treatment might have resulted in improvement in food utilization during the critical phases of first feeding and promoted vital developmental processes resulting in uniform growth, decreased mortality, better survival and transformation of larvae to juveniles. This combined hormone therapy appears to have practical utility in fish hatchery practice for better success in larval rearing.

A preliminary study for establishing Perna viridis (Mollusca:Bivalvia) as a biological monitor for pollution in Karachi coastal water

Adverse effects of toxic substances on the environmental quality have become a subject of concern in recent years. Toxicity of heavy metals has never been in dispute and therefore their presence in our natural environment is undesirable. This study was undertaken to establish the capability of Perna viridis as a monitor for pollution in the Manora channel. Accumulation of Zinc, Copper, Iron and Manganese by marine mussels, sampled from Manora channel, was determined. Metal load varied markedly between individuals from the same populatin. This variability was partly accounted for systematic relationship between metal load and body weight and age. The distribution of metal between the major organs was considered, but the analysis of separate organs showed no advantage for their use as a biological monitor. comparison between Iron, Manganese, Copper and Zinc concentration in ambient sea water and in the mussel showed no clear correspondence. The results suggest that the mussel is capable of acting as a biological monitor, although may not be a good short term monitor of Iron, Manganese, Zinc and Copper. It may have potential as a long term and site comparison monitor for metals, once inherent variability is taken into account

Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

We transplanted kidneys from alpha 1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GaIT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GaIT-KO pigs to humans.

Dynamics of parasite population and its histopathological and histophysiological effects in the stomach of a freshwater fish

The caryophyllaeid cestode Lytocestoides fossilis infects the freshwater catfish Heteropneustes fossilis. The study was conducted for two consecutive years (2004-06) to record the bio-statistical data of the parasite. The incidence, intensity, density and index of infection of the parasite have been recorded. The infection was more during June to September, moderate during February to May and low during October to January. The parasite brought about severe histopathological changes in the stomach of infected fish. The changes observed in the stomach of fish included structural damage of the villi, inflammation, and fibrosis associated with hyperplasia and metaplasia. The hypertrophy of mucous layer led to vacuolation and necrosis. Histochemical changes were noticed with enhanced carbohydrate, protein and lipid contents. The enhanced substrate content in the infected organ might be due to the disfunctioning of the digestive tract, which results in the accumulation of various metabolites. Mucus secretion was triggered as a protective interaction against parasitic invasion. The parasitic infection affects the general metabolic state of the host and as the result, the fish becomes sluggish and moribund.

Health and disease status of Thai pangas, Pangasius hypophthalmus cultured in rural ponds of Mymensingh, Bangladesh

Thai pangas, Pangasius hypophthalmus is one of the important aquaculture species in Bangladesh. Over the last few years spectacular development has been taking place in Thai pangas farming in Mymensingh district. Due to availability of easy breeding and culture techniques as well as quick return, more and more people are converting their rice fields into pangas farms overnight. The present study was carried out to examine health and disease status of Thai pangas mainly through clinical, histopathological and bacteriological techniques. In addition, for collecting primary data on disease and health status of Thai pangas and the resultant socioeconomic impacts on rural households, questionnaire interview and participatory rural appraisal tools were used with selected farming households in three upazilas of Mymensingh district. The most prevalent diseases as reported by the farmers were red spot, followed by anal protrusion, tail and fin rot, pop eye, dropsy and gill rot. Other conditions like cotton wool type lesion, ulceration and white spot were reported but with lower incidence. Four isolates of Aeromonas hydrophila were recovered from kidney and lesion of diseased fish. Hemorrhage over the body especially near mouth and caudal region was noticed in the fishes associated with aeromonad infection. Internally, kidney, liver and spleen became swollen and enlarged. The isolates varied with their pathogenicity. All the four isolates were sensitive to Nitrofurantoin, Cotrimoxazole and Tetracycline but were resistant to Amoxycilline. An attempt was made to treat diseased fish with extracts from neem leaf, garlic and turmeric. Recovery of infection was monitored through mortality and histopathology. General histopathological changes of different organs were also studied. Extract from neem (Azadirachta indica) leaf gave better result. Telangiectasis, lamellar hypertrophy and hyperplasia hemorrhage, lamellar fusion, necrosis of lamellar epithelial cells, presence of parasites and their cysts were the major pathology of gills. Hemorrhagic lesion, pyknotic nuclei and melanomacrophage centers (MMC) were found in the liver of fish. Major pathologies in kidney of fish included presence of MMC, necrotic and ruptured kidney tubules, severe haemopoietic necrosis, and hemorrhage. The economic loss due to disease in Thai pangas farming was estimated from the difference between expected production and actual production. On an average, Thai pangas farmers of Mymensingh incur a loss of Tk. 23,104/ha/cycle due to fish disease (3.6% of expected total production). The loss, however, varied with location and size of farms, type of farmers and management practices. The study also highlighted fish health management related problems and recommended further work for the development of user-friendly farmer-oriented fish health management packages.

Distribution of vitamin B-12 in some fishes and marine invertebrates

Distribution of vitamin B-12 in the skeletal muscle of several marine and fresh water fish and marine invertebrates are reported. The vitamin B-12 content of white muscle of various fish ranges between 0.05 and 1.5 micrograms. The elasmobranch fish, such as sharks and rays, has a lower levels of vitamin B-12. The distribution of vitamin B-12 in the red muscle, heart, brain and liver of various fish is also shown. Content in red muscle varies between 3 and 22 micrograms, averaging 8 micrograms. The values show that the heart is a rich source of vitamin B-12. Internal organs are also rich in vitamin B

Distribution of 5'-nucleotidase activity in the tissues of a freshwater teleost, Ophicephalus striatus Bloch

Homogenates of tissues have been analysed for the presence of 5'-nucleotidase activity. Sexes are not treated individually since no significant differences were observed. All organs showed marked activity, the highest being in the cardiac tissues, then the kidney, spleen, brain, and low values in the liver and muscles. Comparison with data from other fish studied shows a marked difference between O. striatus and O. punctatus.

Distribution of heavy metals in the northern shrimp Pandalus borealis from the Oslofjord

Studies on the distribution of heavy metals like copper, cadmium, zinc, lead and mercury in deep sea prawns Pandalus borealis in the Oslofjord region showed that those collected from inner and middle fjord contained higher levels of heavy metals than those from the outer fjord. Their content in the edible portions, viz., tail muscle, was less compared to other organs. In terms of metal concentration copper and zinc are present in significant quantities in Pandalus borealis.

Digestion of selected foods by Yunnan snub-nosed monkey Rhinopithecus bieti (Colobinae)

Three digestion trials were conducted to quantify aspects of digestive physiology in the Yunnan snub-nosed monkey Rhinopithecus bieti, a foregut fermenter that feeds primarily on lichens. Mean retention time (MRT, the average time plastic markers spent in

The unusual adaptive expansion of pancreatic ribonuclease gene in carnivora

Pancreatic ribonuclease (RNASE1) is a digestive enzyme that has been recognized to be one of the most attractive model systems for molecular evolutionary studies. The contribution of RNASE1 gene duplication to the functional adaptation of digestive physio

A Profound Role for the Expansion of Trypsin-Like Serine Protease Family in the Evolution of Hematophagy in Mosquito

The trypsin-like serine protease (Tryp_SPc) family is ubiquitous in animals and plays diverse roles, especially in the digestive system, in different phyla. In the mosquito, some Tryp_SPc proteases make important contributions to the digestion of the bloo