采用鱼外周血红细胞微核试验和紫露草微核试验综合评价水体污染

采用鱼外周血红细胞微核试验(Fish—MNT)和紫露草花粉母细胞徽核试验(Trad—MNT),联合检测了广西扶绥县肝癌高发区的水体污染。结果表明,塘水具有明显的诱变性。它可引起紫露草花粉母细胞和鱼外周血红细胞的微核率显著升高,提示塘水中存在的化学诱变物质,对动、植物细胞均具有潜在的基因毒性作用。Fish—MNT和Trad—MNT方法简便,结果鉴别客观、可靠,是判定水体综合诱变作用的有效的原位测定系统,值得推广应用。     

Multiple gonadotropin-releasing hormone (GnRH)-immunoreactive systems in the brain of the dwarf gourami,Colisa lalia: Immunohistochemistry and radioimmunoassay

The present study characterizes gonadotropin-releasing hormone (GnRH) neuronal groups that are located in several different brain regions by investigating GnRH molecular species and projection patterns in an anabantid fish, Colisa lalia. First, we examined the molecular species of GnRHs in extracts of the brain and the pituitary by reverse-phase high-performance liquid chromatography followed by radioimmunoassays. We found salmon GnRH (sGnRH), chicken GnRH-II (cGnRH-II), and an unfamiliar GnRH-like substance. Next, to examine the distribution of each GnRH molecule in different GnRH neuronal groups, we performed immunohistochemistry using four kinds of antisera and an antibody. Furthermore, we performed brain lesioning experiments of terminal nerve (TN) cells, the most conspicuous GnRH-immunoreactive cells in Colisa lalia. Comparisons of immunoreactive structures between TN-lesioned fish and untreated fish elucidated the projection area of each neuronal group. Three major neuronal groups were observed. TN-GnRH cells, which are located in the transitional area between the olfactory bulb and the telencephalon, showed strong sGnRH and weaker cGnRH-II immunoreactivity. TN-GnRH cells projected to wide areas of the central nervous system from the olfactory bulb to the spinal cord. The second group, located in the preoptic area, showed only sGnRH immunoreactivity and projected only to the pituitary. The third ond, located in the midbrain tegmentum, exhibited strong cGnRH-II and weaker sGnRH immunoreactivity. This cell group projected mainly to brain regions posterior to the hypothalamus and the spinal cord. These different projection patterns suggest functional differentiation of each GnRH neuronal group.     

Primary afferent projections to the central octavus nuclei in the elasmobranch, Rhinobatos sp., as demonstrated by nerve degeneration

Nerve degeneration studies were performed to determine the central projections of the octavus nerve in the guitarfish. Rhinobatos sp. Most first-order octavus nerve afferents are confined to the ventral longitudinal column of the medulla, which consists of four octavus nuclei: the nucleus octavus anterior (NOA), nucleus octavus magnocellularis (NOM), nucleus octavus descendens (NOD); and nucleus octavus posterior (NOP). Central projections of the octavus nerve outside of the ventral octavus nuclear column are to the vestibulolateral lobe of the cerebellum, the large multipolar cells that lie deep to the cerebellar crest of nucleus intermedius, the reticular formation, and the nucleus octavolateralis efferens. In addition, the cytoarchitectural features of the four octavus nuclei have been analyzed: the NOA consists of large spindle-shaped neurons and medium-sized multipolar neurons; the NOM is a small nucleus consisting of very large multipolar neurons; the NOD contains several types of neurons including large spindle-shaped neurons, large multipolar neurons, and polymorphic small and medium-sized neurons; and the NOP contains small spherical and small multipolar neurons evenly distributed throughout the nucleus. On the basis of the morphology of the neurons, the NOA and NOD appear to have subdivisions suggesting a more complex organization of the octavus nuclear column than previously recognized.     

GABA- and glycine-immunoreactive neurons in the spinal cord of the carp,Cyprinus carpio

γ-Aminobutyric acid (GABA) and glycine are the two main inhibitory transmitter amino acids in the central nervous system of vertebrates. The distribution of cells containing GABA and glycine in the carp spinal cord was examined by using specific antisera raised against the two amino acids conjugated to bovine serum albumin. The immunoreaction on serial paraffin sections was visualized by a streptavidin-biotin method. Both antisera gave highly specific labellings of cells. At least three types of GABA-immunoreactive cells were found. They were small cells in the dorsal grey matter, various sized cells in the central and ventral grey, and some ependymal cells contacting the central canal. In addition, very small cells and neuropil structures in the dorsal horn were strongly immunoreactive to the GABA serum. Certain cells in the ventral horn have moderate numbers of labelled synaptic boutons on the perikarya, but very few GABA-labelled terminals were found on putative motoneurons. The immunoreactive ependymal cells appeared to have a ventrolaterally directed axon. The glycine antiserum labelled small and intermediate cells in the dorsal grey, large, elongated cells in the median region, and varying sized cell sin the ventral grey. The numbers and density of immunoreactive cells and neuropil strucures in the ventral horn were fewer and lower than in GABA-stained sections. The median large cells had a thick venrolateral process. The ventral intermediate cells were often found near putative motoneurons. Labelled synaptic boutons were present on most ventral cells including putative motoneurons and interneurons. Abundant distribution of cells immunoreactive to both antisera suggest important roles of both GABA and glycine as neurotransmitters for controlling swimming movements in teleosts. © 1993 Wiley-Liss, Inc.     

Occupational protein contact dermatitis from herring

We present a case of occupational protein contact dermatitis caused by herring in a dolphinarium worker. The in vivo and in vitro tests results indicated a type I allergic mechanism. In vivo cross-reactivity among fish belonging to the Clupeiformes order was observed.     

高效液相色谱法分离测定鱼油中的EPA和DHA

介绍用高效液相色谱法分离测定鱼鱼油及其制品中的二十碳五烯酸（ｅｉｃｏｓａｐｅｎｔａｅｎｏｉｃａｃｉｄ，ＥＰＡ）和二十二碳六烯酸（ｄｏｃｏｓａｈｅｘａｅｎｏｉｃａｃｉｄ，ＤＨＡ）方法。使用Ｗａｔｅｒｓ液相色谱仪，μ－ＢｏｎｄｐａｒｋＣ＿（１８）Ｈ＿（３７）填充柱（３０ｃｍ×４ｍｍ）。鱼油经０．５ｍｏｌ／ＬＫＯＨ乙醇溶液皂化，三乙胺－ω－溴苯乙酮酯化后直接进样。以８８％的甲醇水溶液为流动相，紫外２５４ｎｍ检测，用外标法测定。该方法的回收率ＥＰＡ为９３．０％～９８．０％，ＤＨＡ为９３．０％～１００．０％。相对标准偏差ＥＰＡ为０．４１％～０．８６％，ＤＨＡ为０．６７％～１．２０％（ｎ＝７）。本法简便、快速、重现性好。     

鱼油豆油对大鼠线粒体磷脂脂肪酸组成的影响

方法：大鼠分别饲以低硒和补硒饲料３０天，补加油类之后（５０ｇ／ｋｇ饲料）继续饲养３０天。结果：线粒体膜磷脂中脂肪酸组成可反映大鼠饮食中脂肪酸的组成，磷脂酰胆碱（ＰＣ）和磷脂酰乙醇胺（ＰＥ）中Ｃ２０∶５和Ｃ２２∶６含量鱼油组明显高于豆油组，而且鱼油中Ｃ２２∶６比Ｃ２０∶５优先结合掺入磷脂中。ＰＣ中Ｃ２０∶４豆油组明显高于鱼油组。ω６／ω３比值降低。豆油和鱼油均使线粒体Ｃａ２＋－ＡＴＰａｓｅ活性下降，但对线粒体钙有不同的影响。补硒对脂肪酸组成，Ｃａ２＋－ＡＴＰａｓｅ影响不大，但加速钙的释放。结论：鱼油具有防治心血管疾病的作用，其作用基础可能在于Ｃ２０∶５和Ｃ２２∶６掺入细胞膜磷脂中，影响了脂肪酸组成，并对其功能产生影响     

Structural and functional impairment of the hypothalamo- pituitary-interrenal axis in fish exposed to bleached kraft mill effluent in the St Maurice River,Quebec

The effects of bleached kraft mill effluent (BKME) on blood cortisol levels and the morphology of the pituitary-interrenal axis were investigated in two species of teleost fish, the northern pike, Esox lucius, and the yellow perch, Perca flavescens, sampled upstream and downstream from a pulp and paper mill on the St Maurice River, Quebec. Fish were acutely stressed by a standardized capture and sampling protocol at both sites, and their ability to elevate blood cortisol levels in response to the capture stress was compared. Blood cortisol levels in fish from the upstream site (>100 ng/ml plasma) were higher than the levels in fish from the BKME site, and the pituitary corticotropes and the interrenal steroidogenic cells of the upstream fish were larger and had larger nuclei compared with cells from the downstream fish. The low blood cortisol levels in fish exposed to BKME were correlated to cellular atrophy within the hypothalamo-pituitary-interrenal (HPI) axis. The reduced ability to elevate blood cortisol in response to an acute stress may be an endocrine dysfunction occuring in fish chronically exposed to chemical stressors in their environment     

CAN WE RECOMMEND FISH OIL FOR HYPERTENSION?

1. The ability of the n-3 fatty acids in fish oil to lower blood pressure has been established. Dietary fish oil supplementation is effective in mild hypertension and, in certain cases, as an adjunct therapy in drug-treated hypertension. Efficacy may be enhanced by restricting sodium intake. 2. The overall benefit of fish oil in hypertension, however, has not yet been fully evaluated. We still need further information on the relative efficacy of individual omega-3 fatty acids and on additional cardiovascular benefits and possible disadvantages of increasing their consumption.     

Identification of horizontal cells generating different spectral responses in the retina of a teleost fish (Eugerres plumieri)

Six different types of spectral responses were recorded from horizontal cells under mesopic conditions in perfused retina, isolated from the dark-adapted mojarra (Eugerres plumieri). They were tentatively termed photopic Lr-, Lg1-, Lg2-, Lb-, and C-type, and scotopic L-type. The Lr-, Lg-, and Lb-type responses showed a maximum peak at 605, 550, and 516 nm respectively, while the C-type was composed of hyperpolarizing potentials in response to shorter wavelengths and depolarizing potentials in response to longer wavelengths (so-called R/G-type). The scotopic L-type has a peak at 516 nm in the spectral response and a slow decay phase in the waveform response. Following a brief period of diffuse illumination, it was found that the Lg1-type response is altered to the Lr-type, while both Lg2- and Lb-type responses change to the C-type. Intracellular marking with Lucifer or Procion yellow identified the cellular origins of different response types: external (He) and medial horizontal (Hm) cells for the Lr-type, internal horizontal (Hi) cells for the C-type, and rod-horizontal (Hr) cells for the scotopic L-type. Only He cells were found to possess an axon, while dye coupling was seen between axonless Hm, Hi, or Hr cells but not between He cells. The morphology of these fluorescent dye-marked cells was the same as that of the respective cells observed in Golgi-stained materials.