ナンキョクサン ノ サカナ Notothenia neglecta Nybelin (ノトセニア カ) モウマク ノ ヒカリ ジュヨウ サイボウ ト シキソ ジョウヒ ノ ビサイ コウゾウ

南極産の魚Notothenia neglectaはキングジョージ島, アドミラルティ湾の生息域では優先的に出現する魚である。本種は捕食者であり, しばしば, 正確な視覚を用いた待ち伏せ採餌を行う。そこで網膜の光受容細胞と色素上皮の微細構造を電子顕微鏡を用いて解析することとした。網膜には色素上皮と桿体, 短い独立型錐体, 長い独立型錐体, 不等双子型錐体, 三子型錐体の5種の光受容細胞とニューロン, 支持細胞が存在する。色素上皮はたたみ込まれた基底膜, 基底ミトコンドリア, 平滑な網状体, 大量の微小管, メラニン顆粒, 食作用胞, 光受容細胞の剥離膜で特徴づけられている。錐体には外節の二重膜状板, 楕円体・筋様体の副錐体, 連結繊毛, 微絨毛が, 楕円体中には中心小体, そして筋様体・楕円体域には掌状筋様体, ミューラー細胞の頂上微絨毛が存在する。これら総ての状態は, N. neglectaに環境の光条件の変化に対するあらゆる種類の適応を可能にし, N. neglectaを, 水平, 垂直方向に調整可能な10層に配置された細胞を持つという, 複雑な網膜を備える魚類の1種としている。このことが, 周年, 充分な視覚による行動と餌と環境との認知を可能にしているのである。The Antarctic nototheniid Notothenia neglecta is the dominant fish in its habitat in Admiralty Bay, King George Island. They are predators, often ambush feeders, with accurate visual behaviour. For that reason, the ultrastructure of retinal photoreceptive cells and the pigment epithelium was analysed through electron microscopy. Their retina has a pigment epithelium, five different photoreceptors : rods, short single, long single, double, and triple cones, and neurones and support cells. The pigment epithelium is characterised by infoldings of the basal membrane, basal mitochondria, smooth reticule, large amount of microtubules, melanin granules, phagosomes and detached membranes of photoreceptors. Cones show bimembranous discs in the outer segment, an accessory outer segment, a connecting cilium, calycal processes, microtubules in the inferior ellipsoid and myoid, centrioles in the ellipsoid, interdigitating myoid fins and apical microvilli of Muller cells in the myoid and elliposid region. All these features allow all sorts of adaptations to the environmental photic variations, and situate N. neglecta among fish with a complex retina, with cells that are arranged in ten layers, allowing horizontal and vertical integration among them. This allows optimal visual behaviour and perception of food and environment in every Antarctic season

ナンキョクサンギョ ハゲギスTrematomus newnesi Boulenger ノ エドウブツ ハッケン ト サイエ コウドウ カイシ ニ サイシテ シカク ノ ハタス ジュウブンナ ヤクワリ

ノトセニア科に属する南極産魚ハゲギス, Trematomus newnesi BOULENGERの餌動物発見機能を理解するために, 視覚刺激実験を行った。1997-98年夏期に, サウスシェトランド諸島, キングジョージ島, アドミラルティ湾において, 大小21尾ずつの2群, 計42尾を採取した。実験は環境条件制御をした水槽を用いて行った。光条件は22時間の明期, 2時間の暗期とした。視覚刺激の評価をするために, 餌動物として2種の端脚類, Gondogeneia antarcticaとWaldeckia obesa, それにナンキョクオキアミEuphausia superbaを透明な容器に入れた上で, 水槽に入れた。化学的刺激を与えないように, 餌動物を入れた容器の水と魚が入った容器の水との接触が起こらないようにした。各実験とも, 供試魚の42.3%が刺激に対して反応した。端脚類は18cmの距離から, またナンキョクオキアミは22.5cmの距離から発見された。給餌つまり視覚刺激を与えてから, 最初の行動が起こるまでの時間差は17.7秒であり, 刺激は実験時間30分の51.5%の間持続した。30分の観察時間中に端脚類を攻撃したのは平均20.9回で, "いじめ"を完了した回数は平均9回であった。また, ナンキョクオキアミを攻撃したのは平均28.3回で, 平均12.6回が"いじめ"を完了した。最高値は常に実験開始から10分以内で起こった。刺激に対する反応状態は, 実験の前半に有意に高かった。視覚刺激によって引き起こされる一連の能動的行動が明らかになった。ハゲギスの網膜はニューロンと, 餌動物発見の重要な手段となる正確な像を結ばせる4型の光受容細胞からなる複合基質であり, 化学的, 機械的刺激を欠いても, 十分に摂餌行動を惹き起こすことができる。In order to improve the understanding of food detection mechanisms in the Antarctic nototheniid fish Trematomus newnesi BOULENGER, visual stimulation was tested. During the Antarctic summer of 1997/98,42 individuals, 21 belonging to each of two size classes, were obtained in Admiralty Bay (King George Island, South Shetlands). Fish tests were undertaken in aquaria maintained under controlled environmental conditions and a photoperiod of 22 hours light and 2 hours darkness. For the evaluation of visual stimulation, two species of amphipods, Gondogeneia antarctica and Waldeckia obesa, and the krill Euphausia superba, were offered as prey inside a transparent container in each aquarium. No contact was established between the water with prey and the water with predators, to avoid chemical stimulation. In each test 42.3% of the individuals reacted to the stimulation. Amphipods were detected from a distance of 18cm and krill from 22.5cm. The time lapse between food offer and the first reaction after visual stimulation was 17.7s and the stimulation lasted for 51.5% of the experimental time (30 min). During 30min of observation a mean of 20.9 attacks and 9.0 persecutions were performed against amphipods and 28.3 attacks and 12.6 persecutions against krill. The highest values were always obtained within the first 10 min of the test. The duration of the state of stimulation was significantly higher in the first half of the daylight period. A sequence of attitudes that result from positive visual stimulation was defined. The retina of T. newnesi is a complex matrix with neurones and four types of photoreceptors cells allowing accurate vision, which is an important tool for food detection, being sufficient to elicit feeding behaviour even in the absence of chemical and mechanical stimulation

Ultrastructure of photo-sensory cells and pigment epithelium in the retina of the Antarctic fish Notothenia neglecta Nybelin (Nototheniidae)

The Antarctic nototheniid Notothenia neglecta is the dominant fish in its habitat in Admiralty Bay, King George Island. They are predators, often ambush feeders, with accurate visual behaviour. For that reason, the ultrastructure of retinal photoreceptive cells and the pigment epithelium was analysed through electron microscopy. Their retina has a pigment epithelium, five different photoreceptors : rods, short single, long single, double, and triple cones, and neurones and support cells. The pigment epithelium is characterised by infoldings of the basal membrane, basal mitochondria, smooth reticule, large amount of microtubules, melanin granules, phagosomes and detached membranes of photoreceptors. Cones show bimembranous discs in the outer segment, an accessory outer segment, a connecting cilium, calycal processes, microtubules in the inferior ellipsoid and myoid, centrioles in the ellipsoid, interdigitating myoid fins and apical microvilli of Muller cells in the myoid and elliposid region. All these features allow all sorts of adaptations to the environmental photic variations, and situate N. neglecta among fish with a complex retina, with cells that are arranged in ten layers, allowing horizontal and vertical integration among them. This allows optimal visual behaviour and perception of food and environment in every Antarctic season

Visual Sufficiency in food detection and initiation of feeding behaviour in the Antarctic fish Trematomus newnesi Boulenger

In order to improve the understanding of food detection mechanisms in the Antarctic nototheniid fish Trematomus newnesi BOULENGER, visual stimulation was tested. During the Antarctic summer of 1997/98,42 individuals, 21 belonging to each of two size classes, were obtained in Admiralty Bay (King George Island, South Shetlands). Fish tests were undertaken in aquaria maintained under controlled environmental conditions and a photoperiod of 22 hours light and 2 hours darkness. For the evaluation of visual stimulation, two species of amphipods, Gondogeneia antarctica and Waldeckia obesa, and the krill Euphausia superba, were offered as prey inside a transparent container in each aquarium. No contact was established between the water with prey and the water with predators, to avoid chemical stimulation. In each test 42.3% of the individuals reacted to the stimulation. Amphipods were detected from a distance of 18cm and krill from 22.5cm. The time lapse between food offer and the first reaction after visual stimulation was 17.7s and the stimulation lasted for 51.5% of the experimental time (30 min). During 30min of observation a mean of 20.9 attacks and 9.0 persecutions were performed against amphipods and 28.3 attacks and 12.6 persecutions against krill. The highest values were always obtained within the first 10 min of the test. The duration of the state of stimulation was significantly higher in the first half of the daylight period. A sequence of attitudes that result from positive visual stimulation was defined. The retina of T. newnesi is a complex matrix with neurones and four types of photoreceptors cells allowing accurate vision, which is an important tool for food detection, being sufficient to elicit feeding behaviour even in the absence of chemical and mechanical stimulation

Cellular Structural Changes in Candida albicans Caused by the Hydroalcoholic Extract from Sapindus saponaria L.

Vulvovaginal candidiasis (VVC) is a disease caused by the abnormal growth of yeast-like fungi in the mucosa of the female genital tract. Candida albicans is the principal etiological agent involved in VVC, but reports have shown an increase in the prevalence of Candida non-C. albicans (CNCA) cases, which complicates VVC treatment because CNCA does not respond well to antifungal therapy. Our group has reported the in vitro antifungal activity of extracts from Sapindus saponaria L. The present study used scanning electron microscopy and transmission electron microscopy to further evaluate the antifungal activity of hydroalcoholic extract from S. saponaria (HE) against yeast obtained from VVC and structural changes induced by HE. We observed the antifungal activity of HE against 125 vaginal yeasts that belonged to four different species of the Candida genus and S. cerevisae. The results suggest that saponins that are present in HE act on the cell wall or membrane of yeast at the first moments after contact, causing damage to these structures and cell lysis

Guanosine promotes B16F10 melanoma cell differentiation through PKC-ERK 1/2 pathway

Malignant melanoma is one of the most lethal cancers. Nowadays, several anti-melanoma therapies have been employed. However, the poor prognosis and/or the increased toxicity of those treatments clearly demonstrate the requirement of searching for new drugs or novel combined chemotherapeutic protocols, contemplating both effectiveness and low toxicity. Guanosine (Guo) has been used in combination with acriflavina to potentiate the latter`s antitumor activity, through still unknown mechanisms. Here, we show that Guo induces B16F10 melanoma cell differentiation, attested by growth arrest, dendrite-like outgrowth and increased melanogenesis, and also reduced motility. A sustained ERK 1/2 phosphorylation was observed after Guo treatment and ERK inhibition led to blockage of dendritogenesis. Intracellular cyclic AMP was not involved in ERK activation, since its levels remained unchanged. Protein kinase C (PKC), in contrast to phospholipase C (PLC), inhibition completely prevented ERK activation. While the classical melanoma differentiation agent forskolin activates cAMP-PKA-Raf-MEK-ERK pathway in B16F10 cells, here we suggest that a cAMP-independent, PKC-ERK axis is involved in Guo-induced B16F10 differentiation. Altogether, our results show that Guo acts as a differentiating agent, with cytostatic rather than cytotoxic properties, leading to a decreased melanoma malignancy. Thus, we propose that Guo may be envisaged in combination with lower doses of conventional anti-melanoma drugs, in an attempt to prevent or diminish their adverse effects. (c) 2008 Elsevier Ireland Ltd. All rights reserved

A shorter fixation protocol for transmission electron microscopy: An alternative to spend less time

The performance of a moderately shorter fixation protocol for transmission electron microscopy (TEM) was evaluated by analyzing the cell structure quality after the processing. The relevance of this experimental technique is mainly based on reducting time of the steps of conventional protocols: fixation, washes, dehydration, and epoxy resin infiltration. Two sources of murine cells were used, the peritoneal and mesenteric lymph node cells. A fixation and material processing faster than usual methods can save time and improve results. Samples analysis indicated good preservation of different cell structures and organelles after this protocol

Metabolic responses of the Antarctic fishes Notothenia rossii and Notothenia coriiceps to sewage pollution

Made available in DSpace on 2019-09-12T16:53:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2015Ministério do Meio Ambiente (MMA)Ministério da Ciência, Tecnologia e Inovação (MCTI)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Secretariat of the Inter-ministerial Commission for the Resources of the Sea (SeCIRM)Instituto Nacional de Ciência e Tecnologia Antártico de Pesquisas Ambientais (INCT-APA)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)The present study aimed to assess the sewage effects of the Brazilian Antarctic Station Comandante Ferraz, Admiralty Bay, King George Island, on the hepatic metabolism (energetic, antioxidant, and arginase levels) and levels of plasma constituents of two Antarctic fish species Notothenia rossii and N. coriiceps. The bioassays were conducted under controlled temperature (0 degrees C) and salinity (35 psu), exposing the fish for 96 h, to sewage effluent diluted in seawater to 0.5 % (v/v). Liver homogenates were tested for the specific activities of the enzymes glucose-6-phosphatase (G6Pase), glycogen phosphorylase (GPase), hexokinase, citrate synthase, lactate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, superoxide dismutase, glutathione reductase, catalase, and arginase. Plasma levels of glucose, triacylglycerides, cholesterol, total protein, albumin, chloride, magnesium, calcium, and inorganic phosphate were also determined. In N. rossii, the decrease in citrate synthase and the increase in G6Pase and GPase suggested that the sewage effluent activated glycogenolysis and hepatic gluconeogenesis, whereas is N. coriiceps, only G6Pase levels were increased. In N. rossii, sewage effluent induced hypertriglyceridemia without modulating glucose plasma levels, in contrast to N. coriiceps, which developed hypoglycemia without elevating plasma triglyceride levels. The decrease in glutathione reductase levels in N. coriiceps and in superoxide dismutase and catalase in N. rossii suggest that these two species are susceptible to oxidative stress stemming from the production of reactive oxygen species. An increase in magnesium in N. rossii and a decrease in N. coriiceps showed that sewage effluent compromised the control of plasma levels of this cation. Although phylogenetically close, both species of Antarctic fish exhibited different metabolic responses to the sewage effluent, with N. coriiceps showing greater susceptibility to the toxic effects of the pollutants. The present study suggests that the biochemical responses of these two species are potential indicators of metabolic changes caused by sewage effluents.[Rodrigues, Edson, Jr.; Feijo-Oliveira, Mariana; Kawagoe Suda, Cecilia Nohome; Vani, Gannabathula Sree; Rodrigues, Edson] Universidade de Taubaté (Unitau), Inst Basic Biosci, BR-12030180 Taubate, SP, Brazil[Donatti, Lucelia] Univ Fed Parana, Dept Cell Biol, BR-81530130 Curitiba, PR, Brazil[Lavrado, Helena Passeri] Univ Fed Rio de Janeiro, Dept Marine Biol, BR-21941902 Rio De Janeiro, RJ, Brazi