Anatomy of the Nauplii of Oithona ovalis Herbst (Copepoda, Cyclopoida)

Foram estudados 6 estágios naupliares do ciclopóide Oithona ovalis Herbst 1955obtidos na n atureza ou criados em laboratório.Os náuplios vivos e as preparações histológicas foram observadas e descritas,a anatomia interna, o funcionamento de alguns órgãos e as mudanças que ocorreram durante o desenvolvimento naupliar. Atenção especial foi dispensada à musculatura e ao aparelho digestivo

The scope of science for the International Polar Year, 2007-2008

The International Polar Year 2007““2008 will be the largest internationally coordinated research programme in 50 years. It will be an intensive period of interdisciplinary science focused on the Arctic and the Antarctic. IPY 2007““2008 research activities were assembled from the ideas of researchers in more than 60 countries. A total of 228 projects have been endorsed by the ICSU/WMO Joint Committee for IPY 2007““2008. These projects have a strong interdisciplinary emphasis and address the six themes as well as education and outreach objectives. IPY projects will exploit new technological and logistical capabilities and strengthen international coordination of research. They aim to attract, engage and develop a new generation of researchers and raise the awareness, interest and understanding of polar residents, educators, students, the general public and decision makers worldwide. IPY projects will collect a broad-ranging set of samples, data and information which will be made available to an unprecedented degree. IPY 2007““2008 aims to leave a legacy of enhanced observational systems, facilities and infrastructure. The observational networks to be established during IPY include integrated ocean observing systems in both the Arctic and Southern Oceans, coordinated acquisition of satellite data products from multiple space agencies and observational systems for astronomy, sun““earth physics, atmospheric chemistry, meteorology, ecosystems, permafrost, glaciers and geophysics. Many observing systems within IPY will be developed within the framework of existing international global observing systems

Prevalence of Plasmodium falciparum infection among pregnant women at first antenatal visit in post-Ebola Monrovia, Liberia

Background: Disruption of malaria control strategies during the West African 2014–2016 Ebola epidemic led to an increase in malaria-attributable mortality. However, recent data on malaria infection in vulnerable groups, such as pregnant women, are lacking in this post-Ebola scenario. This cross-sectional study aimed to assess the prevalence of Plasmodium falciparum infection and of molecular markers of drug resistance among pregnant women attending antenatal care in Monrovia, capital of Liberia. Methods: From October 2016 to June 2017, all pregnant women attending their frst antenatal care visit at the Saint Joseph’s Catholic Hospital, Monrovia, were invited to participate in the study. In addition to their routine antenatal care tests, capillary blood spotted onto flter papers were collected from all consenting participants to determine presence of P. falciparum by real-time quantitative PCR. Molecular markers of anti-malarial drug resistance were assessed through Sanger sequencing and quantitative PCR in specimens positive for P. falciparum analysis. Results: Of the 195 women participants, 24 (12.3%) were P. falciparum-positive by qPCR. Infected women tended to be more commonly primigravidae and younger than uninfected ones. Parasite densities were higher in primigravidae. Fever was more frequently detected among the infected women. No statistically signifcant association between P. falciparum infection and haemoglobin levels or insecticide-treated net use was found. While high prevalence of genetic polymorphisms associated with chloroquine and amodiaquine resistance were detected, no molecular markers of artemisinin resistance were observed. Conclusion: Plasmodium falciparum infections are expected to occur in at least one in every eight women attending frst ANC at private clinics in Monrovia and outside the peak of the rainy season. Young primigravidae are at increased risk of P. falciparum infection. Molecular analyses did not provide evidence of resistance to artemisinins among the P. falciparum isolates tested. Further epidemiological studies involving pregnant women are necessary to describe the risk of malaria in this highly susceptible group outside Monrovia, as well as to closely monitor the emergence of resist‑ ance to anti-malarials, as recommended by the Liberian National Malaria Control Programme

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

Behaviour and orcadian rhythm of the fish bathygobius soporator Valenciennes (Gobiidae) under the influence of environmental salinity and temperature

The behavioural patterns and their cireadian rhythms may be adaptive to the peculiar environmental conditions of subtropical brackish waters where Ba-thygobius soporator Valenciennes, 1837 live. Adult fish were caught at the southern Brazilian coast from mangrove rivers and rocky shores in a bay, where temperature and water salinity vary during the day and through the year. Observation on the behaviour of the animals was undertaken in salinity 8.5ppt, 17.0ppt, 25.5ppt and 34.0ppt, each one in temperatures of 18ºC and 28ºC. Temperature and salinity affect the frequency and intensity of some of the behavioural events, more than its pattern or rhythm. Swimming is rare, decreasing along the day and with temperature increase, being even lower at low salinity; aggressiveness is the highest in the morning being not affected by temperature, but by salinity, being higher the higher it is; territory defence decreases along the day and is lower at high temperature and extreme salinities; fish hide more at high temperature and with the decrease of salinity, but this is not rhythmical; a higher proportion of fish rest in vertical position when salinity and temperature are high, increasing slightly at the beginning of the afternoon; respiratory frequency increases with temperature, salinity and in the afternoon; the colour of the fish is mainly light with spots in all hours of the day and in all temperatures and different levels of salinity, but with a tendency of the presence of some dark fish during the morning and some light ones in the afternoon, showing a higher variability of colours at low temperature and extreme salinities. Besides temperature, salinity and light, feeding seems to be one of the determinant factors for the performance of the typical behaviour of B. soporator

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

The effect of temperature increase on the behavior of Antarctic fish

Along the gradual increase in the water temperature from 0℃ to 10℃ at a rate of 1℃/h, respiratory and behavioral alterations were observed in the Antarctic Notothenidae fish Trematomus bernacchii, Notothenia neglecta and Notothenia rossii marmorata. The main reaction of N. neglecta was a gradual increase in the respiratory frequency; N. rossii marmorata and T. bernacchii presented both a manifestive temperature of 4.5℃, N. rossii marmorata being the most affected according to the behavior observed

The effect of temperature on the muscle oxygen levels in Antarctic fish

Direct measurements of the available oxygen in the muscle were carried out by the implanting of polarographic sensors in living Notothenidae (Pisces, Teleostei). Curves for normal oxygen levels corresponding to air-saturated water at 0° and under the eifect of gradual increasing of the temperature were obtained

コトナル エンブン ニ タイスル ナンキョクサン ノトセニアカ ギョルイ Notothenia (Gobionotothen) gibberifronsトTrematomus newnesi ノ サイジョウ ヒソウ サイボウ ノ ケイタイ ヘンカ オヨビ イッパン ケイタイ ト コウドウジョウ ノ ヘンカ

南極沿岸の浅海域では, 海水の凍結, 融解に伴う塩分濃度の変化が顕著である。ここに生息する魚類が, いかに塩分の濃度の変化に適応しているかを調べるために, 南極半島, キングジョージ島, アドミラルティ湾産のNotothenia (Gobionotothen) gibberifronsとTrematomus newnesiを異なる塩分環境下で実験的に飼育した。鰓上皮層にある塩分細胞, 粘液分泌細胞の形態の変化を観察したところ顕著な変化が認められた。合わせて, 体色などの外部形態の変化, 行動の変化についての観察も行った。In coastal Antarctic regions, melting and freezing affect water salinity. The aim of this study was to compare morphological changes of branchial epithelial cells in two species of Antarctic fishes, Notothenia (Gobionotothen) gibberifrons and Trematomus newnesi, and to detect behavioral consequences. They occur in Admiralty Bay (King George Island) during the summer, in a mean salinity of 32‰. Tests were conducted in the salinity range between 26‰ to 38‰ in experiments. Chloride cells in T. newnesi are roundish or elongated, with a small apex, at 32‰, thin with a large apex at low salinity, and roundish with small intrusions at the surface at 38‰. Chloride cells are elongated in N. (G.) gibberifrons at normal and low salinity, and increase in number, size and activity at 38‰ with large intrusions at the apical surface. In both species, mucous cells increase in volume, number and activity with salinity increase, being less active at low salinity. Epithelial detachment are observed at high salinity in T. newnesi and in low salinity in N. (G.) gibberifrons. Behavioral consequences of branchial cellular changes were observed : linear decrease of respiratory frequency with salinity increase; swimming decrease with salinity changes, except that at 26‰ forced swimming occurs and at 38‰ lethargy is interrupted by brisk jumps; paleness occurs with salinity decrease and darkness with salinity increase. These symptoms seem to be secondary consequences of hypoxia and ionic changes