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The parapineal is present in many teleost families, while it is absent in several others. To find out why the parapineal is absent at adult stages in the latter families, the development of the epithalamus was examined in the medaka fish (Oryzias latipes). For this purpose, a green fluorescent protein-transgenic medaka line, in which the pineal complex (pineal and parapineal) is visible fluorescently, was used. We found that a distinct parapineal was present in the roof plate at early developmental stages. Subsequently, however, the parapineal and the associated roof plate began to be incorporated into the habenula between embryonic stages 28 and 29. Between embryonic stages 29 and 30, the entire parapineal was incorporated into the habenula. That is, the parapineal became a small caudomedial region (termed the ‘parapineal domain') within the left habenula in the majority of embryos, resulting in the left-sided asymmetry of the epithalamus. Thereby the left habenula became larger and more complex than its right counterpart. In the minority of embryos, the parapineal was incorporated into the right habenula or into the habenulae on both sides. In the majority of embryos, the parapineal domain projected a fiber bundle to a subnucleus (termed the ‘rostromedial subnucleus') in the left habenula. The rostromedial subnucleus sent axons, through the left fasciculus retroflexus, to the rostral region of the left half of the interpeduncular nucleus. We further found that the ratio of the left-sided phenotype was temperature dependent and decreased in embryos raised at a high temperature. The present study is the first demonstration that the supposed lack of a distinct parapineal in adult teleost fishes is due to ontogenetic incorporation into the habenula.

A scanning electron microscope (SEM) was used to investigate the morphology and distribution of setae and hairs on the larval mid leg femur, tibia, and third tarsomere in representatives of six genera of Perlodidae and Perlidae. On the ventral surfaces of these leg segments we observed previously described clothing hairs, spine-like setae, and pinnate setae. We describe for the first time a new type of seta that we refer to as candle-like seta. Distinct differences in the distribution of hairs and setae are exhibited between the two families. Perlidae have hairy legs and on the femur the percentage of setae as compared to that of the clothing hairs is very high. Perlodidae are less hairy and on the femur the percentage of setae as compared to clothing hairs is much lower. The distribution of setae and hairs is similar among genera in the Perlidae, but not between genera of the Perlodidae. Pinnate setae are observed only in Neoperla geniculata. We discuss the types of setae and their distribution on the la...

To maximize their growth, grazers should shift their behavior to balance the cues from predators and periphyton in the field. As a stream grazer seeks periphyton that are heterogeneously distributed, a shift in its behavior on the basis of the intensity of microalgal cues would be beneficial as it would allow the grazer to feed on more periphyton. Using a caddisfly grazer, Glossosoma larvae, we conducted a laboratory channel experiment with upstream experimental plates having four levels of periphyton abundance (control, low, medium, and high), and we recorded the movement behavior of the larvae. As periphyton abundance increased, both larval crawling time and the total crawling distance to the periphyton patch significantly decreased and the directness of the crawling path significantly increased. That is, larvae crawled in various directions as they approached a relatively low-abundance periphyton patch, whereas they crawled straight to the high-abundance periphyton patch in a short time. The behavior change was likely due to the detection of some microalgal cue, which should intensify with an increase in upstream periphyton abundance. Chemical and visual cues play important roles in the interactions between organisms (Lima 1998; Burks and Lodge 2002). Many studies have established that these cues are involved in predator–prey interactions. By recognizing predator cues, prey can change their life histories, morphologies, activity, and habitat use to avoid predation (McIntosh et al. 1999; Miyasaka et al. 2003; Turner and Montgomery 2003). Likewise, predators can be attracted to food patches by recognizing cues from animal prey

静岡産業大学情報学部では、授業で利用する資料としてデジタルコンテンツを学生に配付したり、課題をデジタルデータとして提出させたりしている教員がいる。しかし、その配付や提出の方法は各教員により異なるため、統一した教材サーバを確立し効率の良い授業展開が行われることが望まれている。当初は商用の外部サーバシステムの利用を考えてみたが、商用であるため有料であり、利用する教員のみならず、学生も課題提出などを行うためには有料アカウント登録をする必要があったり、本学部のコンピュータ演習室に設置されているMacintosh(3室120台)上では利用することができなかったりしたために断念することになった。一方、多くの大学が有料の教育支援システムを導入して、デジタル教材の提供、テスト問題の出題、提出、採点、記録や出席管理等を総合的に行っており私立大学情報教育協会の調査によると、平成20年度には7割の私立大学がこのシステムの導入をする計画を持っている。しかし、本学においては予算的な面などからも高額な有料ソフトを導入することは難しい。そこで、国内の大学でも利用され、事例報告等も多くされているMoodle(ムードル:Modular Object-Oriented Dynamic Learning Environment)を利用することを考えた。Moodleは海外で開発され、オープンソースであるフリーソフトウェアのLMS (Learning Management System)であり、このソフトを本学部の複雑なカリキュラム体系に適合するようにカスタマイズすることで、多くの教員がストレスを感じること無く利用できるシステムを構築することができると思われる。教員がコンピュータに関して初心者であっても、比較的簡単に学生に対して教材の提供を行うことができるシステムを構築できるか検証することにした。

We examined the larval population densities and biomass of a caddisfl y grazer, Micrasema quadriloba, and the abundance and community structures of periphyton at a segment scale (7.4 km with four study sites), along a second- to fourth-order Japanese mountain stream through- out the grazer's life cycle. In the uppermost riffl e of the study segment (site 1), periphyton abundance was kept at low levels when the larvae occurred. The larval distribution spread downstream as larvae developed from fi rst instars in May to fi fth instars in January. We performed multiple regression analyses to test the effects of environmental variables and larval biomass on periphyton abundance in both the riffl e of site 1 and the study segment; the results revealed that the larval biomass was signifi cantly negatively correlated with periphyton abundance similarly in both the riffl e and the study segment. In addition, both the correla- tion and community analyses showed that the larval biomass was signifi cantly negatively correlated to the rela- tive abundance of large and/or fi lamentous microalgae, which appeared in the uppermost layer of the periphyton mat, and that larval biomass was signifi cantly positively correlated to the relative abundance of small diatoms, which strongly adhered to the substrate. Thus, the present study implied that the grazing of M. quadriloba larvae would regulate the abundance of periphyton in a riffl e and also regulate the abundance and community structure of periphyton at the segment scale with the expansion of their longitudinal distribution.

Summary Several herbivorous insects are known to benefit from feeding in groups; however, little is known about (1) the resource conditions under which herbivorous insects perform group feeding and (2) the optimum population size to get any benefits by group feeding, for example, in terms of growth performance. To test the hypotheses that the benefits from group feeding change with resource level and population size, we performed field investigations and an enclosure experiment using the grazer caddisfly larva Micrasema quadriloba . The field investigations revealed aggregated distributions of larvae (indicator of aggregation, I δ =4.1±1.55, aggregated density: 12.7±5.3 individuals per 3.1×3.1 cm 2 (mean±1 SD)) when periphyton was abundant on stream cobbles and random distributions ( I δ =1.0±0.11) when periphyton was scarce. In the enclosure experiment, the relative growth rate (RGR) of the larvae at each population size showed different tendencies at high and low periphyton abundance levels; RGR with abundant periphyton had a convex curve with a peak at intermediate population size, whereas RGR with scarce periphyton decreased linearly with increasing population size. The benefits from group feeding thus changed with resource level; larvae obtained high growth performance by group feeding behavior only when the resource was sufficiently abundant. The present study revealed not only that the optimum group size of larvae increased their growth performance, but also that this optimum group size occurred frequently in the field. We also discuss the mechanisms and benefits of group feeding by case-bearing caddisfly grazers.

The present study investigated whether room temperature (T(a)) cycles around dusk and dawn could influence the circadian rhythm of rectal temperature (T(core)), urinary 6-hydroxymelatonin sulfate during nocturnal sleep, and subjective assessments of sleep in humans. Six female and two male students served as participants. Two different T(a) conditions, cyclic and constant, were established. Two kinds of room temperature were provided to subjects: cyclic T(a) (gradual decrease from 27 degrees C to 24 degrees C between 1800 and 2200 h and gradual increase from 24 degrees C to 27 degrees C between 0300 and 0700 h) and constant T(a) (27 degrees C over 24 h). At cyclic T(a), the circadian nadir of T(core) rhythm was significantly advanced, while T(core) was significantly lower from 2300 to 0200 h and significantly higher from 0600 to 1000 h. The nocturnal concentration of 6-hydroxymelatonin sulfate in the urine during sleep was significantly higher during cyclic T(a). Waking sensation just after rising was significantly better with cyclic T(a). (Skin temperatures in the extremities-T(a)) were significantly higher with cyclic T(a) especially during the evening and night. Our results suggest that gradual change of room temperature in the evening and early morning is important in terms of sleep promotion and fresh awakening. It seems probable that mankind has been evolved to have deeper sleep under the influence of cyclic T(a) around dusk and dawn.

Effects of 17beta-estradiol and p-nonylphenol were examined in the immune and endocrine organs of Japanese quail embryos. The test compounds were injected into the yolk of embryonated eggs. Injection of estrogen resulted in (1) disappearance of lymphoid cells and flattened development of plicae in the bursa of Fabricius, (2) decreased area of thyroid follicles and height of simple cuboidal epithelial cells in the thyroid, (3) increased follicular appearance of the thymus, and (4) development of an ovotestis in male embryos. Injection of nonylphenol did not induce flattened plicae in the bursa of Fabricius or development of an ovotestis in male embryos, but it increased the disappearance of lymphoid cells from the lymphoid follicles in the bursa, decreased the height of simple cuboidal epithelial cells surrounding the thyroid follicle, and increased the follicle-like structure in the thymus in male embryos. These results suggest that nonylphenol has estrogenic effects, but these are low compared to those of estrogen itself.

Egg period was compared among several temperature conditions (11°C, 16°C, 20°C, 23°C) in Sweltsa sp., Stavsolus japonicus, and Isoperla aizuana (Plecoptera). The shortest mean egg incubation period was 27.8 days at 20°C in Sweltsa sp., 118.1 days at 16°C in Stavsolus japonicus, and 162.0 days at 20°C in Isoperla aizuana on average. Egg hatching rate was also the highest at the water temperature that provided the shortest egg incubation period. Based on laboratory data, eggs of Sweltsa sp. were considered to be deposited in May and hatched in June in the field. Thus, they must have spent the summer as nymphs in the field. Eggs of Stavsolus japonicus and Isoperla aizuana were considered to be deposited in April to May and hatched in September to October in the field. Visible eyes of Stavsolus japonicus and Isoperla aizuana appeared in August. It is likely that the long egg period of Stavsolus japonicus and Isoperla aizuana reflects that these two species spend the summer as dormant eggs in the field.

This study assesses the effects of ambient light conditions, under a thermoneutral environment, on selected immunological parameters of 7 healthy young women (aged 19 to 22 yrs). Subjects entered the bioclimatic chamber at 11: 00 h, controlled at 26 degrees C and 60% relative humidity, a "neutral climate". They lead a well-regulated life in the climatic chamber (pre-condition) while exposed to dim (200 lux) or, on the next day, bright (5000 lux) light between 06 : 00 to 12 : 00 h. Just before the end of each period of light exposure, a blood sample was taken for later immunological assay of white blood cell count (WBC), phagocytosis, interferon-gamma (IFN-gamma), interleukin-4 (IL-4), CD69 T cells (CD69), CD4+CD25+ T cells (CD4+CD25+), and transforming growth factor-beta 1 (TGF-beta1). The results, when compared with the pre-condition, were as follows: 1) CD69 and IFN-gamma increased during normal conditions without thermal stress under dim light; 2) WBC increased and IL-4 decreased under bright light; 3) as shown by the highly significant decrease of TGF-beta1, the immune system was activated under bright light; 4) phagocytosis tended to increase under bright light exposure; 5) CD69 and IFN-gamma were significantly higher, and CD4+CD25+ tended to decrease under bright light; 6) phagocytosis tended to be lower and TGF-beta1 significantly higher under dim light, indicating a decline of immune system function. Taken together, this preliminary single time-point sampling study infers that some parameters are activated (CD69) while others are attenuated (phagocytosis, TGF-beta1) according to the environmental light intensity, dim vs. bright, in women adhering to a standardized routine in the absence of thermal stress. These findings are discussed in terms of inhibition of the sympathetic and excitation of the parasympathetic nervous system under the influence of life-style regularity and daytime bright light exposure.

This study investigates the relationship between circadian typology, i.e., morningness-eveningness (M-E) preference, and the occurrence and severity of premenstrual mental and physical symptoms among 154 young Japanese female university students (range, 18 to 31 yrs; mean+/-S.D., 20.69+/-3.69 yrs) and 417 junior high school students (range, 12 to 15 yrs; mean+/-S.D., 14.29+/-0.67 yrs) living in an urban or suburban area of Kochi prefecture. Female university students experienced melancholy mood more frequently than did males, and the female university students who frequently became melancholy were more evening-typed than those who did not experience melancholy. Female university students who experienced frequent fluctuations in mood and/or menstrual pain were more evening-typed than those who were not so affected. M-E preference of junior high school students was not correlated with stability of mood or frequency of menstrual pain. In urban areas, however junior high school students who had very stable menstrual cycles were significantly more morning-typed than those whose menstrual cycles were not stable. In suburban areas, the bedtimes of female junior high students who had stable menstrual cycles were significantly earlier than those whose menstrual cycle duration was not stable. A physiological relationship between the circadian system, M-E, and attributes of the menstrual cycle seems to be present in adolescent female Japanese junior high school students.

We investigated the correlation between torpor frequency and capacity for non-shivering thermogenesis (NST) in Siberian hamsters (Phodopus sungorus) during 25 weeks of acclimation to cold and short days. We hypothesized that torpor use is conditioned on the development of brown adipose tissue (BAT) capacity for NST. We found that (1) the degree of noradrenaline (NA)-induced hyperthermia was positively correlated with torpor frequency and its length and depth, and (2) the maximum response to NA occurred at the time of day when hamsters naturally arouse from torpor. The present study quantifies the correlation between torpor frequency and NST capacity and we suggest that a welldeveloped NST capacity is a prerequisite for the occurrence of torpor. r 2004 Elsevier Ltd. All rights reserved.

We investigated the photoperiodic response of serotonin- and galanin (GA)- immunoreactive (ir) cells in the paraventricular organ (PVO) and infundibular nucleus (IF) of the Japanese quail and the interaction of these cells with gonadotropin-releasing hormone (GnRH)-ir neurons in the hypothalamus. Serotonin-ir cells were located in series from the PVO to the IF, and were connected with each other. The number of serotonin-ir cells differed significantly between light and dark phases on the short days (SD), but did not differ between light and dark phases on long days (LD). GA-ir cells were also found in the PVO and IF. The number of GA-ir cells under SD conditions was significantly greater than under LD conditions but did not change diurnally. Both serotonin-ir and GA-ir fibers ran along the GnRH-ir cells in the nucleus commissurae pallii. Serotonin-ir and GA-ir fibers were connected with the GnRH-ir fibers in the external layer of the median eminence (ME). We confirmed that GA-ir fibers were closely associated with serotonin-ir neurons in the PVO and IF. GA-ir neurons have at least 2 routes of regulating GnRH neurons directly, and indirectly via the serotonin-ir cells in the PVO and IF.

Circadian rhythms of amphibians and reptiles in the field and under semi-natural conditions and the underlying mechanisms, including the ways of entrainment to environmental cues and the oscillators driving the rhythms, have been reviewed. Studies on the behavioral rhythms in the field are meager in both amphibians and reptiles. In anuran amphibians, Xenopus adults showed more robust nocturnal locomotor activity than did tadpoles. This indicates the ecological significance of the differences in activity pattern shown by amphibians at different life stages, because differences between adults and young in the same environment may serve to isolate partially the young from the adults' cannibalism. In reptiles, free-running rhythms are more robust and continue for a longer time compared to amphibians. In both amphibians and reptiles, multi-photoreceptors are involved in photo-entrainment of circadian rhythms. The eyes, pineal complex and deep brain comprise a multi-oscillator system as well as a multi-photorec...

Daily variations in plasma melatonin levels in the rainbow trout Oncorhynchus mykiss were studied under various light and temperature conditions. Plasma melatonin levels were higher at mid-dark than those at mid-light under light-dark (LD) cycles. An acute exposure to darkness (2 hr) during the light phase significantly elevated the plasma melatonin to the level that is comparable with those at mid-dark, while an acute exposure to a light pulse (2 hr) during the dark phase significantly suppressed melatonin to the level that is comparable with those at mid-light. Plasma melatonin kept constantly high and low levels under constant darkness and constant light, respectively. No circadian rhythm was seen under both conditions. When the fish were subjected to simulative seasonal conditions (simulative (S)-spring: under LD 13.1:10.9 at 13 degrees C; S-summer: under LD 14.3:9.7 at 16.5 degrees C; S-autumn: under LD 11.3:12.7 at 13 degrees C; S-winter: under LD 10.1:13.9 at 9 degrees C), melatonin levels during the dark phase were significantly higher than those during the light phase irrespective of simulative seasons. The peak melatonin level in each simulative season significantly correlated with temperature but not with the length of the dark phase employed. In addition, the peak melatonin level in S-autumn was significantly higher than those in S-spring although water temperature was the same under these conditions. These results indicate that the melatonin rhythm in the trout plasma is not regulated by an endogenous circadian clock but by combination of photoperiod and water temperature.

The relation between emergence date and the factors concerned in reproduction were studied in the stoneflies Isoperla aizuana (Perlodidae) and Sweltsa sp. (Chloroperlidae) in the laboratory. Individuals emerging earlier had larger adult size and greater adult longevity. Fecundity was also related to emergence date, adult size, and adult longevity. Furthermore, individuals emerging earlier had more days until first effective mating and tended to mate more effectively than later-emerging individuals. The maturity of the reproductive tissue may differ with emergence date. While most of the later-emerging individuals had a lower rate of effective mating, longer-lived and larger size adults mated more effectively in females of Sweltsa sp. The differences in mating character might affect the effectiveness of mating.

1年次で情報リテラシ、2年次でプログラミングの基礎教育を受けた学生が、その後の3学次の情報処理関連科目でどのような成績をとるかを調べた。成績の推移の調査分析にはデータマイニング手法を用いた。すなわち、情報処理関連科目のテスト結果をランク別の学生数の分布で捉え、科目別ランク間の学生の推移数や推移率を算出し、それに基づき相関ルールを抽出し、ルールの分類によってルールの意味を分析する。抽出された幾つかの相関ルールを要約すると、(1) 1、2年でAランクを取れない学生は3年でAランクを取れないこと、(2)大学入学前予備知識のある(職業課程卒)学生が2年でAとCの2つのランクに分かれることである。したがって、学年が上がるにつれてAランクの学生が減る。情報処理技術者(SE)として社会で活躍するには4科目ともAランクであることが望まれる。このような問題を解決するには、科目間での教育の協力方法を改善する必要がある。なお、著者らが担当する科目は情報処理関連科目の一部であるから、全ての科目の成績を反映した相関ルールが得られていると言えない。しかし、授業の進め方などで改善のヒントが他にも多く指摘されたことで、筆者らが提案するデータマイニング手法は、他の科目においても教育方法や講義内容の改善の自己評価手法として役立つように思われる。, This paper reports how many students, who have studied basics of computer literacy at the first grade and programming at the second grade, can master well the advanced computer algorithms and system designs at the third grade or higher. As the means to analyze the student transitions between subject-rank sets, the data mining featured by the following processes has been employed. The first process is to extract association rules to show the main trends of transitions between subject-rank sets from the test data. The second is to categorize the association rules by ranks. The last is to logically analyze the rules by semantics. By summarizing the data mining results, we found the following rules. The first rule shows that the students who could not get A rank at the first and second grades cannot get A rank at the third grade. The second rule shows that the students coming from the business oriented high school keeps the good performance at the first and second grades, but are classified into two groups of ranks A and C at the third grade. As a result, the students of rank A decrease as the grade raises. To solve this problem, we noticed that the collaboration between the subjects must be improved. Since many useful suggestions for better education could be pointed by analyzing the association rules, the authors found that the above mentioned data mining techniques should be used as self-evaluation tools for the other education improvement by the other teachers.

It is well characterized that melanophores in the tail fin of Xenopus laevis tadpoles are directly photosensitive. In order to better understand the mechanism underlying this direct photosensitivity, we performed a retinal analysis of the tail fins and eyes of Xenopus tadpoles at stages 51-56 using high performance liquid chromatography (HPLC). Following the extraction of retinoids by the formaldehyde method, a fraction containing retinal and/or 3,4-didehydroretinal isomers from the first HPLC analysis were collected. These isomers were then reduced by sodium borohydride to convert retinal and/or 3,4-didehydroretinal isomers into the corresponding retinol isomers to prepare for a second HPLC analysis. Peaks of 11-cis and all-trans 3,4-didehydroretinol were detected in the eyes and tail fins containing melanophores, but they were not detected in the tail fins without melanophores. The amounts of 11-cis and all-trans 3,4-didehydroretinol were 27.5 and 5.7 fmol/fin, respectively, and the total quantity of 3,4-didehydroretinal was calculated at approximately 5 x 10(6) molecules/melanophore. These results strongly suggest the presence of 11-cis and all-trans 3,4-didehydroretinal in melanophores of the tadpole tail fin, which probably function as the chromophore of photoreceptive molecules.

Extraretinal photoreceptor cells have been found in the pineal complex and deep brain of a variety of non-mammalian vertebrates. Light signals received by these photoreceptor cells seem to be a potent regulator of diverse physiological responses. Here, the pineal complex and deep brain of the Japanese grass lizard, Takydromus tachydromoides, were immunohistochemically analyzed to localize the photoreceptive molecule (opsin) and the light signal-transducing G-protein (transducin). In addition to the pineal organ and parietal eye constituting the pineal complex, we unexpectedly found a parapineal organ, which is located just below the parietal eye and is morphologically similar to the pineal organ. Both organs had photoreceptor-like cells with outer segments immunostained by anti-rhodopsin and anti-pinopsin antibodies. Neither opsin- nor transducin-like immunoreactivities were detected in the parietal eye with all the antibodies tested in this study, although its morphology resembles that of the la...

Photoperiodism and circadian rhythms have been studied intensively in birds because Aves are typical seasonal breeders and diurnal animals. Light is the most important environmental factor involved in entrainment of circadian rhythms and photoperiodism. The eyes and the extraocular photoreceptors, such as the pineal organ and hypothalamus, are reported to have an important function not only for photoreception but also for circadian organization in nonmammalian vertebrates, including birds. In this report, we review the roles of the eyes, pineal organ, and deep brain as the components of the multiphotoreceptor and multioscillator system in avian circadian organization. Microsc. Res. Tech. 53:43–47, 2001. © 2001 Wiley-Liss, Inc.

We investigated the daily rhythm of the response to noradrenaline injections in Djungarian hamsters (Phodopus sungorus sungorus) at neutral ambient temperature, under long photoperiod (L:D 12:12) and after four weeks of acclimation to cold (10°C) and short photoperiod (L:D 8:16). Animals were injected with noradrenaline (0.6 mg/kg) every four hours. Body temperature and gross motor activity were measured with MiniMitter transmitters implanted into abdominal cavity. Additionally, we measured body weight and food intake prior to, and after acclimation. After four weeks of acclimation, the experiment was performed under LD cycle and then repeated during one-day of constant light (LL) and constant darkness (DD). In animals acclimated to L:D 12:12 and ambient temperature of 25°C, noradrenaline injections caused short-lasting increase in body temperature followed by marked decrease. There was no significant difference in the magnitude of the reaction between light and dark phase of the day. After acclimation to cold and L:D 8:16, under LD conditions, we recorded significant differences between the responses to the noradrenaline injections during light and dark phase of the day. Post-injection increase was higher during the day than during the night while following noradrenaline-induced hypothermia was much more pronounced in darkness. In experiments performed after acclimation to cold and short photoperiod but during one day of LL and DD regimes, these differences were attenuated. Data presented here indicate that in cold acclimated hamsters, the response to exogenous noradrenaline depends on the time of injection and it exhibits clear daily rhythm. The rhythmicity is altered under LL and DD regimes. It seems that post-injection increase in body temperature elicits following hypothermia. This hypothermia might be of a great ecological importance. Reasonable lowering of body temperature would be a protective mechanism, allowing for energy charge restoration.

The pineal complex, deep brain, and skin have been known to function as extraretinal photoreceptors in non-mammalian vertebrates. To see the diversity of localization of extraretinal photoreceptors in lower vertebrates having different habitats, we analyzed the opsin-like immunoreactivities in anuran amphibians, Xenopus laevis, Rana catesbeiana, Rana nigromaculata, and Bufo japonicus. An antiserum (toad Rh-AS) was raised against rhodopsin purified from the retinas of Japanese toad, B. japonicus. In the retina of all the anurans examined, the outer segments of rods were immunopositive to toad Rh-AS. The outer segments of most pinealocytes were immunopositive in R. catesbeiana, R. nigromaculata, and B. japonicus. The outer segments of photoreceptor-like cells within the frontal organ of R. nigromaculata were immunostained. Interestingly, toad Rh-AS immunostained many secretory cells of mucous glands in the head skin of B. japonicus, implying the presence of a novel photoreceptive molecule. Within the hypothalamus, toad Rh-AS immunostained many cells in the magnocellular preoptic nucleus of R. catesbeiana and B. japonicus. Toad Rh-AS also labeled cerebrospinal fluid (CSF)-contacting cells in the anterior preoptic nucleus of R. nigromaculata and those adjacent to the lateral ventricle within the septum of R. catesbeiana. Thus the distribution patterns of the rhodopsin-like immunoreactivities among the anurans were highly diverged, and there was no relationship between the distribution patterns and their habitats. J. Exp. Zool. 286:136-142, 2000.

Locomotor activity rhythms of the Japanese newt, Cynops pyrrhogaster, were recorded under a semi-natural condition using phototransistor systems. The daily activity rhythm showed a seasonal change: the locomotor activity was mainly diurnal (active during the daytime) from spring to early summer; mainly nocturnal (active during the night-time) from summer to autumn; and showed either a diurnal or nocturnal pattern, depending on the ambient temperature, in winter. To analyze the daily activity in detail, we observed the behavior of a group of newts (three males, three females) throughout 24 h. Four types of behavior (respiration, feeding, mating, and resting on the land) were observed. Each behavior had daily rhythms and showed a seasonal change. The behavior on land showed mainly a nocturnal or bimodal pattern (activity rhythms with two peaks) throughout the year and was more frequently observed in summer. Mating behavior also showed a seasonal change: high activity in spring, with peaks in the early morning and evening, but no activity in summer. Except in winter, feeding and respiratory behavior showed no seasonal changes in either activity period or frequency. Coupling between behavior and the clock seems to be weak in the Japanese newt because of indistinct daily rhythms and frequent phase changes of locomotor activity in water. Physical factors such as humidity and temperature seem to affect strongly the daily activity of the newts.

Nonmammalian vertebrates have been known to have photoreceptors in their pineal complex and deep brain as well as the retina. The extraretinal photoreceptors are believed to be essential for seasonal reproduction and regulation of circadian physiology. In this review, we discuss the relation between extraretinal photoreceptors and circadian systems in some species of nonmammalian vertebrates in terms of the pineal as the photoreceptor and oscillator for circadian rhythms, the hypothalamus as a photoreceptor and the extraretinal photoreceptors as the multi-oscillator system for circadian behavioral rhythms. Although immunohistochemical results suggest the existence of rod- and cone-type photoreceptors in the pineal, photoreception in the pineal is not always necessary for circadian systems in nonmammalian vertebrates. Circadian systems are involved in avian photoperiodic gonadal responses, and these responses are induced via deep brain photoreceptors. In some animals, deep brain photoreceptors are stained by antisera against photoreceptor proteins (rhodopsin, iodopsin and transducins). The relationship between the oscillators and photoreceptors is different among species. Physiological significance of this diversity is discussed from evolutional and developmental points of view.

In the retina of the medaka four kinds of retinal cone photoreceptor cells are arranged in a simple, repeating organizational pattern known as a square mosaic. We found that the distribution of cones in the retina could be easily detected by autofluorescence-emission from the photoreceptor cells without any staining. In tangential sections of the retina, cones were located at a specific position in a crystalline lattice as follows: Double cone pairs display a zigzagging appearance, oriented roughly 90-120 degrees to one another, and single cones were in the center of the square consisting of four double cone pairs. In order to determine the continuity of this regular arrangement on the spherical surface, the distribution of this cone mosaic pattern was examined in central, dorsal, ventral, nasal and caudal areas of the retina. The regular arrangement of cones was confirmed in the whole retina. Double cones and single cones are in their respective lines and these lines form a lattice-work. As a re...

The mudskipper, Periophthalmus modestus, inhabits the intertidal zone and is active on the surface of mud flat during low tides. We investigated relationships between the behavior and environmental variables during low tides from daily and annual aspects. The observation was done in two distant sites where tidal cycles and population densities are different. The emergence of the mudskipper on the surface of the tidelands was influenced by ambient temperature; low temperature inhibited emergence and locomotor activity of the mudskipper. The mudskipper retreated into the mud as the time went on after emersion of the tideland in order to avoid increase of body temperature and desiccation of the epidermis. Therefore, the emergence of the mudskipper seems to be directly suppressed by drying up of the mud surface. There were no differences in the diel and annual changes in the activity pattern between the populations. The emergence exhibited synodic changes in both areas, and it was correlated not with...

Relation between retinal melatonin and corneal mitotic rhythms in the Japanese quail was investigated in experiments manipulating the ocular physiology by treatments with formoguanamine hydrochloride (FG) and eye-lid suture. In experiment 1, we investigated the effects of FG, which is known to induce photoreceptor degeneration, on retinal melatonin and corneal mitotic rhythms. FG-treatment completely abolished the retinal melatonin rhythms in both LD 12:12 and constant darkness (DD), but the corneal mitotic rhythm was maintained with high mitotic rate in darkness under a LD cycle and subjective night under DD. The result suggests that 1) the photoreceptor cells in the retina are the site for melatonin production and/or for the oscillator which drives the circadian rhythm in retinal melatonin, and 2) melatonin is not involved in generation of the corneal mitotic rhythm. In experiment 2, we investigated the effects of eye-lid suture, which is known to induce eye enlargement and bulgy cornea, on the retinal melatonin and corneal mitotic rhythms. Eye-lid suture abolished the corneal mitotic rhythm in both LD and DD, with a high mitotic rate being maintained throughout 24 hr. But retinal melatonin maintained its rhythm with high levels in darkness under a LD cycle and in subjective night under DD. The result suggests that 1) bulgy cornea in the sutured eye was induced by the increase in mitotic rate in the light period, and 2) disappearance of the corneal mitotic rhythm does not have a relation to retinal melatonin. These results suggest that retinal melatonin is not involved in generation of the corneal mitotic rhythm and that there are two circadian clock systems in the eye.

This study deals with the daily activity rhythm and its change in a loath,Misgurnus anguillicaudatus, by season and age. We set traps in an irrigation creek and ditches around the paddy fields near Nara city every month for 2 years. The fish appeared in spring, declined in early summer, and increased in mid-summer again, and disappeared in late autumn. The number of fish captured at night was greater than that during the daytime in summer. There were some differences in the daily rhythms by sex and age. Nocturnal activities of males and immatures were more prominent than those of females. Younger generation were more nocturnally active than elders in summer. Changes in the daily activity rhythms of the loath are possibly adaptive to unstable environments around paddy fields.

Stream grazers have a major impact on food web structure and the productivity of stream ecosystems; however, studies on the longitudinal (upstream versus downstream) and temporal changes in their drift dynamics and resulting distributions remain limited. Here, we investigated the longitudinal and temporal distributions and drift propensity of a trichopteran grazer, the caddisfly, Micrasema quadriloba , during its life cycle in a Japanese stream. The distribution of larvae significantly shifted downstream during the fifth instar larval stage during late winter; with periphyton abundance (i.e. their food source) showing similar shifts downstream. Therefore, our results show that the drift dispersal the caddisfly occurs in response to decline in available food resources (i.e. food-resource scarcity) and an increase in food requirements by growing individuals. Furthermore, our results show that this observed longitudinal shift in larval distribution varies through their life cycle, because the drift dispersal of fifth instar larvae was greater than that of immature larvae. The correlation between periphyton abundance and drift propensity of fourth instar larvae was not statistically significant, whereas that of fifth instar larvae was significantly negative. In conclusion, we detected an ontogenetic shift in drift propensity, which might explain the longitudinal and temporal distributions of this species.

Morningness-eveningness (M-E) preference and whether it was related to varying mental and physical conditions during the menstrual cycle of female students attending a Japanese junior high school, located in the suburban region in Nangoku city (33.3 N), Kochi prefecture, was studied. Those students who were beyond their first year after menarche were more evening-typed than those who were in their first year of menarche or those who had not yet begun their menstrual function. The M-E preference has no significant correlation with mood, periodical stability of the menstrual cycle or menstrual pain. The bedtime of those students who had an irregular menstrual cycle was significantly later than that of the students who had a stable cycle.

The aim of this study has been to examine whether iodopsin immunoreaction exists in the photoreceptor cells of the retina of the river lamprey, Lampetra japonica, and whether this immunoreaction also appears in the photoreceptors of the pineal complex. The lamprey retina possesses long and short photoreceptor cells that display iodopsin immunoreactivity and rod-opsin immunoreactivity, respectively. In the pineal organ, iodopsin immunoreaction has been observed in the peripheral region and the dorsal wall of the end-vesicle. Immunoreactivity is also found in the atrium and the pineal stalk. The iodopsin-immunoreactive outer segments are smaller than those displaying rod-opsin immunoreactivity. In the parapineal organ, iodopsin immunoreactivity is distributed in both dorsal and ventral portions. Double immunostaining has been employed to investigate whether iodopsin and serotonin immunoreactivities are colocalized in one and the same cell. This approach has revealed that the iodopsin-immunoreactive outer segments belong to serotonin-immunopositive and to serotonin-immunonegative photoreceptor cells. These results demonstrate that rod-type or cone-type visual pigments are contained in both typical and modified pineal photoreceptors.

We investigated localization of visual pigments in the pineal complex of Japanese quail, Japanese grass lizards and bullfrogs immunocytochemically by use of the antiserum against bovine rhodopsin (Rh-As) and monoclonal antibodies against chicken iodopsin (Io-mAb). We also analyzed retinoids, chromophores of visual pigments, by a high performance liquid chromatography (HPLC). The outer segments and cell membranes of some photoreceptor cells in the pineal organ of the Japanese quail exhibited immunoreactivity to Rh-As, but there are also many immunonegative cells. The number of immunoreactive cells among individuals varied. Immunoreactivity to Io-mAb was weak or did not exist. The HPLC analysis revealed peaks of 11-cis and all-trans isomers of retinal in the oxime extracts of the pineal organ of Japanese quail and chickens. In the pineal of Japanese grass lizards, the outer segments of some cells were immunopositive to Io-mAb, but there were no cells immunoreactive to Rh-As. The parietal eye exhibited a well-developed lens and photoreceptor cells, but the outer segments of photoreceptor cells were immunonegative to both Rh-As and Io-mAb. In bullfrogs, three types of cells were identified in both the pineal and frontal organ; (1) immunopositive to Rh-As, (2) immunopositive to Io-mAb and (3) immunonegative to either of the antibodies. In the pineal organ of bullfrogs, 11-cis and all-trans retinal and 11-cis 3-dehydroretinal were detected, and 11-cis and all-trans retinal were also detected in the frontal organ. We detected 11-cis and all-trans retinal in the ventral part of diencephalon including the hypothalamus. Thus, the chromophore is the same between the retinal and pineal visual pigments, but the expression of opsins is different between the retina and pineal complex, which probably reflects the different function of each organ.

Breeding cycles and fecal gonadal steroids were investigated in free-living brown dippers, Cinclus pallasii. The brown dippers were marked with colored leg bands, and their behavior was observed by a field scope. The breeding season was divided into six stages according to the behavior observed; winter territory-defending, nest-building, copulation, incubation, nestling, and fledgling stages. Fecal pellets on the stones in their territories were collected and the levels of immunoreactive estradiol-17 beta (E2) and testosterone (T) in 10 mg feces were measured by radioimmunoassay. Levels of fecal E2 were high only during the copulation stage, which lasted for a few weeks, in all females of the three pairs observed. In contrast, T levels in the feces of males increased in late winter when intensive territory-defending behavior was observed, and remained high until the end of the breeding season. T levels during the nest-building stage and the copulation stage were similar to those during other nesting stages. When the birds breed only once a year, the duration of high levels of T was shorter than that of the pair with the second clutch. T levels in the feces of females showed a similar pattern to E2 levels.

We investigated the effects of castration on the development of lymphoid organs (bursa of Fabricius, thymus, and spleen) in the Japanese quail during 4–8 weeks of age under a long photoperiod (16L:8D) and the effect of testosterone implantation on the involution of the lymphoid organs under long (16L:8D) and short (8L:16D) photoperiods. Under 16L:8D, the bursa of Fabricius and thymus in intact quail grew rapidly and reached a peak at 6 weeks of age and regressed thereafter. In contrast, development of the lymphoid orgas in castrated quail was well correlated with the body growth. Testosterone treatment induced a significant reduction in relative bursal weight to body weight at 6 weeks of age under 16L:8D and 8 weeks of age under 16L:8D and 8L:16D, in relative thymus weight at 6 weeks of age under 16L:8D and 8L:16D, and in relative spleen weight at 6 weeks of age under 8L:16D. Thus, we conclude that gonadal hormones play an important role in the development and involution of lymphoid organs.

Several neurotoxins are known which destroy some specific retinal component or other link in the visual pathway. We have employed such reagents to induce blindness in chicks, in order to explore the role of vision in the development of light-induced avian glaucoma (LIAG) and/or lid-suture myopia (LSM). Chicks made pharmacologically blind with formoguanamine failed to develop LSM. Under LIAG conditions, increased eye weight and global enlargement did not occur, but the characteristic anterior segment changes were seen. Thus LIAG globe enlargement, and LSM axial lengthening, appear to be vision-driven, but anterior segment changes are probably separately controlled. The retinal neurotoxin kainic acid rendered chicks behaviorally blind in the eye into which it was injected intravitrially, but this failed to prevent LIAG changes in either anterior segment or growth of the globe. Chicks reared under LSM conditions, and treated with kainic acid were not different from untreated controls, in that they developed globe enlargement in spite of their pharmacologically-induced blindness. Preliminary trials with quisqualic acid, another retinal neurotoxin, indicate that this agent, like kainic acid, cannot prevent LIAG eye enlargement. Several quis-treated eyes developed phthisis bulbi however, and thus could not be included among those assessed for eye weight and dimensional measurements.