Infectious Necrotizing Enteritis and Mortality Caused by \u3cem\u3eVibrio carachariae\u3c/em\u3e in Summer Flounder \u3cem\u3eParalichthys dentatus\u3c/em\u3e During Intensive Culture

An epizootic causing mortality among cultured summer flounder Paralichthys dentatus occurred in summer of 1998 at a land-based facility on Narragansett Bay, Rhode Island, USA. The disease, flounder infectious necrotizing enteritis (FINE), was characterized by reddening around the anal area, distended abdomens filled with opaque serosanguineous fluid, enteritis and necrosis of the posterior intestine. In extreme cases of the disease, the posterior intestine was detached from the anus and was observed coming out the vent. The intestine of individuals that recovered from the dsease ended in a blind-sac; the abdomens of these fish were distended, due to food and water inside the intestinal blind-sac. A bacterium was isolated from ascites fluid and kidney of moribund flounder and identified as the causative agent in challenge experiments. The pathogen was identified as Vibno carchariae by morphological and biochemical characteristics and sequence of the 16S rRNA. The LD50 estimate was 5 x 105 colony-forming units injected intraperitoneally into 100 to 200 g summer flounder

No-Boundary Thinking in Bioinformatics Research

Currently there are definitions from many agencies and research societies defining bioinformatics as deriving knowledge from computational analysis of large volumes of biological and biomedical data. Should this be the bioinformatics research focus? We will discuss this issue in this review article. We would like to promote the idea of supporting human-infrastructure (HI) with no-boundary thinking (NT) in bioinformatics (HINT)

Monitoring activities of teenagers to comprehend their habits: study protocol for a mixed-methods cohort study

Abstract: Background: Efforts to increase physical activity in youth need to consider which activities are most likely to be sustained over time in order to promote lifelong participation in physical activity. The Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study is a prospective cohort study that uses quantitative and qualitative methods to develop new knowledge on the sustainability of specific physical activities. Methods/design: Eight hundred and forty-three grade 5 and 6 students recruited from 17 elementary schools in New Brunswick, Canada, are followed-up three times per year. At each survey cycle, participants complete self-report questionnaires in their classroom under the supervision of trained data collectors. A sub-sample of 24 physically active students is interviewed annually using a semi-structured interview protocol. Parents (or guardians) complete telephone administered questionnaires every two years, and a health and wellness school audit is completed for each school. Discussion: MATCH will provide a description of the patterns of participation in specific physical activities in youth, and enable identification of the determinants of maintenance, decline, and uptake of participation in each activity. These data will inform the development of interventions that take into account which activities are the most likely to be maintained and why activities are maintained or dropped

Effect of triiodothyronine on the growth and survival of larval striped bass (Marone saxatilis)

This study was carried out to test the effect of triiodothyronine (T3) on the growth and survival of larval striped bass (Morone saxatilis). Growth and survival of striped bass held in 5 ppt seawater and treated with various doses of T3 were measured beginning at 5 and 16 days after hatching. Body content of T3 was measured by radioimmunoassay. T3 dissolved in the 5 ppt seawater was taken up by larval striped bass in a dose-dependent manner, and affected the growth and survival of the fish. At 5 days after hatching, T3 at 100 ng ml-1 and 50 ng ml-1 retarded the growth of larval striped bass and caused a lower survival rate than T3 at 25 ng ml-1 or the control treatment. At 16 days after hatching, T3 at 100 ng ml-1 retarded the growth of larval fish and caused a higher mortality. T3 at 10 ng ml-1 and 1 ng ml-1 did not show any effect on either survival or growth. Body content of T3 returns to control levels within days following end of treatment. The results indicate that exogenous T3 can be detrimental to the growth and survival of larval striped bass

Investigations into the causes of early larval mortality in cultured summer flounder (Paralichthys dentatus L.)

Experiments were conducted to investigate larval mortality in cultured summer flounder during the first 2 weeks after hatch. The influence of feeding success, parentage, addition of algae, water quality, and the microbial community on mortality during this period were investigated. Larvae were raised in 2-1 bowls at initial densities of 50 or 75/l with mild aeration, 12 L:12 D photoperiod, and regular 50% water changes. In all experiments, mortalities were recorded and removed daily. In the first two experiments, daily samples of larvae were taken to assess feeding success and to relate that to survival. The second experiment investigated the effects of both feeding success and the addition of algae to larval culture bowls on larval survival. The third experiment investigated the effects of water quality and bacterial load on survival during the experimental period. The first two experiments indicated that failure to establish feeding is probably not the cause of catastrophic mortality of the larvae, although a statistical relationship existed between feeding incidence and survival in two of six cases. High variability (34 ± 38%, n = 82) in survival was seen in the first two experiments (both within and between parental crosses) suggesting that catastrophic mortalities were due to rearing conditions in addition to gamete quality. The addition of algae to larval cultures increased survival from 13 ± 24% (n = 33) in the absence of algae during the first experiment to 46 ± 39% (n = 49) with the addition of algae during the second experiment. The final experiment indicated that larval mortality was not linked to the measured microbial or water quality conditions. The relationship between the percentage of floating eggs at time of fertilization and survival at 10 days after hatch was not significant

Effect of triiodothyronine on stomach formation and pigmentation in larval striped bass (Morone saxatilis)

We previously reported that ambient T3 was taken up by larval striped bass (Morone saxatilis) in a dose-dependent manner, and, at 100 ppb T3-salt in 5 ppt seawater, ambient T3 retarded the growth of the fish. Here we examined the effects of T3 on the histogenesis of the stomach and on pigmentation of larval striped bass. Striped bass larvae were raised in 0, 1, 10, or 100 ppb T3-Na salt in 5 ppt seawater beginning at 16 days after hatching (dah) and sampled after 1 or 2 weeks of treatment. Between ages 23 dah and 30 dah, the muscular layer of the stomach thickened in all groups, and, at both times, the stomachs of fish treated with the highest dose of T3 had a significantly thicker muscular layer than stomachs of untreated fish. The length of the fundic stomach doubled between sampling times in the control fish; this developmental change was promoted by the lowest dose after 1 week exposure, but after 2 weeks this and the development of the gastric blind-sac were significantly inhibited in fish treated with the medium and high concentrations. The fundic region of the stomach of all fish examined at each sampling time (n = 48) contained gastric glands in which pepsinogen was immunolocalized; however, because of the smaller size of the fundic region and the absence of the gastric blind-sac, many fewer gastric glands were detected in fish treated with the two higher concentrations. Somatic pigmentation increased between 23 dah and 30 dah and was also stimulated by exogenous T3 in a dose-dependent manner within 1 week. After 2 weeks of treatment, only fish exposed to 100 ppb T3-Na salt were more pigmented than the control fish. Although development of pigmentation and the muscular wall of the stomach were accelerated by T3, effects of treatment on differentiation and possibly functioning of the fundic region were more complex and possibly detrimental

Complete Amino Acid Sequences of a Pair of Fish (Tilapia) Prolactins, tPRL\u3csub\u3e177\u3c/sub\u3e and tPRL\u3csub\u3e188\u3c/sub\u3e

The complete amino acid sequences of a pair of tilapia (Oreochromis mossambicus) prolactins (PRLs) were determined. The larger PRL of molecular mass 20,836 Da consists of 188 amino acid residues. The smaller PRL of molecular mass 19,584 Da is 11 residues shorter. On alignment of the two sequences, the 19.6-kDa PRL (tPRL177) has two conspicuous deletions on the NH2- terminal side of the disulfide bond which connects the first and second cysteine residues. The degree of similarity between the two PRL sequences is unexpectedly low (130 identical residues, 69%) compared with that between the variants of other teleostean PRLs. Circular dichroism spectra and hydropathy profiles suggest structural similarity of the two PRLs. The sequence of the 20.8-kDa PRL (tPRL188) has 69% identity with that of salmon PRL. The sequence of tPRL177 is 56% identical with that of salmon PRL. Each tilapia PRL is equally similar to mammalian PRLs (about 30% identical residues). Regions highly conserved among teleostean and mammalian PRLs were identified on the COOH-terminal side of the disulfide bond connecting the first and second cysteine residues

Intestinal uptake of lipovitellin from brine shrimp (Artemia franciscana) by larval inland silversides (Menidia beryllina) and striped bass (Morone saxatilis)

Intestinal uptake of lipovitellin (LV) from brine shrimp (Artemia franciscana) in larval inland silversides (Menidida beryllina) and striped bass (Morone saxatilis) was described using immunocytochemistry. Polyclonal antisera were raised against two subunits of LV (LV68 and LV190). When tested by immunocytochemistry, anti-LV68 showed cross-reactivity with some of the pancreatic cells especially in inland silversides. Therefore anti-LV190 was used to localize immunoreactive LV. Inland silversides at 14 days after hatching were fed Artemia nauplii and then sampled 4, 8, 12 hr after feeding. Similar experiments were carried out by using striped bass at 5 days and 15 days of age. They were sampled at 2, 4, 8, and 12 hr after feeding. Anterior enterocytes showed no evidence of uptake; however, the brush border of the cells of inland silversides reacted with the antiserum. Posterior enterocytes took up the LV and/or, possibly, their immunoreactive breakdown products. The pattern of uptake included accumulation in supranuclear vacuoles and digestion in supranuclear vacuoles, as suggested by the decay of the immunoreactivity over time. Thus, the posterior intestine of these larval fishes is the site of uptake and digestion of LV, an important nutritive component in the food of many larval fishes; this supports earlier findings using non-nutritive marker proteins

Metamorphosis of summer flounder (Paralichthys dentatus): Thyroid status and the timing of gastric gland formation

We investigated the timing of stomach formation in metamorphosing summer flounder (Paralichthys dentatus) and the role of thyroid status in gastric gland appearance and pepsinogen production. In the first experiment, untreated summer flounder from successive developmental stages were analyzed using histochemistry and immunocytochemistry. During prometamorphosis, the epithelial folds in the region of the incipient stomach increased. Early in metamorphosis, a few gastric glands appeared, but pepsinogen was not identified until mid-metamorphosis. The stomach of late-metamorphic summer flounder had well-developed gastric glands comparable to those in the juvenile. In the second and third experiments, premetamorphic summer flounder were maintained in seawater containing the vehicle DMSO (control) or seawater containing either 100 ppb L-thyroxine sodium salt (T4) or 30 ppm thiourea (TU, an inhibitor of T4 synthesis). Thyroxine induced metamorphosis within 1 week in the second experiment and within 3 days in the third experiment, whereas TU delayed or inhibited the transition into metamorphosis. The timing of gastric gland differentiation and pepsinogen production was accelerated by 2 weeks in T4-treated larvae and delayed or, in the case of pepsinogen production, inhibited in TU-treated larvae. Thus, T4 stimulates the formation of gastric glands and is necessary for the appearance of pepsinogen in metamorphosing summer flounder. In the third experiment, T4 induced gastric glands within 3 days and in larvae that had not entered metamorphosis, showing that differentiation of gastric glands could be dissociated from metamorphosis. This artificially induced heterochrony has potential application in aquaculture