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Adenosine 5'-triphosphate flux through the north inlet marsh system.

The distribution, fluctuation, and short-term transport of total microbial biomass (measured as adenosine 5'-triphosphate [ATP]) was investigated in a large salt marsh creek. Hourly samples were collected synoptically for 25 h from 10 boats positioned across the 320-m width of the creek. Samples were collected from three depths ranging from 0.2 to 8.0 m. Hourly data obtained from each station were graphed, plotting depth against ATP. Subsequently, interpolated ATP values were generated for every one-tenth depth from the surface to the bottom with the use of an 11-point proportional divider. A total of 2,750 values were generated, and a mean value of 0.865 mg of ATP per m was determined. Maximum levels of ATP were found at high tide and minimal values were found at low tide. The distribution of ATP concentrations was found to be complex, with no suggestion of vertical stratification; however, horizontal divisions were apparent. ATP values corrected for direction of flow or velocity indicated two ebb-directed channels; however, when considered in total, there was a net import of ATP through the interface. The total import of ATP for this 25-h sampling period was calculated to be 3.58 kg, corresponding to a net transport of 39.8 mg of ATP per s through the cross section. Results suggest that detailed characterization of a creek transect in terms of ATP or any similar parameter requires the simultaneous measurements of both the concentration of the parameter in question and the velocity at the time and point from which the sample was taken.

Journal Article↗

Distribution of indicator bacteria and Vibrio parahaemolyticus in sewage-polluted intertidal sediments.

The impact of a sewage point source on the bacterial densities in an intertidal mud flat in Boston Harbor, Mass., was investigated. The area, Savin Hill Cove, acts as a receiving basin for a combined storm and sewage outlet (CSO). Preliminary examination of sediments and overlying water at high tide demonstrated that fecal coliforms were present in sediments at abundances 2 to 4 orders of magnitude higher than in the overlying water column. The following bacterial counts were determined from sediments along a sampling transect extending 460 m from the CSO: total bacteria by epifluorescent microscopy, heterotrophic bacteria by plate counts on nutrient-rich and nutrient-poor media, fecal coliforms and enterococci by membrane filtration, and Vibrio parahaemolyticus by a most-probable-number technique with a resuscitation step. Median sediment grain size, average tidal exposure, carbon/nitrogen ratio, and total organic carbon were also measured. All bacterial indices, except for V. parahaemolyticus, declined significantly with distance from the outfall. Multiple regression analysis indicated that tidal exposure (low tides) may affect densities of total bacteria. Fecal coliforms and enterococci were still present in appreciable numbers in sediments as far as 460 m away from the CSO. In contrast, V. parahaemolyticus densities did not correlate with the other bacterial counts nor with any of the environmental parameters examined. These results indicate that intertidal sediments which adjoin point sources of pollution are severely contaminated and should be considered as potentially hazardous reservoirs of sewage-borne diseases.

Enterobacteriaceae↗

Persistence and biodegradation of spilled residual fuel oil on an estuarine beach.

The enrichment of hydrocarbon-degrading bacteria and the persistence of petroleum hydrocarbons on an estuarine beach after a spill of residual fuel oil on 11 April 1973 in Upper Narragansett Bay, R.I. was investigated. A rapid enrichment occurred during days 4 to 16 after the oil spill and a significant population of hydrocarbon-degrading bacteria was maintained in the beach sand for at least a year. The concentration of petroleum hydrocarbons in the mid-tide area declined rapidly during the bacterial enrichment period, remained fairly constant throughout the summer, and then declined to a low concentration after 1 year. An increased concentration of branched and cyclic aliphatic hydrocarbons in the low-tide sediment 128 days after the spill suggested a migration of hydrocarbons during the summer. Hydrocarbon biodegradation was apparent during the winter months at a rate of less than 1 mug of hydrocarbon per g of dry sediment per day.

Alkanes↗

Resistance to adefovir dipivoxil in lamivudine resistant chronic hepatitis B patients treated with adefovir dipivoxil.

BACKGROUND: Adefovir dipivoxil (ADV) is a potent nucleotide analogue against both the wild-type and lamivudine (LMV) resistant hepatitis B virus (HBV). The cumulative incidence of ADV resistant mutations in the nucleoside/-tide treatment naive chronic hepatitis B patient (CHB) at weeks 48, 96, and 144 was 0, 0.8-3%, and approximately 5.9%, respectively. AIMS: The aim of this study was to characterise the genotypic and phenotypic mutation profiles to ADV in 67 LMV resistant CHB patients who were treated with ADV. METHODS: Serum HBV DNA was quantified by real time polymerase chain reaction. The ADV mutant was detected using matrix assisted laser desorption/ionisation time of flight mass spectrometry based genotyping assays, termed restriction fragment mass polymorphism (RFMP). RESULTS: RFMP analysis revealed that a total of 11 amino acid substitutions developed in the rt domain of the HBV polymerase in nine patients. The cumulative incidence of genotypic ADV resistance at months 12 and 24 was 6.4% and 25.4%, respectively. The rtA181V, rtN236T, and rtA181T mutations were detected in five, four, and two of the 67 patients at treatment months 12-17, 3-19, and 7-20, respectively. Serial quantification of serum HBV DNA revealed that two patients with the rtA181V mutation, with or without the rtN236T mutation, and one patient with the rtA181T mutation displayed HBV DNA rebound. CONCLUSION: Emergence of the ADV mutation in LMV resistant patients who are treated with ADV appeared to present earlier and more frequently than was reported in previous studies on nucleoside/-tide treatment naive patients.

Adenine↗

Altered environment and risk of malaria outbreak in South Andaman, Andaman & Nicobar Islands, India affected by tsunami disaster.

BACKGROUND: Pools of salt water and puddles created by giant waves from the sea due to the tsunami that occurred on 26th December 2004 would facilitate increased breeding of brackish water malaria vector, Anopheles sundaicus. Land uplifts in North Andaman and subsidence in South Andaman have been reported and subsidence may lead to environmental disturbances and vector proliferation. This warrants a situation analysis and vector surveillance in the tsunami hit areas endemic for malaria transmitted by brackish water mosquito, An. sundaicus to predict the risk of outbreak. METHODS: An extensive survey was carried out in the tsunami-affected areas in Andaman district of the Andaman and Nicobar Islands, India to assess the extent of breeding of malaria vectors in the habitats created by seawater flooding. Types of habitats in relation to source of seawater inundation and frequency were identified. The salinity of the water samples and the mosquito species present in the larval samples collected from these habitats were recorded. The malaria situation in the area was also analysed. RESULTS: South Andaman, covering Port Blair and Ferrargunj sub districts, is still under the recurring phenomenon of seawater intrusion either directly from the sea or through a network of creeks. Both daily cycles of high tides and periodical spring tides continue to cause flooding. Low-lying paddy fields and fallow land, with a salinity ranging from 3,000 to 42,505 ppm, were found to support profuse breeding of An. sundaicus, the local malaria vector, and Anopheles subpictus, a vector implicated elsewhere. This area is endemic for both vivax and falciparum malaria. Malaria slide positivity rate has started increasing during post-tsunami period, which can be considered as an indication of risk of malaria outbreak. CONCLUSION: Paddy fields and fallow land with freshwater, hitherto not considered as potential sites for An. sundaicus, are now major breeding sites due to saline water. Consequently, there is a risk of vector abundance with enhanced malaria transmission potential, due to the vastness of these tsunami-created breeding grounds and likelihood of them becoming permanent due to continued flooding in view of land subsidence. The close proximity of the houses and paucity of cattle may lead to a higher degree of man/vector contact causing a threat of malaria outbreak in this densely populated area. Measures to prevent the possible outbreak of malaria in this tsunami-affected area are discussed.

Animals↗

Identification and evaluation of glutamine-related gene characteristics based on multi-omics to predict the prognosis of patients with colorectal cancer.

BACKGROUND: Colorectal cancer (CRC), a prevalent malignancy of the gastrointestinal tract, ranks among the leading causes of cancer-related morbidity and mortality. Its clinical course is marked by high fatality and poor prognosis. Elucidating the mechanisms underlying CRC initiation and recurrence is therefore critical for identifying novel therapeutic targets. METHODS: This study incorporated two datasets, TCGA-CRC and GSE17537. A total of 84 glutamine metabolism-related genes (GMRGs) were identified, and differential expression analysis was conducted using the TCGA-CRC dataset. Weighted Gene Co-expression Network Analysis (WGCNA) was applied to determine gene modules most strongly associated with GMRG scores. Single-cell RNA sequencing (scRNA-seq) was utilized to characterize key cellular clusters and to identify differentially expressed genes (DEGs) between high and low glutamine metabolism (GM) groups. Overlapping GMRGs were visualized using the ggVennDiagram package in R. A CRC risk prediction model was developed through Cox proportional hazards and LASSO regression analyses, with performance evaluated by ROC curves. Cell type enrichment across 64 immune and stromal populations was assessed via xCell, and intergroup differences were tested using the Wilcoxon rank-sum test. TIDE scores were used to estimate immunotherapy responsiveness, while oncoPredict facilitated drug sensitivity profiling. PCOLCE2 expression in CRC was validated by RT-qPCR and Western blotting. Its functional role was examined through CCK-8 assays, invasion and migration tests, flow cytometry, and glutamate quantification. RESULTS: ScRNA-seq analysis identified two key cell populations and 437 DEGs associated with GM status. WGCNA pinpointed the MEgreen module as most significantly correlated with GMRG scores, encompassing 1075 genes. Integration of DEGs, module genes, and GM-related DEGs yielded 60 candidate genes for downstream analysis. A GMRG-based prognostic model comprising six genes (SRPX, CXCL1, GPX3, PCOLCE2, CLU, SEMA3E) demonstrated strong predictive performance. Prognostic gene expression correlated with immune and stromal infiltration patterns, as indicated by Spearman correlation analysis. The high-risk group exhibited diminished predicted response to immunotherapy (TIDE scores). Drug sensitivity analysis identified four compounds—Dasatinib-51, WH-4-023-56, TWS-119-366, and LDN-193189-478—with elevated efficacy in high-risk CRC cases. PCOLCE2 expression was significantly reduced in CRC tissues. Functional assays revealed that PCOLCE2 knockdown did not substantially affect cell proliferation but significantly impaired invasion and migration in CRC cells, increased apoptosis, and suppressed both glutamine uptake and glutamate production—highlighting its oncogenic role. CONCLUSION: Six GMRGs—SRPX, CXCL1, GPX3, PCOLCE2, CLU, and SEMA3E—were identified as key components of a robust prognostic model for CRC. These findings offer valuable insights into CRC pathogenesis and potential therapeutic strategies. Notably, this study provides the first evidence implicating PCOLCE2 as a tumor-promoting factor in CRC.

Glutamine↗

Air breathing of aquatic burrow-dwelling eel goby, Odontamblyopus lacepedii (Gobiidae: Amblyopinae).

Odontamblyopus lacepedii is an eel goby that inhabits both coastal waters and intertidal zones in East Asia, including Japan. The fish excavates burrows in mudflats but, unlike the sympatric amphibious mudskippers, it does not emerge but stays in the burrows filled with hypoxic water during low tide. Endoscopic observations of the field burrows demonstrated that the fish breathed air in the burrow opening; air breathing commenced 1.3 h following burrow emersion, when water P(O2) was approximately 2.8 kPa, with an air-breathing frequency (f(AB)) of 7.3+/-2.9 breaths h(-1) (mean +/- s.d., N=5). Laboratory experiments revealed that the fish is a facultative air breather. It never breathed air in normoxic water (P(O2)=20.7 kPa) but started bimodal respiration when water P(O2) was reduced to 1.0-3.1 kPa. The fish held air inside the mouth and probably used the gills as gas-exchange surfaces since no rich vascularization occurred in the mouth linings. As is known for other air-breathing fishes, f(AB) increased with decreasing water P(O2). Both buccal gas volume (V(B)) and inspired volume (V(I)) were significantly correlated with body mass (M(b)). At a given M(b), V(I) was nearly always equal to V(B), implying almost complete buccal gas renewal in every breathing cycle. A temporal reduction in expired volume (V(E)) was probably due to a low aerial gas exchange ratio (CO2) elimination/O2 uptake). Air breathing appears to have evolved in O. lacepedii as an adaptation to aquatic hypoxia in the burrows. The acquisition of the novel respiratory capacity enables this species to stay in the burrows during low tide and extends the resident time in the mudflat, thereby increasing its chances of tapping the rich resources of the area.

Air↗

Adaptation to temperature stress and aerial exposure in congeneric species of intertidal porcelain crabs (genus Petrolisthes): correlation of physiology, biochemistry and morphology with vertical distribution

We examined physiological and biochemical responses to temperature and aerial exposure in two species of intertidal porcelain crabs (genus Petrolisthes) that inhabit discrete vertical zones. On the shores of the Northeastern Pacific, P. cinctipes (Randall) occurs under rocks and in mussel beds in the mid to high intertidal zone and P. eriomerus (Stimpson) occurs under rocks in the low intertidal zone and subtidally to 80 m. Because of their different vertical distributions, these two species experience very different levels of abiotic stress. Individuals of P. cinctipes can be emersed during every low tide, but P. eriomerus is only emersed during the lowest spring tides and on most days is not emersed at all. Temperatures measured underneath rocks in the mid intertidal zone were as high as 31 °C, 15 °C higher than maximal temperatures measured under rocks in the low intertidal zone. In air, at 25 °C, large specimens of P. cinctipes were able to maintain a higher respiration rate than similarly sized P. eriomerus. No interspecific differences in the respiratory response to emersion were seen in small specimens. Examination of the response of heart rate to temperature revealed that P. cinctipes has a 5 °C higher Arrhenius break temperature (ABT, the temperature at which there is a discontinuity in the slope of an Arrhenius plot) than its congener (31.5 °C versus 26.6 °C). The heart rate of P. cinctipes recovered fully after exposure to cold (1.5 °C), but the heart rate of P. eriomerus did not recover after exposure to 2 °C or cooler. The ABT of heart rate in P. cinctipes was very close to maximal microhabitat temperatures; thus, individuals of this species may be living at or near their thermal tolerance limits. P. cinctipes were able to maintain aerobic metabolism during emersion, whereas P. eriomerus shifted to anaerobic metabolism. A pronounced accumulation of whole-body lactate was found in specimens of P. eriomerus incubated in air at 25 °C over a 5 h period, but not in P. cinctipes similarly treated. P. cinctipes possesses a membranous structure on the ventral merus of each walking leg, but this structure is not found in P. eriomerus. To test the function of the leg membrane, we measured the aerial respiration rates and the lactate accumulation of P. cinctipes with their leg membranes obscured. These individuals had significantly lower aerial respiration rates at 30 °C than control crabs. Crabs with leg membranes obscured also accumulated a considerable amount of lactate during a 5 h period of emersion at 28 °C, but control crabs showed no accumulation under the same conditions. These data suggest that the leg membrane functions as a respiratory structure. The results of this study illustrate that a suite of morphological, physiological and biochemical features allows P. cinctipes to live higher in the intertidal region than P. eriomerus.

Journal Article↗

Effects of feeding on arterial blood gases in the American alligator Alligator mississippiensis.

Reptiles habitually ingest large meals at infrequent intervals, leading to changes in acid-base status as the net secretion of acid to the stomach causes a metabolic alkalosis (the alkaline tide). In chronically cannulated and undisturbed amphibians and reptiles, the pH changes in arterial blood are, nevertheless, reduced by a concomitant respiratory acidosis (increased P(CO2) caused by a relative hypoventilation). Alligators (Alligator mississippiensis) have been reported to exhibit exceptionally large increases in plasma [HCO3(-)] following feeding, but these studies were based on blood samples obtained by cardiac puncture, so stress and disturbance may have affected the blood gas levels. Furthermore, crocodilian haemoglobin is characterised by a unique binding of HCO3(-) that act to reduce blood oxygen-affinity, and it has been proposed that this feature safeguards oxygen offloading by counteracting pH effects on blood oxygen-affinity. Therefore, to study acid-base regulation and the interaction between the alkaline tide and oxygen transport in more detail, we describe the arterial blood gas composition of chronically cannulated and undisturbed alligators before and after voluntary feeding (meal size 7.5+/-1% of body mass). Digestion was associated with an approximately fourfold increase in metabolic rate (from 0.63+/-0.04 to 2.32+/-0.24 ml O(2) min(-1)kg(-1)) and was accompanied by a small increase in the respiratory gas exchange ratio. The arterial P(O2) of fasting alligators was 60.3+/-6.8 mmHg (1 mmHg = 0.133 kPa) and reached a maximum of 81.3+/-2.7 mmHg at 96 h following feeding; there was only a small increase in lactate levels, so the increased metabolic rate seems to be entirely aerobic. Plasma [HCO3(-)] increased from 24.4+/-1.1 to 36.9+/-1.7 mmol l(-1) (at 24 h), but since arterial P(CO2) increased from 29.0+/-1.1 to 36.8+/-1.3 mmHg, arterial pH remained virtually unaffected (changing from 7.51+/-0.01 to 7.58+/-0.01 at 24 h). The changes in plasma [HCO3(-)] were mirrored by equimolar reductions in plasma [Cl(-)]. The in vitro blood oxygen-affinity was reduced during the post-prandial period, whereas the estimated in vivo blood oxygen-affinity remained virtually constant. This supports the view that the specific HCO3(-) effect prevents an increased blood oxygen-affinity during digestion in alligators.

Alligators and Crocodiles↗

Specific toxic effect of dinoflagellate Heterocapsa circularisquama on the rotifer Brachionus plicatilis.

Heterocapsa circularisquama (Dinophyceae), a noxious red tide dinoflagellate, is known to have a specifically lethal effect on shellfish, especially bivalves such as pearl oyster (Pinctada fucata), but no detrimental effects of this alga on fishes have not been observed so far. In this study, we found that H. circularisquama was toxic to a microzooplankton, a rotifer (Brachionus plicatilis) in a cell concentration-dependent manner, while the cultured supernatant or ultrasonic ruptured H. circularisquama had no significant toxic effect on the rotifer. Since no such toxic effects on the rotifer were observed in Chattonella marina, Heterosigma akashiwo, or Cochlodinium polykrikoides, other species of harmful red tide plankton, H. circularisquama may have a strictly specific toxic mechanism against the rotifer as well as bivalves.

Animals↗

Inhalation toxicity of brevetoxin 3 in rats exposed for twenty-two days.

Brevetoxins are potent neurotoxins produced by the marine dinoflagellate Karenia brevis. Exposure to brevetoxins may occur during a K. brevis red tide when the compounds become aerosolized by wind and surf. This study assessed possible adverse health effects associated with inhalation exposure to brevetoxin 3, one of the major brevetoxins produced by K. brevis and present in aerosols collected along beaches affected by red tide. Male F344 rats were exposed to brevetoxin 3 at 0, 37, and 237 microg/m3 by nose-only inhalation 2 hr/day, 5 days/week for up to 22 exposure days. Estimated deposited brevetoxin 3 doses were 0.9 and 5.8 microg/kg/day for the low- and high-dose groups, respectively. Body weights of the high-dose group were significantly below control values. There were no clinical signs of toxicity. Terminal body weights of both low- and high-dose-group rats were significantly below control values. Minimal alveolar macrophage hyperplasia was observed in three of six and six of six of the low- and high-dose groups, respectively. No histopathologic lesions were observed in the nose, brain, liver, or bone marrow of any group. Reticulocyte numbers in whole blood were significantly increased in the high-dose group, and mean corpuscular volume showed a significant decreasing trend with increasing exposure concentration. Humoral-mediated immunity was suppressed in brevetoxin-exposed rats as indicated by significant reduction in splenic plaque-forming cells in both low- and high-dose-group rats compared with controls. Results indicate that the immune system is the primary target for toxicity in rats after repeated inhalation exposure to relatively high concentrations of brevetoxins.

Aerosols↗

Natural and derivative brevetoxins: historical background, multiplicity, and effects.

Symptoms consistent with inhalation toxicity have long been associated with Florida red tides, and various causal agents have been proposed. Research since 1981 has centered on a group of naturally occurring trans-fused cyclic polyether compounds called brevetoxins that are produced by a marine dinoflagellate known as Karenia brevis. Numerous individual brevetoxins have been identified from cultures as well as from natural bloom events. A spectrum of brevetoxin derivatives produced by chemical modification of the natural toxins has been prepared to examine the effects of functional group modification on physiologic activity. Certain structural features of natural and synthetic derivatives of brevetoxin appear to ascribe specific physiologic consequences to each toxin. Differential physiologic effects have been documented with many of the natural toxins and derivatives, reinforcing the hypothesis that metabolism or modification of toxin structures modulates both the specific toxicity (lethality on a per milligram basis) and potentially the molecular mechanism(s) of action. A series of naturally occurring fused-ring polyether compounds with fewer rings than brevetoxin, known as brevenals, exhibit antagonistic properties and counteract the effects of the brevetoxins in neuronal and pulmonary model systems. Taken together, the inhalation toxicity of Florida red tides would appear to depend on the amount of each toxin present, as well as on the spectrum of molecular activities elicited by each toxin. Toxicity in a bloom is diminished by the amount brevenal present.

Animals↗

A study of the fish community structure in a tidal creek.

The fish assemblage in a mangrove tidal creek was studied in monthly collections between August 1998 and July 1999 in the quadrature low tide and high tide, using a fyke net of 30 m x 1.5 m and meshes of 8 and 10 mm. Simultaneously with the biological collections, temperature, salinity, pH, water transparency, and current speed data were obtained. The collections resulted in the capture of 36,873 fish representing 22 families and 52 species. Immature individuals abounded (63.8%), and among the adult specimens there was a larger number of females. The species Anchoa parva, Harengula clupeola, Genidens genidens, and Bairdiella ronchus, contributed to 84.9% of the total capture of fish, however the contribution in mass was of 55.2%, indicating a predominance of small individuals. A smaller number of fish and species seem to occupy the area in the period between August and December, in comparison to the period between February and July, when the larger aggregations appear, mainly of the species Anchoa parva, Harengula clupeola, Opisthonema oglinum, Genidens genidens, Diapterus rhombeus, and Bairdiella ronchus. The environmental factors, pH, water transparency, and rainfall seem to have an influence in the structure of the observed biological patterns.

Animals↗

A cuproptosis-related lncRNAs-based risk signature for predicting prognosis and immune status in glioma.

BACKGROUND: Glioma is one of the most prevalent primary malignant brain tumors, characterized by poor prognosis and limited treatment options. Recent studies have identified cuproptosis, a novel copper-dependent form of regulated cell death, as a critical mechanism involved in tumor progression. However, the role of cuproptosis-related long non-coding RNAs (lncRNAs) in glioma remains not fully clarified. This study aimed to develop and validate a prognostic model based on cuproptosis-associated lncRNAs to predict patient outcomes and guide individualizing therapeutic strategies. METHODS: Transcriptomic profiles and clinical data were obtained from The Cancer Genome Atlas (TCGA), The Genotype-Tissue Expression (GTEx), and the Chinese Glioma Genome Atlas (CGGA) databases. Cuproptosis -related prognostic lncRNAs were filtered via univariate and multivariate Cox and Least absolute shrinkage and selection operator (LASSO) regression analyses, which were selected to establish a prognostic model for glioma. Samples were divided into high- and low-risk groups, and the predictive performance of the prognostic model was evaluated based on receiver operating characteristic (ROC) curves, Kaplan-Meier (K-M) survival curves, and a nomogram. In addition, immune cell infiltration, tumor mutational burden (TMB), immunophenoscore (IPS), Tumor Immune Dysfunction and Exclusion (TIDE) and drug sensitivity were analyzed. Expression levels of selected lncRNAs and proteins were validated using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and Western blotting. RESULTS: An 11-lncRNA signature associated with cuproptosis was established, and the risk score derived from this model was identified as an independent prognostic factor for glioma. The model exhibited excellent predictive ability, with area under the curve (AUC) values of 0.880, 0.913, and 0.866 for 1-, 3-, and 5-year survival, respectively. Higher TMB, immune checkpoint expression, and IPS were observed in the high-risk group and no significant difference was observed in TIDE between risk groups. Drug sensitivity analysis identified TPCA-1, KIN001-135, and ispinesib mesylate as potential therapeutic agents. Expression validation in glioma cells further supported the biological relevance of the selected lncRNAs. CONCLUSIONS: This cuproptosis-related lncRNA-based signature demonstrates strong prognostic value and may serve as a promising tool for glioma risk stratification and personalized treatment selection.

Glioma↗

Clinical and epidemiological features of neurotoxic shellfish poisoning in North Carolina.

BACKGROUND: In October 1987, a red tide due to P. brevis affected the North Carolina coast for the first time. The purpose of our study was to describe the clinical and epidemiological features of neurotoxic shellfish poisoning (NSP), an illness caused by eating shellfish contaminated with the neurotoxins of P. brevis. METHODS: Active surveillance was established for cases of NSP. A descriptive study of the NSP cases was then completed. RESULTS: Forty-eight persons, who had eaten oysters at 20 meals, met the case definition. A variety of gastrointestinal tract and neurological symptoms were reported. The illnesses were generally mild and of short duration, and there were no deaths. Forty-one (85 percent) affected persons lived in five communities located within a 70-kilometer area along the coast. Cases occurred from October 27 to December 9; 27 (56 percent) of the cases occurred before the first closure of affected shellfish waters on November 2. There was a significant increase in the illness attack rate with an increase in the number of oysters eaten. CONCLUSIONS: Routine monitoring of coastal waters for P. brevis is needed to facilitate earlier recognition of red tides, closure of affected areas, and education of the public before substantial exposure to contaminated shellfish occurs.

Adolescent↗

A circa-decadal change in the gastropod fauna on a tidal flat in an island mangrove estuary.

An investigation on gastropod fauna was carried out on a tidal flat in the Nagura Estuary on Ishigaki Island, the Ryukyu Islands in 1989 and 1998 using similar methods. 470-480 quadrats covering ca. 1900 m2 were surveyed during low tides from February to April in each year. Of the total 19 species recorded, the ranges of eight species had varied significantly between the two surveys, with six species expanding their range and two species contracting their range. Percentage in abundance of muddy-bottom species and tropical (<29 degrees N) species increased significantly between the two years. Topography of the flat also changed: the mouth of the river was narrowed and the elevated sections of the tidal flat expanded. During the period from 1984 to 1998, the farmland development around the study site caused influxes of soil into the estuary and the sea-water temperature was rising. These results suggest that the topographical changes due to soil influx and the rising temperature affected the gastropod assemblage at the study site, by increasing the abundance of muddy-bottom species and tropical species. The methodology used in this study, i.e. surface observation at low tides, includes more than 95% of the gastropod fauna, demonstrating the usefulness of surface counts for the study of soft-bottom fauna.

Animals↗

Reproductive swarming of sympatric nereidid polychaetes in an estuary of the Omuta-gawa river in Kyushu, Japan, with special reference to simultaneous swarming of two Hediste species.

Habitat differences and spatial and temporal separation in reproductive swarming among sympatric nereidid polychaetes were examined in an estuary of the Omuta-gawa River, Kyushu, Japan by annual periodical sampling from December 2003 to January 2005. Benthic adults of Tylorrhynchus osawai and Hediste diadroma occupied mainly the upper reaches of the estuary, whereas those of H. japonica usually inhabited the middle reaches, though their distributions overlapped. Reproductive swarming of mature adults occurred in the estuary just after high tide at night during spring tides in four nereidids: H. japonica (in the middle and lower reaches from late December to late February), H. diadroma (throughout the whole estuary from middle December to late April), T. osawai (in the middle reaches and another estuary from late October to late December), and Nectoneanthes oxypoda sensu Imajima, 1972 (in the lower reaches in late April and early May). This result shows that temporal separation of reproductive swarming may act as a reproductive isolation mechanism among these nereidids, except for H. japonica and H. diadroma. Simultaneous swarming and mass-spawning of the two Hediste species were commonly observed in the middle and lower reaches from late December to early February, suggesting the absence of a pre-spawning barrier to reproductive isolation between them. We found no difference in spawning behavior between H. japonica and H. diadroma. Males of both species seemed to participate in swarming earlier than females.

Animals↗

Patterns and processes of larval emergence in an estuarine parasite system.

Trematode parasites in intertidal estuaries experience constantly varying conditions, with the presence or absence of water potentially limiting larval transport between hosts. Given the short life spans (< or =24 h) of cercariae, emergence timing should be optimized to enhance the probability of successful transmission. In the present study, field measurements and laboratory experiments identified processes that regulate the emergence of cercariae from their first intermediate snail hosts in an intertidal marsh. Larvae emerged over species-specific temperature ranges, exclusively during daylight hours, and only when snails were submerged. The three factors operate over different temporal scales: temperature monthly, light diurnally (24-h period), and water depth tidally (12-h period). Each stimulus creates a necessary condition for the next, forming a hierarchy of environmental cues. Emergence as the tide floods would favor transport within the estuary, and light may trigger direct (downward or upward) swimming toward host habitats. Abbreviated dispersal would retain asexually reproduced cercariae within the marsh, and local mixing would diversify the gene pool of larvae encysting on subsequent hosts. In contrast to the timing of cercarial release, emergence duration was under endogenous control. Duration of emergence decreased from sunrise to sunset, perhaps in response to the diminishing lighted interval as the day progresses. Circadian rhythms that control cercarial emergence of freshwater species (including schistosomes) are often set by the activity patterns of subsequent hosts. In this estuary, however, the synchronizing agent is the tides. Together, exogenous and endogenous factors control emergence of trematode cercariae, mitigating the vagaries of an intertidal environment.

Animals↗