Effects of transfer to sea water on standard and routine metabolic rates in smolting Atlantic salmon at different stages of seawater adaptability

Juvenile Atlantic salmon were transferred to sea water at three different times corresponding to different levels of seawater tolerance, i.e. before (A) and at two times (B and C) during the completion of parr-smolt transformation. Changes in their standard and routine metabolic rates were evaluated by measuring oxygen consumption. The time at which these transfers had been carried out and, consequently, the fish adaptability to sea water affected their post-transfer metabolism. Indeed, transfer A induced a decrease in mean metabolic rate; under standard conditions, this could be ascribed to a lowered protein turnover. The depression in routine oxygen consumption, which occurred at daylight, was interpreted as an adaptative response to a possible limitation in oxygen supply to the tissues. This limitation would result from a decrease both in the gas diffusing capacity of gills and in oxygen affinity of haemoglobin assumed from changes in plasma ions. Transfers B and C increased standard metabolism; this was probably induced by a stimulation of protein turnover. No outstanding change was noticed in routine oxygen consumption of fish after transfer B. On the other hand, the re-occurrence of a circadian rhythm of routine metabolism in sea water after transfer C is interpreted as the disappearance of physiological disturbances following a prolonged stay of fish in fresh water.     

An ecological survey of the heavy metal contamination of the edible clam Paphia sp. on the iron-ore tailings of Tolo Harbour,Hong Kong

Summary Iron-ore tailings have been deposited along the coast of Tolo Harbour from Ma On Shan Iron-ore Mine since its operation in 1906. In order to search for any harmful effects caused by the tailings, the edible clam, Paphia sp. together with sediments and seawater samples were collected from different sites of the iron-ore tailings of Ma On Shan Iron Mine, its nearby seashores and an unaffected site, Cheung Chau. The analysis of metal contents in the tissue and shell of the clams, seawater and sediments was carried out. It was discovered that the clams collected from the tailings had accumulated higher metal contents, e.g. Mn, Fe and Ca while those collected from the nearby seashores were also affected to a less extent.Clams are collected from the seashores within Tolo harbour for consumption by the villagers, but no accident caused by toxic effects of heavy metals has been reported. However, the present investigation further confirmed the potential hazard of the heavy metal contamination within Tolo Harbour reported recently (Wong & Chan, 1976; Wong & Tam, 1977).     

Assessment of Fluoride in Three Selected Polluted Environments along the Egyptian Mediterranean Sea: Effects on Local Populations

Fluoride ion (F^?) is a relevant component of concern due to its potential toxicity for humankind. This study clarifies the status of F^? for human health in three polluted regions along the Egyptian Mediterranean Sea coast, and determining its contents in seawater and different fish tissues (muscle, skin, brain, and bone). Fluoride ion concentrations in different fish tissues had a descending trend of brain > skin > muscle > bone with averages of 26.8 ± 26.0, 24.8 ± 6.5, 12.7 ± 2.3, and 9.0 ± 1.6 μg F^?/g wet wt, respectively. The bioconcentration factor for fluoride ion in different fish tissues was determined and multivariate analyses were conducted. The human health hazard assessment from fish consumption and seawater contact using hazard quotient (HQ) and ingestion and dermal absorption dose of whole body for different ages of females and males as well as the specified body parts (legs, arms, and hands) were calculated. Although the calculated daily intake values for ingestion of fish in the present study were lower than some established tolerable daily intake values, their hazard quotients were within 1 ≥ HQ < 10 and may reflect a possible fluoride adverse effect on human health from the consumption of the gathered fish species.     

Distribution of microaerophilic bacteria through the oxic-anoxic transition zone of lagoon sediments

In marine sediments, where soluble gases diffuse only very slightly, many organisms struggle for molecular oxygen. Microaerophilic bacteria, able to grow at reduced pO₂ between 0.2 and 12%, have an advantage. Distribution of aerobes, microaerophiles and anaerobes was compared with the oxygen gradient in seawater and sediment samples collected in a northern Mediterranean lagoon. In the near bottom seawater and in the 0–10 mm upperlayer of sediment, the microaerophilic counts were less than 1% of aerobe densities. In the 10–15 mm zone, these two groups were equivalent in density (1 × 10⁵ cells ml^–1). As expected, the microaerophiles took advantage of their low oxygen tension requirements in the subsurface sediments, between the well aerated zone (0–5 mm depth) and the low redox potential zone. Then, beyond a depth of 20 mm, the anaerobes prevailed in this sandy clay.     

黑莓汁的理化特性及贮藏期营养成分的变化

对黑莓浓缩汁的理化特性及其营养成分变化进行研究,结果表明：ｐＨ３～４,波长５１１～５１４ｎｍ时,果汁色泽最佳;果汁抗氧化还原能力很弱,但具有很强的光和热的稳定性。０～４℃低温贮藏１年后,６种维生素的损失率都超过５０％;含糖量损失４０７％;ＳＯＤ活性和氨基酸含量分别损失１０％和１２４％;含酸量略有增加     

Genetic differences in physiology, growth hormone levels and migratory behaviour of Atlantic salmon smolts

Out of five strains of Atlantic salmon Salmo salar of 1+ years released upstream of a fyke net in the River Gudenaa in 1996, three, Lagan, Ätran and Corrib, migrated immediately, 50% of the recaptured fish reaching the net in 3–6 days. Burrishoole and Conon fish migrated with a 15–19 day delay. Smolt development in 1997 at the hatchery showed a spring surge in gill Na⁺, K⁺-ATPase activity in all strains which was correlated with increased seawater tolerance. Differences in the timing of gill enzyme development matched the observed migration pattern well. Lagan, Ätran and Corrib strains reached high enzyme activity earlier than the Burrishoole and Conon strains, and strains with delayed enzyme development and migration showed a delayed regression of seawater tolerance compared with the early strains. Inter-strain differences in plasma growth hormone profiles could not be related to the observed patterns of Na⁺, K⁺-ATPase and seawater tolerance development. The study gives evidence of genetic influence on the timing and intensity of smolting and subsequent migration in Atlantic salmon.     

Different <Emphasis Type="Italic">Planctomycetes</Emphasis> diversity patterns in latitudinal surface seawater of the open sea and in sediment

The 16S rRNA gene approach was applied to investigate the diversity of Planctomycetes in latitudinal surface seawater of the Western Pacific Ocean. The results revealed that the Pirellula-Rhodopirellula-Blastopirellula clade dominated the Planctomycetes community at all surface seawater sites while the minority genera Gemmata and Planctomyces were only found at sites H5 and H2 respectively. Although the clone frequency of the PRB clade seemed stable (between 83.3% and 94.1%) for all surface seawater sites, the retrieved Pirellula-Rhodopirellula-Blastopirellula clade presented unexpected diversity. Interestingly, low latitude seawater appeared to have higher diversity than mid-latitudes. integral-LIBSHUFF software analysis revealed significantly different diversity patterns between in latitudinal surface seawater and in the sediment of South China Sea station M2896. Our data suggested that different hydrological and geographic features contributed to the shift of Planctomycetes diversity in marine environments. This is, to our knowledge, the first systematic assessment of Planctomycetes in latitudinal surface seawater of the open sea and the first comparison of diversity pattern between surface seawater and sediments and has broadened our understanding of Planctomycetes diversity in marine environments.     

The cryopreservation of high concentrated PBMC for dendritic cell (DC)-based cancer immunotherapy

Peripheral blood mononuclear cells (PBMC) have been accepted as a unique material for cancer immunotherapy using dendritic cells (DC) or activated lymphocytes that are being developed as an alternative or adjuvant to conventional therapies such as surgery, chemotherapy and radiation treatment. Although successful cryopreservation of large numbers of PBMC is critical for the immunotherapy, subsequent functional study of the effects of PBMC cryopreservation on differentiation into immune cells has not been well defined. In this study, over 1.0 × 10⁸ cells/ml PBMC were cryopreserved as long as 52 weeks using a controlled-rate freezer (CRF) and stored in a vapor phase of liquid nitrogen tank. The effect of PBMC cryopreservation on differentiation into DC was studied by comparing the phenotypic and functional properties of immature DC (iDC) and mature DC (mDC) derived from cryopreserved PBMC to those from fresh PBMC. The results show that cryopreservation of PBMC at a fairly high cell concentration does not significantly affect cell recovery, viability, or phenotypes of PBMC. After differentiation into DC, iDC and mDC derived from cryopreserved PBMC had their typical phenotypes and function equivalent to those derived from fresh PBMC. Therefore, the improved cryopreservation process of PBMC described in this study is available for DC-based cancer immunotherapy.