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Lower Salinities (lower + salinity)

Distribution by Scientific Domains

Life Sciences	50%
Earth and Environmental Science	50%

Selected Abstracts

Salt-responsive outer membrane proteins of Vibrio anguillarum serotype O1 as revealed by comparative proteome analysis

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2009
D.-Y. Kao
Abstract Aims:,Vibrio anguillarum is a universal marine pathogen causing vibriosis. Vibrio anguillarum encounters different osmolarity conditions between seawater and hosts, and its outer membrane proteins (OMPs) play a crucial role in the adaptation to changes of the surroundings. In the present study, proteomic approaches were applied to investigate the salt-responsive OMPs of V. anguillarum. Methods and Results:, Lower salinity (0·85% NaCl) is more suitable for growth, survival and swimming motility of the bacterium. Comparative two-dimensional electrophoresis (2-DE) analysis reveals six differentially expressed protein spots among three different salinities, which were successfully identified as OmpU, maltoporin, flagellin B, Omp26La, Omp26La and OmpW respectively. Conclusions:, OmpW and OmpU were highly expressed at 3·5% salinity, suggesting their role in the efficient efflux of NaCl. Maltoporin was downregulated in higher salinity, indicating that higher osmolarity inhibits carbohydrate transport and bacterial growth. Omp26La, the homologue of OmpV, functions as a salt-responsive protein in lower salinity. Significance and Impact of the Study:, To the best of our knowledge, this is the first report describing salt stress-responsive proteins of V. anguillarum using proteomic approaches. Our results provide a useful strategy for delineating the osmoregulatory mechanism of the marine pathogens. [source]

Halotaxis of cyanobacteria in an intertidal hypersaline microbial mat

ENVIRONMENTAL MICROBIOLOGY, Issue 3 2010
Katharina Kohls
Summary An intertidal hypersaline cyanobacterial mat from Abu Dhabi (United Arab Emirates) exhibited a reversible change in its surface colour within several hours upon changes in salinity of the overlying water. The mat surface was orange-reddish at salinities above 15% and turned dark green at lower salinities. We investigated this phenomenon using a polyphasic approach that included denaturing gradient gel electrophoresis, microscopy, high-performance liquid chromatography, hyperspectral imaging, absorption spectroscopy, oxygen microsensor measurements and modelling of salinity dynamics. Filaments of Microcoleus chthonoplastes, identified based on 16S rRNA sequencing and morphology, were found to migrate up and down when salinity was decreased below or increased above 15%, respectively, causing the colour change of the mat uppermost layer. Migration occurred in light and in the dark, and could be induced by different salts, not only NaCl. The influence of salinity-dependent and independent physico-chemical parameters, such as water activity, oxygen solubility, H2S, gravity and light, was excluded, indicating that the observed migration was due to a direct response to salt stress. We propose to term this salinity-driven cyanobacterial migration as ,halotaxis', a process that might play a vital role in the survival of cyanobacteria in environments exposed to continuous salinity fluctuations such as intertidal flats. [source]

Effects of salinity on copper accumulation in the common killifish (Fundulus heteroclitus)

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2005
Jonathan Blanchard
Abstract Results of laboratory and field studies have demonstrated that salinity influences the accumulation of copper. The present study is, to our knowledge, the first to examine the effect of salinity on copper accumulation in a teleost fish across a comprehensive range of salinity from freshwater to seawater. This was done in an effort to identify potential target tissues and differences in chemical interactions across salinities that will aid in the development of a seawater biotic ligand model (BLM) for copper. Killifish (Fundulus heteroclitus) were acclimated to five salinities (0, 5, 11, 22, and 28 ppt) and exposed to three copper concentrations (0 [nominal], 30, and 150 ,g L,1), yielding 15 treatment groups. Fish from each group were sampled for tissue copper analysis at 0, 4, 12, and 30 d postexposure. Whole-body and liver accumulations were highest at lower salinities. The liver accounted for 57 to 86% of the whole-body copper even though it accounted for less than 4% of the body mass. Similarly, the gill accumulated more copper at lower salinities, whereas the intestine generally accumulated more copper at higher salinities. Speciation calculations indicate that CuCO3 likely accounts for much of the accumulation, possibly with some contributions from CuOH+ and Cu(OH)2. The free ion, Cu2+, does not appear to be associated with copper accumulation. However, the differences in physiology and in the concentrations of competing cations across salinities suggest that speciation alone cannot explain accumulation. The present findings may have implications for future development of a BLM for saline environments by identifying potential target tissues. [source]

The effect of parental acclimation to spawning salinity on the survival of larval Cynoscion nebulosus

JOURNAL OF FISH BIOLOGY, Issue 3 2002
C. J. Kucera
The yolk and oil depletion of eggs and larvae of spotted seatrout Cynoscion nebulosus, produced by fish collected from two bays with historically different salinity regimes (Matagorda Bay (MB; 18-24%) and Upper Laguna Madre (ULM; 40,50%), Texas, U.S.A. and spawned in salinities of 20, 30 and 40%, differed in their response to both salinity and history. Time to 90% yolk depletion was significantly longer for low salinity bay fish (MB) kept at 20%, but not for high salinity bay fish (ULM) at 20%. The neutral buoyancy salinity of 1 and 2 day old MB 20% larvae was significantly lower than that of MB larvae spawned in 30 or 40%. Overall, eggs and larvae spawned by MB fish were able to hatch out and survive to 3 days post-hatch in lower salinities than those from ULM. Furthermore, the tolerance of eggs and larvae to very low salinities increased with decreasing spawning salinity. The ability of 1,9 day old ULM, but not MB, larvae to survive 18 h exposure to salinities above or below that of spawning exhibited an age-dependent pattern with day 3 being the most sensitive. This study shows that the response of spotted seatrout eggs and larvae to changes in salinity is dependent upon the spawning salinity of the adults and the prevailing salinity regime within the bay. [source]

Effect of Low Salinity on Growth and Survival of Postlarvae and Juvenile Litopenaeus vannamei

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2001
Susan Laramore
The effect of low salinity on survival and growth of the Pacific white shrimp Litopenaeus vannamei was examined in the laboratory due to the interest of raising shrimp inland at low salinities. In three separate experiments, individual L. vannamei postlarvae (, 0.1 g) were cultured at salinities of either 0.5, 1, 1.5, 2, or 3 ppt (N= 5 or 10/treatment) for 18 to 40 d at 30 C in individual 360-mL containers. In each experiment controls of 0 and 30 ppt were run. There was no postlarval survival at salinities < 2 ppt. Survival was significantly different (P < 0.01) at 2 ppt (20%) compared to 30 ppt (80%). Growth was also significantly different (P < 0.01) at 2 and 3 ppt compared to 30 ppt (416%, 475%, and 670%, respectively). A fourth experiment compared juveniles (, 8 g) and postlarvae (, 0.05 and 0.35 g). Shrimp were cultured at salinities of 0, 2, 4, and 30 ppt for 40 d at 25 C, in individual 360-mL and 6-L containers (N= 7/treatment). There was no postlarval survival at < 2 ppt. Postlarval survival at 4 ppt (86%) was not significantly different (P > 0.05) from 30 ppt (100%). Juveniles exhibited better survival at lower salinities (100% at 2 ppt) than 0.05 and 0.35 g postlarvae (29% and 14% respectively, at 2 ppt). The effects of salinity on growth varied with sizdage. Final growth of 0.05 g postlarvae at 2 ppt (693%) was significantly less (P < 0.01) than at 4 ppt (1085%) and 30 ppt (1064%). Growth of 0.35 g postlarvae was significantly less (P < 0.01) for 4 ppt (175%) than for 30 ppt (264%). There was no growth data for juveniles (8 g). It appears from these experiments that the culture of L. vannamei poses risks when performed in salinities less than 2 ppt. [source]

Physiological responses of pink abalone Haliotis corrugata (Gray, 1828) exposed to different combinations of temperature and salinity

AQUACULTURE RESEARCH, Issue 7 2010
Zarina Medina Romo
Abstract Physiological responses of pink abalone Haliotis corrugata were determined under different temperature and salinity conditions. Oxygen consumption rate was not affected by temperature and salinity. Ammonium excretion of pink abalone was inversely related to salinity. The O:N ratio indicated that abalone maintained in lower salinities had an interval of 4.9,7.7, which is indicative of a protein-dominated metabolism, whereas the O:N in 35, was 28.8,35.5 for both temperatures, suggesting that carbohydrates were used as energy substrate. Haemolymph osmolality of abalone exposed to 20 and 24 °C was slightly hyperiso-osmoconformic in salinity ranges of 20,35,. The results of this study suggested that for optimized culture, pink abalone should be cultivated at 24 °C at a salinity of 35,. [source]

Acute tolerance of juvenile Florida pompano, Trachinotus carolinus L., to ammonia and nitrite at various salinities

AQUACULTURE RESEARCH, Issue 9 2006
Charles R Weirich
Abstract The acute tolerance of juvenile Florida pompano Trachinotus carolinus L. (mean weight±SE=8.1±0.5 g) to environmental unionized ammonia-nitrogen (NH3 -N) and nitrite-nitrogen (NO2 -N) at various salinities was determined via a series of static exposure trials. Median-lethal concentrations (LC50 values) of NH3 -N and NO2 -N at 24, 48, and 96 h of exposure were calculated at salinities of 6.3, 12.5 and 25.0 g L,1 at 28 °C (pH=8.23,8.36). Tolerance of pompano to acute NH3 -N exposure was not affected by salinity, with 24, 48 and 96 h LC50 values ranging from 1.05 to 1.12, 1.00 to 1.08 and 0.95 to 1.01 mg NH3 -N L,1 respectively. Regarding NO2 -N, tolerance of pompano to this environmental toxicant was compromised at reduced salinities. Median-lethal concentrations of NO2 -N to pompano at 24, 48 and 96 h of exposure ranged from 67.4 to 220.1, 56.9 to 140.7 and 16.7 to 34.2 mg NO2 -N L,1 respectively. The results of this study indicate that juvenile Florida pompano are relatively sensitive to acute NH3 -N and NO2 -N exposure, and in the case of the latter, especially at lower salinities. [source]

Salt-responsive outer membrane proteins of Vibrio anguillarum serotype O1 as revealed by comparative proteome analysis

Influence of salinity, competition and food supply on the growth of Gobiosoma robustum and Microgobius gulosus from Florida Bay, U. S. A.

JOURNAL OF FISH BIOLOGY, Issue 4 2004
P. J. Schofield
The code Gobiosoma robustum and clown Microgobius gulosus gobies were grown in the laboratory over 27 days at two salinities (5 and 35), two food levels [low (a fixed proportion of initial mass) and high (saturation)] and both with and without the presence of the other species. Both species exhibited greatest growth at the high food level and the low (5) salinity. Neither species was affected by the presence of the other species, and there were no overall differences in growth between the two species. Thus, the observed competitive superiority of G. robustum over M. gulosus does not seem to confer an advantage relative to feeding success. Furthermore, as growth of G. robustum was greater at the lower salinity, it is clear that some factor other than salinity is restricting this species from north-eastern Florida Bay. Additional work on the importance of predation and food resources in various regions of Florida Bay is needed to further evaluate the underlying mechanisms responsible for the bay-wide distribution of these species. [source]

CYST,THECA RELATIONSHIP, LIFE CYCLE, AND EFFECTS OF TEMPERATURE AND SALINITY ON THE CYST MORPHOLOGY OF GONYAULAX BALTICA SP.

JOURNAL OF PHYCOLOGY, Issue 4 2002
NOV. (DINOPHYCEAE) FROM THE BALTIC SEA AREA
A new species of Gonyaulax, here named Gonyaulax baltica sp. nov., has been isolated from sediment samples from the southeastern Baltic. Culture strains were established from individually isolated cysts, and cyst formation was induced in a nitrogen-depleted medium. Although G. baltica cysts are similar to some forms attributed to Spiniferites bulloideus and the motile stage of G. baltica has affinities with G. spinifera, the combination of features of cyst and motile stage of G. baltica is unique. The culture strains were able to grow at salinity levels from 5 to 55 psu and formed cysts from 10 to 50 psu. Cultures at each salinity level were grown at 12, 16, and 20° C. Temperature- and salinity-controlled morphological variability was found in the resting cysts. Central body size varied with temperature and salinity, and process length varied with salinity. Cysts that formed at extreme salinity levels displayed lower average process length than cysts formed at intermediate salinity levels, and central body length and width were lowest at higher temperature and lower salinity. Models for the relationship between central body size and temperature/salinity and process length and salinity have been developed and may be used to determine relative paleosalinity and paleotemperature levels. Our results on salinity-dependent process length confirm earlier reports on short-spined cysts of this species found in low salinity environments, and the model makes it possible to attempt to quantify past salinity levels. [source]