Search

Experiments were conducted to identify factors involved in sex change in the protogynous black sea bass Centropristis striata. Black sea bass maintained in the ratio of 8 females (F):0 males (M) for 9 months reversed sex while those kept at the ratios of 6F:2M or 4F:4M did not. Female black sea bass implanted with 1·0 mg 11-ketotestosterone (11-KT) or 10 mg fadrozole (FAD) changed sex and began spermiating while those implanted with 0·1 mg 11-KT or 1·0 mg FAD underwent incomplete sex reversal. One fish implanted with 1·0 mg FAD initiated sex change but was not spermiating at the end of the study. One fish in the control group, the largest fish in the study, initiated sex change. These results suggest that the presence of males may restrict sex reversal in black sea bass and that high 17β-oestradiol:11-KT is required for maintaining ovarian function. [ABSTRACT FROM AUTHOR]

Increasing hatchery raceway flow to a rate similar to that seen in nature exercises salmon in the expectation that improving swimming ability will result in better survival. However, insufficient water prevents most hatcheries from fully simulating natural stream currents. We examined the effect of moderate and seasonally variable flow rates (0.25-0.75 body lengths/s) on growth and physiology of juvenile Chinook salmon and their ability to withstand acute stress, survive downstream migration, and return as adults. Changes in salmon growth, condition, and hematocrit followed similar patterns and did not substantially vary between treatments or cohorts. Patterns of change in plasma glucose levels were also similar for each treatment. Hepatosomatic index was higher in the 1994 cohort than in the 1995 cohort and in the exercised salmon. Liver glycogen levels were higher in the 1995 cohort. Plasma glucose and cortisol levels increased after stress and were greater in the control. Hematocrit decreased following stress but did not differ between cohorts or treatments. Hepatosomatic index decreased following stress and was higher in the 1994 cohort. Liver glycogen levels did not change following stress or between treatments but were greater in the 1995 cohort. Downstream survival did not vary between cohorts or treatments. Migration time did not vary between treatments, but the 1995 cohort migrated more quickly. Harvest and stray rates were very low and did not vary between cohorts or treatments. Hatchery return, total return, and total survival rates did not vary between treatments, but the 1995 cohort had greater survival. A greater percentage of the exercised salmon returned at age 3 than was the case for the control salmon. Our results provide little evidence that rearing Chinook salmon under a moderately increased and seasonally variable flow regime confers any benefit to the salmon over that derived from a steady, low flow rate. [ABSTRACT FROM AUTHOR]

Growth of haddock (Melanogrammus aeglefinus) was assessed in onshore tanks in West Scotland. Fish were stocked at a mean weight of 15g in July 2002, with a second stocking in October 2002 at 25g. Fish had a mean weight of 755±150 (s.d.) g at 20 months after stocking and were harvested. The specific growth rate of haddock was similar to Atlantic cod (Gadus morhua) during the first year but decreased by 20% after that. Liver biomass was 17.6% of the whole body weight, suggesting haddock had difficulty in utilizing dietary lipid. Reduced lipid levels in the diet had only a short-term effect on hepatosomatic index (HSI). Haddock that were held under 24-h light from the first summer solstice did not mature at an age of two years when compared with complete maturation of fish reared under ambient light. Mortality during the on-growing stage was high (28% of stock) and was attributed to Vibrio anguillarum infection, and possibly to enlarged livers. An assessment of quality found taste and texture to be as good or equal to wild North Sea haddock, and quality was improved with a five-day starvation period. Haddock mean weight, six months after transfer to netpens, was not significantly different from that of fish of the same age grown in tanks. [Copyright &y& Elsevier]

We review photonic applications of dielectric whispering-gallery mode (WGM) resonators-tracing the growth of the technology from experiments with levitating droplets of aerosols to ultrahigh-Q solid state crystalline and integrated on-chip microresonators. [ABSTRACT FROM PUBLISHER]

In this study we use a taxon-based approach to examine previous, as well as new findings on several topics pertaining to the peripheral olfactory components in teleost fishes. These topics comprise (1) the gross anatomy of the peripheral olfactory organ, including olfactory sensory neuron subtypes and their functional parameters, (2) the ultrastructure of the olfactory epithelium, and (3) recent findings regarding the development of the nasal cavity and the olfactory epithelium. The teleosts are living ray-finned fish, and include descendants of early-diverging orders (e.g., salmon), specialized descendants (e.g., goldfish and zebrafish), as well as the Acanthopterygii, numerous species with sharp bony rays, including perch, stickleback, bass and tuna. Our survey reveals that the olfactory epithelium lines a multi-lamellar olfactory rosette in many teleosts. In Acanthopterygii, there are also examples of flat, single, double or triple folded olfactory epithelia. Diverse species ventilate the olfactory chamber with a single accessory nasal sac, whereas the presence of two sacs is confined to species within the Acanthopterygii. Recent studies in salmonids and cyprinids have shown that both ciliated olfactory sensory neurons (OSNs) and microvillous OSNs respond to amino acid odorants. Bile acids stimulate ciliated OSNs, and nucleotides activate microvillous OSNs. G-protein coupled odorant receptor molecules (OR-, V1R-, and V2R-types) have been identified in several teleost species. Ciliated OSNs express the G-protein subunit Gαolf/s, which activates cyclic AMP during transduction. Localization of G protein subunits Gα0 and Gαq/11 to microvillous or crypt OSNs, varies among different species. All teleost species appear to have microvillous and ciliated OSNs. The recently discovered crypt OSN is likewise found broadly. There is surprising diversity during ontogeny. In some species, OSNs and supporting cells derive from placodal cells; in others, supporting cells develop from epithelial (skin) cells. In some, epithelial cells covering the developing olfactory epithelium degenerate, in others, these retract. Likewise, there are different mechanisms for nostril formation. We conclude that there is considerable diversity in gross anatomy and development of the peripheral olfactory organ in teleosts, yet conservation of olfactory sensory neuron morphology. There is not sufficient information to draw conclusions regarding the diversity of teleost olfactory receptors or transduction cascades. [ABSTRACT FROM AUTHOR]

The propagation velocity of turbulent premixed flames with real thermal expansion in a time-dependent external flow is studied for an infinitely thin flame front and for flames of small but finite thickness. It is shown that the influence of temporal pulsations is usually small and can be neglected for reasonable values of the pulsation frequency. The role of pulsations is even smaller for realistic thermal expansion in comparison with the artificial case of zero thermal expansion studied previously. The results obtained indicate that the Taylor hypothesis of “ stationary” turbulence is a good approximation for turbulent flames. The role of pulsations is substantial only if the integral turbulent length scale is close to the cut-off wavelength of the Darrieus-Landau instability. In this particular case, temporal pulsations can be important for explaining recent experiments on turbulent burning. [ABSTRACT FROM AUTHOR]

Concerns about access to oil supplies have encouraged the exploration of renewable fuel and energy sources. Industrial ecology offers tools to compare the energy implications and benefits of differing strategies, but using botanical sources of raw materials to replace nonrenewable ones also requires appreciation of plant science, especially the variation in genetic potential within species. Whereas cultivation methods determine whether genetic potential is realized, different methods impact the environment to varying degrees. Experience with barley variety mixtures, aimed at reducing chemical input, has shown them to improve yield and reduce disease, while maintaining or even enhancing quality. Yield improvements still occurred in the absence of disease and increased in proportion to the number of component varieties. Because other research showed mixtures to be similarly effective in wheat, a protocol to grow and exploit a complex mixture of soft wheat is proposed, offering a cost-effective and energy efficient feedstock for a possible bioethanol industry in the United Kingdom. Ethanol would be produced initially from grain, with the straw used for heating or electricity generation. Fertilizer production and use and vehicle fuels have been shown as the main forms of energy consumption in growing a crop, and targets for enhancing the energy balance, by growing mixtures under an integrated farming system, are postulated. A close but negative association between grain protein and alcohol yield is demonstrated and a mixture giving comparable grain yield, but superior alcohol yield, to its best component is identified. Mixing varieties differing in plant morphology may also increase total biomass yield and, therefore, the energy generated from the crop. Pesticide reduction has another positive, though small, effect on the energy balance, from using mixtures. Eliminating prophylactic spraying also reduces vehicle fuel consumption, and may provide the low-toxicity benefits of organic agriculture without the yield penalty. A range of alternative uses for straw and other by-products is also discussed. [ABSTRACT FROM AUTHOR]

During the past 150 years, researchers have investigated the cellular, physiological, and molecular mechanisms underlying the sense of smell. Based on these efforts, a conclusive model of olfactory signal transduction in the vertebrate's nose is now available, spanning from G-protein-mediated odorant receptors to ion channels, which are linked by a cyclic adenosine 3',5'-monophosphate-mediated signal transduction cascade. Here we review some historical milestones in the chronology of olfactory research, particularly emphasising the role of cyclic nucleotides and inositol trisphosphate as alternative second messengers in olfactory cells. We will describe the functional anatomy of the nose, outline the cellular composition of the olfactory epithelium, and describe the discovery of the molecular backbone of the olfactory signal transduction cascade. We then summarize our current model, in which cyclic adenosine monophosphate is the sole excitatory second messenger in olfactory sensory neurons. Finally, a possible significance of microvillous olfactory epithelial cells and inositol trisphosphate in olfaction will be discussed. [ABSTRACT FROM AUTHOR]

To evaluate the performance of Seneca and Marquette strains of lake trout Salvelinus namaycush for restoring stocks in southern Lake Michigan, we compared relative abundance (fish per lift of 305 m of gill net), survival (slope of the decline in natural logarithms of relative abundance), growth (von Bertalanffy growth curves), and wounding rates by sea lamprey Petromyzon marinus of the 1984 and 1985 year-classes captured at ages 3-16 in fall gill-net assessments on the Sheboygan Reef and the Milwaukee nearshore area during 1987-2000. Marquette strain lake trout survived at a significantly higher rate than Seneca strain lake trout prior to age 3 but at similar rates after age 3. The 1984 year-class of lake trout survived at a significantly higher rate than the 1985 year-class of lake trout prior to age 3 but at similar rates after age 3. Emigration of lake trout from the Sheboygan Reef to the nearshore Milwaukee area was similar for the Marquette and Seneca strains but was higher for the 1984 year-class than the 1985 year-class. The mean relative abundance of the 1984 and 1985 year-classes of Marquette and Seneca strains of lake trout varied erratically with age but did not decline with age on the Sheboygan Reef and Milwaukee nearshore area. On the Sheboygan Reef, growth in length, expressed as asymptotic length (La), differed significantly between the Marquette and Seneca strains of lake trout but did not differ significantly between the 1984 and 1985 year-classes. On the Sheboygan Reef, wounding rates by sea lampreys did not differ significantly between the Marquette and Seneca strains of lake trout among size-classes (633-734, 735-836, and ≥837 mm) during 1994-2000. Our findings suggest that the performance of Marquette strain lake trout was superior to that of Seneca strain lake trout on the Sheboygan Reef in central Lake Michigan. [ABSTRACT FROM AUTHOR]

The paper describes a large eddy simulation model of gaseous deflagration in a closed vessel and simulation results for stoichiometric hydrogen-air premixed combustion initiated at the center of a closed 6.37-m³ spherical vessel. The model is based on the large eddy simulation approach to turbulence modeling and the gradient method to model the mass burning rate in premixed combustion. The method for simulated flame-front thickness reduction is suggested, and its performance is investigated. The solution-adaptive mesh refinement is used to decrease the CPU time required for simulation. The simulated deflagration-pressure dynamics is in agreement with published experimental data, and the flame-front velocity is in agreement with simulation results obtained according to the lumped parameter model for the same experiment. [ABSTRACT FROM AUTHOR]

It is difficult to over-state the importance of Zn(II) in biology. It is a ubiquitous essential metal ion and plays a role in catalysis, protein structure and perhaps as a signal molecule, in organisms from all three kingdoms. Of necessity, organisms have evolved to optimise the intracellular availability of Zn(II) despite the extracellular milieu. To this end, prokaryotes contain a range of Zn(II) import, Zn(II) export and/or binding proteins, some of which utilise either ATP or the chemiosmotic potential to drive the movement of Zn(II) across the cytosolic membrane, together with proteins that facilitate the diffusion of this ion across either the outer or inner membranes of prokaryotes. This review seeks to give an overview of the systems currently classified as altering Zn(II) availability in prokaryotes. [Copyright &y& Elsevier]

The MerR family is a group of transcriptional activators with similar N-terminal helix-turn-helix DNA binding regions and C-terminal effector binding regions that are specific to the effector recognised. The signature of the family is amino acid similarity in the first 100 amino acids, including a helix-turn-helix motif followed by a coiled-coil region. With increasing recognition of members of this class over the last decade, particularly with the advent of rapid bacterial genome sequencing, MerR-like regulators have been found in a wide range of bacterial genera, but not yet in archaea or eukaryotes. The few MerR-like regulators that have been studied experimentally have been shown to activate suboptimal σ70-dependent promoters, in which the spacing between the −35 and −10 elements recognised by the σ factor is greater than the optimal 17±1 bp. Activation of transcription is through protein-dependent DNA distortion. The majority of regulators in the family respond to environmental stimuli, such as oxidative stress, heavy metals or antibiotics. A subgroup of the family activates transcription in response to metal ions. This subgroup shows sequence similarity in the C-terminal effector binding region as well as in the N-terminal region, but it is not yet clear how metal discrimination occurs. This subgroup of MerR family regulators includes MerR itself and may have evolved to generate a variety of specific metal-responsive regulators by fine-tuning the sites of metal recognition. [Copyright &y& Elsevier]

Electro-olfactogram (EOG) recordings from female Mozambique tilapia Oreochromis mossambicus gave large responses (up to 45 mV) to water previously occupied by sexually active males. Male body-fluids also elicited very strong olfactory responses with thresholds of detection of c. 1 : 106·9 (bile), 1 : 105·2 (urine) and 1 : 104·9 (faeces). Considering the likely rates of release of these fluids, it is the urine that provides the strongest olfactory stimulus for females. Crude fractionation of the male water and body-fluids implicated: (a) sulphated compounds, possibly steroids, as the most potent odorant in the urine (and water previously occupied by males), and (b) bile acids in the faeces and bile. Although the olfactory system of Mozambique tilapia was found to be sensitive to a range of amino acids and bile acids, steroids present in Mozambique tilapia plasma and steroids known to act as pheromones in other species elicited negligible responses. Although the present study clearly suggests that chemical communication might be important in Mozambique tilapia, the exact chemical identity of the compounds involved, and their biological functions, remain to be elucidated.Copyright 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

Pale-grey cells appeared in the livers of healthy and non-stressed brown trout Salmo trutta 3 weeks post-hatching whereas interhepatocytic macrophages appeared at 5 months. Cells with intermediate morphological characteristics between those of pale-grey cells and macrophages were identified in all ages studies. Cell ultrastructure supported the idea that pale-grey cells probably belonged to the macrophage lineage, being eventual precursors of the active phagocytes residing amongst hepatocytes. Copyright 2002 The Fisheries Society of the British Isles. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

A study was undertaken to examine the effect of different amounts of dietary lysine (13 and 21 g kg-1 diet), lipid (80 and 160 g kg-1 diet) and L-carnitine (0.2 and 1.0 g kg-1 diet) on growth performance, proximate composition and amino acid metabolism of the African catfish (Clarias gariepinus ). Juvenile African catfish (23 ± 1.5 g/fish) were stocked into 70-L aquaria (16 aquaria, 28 fish/aquarium) connected to a recirculation system during a maximum period of 74 days. All groups were fed at a level of 24 g kg-0.8 day-1 in an experiment run at pair feeding. Animals receiving 1.0 g carnitine accumulated up to six times more carnitine in their tissues than animals receiving 0.2 g (P < 0.05). Acyl-carnitine and free L-carnitine levels increased in the whole body and in tissues. Dietary L-carnitine supplements increased protein-to-fat ratios in the body, but did not affect growth rate. Protein-to-fat ratios were only affected when the biosynthesis capacity of L-carnitine was restricted due to low lysine levels and when there was a shortage of dietary fat. When lysine was offered at 21 g kg-1 feed, dietary L-carnitine supplements did not affect the amino acid concentrations of body tissues. Dietary L-carnitine supplements raised the concentration of glutamic acid > aspartic acid > glycine > alanine > arginine > serine > threonine in skeletal muscle tissue (P < 0.05). Total amino acid concentration in muscle and liver tissues (dry-matter basis) increased from 506 to 564 and from 138 to 166 mg g-1 , respectively, when diets were offered with high L-carnitine, low lysine and low fat levels. These data suggest that dietary L-carnitine supplementation may increase fatty acid oxidation and possibly decrease amino acid combustion for energy. [ABSTRACT FROM AUTHOR]

Activation of the Escherichia coli SoxRS-regulon by nitric oxide (NO) and its physiological donors (S-nitrosothiol (GS-NO) and dinitrosyl iron complexes with glutathione (DNICglu) and cysteine (DNICcys) ligands) has been studied. To elucidate the molecular mechanisms of signal transduction via nitrosylation of Fe-S-centers in SoxR, the ability of pure NO and NO-producing agents to activate the SoxRS-regulon in E. coli cells bearing a soxS:: lacZ operon (promoter) fusion has been compared. EPR spectroscopy of whole cells has been used to monitor the formation of inducible protein–DNIC complexes. DNICcys, GS-NO, and pure NO appeared to be potent inducers of soxS expression, whereas DNICglu was considerably less efficient. Thus, lower in vitro stability of DNICcys was in contrast with its higher biological activity. Pretreatment of the cells with o-phenanthroline, a chelating agent for iron, prevented soxS expression by GS-NO. Treatment of intact E. coli cells with DNIC, GS-NO, and NO at equimolar concentration 150 μM resulted in formation of a single EPR-detectable DNIC-type signal with g = 2.03. The initial stage in the SoxR transcription activity is supposed to include two steps: first, DNIC primers are formed from exogenous NO and free iron, and then these DNIC disintegrate SoxR [2Fe-2S] clusters and thus activate SoxRS-regulon transcription. [ABSTRACT FROM AUTHOR]

Viruses of lower vertebrates recently became a field of interest to the public due to increasing epizootics and economic losses of poikilothermic animals. These were reported worldwide from both wildlife and collections of aquatic poikilothermic animals. Several RNA and DNA viruses infecting fish, amphibians and reptiles have been studied intensively during the last 20 years. Many of these viruses induce diseases resulting in important economic losses of lower vertebrates, especially in fish aquaculture. In addition, some of the DNA viruses seem to be emerging pathogens involved in the worldwide decline in wildlife. Irido-, herpes- and polyomavirus infections may be involved in the reduction in the numbers of endangered amphibian and reptile species. In this context the knowledge of several important RNA viruses such as orthomyxo-, paramyxo-, rhabdo-, retro-, corona-, calici-, toga-, picorna-, noda-, reo- and birnaviruses, and DNA viruses such as parvo-, irido-, herpes-, adeno-, polyoma- and poxviruses, is described in this review. [ABSTRACT FROM AUTHOR]

In the review contemporary data on the effects of oxidative stresses of various kinds in bacteria are summarized. A general theory of oxidative stress, peculiarities of oxidative stress in eukaryotes and prokaryotes, and natural and induced oxidative stresses are described. Data on the mechanisms of protection against oxidative stress are given, including prevention of the generation of oxidative stress, prevention of propagation of free radical chain reactions, and the mechanisms of repair of damaged DNA. The regulation of effector genes via redox-sensitive iron-containing proteins is analyzed. Special attention is given to the expression of so-called antioxidant and associated enzymes as protection mechanisms and to the space–time organization of the response of bacteria to oxidative stress. [ABSTRACT FROM AUTHOR]

When odorants bind to the sensory cilia of olfactory sensory neurons, the cells respond with an electrical output signal, typically a short train of action potentials. This review describes the present state of knowledge about the olfactory signal transduction process. In the last decade, a set of transduction molecules has been identified which help to explain many aspects of the sensory response. Odor-induced second-messenger production, activation of transduction channels, the central role of the ciliary Ca2+ concentration, as well as mechanisms that mediate adaptation, are all qualitatively understood on the basis of a consistent scheme for chemoelectrical transduction. This scheme, although necessarily incomplete, can serve as a working model for further experimentation which may reveal kinetical aspects of signal transduction processes in olfactory sensory neurons. [ABSTRACT FROM AUTHOR]

Reports on the structure of multidrug transporter in Bacillus subtilis in complex with the drug tetraphenylphosphonium and a 22-base-pair oligodeoxynucleotide encompassing the promoter. The efflux chemically diverse drugs by multidrug transporters, which is one mechanism of multidrug resistance in bacteria; How the structure reveals an unexpected mechanism for transcription activation.

A study was undertaken to investigate the effects of graded dietary levels and different types of carnitine on hybrid striped bass ( Morone chrysops ♀ × M. saxatilis ♂ %) fed different levels of lipid. An incomplete factorial design was utilized in which diets containing lipid at either 5 or 10% were supplemented with l-carnitine at 0, 500, or 1000 mg kg−1 diet, dl-carnitine at 1000 mg kg−1 diet, or carnitine chloride to provide 1000 mg carnitine kg−1 diet. Juvenile hybrid striped bass (3.3 g fish−1) were stocked into individual 38-l aquaria connected as a brackish water (6‰), recirculating system and fed each diet in triplicate for 9 weeks. Supplementation of the diet with 1000 mg carnitine kg−1 increased muscle carnitine from 35.5 to 47.7 μg g−1 tissue. Carnitine supplementation did not result in increased weight gain regardless of carnitine level or type; however, weight gain showed a significant ( p<0.05) response to dietary lipid with fish fed diets containing 10% lipid growing 34% more than fish fed diets with 5% lipid. The hepatosomatic index also was unaffected by diet, but the intraperitoneal fat (IPF) ratio was significantly elevated (5.1 vs 3.2%) in fish fed diets with 10% lipid compared to those fed diets with 5% lipid. Fish fed diets containing 1000 mg carnitine kg−1 had increased IPF ratio values at 4.7% compared to 3.9% for fish fed the basal diet. Liver lipid also was responsive to dietary treatment, increasing from 6.7 to 8.8% of wet weight as dietary lipid increased from 5 to 10%. The relative quantities of triglycerides, free fatty acids and phospholipids in muscle and liver were not influenced by carnitine level, carnitine type or dietary lipid level. Supplementation of carnitine does not appear to be beneficial to hybrid striped bass based on either growth performance or body composition. [ABSTRACT FROM AUTHOR]

The article reports on the distribution records for herpetofauna of Louisiana as of December 2015. These include Brown Anole at Buckhorn Wildlife Management Area (WMA), Rio Grande Chirping Frog found at Alexander State Forest WMA, Mole Salamander at Boeuf WMA, and Timber Rattlesnake at Sicily Island Hills WMA.

Superoxide (O2 ) poses multiple threats, which are diminished by a family of metalloenzymes, the superoxide dismutases. Among the damaging effects of O are direct oxidation of low-molecular2 weight reductants; inactivation of a select group of enzymes; and reaction with NO to yield the strong oxidant, peroxynitrite. Of even greater import is the ability of O to univalently oxidize the [4 Fe2 4 S] clusters of dehydratases, which causes release of iron. The "free" iron, which is kept reduced by cellular reductants, then reduces hydroperoxides to hydroxyl or alkoxyl radicals. Because the "free" iron will preferentially bind to anionic polymers, such as nucleic acids, or to anionic surfaces, such as cell membranes, these radicals will be generated adjacent to these vital targets and will preferentially attack them. O and iron can thus be viewed as part2 ners in crime, and reciprocal regulatory effects between iron and O2 may be anticipated. These are discussed. [ABSTRACT FROM AUTHOR]

Presents a study which assessed the environmental knowledge and attitudes of high school students from a questionnaire administered before and after exposure to a 10-day environmental science course. Methodology; Results of the study; Correlation between student attitudes and knowledge.

SoxS is a transcrjptional activator of oxidative stress genes in Escherichia coli. SoxS in vitro binds the promoters of soxRS-regulated genes such as micF, zwf, nfo and soda, forms multiple protein-DNA complexes, and recruits RNA polymerase to the promoters. E. coli Rob protein, with an N-terminus 55% identical to SoxS, was initially identified by its binding to the oriC replication origin, but Rob in vitro binds some of the same promoters as SoxS and in vivo activates some SoxS-regulated genes. In this work we show that the multiple complexes with SoxS arise from the presence at least two independent binding sites in each of the micF and zwf promoters. SoxS and Rob each form only a single complex with a 20 bp DNA oligonucleotide corresponding to the region immediately upstream of the -35 element of the micF promoter. Methylation interference identified several conserved purine residues required for binding to micF and five other SoxS-binding sites. Together with binding studies using mutated oligonucleotides and published DNase I footprinting data, this information was used to form a consensus for SoxS sequence specificity: AN2GCAYN7CWA (where N is any base, Y is a pyrimidine, and W is A or T). The sequence requirements for Rob binding differed somewhat from those of SoxS. Using the SoxS-binding consensus, several genes potentially regulated by soxRS were identified in an E. coli genomic database; some of these genes have functions that might contribute to cellular resistance to oxidative stress. [ABSTRACT FROM AUTHOR]

High levels of mortalities have been experienced in farmed coho salmon, Oncorhynchus kisutch (Walbaum), in the Gulf of Ancud, southern Chile. Most affected fish had similar skin lesions ranging from small areas of raised scales through white raised plaques to shallow ulcers. The fish were also generally dark, lethargic and anorexic. However, some affected fish appeared grossly normal with no skin lesions. Internal pathology consisted of varying degrees of ascites, peritonitis and general pallor. Spleens were generally enlarged. Kidneys and liven were swollen and grey in colour, often with pale focal lesions. Extensive histopathology was present in affected fish with tissue necrosis, intravascular necrotic thrombi, large basophilic cells and basophilic granules, some free in the tissues, some contained within cells. The basophilic granules, known locally as the 'UA', or unidentified agent, were thought to be the main aetiological agent, and are likely to be a rickettsia-like organism. [ABSTRACT FROM AUTHOR]

A rickettsia-like organism (RLO) was isolated from infected coho salmon, Oncorhynchus kisutch (Walbaum), in cultures from six fish cell lines, but could not be cultured on 41 artificial media. The organism was confirmed by Koch's postulates as the aetiological agent of a systemic disease causing significant mortality among coho in Chile. The organism was a Gram-negative, obligate intracellular pathogen frequently observed within intracytoplasmic vacuoles or inclusions of host cells, and appears to belong to the order Rickettsiales, family Rickettsiaceae and possibly the tribe Ehrlichiae. The organism, as well as the clinical signs and pathology it produces, is described. The disease, originally observed only in coho raised in seawater net pens, was reproduced experimentally in fish in both freshwater and seawater aquaria. Horizontal transmission without parasite vectors was observed in fish in both aquaria. The organism was shown, for the first time, to cause disease and mortality in Atlantic, Salmo salar L., and Chinook, O. tshawytscha (Walbaum), salmon and rainbow trout, O. mykiss (Walbaum). Because of the systemic nature of the disease, it is proposed that it be called 'salmonid rickettsial septicaemia'. [ABSTRACT FROM AUTHOR]

The article presents a list of authors who have contributed to various articles published in the November 1984 issue of the "Journal of Fish Diseases." Some of the authors included are J.W. Bernstein, S. Boonyaratpalin, W.A. Rogers, D. Bucke, B. Watermann, S. Feist, A.M. Sutterlin, T.J. Benfey, and many more.

Presents an overview of the different classes of metalloregulatory proteins whose activities are liable to be modulated in response to nitric oxide (NO) production in various species. Synthesis and reactivity of NO; Metal ion-responsive DNA-binding proteins; DNA-binding proteins responsive to or containing heme; Regulatory proteins containing zinc.

Presents news briefs concerning the Canadian Economics Association as of October 1969. Minutes of the annual meeting on June 4-6, 1969; Report of the managing editors of the 'Canadian Journal of Economics'; Papers presented in the meeting.