Showing papers by "University of Stirling published in 1989"
TL;DR: The high-performance thin-layer chromatography method can be applied to lipids extracted from marine organisms including the complex polar lipids derived from phytoplankton and fish neural tissue.
397 citations
TL;DR: In this paper, the entrainment of mixed-size gravel bed material was studied in nine reaches of three high-power streams in Scotland and Norway, and measurements of at-a-point shear stress and bed load transport (by hand-held sampler) were made.
Abstract: Entrainment of mixed size gravel bed material was studied in nine reaches of three high-power streams in Scotland and Norway. Paired measurements of at-a-point shear stress (estimated from velocity profiles) and bed load transport (by hand-held sampler) were made. They extended to very high values (400 N m -2, 3.5 kg m-x s-x). Analyses of maximum bed load diameter, mean bed load diameter, transport rates of individual size fractions, and tracer pebble movements all show some dependence of threshold shear stress for entrainment on absolute particle size, despite strong relative size effects. Precise equal mobility of all sizes was approached in the data set with the highest shear stresses and transport rates. Size-selective transport in the streams studied is also indicated by clear downstream and downbar reductions in surface sediment size over distances too short for abrasion to be significant.
349 citations
TL;DR: In this paper, it was shown that, with an excess of Si over Al and with the formation of hydroxy-aluminosilicate species, the bioavailability of aluminium at pH 5 is reduced and acute toxicity is eliminated.
Abstract: AN increased level of aluminium in acidified natural waters is a primary cause of fish death from damage to gill epithelia and loss of osmoregulatory capacity1–4. Aluminium toxicity depends on the species of aluminium present (cationic, neutral or anionic) and hence is affected by pH and the presence of complexing ligands, such as fluoride, and organic material, such as humic acid, which may ameliorate aluminium toxicity5,6. But silicic acid, Si(OH) 4, present in natural waters as a consequence of the weathering of the aluminosilicates of rocks and soil minerals, has a strong and unique affinity for aluminium7, although its influence on toxicity has not been investigated. Here we show that, with an excess of Si over Al and with the formation of hydroxy-aluminosilicate species, the bioavailability of aluminium at pH 5 is reduced and acute toxicity is eliminated. Silicic acid concentration should therefore be considered as a key parameter in toxicity studies and could be important for the treatment of vulnerable waters.
251 citations
TL;DR: Roles for CNP and MBP at distinct stages of myelin process formation are suggested and support a directive role for the oligodendrocyte's CSK in the formation ofMyelin.
Abstract: Enriched cultures of rat brain oligodendrocytes were extracted with a buffer that separated the cells into a Triton X-100-soluble fraction and an insoluble cytoskeleton (CSK) residue. The buffer was optimised so that intact microtubules were preserved in the CSK residue. The partition of four myelin proteins between the soluble and the CSK fractions was determined by immunoblotting and immunofluorescence. Immunoblotting showed that two integral membrane proteins of myelin, the proteolipid protein (PLP) and the DM-20 protein, were completely extracted under these conditions. By contrast, a substantial amount of myelin basic protein (MBP) and to a lesser extent 2,3-cyclic nucleotide-3-phosphohydrolase (CNP) remained associated with the CSK residue. The association of these proteins with the CSK was confirmed by immunofluorescence. A remarkable difference in the distribution of microfilaments and microtubules was observed in oligodendrocytes. Immature cells possessed many fine processes that were rich in microfilaments. The cell body of these oligodendrocytes was devoid of microfilaments but did contain microtubules. Furthermore, a close association between CNP and microfilaments and between MBP and microtubules was revealed after detergent lysis. The strong interaction between CNP and filamentous actin was underlined by their concomitant disappearance from the extremities of the cell at a later stage of development when extensive membrane sheets had formed. Mature cells had fewer, thicker processes than younger cells and their processes contained microtubules, not microfilaments. MBP was present throughout the thick processes and the membrane sheets. These observations suggest roles for CNP and MBP at distinct stages of myelin process formation and support a directive role for the oligodendrocyte's CSK in the formation of myelin.
179 citations
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TL;DR: The authors argued that workers' bargaining power is influenced by conditions in the external labour market and used British establishment data from 1984 to show that pay depends upon a blend of insider pressure (including the employer's financial performance and oligopolistic position) and outsider pressure, including external wages and unemployment.
Abstract: The paper argues that wage determination is best seen as a kind of rent sharing in which workers' bargaining power is influenced by conditions in the external labour market. It uses British establishment data from 1984 to show that pay depends upon a blend of insider pressure (including the employer's financial performance and oligopolistic position) and outsider pressure (including external wages and unemployment). Lester's feasible 'range' of wages appears typically to be between 8% and 22% of pay. Estimates of the unemployment elasticity of the wage lie in a narrow band around -0.1.
166 citations
TL;DR: It is concluded that artificial control of daylength can improve the supply of eggs and fry for commercial on-growing without any adverse effects on the fecundity of the broodstock or the quality and survival of the eggs and Fry.
146 citations
TL;DR: In this paper, the authors compare the bed load capacity and competence of flow over the predominant gravel bed and over a narrow ribbon of mobile sand which extended alongside the talweg.
Abstract: Measurements in a braided reach of the proglacial White River, Washington, are used to compare the bed load capacity and competence of flow over the predominant gravel bed and over a narrow ribbon of mobile sand which extended alongside the talweg. Analysis of 144 velocity profiles and 222 bed load samples shows that shear stress and roughness height were significantly lower over sand than gravel, but maximum bed load diameter and total gravel transport rate significantly higher, as were transport rates of given size fractions at similar shear stresses. These differences in competence and capacity are explained by relative size effects on the threshold shear stress for entrainment. The influence on gravel transport of local variation in bed material size may explain the self-sorting of “bed load sheets” described by other workers. However, in channels like that described here the continuous longitudinal ribbon of sand allows the flow to develop a lower shear stress over the smoother bed, which partly offsets the relative size effects on competence and capacity.
136 citations
TL;DR: A cDNA for a Trypanosoma brucei cysteine proteinase has been cloned and sequenced and this 108 amino acid extension appears likely to be processed in part to produce the mature enzyme, and may be involved in targetting the protein within the cell.
134 citations
TL;DR: In this article, normative data of intestinal parasite loads in two genera of African primates were presented, i.e., Wild Pan troglodytes and Papio spp.
Abstract: Experimental and clinical parasitology need natural baselines or “controls”. We present normative data intestinal parasite loads in two genera of African primates. Wild Pan troglodytes and Papio spp. were studied at two sites: Gombe in Tanzania (P. anubis) and Mt. Assirik in Senegal (P. papio). Presence or absence of parasites, especially nematodes, was recorded from fecal specimens. Gombe's primates were more often infected than were Mt. Assirik's. At Gombe, but not at Mt. Assirik, chimpanzees seemed to have a higher incidence of infection than baboons. Comparison of three baboon troops yielded apparent differences in prevalence of infection. No differences in infection were found between the wet and dry seasons in Mt. Assirik's chimpanzees.
130 citations
TL;DR: The molecular-species compositions of the diacyl classes of the major phospholipids from the brain and retina of rainbow trout (Salmo gairdneri) were determined and no di-polyunsaturated fatty acid species were found.
Abstract: The molecular-species compositions of the diacyl classes of the major phospholipids from the brain and retina of rainbow trout (Salmo gairdneri) were determined. A total of 46 possible species was identified. Didocosahexaenoyl species were major components of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from retina, comprising 14.1, 41.3 and 28.3% of the respective totals. This species was also abundant in PE and PS from brain, accounting for 14.9 and 19.9% of the totals respectively. Small amounts of di-polyunsaturated fatty acid species [C22:6(n-3) with C20:5(n-3), and C22:6(n-3) with C22:5(n-3)] were also found in these phospholipids. Phosphatidylinositol (PI) from both tissues contained no di-polyunsaturated fatty acid species. Retinal PI contained 40.1% C18:0-C20:4(n-6) with 14.9% of C18:0-C20:5(n-3); brain PI contained 42.3% of C18:0-C20:5 and 10.4% of C18:0-C20:4 species. Brain PC contained a substantial amount of nervonic acid-containing species with the pair C18:1-C24:1/C24:1-C18:1 comprising 8.9% of the total.
124 citations
TL;DR: Two fish oil concentrates were assessed for their ability to generate fatty acid compositions in the cell lines more closely resembling those of intact fish tissues.
Abstract: 1. The incorporation and metabolism of (n-3) and (n-6) polyunsaturated fatty acids (PUFA) supplemented to growing cultures were studied in rainbow trout (RTG-2) and turbot (TF) cell lines. 2. A fatty acid concentration of 20 microM considerably altered the fatty acid composition of the cells without affecting lipid class composition or the appearance of cytoplasmic lipid droplets. 3. Both cell lines exhibited considerable delta 6 desaturase activities. 4. Whereas delta 5 desaturase activity was expressed in RTG-2 cells, delta 4 desaturase activity was absent and, conversely, delta 4 desaturase activity was expressed in TF cells, but there was an apparent deficiency in the C18 to C20 elongase multi-enzyme complex. 5. The delta 6 desaturase activity in both cell lines showed little preference between 18:2(n-6) and 18:3(n-3) but the delta 5 desaturase activity of RTG-2 cells and the delta 4 desaturase activity of TF cells showed a preference for (n-3)PUFA. 6. Two fish oil concentrates were assessed for their ability to generate fatty acid compositions in the cell lines more closely resembling those of intact fish tissues.
TL;DR: Tilapia ( Oreochromis spp.) spermatozoa protected with 12.5% methanol in fish Ringers, stored in 1.5-ml cryotubes and held in a vapour phase liquid nitrogen refrigerator remained viable for at least 13 months showed a high degree of variation; of the 16 samples tested only 66% produced viable cells on thawing.
TL;DR: Only a weak relationship was found between children's intervention in parental quarrels and emotional and behavioral problems, and no other coping strategies were found to predict children's disturbance.
Abstract: Children's reactions to parental quarrels were investigated in a general population sample of children between 9 and 12 years old. One hundred and thirty-nine families participated in the study. Approximately half the children were living in disharmonious families and half were in harmonious families. Mothers and children were interviewed with semistructured interviews to determine how children responded to specific episodes of parental quarrelling. Seventy-one percent of children reported intervening in parental quarrels. A range of other coping strategies was identified: seeking contact with a sibling, confiding in friends, offering comfort to parents after a quarrel, self-blame, seeking information about quarrels, and perceiving beneficial aspects to parental quarrelling. The hypothesis was examined that certain coping strategies would be associated with lower levels of children's behavioral and emotional problems. Only a weak relationship was found between children's intervention in parental quarrels and emotional and behavioral problems. No other coping strategies were found to predict children's disturbance.
TL;DR: The results showed that above a threshold of ca.
TL;DR: Three oilseed meals (mustard, linseed and sesame) of Bangladeshi origin were evaluated as fish meal substitutes in diets of common carp and found that fish fed diets containing higher levels of oilseed protein had significantly higher carcass moisture and lower carcass lipid contents.
Abstract: . Three oilseed meals (mustard, linseed and sesame) of Bangladeshi origin were evaluated as fish meal substitutes in diets of common carp, Cyprinus carpio L. These oilseed meals were included in the diet at various levels (25, 50 and 75% of dietary protein) and the response of fish fed these diets was compared to fish fed a fish meal based control diet (40% protein). On the basis of observed growth rate, food conversion ratio, protein efficiency ratio and apparent net protein utilization, the control diet produced significantly (P< 0.05) the best growth performance. Growth responses were significantly affected by both type and inclusion level of oilseed protein. Of the oilseed proteins tested, the 25% mustard protein and 25% linseed protein diets produced significantly (P< 0.05) better growth performances than higher inclusion levels tested. Apparent protein digestibilities (APDs) for all diets were fairly high, ranging from 77.72 to 89.8O%. In general, APD values decreased with increasing plant protein. Fish fed diets containing higher levels of oilseed protein had significantly (P< 0.05) higher carcass moisture and lower carcass lipid contents. Fish fed 50% mustard protein had histological abnormalities in liver and thyroid tissues. Results are discussed with respect to dietary levels of essential amino acid and anti-nutritional factors.
TL;DR: Results suggest that a more natural housing environment would lead to healthier animals and that mice were less emotional when reared in the more complex cages.
Abstract: To see if a more natural cage design would alter the reactivity of laboratory mice, 192 mice were reared in cages with (1) no dividers, (2) five vertical dividers, (3) nine vertical dividers, or (4) nine vertical dividers and one horizontal platform. The mice preferred the most complex cages, and on almost all measures they were less emotional when reared in the more complex cages. Results suggest that a more natural housing environment would lead to healthier animals.
TL;DR: The morphological and biochemical characteristics of 147 strains of Yersinia ruckeri obtained from Australia, South Africa, North America and Europe were compared and it is suggested that non-motile, Tween hydrolysis negative strains be recognised as Y. r Tuckeri biotype 2.
Abstract: . The morphological and biochemical characteristics of 147 strains of Yersinia ruckeri obtained from Australia, South Africa, North America and Europe were compared. The majority of strains could be divided into coccobacillary organisms or medium sized rods, but this morphological diversity was not correlated with any particular biochemical characteristic. Overall, 18% of strains were non-motile but this was geographically biased in that 23 out of 26 non-motile strains were isolated in the UK. Gelatin and casein hydrolysis, acetoin production, sorbitol fermentation and Tween hydrolysis were the most variable biochemical reactions. Tween hydrolysis reactions differed from the other variable characteristics in that, with the exception of a single motile reference strain, all Tween hydrolysis negative strains were non-motile and vice versa. It is suggested that non-motile, Tween hydrolysis negative strains be recognised as Y. ruckeri biotype 2.
TL;DR: Repetitive challenge by 50% MIC concentrations of 4-quinolone antimicrobials against selective isolation of viable colonies resulted in a 7·2 × increase in resistance in 12 generations, demonstrating the likely outcome of drug misuse.
Abstract: . This paper examines aspects of the resistance of Aeromonas salmonicida isolates to the major fish farming antimicrobials. The antimicrobial resistance of an extensive chronological series of isolates appears to reflect the changing use of different compounds in fish farming since 1969. Repetitive challenge by 50% MIC concentrations of 4-quinolone antimicrobials against selective isolation of viable colonies resulted in a 7·2 × increase in resistance in 12 generations, demonstrating the likely outcome of drug misuse.
TL;DR: It is well established that the lipid content of the herring Clupea harengus undergoes a marked seasonal cycle, being highest during the summer months of active feeding and lowest after a winter fast as mentioned in this paper.
Abstract: It is well established that the lipid content of the herring Clupea harengus from the waters around the British Isles and Ireland undergoes a marked seasonal cycle, being highest during the summer months of active feeding and lowest after a winter fast (Wood, 1958; lies & Wood, 1965; Lovern & Wood, 1937; Molloy & Cullen, 1981; Wallace, 1986). In the case of spring-spawning herring, the minimum lipid content coincides with the spawning period and the depletion of lipid over winter corresponds with the development of gonads (Lovern & Wood, 1937).
01 Nov 1989
TL;DR: The results suggest that protein digestibility values are indicative of amino acid digestibility, however, variation in individual amino acids digestibilities between feed-stuffs means that determination of this parameter may allow more accurate and economical feed formulation.
TL;DR: Groups of fish exposed to both bacteria and to cell-free bacterial extracts showed a significant increase in opercular beat rates, thus demonstrating that they are able to detect the presence of unattached bacteria in suspension.
TL;DR: Generalized anxiety patients were randomly allocated to Cognitive- Behaviour Therapy, Diazepam or Placebo and managed in a primary care setting and the Cognitive-Behaviour group revealed the lowest incidence of subsequent treatment interventions.
Abstract: Generalized anxiety patients were randomly allocated to Cognitive-Behaviour Therapy, Diazepam or Placebo and managed in a primary care setting. Treatments were balanced for degree of psychologist/patient contact. A range of outcome measures, including patient self report, psychologist assessor and general practitioner ratings were used. Large variations within group response to treatment emerged. At the end of active treatment the superiority of Cognitive-Behaviour Therapy was suggested. Post-study psychotropic prescription and psychological treatment was assessed at a 12-month follow-up. The Cognitive-Behaviour group revealed the lowest incidence of subsequent treatment interventions.
TL;DR: Fertilized Atlantic halibut eggs in different developmental stages were sampled from plankton in North Norway in February 1986 and analysed for lipid classes and fatty acid content.
Abstract: Fertilized Atlantic halibut (Hippoglossus hippoglossus L.) eggs in different developmental stages (Days 0 to 18) were sampled from plankton in North Norway in February 1986 and analysed for lipid classes and fatty acid content. In unfertilized ovulated eggs taken from ripe fish caught in 1983/1984, polar and neutral lipids comprised ca. 71 and 30% of the total lipids, respectively, decreasing and increasing to 67 and 33%, respectively, in Stage III (11 to 18 d old) fertilized eggs. Of the polar lipids, phosphatidylcholine decreased markedly from 62% in unfertilized ovulated eggs to ca. 40% in Stage I (0 to 3 d old) fertilized eggs, while phosphatidylethanolamine increased from ca. 7 to 33%. Triacylglycerols, the major neutral lipids, increased from ca. 13% in unfertilized ovulated eggs to 16% in Stage III fertilized eggs. The total lipid in Stage I fertilized eggs had relatively low levels of polyunsaturated fatty acids (PUFA), with (n-3) PUFA accounting for only ca. 25% of the total fatty acids. The (n-3) PUFA increased to ca. 40% of the total fatty acids in Stage III, while the (n-3): (n-6) ratio increased from 4.1 to 7.0.
TL;DR: Des vieillards atteints de fracture du femur sont suivis pendant 1 an, avec ou sans traitement de reeducation specialisee, dans leur ancien domicile.
Abstract: Des vieillards atteints de fracture du femur sont suivis pendant 1 an, avec ou sans traitement de reeducation specialisee. Survie a 1 an: 67% des temoins, 81% des malades reeduques. 69% des malades reeduques peuvent vivre de nouveau dans leur ancien domicile, contre 39% seulement des temoins
TL;DR: Results indicate that a cytoskeletal matrix is associated with multilamellar myelin, and suggest that this structure may play a fundamental role in myelinogenesis.
Abstract: Extraction of rat brain myelin in a buffer containing Triton X-100 yielded a soluble fraction and an insoluble residue that was enriched in cytoskeletal elements. Immunoblot analysis of the detergent-soluble fraction and the insoluble cytoskeletal residue showed that all of the tubulin and more than half of the actin were found within the cytoskeletal fraction. The distribution of myelin-specific proteins was also examined, and revealed that 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) I and most of the myelin basic proteins (MBPs) were equally distributed between both fractions. By contrast, the large MBP (21.5 kDa) and CNPase II (50 kDa) were observed to partition almost entirely with the cytoskeletal fraction. Proteolipid protein was found predominantly in the detergent-soluble fraction, as was DM-20 protein. Analysis of the cytoskeletal fraction by sucrose-density-gradient centrifugation demonstrated that a distinct subset of lipids was tightly bound to the cytoskeletal protein residue. The cytoskeleton-associated lipid was considerably enriched in cerebroside and sphingomyelin by comparison with total myelin lipids. These results indicate that a cytoskeletal matrix is associated with multilamellar myelin, and suggest that this structure may play a fundamental role in myelinogenesis.
TL;DR: In this paper, a 1:1 anation reaction was shown to occur uniquely at a d-H{sub 2}O ligand, and the final agreement was R = 0.059 with 5183 observed reflections.
Abstract: Acid dissociation and water exchange on (Mo{sub 3}O{sub 4}(OH{sub 2}){sub 9}){sup 4+} have been studied by {sup 17}O NMR and UV-visible spectrophotometry in noncomplexing acidic aqueous solution. Exchange at the d-H{sub 2}O ligands, trans to be {mu}{sub 2}-bridging oxygen atoms of the core, occurs readily (k{sub OH}{sup 298}) = 1.6 {times} 10{sup 2} s{sup {minus}1} and much faster than that occurring at the c-H{sub 2}O, trans to the capping oxygen (k{sub OH}{sup 298} = 1.5 {times} 10{sup {minus}3} s{sup {minus}1}). A mechanism of exchange for both waters involving solely the same conjugate base (Mo{sub 3}O{sub 4}OH{sub 2}{sub 8{minus}}(OH)){sup 3+} is relevant. The positive {Delta}S{sup {double dagger}} value (+35 J K{sup {minus}1} mol{sup {minus}1}) for the d-H{sub 2}O exchange and comparison with available data for 1:1 anation reactions of (Mo{sub 3}O{sub 4}(OH{sub 2}){sub 9}){sup 4+} with NCS{sup {minus}} and HC{sub 2}O{sub 4}{sup {minus}} and support for an I{sub d} mechanism. Chemical shifts for both the c- and d-H{sub 2}O {sup 17}O NMR resonances followed as a function of H{sup +} concentration confirmed that the relevant deprotonation occurred uniquely at a d-H{sub 2}O. Values for K{sub a}{sup 298}(Mo{sub 3}O{sub 4}{sup 4+}), determined from the kinetic treatment (0.31 M) and from UV-visible spectrophotometrymore » (0.24 M), were in satisfactory agreement and indicative of high acidity at the d positions. The compound (Mo{sub 3}O{sub 4}(OH{sub 2}){sub 9})(CH{sub 3}C{sub 6}H{sub 4}SO{sub 3}){sub 4} {times} 13H{sub 2}O crystallizes in the monoclinic space group Cc: a = 31.99 (1) {angstrom}, b = 9.886 (2) {angstrom}, c = 17.789 (5) {angstrom}, {beta} = 99.67 (2){degree}. The final agreement was R = 0.059 with 5183 observed reflections. The packing is mainly characterized by the large number of crystallization water molecules and H-bond interactions. It consists of alternate layers of opposite charge.« less
TL;DR: In this article, a strategy formulation procedure for retailers is described, where the changing retail environment has brought problems for some traditional forms of retailing and indeed failure for some stores, but it has also brought opportunities, particularly for the store management that has been prepared to consider different ways of selling.
TL;DR: There was a strong correlation between the in vitro digestibilities obtained and in vitro results (r=+0.99) and an in vitro digestion method developed which simulates the conditions in the digestive tract of carp.