bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of insulin on protein phosphatase 2A expression in muscle in type 2 diabetes
Authors: Højlund K. , Poulsen M. , Staehr P. , Brusgaard K. , Beck‐Nielsen H.
Published: March 2003

Background Protein phosphatase 2A (PP2A) acts on a number of enzymes involved in the insulin regulation of glucose uptake and glycogen synthesis. This study was carried out to investigate the effect of insulin on PP2A expression in skeletal muscles of type 2 diabetic and control subjects.

Material and methods Ten type 2 diabetic and 10 matched, control subjects were studied using the euglycaemic‐hyperinsulinaemic clamp technique combined with indirect calorimetry. Immunoreactive protein levels of the catalytic α subunit of PP2A (PP2A‐Cα) were measured in biopsies from the vastus lateralis muscle obtained in the basal and insulin‐stimulated state.

Results In type 2 diabetic subjects insulin‐mediated glucose disposal, glucose oxidation and nonoxidative glucose metabolism were reduced, whereas lipid oxidation was increased (all P < 0·05). Insulin down‐regulated PP2A‐Cα expression in skeletal muscle of the control subjects (P < 0·05) but not in the type 2 diabetic subjects. In the control subjects, the insulin‐mediated decrease in PP2A‐Cα correlated with the insulin‐mediated increase in glucose disposal, glucose oxidation, nonoxidative glucose metabolism (all P < 0·05) and decrease in lipid oxidation (P < 0·01). In the type 2 diabetic subjects these relationships were absent.

Conclusions Down‐regulation of PP2A‐Cα expression by insulin in skeletal muscle seems to be associated with a normal insulin action on glucose storage, glucose and lipid oxidation. Impaired down‐regulation of PP2A‐Cα expression by insulin may be a marker for insulin resistance and contribute to the pathogenesis of type 2 diabetes.
Ratio between serum IL‐8 and pepsinogen A/C: a marker for atrophic body gastritis
Authors: Sanduleanu S. , Bruïne A. D. E. , Biemond I. , Stridsberg M. , Jonkers D. , Lundqvist G. , Hameeteman W. , Stockbrügger R. W.
Published: March 2003

Background and aims Elevated serum gastrin and a low pepsinogen A/C ratio are well‐recognized markers for atrophic body gastritis (ABG). We have shown that the presence of body atrophy is also associated with elevated serum pro‐inflammatory cytokines. This study tested the hypothesis that serum cytokines provide additional information to gastrin and pepsinogens in screening for ABG.

Methods Two hundred and twenty‐six consecutive patients were investigated on referral for upper gastrointestinal endoscopy: 150 were patients with gastro‐oesophageal reflux disease, receiving acid inhibitory medication either with proton pump inhibitors (n = 113) or with histamine2‐receptor antagonists (n = 37), and 76 were nontreated controls, who had normal endoscopic findings. Gastric mucosal biopsies were sampled for histological examination (Sydney classification). Serum samples were analyzed for gastrin, chromogranin A (CgA), and pepsinogens A and C by RIA, and for the interleukins (IL)‐1β, IL‐6, and IL‐8 by ELISA.

Results Subjects with ABG had significantly higher serum gastrin (P < 0·01) and serum CgA (P < 0·01) levels and significantly lower pepsinogen A/C ratios (P < 0·001) than those without ABG. Additionally, serum IL‐1β, IL‐6 and, especially, IL‐8 levels were significantly higher in the subjects with than in those without ABG (P < 0·0001, for all cytokines). To optimize the detection of body atrophy we defined the ABG index: the ratio between the simultaneously measured IL‐8 and pepsinogen A/C. The area under the ROC curve for the ABG index was significantly greater than that for serum gastrin and for serum pepsinogen A/C alone (0·91 ± 0·029 vs. 0·72 ± 0·042, and vs. 0·83 ± 0·031, P = 0·018 and P = 0·049). Using the ABG index at a cut‐off value of 1·8 pg mL−1, 91% of the cases were classified correctly.

Conclusions The ratio between serum IL‐8 and pepsinogen A/C accurately predicts the presence of ABG. We therefore propose the ABG index as a noninvasive screening test for ABG in population‐based studies.
A nested PCR‐RFLP method for high‐resolution typing of HLA‐A alleles
Authors: Mitsunaga S. , Tokunaga K. , Kashiwase K. , Akaza T. , Tadokoro K. , Juji T.
Published: March 2003

We developed a nested polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) method for high‐resolution typing of HLA‐A alleles. HLA‐A alleles can be identified by this method without the need for other information such as serological type. The first PCR was performed using outer primers, ASP5 and ASP3, specific for the HLA‐A gene, and a 991‐bp DNA fragment extending from exon 1 through exon 3 was amplified. In the second PCRs, exon 2 and exon 3 of the HLA‐A gene were amplified separately from the diluted first PCR product using nested primers. Computer analysis of cleavage patterns for 78 HLA‐A alleles showed that 31 RFLP patterns could be obtained by digestion of the exon 2 PCR product using eight restriction endonucleases and 42 RFLP patterns by digestion of the exon 3 PCR product using 11 restriction endonucleases, and all alleles could be discriminated based on combinations of these RFLP patterns except for nine allele groups or pairs: A*0201/ 0207/ 0215N/0220/0222, A*0205/0208/0214, A*0206/ 0221, A*0212/ 0213, A*2402/2405, A*2406/2413, A*2601 / 2605, A*2603/2606 and A*7401/7402. Thus, 65 PCR‐RFLP patterns were predicted from the results of analysis of digestion patterns of 78 HLA‐A alleles. Among 2145 possible homozygous and heterozygous combinations of the 65 distinguishable PCR‐RFLP patterns, 82 combinations were predicted to have the same PCR‐RFLP patterns. In PCR‐RFLP analysis, although the nested primers were not specific for the HLA‐A gene, clear RFLP banding patterns were obtained because specificity was guaranteed by the use of the outer primers, ASP5 and ASP3 in the first PCR. A*0201 and A*0207 occur relatively frequently in the Asian populations among indistinguishable allele groups or pairs using the present PCR‐RFLP method. We also developed a PCR sequence‐specific primers (PCR‐SSP) method for distinguishing between A*0201/0220/0222 and A*0207/0215N. We could identify 39 alleles (groups) upon HLA‐A typing of 50 Japanese individuals, 40 cell lines of the Fourth Asia‐Oceania Histocompatibility Workshop, and 80 cell lines of the UCLA International Cell Exchange Program using the present PCR‐RFLP and PCR‐SSP methods.
Recognition of HLA‐DR1/DRB1*0101 molecules presenting HLA‐A2 derived peptides by a human recombinant antibody, Fab‐5 A1
Authors: Löffler D. , Welschof M. , Goldmann S. F. , Wölpl A.
Published: March 2003

MHC molecules present peptides in their binding groove to T‐cell receptors inducing proliferation or cytotoxicity of alloreactive T cells. A previously generated human monoclonal antibody (mAb) UL‐5 A1, recognizing a conformational epitope formed by HLA DR1/DRB1*0101 molecules and HLA‐A2 derived peptides, demonstrates T‐cell‐like recognition of the peptide/MHC complex (PMC). To study the genes of the antigen binding region, the nucleotide sequences of the rearranged genes in the variable regions of UL‐5 A1 were determined and the V‐gene usage (VH3, Vλ2) was identified by comparison with published germlines. The genes encoding heavy (Fd) and light (L) chains of UL‐5 A1 were linked and expressed in a bacterial system. Specificity of the recombinant Fab‐5 A1 was determined with HLA‐typed LCLs by flow cytometric analysis. As demonstrated in competitive inhibition assays, UL‐5 A1 and Fab‐5 A1 recognize the same PMC epitope on HLA‐A2+, ‐DR1/DRB1*0101+ typed LCLs. Additionally, mAb UL‐5 A1 and Fab‐5 A1 both recognize HLA‐A2–, ‐DR1/DRB1*0101+ LCLs exogenously loaded with HLA‐A2 peptides (105–117, 103–117). UL‐5 A1‐like antibodies against peptide/MHC complexes could prove valuable tools for research on T‐cell recognition and MHC function.
Strong linkage disequilibrium of TAP1*0301 and TAP2D alleles with the HLA A1‐B35‐DRB1*1104‐DQA1*0103‐DQB1*0603 extended haplotype in Ashkenazi Jews
Authors: Mora B. , Battat S. , Grillo R. , Safirman C. , Israel S. , Brautbar C. , Mazzilli M. C.
Published: March 2003

On the basis of data collected during the 12th International Histocompatibility Workshop, we postulated a possible linkage disequilibrium between the TAP1C allele and the DRB1*1104‐DQA1*0103‐DQB1*0603 haplotype characteristic of Ashkenazi Jews. In order to confirm and extend this preliminary observation, a group of 34 subjects carrying this haplotype was analysed for TAP1 and TAP2 polymorphisms and compared with two control groups sharing either the DRB1 or the DQA1 and DQB1 alleles with the test group. The TAP1*0301 and TAP2D alleles were found to be strongly associated with the entire haplotype, but not with the DRB1*1104 or the DQA1*0103‐DQB1*0603 alleles when carried separately. These data show a strong linkage disequilibrium of TAP1*0301 and TAP2D alleles with the DRB1*1104‐DQA1*0103‐DQB1*0603 haplotype of Ashkenazi Jews, extended on the centromeric and telomeric side to the DPB1*0201 and A1‐B35 alleles, respectively.
Polymorphism in the promoter region of the gene encoding human allograft inflammatory factor‐1
Authors: Turner D. M. , Pravica V. , Sinnott P. J. , Hutchinson I. V.
Published: March 2003

We have identified a new single nucleotide polymorphism within the promoter region of the human allograft inflammatory factor (AIF‐1) gene. The polymorphism, defined by Genbank accession number AF097515, was characterized as a C/T single base pair substitution at position −932. The T allele is associated with both HLA‐DR2 and HLA‐B7. Also, this allele creates the consensus binding site for the E‐box that has high affinity for the basic helix‐loop‐helix (bHLH) family of transcription factors.
PCR‐RFLP typing detects new HLA‐DRB1 alleles: DRB1*13022, DRB1*1336 and DRB1*1435
Authors: Tréjaut J. , Kennedy A. , Hobart D. , Le T. , Greville W. D. , Ng G. , Taverniti A. , Dunckley H.
Published: March 2003

It is difficult to resolve all heterozygous combinations of the HLA‐DRB1*03, *08, *11, *12, *13 and *14 allele group in a one‐step generic HLA‐DRB1 typing system. Therefore, it is common to employ a secondary technique utilizing group‐specific primers to amplify this group of alleles separately from the other HLA‐DRB1, ‐DRB3, ‐DRB4 and ‐DRB5 alleles. This paper describes a polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) method for broad typing of the HLA‐DRB1*03, *08, *11, *12, *13 and *14 alleles which, as well as being time‐efficient and cost‐effective, has so far allowed the detection of 10 new alleles. The new alleles were identified after following up unusual or novel PCR‐RFLP patterns. Of the 10 novel alleles found so far with this method, seven have been described previously while three, DRB1*13022, DRB1*1336 and DRB1*1435, are presented here.
No linkage of the interleukin‐4 receptor locus on chromosome 16p11.2‐12.1 with sarcoidosis in German multiplex families
Authors: Bohnert A. , Schürmann M. , Hartung A. , Hackstein H. , Müller‐Quernheim J. , Bein G.
Published: March 2003

We typed 241 members of 62 sarcoidosis families with 136 affected siblings for three single nucleotide polymorphisms of the interleukin‐4 receptor alpha‐chain gene (IL4R). Allele frequencies in patients were compared to those of healthy unrelated control individuals. The segregation of the three‐point IL4R haplotypes completed by two flanking highly polymorphic microsatellite polymorphisms revealed no evidence for linkage of the IL4R gene locus with sarcoidosis.
Two bi‐allelic single nucleotide polymorphisms within the promoter region of the horse tumour necrosis factor α gene
Authors: Matiašovic J. , Lukeszová L. , Hořín P.
Published: March 2003

Primers based on GenBank sequences within the 5′ untranslated region (UTR) of the human and horse tumour necrosis factor α (TNF‐α) genes were designed and used to amplify a 522‐bp product. Sequencing of five clones derived from five independent PCRs obtained from three different animals of three different breeds (Old Kladruber, Akhal‐Teke and Shetland Pony) revealed a high level of sequence identity to the TNF‐α promoter regions of other species. The existing GenBank horse sequences were confirmed and extended upstream by 230 nucleotides. Based on the sequence obtained, a new horse‐specific forward primer was designed to amplify a 213‐bp PCR product, which was screened for polymorphism using single‐strand conformation polymorphism (SSCP). Three allelic variants of the horse TNF‐α gene were identified and sequenced (GenBank accession numbers ADF 349558–60). Two single nucleotide polymorphisms explained the existence of the three SSCP alleles detected: C/T and T/C single base pair substitutions at positions 137 and 147, respectively. Differences in allelic frequencies between Old Kladruber and Akhal‐Teke breeds were observed.
A novel DRB1*09 allelic sequence in the Jing ethnic minority of China
Authors: Lin J. , Liu Z.‐H. , Chen W. , Jia Z. , Pan D. , Fu Y. , Zhang F. , Xu A.
Published: March 2003

A new DRB1 allele, DRB1*0902, has been identified in an individual of the Jing ethnic minority. Its sequence was confirmed by sequencing of PCR products and clones. This allele differed by three nucleotides from DRB1*09012 at positions 157, 161 and 166, and resulted in amino acid motif substitution from VAES to DAEY.
Unbalanced amounts of HLA‐DQA1 allele mRNA: DQA1*03 shows high and DQA1*0501 low amounts of mRNA in heterozygous individuals
Authors: Donner H. , Seidl C. , Rau H. , Herwig J. , Seifried E. , Usadel K. H. , Badenhoop K.
Published: March 2003

Genes of the HLA‐DR, DQ region confer strong susceptibility to type 1 diabetes mellitus (IDDM). A possible mechanism of susceptibility is a difference in the amounts of transcripts of predisposing and neutral or protective haplotypes. In this study we developed an assay to compare the amounts of mRNA of two distinct HLA‐DQA1 alleles in peripheral blood lymphocytes (PBLs) of heterozygous individuals, using a quantitative RT‐PCR with an internal standard covering all HLA‐DQA1 specifities. We also developed an algorithm to calculate the amounts of mRNA for two distinct alleles in heterozygous individuals based on the comparison to the same internal standard. In total, 37 HLA‐DQA1 heterozygous individuals were analysed, including patients with IDDM (n = 14) and healthy controls (n = 23). Intra‐individually, we observed different amounts of mRNA for different HLA‐DQA1 alleles in the order: HLA‐DQA1*03 > *01 > *0201 > *05. This order was observed in all individuals. We also observed a variation in the ratio of these unbalanced amounts of mRNA in individuals with the same HLA‐DQA1 allele combinations. In all allele combinations the average ratio was increased in patients with IDDM compared to the control samples. HLA‐DQA1*03 positive and DQA1*03, *05 heterozygous patients had the highest average ratios. Nevertheless, based on limited sample numbers, these differences did not reach significance. We therefore conclude that variations between HLA‐DQA1 alleles are not limited to the nucleotide sequence but are also found at the level of amounts of mRNA.
Buffalo (Bubalus bubalis) interleukin‐2: sequence analysis reveals high nucleotide and amino acid identity with interleukin‐2 of cattle and other ruminants
Authors: Sreekumar E. , Premraj A. , Saravanakumar M. , Rasool T. J.
Published: March 2003

A 4400‐bp genomic sequence and a 332‐bp truncated cDNA sequence of the interleukin‐2 (IL‐2) gene of Indian water buffalo (Bubalus bubalis) were amplified by polymerase chain reaction and cloned. The coding sequence of the buffalo IL‐2 gene was assembled from the 5′ end of the genomic clone and the truncated cDNA clone. This sequence had 98.5% nucleotide identity and 98% amino acid identity with cattle IL‐2. Three amino acid substitutions were observed at positions 63, 124 and 135. Comparison of the predicted protein structure of buffalo IL‐2 with that of human and cattle IL‐2 did not reveal significant differences. The putative amino acids responsible for IL‐2 receptor binding were conserved in buffalo, cattle and human IL‐2. The amino acid sequence of buffalo IL‐2 also showed very high identity with that of other ruminants, indicating functional cross‐reactivity.
Analysis of −631 and −475 interleukin‐2 promoter single nucleotide polymorphisms in multiple sclerosis
Authors: Fedetz M. , Alcina A. , Fernández O. , Guerrero M. , Delgado C. , Matesanz F.
Published: March 2003

We have analysed the interleukin‐2 (IL‐2) promoter single nucleotide polymorphisms −475 A/T and −631 G/A, relative to the initiation codon, in patients with multiple sclerosis (MS) and in healthy controls. Both groups showed a very low frequency of T at −475 and A at −631. Our results suggest that these polymorphisms do not contribute to MS susceptibility.
Nitrogen mineralization potential of organomineral size separates from soils with annual straw incorporation
Authors: Christensen B. T. , Olesen J. E.
Published: March 2003

With annual incorporation of straw, soil N mineralization is expected to increase whereby requirements for fertilizer N inputs may be reduced. Samples of whole soil, clay (< 2 μm), silt (2–20 μm) and sand (20–2000 μm) sized organomineral separates from three soils with annual additions of straw ranging from 0 to 12 t ha–1 were leached after 0, 1, 2, 4, 8, 12 and 16 weeks of incubation at 20°C, to determine the content of NH4 + NO3. A three‐pool model using first order kinetics and fixed rate constants (N1, k1 = 0.231 day–1; N2, k2 = 0.00693 day–1; N3, k3 = 0) was fitted to the mineralization data.

The mineralizability of whole soil N (mg N g–1 N) differed among soil types. Straw generally increased the fast N1 and the passive N3 pool while the medium‐term N2 pool was reduced in size. The N1, N2 and N3 averaged 0.8, 2.6 and 96.6% of the whole soil N, respectively.

The N mineralizability increased in the order: sand < silt < clay. The lability of N in a given size separate was almost similar across soil types and straw managements. The active N pools (N1 + N2) averaged 7.1% of the clay N and 2.2% of the silt N. The main difference was related to the N2 pool, which accounted for 5.5% in clay and 1.2% in silt.

Mineral N produced during incubation ranged from 63 to 105 kg N ha–1. Effects of straw disposal were small (< 11 kg N ha–1). Maximum response was at 4 t straw ha–1; adding more straw diminished mineralization of N.

Long‐term annual incorporation of cereal straw contributes mainly soil N with a slow turnover.
Conserved chemical properties of young humic acid fractions in tropical lowland soil under intensive irrigated rice cropping
Authors: OLK  , CASSMAN  , MAHIEU  , RANDALL
Published: March 2003

Increasing cropping intensity (i.e. number of crops per year) of irrigated rice seems to cause an accumulation of phenolic compounds in the soil organic matter (SOM). We have studied the chemical nature of SOM in a broad range of soil types at different sites with long‐term double‐ and triple‐crop irrigated rice trials. Accumulation of phenols, as measured by 13C nuclear magnetic resonance spectroscopy, was found in both the mobile humic acid (MHA) and calcium humate (CaHA) fractions at all sites, regardless of soil type, hydrology during the fallow, and with and without inorganic fertilizer or green manures. Although phenols accumulated consistently in MHA and CaHA, the C, N and hydrolysable amino acid concentrations, degree of humification and amounts of MHA and CaHA were significantly altered by crop management, and they varied from site to site. Our results are consistent with the hypothesis that the accumulation of phenols is a characteristic of the anaerobic, or nearly anaerobic, soil conditions that exist at the initial stages of SOM formation in submerged irrigated rice soils. By contrast, other SOM properties are additionally influenced by soil conditions that govern the degradation and turnover of existing SOM. The chemical properties of MHA and CaHA indicated that they are labile, and the quantities of these HA fractions were more sensitive to recent management than were total soil C or N.
Model analysis of the effects of soil age, fires and harvesting on the carbon storage of boreal forest soils
Authors: LISKI J. , ILVESNIEMI H. , MÄKELÄ A. , STARR M.
Published: March 2003

Potential causes for changes in the amounts of carbon (C) stored in the soils of boreal forests were studied by measuring the C in the soil along a 5000‐year chronosequence in coastal western Finland and using a simple dynamic model of decomposition. The amount of soil C stabilized at an age of about 2000 years. This suggests that the youth of many boreal soils does not make them sinks for atmospheric C. Simulated repeated fires kept the amount of soil C reduced by about 25%, but if fires were prevented then the C in the soil increased. Stored C may thus be less than the potential storage where fires are frequent, and it could be increased by preventing fires. Simulated clear‐cutting caused a temporary 5–10% decrease in the amount of soil C over a 20‐year period after the harvesting. It also caused a long‐term decrease in the amount of soil C such that, after two 100‐year rotations, the amount had been decreased by 14%. Stored C is almost certainly less than the potential storage and decreasing where forests are harvested.
Mineral N dynamics in bare and cropped Leucaena leucocephala and Dactyladenia barteri alley cropping systems after the addition of 15N‐labelled leaf residues
Authors: VANLAUWE B. , DIELS J. , DUCHATEAU L. , SANGINGA N. , MERCKX R.
Published: March 2003

In tropical cropping systems with few external inputs, efficient management of mineral N derived from added organic residues is essential for the proper functioning of the system. We studied the dynamics of mineral nitrogen (N) in the top 100 cm of soil with a system of tensiometers and suction cups after applying 15N‐labelled Leucaena leucocephala and Dactyladenia barteri residues to bare and cropped microplots installed in the respective alley cropping systems, and followed the fate of the N for two maize‐cowpea rotations (1992 and 1993).

Fifty days after applying the residues (DDA), 20% of the added residue N was found in the soil profile of the bare Leucaena treatment, and 5% under Dactyladenia, compared with 5% and 1%, respectively, where cropped. All values decreased to about 1% after 505 days. In the cropped soil, no mineral N derived from the residues was lost by leaching during the first 6 weeks.

As the maize grew, the soil profile was gradually depleted of nitrate to near Zero in the Dactyladenia treatment, whereas during the cowpea season the amount of nitrate N increased to 36 kg N ha−1 for the Leucaena treatment, and 26 kg N ha−1 for the Dactyladenia treatment. The soil of the bare microplots contained substantially more nitrate N (98 and 47 kg N ha‐1 during the first year on average, under Leucaena and Dactyladenia, respetively) than that of the cropped microplots, except during the 1993 cowpea season. Nitrate residing in the subsoil (80–100 cm) in the bare treatments was not readily leached to deeper soil. The risk of losses of native mineral N was greatest during the first 50 DAA and to a lesser extent during the cowpea seasons. Improved management of the hedgerows could increase the potential of the hedgerow trees to recycle mineral N.
Modelling soil organic matter changes in ley–arable rotations in sandy soils of Northeast Thailand
Authors: WU J. , O'DONNELL A. G. , SYERS J. K. , ADEY M. A. , VITYAKON P.
Published: March 2003

The effects of a 3‐year ley‐arable rotation (2 years under grass, legume or a grass‐legume mixture, followed by 1 year under cassava) on the organic C content of upland sandy soils in Northeast Thailand were evaluated using four field trials (Khon Kaen, Chaiyaphum, Mahasarakham and Udon Thani). At all sites under the existing management system of continuous cassava, soil organic C decreased by 9‐20% during the 3‐year experiment. The carbon model developed at Rothamsted (RCM‐26) predicted that soil organic C would decrease consistently under continuous cassava until it reached very small amounts (0.2–0.3%). This was the case for all sites, except Chaiyaphum, where soil organic C had already declined to 0.1%. Evaluatin the rotations using RCM‐26 showed that introducing a ley could increase soil organic C, except at Udon Thani where the organic C exceeded 0.47% before the start of the experiment. The data obtained with the rotations showed that RCM‐26 could be used to predict the effects of changes in management on organic C content in the upland sandy soils of Norrtheast Thailand over the 3 years. To compensate for an underestimation of the effects of soil moisture deficit on the decomposition rates of organic matter, we propose that because of the prolonged dry season (from December to the following May) soil moisture deficit and the rate‐modifying factor for moisture (Am) should be estimated independently of crop cover. Furthermore, to accommodate the very slow decomposition during this time, (Am) should be allowed to decrease to 0.1. Adopting this simple modification provides a more realistic estimate of the organic C inputs needed to simulate the content of soil organic C measured before trials began.
A simple equation to describe sorption of anions by goethite
Authors: Barrow N. J.
Published: March 2003

A simple equation to describe sorption of anions by goethite would be useful as a means of characterizing batches of goethite and in studies of plant uptake of anions from the sorbed form. A suitable relationship between solution concentration (c) of phosphate or citrate and their sorption (S) by goethite at a constant pH or at different pH values is

image

where b is a parameter, SMax is the maximum sorption, and a is a parameter at constant pH. In the middle range of sorption (from about 30% to about 70% of maximum sorption) this equation approximated to a Tempkin equation, but the full equation is more useful as it applied over the whole sorption range. The values of a varied with pH. This variation could be explained by changes in the electric potential of the adsorbing surfaces and in the degree of dissociation of the anions. The parameter a could therefore be replaced by a function of pH. The effects were consistent with formation of bidentate phosphate complexes and tridentate citrate complexes with the goethite surface.
A comparison of models for characterizing the distribution of radionuclides with depth in soils
Authors: Smith J. T. , Elder D. G.
Published: March 2003

It is common practice to fit mathematical models to radionuclide activity–depth profiles in soils in order to quantify rates of vertical migration through the soil profile. We have fitted six such models to 21 different activity–depth profiles of radiocaesium (137Cs) derived from Chernobyl and determined relations between the models and the values of their parameters. The advection and dispersion parameters obtained using four solutions to the advection–dispersion equation (each based on different initial and boundary conditions or different simplifications) are in good agreement. We further develop a relation between parameter values obtained using the advection–dispersion models and those determined by a simpler exponential function of the form Aexp(–Bt) where t is the time and A and B are parameters to be estimated. One of the advection–dispersion models proved to be significantly better than the others in terms of goodness‐of‐fit, versatility and ease of use. A simple model, using calculations based on measured characteristics of the activity–depth profile, was shown to accord well with parameters derived from more complex models based on statistical curve fitting. We have also evaluated the ‘residence time’ or ‘compartmental’ model approach to characterizing radionuclide activity–depth profiles. We relate such models to a numerical solution of a simple advection equation, and we show that apparent dispersion in compartmental models is an artefact of numerical dispersion, which can be quantified by the Courant condition. For activity profiles that have a significant advection component, using solutions to the advection–dispersion equation, we have observed a strong positive correlation between advection and dispersion in the profile.
Evaluating soil salinity status from bulk electrical conductivity and permittivity
Authors: Malicki M. A. , Walczak R. T.
Published: March 2003

In the range of volumetric water content, θ, from about 0.12 cm3 cm–3 to saturation the relation between bulk electrical conductivity, Cb, and bulk electrical permittivity, ε, of mineral soils was observed to be linear. The partial derivative ∂Cb/∂ε appeared independent of the moisture content and directly proportional to soil salinity. We found that the variable Xs = ∂Cb/∂ε determined from in situ measurements of Cb(θ > 0.2) and ε(θ > 0.2) can be considered as an index of soil salinity, and we call it the ‘salinity index’. Knowing the index and sand content for a given soil we could calculate the electrical conductivity of the soil water, Cw, which is a widely accepted measure of soil salinity. The two variables from which the salinity index can be calculated, i.e. Cb and ε, can be read simultaneously from the same sensor by time‐domain reflectometry.

Quantities and symbols

a constant /dS m–1

b constant

c constant /dS m–1

C
b electrical conductivity of bulk soil /dS m–1

C
b′ constant equal to 0.08 dS m–1

C
s electrical conductivity of a solution used to moisten soil samples /dS m–1

C
w electrical conductivity of soil water defined as the soil salinity /dS m–1

C
wref reference salinity (that truly existing) resulting from the procedure of moistening samples, expressed as Cs + Cr/dS m–1

C
r baseline value of Cs due to residual soluble salts present in the soil /dS m–1

d constant

D dry soil bulk density /g cm–3

l slope

r ratio

S sand content /% by weight

t time /s

X
s salinity index /dS m–1

X
si initial salinity index when distilled water is used to moisten soil samples /dS m–1

Y a moisture‐independent salinity‐dependent variable /dS m–1

z coordinate along direction of flow of the soil solution

ε′ constant equal to 6.2

ε relative bulk electrical permittivity (dielectric constant) of the soil

θ volumetric water content determined thermogravimetrically using oven‐drying /cm3 cm–3
Changes to hardsetting properties of soil by addition of metal hydroxides
Authors: Breuer J. , Schwertmann U.
Published: March 2003

Hardsetting of soil comprises two contrasting, unfavourable physical conditions at different water contents, namely extreme hardness when dry and complete slaking when wet. This behaviour was changed by adding small amounts of ferrihydrite and aluminium hydroxide to the soil. The aggregation and its stability in the wet state increased, whereas the tensile strength of the dry soils decreased. Both resulted mainly by making the fine particles less mobile by aggregation. In some cases adding large amounts of Al hydroxide caused a resuspension of soil particles by reversing the charge, resulting in instability when wet and high stability when dry. We postulate that aggregation results from the interaction between negatively charged siliceous surfaces and positively charged oxides. In addition we think that newly formed Si–O–Fe bonds play a role in binding particles together as a result of a positive relation between the amount of ferrihydrite added and the oxalate‐soluble Si. We conclude that hardsetting resulting from weak structure is caused by lack of aggregating agents such as metal hydroxides.
Incipient podzolization and weathering caused by complexation in a forest Cambisol on loess as revealed by a soil solution study
Authors: Brahy V. , Titeux H. , Delvaux B.
Published: March 2003

Surface podzolization has so far been diagnosed from morphological observations, selective extraction and mineralogical investigations. We studied this process in two Cambisol profiles developed in loess, one with a fibrimor humus and the other with a dysmoder humus, by characterizing the chemical composition and the complexing properties of the soil solution. The solutions were sampled bimonthly for 3 years at four depths (4, 8, 13, 25 cm) using both zero‐tension and low‐tension capillary‐wick lysimeters. The leachates from the Ah horizon of the soil with fibrimor contained less nitrate, sulphate and calcium than those from the one with a dysmoder because there was less bioturbation and mineralization in it. Both the complexation capacity and the density of ligand binding sites were larger in the soil solutions of the Ah (4 cm) and AB (8 cm) horizons of the soil with the fibrimor. In this soil, the complexing properties of the liquid phase induced a depletion of inorganic monomeric aluminium. In this environment, the hydroxy interlayered 2:1 clay minerals lose their Al‐interlayers and transform into vermiculite and smectite, which in turn weather, producing large amounts of magnesium in the soil solution. This was found to be a major characteristic of weathering by complexation and incipient podzolization in the Cambisol with the fibrimor. In this process, nitric acid probably contributes to mineral dissolution.
Effect of suspended soil material and pig slurry on the facilitated transport of pesticides, phosphate and bromide in sandy soil
Authors: Hesketh N. , Brookes P. C. , Addiscott T. M.
Published: March 2003

The colloid‐facilitated transport of pesticides and other pollutants to groundwaters is a source of concern to authorities in the European Union and other countries. It has been suggested that colloids are good sorbents for pesticides and other pollutants, and it is now suspected that the spreading of animal manures increases the potential for colloid‐facilitated transport. In experiments in lysimeters of sandy soil to which phosphate, triallate, chlordane and bromide were applied to the surface, the first concentration peaks of the other chemicals always appeared before that of bromide, suggesting that their transport was facilitated by colloidal or suspended soil material. Chlordane was transported only when sorbed on suspended soil material and was associated most closely with the coarsest of suspended material (> 1.2 μm), possibly because it contained the most organic matter. Phosphate was also associated with this class but probably because of the clay it contained. Applying pig slurry to the soil significantly increased the loss of triallate from the lysimeters but not that of chlordane, probably because the latter was held strongly by the soil's organic matter. The loss of triallate was not associated with that of any of the size classes of suspended soil material, which may imply that it was transported in association with dissolved or colloidal organic matter. Neither the pig slurry nor an equivalent amount of inorganic phosphate significantly increased the loss of phosphate. The amounts of triallate and chlordane applied were 100 times the standard agricultural applications, but the largest concentration of chlordane measured was still less than the European Union limit of 0.1 μg l−1. That of triallate was greater than the limit but would almost certainly have been less than it with the standard application. The greatest cumulative losses of phosphate, triallate and chlordane were, respectively, 1%, 0.003% and 0.00002% of the amounts applied. All the results suggest there is only a very small pollution risk to groundwaters from the pesticides and phosphate.
Application of cellular and immunological biosensor techniques to assess herbicide toxicity in soils
Authors: Strachan G. , Capel S. , Maciel H. , Porter A.J.R. , Paton G. I.
Published: March 2003

There is growing concern about the fate and toxicity of herbicides to non‐target receptors and an increasing need to measure these analytes sensitively. The responses of cellular and immunological biosensors to four commonly used herbicides (atrazine, diuron, mecoprop and paraquat) were investigated. In combination, these sensors assess toxicity and quantify concentrations of herbicides present in extracts from soil. The bioluminescence response of the lux‐marked bacterial biosensor Escherichia coli HB101 was determined in aqueous extracts from soil to indicate toxicity. Smaller concentrations caused a toxic response for all four herbicides recovered from the Insch series than for those recovered from spiked water samples, but this was not a result of biodegradation of herbicides in the soil. This suggests that intrinsic soil factors may be altering the bioavailable fraction of herbicides, making them more toxic than equivalent concentrations in water.

Herbicide concentrations were determined using immunological biosensors consisting of stabilized recombinant single chain antibodies (stAbs) specific for the four different groups of herbicides. These stAb fragments retain functionality in organic solvents such as methanol commonly used in soil extraction. Anti‐atrazine, mecoprop, diuron and paraquat stAbs were successfully used to identify and quantify herbicides present in aqueous and methanol extracts from soil. The amounts recovered from immunoassay analysis were compared with chemical analysis using high performance liquid chromatography, and the two methods correlated. These stAb fragments might provide a more rapid and sensitive means of quantifying trace amounts of herbicides and their metabolites in aqueous and methanol extracts from soil.
Rate, kinetic energy and momentum of preferential flow estimated from in situ water content measurements
Authors: Germann P. F. , Jäggi E. , Niggli T.
Published: March 2003

Preferential flow needs self‐dependent fluid mechanical characterization and quantification. A theoretical and experimental approach is presented to describe preferential flow with the three variables volume of flowing water and its kinetic energy and momentum. Two soils were irrigated at rates of 50, 75 and 100 mm hour−1 at one site and three times at 100 mm hour−1 at a second site. The variations of soil water content caused by irrigation were measured at five depths with horizontally installed TDR wave guides at 300‐s intervals. The volume flux densities were calculated from the water balances. The computation of momentum and kinetic energy of preferential flow was based on the velocities of the wetting fronts and the amplitudes of the variations of soil water. Kinetic energy per unit volume of flow in the soil exceeds the one of irrigation by factors between 100 and 1000, which indicates concentration of flow. However, kinetic energy per unit volume of flow in the soil is less by factors of 106 to 108 than the capillary potential of soil water. Kinetic energy per unit volume of flow seems a reasonable variable for discriminating between preferential and ordinary flow at a threshold of 2 × 10−6 Pa.
Cadmium leaching from some New Zealand pasture soils
Authors: Gray C. W. , McLaren R. G. , Roberts A. H. C.
Published: March 2003

Cadmium (Cd) inputs and losses from agricultural soils are of great importance because of the potential adverse effects Cd can pose to food quality, soil health and the environment in general. One important pathway for Cd losses from soil systems is by leaching. We investigated loss of Cd from a range of contrasting New Zealand pasture soils that had received Cd predominantly from repeated applications of phosphate fertilizer. Annual leaching losses of Cd ranged between 0.27 and 0.86 g ha–l, which are less than most losses recorded elsewhere. These losses equate to between 5 and 15% of the Cd added to soil through a typical annual application of single superphosphate, which in New Zealand contains on average 280 mg Cd kg−1 P. It appears that Cd added to soil from phosphate fertilizer is fairly immobile and Cd tends to accumulate in the topsoil. The pH of the leachate and the total volume of drainage to some extent control the amount of Cd leached. Additional factors, such as the soil sorption capacity, are also important in controlling Cd movement in these pasture soils. The prediction of the amount of Cd leached using the measured concentrations of Cd in the soil solution and rainfall data resulted in an overestimation of Cd losses. Cadmium concentrations in drainage water are substantially less than the current maximum acceptable value of 3 µg l−1 for drinking water in New Zealand set by the Ministry of Health.
Community‐based management of subsistence fisheries in Samoa
Authors: King M. , Faasili U.
Published: March 2003

Much subsistence fishing in tropical regions is based in discrete communities which have a high level of marine awareness and some degree of control of adjacent waters. These factors provide an ideal basis on which to motivate communities to manage their own marine resources. A fisheries extension programme in Samoa encouraged each village community to define its key problems, discuss causes, propose solutions and take appropriate actions. Various village groups, including women’s and untitled men’s groups, provided information which was recorded (as problem/solution trees) on portable white‐boards. The extension process culminated in a community‐owned Fisheries Management Plan which listed the resource management and conservation undertakings of the community. Undertakings ranged from enforcing laws banning destructive fishing methods to protecting critical marine habitats. Within the first 2 years, the extension process commenced in 65 villages, of which 44 have produced Village Fisheries Management Plans to date. A large number (38) of these villages chose to establish community‐owned Marine Protected Areas.
Attitudes and opinions of commercial fishermen on whitefish management in the Gulf of Bothnia, Finland
Authors: HUHMARNIEMI A. , SALMI J.
Published: March 2003

Abstract  Catches of anadromous whitefish in the Gulf of Bothnia have declined since the early 1990s. It is generally assumed that the cause is overfishing. The professional fishermen interviewed in the present study were united in the opinion that it is necessary to set limits on the fishing of whitefish, but had differing views about the means of achieving this. These different arguments involved separate whitefish stocks, various types of gear and different motives for fishing. Most of the professional fishermen accepted a minimum mesh size for gill nets. Other means proposed included setting limits on non‐professional fishing and sales of catches. There were conflicting attitudes about seasonal restrictions because their experiences with fishing restrictions for salmon had been negative. On the whole, decision‐making requires more regional information on whitefish stocks and fishing, but also on the social and economic flexibility of fishermen.
Yield predictive models for Sri Lankan reservoir fisheries
Authors: Nissanka C. , Amarasinghe U.S. , De Silva S.S.
Published: March 2003

Tropical reservoirs are primarily constructed for irrigation, generation of hydroelectricity and water supply schemes. Development of inland fisheries is a secondary use of most reservoirs. In Sri Lanka, most reservoirs are scattered in the rural areas of the country so that investigation of the fisheries of individual reservoirs with a view to developing management plans is prohibitive. The present study was instigated to explore the possibilities of developing suitable yield predictive models, which can be used in developing management strategies for the Sri Lankan reservoirs. The study was carried out in 11 perennial reservoirs of Sri Lanka. Basic limnological parameters (conductivity, dissolved phosphorus, total phosphorus, chlorophyll a [chl a] content and alkalinity) were determined in each of these reservoirs. Daily data on fish catch and fishing effort were collected in each reservoir. Data on catchment areas (CA), reservoir area (RA) and reservoir capacity (RC) were obtained from the irrigation and survey departments. It is evident that chl a is positively influenced by nutrients (dissolved phosphorus and total phosphorus), morphoedaphic indices derived as alkalinity to mean depth (MEIa) and conductivity to mean depth (MEIc) ratios and CA/RC ratios. MEIa and MEIc are also positively influenced by CA/RC ratios. All these morphological and edaphic parameters were found to positively influence fish yield in reservoirs. As fishing intensity (FI) is also a major determinant of fish yields, fish yield was better accounted by multiple regression models in which FI and individual morphological and edaphic parameters were used as independent variables. Of these multiple regression relationships, the best predictive power for fish yield (Y in kg ha−1 yr−1) was found by Y=18.9+6.78 FI+0.0073 CA/RC where FI is expressed as boat‐days ha−1 yr−1 and CA and RC are in km2 and km3, respectively. In this relationship, FI and CA/RC account for about 68% of the variation in fish yield.
Diel drift behaviour of fish eggs and larvae, in particular barbel, Barbus barbus (L.), in an English chalk stream
Authors: COPP G. H. , FAULKNER H. , DOHERTY S. , WATKINS M. S. , MAJECKI J.
Published: March 2003

To estimate the potential loss of fish larvae to downstream stretches, the downstream drift behaviour of fish eggs and larvae, in particular barbel, Barbus barbus (L.), was examined in the River Lee, a small, nutrient‐rich chalk stream in England, using drift nets over nine consecutive 24‐h periods in June 1993 at one location and over ten 24‐h periods, once a week for 10 weeks from May to July 1995 at a location slightly more upstream. The density of drifting fish larvae was not correlated with river discharge in 1993 or 1995. A clear diel pattern was found in the drift of fish eggs and larvae, with barbel being a predominant species. Almost all fish larvae drifted at night both in 1993 and 1995, but the drift of eggs in 1995 occurred regardless of luminosity, although most eggs drifted during the day and at dawn. The highest densities of drifting fish larvae (in particular barbel) were found in the nets set in the highest water velocities, with the opposite pattern observed for fish eggs, suggesting either active response to the water current or shape‐related differences in the drift behaviour of passive particles.
Larval feeding behaviour of the endangered fish golden bubblebee goodeid, Allotoca dugesi, implications for conservation of an endangered species
Authors: DOMÍNGUEZ‐DOMÍNGUEZ O. , NANDINI S. , SARMA S. S. S.
Published: March 2003

Abstract To improve survival of cultured juvenile fishes, it is important to understand prey preferences and predation behaviour of fish larvae. In this study, the feeding behaviour and prey preference of Allotoca dugesi (Bean), a small fish species endemic to Mexico and currently threatened with extinction are presented. Three zooplanktonic prey, viz. Brachionus calyciflorus (Pallas), Moina macrocopa (Goulden) and Daphnia pulex (Leydig) were tested. The mean size (standard length ± SE, mm) of the larvae ranged from 9.0 ± 0.1 mm at week 1 to 18 ± 2 mm at the end of the experimental period (8 weeks). The gape size (mean ± SE) increased from 0.125 ± 0.002 mm at the first week to 2.300 ± 0.361 mm by the eighth week. Capture success (capture/attack) ranged from 0.80 to 0.98 with Brachionus, 0.72–0.94 with Moina and 0.17–0.46 with Daphnia. Prey preference experiments were conducted using B. calyciflorus, M. macrocopa and D. pulex at a fixed ratio of 5 : 2 : 2 ind. mL−1, respectively, and revealed a positive selection for rotifers and Moina, but avoidance of Daphnia. The results are discussed with reference to conservation efforts for Allotoca dugesi.