bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of seven new TCRBV subfamilies in cattle (Bos taurus)*
Authors: Houston E. F. , Morrison W. I. 
Published: March 2003

AbstractIn cattle, the repertoire of TCRBV genes that encode the variable region of T‐cell receptor β‐chains has not been fully characterized. In this study, cattle TCRBV genes were amplified from mRNA by anchored polymerase chain reaction and sequenced. Eleven new TCRBV gene sequences were found, and classified into seven subfamilies distinct from those previously identified.
Analysis of deletions in three McLeod patients: exclusion of the XS locus from the Xp21.1–Xp21.2 region
Authors: Nemer Wassim El , Colin Yves , Collec Emmanuel , Gane Pierre , Cartron Jean Pierre , Le Van Kim Caroline 
Published: March 2003

AbstractThe McLeod syndrome is a rare X‐linked recessive disorder characterized by blood group, neuromuscular and haematopoietic abnormalities. It is caused by XK gene defects and may include large deletions in the Xp21 region. Analysis of three unrelated McLeod patients for the presence of the XK, DMD, CYBB, ETX1, RPGR and OTC loci, as well as for the DXS709 marker, revealed deletions from the 39th exon of DMD to the ETX1 locus (patient Be), from the XK to RPGR loci (patient Bi) and from the XK to CYBB loci (patient Lh). All three patients normally expressed the Lutheran (Lu) red cell antigens, thus excluding the interval between the RPGR and DMD genes as site of the XS locus, previously mapped to the Xp21.2–Xq21.1 region and thought to regulate the expression of the LU blood group gene on chromosome 19.
CTLA4 exon 1 dimorphism in bullous and cicatricial pemphigoid
Authors: Drouet M. , Aupetit C. , Delpuget‐Bertin N. , Bedane C. , Bonnetblanc J. M. , Cogné M. 
Published: March 2003

AbstractThe human cytotoxic T‐lymphocyte antigen 4 (CTLA4) gene encodes proteins regulating the immune response. The polymorphism of this gene is associated with some autoimmune diseases. In this study, we analysed the distribution of the dimorphisms of exon 1 (+ 49 A/G) in bullous pemphigoid (BP) and cicatricial pemphigoid (CP), two types of autoimmune bullous skin diseases that occur in elderly people. The frequency of the exon 1 A‐G genotype was marginally decreased in patients (36.4%; n = 55) compared with controls (52.8%, n = 53), but the results were not statistically significant (P = 0.09).
HLA antigen and gene frequencies in Eskimos of East Greenland
Authors: Welinder L. , Graugaard B. , Madsen† M. 
Published: March 2003

AbstractA population of 78 Ammassallik Eskimos was tested for HLA‐A, B, Cw, DR and DQ specificities using serological techniques and HLA‐Cw, DRB, DQB1 and DPB1 using three different genomic techniques. The application of two new genomic techniques for HLA‐Cw (PCR‐SSP phototyping) and HLA‐DPB1 (PCR‐RLFP) typing confirmed serological results and gave a higher resolution, with more heterozygotes than previously found. High gene frequencies of HLA‐A24 (0.80), B51 (0.21), B61 (0.30), B62 (0.21), Cw*0303 (0.27), Cw*0304 (0.51), DRB1*0401 (0.45), DRB1*1402 (0.24), DQ7 (0.88), DPB1*0201 (0.18), DPB1*0401 (0.40) and DPB1*0402 (0.30) were found. A limited number of alleles were found at all HLA loci. The Ammassallik Eskimos of East Greenland are genetically homogenous with little, if any, admixture with European populations. This contrasts with other Greenlandic populations formerly tested. The pattern of alleles indicates a close genetic relationship with other Eskimo populations.
The genomic organization of the mouse CD94 C‐type lectin gene
Authors: Lohwasser S. , Wilhelm B. , Mager D. L. , Takei F. 
Published: March 2003

AbstractThe mouse natural killer (NK) gene complex is located on chromosome 6 and contains a number of genes encoding C‐type lectin receptors which have been found to regulate NK cell function. Among these are CD94 and four NKG2 genes. Like its human counterpart, the mouse CD94 protein associates with different NKG2 isoforms and recognizes the atypical MHC class I molecule Qa‐1b. Here, the genomic organization of the mouse CD94 gene was determined by analysing a BAC clone containing the CD94 gene. The mouse CD94 gene contains six exons separated by five introns. Exons I and II encode the 5′ untranslated region (UTR) and the transmembrane domain. Exon III encodes the stalk region and exons IV–VI encode the carbohydrate recognition domain (CRD). Furthermore, we cloned and sequenced the CD94 promoter region, and putative regulatory DNA elements were identified. Further studies on the CD94 promoter region may help to elucidate the restricted expression pattern of CD94 in NK cells and a subpopulation of T cells.
Lymphocyte antigens in sheep: linkage to the MHC class II DRB1 gene
Authors: Jugo B. M. , Vicario A. 
Published: March 2003

SummaryIn this work a typing battery of sera was developed to test lymphocyte antigens in sheep. Eight antigens were detected in a Latxa sheep sample. The serological determination of these antigens is described. As some of the detected antigens segregated in close linkage with class II DRB1 SSCP patterns in two half‐sib families, we can conclude that they are coded by genes located in the MHC. Gene frequencies were very similar in Latxa Mutur Gorria and Latxa Mutur Beltza, the two varieties of the Latxa breed. Although few animals were typed in the comparison with other typing sera, it seems that two of our sera clusters detect the same antigens as those detected by other research groups working in other breeds with their own typing batteries.
Characterization of Peromyscus MHC class II beta sequences by ligation‐anchored RT‐PCR and denaturing gradient gel electrophoresis
Authors: Richman A. D. , Herrera L. G. , Nash D. 
Published: March 2003

SummaryWe characterized MHC class II beta sequences in deermice (genus Peromyscus), which are amongst the most common mammals in North America. We find evidence for two different families of class II beta loci, most closely related to either the A‐type or E‐type loci in Mus. Population studies suggest the presence of more than one A‐type locus but only one E‐type locus for the species investigated.
Recombinant DRB sequences produced by mismatch repair of heteroduplexes during cloning in Escherichia coli
Authors: Longeri M. , Zanotti M. , Damiani G. 
Published: March 2003

SummaryRecombinant chimeric sequences originating from a mixture of the sequences of two different alleles are frequently found after amplification and cloning in Escherichia coli of exon 2 of the major histocompatibility complex (MHC) DRB genes. Several authors have suggested that the recombinant molecules result from in vitro recombination during PCR; nevertheless, a clear experimental demonstration of this hypothesis is lacking. In order to understand the mechanism producing the chimeric sequences, we set up a simple experiment based on the different restriction patterns of parental and recombinant sequences. Our data demonstrate that in the analysed case most of the recombinant variants were not produced by in vitro recombination during PCR, but were the result of the mismatch repair of heteroduplex molecules during cloning in E. coli. The high mutation rate in the α‐helix region of DRB expressed genes, both after cloning in E. coli and after the germ‐line differentiation process in vertebrates, suggests that the observed mutations are the result of similar gene conversion processes, probably favoured by chi‐dependent microrecombination events.
Extractability and dissolution kinetics of pure and soil‐added synthesized aluminium hydroxy sulphate minerals
Authors: PRIETZEL J. , HIRSCH C. 
Published: March 2003

SummaryVarious extractants used in current analytical procedures for the fractionation of sulphur (S) in soils were compared with respect to their ability to dissolve Al hydroxy sulphate minerals of defined composition (basaluminite, K alunite, mixtures of basaluminite and Na alunite). The minerals were synthesized and aged in the laboratory at 20°C and 50°C. The dissolution kinetics at 20°C of these Al hydroxy sulphates in deionized water, 0.02M HCl and 0.02M NaOH were also investigated.The dissolution stability of the Al hydroxy sulphate minerals increased in the order basaluminite < K alunite < Na alunite. The dissolving power of the reagents used increased in the order H2O ≤ 0.016M KH2PO4≪ 0.02M HCl ≈ acidic NH4 oxalate ≈ 0.5M NaHCO3 < Na2 CO3/NaHCO3 < 0.1M NH4F < 0.5M NH4F < 0.05M NaOH ≤ 0.05M LiOH. In Al hydroxy sulphate‐containing soils, inorganic S is probably understimated and ester sulphate S overestimated, if the inorganic S pool is assessed by extraction with KH2PO4, Ca(H2PO4)2 or NaHCO3 solutions. The dissolution of all studied Al hydroxy sulphates, particularly that of K and Na alunite, in H2O and 0.02 M HCl is strongly delayed by kinetic restraints. Thus it seems unlikely that Al3+ or SO2−4 activites in soil solutions are strictly regulated by precipitation/dissolution equilibria of these minerals except for horizons with extraordinarily slow seepage water movement.
Influence of the nature of clay minerals on the fixation of radiocaesium traces in an acid brown earth–podzol weathering sequence
Authors: Maes E. , Iserentant A. , Herbauts J. , Delvaux B. 
Published: March 2003

SummaryThe magnitude of radiocaesium fixation by micaceous clay minerals is affected by their transformation, which depends on weathering in soil. The net retention of radiocaesium traces was quantified by sorption–desorption experiments in the various horizons of four sandy soils forming an acid brown earth–podzol weathering sequence derived from sandy sediments and characterized by marked changes in mineral composition. The features of the 2:1 minerals of the four soils, resulting from an aluminization process in depth and a desaluminization process towards the surface, had a strong influence on Cs+fixation. Beneath the desaluminization front, which deepens from the acid brown earth to the podzol, hydroxy interlayered vermiculite was dominant and the137Cs+fixation was the weakest. At the desaluminization front depth, vermiculite was responsible for the strongest137Cs+fixation. In the upper layers, smectite appeared in the podzolized soils and the137Cs+fixation decreased. The magnitude in Cs+fixation therefore appeared as a tracer of the transformation process affecting the 2:1 clay minerals in the acid brown earth–podzol weathering sequence. This magnitude was positively correlated with the vermiculite content of the studied soil materials estimated by the rubidium saturation method.
Molecular characteristics related to the biodegradability of humic acid preparations
Authors: Almendros G. , Dorado J. 
Published: March 2003

SummaryThe resistance of soil humic material in soil seems to depend on its molecular characteristics. We have studied 12 chemically modified humic samples in mineral soil to identify molecular characteristics connected with their resistance to biodegradation. The treatments, used to introduce changes in the composition, reactivity and N content of the original humic acid (HA), consisted of acetylation, amidation, methylation, nitration, oximation, sulfonation, acid and alkaline hydrolysis, hydrogen peroxide oxidation and fixation of ammonia and of stearic acid. The relations between respirometric data (total mineralization coefficient and mineralization rates at different stages of the 85‐day mineralization curve) and a series of HA characteristics (wet chemical analyses, spectroscopic data and relative yields of different pyrolysis products) were examined by correlation and by multiple regression models.The structural characters of HA most directly related to the susceptibility to biodegradation were the concentration of O–alkyl structures and oxygen content mainly in phenolic structures. The aliphatic/aromatic ratio showed no significant correlation with the resistance of organic matter. The fact that the yields of lignin‐derived pyrolysis compounds were directly related to carbon mineralization suggested that the structural contribution of domains consisting of preserved biomacromolecules is more important than the neat aromaticity of the HA.The multiple regression models suggested that molecular size of the HA had the greatest influence in the early mineralization stages, whereas the characteristics of the C backbone (concentration of O–alkyl and alkyl carbons) had a greater influence in the advanced transformation stages in the soil.The lack of significant correlations with N concentration indicated that native N forms as well as N‐containing groups introduced in peat HA did not have a measurable trophic effect on the biodegradation. The disordered macromolecular structure of the HAs seems to play a greater role in their resistance to biodegradation than the relative amounts of their major structural constituents.
Effect of water tension on ethylene production and consumption in montane and lowland soils in Austria
Authors: Zechmeister‐Boltenstern S. , Nikodim L. 
Published: March 2003

SummaryThe trace gas ethylene affects plant growth and atmospheric chemistry and it interferes with soil restoration. In soil ethylene is simultaneously produced and consumed by different microorganisms. The effects of land use and soil moisture conditions on processes leading to an accumulation of ethylene are still unclear. We measured the rates at which montane and lowland soils from Austria produced and consumed ethylene over a range of water tensions and oxygen supply. Complete anaerobiosis (waterlogging, zero tension) favoured ethylene production, whereas ethylene degradation rates were greatest in soils at 30 kPa water tension. Soils from the lowland region of eastern Austria produced ethylene at rates of up to 12 pmol C2H4g–1 h–1under anaerobic conditions, and they consumed ethylene at rates reaching 231 pmol C2H4g–1 h–1, after addition of 20 μl l–1ethylene. Deciduous forest soils consumed ethylene fastest. Ethylene formed rapidly and was also consumed rapidly in soils rich in humus and total nitrogen. Soils taken from the mountains both produced and consumed ethylene more rapidly than lowland soils did. Production rates reached 146 pmol C2H4g–1 h–1under anaerobic conditions. Spruce forest soils produced significantly more ethylene than pastures. Ethylene formation was negatively correlated with soil pH. In montane soils ethylene production was related to the availability of simple carbon sources, expressed by the amount of extractable glucose equivalents. Maximum ethylene degradation amounted to 895 pmol g–1 h–1. Most of the soils were net sinks for ethylene at a water tension of 30 kPa and drier.
Water‐soluble organic matter in incipient podzols: accumulation in B horizons or in fibres?
Authors: Nierop K. G. J. , Buurman P. 
Published: March 2003

SummaryTo elucidate the mechanism of podzolization in its first stages we studied the fate of the water‐soluble organic matter (WSOM) in incipient podzols in sandy soils by comparing the composition of the WSOM from L, F and H horizons with that in the bulk of the Bh horizons and fibres of three profiles. The WSOM appeared to consist significantly of ligno‐cellulose and proteins, but these biopolymers were hardly present in the Bh horizons. The material of the fibres, however, greatly resembled the WSOM composition, thereby suggesting that in these soils most of the WSOM is transported through the B horizon and accumulates hardly changed in thin bands where the water stops moving. This implies that in the early steps of podzolization, accumulation of organic matter in the B horizon is not likely to be caused by water‐soluble material.
Decalcification of soils subject to periodic waterlogging
Authors: Van Den Berg G. A. , Loch J. P. G. 
Published: March 2003

SummaryIntense decalcification of fine‐grained organic‐rich soils subject to periodic oxidation and reduction takes place in the Biesbosch, a freshwater, tidally influenced wetland area in the Rhine–Meuse delta in The Netherlands. Soil chemical (sulphide concentration and pore‐water characteristics) and hydrological variables (drainage) were measured in three representative Fluvisols differing in hydrology to identify processes inducing calcium carbonate dissolution. Both oxidation of previously formed iron sulphides during periods of low ground water and infrequent inundation, and increased carbon dioxide pressure in the soil during periods of waterlogging combined with drainage of pore‐water solutes, contribute significantly to decalcification of the hydric soils. The effects of these individual processes on decalcification are in the same order of magnitude in the studied soils. Depending on site‐specific hydrological conditions, approximately 0.1–0.3% calcium carbonate may be dissolved per year by a combination of these two processes, which is comparable to actual decalcification rates at these sites. Estimates of long‐term decalcification rates, based on knowledge of the hydrogeochemistry, may be used to assess the risks accompanying the conversion of agricultural soils into wetlands.
Estimation of soil weathering stage and acid neutralizing capacity in a toposequence Luvisol–Cambisol on loess under deciduous forest in Belgium
Authors: Brahy V. , Deckers J. , Delvaux B. 
Published: March 2003

SummarySoils derived from loess are extensive in Europe and are well suited for forestry. They are suspected to be poor acid buffers, however. We have estimated the weathering stage and acid neutralizing capacity of acid soils under forest in a toposequence on loess in the Belgian silt belt. The soils vary distinctly in morphology and physico‐chemical properties according to their topographic position. Dystric Cambisols have developed in colluvial deposits in the dry valley floors, whereas Dystric Luvisols have formed on the slopes in a rejuvenated material. The Cambisols are more acid and less saturated in bases than are Luvisols. They are strongly depleted of clay and contain less weatherable minerals. Easily weatherable minerals are concentrated mainly in the clay fraction of both soil types. Clay minerals of size < 2 μm therefore act as major sinks for protons in these soils. A simplified expression taking into account the total reserve in bases, total aluminium and iron occluded in silicates is used to estimate acid neutralizing capacity. Our estimates confirm that these acid loessic soils are indeed poor acid buffers. They show that the Dystric Cambisols depleted of clay are sensitive to potential acidification, whether natural or man‐made.
A cation exchange index for assessing degradation of acid soil by further acidification under permanent agriculture in the tropics
Authors: Noble A. D. , Gillman G. P. , Ruaysoongnern S. 
Published: March 2003

SummarySoil acidification and related land degradation are becoming more important worldwide and are challenging the concept of sustainability of current land management systems. We have studied the impact on soil properties of two management systems, one in a tropical savanna, the other in a humid subtropical environment, particularly in relation to their cation chemistry. In Northeast Thailand the properties of an Acrisol cleared of dipterocarp forest some 37 years previously and used for continuous crop production are compared with adjacent undisturbed forest. In southern Queensland, Australia, the properties of a Luvisol used for intensive pasture production for 36 years are compared with those prior to introduction of the management system. Under both regimes, the soil pH fell by about 1 unit, with an increase in aluminium saturation of the cation exchange complex. Organic carbon in the Acrisol greatly decreased, but in the Luvisol it increased significantly. Consequently, the effects on surface charge characteristics were strikingly different, in that the Acrisol had been almost irreversibly degraded, whereas acidification and base diminution in the Luvisol can be easily reversed through conventional management. The amount of degradation caused by each management system has been quantified in terms of a Saturation Index, Su: S
u = 100 × (Cu5.5 − Σ)/Cu5.5,where Cu5.5 refers to the cation exchange capacity on the undisturbed (forested) site and Σ is the sum of the base cations at field pH. This index encompasses an assessment of the degree of degradation taking into account the previous land use, in this case forest, and that due to anthropogenic disturbance. For the Queensland Luvisol Su does not change, because the pasture management has not appreciably altered the CEC at pH 5.5. However, for the Thailand site Su increased from 0 to 86%. Consequently in its present state, the surface horizon of this cultivated soil can retain only about 15% of the basic cations it could ideally hold under undisturbed conditions.
A mono‐component model of carbon mineralization with a dynamic rate constant
Authors: Yang H. S. , Janssen B. H. 
Published: March 2003

SummaryThe difficulties in using complicated models of carbon mineralization and the poor performance of simple ones call for new models that are simple in use and robust in performance. We have developed a model for the mineralization of carbon from experimental data in which the organic matter is treated as a single component. The logarithm of the average relative mineralization rate, K, or rate constant, of a substrate considered as a whole was found to be linearly related to the logarithm of time, t, provided prevailing soil conditions remained unchanged. The equation is: logK = logR–S logt, or K = R t–S, in which R (dimension tS − 1) represents K at t = 1, and S (dimensionless, 1 ≥ S≥ 0) is a measure of the rate at which K decreases over time, also called the speed of ‘ageing’ of the substrate. The quantity of the remaining substrate, Yt, is calculated by Yt = Y0 exp(–Rt1 – S), where Y0 is the initial quantity of the substrate. The actual relative mineralization rate, k, at time t is proportional to K, according to k = (1 − S)K. The model was tested against an assembly of 136 sets of data collected from trials conducted in 14 countries all over the world. They cover materials ranging from glucose, cellulose and plant residues, to farmyard manure, peat and soil organic matter. The results lead to the conclusion that the model describes well the dynamics of organic matter in soil over time varying from months to tens of years, provided major environmental conditions remain unchanged. It can easily be applied in practice and is attractive because of its modest input requirements.
Field‐scale run‐off and erosion in relation to topsoil aggregate stability in three tropical regions (Benin, Cameroon, Mexico)
Authors: Barthès B. , Azontonde A. , Boli B. Z. , Prat C. , Roose E. 
Published: March 2003

SummaryThe influence of aggregate stability on run‐off and erosion has often been reported from experiments on microplots (about 1 m2) under simulated rain. Our objective was to compare the aggregate stability of topsoil (0–10 cm) with run‐off and erosion from experiments on run‐off plots (about 100–1000 m2) under natural rain. Run‐off and soil losses were measured over three years on 14 plots in Benin, Cameroon and Mexico. All plots were under herbaceous vegetation and had moderate slope length and slope declivity, but differed in climate (400–1600 mm annual rainfall), soil type (sandy clay loam Nitosol, loamy sand Ferralsol, loamy Regosol), and management (from savanna to long‐duration mouldboard ploughing). The stability of aggregates was determined by immersing and wet‐sieving 2‐mm sieved air‐dried samples into water.Mean annual run‐off rate and soil losses generally increased, and the proportion of stable macroaggregates (> 0.2 mm) decreased, with increasing duration and intensity of tillage, and with decreasing cover on the soil surface. For all 14 plots, run‐off and soil losses were closely correlated with aggregate stability; correlations were improved when slope gradient and climate aggressivity were considered in addition to aggregation. Slaking, the main mechanism of aggregate breakdown which occurs when dry soil is immersed, accounted well for run‐off and erosion. The stability of topsoil aggregates seems therefore to be a valuable indicator of field‐assessed run‐off and erosion for plots on moderate slopes with herbaceous vegetation.