The capacity of soils to preserve organic C and N by their association with clay and silt particles

Although it has been recognized that the adsorption of organics to clay and silt particles is an important determinant of the stability of organic matter in soils, no attempts have been made to quantify the amounts of C and N that can be preserved in this way in different soils. Our hypothesis is that the amounts of C and N that can be associated with clay and silt particles is limited. This study quantifies the relationships between soil texture and the maximum amounts of C and N that can be preserved in the soil by their association with clay and silt particles. To estimate the maximum amounts of C and N that can be associated with clay and silt particles we compared the amounts of clay- and silt-associated C and N in Dutch grassland soils with corresponding Dutch arable soils. Secondly, we compared the amounts of clay- and silt-associated C and N in the Dutch soils with clay and silt-associated C and N in uncultivated soils of temperate and tropical regions.We observed that although the Dutch arable soils contained less C and N than the corresponding grassland soils, the amounts of C and N associated with clay and silt particles was the same indicating that the amounts of C and N that can become associated with this fraction had reached a maximum. We also observed close positive relationships between the proportion of primary particles < 20 m in a soil and the amounts of C and N that were associated with this fraction in the top 10 cm of soils from both temperate and tropical regions. The observed relationships were assumed to estimate the capacity of a soil to preserve C and N by their association with clay and silt particles. The observed relationships did not seem to be affected by the dominant type of clay mineral. The only exception were Australian soils, which had on average more than two times lower amounts of C and N associated with clay and silt particles than other soils. This was probably due to the combination of low precipitation and high temperature leading to low inputs of organic C and N.The amount of C and N in the fraction > 20 m was not correlated with soil texture. Cultivation decreased the amount of C and N in the fraction > 20 m to a greater extent than in the fraction < 20 m, indicating that C and N associated with the fraction < 20 m is better protected against decomposition.The finding of a given soil having a maximum capacity to preserve organic C and N will improve our estimations of the amounts of C and N that can become stabilized in soils. It has important consequences for the contribution of different soils to serve as a sink or source for C and N in the long term.     

DNA polymorphism haplotypes of the human lipoprotein lipase gene: possible association with high density lipoprotein levels

Summary Lipoprotein lipase (LPL) plays a central role in the metabolism of lipoproteins by hydrolyzing the core triglycerides of circulating very low density lipoproteins and chylomicrons. The enzyme is encoded by a gene about 30kb in size located on the short arm of human chromosome 8. We have determined the locations of the four common DNA polymorphisms along the gene, including a polymorphism that occurred only among an American black population examined. These restriction site polymorphisms were used for haplotype analysis of Mediterranean and US black families. Estimation of the extent of nonrandom association between these polymorphisms indicated considerable linkage disequilibrium between these sites. No correlation was observed between the level of linkage disequilibrium and the physical distance of the polymorphic sites. The polymorphism information content of the haplotypes ranged from 0.65 to 0.74, thereby constituting a relatively useful genetic marker on chromosome 8. We tested for possible associations between the polymorphisms and circulating lipoprotein phenotypes in a population of 139 Caucasians undergoing coronary arteriography and 50 of their spouses. Some possibly significant associations between LPL gene polymorphisms and levels of high density lipoprotein cholesterol (P = 0.015) and total plasma cholesterol (P = 0.025) were observed. In contrast to a previous report, we found no significant associations with the levels of plasma triglycerides.     

Cytokines and their association with insulin resistance in obese pregnant women with different levels of physical activity

BackgroundCytokines contribute to insulin resistance in pregnancy, but the role of distinct cytokines is not fully understood.ObjectivesTo study whether cytokines produced by tissues other than skeletal muscle are associated with glucose and insulin metabolism activity in overweight and obese women and to study whether these associations can be modified by physical activity.MethodsA longitudinal study with 44 overweight and obese pregnant women was conducted. Changes in cytokines levels (IFN-γ, IP-10, IL1-α, MIP1-α, adiponectin and leptin) and ICAM1 from early (15 wk) to late (32 wk) pregnancy were determined. Physical activity was measured objectively with accelerometers. In linear regression models, the associations between (changes in) cytokine levels and fasting glucose, fasting insulin and HOMA-IR were studied.ResultsBoth IFN-γ and IP-10 levels increased from early to late pregnancy, and adiponectin levels decreased. IFN-γ and IP-10 were positively associated with fasting glucose, whereas IL-1α, ICAM1 and adiponectin were inversely associated with insulin and insulin resistance. The association of IL-1α with insulin and insulin resistance was only found in women with low levels of physical activity.ConclusionsIFN-γ, IP-10, IL1-α, ICAM1, and adiponectin may play a role in glucose and insulin metabolism in pregnancy. The relationship of IL-1α with insulin and insulin resistance might be moderated by levels of physical activity. Further studies are required to confirm the role of these cytokines in glucose and insulin metabolism in obese pregnant women.     

Differential expression of porcine sperm microRNAs and their association with sperm morphology and motility

MicroRNAs (miRNAs) are involved in nearly every biological process examined to date, but little is known of the identity or function of miRNA in sperm cells or their potential involvement in spermatogenesis. The objective was to identify differences in miRNA expression between normal porcine sperm samples and those exhibiting high percentages of morphological abnormalities or low motility. Quantitative RT-PCR was performed on sperm RNA to compare expression levels of 10 specific miRNAs that are predicted to target genes that code for proteins involved in spermatogenesis, sperm structure, motility, or metabolism. There were increases in the expression of four miRNAs, let-7a, -7d, -7e, and miR-22, in the abnormal group (P < 0.05), whereas miR-15b was decreased compared to controls (P < 0.05). Two miRNAs, let-7d and let-7e, were increased in the low motility group when compared to controls (P < 0.05). Bioinformatic analyses revealed that messenger RNA targets of the differentially expressed miRNAs encode proteins previously described to play roles in sperm function. Although the precise role of miRNA in sperm remains to be determined, their changes as associated with morphology and motility signify a critical biological function. Perhaps they are remnants of spermatogenesis, stored for a later role in fertilization, or are delivered to the oocyte to influence early embryonic development. Although there is no single cause of male infertility, the identification of miRNAs associated with sperm motility, structural integrity, or metabolism could lead to the development of a microarray or real time-based diagnostic assay to provide an assessment of male fertility status.     

DR antigen expression on ovarian carcinoma cells does not correlate with their capacity to elicit an autologous proliferative response

Summary Expression of HLA-DR antigens by purified preparations of human ovarian carcinoma cells freshly isolated from surgical specimens was examined in parallel with the capacity of tumor cells to elicit a blastogenic response from autologous lymphocytes in mixed lymphocyte-tumor culture (MLTC) assay. Of 21 tumor preparations, 11 (52%) reacted with monoclonal antibodies 279 and/or 949 specific for a monomorphic determinant of HLA-DR antigens, with heterogeneous positivity, ranging between 30% and 95%. In this series of patients positive MLTC occurred in 8/21 individual experiments. The HLA-DR expression was proportionally similar in tumors giving positive MLTC (4/8=50%) and negative MLTC (7/13=53%). The lack of correlation between DR expression on tumor cells and stimulatory activity in autologous MLTC and the fact that DR-negative tumors could induce lymphocyte stimulation, support the hypothesis that blastogenesis occurs upon recognition of tumor-associated antigens, different from DR molecules, possibly tumor-specific antigens.     

Subjective and objective levels of physical activity and their association with cardiorespiratory fitness in rheumatoid arthritis patients

IntroductionThe aims of the present study were: (a) to examine the agreement between subjective (assessed via the International Physical Activity Questionnaire; IPAQ) and objective (accelerometry; GT3X) physical activity (PA) levels in patients with rheumatoid arthritis (RA), and (b) to evaluate the associations of RA patients’ subjective and objective PA to their scores on the maximal oxygen uptake test (VO2max).MethodsThe participants wore the GT3X for seven days before completing the IPAQ and VO2max test. The Bland-Altman plot was used to illustrate the agreement between the objective and subjective PA data, and the Wilcoxon test was employed to examine the differences. The association between the PA measurement and VO2max test was examined via the correlations and the magnitude was presented by the Steiger’s Z value.ResultsSixty-eight RA patients (age = 55 ± 13 years, body mass index: 27.8 ± 5.4 kg/m2, median of disease duration = 5 (2–8) yrs) were recruited. Smaller differences between the subjective and objective measures were found when PA was assessed at the moderate level. Wilcoxon tests revealed that patients reported less time spent engaged in sedentary behaviours (Z = −6.80, P < 0.01) and light PA (Z = −6.89, P < 0.01) and more moderate PA (Z = −6.26, P < 0.01) than was objectively indicated. Significant positive correlations were revealed between VO2max with all PA levels derived from accelerometry (light PA rho = .35, P < .01; moderate PA rho = .34, P = .01; moderate and vigorous PA, (MVPA) rho = .33, P = .01), and a negative association to sedentary time (ST) emerged (rho = −.27, P = .04). IPAQ-reported moderate PA and MVPA positively correlated with maxV02 (rho = .25, P = .01, rho = .27, P = .01, respectively). Differences between the magnitude of correlations between the IPAQ-VO2 max and GT3X-VO2 max were only significant for ST (Z = 3.43, P < .01).ConclusionsVia responses to the IPAQ, RA patients reported that they were less sedentary and engaged in more higher intensity PA than what was objectively assessed. Accelerometry data correlated with VO2max at all PA levels. Only subjective moderate and MPVA correlated with VO2max. Findings suggest that self-reported PA and ST should be interpreted with caution in people with RA and complemented with accelerometry when possible.

Trial registration

Trial registration: ClinicalTrials.gov ISRCTN04121489. Registered 5 September 2012.     

Arabidopsis thaliana leaf form evolved via loss of KNOX expression in leaves in association with a selective sweep

Morphological diversity is often caused by altered gene expression of key developmental regulators. However, the precise developmental trajectories through which morphologies evolved remain poorly understood. It is also unclear to what degree genetic changes contributing to morphological divergence were fixed by natural selection. Here we investigate these problems in the context of evolutionary developmental transitions that produced the simple unlobed leaf of the model species Arabidopsis thaliana. We demonstrate that A. thaliana leaf shape likely derived from a more complex lobed ancestral state that persists in extant Arabidopsis species. We also show that evolution of the unlobed leaf form in A. thaliana involved loss of expression of the knotted1-like homeobox gene SHOOTMERISTEMLESS (STM) in leaves and that cis-regulatory divergence contributed to this process. Further, we provide evidence for a selective sweep at the A. thaliana STM locus, indicating that loss of STM expression in A. thaliana leaves may have been fixed by positive selection. In summary, our data provide key information as to when and how the characteristic leaf form of A. thaliana evolved.     

Significant association of interleukin-4 gene intron 3 VNTR polymorphism with susceptibility to knee osteoarthritis

Objective

Interleukin-4 (IL-4) is a strong chondroprotective cytokine and polymorphisms within this gene may be a risk factor for osteoarthritis (OA). We aimed to investigate genotype and allele frequencies of IL-4 gene intron 3 variable number of tandem repeats (VNTR) polymorphism in patients with knee OA in a Turkish population.

Methods

The study included 202 patients with knee OA and 180 healthy controls. Genomic DNA was isolated and IL-4 gene 70 bp VNTR polymorphism determined by using polymerase chain reaction (PCR) with specific primers followed by restriction fragment length polymorphism (RFLP) analysis.

Results

Our result show that there was statistically significant difference between knee OA patients and control group with respect to IL-4 genotype distribution and allele frequencies (p = 0.000, OR: 0.20, 95% CI: 0.10–0.41, OR: 0.22, 95% CI: 0.12–0.42, respectively).

Conclusions

Our findings suggest that there is an association of IL-4 gene intron 3 VNTR polymorphism with susceptibility of a person for development of knee OA. As a result, IL-4 gene intron 3 VNTR polymorphism could be a genetic marker in OA in a Turkish study population. This is the first association study that evaluates the associations between IL-4 gene VNTR polymorphism and knee OA.     

Loss of Eph-receptor expression correlates with loss of cell adhesion and chondrogenic capacity in Hoxa13 mutant limbs.

Mesenchymal patterning is an active process whereby genetic commands coordinate cell adhesion, sorting and condensation, and thereby direct the formation of morphological structures. In mice that lack the Hoxa13 gene, the mesenchymal condensations that form the autopod skeletal elements are poorly resolved, resulting in missing digit, carpal and tarsal elements. In addition, mesenchymal and endothelial cell layers of the umbilical arteries (UAs) are disorganized, resulting in their stenosis and in embryonic death. To further investigate the role of Hoxa13 in these phenotypes, we generated a loss-of-function allele in which the GFP gene was targeted into the Hoxa13 locus. This allele allowed FACS isolation of mesenchymal cells from Hoxa13 heterozygous and mutant homozygous limb buds. Hoxa13(GFP) expressing mesenchymal cells from Hoxa13 mutant homozygous embryos are defective in forming chondrogenic condensations in vitro. Analysis of pro-adhesion molecules in the autopod of Hoxa13 mutants revealed a marked reduction in EphA7 expression in affected digits, as well as in micromass cell cultures prepared from mutant mesenchymal cells. Finally, antibody blocking of the EphA7 extracellular domain severely inhibits the capacity of Hoxa13(GFP) heterozygous cells to condense and form chondrogenic nodules in vitro, which is consistent with the hypothesis that reduction in EphA7 expression affects the capacity of Hoxa13(-/-) mesenchymal cells to form chondrogenic condensations in vivo and in vitro. EphA7 and EphA4 expression were also decreased in the mesenchymal and endothelial cells that form the umbilical arteries in Hoxa13 mutant homozygous embryos. These results suggest that an important role for Hoxa13 during limb and UA development is to regulate genes whose products are required for mesenchymal cell adhesion, sorting and boundary formation.     

Restriction fragment length polymorphism analysis of the chicken B-F and B-L genes and their association with serologically defined B haplotypes

Seven serologically defined chicken haplotypes have been analysed by restriction fragment length polymorphism (RFLP) with chicken cDNA probes specific for MHC class I and II. The results demonstrate an excellent correlation between the observed RFLP banding patterns in the investigated haplotypes and the serological B-typing. In future, RFLP analysis in addition to serological B-typing may sharpen the tools in the search for recombinant chromosomes separating B-F and B-L.     

Changes in blood lymphocyte numbers with age in vivo and their association with the levels of cytokines/cytokine receptors

Background

Alterations in the number and composition of lymphocytes and their subsets in blood are considered a hallmark of immune system aging. However, it is unknown whether the rates of change of lymphocytes are stable or change with age, or whether the inter-individual variations of lymphocyte composition are stable over time or undergo different rates of change at different ages. Here, we report a longitudinal analysis of T- and B-cells and their subsets, and NK cells in the blood of 165 subjects aged from 24 to 90 years, with each subject assessed at baseline and an average of 5.6 years follow-up.

Results

The rates of change of T-(CD4⁺ and CD8⁺) and B-cells, and NK cells were relative stable throughout the adult life. A great degree of individual variations in numbers of lymphocytes and their subsets and in the rates of their changes with age was observed. Among them, CD4⁺ T cells exhibited the highest degree of individual variation followed by NK cells, CD8⁺ T cells, and B cells. Different types of lymphocytes had distinct trends in their rates of change which did not appear to be influenced by CMV infection. Finally, the rates of CD4⁺, CD8⁺ T cells, naive CD4⁺ and naïve CD8⁺ T cells were closely positively correlated.

Conclusion

Our findings provide evidence that the age-associated changes in circulating lymphocytes were at relative stable rates in vivo in a highly individualized manner and the levels of selected cytokines/cytokine receptors in serum might influence these age-associated changes of lymphocytes in circulation.

     

Chronic exposure to low levels of antigen in the periphery causes reversible functional impairment correlating with changes in CD5 levels in monoclonal CD8 T cells

This study describes a double-transgenic model in which monoclonal CD8 F5 T cells are chronically exposed to self Ag (nucleoprotein) in the periphery, but are not affected during thymic development. Chronic exposure of CD8 T cells to their cognate Ag rendered them unable to proliferate or produce cytokines in response to antigenic stimulation in vitro. However, the cells still retained some killer function in vivo and continuously eliminated APC expressing high levels of Ag. In addition, when crossed with mice expressing Ag in the anterior pituitary gland (triple-transgenic mice), F5 T cells migrated to this site and killed growth hormone producing somatotrophs. The anergic state was reversible upon transfer into Ag-free recipients, resulting in full recovery of in vitro responsiveness to Ag. Anergic CD8 T cells express higher levels of CD5, a negative regulator of T cell signaling, whereas after transfer and residence in Ag-free hosts, CD5 levels returned to normal. This suggests that up-regulation of negative T cell regulators in peripheral T cells exposed to chronic stimulation by Ag may prevent full functionality and thus avoid overt autoreactivity.     

Frequency of fokI and taqI polymorphism of vitamin D receptor gene in Indian population and its association with 25-hydroxyvitamin D levels

BACKGROUND:

The VDR protein is at the centre of the vitamin D endocrine system, a complex physiological system with substantial feedback regulatory mechanisms involved in maintaining serum calcium and 1, 25 dihydroxy vitamin D3. Variations in VDR gene are shown to have implications in several diseases and have also been implicated as an important genetic factor affecting bone mass.

AIM:

To determine the frequency of Fok I and Taq I variants in healthy Indian individuals and its association with 25-OH-Vitamin D levels.

SETTINGS AND DESIGN:

Blood samples were collected from 143 unrelated normal individuals (Male-84 and Female-59) and their genotypes determined.

MATERIALS AND METHODS:

After amplification by polymerase chain reaction, each polymorphism was genotyped by restriction fragment length polymorphism. For 100 normal healthy individuals 25-hydroxyvitamin D estimation was done using DiaSorin kit method.

STATISTICAL ANALYSIS:

Graph pad software was used to calculate the P values from the Chi-square.

RESULTS:

Out of 143 samples analyzed for FokI and TaqI polymorphisms the following genotypic frequency was obtained FF 59%, Ff 36%, ff 5% and TT 49%, Tt 43%, tt 8% respectively.

CONCLUSIONS:

Results indicate that the distribution of the polymorphic loci Fok I and Taq I vary considerably not only in different populations, but also within India. Furthermore, when the genotypes were analyzed with respect to 25-OH-Vitamin D levels, a significant association was seen for the Taq 1 SNP but not with the Fok I.     

The dilution and loss of wetland function associated with conversion to open water

Some degree of wetland loss characterizes most coastal systems of the United States. This loss is generally reported as a decrease in wetland area, but most coastal land loss entails wetland submergence and conversion to open water. This concurrent increase in the area of aquatic habitat decreases the wetland:open water ratio, effectively diluting the area of remaining wetland relative to the aquatic system. The functional loss of intertidal wetlands to the ecosystem associated with this dilution effect may significantly alter ecological functions dependent on the interactive coupling of wetland and aquatic habitats. The magnitude of functional loss is strongly dependent on the wetland:water ratio of an estuary. In estuaries with open bay-type morphologies, the open water area is already large and functional loss of wetland by additional dilution may be only slightly greater than the areal wetland loss. Where estuaries are wetland-dominated, however, conversion of even a small percentage of wetland to water drastically alters the wetland:water ratio. In these cases, functional losses by dilution are much greater than the rate of areal wetland loss.In the Barataria Basin estuary, Louisiana, between 1967 and 1987, 15.4% of the salt marsh was lost (assuming a loss rate of 0.8% y^–1 of the remaining marsh). We estimated that this 15% loss of salt marsh, by conversion to open water, may have resulted in a 27% reduction in the supply of inorganic nutrients and organic matter to the estuarine water column by the marsh, simply due to the dilution effects of the changed wetland:open water ratio. Functional losses of this magnitude may have serious implications to the estuarine ecosystem where intertidal wetlands support aquatic productivity by exporting nutrients and energy or where intertidal wetlands buffer aquatic eutrophication by importing excess nutrients and organic matter. It is conceivable that an estuary characterized by wetland loss may reach a point where, although some wetland remains, its functional value to the ecosystem is essentially gone.     

Analysis of the porcine APOA2 gene expression in liver,polymorphism identification and association with fatty acid composition traits

APOA2 is a protein implicated in triglyceride, fatty acid and glucose metabolism. In pigs, the APOA2 gene is located on pig chromosome 4 (SSC4) in a QTL region affecting fatty acid composition, fatness and growth traits. In this study, we evaluated APOA2 as a candidate gene for meat quality traits in an Iberian × Landrace backcross population. The APOA2:c.131T>A polymorphism, located in exon 3 of APOA2 and determining a missense mutation, was associated with the percentage of hexadecenoic acid [C16:1(n–9)], linoleic acid [C18:2(n–6)], α‐linolenic acid [C18:3(n–3)], dihomo‐gamma‐linolenic acid [C20:3(n–6)] and polyunsaturated fatty acids (PUFAs) in backfat. Furthermore, this SNP was associated with the global mRNA expression levels of APOA2 in liver and was used as a marker to determine allelic expression imbalance by pyrosequencing. We determined an overexpression of the T allele in heterozygous samples with a mean ratio of 2.8 (T/A), observing a high variability in the allelic expression among individuals. This result suggests that complex regulatory mechanisms, beyond a single polymorphism (e.g. epigenetic effects or multiple cis‐acting polymorphisms), may be regulating APOA2 gene expression.     

Circulating levels of matrix proteases and their inhibitors in pregnant women with and without a history of recurrent pregnancy loss

Background  

We have recently shown that serum relaxin-2 levels are attenuated in women with a history of recurrent pregnancy loss (RPL). We sought to determine whether a history of RPL is also associated with changes in serum matrix metalloproteases (MMPs) and tissue inhibitors of matrix metalloproteases (TIMP) -1 and -2.