Water Potential Components, Stomatal Function, and Liquid Phase Water Transport Resistances of Four Arctic and Alpine Species in Relation to Moisture Stress

Transpiration measurements of two alpine tundra species, Deschampsia caespitosa and Geum rossii, and two arctic tundra species, Dupontia fischeri and Carex aquatilis, were conducted under varying atmospheric and soil moisture stress regimes to determine if the stomatal response to water stress may play a role in the local distributions of these species. Under low soil moisture stress, stomata of the species restricted typically to wet meadow areas, Deschampsia and Dupontia, did not exhibit closure until leaf water potential declined. However, when soil moisture stress was low and atmospheric stress increased, Geum and particularly Carex exhibited partial stomatal closure before leaf water potential dropped, suggesting a direct response of the stomata to the vapor pressure gradient between the leaf and the atmosphere. Lower liquid phase water transport resistance from the soil to the leaves may also reduce the development of leaf moisture stress in Geum. Furthermore, Geum and possibly Carex appeared to undergo less of a loss of leaf turgor when leaf water potential decreased. This response may serve to maintain leaf cell turgor and to abate the reduction in leaf enlargement.     

Differential Labeling of Components in Human Erythrocyte Membranes Associated with the Transport of Glucose

The irreversible inhibition of glucose transport by 1-fluoro-2,4-dinitrobenzene (FDNB) has been used to identify membrane proteins possibly associated with glucose transport in human crythrocytes. D-Glucose was shown to enhance significantly the rate of FDNB inhibition of transport when present during the reaction, whereas cytochalasin B (CB) and D-maltose retarded this FDNB inhibition of transport. This modulation of the inhibition reaction formed the basis for a double isotopic differential labeling technique using [¹⁴C]- and [³H]FDNB followed by SDS-polyacrylamide gel electrophoresis to distinguish transport-associated polypeptides from bulk membrane dinitrophenylated proteins.

Reactions in the presence of CB or maltose revealed the presence of a differentially labeled polypeptide(s), with a molecular weight of approximately 60,000-65,000 daltons. This effect could in part be reversed in the presence of D-glucose but not L-glucose. Reactions in the presence of D-glucose resulted in two regions of differential labeling. One region was around 200,000 daltons and the other corresponded to a 90,000-dalton band.

Extraction of membrane proteins with p-chloromercuribenzene sulfonate resulted in no loss of the 60,000-dalton peak, indicating that this labeled polypeptide(s) was firmly anchored in the hydrophobic core of the membrane.

These results indicate that as many as three membrane polypeptides are differentially labeled by FDNB under conditions strongly associated with the inhibition of the glucose transport system and may be involved in the regulation of glucose transport.     

Components of the Human SWI/SNF Complex Are Enriched in Active Chromatin and Are Associated with the Nuclear Matrix

Biochemical and genetic evidence suggest that the SWI/SNF complex is involved in the remodeling of chromatin during gene activation. We have used antibodies specific against three human subunits of this complex to study its subnuclear localization, as well as its potential association with active chromatin and the nuclear skeleton. Immunofluorescence studies revealed a punctate nuclear labeling pattern that was excluded from the nucleoli and from regions of condensed chromatin. Dual labeling failed to reveal significant colocalization of BRG1 or hBRM proteins with RNA polymerase II or with nuclear speckles involved in splicing. Chromatin fractionation experiments showed that both soluble and insoluble active chromatin are enriched in the hSWI/SNF proteins as compared with bulk chromatin. hSWI/SNF proteins were also found to be associated with the nuclear matrix or nuclear scaffold, suggesting that a fraction of the hSWI/SNF complex could be involved in the chromatin organization properties associated with matrix attachment regions.     

Maternal Factors Are Associated with the Expression of Placental Genes Involved in Amino Acid Metabolism and Transport

Introduction

Maternal environment and lifestyle factors may modify placental function to match the mother’s capacity to support the demands of fetal growth. Much remains to be understood about maternal influences on placental metabolic and amino acid transporter gene expression. We investigated the influences of maternal lifestyle and body composition (e.g. fat and muscle content) on a selection of metabolic and amino acid transporter genes and their associations with fetal growth.

Methods

RNA was extracted from 102 term Southampton Women’s Survey placental samples. Expression of nine metabolic, seven exchange, eight accumulative and three facilitated transporter genes was analyzed using quantitative real-time PCR.

Results

Increased placental LAT2 (p = 0.01), y ⁺ LAT2 (p = 0.03), aspartate aminotransferase 2 (p = 0.02) and decreased aspartate aminotransferase 1 (p = 0.04) mRNA expression associated with pre-pregnancy maternal smoking. Placental mRNA expression of TAT1 (p = 0.01), ASCT1 (p = 0.03), mitochondrial branched chain aminotransferase (p = 0.02) and glutamine synthetase (p = 0.05) was positively associated with maternal strenuous exercise. Increased glutamine synthetase mRNA expression (r = 0.20, p = 0.05) associated with higher maternal diet quality (prudent dietary pattern) pre-pregnancy. Lower LAT4 (r = -0.25, p = 0.05) and aspartate aminotransferase 2 mRNA expression (r = -0.28, p = 0.01) associated with higher early pregnancy diet quality. Lower placental ASCT1 mRNA expression associated with measures of increased maternal fat mass, including pre-pregnancy BMI (r = -0.26, p = 0.01). Lower placental mRNA expression of alanine aminotransferase 2 associated with greater neonatal adiposity, for example neonatal subscapular skinfold thickness (r = -0.33, p = 0.001).

Conclusion

A number of maternal influences have been linked with outcomes in childhood, independently of neonatal size; our finding of associations between placental expression of transporter and metabolic genes and maternal smoking, physical activity and diet raises the possibility that their effects are mediated in part through alterations in placental function. The observed changes in placental gene expression in relation to modifiable maternal factors are important as they could form part of interventions aimed at maintaining a healthy lifestyle for the mother and for optimal fetal development.     

Aluminum Toxicity Is Associated with Mitochondrial Dysfunction and the Production of Reactive Oxygen Species in Plant Cells

Potential mechanisms of Al toxicity measured as Al-induced inhibition of growth in cultured tobacco cells (Nicotiana tabacum, nonchlorophyllic cell line SL) and pea (Pisum sativum) roots were investigated. Compared with the control treatment without Al, the accumulation of Al in tobacco cells caused instantaneously the repression of mitochondrial activities [monitored by the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and the uptake of Rhodamine 123] and, after a lag of about 12 h, triggered reactive oxygen species (ROS) production, respiration inhibition, ATP depletion, and the loss of growth capability almost simultaneously. The presence of an antioxidant, butylated hydroxyanisol, during Al treatment of SL cells prevented not only ROS production but also ATP depletion and the loss of growth capability, suggesting that the Al-triggered ROS production seems to be a cause of ATP depletion and the loss of growth capability. Furthermore, these three late events were similarly repressed in an Al-tolerant cell line (ALT301) isolated from SL cells, suggesting that the acquisition of antioxidant functions mimicking butylated hydroxyanisol can be a mechanism of Al tolerance. In the pea root, Al also triggered ROS production, respiration inhibition, and ATP depletion, which were all correlated with inhibition of root elongation. Taken together, we conclude that Al affects mitochondrial functions, which leads to ROS production, probably the key critical event in Al inhibition of cell growth.     

Marine N-3 Polyunsaturated Fatty Acids Are Inversely Associated with Risk of Type 2 Diabetes in Asians: A Systematic Review and Meta-Analysis

Background

Prospective cohort studies in relation to the associations between n-3 polyunsaturated fatty acids (PUFA) and risk of type 2 diabetes (T2D) were inconsistent. Differences in tissue n-3 PUFA compositions in subjects with and without T2D were also inconsistent in both cohort and case-control studies. We conducted a systematic review and meta-analysis of prospective cohort studies to examine the associations of fish and n-3 PUFA intake with T2D risk. The differences in tissue n-3 PUFA compositions in subjects with and without T2D were investigated based on cohort and case-control studies.

Methods and Findings

PubMed, Embase, Cochrane library, China National Knowledge Infrastructure (CNKI) and Chinese VIP database up to January 2012 was used to identify relevant studies, and reference lists from retrieved studies were reviewed. Two authors independently extracted the data. Random-effects models were used to pool the summary relative risk (RR). Twenty-four studies including 24,509 T2D patients and 545,275 participants were identified. For cohort studies, the summary RR of T2D for the highest vs lowest categories of total fish, marine n-3 PUFA and alpha-linolenic acid intake was 1.07 (95% CI: 0.91, 1.25), 1.07 (95% CI: 0.95, 1.20) and 0.93 (95% CI: 0.81, 1.07), respectively. Subgroup analyses indicated that summary RR (highest vs lowest category) of T2D for fish and marine n-3 PUFA intake was 0.89 (95% CI: 0.81, 0.98) and 0.87 (95% CI: 0.79, 0.96) for Asian populations, and 1.20 (95% CI: 1.01, 1.44) and 1.16 (95% CI: 1.04, 1.28) for Western populations. Asian subjects with T2D had significantly lower tissue compositions of C22∶6n-3 (SMD: −1.43; 95% CI: −1.75, −1.12) and total n-3 PUFA (SMD: −1.41; 95% CI: −2.23, −0.59) compared with those without T2D.

Conclusion

This systematic review and meta-analysis provides evidence that marine n-3 PUFA have beneficial effects on the prevention of T2D in Asian populations.     

Fatty Acid Diversity is Not Associated with Neutral Genetic Diversity in Native Populations of the Biodiesel Plant Jatropha curcas L.

Jatropha curcas L. (Euphorbiaceae) is a shrub native to Mexico and Central America, which produces seeds with a high oil content that can be converted to biodiesel. The genetic diversity of this plant has been widely studied, but it is not known whether the diversity of the seed oil chemical composition correlates with neutral genetic diversity. The total seed oil content, the diversity of profiles of fatty acids and phorbol esters were quantified, also, the genetic diversity obtained from simple sequence repeats was analyzed in native populations of J. curcas in Mexico. Using the fatty acids profiles, a discriminant analysis recognized three groups of individuals according to geographical origin. Bayesian assignment analysis revealed two genetic groups, while the genetic structure of the populations could not be explained by isolation‐by‐distance. Genetic and fatty acid profile data were not correlated based on Mantel test. Also, phorbol ester content and genetic diversity were not associated. Multiple linear regression analysis showed that total oil content was associated with altitude and seasonality of temperature. The content of unsaturated fatty acids was associated with altitude. Therefore, the cultivation planning of J. curcas should take into account chemical variation related to environmental factors.     

Low-Density Granulocytes Are Elevated in Mycobacterial Infection and Associated with the Severity of Tuberculosis

Tuberculosis remains a global health problem caused by infection with Mycobacterium tuberculosis. Numerous studies have established a close correlation between the development of tuberculosis and the roles of neutrophils. Recently, a distinct population of CD15⁺ granulocytes was found to be present in the peripheral blood mononuclear cell (PBMC) fraction in humans. This population of granulocytes, termed low-density granulocytes (LDGs), was reported to be elevated and associated with disease activity or severity in a number of different conditions including SLE, asthma and HIV infection. However, both the frequency and clinical significance of LDGs associated with tuberculosis are unclear. Here we determined LDG levels and made comparisons between subjects with active pulmonary tuberculosis (PTB) and healthy controls, between PTB patients with mild-to-moderate disease and patients with advanced disease, and among PTB patients following anti-tuberculous therapy of varying durations. The direct correlation between M. tuberculosis infection and LDG levels was confirmed by in vitro infection of whole peripheral blood and isolated granulocytes with mycobacteria. Our results demonstrated that PBMCs in PTB patients contained significantly elevated percentages of LDGs compared with control subjects. LDGs in tuberculosis expressed higher levels of activation markers compared to normal-density granulocytes (NDGs). M. tuberculosis induced the generation of LDGs in both whole blood and isolated NDGs from control subjects, which suggests that LDGs associated with M. tuberculosis infection are likely to originate from in situ activation. Furthermore, our results revealed that the frequency of LDGs is associated with the severity of tuberculosis.     

Low Blood Long Chain Omega-3 Fatty Acids in UK Children Are Associated with Poor Cognitive Performance and Behavior: A Cross-Sectional Analysis from the DOLAB Study

Background

Omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), especially DHA (docosahexaenonic acid) are essential for brain development and physical health. Low blood Omega-3 LC-PUFA have been reported in children with ADHD and related behavior/learning difficulties, as have benefits from dietary supplementation. Little is known, however, about blood fatty acid status in the general child population. We therefore investigated this in relation to age-standardized measures of behavior and cognition in a representative sample of children from mainstream schools.

Participants

493 schoolchildren aged 7–9 years from mainstream Oxfordshire schools, selected for below average reading performance in national assessments at age seven.

Method

Whole blood fatty acids were obtained via fingerstick samples. Reading and working memory were assessed using the British Ability Scales (II). Behaviour (ADHD-type symptoms) was rated using the revised Conners’ rating scales (long parent and teacher versions). Associations were examined and adjusted for relevant demographic variables.

Results

DHA and eicosapentaenoic acid (EPA), accounted for only 1.9% and 0.55% respectively of total blood fatty acids, with DHA showing more individual variation. Controlling for sex and socio-economic status, lower DHA concentrations were associated with poorer reading ability (std. OLS coeff. = 0.09, p = <.042) and working memory performance (0.14, p = <.001). Lower DHA was also associated with higher levels of parent rated oppositional behavior and emotional lability (−0.175, p = <.0001 and −0.178, p = <.0001).

Conclusions

In these healthy UK children with below average reading ability, concentrations of DHA and other Omega-3 LC-PUFA were low relative to adult cardiovascular health recommendations, and directly related to measures of cognition and behavior. These findings require confirmation, but suggest that the benefits from dietary supplementation with Omega-3 LC-PUFA found for ADHD, Dyspraxia, Dyslexia, and related conditions might extend to the general school population.     

Scolex Glands Associated with the Rostella in Three Species of the Dilepididae (Cestoda: Cyclophyllidea)

The microanatomy, fine structure and cytochemistry of scolex glands of Vitta riparia, Angularella beema and Trichocephaloidis megalocephala are examined by light and electron microscopy. Cytochemical tests include PAS, mercury bromphenol blue and performic acid-alcian blue for light microscopy and periodic acid-thiocarbohydrazide-OsO₄ for electron microscopy. The scolex glands are organized in two spatially isolated syncytia, one located in the rostellum, the other in the rostellar sac. The cytoplasm of the gland syncytia is characterized by a high affinity for haematoxylin. Cytochemical tests indicate the presence of moderate amounts of glycoprotein in the glands. A specialized type of secretion—dark oval or ovoid bodies with diameter 0.3–0.5 μm are observed by EM in both the rostellum glands and the rostellar-sac glands of V. riparia and T. megalocephala , and in the rostellar-sac gland of A. beema . The rostellum gland of A. beema produces larger dark oval bodies measuring up to 0.9 μm. Lipid droplets are also observed in the glandular cytoplasm. Some tegumental cytons containing discoid bodies are found between the glandular perikarya. The glandular products and the lipid droplets are secreted via the rostellar tegument. © 1997 Published by Elsevier Science Ltd on behalf of The Royal Swedish Academy of Sciences.     

The Entomostracan and Rotifer Communities Associated with Submerged Plants in the Norfolk Broadland — Effects of Plant Biomass and Species Composition

The microcrustacean and rotifer communities associated with submerged aquatic plants were studied over a three-year period in a series of experimental ponds, created within a fenland drainage ditch. Seasonal abundance and spatial distributions were assessed. The ponds contained a varying amount of vegetation, dominated either by Ceratophyllum demersum or Stratiotes aloides and this had consequences for the ponds' animal communities. Increasing densities of Ceratophyllum were associated with increases in weed-associated entomostracans whereas increases in Stratiotes led to a general decrease in associated animals. Increases in both plant species led to reductions in abundance of Daphnia, but to differing amounts. A relatively low density plant population in the presence of zooplanktovorous fish did not provide a refuge from predation for large-bodied Cladocera.     

Low Density Membranes Are Associated with RNA-binding Proteins and Thylakoids in the Chloroplast of Chlamydomonas reinhardtii

Chloroplast subfractions were tested with a UV cross-linking assay for proteins that bind to the 5′ untranslated region of the chloroplast psbC mRNA of the green alga Chlamydomonas reinhardtii. These analyses revealed that RNA-binding proteins of 30–32, 46, 47, 60, and 80 kD are associated with chloroplast membranes. The buoyant density and the acyl lipid composition of these membranes are compatible with their origin being the inner chloroplast envelope membrane. However, unlike previously characterized inner envelope membranes, these membranes are associated with thylakoids. One of the membrane-associated RNA-binding proteins appears to be RB47, which has been reported to be a specific activator of psbA mRNA translation. These results suggest that translation of chloroplast mRNAs encoding thylakoid proteins occurs at either a subfraction of the chloroplast inner envelope membrane or a previously uncharacterized intra-chloroplast compartment, which is physically associated with thylakoids.     

Variants of the Coagulation and Inflammation Genes Are Replicably Associated with Myocardial Infarction and Epistatically Interact in Russians

Background

In spite of progress in cardiovascular genetics, data on genetic background of myocardial infarction are still limited and contradictory. This applies as well to the genes involved in inflammation and coagulation processes, which play a crucial role in the disease etiopathogenesis.

Methods and Results

In this study we found genetic variants of TGFB1, FGB and CRP genes associated with myocardial infarction in discovery and replication groups of Russian descent from the Moscow region and the Republic of Bashkortostan (325/185 and 220/197 samples, correspondingly). We also found and replicated biallelic combinations of TGFB1 with FGB, TGFB1 with CRP and IFNG with PTGS1 genetic variants associated with myocardial infarction providing a detectable cumulative effect. We proposed an original two-component procedure for the analysis of nonlinear (epistatic) interactions between the genes in biallelic combinations and confirmed the epistasis hypothesis for the set of alleles of IFNG with PTGS. The procedure is applicable to any pair of logical variables, e.g. carriage of two sets of alleles. The composite model that included three single gene variants and the epistatic pair has AUC of 0.66 both in discovery and replication groups.

Conclusions

The genetic impact of TGFB1, FGB, CRP, IFNG, and PTGS and/or their biallelic combinations on myocardial infarction was found and replicated in Russians. Evidence of epistatic interactions between IFNG with PTGS genes was obtained both in discovery and replication groups.     

Oxygen Transport in the Salt Marsh Genus Puccinellia with Particular Reference to the Diffusive Resistance of the Root--Shoot Junction and the use of Paraffin Oil as a Diffusive Barrier in Plant Studies

Results are presented which contradict previous reports thatin the graminaceous genus Puccinellia the root-shoot junctionhas a high diffusive resistance which severely restricts oxygentransfer from shoot to root. No such restriction was evidentin P. maritima, P. festuciformis var.festuciformis, and P. festucfformisvar.intermedia(= P. peisonis) and the plants produced well-developedroot systems in permanently flooded soils. The evidence obtainedsupports the view that, whether the root systems are whollyor only partially submerged by soil flooding the shoot is themajor source or entry point for oxygen required by the roots;also, that oxygen passes more readily from shoot to root thanit does through the wall cells of the root base. It is pointed out that paraffin oil is an undesirable productto employ as a diffusion barrier in studies of root aeration. Key words: Puccinellia, Oxygen transport, Diffusive resistance, Polarography     

Evaluation of Phosphorus Species in the Bed Sediments of an Atlantic Basin: Bioavailability and Relation with Surface Active Components of the Sediment

In this study, total phosphorus (P) concentrations and P fractions in the bed sediments of the Anllóns River (NW Spain) have been examined. The Lowest Effect Level of the Ontario Sediment Quality Guidelines was trespassed for total phosphorus (600 mg kg^?1) at three out of the five sampling sites which, in addition, showed an average of 43% of bioavailable phosphate. The inorganic P fractions (loosely bound P, redox-sensitive P, metal oxide-bound P, carbonate and apatite P, and residual P) showed that inorganic P was mostly found as metal oxide bound P. The difference between total phosphorus and the sum of the inorganic P forms determined in these extracts is attributed to P associated to organic compounds being solubilized in some of the extractants, and represented in average 58% of total phosphorus. With the exception of loosely bound P, all the P fractions showed significant positive correlations with each other and with total phosphorus.     

Metabolism of Poly(A) in Plant Cells: Discrete Classes Associated with Free and Membrane-bound Polysomes

In the subapical region of dark-grown pea epicotyls about 40% of the total polysomes are associated with membranes. The presence of poly(A) in polysomal mRNA was detected by hybridization of unlabeled RNA with (3)H-poly(U). Both free mRNA and messenger ribonucleoprotein particles in polysomes hybridize with (3)H-poly(U) quantitatively. The binding of (3)H-poly(U) to polysomes is increased by treatment with the detergent sodium dodecyl sulfate. Since detergent influenced the (3)H-poly(U) binding more in membrane-bound polysomes than in free, there may be more protein(s) associated with the poly(A) portion of the mRNA in membrane-bound polysomes. Analysis of the poly(A) segments isolated from the mRNA of these two classes of polysomes indicates that there are discrete classes of poly(A) and they appear to be differentially associated with free and membrane-bound polysomes. Mean size distribution of poly(A) in free polysomes is larger than in membrane-bound polysomes.Following treatment (2 days) with the plant growth hormone indoleacetic acid, there is a gradual decrease in the mean length of total poly(A), which appears to correspond to a decrease in the size of the polysomes and their associated mRNA.