Carbon Accumulation in Neotropical Dry Secondary Forests: The Roles of Forest Age and Tree Dominance and Diversity

Tropical secondary forests are important sinks for atmospheric carbon, yet C uptake and accumulation rates are highly uncertain, and the mechanisms poorly understood. We evaluated the recovery of C stocks in four pools (aboveground biomass, litter, roots and topsoil) during dry forest regrowth by combining a space for time replacement (that is, a chronosequence) with a repeated measurements approach (that is, a resampling). We fit nonlinear models to chronosequence data to test whether forest age could explain differences in C stocks across sites, and to changes in aboveground biomass calculated from resampling over two 3-year periods, to test the predictive potential of forest age. We combined data from both approaches into structural equation models (SEM) to assess forest age and tree community attributes (diversity and dominance) as drivers of C stocks and changes in aboveground biomass. Forest age explained differences across sites in C stocks for aboveground biomass, litter and live roots, but not for the remaining pools. Observed C stock changes in aboveground biomass were poorly predicted by forest age. SEM revealed that aboveground biomass C was consistently and positively related to forest age and to the community weighted mean of maximum tree height (H _max CWM), but not to tree diversity. Observed C stock changes were related only to H _max CWM, although not consistently across the two 3-year periods. Our results highlight that the chronosequence approach can yield reasonable insights into long-term C accumulation trends, but erroneous estimates of C change over specific time periods. They also show that, in addition to age, dominance by tall statured species, but not tree species diversity, plays a significant role in C accumulation.     

Screening for Fabry disease in patients undergoing dialysis for chronic renal failure in Turkey: Identification of new case with novel mutation

Background

Chronic renal failure (CRF) is a serious complication of Fabry disease (FD). The aims of the present study were to determine the prevalence of unrecognized FD in Turkish hemodialysis population and to investigate the molecular background.

Method

Primarily, α-galactosidase A (α-Gal A) activity was investigated on DBS in 1136 patients of both sexes who underwent dialysis for CRF in Turkey. The disease was confirmed by analyzing enzyme activity in leukocyte and GLA gene sequencing in all patients in whom α-Gal A level was 40% of normal or less.

Results

Mean age of the patients (44.5% female, 52.5% male) was 56.46 ± 15.85 years. Enzyme activity was found low with DBS method in 12 patients (four males, eight females). Two men, but no women, were diagnosed with FD by enzymatic and molecular analysis. In consequence of genetic analysis of a case, a new mutation [hemizygote c.638C>T (p.P214S) missense mutation in exon 5] was identified, which was not described in literature. Family screening of cases identified six additional cases.

Conclusion

As a result of this initial screening study performed on hemodialysis patients for the first time with DBS method in Turkey, the prevalence of FD was detected as 0.17%. Although the prevalence seems to be low, screening studies are of great importance for detecting hidden cases as well as for identifying other effected family members.     

Effect of acute maximal aerobic exercise upon the trace element levels in blood

This study was carried out in order to determine the effect of acute maximal aerobic exercise on the copper and zinc levels in blood. The study was participated by 16 healthy male university students with an average age of 19.44+/-1.63. There were 5 cc blood samples taken from the participants before and after they had been subjected to aerobic loading process (20 m shuttle run). The copper and zinc levels in the blood samples were determined by the use of Anodic Stripping Voltammetry (ASV) technique. The data obtained were evaluated by simple t test and SPSS software. The results revealed the fact that the blood Zn levels of the participants increased and Cu levels decreased with statistical significant extent (p<0.01) after maximal aerobic loading. There found no correlation between the maximal aerobic power levels (Max VO2) of the participants and their resting copper and zinc blood levels. However blood zinc and Max VO2 levels of the participants were positively correlated after maximal aerobic loading. The participants were fed on a zinc and copper free diet six week prior to the program. They were also asked not to use copper and zinc containing vitamins during this period.     

Hydrogen Sulfide: A Novel Gaseous Molecule for Plant Adaptation to Stress

Hydrogen sulfide (H₂S) has emerged as a novel gaseous signal molecule with multifarious effects on seed germination, plant growth, development, and physiological processes. Due to its dominant role in plant stress tolerance and cross-adaptation, it is getting more attention nowadays, although it has been largely referred as toxic and environmental hazardous gas. In this review work, we are highlighting the importance of H₂S as an essential gaseous molecule to help in signaling, metabolism, and stress tolerance in plants. Firstly, production of H₂S from different natural and artificial sources were discussed with its transformation from sulfur (S) to sulfate (SO₄²⁻) and then to sulfite (SO₃²⁻). The importance of different kinds of transporters that helps to take SO₄²⁻ from the soil solution was presented. Mainly, these transporters are SULTRs (H⁺/SO₄²⁻ cotransporters) and multigene family encodes them. Furthermore, these SULTRs have LAST (Low affinity transport proteins), HAST (High affinity transport proteins), vacuole transporters, and plastid transporters. Since it is well known that there is strong relationship between SO₄²⁻ and synthesis of hydrogen sulfide or dihydrogen sulfide or sulfane in plant cells. Thus, cysteine (Cys) metabolism through which H₂S could be generated in plant cell with the role of different enzymes has been presented. Furthermore, H₂S in interaction with other molecules could help to mitigate biotic and abiotic stress. Based on this review work, it can be concluded that H₂S has potential to induce cross-adaptation to biotic and abiotic stress; thus, it is recommended that it should be considered in future studies to answer the questions like what are the receptors of H₂S in plant cell, where in plants the physiological concentration of H₂S is high in response to multiple stress and how it induces cross-adaptation by interaction with other signal molecules.

     

Drought Tolerance Strategies in Plants: A Mechanistic Approach

Journal of Plant Growth Regulation - Anthropogenic activities in the past and present eras have created global warming and consequently a storm of drought stress, affecting both plants and animals....     

Lactate Dehydrogenase Like Crystallin: A Potentially Protective Shield for Indian Spiny-Tailed Lizard (Uromastyx hardwickii) Lens Against Environmental Stress?

Taxon specific lens crystallins in vertebrates are either similar or identical with various metabolic enzymes. These bifunctional crystallins serve as structural protein in lens along with their catalytic role. In the present study, we have partially purified and characterized lens crystallin from Indian spiny-tailed lizard (Uromastyx hardwickii). We have found lactate dehydrogenase (LDH) activity in lens indicating presence of an enzyme crystallin with dual functions. Taxon specific lens crystallins are product of gene sharing or gene duplication phenomenon where a pre-existing enzyme is recruited as lens crystallin in addition to structural role. In lens, same gene adopts refractive role in lens without modification or loss of pre-existing function during gene sharing phenomenon. Apart from conventional role of structural protein, LDH activity containing crystallin in U. hardwickii lens is likely to have adaptive characteristics to offer protection against toxic effects of oxidative stress and ultraviolet light, hence justifying its recruitment. Taxon specific crystallins may serve as good models to understand structure–function relationship of these proteins.     

Molecular cytogenetic analysis reveals the existence of two independent neo-XY sex chromosome systems in Anatolian Pamphagidae grasshoppers

Background

Neo-XY sex chromosome determination is a rare event in short horned grasshoppers, but it appears with unusual frequency in the Pamphagidae family. The neo-Y chromosomes found in several species appear to have undergone heterochromatinization and degradation, but this subject needs to be analyzed in other Pamphagidae species. We perform here karyotyping and molecular cytogenetic analyses in 12 Pamphagidae species from the center of biodiversity of this group in the previously-unstudied Anatolian plateau.

Results

The basal karyotype for the Pamphagidae family, consisting of 18 acrocentric autosomes and an acrocentric X chromosome (2n♂?=?19, X0; 2n♀?=?20, XX), was found only in G. adaliae. The karyotype of all other studied species consisted of 16 acrocentric autosomes and a neo-XY sex chromosome system (2n♂♀?=?18, neo-XX♀/neo-XY♂). Two different types of neo-Y chromosomes were found. One of them was typical for three species of the Glyphotmethis genus, and showed a neo-Y chromosome being similar in size to the XR arm of the neo-X, with the addition of two small subproximal interstitial C-blocks. The second type of the neo-Y chromosome was smaller and more heterochromatinized than the XR arm, and was typical for all Nocarodeini species studied. The chromosome distribution of C-positive regions and clusters of ribosomal DNA (rDNA) and telomeric repeats yielded additional information on evolution of these neo-XY systems.

Conclusion

Most Pamphagidae species in the Anatolian region were found to have neo-XY sex chromosome systems, belonging to two different evolutionary lineages, marked by independent X-autosome fusion events occurred within the Trinchinae and Pamphaginae subfamilies. The high density of species carrying neo-XY systems in the Anatolian region, and the different evolutionary stage for the two lineages found, one being older than the other, indicates that this region has a long history of neo-XY sex chromosome formation.

     

Structural and functional characteristics of plant proteinase inhibitor-II (PI-II) family

Plant proteinase inhibitor-II (PI-II) proteins are one of the promising defensive proteins that helped the plants to resist against different kinds of unfavorable conditions. Different roles for PI-II have been suggested such as regulation of endogenous proteases, modulation of plant growth and developmental processes and mediating stress responses. The basic knowledge on genetic and molecular diversity of these proteins has provided significant insight into their gene structure and evolutionary relationships in various members of this family. Phylogenetic comparisons of these family genes in different plants suggested that the high rate of retention of gene duplication and inhibitory domain multiplication may have resulted in the expansion and functional diversification of these proteins. Currently, a large number of transgenic plants expressing PI-II genes are being developed for enhancing the defensive capabilities against insects, bacteria and pathogenic fungi. Much emphasis is yet to be given to exploit this ever expanding repertoire of genes for improving abiotic stress resistance in transgenic crops. This review presents an overview about the current knowledge on PI-II family genes, their multifunctional role in plant defense and physiology with their potential applications in biotechnology.     

Vitamin A cycle byproducts impede dark adaptation

Impaired dark adaptation (DA), a defect in the ability to adjust to dimly lit settings, is a universal hallmark of aging. However, the mechanisms responsible for impaired DA are poorly understood. Vitamin A byproducts, such as vitamin A dimers, are small molecules that form in the retina during the vitamin A cycle. We show that later in life, in the human eye, these byproducts reach levels commensurate with those of vitamin A. In mice, selectively inhibiting the formation of these byproducts, with the investigational drug C20D₃-vitamin A, results in faster DA. In contrast, acutely increasing these ocular byproducts through exogenous delivery leads to slower DA, with otherwise preserved retinal function and morphology. Our findings reveal that vitamin A cycle byproducts alone are sufficient to cause delays in DA and suggest that they may contribute to universal age-related DA impairment. Our data further indicate that the age-related decline in DA may be tractable to pharmacological intervention by C20D₃-vitamin A.     

Risk alleles for systemic lupus erythematosus in a large case-control collection and associations with clinical subphenotypes

Systemic lupus erythematosus (SLE) is a genetically complex disease with heterogeneous clinical manifestations. Recent studies have greatly expanded the number of established SLE risk alleles, but the distribution of multiple risk alleles in cases versus controls and their relationship to subphenotypes have not been studied. We studied 22 SLE susceptibility polymorphisms with previous genome-wide evidence of association (p<5×10⁻⁸) in 1919 SLE cases from 9 independent Caucasian SLE case series and 4813 independent controls. The mean number of risk alleles in cases was 15.1 (SD 3.1) while the mean in controls was 13.1 (SD 2.8), with trend p = 4×10⁻¹²⁸. We defined a genetic risk score (GRS) for SLE as the number of risk alleles with each weighted by the SLE risk odds ratio (OR). The OR for high-low GRS tertiles, adjusted for intra-European ancestry, sex, and parent study, was 4.4 (95% CI 3.8–5.1). We studied associations of individual SNPs and the GRS with clinical manifestations for the cases: age at diagnosis, the 11 American College of Rheumatology classification criteria, and double-stranded DNA antibody (anti-dsDNA) production. Six subphenotypes were significantly associated with the GRS, most notably anti-dsDNA (OR_high-low = 2.36, p = 9e−9), the immunologic criterion (OR_high-low = 2.23, p = 3e−7), and age at diagnosis (OR_high-low = 1.45, p = 0.0060). Finally, we developed a subphenotype-specific GRS (sub-GRS) for each phenotype with more power to detect cumulative genetic associations. The sub-GRS was more strongly associated than any single SNP effect for 5 subphenotypes (the above plus hematologic disorder and oral ulcers), while single loci are more significantly associated with renal disease (HLA-DRB1, OR = 1.37, 95% CI 1.14–1.64) and arthritis (ITGAM, OR = 0.72, 95% CI 0.59–0.88). We did not observe significant associations for other subphenotypes, for individual loci or the sub-GRS. Thus our analysis categorizes SLE subphenotypes into three groups: those having cumulative, single, and no known genetic association with respect to the currently established SLE risk loci.