Plasma membrane and cell wall properties of an aspen hybrid (Populus tremula × tremuloides) parenchyma cells under the influence of salt stress

The effect of salinity on cell turgor, plasma membrane permeability and cell wall elasticity has been measured in petioles of an aspen hybrid using the cell pressure probe. Control plants were grown in soil without the addition of NaCl and treated plants were grown in soil with 50 mM of NaCl for 1, 2, 3 and 4 weeks. In parenchyma cells from Populus tremula × tremuloides petioles with an increased level of NaCl in the soil: (a) turgor pressure was reduced after 1 week of treatment but afterward it was similar to untreated plants, (b) the value of elastic modulus of the cell walls increased, and (c) hydraulic conductivity of the plasma membrane of treated plants decreased in comparison to untreated ones. No histological differences and distribution of JIM5 antibody between the petioles of plants grown under salinity and the untreated were found. In cell walls of parenchyma and collenchyma from plants grown under salinity, the presence of pectic epitopes recognized by JIM7 antibodies was increased in comparison to the control plants. The obtained results indicate that under salt stress the permeability of water through plasma membrane is disturbed, cell walls became more rigid but the turgor pressure did not change.     

An ant–plant mutualism induces shifts in the protist community structure of a tank-bromeliad

Although ants may induce community-wide effects via changes in physical habitats in terrestrial environments, their influence on aquatic communities living in plant-held waters remains largely underexplored. The neotropical tank-bromeliad Aechmea mertensii (Bromeliaceae) occurs along forest edges in ant-gardens initiated by Camponotus femoratus or by Pachycondyla goeldii. Its leaves form wells that hold rainwater and provide suitable habitats for many aquatic organisms. We postulated that these ant–plant mutualisms indirectly affect the microbial community structure via changes in the environmental conditions experienced by the plants. To test this hypothesis, we analyzed the protist communities from 63 tank-bromeliads associated with either C. femoratus or P. goeldii (hereafter Cf-Aechmea and Pg-Aechmea) along a forest edge in French Guiana. For each plant, a large number of environmental variables (including habitat structure, food resources, incident radiation and the presence of aquatic invertebrates) were quantified to determine their relative importance in driving any observed differences across ant-associated plants. Pg-Aechmea are located in sun-exposed areas and hold low volumes of water and low amounts of detritus, whereas Cf-Aechmea are located in partially shaded areas and accumulate higher amounts of water and detritus. Protists (i.e., protozoa and algae) inhabiting Cf-Aechmea exhibit greater richness and abundances than those in Pg-Aechmea. Variations in detritus content, number of leaves, incident radiation, and the epiphyte richness of the ant-garden were the main factors explaining the variation in protist richness. A shift in the functional group composition of protists between bromeliads tended by different ant species suggested that mutualistic ants indirectly mediate changes in the microbial food web.     

Genetic polymorphism at the κ chain locus in mice: Comparisons of restriction enzyme hybridization fragments of variable and constant region genes

Variable (V) and constant (C) region genes of the mouse kappa light chain have been compared in inbred strains and in geographically isolated or genetically separated populations of mice by Southern blot analysis of endonuclease-restricted germline DNA. In most cases, the C gene is found on a single restriction fragment while the V genes of the V19 and V21 groups are each found on several (6–18) fragments. The restriction fragment (RF) patterns of V19 and V21 groups are both polymorphic when compared among inbred mouse strains. Southern blot patterns of V21 and V19 of inbred strains are also found among some geographically isolated populations of mice, suggesting that inbred strains acquired kappa loci from different subspecies. Some populations of geographical isolates show V21, V19, and C contexts similar to inbred mice while more distantly related species within the genus Mus and laboratory rats show no apparent similarity in context to inbred strains. Variable region genes determining the RF patterns of V19 and V21 appear to be linked to each other and to the C and Lyt-3 loci.     

Can sexual selection and disassortative mating contribute to the maintenance of a shell color polymorphism in an intertidal marine snail?

Littorina fabalis is an intertidal snail commonly living on the brown algae Fucus vesiculosus and showing frequent shell-color polymorphisms in the wild.The evolutionary mechanism underlying this polymorphism is currently unknown.Shell color variation was studied in mated and non-mated specimens of this species from different microareas in one locality from NW Spain,in order to estimate sexual selection and assortative mating that may (still) be operating in this population.The analyses across microareas allowed us to investigate frequency-dependent selection and assortative mating components,mechanisms that could maintain the polymorphism.The presence of shell scars caused by crab attacks,an environmental variable not related with sexual selection or assortative mating,was used as experimental control.This study provides new evidence of significant disassortative mating and some degree of sexual selection against some shell colors,supporting the results found 21 years ago in a similar study,i.e.in the same species and locality.The similarity of these estimates during the studied period suggests that this experimental approach is consistent and valid to be extended to other populations and organisms.In addition,sexual selection and assortative mating estimates did not change across microarens differing in shell color frequencies,suggesting than the polymorphism can not be maintained by a frequency-dependent (sexual selection-based) mechanism.Our main hypothesis is that negative assortative mating could contribute to the maintenance of the polymorphism,perhaps by males showing distinct female color preferences when searching for mates.     

An olfactory receptor pseudogene whose function emerged in humans: a case study in the evolution of structure–function in GPCRs

Human olfactory receptor, hOR17-210, is identified as a pseudogene in the human genome. Experimental data has shown however, that the gene product of frame-shifted, cloned hOR17-210 cDNA was able to bind an odorant-binding protein and is narrowly tuned for excitation by cyclic ketones. Supported by experimental results, we used the bioinformatics methods of sequence analysis (genome-wide and pair-wise), computational protein modeling and docking, to show that functionality in this receptor is retained due to sequence-structure features not previously observed in mammalian ORs. This receptor does not possess the first two transmembrane helical domains (of seven typically seen in GPCRs). It however, possesses an additional TM that has not been observed in other human olfactory receptors. By incorporating these novel structural features, we created two putative models for this receptor. We also docked odor ligands that were experimentally shown to bind hOR17-210. We show how and why structural modifications of OR17-210 do not hinder this receptor's functionality. Our studies reveal that novel gene rearrangements that result in sequence and structural diversity may have a bearing on OR and GPCR function and evolution.     

Length polymorphism in the pro α2(I) collagen gene: an alternative explanation in a case of Marfan syndrome

Summary A 38 base pair (bp) insertion in the pro 2(I) collagen gene (COL1A2) of a patient with Marfan syndrome has been proposed to be the possible cause of the disease (Henke et al. 1985). However, analysis of this insertion in DNA from the patient in question and from random normal individuals reveals it to be a common polymorphism. We suggest that the 38 bp insertion is not related to the primary defect in this case of Marfan syndrome.     

Molecular variation at the apolipoprotein B gene locus in relation to lipids and cardiovascular disease: a systematic meta-analysis

Apolipoprotein B (apoB) is the sole protein component of low-density lipoprotein (LDL) and is thought to play an important role in atherogenesis. We performed a meta-analysis of the associations between the three most frequently investigated polymorphisms (XbaI, signal peptide insertion/deletion, EcoRI) in the apolipoprotein B (APOB) gene, lipid parameters, and the risk of ischemic heart disease (IHD). We restricted our analysis to Caucasians. Homozygotes for the XbaI X+ allele had significantly elevated levels of LDL cholesterol (LDL-C) and apoB, but a decreased risk (OR=0.80; 95%CI: 0.66–0.96) of IHD. Homozygosity for the signal peptide deletion allele was associated with similarly increased levels of LDL-C and apoB, and with an increased risk of IHD (OR=1.30; 95%CI: 1.08–1.58). Subjects homozygous for the rare EcoRI allele had significantly decreased levels of total and LDL cholesterol, but unaltered risk of IHD. We conclude that all three polymorphic apoB sites are associated with altered lipid levels, but not necessarily with a consistently altered risk of IHD. These data suggest that the relationship between apoB levels, hypercholesterolemia and IHD risk cannot have a simple molecular basis in the apoB gene.     

Does origin always matter? Evaluating the influence of nonlocal seed provenances for ecological restoration purposes in a widespread and outcrossing plant species

For restoration purposes, nature conservation generally enforces the use of local seed material based on the “local‐is‐best” (LIB) approach. However, in some cases recommendations to refrain from this approach have been made. Here we test if a common widespread species with no obvious signs of local adaptation may be a candidate species for abandoning LIB during restoration. Using 10 microsatellite markers we compared population genetic patterns of the generalist species Daucus carota in indigenous and formerly restored sites (nonlocal seed provenances). Gene diversity overall ranged between H_e = 0.67 and 0.86 and showed no significant differences between the two groups. Hierarchical AMOVA and principal component analysis revealed very high genetic population admixture and negligible differentiation between indigenous and restored sites (F_CT = 0.002). Moreover, differentiation between groups was caused by only one outlier population, where inbreeding effects are presumed. We therefore conclude that the introduction of nonlocal seed provenances in the course of landscape restoration did not jeopardize regional species persistence by contributing to inbreeding or outbreeding depressions, or any measurable adverse population genetic effect. On the basis of these results, we see no obvious objections to the current practice to use the 10‐fold cheaper, nonlocal seed material of D. carota for restoration projects.     

Association between rs3088440 (G > A) polymorphism at 9p21.3 locus with the occurrence and severity of coronary artery disease in an Iranian population

Molecular Biology Reports - Several genome-wide association studies showed that a series of genetic variants located at the chromosome 9p21 locus are strongly associated with coronary artery...     

Impact of land use on plant biodiversity and measures for biodiversity conservation in the Loess Plateau in China – a case study in a hilly-gully region of the Northern Loess Plateau

The Loess Plateau is a special natural–cultural unit in northern China. Intensive land use in the past has had, and forestation and grass planting at present will have inevitable impacts on plant biodiversity in the Loess Plateau. Based on the analysis of floristic features within three sampling sites with different land use practices and analysis of species richness among different land use types, we discuss impacts of land use on species richness and floristic features in the Northern Loess Plateau. The results drawn from this case study are as follows: (1) It appears that forestation and grass planting have had a positive influence on the local species diversity, but they have contributed little to the native vegetation in terms of conserving its floristic features. (2) Caragana intermedia shrubland, Pinus tabulaeformis forestland, and natural grassland have made important contributions to supporting indigenous species and maintaining local plant biodiversity. (3) There is a significant positive correlation between land use diversity and species richness. These results imply that practicing biodiversity conservation in situ is feasible and the suitable choice for the Loess Plateau. Concrete measures for biodiversity conservation in the area can include setting up small nature reserves and diversifying land use patterns to maintain as much habitat as possible for native vegetation. The artificial Hippophae rhamnoides shrubland should not be further promoted, considering its negative influence on biodiversity conservation.     

Symbionts in excess? No correlation between symbiont density and the ability of mealybug hosts to exploit plant species or tolerate insecticide stress

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An MspI polymorphism in the X-specific region proximal to the pseudoautosomal boundary. A new example of a unique “African” marker?

A polymorphic MspI site was located in the X-specific region proximal to the pseudoautosomal boundary. Two alleles defined by the absence or the presence of the MspI site were detected by the polymerase chain reaction (PCR) in a sample of Bantu-speaking individuals from Cameroon. No variation for this site was observed in a population sample from Italy.     

An evaluation of the genetic connectivity and temporal stability of the blue and red shrimp Aristeus antennatus: a case study of spawning females’ grounds in the Western Mediterranean Sea

Hydrobiologia - The blue and red shrimp Aristeus antennatus has been intensively exploited by trawling fishery in the Western Mediterranean Sea. Implementation of an adequate management plan needs...     

Gastric duplication cyst in an adult with autoimmune hemolytic anemia: a case report and review of the literature

Background

Gastric duplication cysts are uncommon congenital anomalies found primarily in children and rarely seen in the adult population. Accurate diagnosis of cysts before resection is difficult even using the most advanced imaging techniques.

Case presentation

In this report, we describe a 28-year-old Moroccan patient with a history of autoimmune hemolytic anemia who presented with an asymptomatic abdominal cystic mass detected during abdominal computed tomography performed before splenectomy. Magnetic resonance imaging performed for accurate characterization showed a high-signal-intensity cystic mass on T2-weighted images, located between the patient’s stomach and spleen. The patient underwent a complete cyst resection during exploratory laparotomy. The histological examination showed a cyst lined by three different epithelia with bundles of smooth muscle, which suggested a gastric duplication cyst.

Conclusions

We report a case of gastric cyst duplication in an adult with autoimmune hemolytic anemia, and we discuss this rare association, radiological findings, and the unique histological findings of this case.

     

Being a generalist herbivore in a diverse world: how do diets from different grasslands influence food plant selection and fitness of the grasshopper Chorthippus parallelus?

1. Generalist insect herbivores occupy a variety of habitats that differ in food plant composition. Dietary mixing has been proposed as a possibility for generalists to overcome nutritional deficiencies of single plant species, but only a few studies have investigated herbivore feeding and fitness for diets that resemble natural scenarios. We studied feeding behaviour, survival, and reproduction of the generalist grasshopper Chorthippus parallelus raised on food plants of four typical habitats. 2. Grasshopper diet consisted of grasses (92.5%), legumes (6.7%) and, in small quantities, other forbs (0.8%). Diet selection differed between the four food plant mixtures, and depended on grasshopper sex and developmental stage. There was no correlation between the relative abundance of plant species in the field and the fraction of these species in the grasshopper diet. 3. Grasshoppers survived on average for 40.4 ± 1.0 days before maturity, grew 106.8 mg until maturity moult, and females laid 4.1 ± 0.4 egg pods, each of which contained 8.5 ± 0.4 eggs. However, despite the differences in feeding behaviour, grasshopper fitness was the same in all of the four food plant mixtures. While the digestibility of ingested food was similar in the four different treatments, indices indicated differences in the conversion efficiency to body mass. 4. Our results show that C. parallelus is a plastic feeder with no fixed preferences in diet composition. The results emphasise that generalist herbivores can counteract putative quality deficiencies of single food plants by selective dietary mixing.