Dissecting the molecular architecture and origin of Bayash Romani patrilineages: genetic influences from South-Asia and the Balkans

The Bayash are a branch of Romanian speaking Roma living dispersedly in Central, Eastern, and Southeastern Europe. To better understand the molecular architecture and origin of the Croatian Bayash paternal gene pool, 151 Bayash Y chromosomes were analyzed for 16 SNPs and 17 STRs and compared with European Romani and non-Romani majority populations from Europe, Turkey, and South Asia. Two main layers of Bayash paternal gene pool were identified: ancestral (Indian) and recent (European). The reduced diversity and expansion signals of H1a patrilineages imply descent from closely related paternal ancestors who could have settled in the Indian subcontinent, possibly as early as between the eighth and tenth centuries AD. The recent layer of the Bayash paternal pool is dominated by a specific subset of E1b1b1a lineages that are not found in the Balkan majority populations. At least two private mutational events occurred in the Bayash during their migrations from the southern Balkans toward Romania. Additional admixture, evident in the low frequencies of typical European haplogroups, J2, R1a, I1, R1b1b2, G, and I2a, took place primarily during the early Bayash settlement in the Balkans and the Romani bondage in Romania. Our results indicate two phenomena in the Bayash and analyzed Roma: a significant preservation of ancestral H1a haplotypes as a result of considerable, but variable level of endogamy and isolation and differential distribution of less frequent, but typical European lineages due to different patterns of the early demographic history in Europe marked by differential admixture and genetic drift.     

Trehalose synthase of Mycobacterium smegmatis: purification, cloning, expression, and properties of the enzyme.

Trehalose synthase (TreS) catalyzes the reversible interconversion of trehalose (glucosyl-alpha,alpha-1,1-glucose) and maltose (glucosyl-alpha1-4-glucose). TreS was purified from the cytosol of Mycobacterium smegmatis to give a single protein band on SDS gels with a molecular mass of approximately 68 kDa. However, active enzyme exhibited a molecular mass of approximately 390 kDa by gel filtration suggesting that TreS is a hexamer of six identical subunits. Based on amino acid compositions of several peptides, the treS gene was identified in the M. smegmatis genome sequence, and was cloned and expressed in active form in Escherichia coli. The recombinant protein was synthesized with a (His)(6) tag at the amino terminus. The interconversion of trehalose and maltose by the purified TreS was studied at various concentrations of maltose or trehalose. At a maltose concentration of 0.5 mm, an equilibrium mixture containing equal amounts of trehalose and maltose (42-45% of each) was reached during an incubation of about 6 h, whereas at 2 mm maltose, it took about 22 h to reach the same equilibrium. However, when trehalose was the substrate at either 0.5 or 2 mm, only about 30% of the trehalose was converted to maltose in >or= 12 h, indicating that maltose is the preferred substrate. These incubations also produced up to 8-10% free glucose. The K(m) for maltose was approximately 10 mm, whereas for trehalose it was approximately 90 mm. While beta,beta-trehalose, isomaltose (alpha1,6-glucose disaccharide), kojibiose (alpha1,2) or cellobiose (beta1,4) were not substrates for TreS, nigerose (alpha1,3-glucose disaccharide) and alpha,beta-trehalose were utilized at 20 and 15%, respectively, as compared to maltose. The enzyme has a pH optimum of about 7 and is inhibited in a competitive manner by Tris buffer. [(3)H]Trehalose is converted to [(3)H]maltose even in the presence of a 100-fold or more excess of unlabeled maltose, and [(14)C]maltose produces [(14)C]trehalose in excess unlabeled trehalose, suggesting the possibility of separate binding sites for maltose and trehalose. The catalytic mechanism may involve scission of the incoming disaccharide and transfer of a glucose to an enzyme-bound glucose, as [(3)H]glucose incubated with TreS and either unlabeled maltose or trehalose results in formation of [(3)H]disaccharide. TreS also catalyzes production of a glucosamine disaccharide from maltose and glucosamine, suggesting that this enzyme may be valuable in carbohydrate synthetic chemistry.     

Male moth songs tempt females to accept mating: the role of acoustic and pheromonal communication in the reproductive behaviour of Aphomia sociella

Background

Members of the subfamily Galleriinae have adapted to different selective environmental pressures by devising a unique mating process. Galleriinae males initiate mating by attracting females with either chemical or acoustic signals (or a combination of both modalities). Six compounds considered candidates for the sex pheromone have recently been identified in the wing gland extracts of Aphomia sociella males. Prior to the present study, acoustic communication had not been investigated. Signals mediating female attraction were likewise unknown.

Methodology/Principal Findings

Observations of A. sociella mating behaviour and recordings of male acoustic signals confirmed that males initiate the mating process. During calling behaviour (stationary wing fanning and pheromone release), males disperse pheromone from their wing glands. When a female approaches, males cease calling and begin to produce ultrasonic songs as part of the courtship behaviour. Replaying of recorded courting songs to virgin females and a comparison of the mating efficiency of intact males with males lacking tegullae proved that male ultrasonic signals stimulate females to accept mating. Greenhouse experiments with isolated pheromone glands confirmed that the male sex pheromone mediates long-range female attraction.

Conclusion/Significance

Female attraction in A. sociella is chemically mediated, but ultrasonic communication is also employed during courtship. Male ultrasonic songs stimulate female sexual display and significantly affect mating efficiency. Considerable inter-individual differences in song structure exist. These could play a role in female mate selection provided that the female''s ear is able to discern them. The A. sociella mating strategy described above is unique within the subfamily Galleriinae.     

Immunomodulatory effect of selenosemicarbazides and selenium inorganic compounds, distribution in organs after selenium supplementation

Antioxidant properties of selenium producing a protective barrier against free radicals play an important role in numerous metabolic and immunologic processes associated with oxidation- reduction reactions which take place during intracellular digestion of phagocyted bacteria. The aim of our study was to examine the properties of an organic compound of selenium, 4-(o-tolilo)- selenosemicarbazide of p-chlorobenzoic acid in terms of its retention in organs, effect on erythropoesis and phagocytic abilities of neutrophiles as well as antioxidant properties in neutrophiles tested with NBT test. This compound as well as inorganic sodium selenate was given to Swiss mice at the dose of 10^–3 g Se/kg for the period of 10 days. The concentrations of selenium in livers of mice treated with sodium selenate and selenosemicarbazide were found to be higher than in controls (18,7 g lg^–1 and 23.2 g lg^–1 vs. 12 g lg^–1, respectively). Analysis of blood cells count has shown a significant decrease in neutrophile levels in both groups treated with selenium. The influence of selenium compounds on phagocytosis and especially NBT test has been determined (3.8% of positive cells in the controls vs. 2.2% and 0.9% in the groups treated with sodium selenate and selenosemicarbazide, respectively). Our preliminary investigations suggest that selenosemicarbazides are biologically active compounds and can modify neutrophile functions.     

A mutation in the herbicide target site acetohydroxyacid synthase produces morphological and structural alterations and reduces fitness in Amaranthus powellii

We investigated the effect of a herbicide resistance-conferring mutation on fitness in Amaranthus powellii. Morphological and histological observations were made. Growth and leaf appearance were recorded for six resistant and six susceptible populations. The competitiveness of a susceptible population was compared with that of a resistant population using a replacement series experiment. Leaves of the resistant plants were distorted and much smaller than those of susceptible plants. Additionally, they exhibited an abnormal morphological and structural pattern consisting of a mosaic of heterogeneous areas in the same leaf blade. The roots and stems had similar structures in susceptible and resistant plants, but the former were up to four times more developed. The resistant plants were slower to develop and produced 67% less biomass and 58% lower leaf area than susceptible plants. Under competitive conditions, one susceptible population outperformed one resistant population by 7-15 times. The Trp(574)Leu acetohydroxyacid synthase (AHAS) mutation appears to have considerable pleiotropic effects on the early growth and development of the plants which, in competitive conditions, greatly reduce fitness.     

Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

Photoinhibition of white clover seed germination at low water potential

Photosensitivity of germination of white clover ( Trifolium repens L. cv. Podkowa) seeds was studied under water deficit (low water potential) conditions at 25°C. The seeds showed negative photoblastism, which was most pronounced at -0.03 MPa polyethylene glycol solution. Inhibition was observed at two different wavelength bands with maxima at 660 nm (R) and around 730 nm (FR). Red light acted identically to white light (maximum inhibition ca 50%). The effect of far-red illumination was less inhibitory (20–30%). The photoresponse required long illuminations (3 h exposures); saturation level was at 0.1 W m⁻², independently of the light quality. White clover seed germination showed no reversibility of the effects of R and FR light. Prolonged illumination with R and FR increased the inhibition, and intermittent illumination had a higher effect than a continuous one. It was concluded that the photoinhibition of germination of seeds of Trifolium repens involves a reaction dependent on the rate of phytochrome interconversion, a property that is characteristic for the high irradiance reaction.     

Changes in the thymus of peripubertal rats induced by centrally applied somatostatin-28

The aim of this study was to investigate the effects of centrally applied somatostatin-28 on morphometric characteristics of the thymus, the thymocyte subpopulations, as well as, on apoptosis and phases of cell cycle in thymocytes. For this purpose, peripubertal male rats were cannulated intracerebroventriculary and treated with repeated, nanomolar concentrations of somatostatin-28 (experimental group) or saline (control group). Animals were sacrificed and their thymuses were used for the analysis of thymocyte subpopulations, cell cycle and apoptosis by flow cytometry and for the evaluation of morphometric parameters by stereological analysis. Our results showed that somatostatin-28 caused decrease of the thymic mass and volume, as well as total thymocytes number. Stereological analysis revealed volume decrease of thymic cortex and medulla accompanied with cellularity decrease. Somatostatin in the deeper cortex decreased the number of thymocytes, per volume unit, while in outer cortex raised their number. A significant increase in the percentage of double-negative and both single-positive thymocyte subpopulations, in parallel with a diminished percentage of double-positive cells was found. The cellularity of double-positive and single-positive thymocyte subpopulations was decreased. Somatostatin-28 treatment augmented the percentage of apoptotic cells, while the percentage of the cells represented in phases of cell cycle was reduced. These results suggest that somatostatin-28 induce thymus hypotrophy as result of decreasing cortex and medulla volume and cellularity. Changes in the percentage and cellularity of thymocyte subpopulations and numerical density of thymocytes in outer and deeper cortex, indicate that somatostatin-28 evoked disturbance in transition of double-negative to double-positive thymocytes.     

Cadmium regulation by Lasius niger: A contribution to understanding high metal levels in ants

Ants (Formicinae, Hymenoptera) are considered efficient accumulators of Zn and Cd. In this study the relationship between Cd concentrations in soil and in Lasius niger workers was assessed for 20 colonies located along a gradient of Cd pollution. As soil Cd concentration increased from 1 to 8 mg/kg, ant body Cd concentration increased rapidly to about 40 mg/kg, and remained stable at this level, through a progressive increase of soil Cd concentration from 8 to 21 mg/kg. The phase of rapid increase confirms the high ability of L. niger for Cd accumulation, while the stabilization of Cd body concentration indicates either increasing elimination rate or decreasing rate of uptake. Therefore it can be concluded that Lasius niger has a high ability to accumulate Cd, but simultaneously an ability for Cd regulation was detected.