Paleo-Balkan and Slavic Contributions to the Genetic Pool of Moldavians: Insights from the Y Chromosome

Moldova has a rich historical and cultural heritage, which may be reflected in the current genetic makeup of its population. To date, no comprehensive studies exist about the population genetic structure of modern Moldavians. To bridge this gap with respect to paternal lineages, we analyzed 37 binary and 17 multiallelic (STRs) polymorphisms on the non-recombining portion of the Y chromosome in 125 Moldavian males. In addition, 53 Ukrainians from eastern Moldova and 54 Romanians from the neighboring eastern Romania were typed using the same set of markers. In Moldavians, 19 Y chromosome haplogroups were identified, the most common being I-M423 (20.8%), R-M17* (17.6%), R-M458 (12.8%), E-v13 (8.8%), R-M269* and R-M412* (both 7.2%). In Romanians, 14 haplogroups were found including I-M423 (40.7%), R-M17* (16.7%), R-M405 (7.4%), E-v13 and R-M412* (both 5.6%). In Ukrainians, 13 haplogroups were identified including R-M17 (34.0%), I-M423 (20.8%), R-M269* (9.4%), N-M178, R-M458 and R-M73 (each 5.7%). Our results show that a significant majority of the Moldavian paternal gene pool belongs to eastern/central European and Balkan/eastern Mediterranean Y lineages. Phylogenetic and AMOVA analyses based on Y-STR loci also revealed that Moldavians are close to both eastern/central European and Balkan-Carpathian populations. The data correlate well with historical accounts and geographical location of the region and thus allow to hypothesize that extant Moldavian paternal genetic lineages arose from extensive recent admixture between genetically autochthonous populations of the Balkan-Carpathian zone and neighboring Slavic groups.     

Mathematical model for the ecosystem response of Lake Ladoga to phosphorus loading

The ecosystem response model described in this paper combines an ecosystem model and a three-dimensional circulation model of Lake Ladoga developed earlier by the authors. The ecosystem model describes the process of Lake Ladoga eutrophication, and its biological submodel describes changes in the phyto- and zooplankton. In the earlier model version, lake circulation was determined using a two-dimensional hydrodynamical model which was not completely adequate. The present model allows calculation of the distributions of phyto- and zooplankton and mineral phosphorus and nitrogen. One of its main advantages is that reliable computations of the ecosystem dynamics over an extended period of time are possible. The response of the ecosystem to different levels of phosphorus pollution loading and to weather conditions is studied.     

Comparison of the Wild-Type Obligate Methylotrophic Bacterium Methylophilus quaylei and its Isogenic Streptomycin-Resistant Mutant via Metal Nanoparticle Generation

Biological Trace Element Research - Metal nanoparticles synthesized by green methods with the use of microorganisms are currently one of the most closely studied types of nanomaterials. It has...     

Female gametophytic mutants of Arabidopsis thaliana identified in a gene trap insertional mutagenesis screen

In plants, the male and female gametophytes represent the haploid generation that alternates with the diploid sporophytic generation. Male and female gametophytes develop from haploid micro- and megaspores, respectively. In flowering plants (angiosperms), the spores themselves arise from the sporophyte through meiotic divisions of sporogenous cells in the reproductive organs of the flower. Male and female gametophytes contain two pairs of gametes that participate in double fertilization, a distinctive feature of angiosperms. In this paper, we describe the employment of a transposon-based gene trap system to identify mutations affecting the gametophytic phase of the plant life cycle. Mutants affecting female gametogenesis were identified in a two-step screen for (i) reduced fertility (seed abortion or undeveloped ovules) and (ii) segregation ratio distortion. Non-functional female gametophytes do not initiate seed development, leading to semi-sterility such that causal or linked alleles are transmitted at reduced frequency to the progeny (non-Mendelian segregation). From a population of 2,511 transposants, we identified 54 lines with reduced seed set (2%). Examination of their distorted segregation ratios and seed phenotypes led to the isolation of 12 gametophytic mutants, six of which are described herein. Chromosomal sequences flanking the transposon insertions were identified and physically mapped onto the genome sequence of Arabidopsis thaliana. Surprisingly, the insertion sites were often associated with chromosomal rearrangements, making it difficult to assign the mutant phenotypes to a specific gene. The mutants were classified according to the process affected at the time of arrest, i.e. showing mitotic, karyogamic, maternal or degenerative phenotypes.     

Mechanism of low-density lipoprotein oxidation by hemoglobin-derived iron

Excellular hemoglobin is an extremely active oxidant of low-density lipoproteins (LDL), a phenomenon explained so far by different mechanisms. In this study, we analyzed the mechanism of met-hemoglobin oxidability by comparing its mode of operation with other hemoproteins, met-myoglobin and horseradish peroxidase (HRP) or with free hemin. The kinetics of met-hemoglobin activity toward LDL lipids and protein differed from that of met-myoglobin and HRP, both quantitatively and qualitatively. Those differences were further clarified by analyzing heme transfer from the above-mentioned hemoproteins to LDL. It appeared that met-hemoglobin transferred most of its hemin to LDL, and the presence of H(2)O(2) accelerated the process. In contrast, met-myoglobin partially released hemin, but only in the presence of H(2)O(2), while HRP could not transfer heme at all. The minor amount of hemin transferred from met-myoglobin to LDL sufficed to trigger ApoB oxidation, forming covalent aggregates via inter-bityrosines. This indicated that heme bound to high affinity site(s) is responsible for oxidation. LDL components providing the sites were analyzed by binding heme-CO monomers to LDL. Soret spectra revealed that the high affinity site of monomeric hemin is located on the LDL protein, ApoB. The complex heme-CO-ApoB underwent instantaneous oxidation to hemin-ApoB, and the bound hemin then slowly disintegrated in conjunction with LDL oxidation. Hemopexin prevented LDL oxidation by trapping hemoprotein transferable heme. We concluded that met-hemoglobin exerts its oxidative activity on LDL via transfer of heme, which serves as a vehicle for iron insertion into the LDL protein, leading to formation of atherogenic LDL aggregates.     

Preconcentration of organic solutes in urine by bubble bursting

Introduction

The chemical sensitivity of urine metabolomics analysis is greatly compromised due to the large amounts of inorganic salts in urine (NaCl, KCl), which are detrimental to analytical instrumentation, e.g. chromatographic columns or mass spectrometers. Traditional desalting approaches applied to urine pretreatment suffer from the chemical losses, which reduce the information depth of analysis.

Objectives

We aimed to test a simple approach for the simultaneous preconcentration and desalting of organic solutes in urine based on the collection of induced bursting bubble aerosols above the surface of urine samples.

Method

Bursting bubbles were generated at ambient conditions by feeding gas through an air diffuser at the bottom of diluted (200 times in ultrapure water) urine solution (50–500 mL). Collected aerosols were analyzed by the direct-infusion electrospray ionization mass spectrometry (ESI–MS).

Results

The simultaneous preconcentration (ca. 6–12 fold) and desalting (ca. six–tenfold) of organic solutes in urine was achieved by the bursting bubble sample pretreatment, which allowed ca. three-times higher number of identified urine metabolites by high-resolution MS analysis. No chemical losses due to bubbling were observed. The increased degree of MS data clustering was demonstrated on the principal component analysis of data sets from the urine of healthy people and from the urine people with renal insufficiency. At least ten times higher sensitivity of trace drug detection in urine was demonstrated for clenbuterol and salbutamol.

Conclusion

Our results indicate the high versatility of bubble bursting as a simple pretreatment approach to enhance the chemical depth and sensitivity of urine analysis. The approach could be attractive for personalized medicine as well as for the diagnostics of renal disorders of different etiology (diabetic nephropathy, chronic renal failure, transplant-associated complications, oncological disorders).

Graphical Abstract

Urine desalting and preconcentration in bursting bubbles.

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Effects of Spontaneous Bilayer Curvature on Influenza Virus–mediated Fusion Pores

Cells expressing the hemagglutinin protein of influenza virus were fused to planar bilayer membranes containing the fluorescent lipid probes octadecylrhodamine (R18) or indocarbocyanine (DiI) to investigate whether spontaneous curvature of each monolayer of a target membrane affects the growth of fusion pores. R18 and DiI lowered the transition temperatures for formation of an inverted hexagonal phase, indicating that these probes facilitate the formation of negative curvature structures. The probes are known to translocate from one monolayer of a bilayer membrane to the other in a voltage-dependent manner. The spontaneous curvature of the cis monolayer (facing the cells) or the trans monolayer could therefore be made more negative through control of the polarity of voltage across the planar membrane. Electrical admittance measurements showed that the open times of flickering fusion pores were shorter when probes were in trans monolayers and longer when in cis monolayers compared with times when probe was symmetrically distributed. Open times were the same for probe symmetrically distributed as when probes were not present. Thus, open times were a function of the asymmetry of the spontaneous curvature between the trans and cis monolayers. Enriching the cis monolayer with a negative curvature probe reduced the probability that a small pore would fully enlarge, whereas enriching the trans monolayer promoted enlargement. Lysophosphatidylcholine has positive spontaneous curvature and does not translocate. When lysophosphatidylcholine was placed in trans leaflets of planar membranes, closing of fusion pores was rare. The effects of the negative and positive spontaneous curvature probes do not support the hypothesis that a flickering pore closes from an open state within a hemifusion diaphragm (essentially a “flat” structure). Rather, such effects support the hypothesis that the membrane surrounding the open pore forms a three-dimensional hourglass shape from which the pore flickers shut.     

Pharmacological properties and predicted binding mode of arylmethylene quinuclidine-like derivatives at the α3β4 nicotinic acetylcholine receptor (nAChR)

We have carried out a pharmacological evaluation of arylmethylene quinuclidine derivatives interactions with human α3β4 nAChRs subtype, using cell-based receptor binding, calcium-influx, electrophysiological patch-clamp assays and molecular modeling techniques. We have found that the compounds bind competitively to the α3β4 receptor with micromolar affinities and some of the compounds behave as non-competitive antagonists (compounds 1, 2 and 3), displaying submicromolar IC₅₀ values. These evidences suggest a mixed mode of action for these compounds, having interactions at the orthosteric site and more pronounced interactions at an allosteric site to block agonist effects. One of the compounds, 1-benzyl-3-(diphenylmethylene)-1-azoniabicyclo[2.2.2]octane chloride (compound 3), exhibited poorly reversible use-dependent block of α3β4 channels. We also found that removal of a phenyl group from compound 1 confers a partial agonism to the derived analog (compound 6). Introducing a hydrogen-bond acceptor into the 3-benzylidene quinuclidine derivative (compound 7) increases agonism potency at the α3β4 receptor subtype. Docking into the orthosteric binding site of a α3β4 protein structure derived by comparative modeling accurately predicted the experimentally-observed trend in binding affinity. Results supported the notion that binding requires a hydrogen bond formation between the ligand basic nitrogen and the backbone carbonyl oxygen atom of the conserved Trp-149.