Echiniscus testudo (Doyère, 1840) in New Zealand: anthropogenic dispersal or evidence for the ‘Everything is Everywhere’ hypothesis?

Many species of microscopic invertebrates, such as tardigrades or rotifers, have been traditionally regarded as cosmopolitan. This conviction was based on classical taxonomic observations of very similar phenotypes across the globe and hypothetical abilities of micrometazoans for large-scale dispersal with air and water currents. However, several recent studies showed that micrometazoan species may have restricted geographic ranges, suggesting that microscopic size is not the only determinant of dispersal. Here, we describe the first Australasian record of Echiniscus testudo, a heterotardigrade originally described from the Holarctic. Morphological and genetic analyses gave congruent conclusions and confirmed that European and New Zealand populations represent a single species. Importantly, however, without broader sampling in primeval localities, it is not possible to test whether the New Zealand record of E. testudo is a result of natural dispersal or whether the species was brought to Australasia by humans.     

Fast and Forceful Refolding of Stretched α-Helical Solenoid Proteins

Anfinsen's thermodynamic hypothesis implies that proteins can encode for stretching through reversible loss of structure. However, large in vitro extensions of proteins that occur through a progressive unfolding of their domains typically dissipate a significant amount of energy, and therefore are not thermodynamically reversible. Some coiled-coil proteins have been found to stretch nearly reversibly, although their extension is typically limited to 2.5 times their folded length. Here, we report investigations on the mechanical properties of individual molecules of ankyrin-R, β-catenin, and clathrin, which are representative examples of over 800 predicted human proteins composed of tightly packed α-helical repeats (termed ANK, ARM, or HEAT repeats, respectively) that form spiral-shaped protein domains. Using atomic force spectroscopy, we find that these polypeptides possess unprecedented stretch ratios on the order of 10-15, exceeding that of other proteins studied so far, and their extension and relaxation occurs with minimal energy dissipation. Their sequence-encoded elasticity is governed by stepwise unfolding of small repeats, which upon relaxation of the stretching force rapidly and forcefully refold, minimizing the hysteresis between the stretching and relaxing parts of the cycle. Thus, we identify a new class of proteins that behave as highly reversible nanosprings that have the potential to function as mechanosensors in cells and as building blocks in springy nanostructures. Our physical view of the protein component of cells as being comprised of predominantly inextensible structural elements under tension may need revision to incorporate springs.     

Numerical simulation for a neurotransmitter transport model in the axon terminal of a presynaptic neuron

Neurotransmitters in the terminal bouton of a presynaptic neuron are stored in vesicles, which diffuse in the cytoplasm and, after a stimulation signal is received, fuse with the membrane and release its contents into the synaptic cleft. It is commonly assumed that vesicles belong to three pools whose content is gradually exploited during the stimulation. This article presents a model that relies on the assumption that the release ability is associated with the vesicle location in the bouton. As a modeling tool, partial differential equations are chosen as they allow one to express the continuous dependence of the unknown vesicle concentration on both the time and space variables. The model represents the synthesis, concentration-gradient-driven diffusion, and accumulation of vesicles as well as the release of neuroactive substances into the cleft. An initial and boundary value problem is numerically solved using the finite element method (FEM) and the simulation results are presented and discussed. Simulations were run for various assumptions concerning the parameters that govern the synthesis and diffusion processes. The obtained results are shown to be consistent with those obtained for a compartment model based on ordinary differential equations. Such studies can be helpful in gaining a deeper understanding of synaptic processes including physiological pathologies. Furthermore, such mathematical models can be useful for estimating the biological parameters that are included in a model and are hard or impossible to measure directly.     

Flow Cytometry,HPLC-RP,and metAFLP Analyses to Assess Genetic Variability in Somatic Embryo-Derived Plantlets of <Emphasis Type="BoldItalic">Gentiana pannonica</Emphasis> Scop

Cytometric and molecular techniques were used to verify genetic uniformity among somatic embryo-derived plantlets of Gentiana pannonica Scop. Cytometric analysis of regenerants revealed absence of chromosomal changes and alterations in ploidy. However, reverse phase high pressure liquid chromatography detected higher levels of methylation in regenerated plants than those of control plants. These changes were further investigated using a quantitative molecular marker-based approach. This revealed that numerous tissue culture-induced variations, ∼3% (epi)mutations, were observed, including sequence variation and changes in methylation patterns. Moreover, complex patterns of variation, including combinations of genetic and epigenetic changes, were relatively high (ca. 9%). Overall, tissue culture-induced variation reached 16%; while, demethylation was lower than de novo methylation in heterozygotic material and similar in all regenerated plantlets.     

Multinuclear magnetic resonance, electrospray ionization-mass spectroscopy, and parametric method 5 studies of a new derivative of gossypol with 2-thiophenecarbohydrazide as well as its complexes with LI+, Na+, K+, RB+, and Cs+ cations

A new derivative of racemic gossypol with 2-thiophenecarbohydrazide (GHHT) and its complexes with monovalent cations have been synthesized and studied by electrospray ionization-mass spectroscopy (ESI-MS), multinuclear nuclear magnetic resonance (NMR), as well as by the Parametric Method 5 (PM5) methods. It is demonstrated that GHHT forms stable complexes of 1:1 stoichiometry with monovalent metal cations. The structures of the complexes are stabilized by three types of intramolecular hydrogen bonds. The spectroscopic methods have provided clear evidence that GHHT and its complexes exist in the DMSO-d6 solution in the N-imine-N-imine tautomeric forms. The structures of the GHHT and its complexes with Li+, Na+, K+, Rb+, and Cs+ cations are visualized and discussed in detail.     

Polyamines in yellow lupin (<Emphasis Type="Italic">Lupinus luteus</Emphasis> L.) tolerance to soil drought

Polyamines (PAs) are related to many physiological processes, including soil drought stress. Two yellow lupin ‘Morocco 4’ (drought tolerant) and ‘Taper’ (drought sensitive) were exposed to soil drought for 2 weeks. The half of the examined plants were additionally sprayed with a solution of polyamine biosynthesis inhibitor—dl-α-difluoromethylarginine (DFMA). Yellow lupin leaves showed a 19% increase and seeds a 54% decrease in the total PA contents. The seeds contained fourfold less PAs than the leaves under drought conditions. The highest amount of spermidine and lack of agmatine were found in the leaves, while in the seeds the highest content of spermine and the presence of agmatine was confirmed. The use of DFMA under drought conditions decreased the content of spermine in ‘Morocco 4’ and ‘Taper’ (41 and 19%, respectively) and spermidine in ‘Taper’ (by 13%), as well as reduced two out of three of the yield components. More tolerant ‘Morocco 4’, after DFMA treatment was characterized by a higher spermidine and spermine content and a smaller decrease in yield components compared to the less tolerant ‘Taper’. Simultaneously subjecting plants to soil drought and DFMA treatment caused in ‘Morocco 4’ a decline in the number of pods and seeds per plant and seeds dry weight per plant (64, 50 and 54%, respectively), while in ‘Taper’ a reduction of the number of pods per plant and seeds per pod (32 and 27%, respectively) was observed. These results confirm that PAs are involved in yellow lupin tolerance and may play a protective function under soil drought conditions.     

XbaI and PvuII Polymorphisms of Estrogen Receptor 1 Gene in Females with Idiopathic Scoliosis: No Association with Occurrence or Clinical Form

Introduction

XbaI single nucleotide polymorphism (SNP) (A/G rs934099) in estrogen receptor 1 gene (ESR1) was described to be associated with curve severity in Japanese idiopathic scoliosis (IS) patients and in Chinese patients with both curve severity and predisposition to IS. PvuII SNP (C/T rs2234693) of ESR1 was described to be associated with the occurrence of IS in the Chinese population; however, two replication studies did not confirm the findings. The ESR1 SNPs have never been studied in Caucasian IS patients.

Methods

Case-control study. 287 females with IS underwent clinical, radiological and genetic examinations. The patients were divided into three groups according to curve progression velocity: non-progressive IS, slowly progressive IS (progression <1° per month), and rapidly progressive IS (progression ≥1° per month). The radiological maximum Cobb angle was measured and surgery rate established. A control group consisted of 182 healthy females.

Results

All results followed Hardy-Weinberg equilibrium. In the case-control study, genotype frequency in the patients did not differ for the XbaI (AA = 33.5%, AG = 49.1%, GG = 17.4%), nor for the PvuII (TT = 26.8%, TC = 50.2%, CC = 23.0%) comparing to controls (AA = 33.5%, AG = 50.5%, GG = 15.9%) and (TT = 23.1%, TC = 51.1%, CC = 25.8%), respectively, p = 0.3685, p = 0.6046. The haplotype frequency for the patients (AT = 47.1%, GC = 39.2%, AC = 8.9%, GT = 2.8%) did not differ from the controls (AT = 44.8%, GC = 37.4%, AC = 14.0%, GT = 3.8%), p = 0.0645. No difference was found either in XbaI (p = 0.8671) or PvuII (p = 0.3601) allele distribution between the patients and the controls. In the case study, there was no significant difference in genotype frequency for the non-progressive, slowly progressive, and rapidly progressive scoliosis. No difference was found in genotype or haplotype distribution for the mean maximum Cobb angle or the surgery rate.

Conclusions

No association was found between ESR1 XbaI or ESR1 PvuII SNP and idiopathic scoliosis in Caucasian females. None of the previously reported associations could be confirmed, regarding curve severity, progression or operation rate.