Synergetic Effects of K,Ca, Cu and Zn in Human Semen in Relation to Parameters Indicative of Spontaneous Hyperactivation of Spermatozoa

We have observed that sperm quality parameters indicative of spermatozoa hyperactivation such are lower “linearity” and “straightness”, and as showed by this research “elongation”, were more pronounced in patients with normal spermiogram compared to the group of men with reduced sperm motility who were undergoing routine in vitro fertilisation. The research encompassed 97 men diagnosed with normozoospermia (n = 20), asthenozoospermia (n = 54) and oligoasthenozoospermia (n = 23). The findings indicate that sperm quality of patients with normal spermiogram diagnosed according to WHO criteria, may be compromised by showing premature spontaneous hyperactivation which can decrease the chances of natural conception. We assessed synergistic effects of multiple chemical elements in ejaculated semen to find if premature spontaneous hyperactivation of spermatozoa can be a sign of imbalanced semen composition especially of elements K, Ca, Cu and Zn. Human semen samples showing low or high baseline status of chemical elements concentrations were found in samples from all three diagnostic groups. However, correlation of K/Ca and Cu/Zn ratios, taking into account samples from all three groups of men, were negative at statistical significance level p = 0.01. We tested if the negative correlation between K/Ca and Cu/Zn ratio works for greater number of semen samples. We found the negative correlation to be valid for 175 semen samples at statistical significance of p = 0.00002. The ratio of K/Ca and Cu/Zn, i.e. increased concentrations of K and Zn in comparison to concentrations of Ca and Cu, were associated with a decrease of “straightness” in the group of men with normal spermiogram and pronounced spontaneous hyperactivation of spermatozoa, implying that these elements act in synergy and that the balance of elements and not their absolute concentrations plays the major role in premature spermatozoa hyperactivation in ejaculated semen.     

Three-dimensional soft tissue preservation revealed in the skin of a non-avian dinosaur

The most commonly preserved soft tissues associated with ornithischian dinosaurs are skin remains. The apparent resistance of hadrosaur skin to decay, and its abundance in the fossil record relative to that of other tetrapods, has been attributed to factors such as thickness and composition. Here we report additional intrinsic factors within hadrosaur skin: 3D-preserved eumelanin-bearing bodies, dermal cells and blood vessel fragments in an organic matrix composed of protein fossilization products. The skin is much thinner than that of living mammals of similar size. It is likely that the preservation of hadrosaur skin is related to the arrangement of the layers composing it.     

Integrity of White Matter is Compromised in Mice with Hyaluronan Deficiency

Neurochemical Research - Brain white matter is the means of efficient signal propagation in brain and its dysfunction is associated with many neurological disorders. We studied the effect of...     

How DNA Polymerase X Preferentially Accommodates Incoming dATP Opposite 8-Oxoguanine on the Template

The modified base 8-oxo-7,8-dihydro-2′-deoxyguanosine (oxoG) is a common DNA adduct produced by the oxidation of DNA by reactive oxygen species. Kinetic data reveal that DNA polymerase X (pol X) from the African swine fever virus incorporates adenine (dATP) opposite to oxoG with higher efficiency than the non-damaged G:C basepair. To help interpret the kinetic data, we perform molecular dynamics simulations of pol X/DNA complexes, in which the template base opposite to the incoming dNTP (dCTP, dATP, dGTP) is oxoG. Our results suggest that pol X accommodates the oxoG_syn:A mispair by sampling closed active conformations that mirror those observed in traditional Watson-Crick complexes. Moreover, for both the oxoG_syn:A and oxoG:C ternary complexes, conformational sampling of the polymerase follows previously described large subdomain movements, local residue motions, and active site reorganization. Interestingly, the oxoG_syn:A system exhibits superior active site geometry in comparison to the oxoG:C system. Simulations for the other mismatch basepair complexes reveal large protein subdomain movement for all systems, except for oxoG:G, which samples conformations close to the open state. In addition, active site geometry and basepairing of the template base with the incoming nucleotide, reveal distortions and misalignments that range from moderate (i.e., oxoG:A_syn) to extreme (i.e., oxoG_anti/syn:G). These results agree with the available kinetic data for pol X and provide structural insights regarding the mechanism by which this polymerase can accommodate incoming nucleotides opposite oxoG. Our simulations also support the notion that α-helix E is involved both in DNA binding and active site stabilization. Our proposed mechanism by which pol X can preferentially accommodate dATP opposite template oxoG further underscores the role that enzyme dynamics and conformational sampling operate in polymerase fidelity and function.     

The encounter of distinct Morimus asper (Coleoptera: Cerambycidae) phylogeographic lineages on the Balkan Peninsula: conservation implications

Journal of Insect Conservation - The first step in monitoring and management of any taxa includes resolving taxonomic ambiguities which complicate the identification of its management units. One of...     

Anticooperative Binding Governs the Mechanics of Ethidium-Complexed DNA

DNA intercalators bind nucleic acids by stacking between adjacent basepairs. This causes a considerable elongation of the DNA backbone as well as untwisting of the double helix. In the past few years, single-molecule mechanical experiments have become a common tool to characterize these deformations and to quantify important parameters of the intercalation process. Parameter extraction typically relies on the neighbor-exclusion model, in which a bound intercalator prevents intercalation into adjacent sites. Here, we challenge the neighbor-exclusion model by carefully quantifying and modeling the force-extension and twisting behavior of single ethidium-complexed DNA molecules. We show that only an anticooperative ethidium binding that allows for a disfavored but nonetheless possible intercalation into nearest-neighbor sites can consistently describe the mechanical behavior of intercalator-bound DNA. At high ethidium concentrations and elevated mechanical stress, this causes an almost complete occupation of nearest-neighbor sites and almost a doubling of the DNA contour length. We furthermore show that intercalation into nearest-neighbor sites needs to be considered when estimating intercalator parameters from zero-stress elongation and twisting data. We think that the proposed anticooperative binding mechanism may also be applicable to other intercalating molecules.     

Neuronal and muscular alterations caused by two wheat endosperm proteins,puroindoline-a and alpha1-purothionin,are due to ion pore formation

Using the patch-clamp technique it was found that the toxicity of the two wheat endosperm proteins puroindoline-a and alpha1-purothionin probably results from the dissipation of ion concentration gradients essential for the maintenance of cellular homeostasis.Abbreviations PIN-a puroindoline-a - PTH alpha1-purothionin Presented at the Biophysical Society Meeting on Ion Channels—from structure to disease held in May 2003, Rennes, France     

Echocardiographic measurement of cardiac output in rats

The systematic evaluation of different transthoracic echocardiographic (TTE) methods to determine cardiac output (CO) and the effect of changes in intravascular volume on echocardiographically determined indexes of cardiovascular structure in the rat has not been documented. With the use of 11 Wistar rats, simultaneous echocardiographic and thermodilution measurements of CO were compared at baseline and after blood withdrawal or transfusion at 43 different levels of intravascular volume and using 10 different echocardiographic approaches. The best correlation (r = 0.93; P < 0.0001), least bias (-3 ml/min), and best precision (16 ml/min) between thermodilution and echocardiographic methods were obtained at the level of aortic annulus using pulsed Doppler. In conclusion, CO could be accurately assessed in rats using TTE and pulsed Doppler at the level of the aortic annulus. This annulus was demonstrated to remain stable, but pulmonary annulus, thoracic aorta, mitral valve, and left ventricular diameters were found to be more modifiable during volumic changes.     

The control of the proventriculus in the honeybee (Apis mellifera carnica L.) II. Feedback mechanisms

The mechanisms underlying the control of solution transport rates through the proventriculus in foraging honeybees were investigated in individuals trained to collect defined amounts of sugar solutions. Following feeding, bees were injected either with metabolisable (glucose, fructose, trehalose), or non-metabolisable (sorbose) sugars, in order to distinguish between haemolymph osmolarity and haemolymph sugar levels as factors controlling the solution transport rates through the proventriculus. After a fixed period, workers were dissected in order to measure crop content and haemolymph sugar titers. Between feeding and dissection, the metabolic rate of every investigated forager was measured using open-flow respirometry. Bees injected with metabolisable sugars 15 min after feeding were observed to reduce their solution transport rates through the proventriculus, but injection of non-metabolisable sugars had no influence on them. This suggests that the solution transport rate through the proventriculus is controlled by the concentration of metabolisable compounds in the haemolymph, and not by the haemolymph osmolarity. A period of 10 min after injection of metabolisable sugars was enough to observe reduced solution transport rates. However, if bees were injected only 5 min after feeding, no reduced solution transport rates were observed 10 min after injection.