Effects of arm and leg loading on sprint performance

The effects of loading on sprint kinematics were examined in 24 male students. The moment of inertia of either the arms or legs was increased by up to 50% of their unloaded values and the time for distances of 0.5–15 m and 15–30 m from a sprint start was measured. An increase in leg loading was associated with a gradual decrease in velocity of both sprint phases, while the change associated with arm loading was modest and significant only in the second phase. The decrease in sprint velocity was predominantly due to a reduction in stride rate, while the stride length remained almost unchanged. It was concluded that leg loading affected sprint velocity more than arm loading, and also that the velocity was reduced due to a decrease in the stride rate rather than in the stride length. Accepted: 10 November 1997     

Peculiarities of the amino acid composition, spatial organization and interaction with DNA of histones H1 from calf thymus and carp spermatozoa

The amino acid composition of the H1-like histone isolated from carp spermatozoa (H1carp) is characterized by a high content of lysine (34.6%) and a low content of glycine (4.5%) as compared to that of its calf counterpart (H1calf). The Lys/Arg ratio is 21.6, which is much higher than that for the H1-like histones from other species spermatozoa (cf. echinodermata). It was shown that the fluorescence anisotropy and excitation spectra of histones H1carp and H1calf change synchronically. At the same time the final folding of the polypeptide chains of these histones within their ternary structure is different. These differences manifest themselves in a distinct quantum yield of both histones and different accessibility of the single tyrosine residue for fluorescence quenchers. In histone--DNA complexes the tyrosine fluorescence is quenched. An increase in the ionic strength gives rise to a formation of large-sized aggregates in a histone H1--DNA solution which contain structurally heterogenous histones H1 from different sources. Histone H1carp causes DNA aggregation at lower ionic strength values than its calf counterpart. The complexes are dissociated at 0.6 M NaCl.     

Prevalence of rare F5 variants in general population from Bosnia and Herzegovina

Molecular Biology Reports - Human gene F5, encoding coagulation factor V, was previously reported to be highly polymorphic. Apart from FV Leiden, several other rare variants have been detected in...     

The content of lead in herbal drugs and tea samples

Heavy metals are highly toxic to living organisms even in low concentrations owing to their cumulative effect. In this study the overall content of lead in herbal drugs was determined, as well as the content of lead which was released from tested drugs during the preparation of tea drinks. To determine the content of toxic lead, the highly sensitive microanalytical technique of the potentiometric stripping analysis (PSA) with oxygen as the oxidant was used. The lowest overall content of lead was detected for chamomile and ranged from 0.73 to 0.77 ??g/g, while the greatest content of lead was determined in the samples of the frangula bark, and yielded approximately 3 ??g/g. The lead content in the prepared tea drinks ranged from 0.26 to 1.23 ??g/g and depended on the manner in which tea drink was prepared. All of the herbal drugs in this study contain a certain amount of the toxic metal lead, but at the same time, the contents were below the levels prescribed for this metal. The content of lead released from the herbal drug into the tea drink was three to five times lower than those of the overall content of this metal.     

Redox-Coupled Protonation of Respiratory Complex I: The Hydrophilic Domain

Respiratory complex I, NADH:ubiquinone oxidoreductase, is a large and complex integral membrane enzyme found in respiring bacteria and mitochondria. It is responsible in part for generating the proton gradient necessary for ATP production. Complex I serves as both a proton pump and an entry point for electrons into the respiratory chain. Although complex I is one of the most important of the respiratory complexes, it is also one of the least understood, with detailed structural information only recently available. In this study, full-finite-difference Poisson-Boltzmann calculations of the protonation state of respiratory complex I in various redox states are presented. Since complex I couples the oxidation and reduction of the NADH/ubiquinone redox couple to proton translocation, the interaction of the protonation and redox states of the enzyme are of the utmost significance. Various aspects of complex I function are presented, including the redox-Bohr effect, intercofactor interactions, and the effects of both the protein dielectric and inclusion of the membrane.