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The α-helix of myosin decreased and the diameter of the myosin clusters increased monotonically with increasing heating time at 50 and 90°C. The clusters that formed during heating at 90°C were much larger than those that formed at 50°C. With increasing heating time, the G′ of the myosin heated at 50°C increased, but it decreased in the myosin heated at 90°C. The rheology data suggested that myosin heated at 50°C exhibited better gel formation than myosin that was heated at 90°C. The myosin gel network formed at 50°C was more consistent and homogeneous, whereas the gel formed 90°C was irregular and sturdy. Myosin heated at 50°C tended to form small, open clusters via heads, and the tails were outstretched, whereas the clusters that formed via myosin heads and tails at 90°C were larger and closed.

Amino acids containing L-Arginine (Arg), L-Lysine (Lys) and L-Histidine (His) are recognized to increase the solubility of myosin at low ionic strength, but there is a difference in the researchers' views on their effects on the secondary structure of myosin. To elucidate which method is relatively appropriate for the determination of secondary structures of myosin added with Arg, Lys or His, Circular dichroism (CD) spectra and Raman spectroscopy were carried out respectively. Raman spectroscopy was more suitable than CD method for determination of the secondary structures of myosin added with His, while CD spectra was more accurate for the myosin samples added with Lys and the adequate concentration of Lys should be under 10 mM. Both CD and Raman methods could be applied to myosin added with Arg, however, the latter was recommended and the adequate additive content of Arg in CD method should be less than 10 mM.

The effect of a salt substitute (SS) containing L-lysine (Lys) and L-histidine (His) on secondary structure and gel properties of myosin from grass carp was examined. The results indicated that the α-helix content of myosin treated with SS was 29.00%, 29.03% and 35.93% more than that with NaCl at 0.4, 0.6 and 0.8 mol/L (P < 0.05), respectively, suggesting that some fractions of the β-sheet, β-turn and random coil were transformed into α-helix. A similar pattern of storage modulus (G') was found between NaCl and SS treatments, and the G' of SS treatments at the end of gelation completion was higher than that of NaCl treatments. The salt substitute improved the gel strength and hardness of myosin at 0.4, 0.6 and 0.8 mol/L. The results indicated that the changes in secondary structure and gel properties of myosin may be mainly due to the L-lys and/or L-his in salt substitute.

The study examined the effect of refrigerated storage on antioxidant activities, lipid and protein oxidation, fatty acids (FAs), drip loss and color of semimembranosus (SM) muscle from goats. Samples of SM were obtained from carcasses of 15 Boer bucks (7 months old; body weight, 32.18 ± 0.81 kg) subjected to an 8 d storage at 4°C. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activities were stable while carotenoid, tocopherol, water holding capacity and redness declined (P < 0.05) as storage progressed. Carbonyl content increased from 1.85 to 4.73 nmol/mg protein while thiol content reduced from 54.22 to 42.82 nmol/mg protein. The TBARS value increased from 0.2 to 0.8 mg MDA/kg. SDS-PAGE expression of myosin heavy chain (MHC) decreased (P < 0.05) from 72.45 to 49.82 density/mm 2 while actin reduced (P > 0.05) from 14.00 to 13.08 density/mm 2 . The concentrations of n-3 and n-6 FA decreased while the saturated FA increased over storage. Correlations (P < 0.05) were found between antioxidant vitamins and quality indicators of chevon.

Fifty years ago, an important paper appeared in Botanical Magazine Tokyo. Kamiya and Kuroda proposed a sliding theory for the mechanism of cytoplasmic streaming. This pioneering study laid the basis for elucidation of the molecular mechanism of cytoplasmic streaming--the motive force is generated by the sliding of myosin XI associated with organelles along actin filaments, using the hydrolysis energy of ATP. The role of the actin-myosin system in various plant cell functions is becoming evident. The present article reviews progress in studies on cytoplasmic streaming over the past 50 years.

Abstract Introduction: Genetics has been suggested as an explanation for the etiology of malocclusions, although some questions, due to the perception that genetic inheritance is tied to a monogenic or Mendelian form of inheritance. Objective: This paper describes the inheritance of malocclusions, highlighting the areas of knowledge where research has explored mechanisms that explain deviations in patterns of craniofacial growth. Conclusion: Malocclusions have a complex or multifactorial pattern of inheritance, where more than one gene is involved in the development of the phenotype. There is also the possibility that the environment influences malocclusions. Resumo Introdução: a genética tem sido proposta como uma explicação para a ocorrência das más oclusões, mas isso é questionável, pois a percepção do significado de herança genética está vinculada à herança mendeliana ou monogênica. Objetivo: o presente artigo visa discorrer sobre a herança das más oclusões e ressaltar as áreas do conhecimento nas quais a pesquisa tem explorado mecanismos que explicam a ocorrência de desvios do padrão de crescimento facial. Conclusão: as más oclusões têm um padrão de herança complexo ou multifatorial, no qual mais de um gene está envolvido no desenvolvimento do fenótipo. Isso quer dizer que existe, também, uma potencial influência do ambiente nas más oclusões.

In the present work the myosin molecule from jumbo squid mantle (Dosidicus gigas) was isolated and characterized with the aim to evaluate the influence of ionic strength on its gelling properties. It was found that the myosin molecule possesses different chemical and structural characteristics than other vertebrates and invertebrates species, such as some cephalopods, which might explain differences in gelation in comparison to those from other organisms. A lower content of total sulfhydryl groups (TSH) possibly caused an improvement in the myosin molecule flexibility when the ionic strength increased (p ˂ 0.05). The aforementioned possibly affected (p ˂ 0.05) the enzyme activity, surface hydrophobicity, viscosity and RSH groups. The results demonstrate that the myosin molecule from jumbo squid is structurally different from the rest of the marine species.

The enzymatic dissociation of short muscles from mice, such as flexor digitorum brevis, has allowed a great accumulation of physiological, pharmacological and biochemical knowledge about skeletal muscle. However, this body of knowledge has been restricted to the types of fibers present in these muscles. Information about the other fiber types has been limited and has been primarily obtained by the manual isolation of fibers from other species, typically rats, via a difficult and time-consuming procedure. In this report, the author describes a technique for the enzymatic dissociation of long muscles, such as soleus or extensor digitorum longus (EDL), which can be applied to study a wider spectrum of fiber types and larger quantities of cells. Additionally, the kinetics of Ca2+ transients obtained in soleus and EDL fibers are compared in this report. The usefulness of this methodology for other physiological, biochemical and molecular biology experiments is also discussed. This methodology introduces the possibility of using the whole spectrum of fiber types to study normal muscle biology and the pathophysiology of muscle diseases.

:  Enzymatic and structural properties of white croaker fast skeletal muscle myosin were determined and compared with those of walleye pollack counterpart. Ca2+‐ATPase activity of white croaker myosin was decreased to approximately 70% of the original activity during 1 day of storage at 0°C and pH 7.0 in 0.5 M KCl and 0.1 mM dithiothreitol, whereas that of walleye pollack was decreased to approximately 20% under the same condition. The activation energy (Ea) for inactivation of white croaker myosin calculated by the Arrhenius plot for inactivation rate constant (KD) was 1.2‐fold higher than that of walleye pollack. While Ca2+‐ATPase showed a similar KCl‐dependency for the two species, the maximal activity was observed at pH 6.2 and 6.3 for white croaker and walleye pollack, respectively. Actin‐activated myosin Mg2+‐ATPase activity of white croaker was approximately half that of walleye pollack at 0.05 M KCl and pH 7.0, although the two myosins showed a similar affinity to F‐actin with Km of 1.7 and 1.4, respectively. Limited proteolysis with α‐chymotrypsin cleaved heat‐denatured white croaker myosin mainly at heavy meromyosin/light meromyosin (HMM/LMM) junction, whereas walleye pollack myosin was cleaved at several sites in LMM as well as at the HMM/LMM junction.

The effects of specific marinades on the thermal stability of the muscle proteins using differential scanning calorimetry (DSC) was examined. Various marinades were tested, composed mainly of NaCl as well as triphosphates and organic acids, self made marinades, and ready-to-use marinades used in industrial practice. As a result of the experiment conducted, it was found that all marinades used changed significantly the thermal stability of muscle proteins. The use of sodium chloride and sodium triphosphate for marination caused a reduction of enthalpy and denaturation temperature of myosin and actin. However, a greater influence on the stability of muscle proteins was observed with marinades containing organic acids (acetic and citric). The most significant reduction of the denaturation temperatures and enthalpy (to the lowest level of 0.56 J/g) was found for self made marinade composed of 20.7% cider vinegar and 16% lemon juice.