Hypoxanthine enhances the cured meat taste

We evaluated the enhancement of cured meat taste during maturation by sensory analysis. We focused on the heat‐stable sarcoplasmic fraction (HSSF) to identify the factors related to cured meat taste. Because the dry matter of HSSF contained more than 30% nitrogen, nitrogen compounds such as free amino acids, small peptides and adenosine triphosphate‐related compounds seemed to be the important components of HSSF. The samples cured with HSSF for 2 h exhibited the same taste profile as ones cured without HSSF for 168 h. Therefore, the changes in the amount and fractions of nitrogen compounds were examined in HSSF during incubation from 0 to 168 h. The concentration of hypoxanthine (Hx) gradually increased, while inosine‐5′‐monophosphate decreased during the incubation. The samples cured with pickles containing various concentrations of Hx were subjected to sensory analysis. The addition of Hx, in a dose‐dependent fashion, enhanced cured meat taste by maturation for 2 h. It was concluded that Hx is essential for the enhancement of cured meat taste.     

Comparative analysis of mechanical stretch-induced activation activity of back and leg muscle satellite cells in vitro

It has previously been shown that mechanical stretch induces activation of cultured quiescent satellite cells by rapid release of hepatocyte growth factor (HGF) from its extracellular association with satellite cells and its subsequent presentation to the c‐met receptor. The present study provides evidence that the stretch activation activity varies according to the origin of satellite cells from back and leg skeletal muscles in vitro. Satellite cells were isolated from three muscle groups, back (BK), upper hind limb (UL) and lower hind limb (LL) muscles, of adult male rats and stretch activation activities were compared. In response to stretch, lower hind limb satellite cells showed significantly greater response than upper hind limb and back muscles (LL > UL > BK). Immunoblots of stretched culture media revealed a higher HGF‐releasing capacity of lower hind limb satellite cells than back muscle satellite cells. In addition, lower hind limb satellite cells exhibited a greater activation activity in response to exogenous HGF added to culture media than compared to satellite cells from back and upper hind limb (LL > UL > BK). The increased ability to release HGF and the increased cellular responsiveness might account for higher stretch activation activities of lower hind limb satellite cells. Electrophoretic analysis of myosin heavy chain isoforms verified a higher content of slow muscle fibers in lower limb muscles (LL > UL > BK), suggesting a difference in stretch‐induced activation activity between satellite cells associated with fast and slow muscle fibers.     

I-72杨林的竞争密度效应

用竞争密度(C—D)效应的倒数式(即t/w=Api B，式中w和pi分别为平均单株材积和密度，A和B为系数)分析了I-72杨林的生长过程。在双对数图上，I-72杨林各生长阶段的平均单株材积和密度的观察值很好地吻合了竞争密度效应曲线，竞争密度效应曲线随时间的推移向上移动。通过分析得出了生物时间τ(逻辑斯蒂生长曲线中生长系数λ(t)的积分)，系数A和B，生长系数λ(t)和最终收获量Y(t)的变化趋势及系数A和B的生物学意义。生物时间τ随着物理时间t的增加而增加。随着τ的增加，系数A急剧增加到最大值后逐渐下降，而系数B呈指数下降，倾向于接近零。随着林分的生长，生长系数λ(t)倾向于下降，而最终收获量Y(t)逐渐增加。以C-D效应为基础，提出了对高密度的7a生I-72杨林进行间伐的建议。     

Maintenance and growth respiration of the aboveground parts of young field-grown hinoki cypress (Chamaecyparis obtusa)

Aboveground respiration of five 8-year-old trees of field-grown hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) was nondestructively measured at monthly intervals over 1 year with an enclosed standing tree method. The relationship between monthly specific respiration rate and monthly mean relative growth rate at the individual tree level was described by a linear equation. During the dormant season, respiration was used mainly for maintenance purposes, whereas during the growing season, more than 40% of the respiration was used for growth purposes, i.e., 60 to 70% in May. We conclude that annual maintenance and growth respiration of a tree are directly proportional to the aboveground phytomass and its annual increment, respectively. The maintenance coefficient was estimated to be 0.504 +/- 0.039 (SE) kg kg(-1) year(-1), indicating that the amount respired for maintaining already existing phytomass was equivalent to about half of the existing phytomass. The growth coefficient was estimated to be 0.772 +/- 0.043 (SE) kg kg(-1), indicating that the amount respired for constructing new phytomass was equivalent to about three-fourths of the annual phytomass increment. The annual stand maintenance and growth respiration were, respectively, 8.8 Mg ha(-1) year(-1) for an aboveground biomass of 17.4 Mg ha(-1) and 5.0 Mg ha(-1) year(-1) for an annual stand aboveground biomass increment of 6.5 Mg ha(-1) year(-1). About two-thirds of the total respiration was used to maintain already existing biomass, and about one-third was used to construct new biomass.     

Root respiration in Chamaecyparis obtusa trees

We examined the respiration rate of root segments, which had a constant length in relation to their diameter, from three small and two large 26-year-old Chamaecyparis obtusa (Siebold & Zucc.) Endl. trees. The dependence of respiration rate on segment diameter was described by a power function with an exponent of about 1.5, except for the smallest sample tree, for which the exponent was 1.74. Unlike stem segments, root segments of similar diameter showed similar rates of respiration regardless of the tree from which the root segments had been taken. On the basis of the power function, we propose a new equation to estimate the total root respiration rate of a tree. The relationship between root respiration rate per tree and root weight can be expressed by a power function with an exponent of 1.11. The ratio of the specific respiration rate of stems to that of roots was 0.7 for the three smaller trees, and 1.1 to 1.3 for the two larger trees. In November, the stand respiration rate of roots was estimated to be 0.36 kg CO(2) ha(-1) h(-1) for a root biomass (dry weight) of 28 Mg ha(-1).     

The importance of subfragment 2 and C‐terminus of myosin heavy chain for thick filament assembly in skeletal muscle cells

In skeletal muscle cells, myofibrillar proteins are highly organized into sarcomeres in which thick filaments interdigitate with thin filaments to generate contractile force. The size of thick filaments, which consist mainly of myosin molecules, is strictly controlled. However, little is known about the mechanisms by which myosin molecules assemble into thick filaments. Here, we assessed the ability of each domain of myosin heavy chain (Myh) to form thick filaments. We showed that exogenously expressed subfragment 2 (S2) + light meromyosin (LMM) of Myh was efficiently incorporated into thick filaments in muscle cells, although neither solely expressed S2 nor LMM targeted to thick filaments properly. In nonmuscle COS7 cells, S2+LMM formed more enlarged filaments/speckles than LMM. These results suggest that Myh filament formation is induced by S2 accompanying LMM. We further examined the effects of Myh C‐terminus on thick filament assembly. C‐terminal deletion mutants were incorporated not into entire thick filaments but rather into restricted regions of thick filaments. Our findings suggest that the elongation of myosin filaments to form thick filaments is regulated by S2 as well as C‐terminus of LMM.     

Genetic identification and morphology of naturally spawned eggs of the Japanese eel Anguilla japonica collected in the western North Pacific

Eggs of the Japanese eel Anguilla japonica collected in the western North Pacific were identified by onboard species-specific polymerase chain reaction (PCR) and DNA nucleotide sequencing after the cruise. Fish eggs of various species were collected by large plankton net tows at 12 stations along the southern part of the West Mariana Ridge on 19–25 May 2009. A total of 43 fish eggs were distinguished morphologically as possibly being of A. japonica. Thirty-one of those were analyzed by PCR, which included 15 eggs collected at 12°50–55′N, 141°15–20′E (in 5 tows) that showed positive results. The 16S ribosomal RNA (rRNA) gene sequences of eggs determined after the cruise indicated that 31 A. japonica eggs had been collected. The remaining eggs were of mesopelagic eel species (Serrivomeridae and Derichthyidae), or unidentified species. The morphological characteristics of the A. japonica eggs were consistent with those of artificially spawned eggs, except they had a slightly larger diameter. The egg diameter range did not overlap with those of mesopelagic eels of the Serrivomeridae, which often spawn in the same area as A. japonica. These results suggest that egg diameter and embryo shape can be used to morphologically identify naturally spawned A. japonica eggs.     

不同播种期对津川1号产量及品质食味影响的研究

通过对津川1号的不同播种期试验,比较分析了处理间产量、产量构成要素及品质食味的差异性,以期为优质水稻品种津川1号选择合理的播种时期提供理论指导。结果表明:津川1号的适宜播种期为4月中下旬,过晚,不仅产量会显著降低,而且会增加直链淀粉含量、降低粘性,进而降低其食味品质。     

Green and black tea suppress hyperglycemia and insulin resistance by retaining the expression of glucose transporter 4 in muscle of high-fat diet-fed C57BL/6J mice

To investigate the preventive effects of tea on hyperglycemia and insulin resistance, male C57BL/6J mice were given a high-fat diet containing 29% lard and also green or black tea ad libitum for 14 weeks. Both teas suppressed body weight gain and deposition of white adipose tissue caused by the diet. In addition, they improved hyperglycemia and glucose intolerance by stimulating glucose uptake activity accompanied by the translocation of glucose transporter (GLUT) 4 to the plasma membrane in muscle. Long-term consumption of the high-fat diet reduced levels of insulin receptor β-subunit, GLUT4 and AMP-activated protein kinase α in muscle, and green and black tea suppressed these decreases. The results strongly suggest that green and black tea suppress high-fat diet-evoked hyperglycemia and insulin resistance by retaining the level of GLUT4 and increasing the level of GLUT4 on the plasma membrane in muscle.     

Effect of liquid whey feeding on fecal microbiota of mature and growing pigs

The effect of liquid whey feeding on fecal bacteria and their metabolites was assessed in five pregnant sows and 66 growing pigs. Sows were fed a control diet for 4 weeks (control period) followed by the same diet but with whey feeding (5 L/day/pig) for 4 weeks (whey period). One group of growing pigs was given 267 L of whey per pig (whey group), while the other group was not (control group). In both cases, liquid whey was given separately from control diet. Sows in the whey period had feces showing lower pH, lower ammonia concentration, and larger population sizes of total bacteria, lactobacilli and bifidobacteria. The bacterial gene library analysis indicated that Mitsuokella and Megasphaera were more frequently detected, while Clostridium disporicum were detected less frequently in the whey period. Feces from whey‐fed growing pigs showed lower pH than that from control pigs in the early stage of growing. Also, larger populations of total bacteria, lactobacilli and bifidobacteria were recorded in the whey group. From the bacterial gene library analysis, the detection frequency of Lactobacillus reuteri tended to be higher in the whey group. These results indicate that whey feeding influences the hindgut microbiota of pigs, possibly leading to a fermentation shift that is favorable for animal health.