自溶法回收鱼类加工废弃物中蛋白质成分

鱼头和鱼内脏为鱼类在加工过程中废弃的主要组织,其中含有丰富的蛋白质和脂肪等有益成分,有必要进行回收利用。双鳍舵鲣鱼的头部和内脏约占其鱼体重量的30％,富含蛋白质(14.4％-22.6％)。为了将这些废弃物中的蛋白质进行回收,分别采用双鳍舵鲣鱼内脏本身含有的内源性蛋白酶(自溶)和四种外源性的商业蛋白酶Papain W-40(E1),Pancidase NP-2(E2),Sumichiimu FP(E3)和Protease M(E4)对废弃物中的蛋白质进行水解(50℃,1～4h),考察自溶和不同酶解方法对蛋白质的回收率以及对回收液氨基酸组成的影响。结果显示,自溶法对废弃物中蛋白质的回收效果最好。当水解温度为50℃,水解时间为2h时,自溶法的蛋白质回收率最高,达到76％;其次为E2酶解法,回收率达到70％;E3酶解法效果最差,回收率为63％。进一步研究表明,自溶回收液(AE)的氨基酸总量也最高,达到11756 mg/100g,而采用E1、E2、E3和E4水解方法得到的酶解回收液(EE1、EE2、EE3和EE4)中氨基酸含量分别仅为10294、10642、8750、10121 mg/100g。感观评定结果表明,自溶回...     

Congenital malformations of the external and middle ear accompanied by temporal bone anomaly in a calf

A 7-month-old female Holstein calf presented with bilateral microtia and absent external acoustic meatus. The real-time polymerase chain reaction test was negative for bovine viral diarrhea virus and bovine leukemia virus. The calf’s dam had a normal reproductive history. Computed tomography confirmed bilateral atresia of external auditory canals, aplasia of tympanic cavities and the ossicular chain, and temporomandibular joint abnormality. Necropsy revealed a severe malformation of the temporal bone. In the tympanic region, the external acoustic pore, tympanic bulla, and muscular process were absent bilaterally. The bilateral inner ear structure was normal. Based on these findings, we diagnosed the present case as congenital malformations of the external and middle ear accompanied by temporal bone anomaly.     

Accuracy and precision of crown profile,volume, and surface area measurements of 29-year-old Japanese cypress trees using a Spiegel relascope

The crown profile, volume, and surface area obtained from 25 trees in a stand of 29-year-old Japanese cypress (Chamaecyparis obtusa Endl.) using a Spiegel relascope were compared with those obtained by direct measurement after tree felling. In 17 of the 25 trees, the crown profile measured with the relascope was identical to the crown profile obtained by direct measurement. For the 17 trees, the mean relative errors of crown volume and surface area tended to be unbiased. On the other hand, the crown profiles obtained by the two methods were different in five of the 25 trees, while it could not been judged whether the crown profiles obtained by the two methods were identical or different in three of the 25 trees. However, for each group of five or three trees, the mean relative errors of crown volume and surface area were also unbiased. Moreover, for both crown volume and surface area, no significant differences were detected in variance of error among the groups of 17, five, and three trees. Therefore, the discrepancy between crown profiles obtained by the two methods for the five and three trees might be negligible in terms of the accuracy and precision of crown volume and surface area measurements. The standard errors for both crown volume and surface area were larger in each of the five and three trees than in the 17 trees. However, even for the five and three trees, the crown volume and surface area obtained using the relascope were more precise than those based on the assumption that crown form was a cone or paraboloid. We concluded that using a Spiegel relascope would enable us to obtain an accurate and precise crown profile, volume, and surface area of Japanese cypress trees for practical use, especially when the main objective of measurement is determining crown volume or surface area.     

Nutritional characteristics of sago palm and oil palm in tropical peat soil

To make clear the nutritional characteristics of sago palm (Metroxylon sagu Rottb.) and oil palm (Elaeis guineensin Jacq.) grown in tropical peat soil, minerals concentration, organic compounds concentration, and photo‐synthetic rate were estimated, and the obtained results were as follows. Since, the nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sodium (Na) concentration in mature leaves and trunk were higher in the oil palm than in the sago palm, but potassium (K) concentration was higher in the sago palm than in the oil palm, the minerals (especially N, P, Ca, and Mg) requirement for the oil palm were higher than in the sago palm. This indicates that the sago palm will adapt better than the oil palm to soils with poor nutrients. The manganese (Mn) and zinc (Zn) concentration in leaves of the sago palm and Ca and aluminum (Al) concentration in leaves of the oil palm increased with the increase of aging, indicating that those elements are eliminated from plants through leaf senescence. In the sago palm, the N and P distribution ratio to leaves remained almost constant during growth, indicating that N and P were predominantly distributed to leaves for maintaining leaf function. The photosynthetic rate [μmole carbon dioxide (CO₂) m² LA sec^‐1] at light saturation was lower in the sago palm (5.8) and oil palm (10.0) than in wheat (25.4). As leaf longevity of sago and oil palms was longer (about 12 times) than that of wheat (Triticum aevstium L.), and the minerals concentration and photosynthetic rate remained constant for a long duration of growth, the cumulative carbon (C) accumulation per unit dry weight (photosynthetic rate x leaf longevity) in the individual leaf is assumed to be equal or greater than that of wheat. The photosynthetic ability of sago and oil palms leaves is very important for understanding why sago and oil palms have high productivity in spite of a low nutrient environment.     

Comparison of factors affecting recruitment variability of walleye pollock Theragra chalcogramma in the Pacific Ocean and the Sea of Japan off northern Japan

The Japanese Pacific stock (JPS) and the northern Japan Sea stock (JSS) of walleye pollock Theragra chalcogramma are mainly distributed in the Pacific Ocean and the Sea of Japan off northern Japan, respectively. This paper summarizes and compares the factors affecting the recruitment variability of these two stocks. Spawning season is from December to March for both stocks. JPS recruitment has a positive relationship with the water temperature in January and February, whereas that of JSS has a negative relationship with the water temperature in January, February, and April. One possible reason for this is that pollock larvae have an optimum growth temperature of approximately 5 °C in the field. Drift of early life stages also appears to be an important influence on the recruitment of both stocks. Because the current generated by the northwest wind carries eggs of JPS into the main larval nursery ground, JPS recruitment is enhanced in years when the northwest wind is predominant in February. On the other hand, early life stages of JSS are transported into the nursery ground by the Tsushima Warm Current. However, this current also carries early life stages into the Sea of Okhotsk and offshore, resulting in poor JSS recruitment in years when this current is strong in March. In contrast to JPS, the recruitment of which is significantly impacted by cannibalism, young pollock have not been found in the stomachs of adult JSS. Warm temperatures in the Sea of Japan seem to induce the separation of young and adult pollock, and the shape of the stock–recruitment relationship also suggests that cannibalism is not important for JSS. Based on this knowledge, and on the hatch date distributions of larvae and juveniles, we propose mechanisms that can explain the recruitment fluctuations for JPS and JSS pollock.     

Long-term rearing of Japanese eel larvae using a liquid-type diet: food intake,survival and growth

Fisheries Science - The efficiency of a new liquid-type diet for long-term rearing of Japanese eel larvae until metamorphosis was examined, as was the effect of diet viscosity on diet intake and on...     

Persistence of uterine bacterial infection,and its associations with endometritis and ovarian function in postpartum dairy cows

We investigated the relationship between the persistence of uterine bacterial infections with cytologically determined endometritis and ovarian function in 65 postpartum Holstein cows. Vaginal mucus discharges were collected, and endometrial smear samples (n = 130) were collected for cytological and bacteriological examinations from the cows at weeks 5 and 7 postpartum (pp). Blood samples were collected at weeks 3, 5 and 7 pp to determine plasma progesterone concentrations to monitor ovarian activity. According to the bacteriological examination, cows were classified into four groups. The first group (n = 32; 49%) comprised cows negative for bacteria at weeks 5 and 7 pp. The second group (n = 11; 17%) comprised cows with bacterial infections at week 5 pp but that were clear of infection at week 7 pp. The third group (n = 12; 19%) comprised cows without bacteria at week 5 pp but that acquired an infection by week 7 pp. The fourth group (n = 10; 15%) comprised cows with bacterial infections at weeks 5 and 7 pp (persistence of infection). A positive correlation (P < 0.001) was noted between the severity of cytologically determined endometritis, purulent vaginal discharge and the persistence of infection. Cows with persistent infections had a significantly (P < 0.01) prolonged luteal phase compared with cows without infection. In conclusion, the prevalence of cytologically determined endometritis and prolonged luteal phase were significantly increased in cows with persistent infections.     

Steep slopes promote downhill dispersal of Quercus crispula seeds and weaken the fine-scale genetic structure of seedling populations

The seed dispersal patterns and genetic structure of plant populations in mountainous forests may differ from those on flat sites, because some seeds that fall from adults are likely to roll downhill, and thus cause the seed shadows from different mother trees to merge. In the study reported here we used six polymorphic microsatellite markers to track seed dispersal and examine the fine-scale spatial genetic structure of adults and first-year seedlings of Quercus crispula in 2500 m² plots on four slopes. In each of the four plots, leaves of adults, seedlings and endocarps of hypogeal cotyledons attached to the seedlings were genotyped to identify the seedlings’ mother trees. The results showed that steeper slopes result in larger dispersions and smaller genetic structure of seedlings. These findings are a crucial step towards an understanding of the effect of topography on tree regeneration.     

Isolation and characterization of a novel anionic peroxidase cDNA found in poplar (Populus nigra) suspension cultured cells

A cDNA clone fromPopulus nigra L. var.italica Koehne, denoted PCY2-6, coding for an anionic peroxidase has been isolated, cloned, and characterized. PCY2-6 is 1160 bp long; and its deduced product, PnC26, contains 343 amino acid residues. The mature protein has a calculated isoelectric point of 4.09. The protein contains two motifs typical of peroxidase and 10 potentialN-glycosylation sites. PnC26 is therefore classified as an anionic peroxidase. The mRNA of the PCY2-6 gene family was detected in immature and mature leaves and in two parts of current-year stems: the shoot tip and the older stem. The mRNA of PCY2-6 gene family was found to localize in the phloem and cortex of the current-year stems. We therefore conclude that expression of the PCY2-6 gene family is related to bark development.