Effects of protein phosphatase inhibitor calyculin a on the postacrosomal protein serine/threonine phosphorylation state and acrosome reaction in boar spermatozoa incubated with a cAMP analog

In order to reveal the involvement of the sperm postacrosomal region in the acrosome reaction, we examined the effects of the protein phosphatase inhibitor calyculin A on the postacrosomal protein serine/threonine phosphorylation state and acrosome morphology in boar spermatozoa incubated with a cAMP analog. Proteins were highly phosphorylated on the serine/threonine residues only in the postacrosomal region before incubation. After 90-min incubation without calyculin A, the protein phosphorylation state declined in the postacrosomal region irrespective of the capacitation state while it remained under the detectable level in the other regions of the sperm head. However, addition of calyculin A effectively suppressed the decline in protein phosphorylation state and increased an inactive form of protein phosphatase 1 in the postacrosomal region. On the other hand, this inhibitor had no influence on the protein phosphorylation state in the acrosome and equatorial segment. After incubation without calyculin A for 180 or 360 min, many spermatozoa exhibited acrosomal changes and loss that indicated occurrence of the acrosome reaction. However, addition of calyculin A significantly blocked these events. These results are consistent with our suggestion that postacrosomal serine/threonine-phosphorylated proteins are involved in suppression of the acrosome reaction in boar spermatozoa in vitro.     

氧化鱼油与棕榈油对花鲈肝脏抗氧化酶及组织结构的影响

在21个200 L圆形流水水槽中各放养花鲈(Lateolabrax maculatus)幼鱼,初始体质量为(1.73±0.01)g.在相同的环境条件下投喂以棕榈油(P)与新鲜鱼油(F)或氧化鱼油(OF)不同比例混合的7组饲料(10P,10F,6F4P,4F6P,100F,60F4P和40F6P),每个实验组设3个重复.60d饲养实验结束后,通过测定花鲈肝脏部分抗氧化酶(超氧化物歧化酶SOD,过氧化氢酶CAT和谷胱甘肽过氧化物酶GSH-Px)活力和总抗氧化能力(T-AOC),并对肝脏,肠以及肌肉进行组织学观察,研究在配合饲料中添加棕榈油替代氧化鱼油对花鲈肝脏抗氧化酶活力及其对组织结构的影响.结果表明,在含有氧化鱼油的实验组中,添加40%的棕榈油对花鲈肝脏的CAT活力以及GSH-Px活力有显著提高作用(P<0.05),对SOD活力有一定的提高效果(P>0.05),各组间总抗氧化能力差异不显著(P>0.05).新鲜鱼油组(10F,6F4P,4F6P)间抗氧化酶活力差异不显著(P>0.05).非氧化组花鲈肝脏和肌肉组织结构完整,100F组花鲈肝脏和肌肉组织呈现氧化脂肪中毒症状,添加棕榈油后(60F4P和40F6P)症状减轻,各组花鲈肠结构无明显差异.由此认为,棕榈油在花鲈饲料中部分替代鱼油是可行的,另外,在贮存不当的饲料中,后喷涂一定比例的棕榈油能对其毒性产生缓解作用.     

Effects of dietary Nannochloropsis sp. powder and lipids on the growth performance and fatty acid composition of larval and postlarval kuruma shrimp,Marsupenaeus japonicus

The current study evaluated the effects of fish oil replacement with eicosapentaenoic acid‐enriched single‐cell microalgae in the diets of larval and postlarval kuruma shrimp. Experimental diets containing different level of Nannochloropsis sp. powder (10, 40, 70 g/kg) and lipids (2, 8, 10, 14, 35, 58 g/kg) were evaluated. The substitution of fish oil with algal powder significantly improved shrimp growth compared to that in the control group, with the highest final body weight recorded at 70 g/kg in larvae and 40 g/kg in postlarvae. Larvae fed algal lipids with a dry weight percentage in the diet of greater than 10 g/kg showed significantly lower performance than those in the control group. The neutral lipids in the tissue of the postlarvae that had been fed algal lipids had an improved fatty acid profile, as the content of highly unsaturated fatty acids increased compared to that in the other groups. The content of docosahexaenoic acid increased in the tissue, indicating the possible occurrence of the metabolism and accumulation of Nannochloropsis sp. essential fatty acids. Algal powder could replace FO up to 140 g/kg in shrimp diets without compromising growth and FA profiles.     

Dietary Soy Peptide Enhances Thermotolerance and Survival of Juvenile Japanese Flounder,Paralichthys olivaceus

Soy peptide (SP), a soy protein enzymatic hydrolysate, contains bioactive substances that could be utilized as an immune‐stimulating feed ingredient. The experiment evaluated the efficacy of dietary SP on promoting growth, and enhancing tolerance and survival to heat stress in juvenile Japanese flounder, Paralichthys olivaceus. Four diets were incorporated with different levels of SP (0, 2, 5, and 10%) and a 6‐wk feeding trial ensued. Following the feeding trial, the experimental groups were subjected to heat stress to measure survival rate and heat shock protein 70s (HSP70s) in gill, liver, and skin. Fish fed diets with SP inclusion showed considerable decrease in percent weight gain. Significantly higher lethal time values to 50% mortality (LT₅₀) value were recorded for fish fed 10% SP. Moreover, LT₅₀ values of fish fed 2 and 5% SP were significantly higher compared with fish fed control diet. HSP70s produced in all the tissues were significantly highest in fish fed 10% SP. HSP70s values were significantly higher in fish fed 2 and 5% SP compared with fish fed control diet. A significant reduction in HSP70s among all groups during recovery period was also observed. These results suggest that SP can be used to enhance the immune response and survival of P. olivaceus under heat stress.     

Herpes Simplex Virus Type 1 Infection in Two Pet Marmosets in Japan

An 8-month-old common marmoset (Callithrix jacchus) was presented with tic-like symptoms, and a 2-year-old pigmy marmoset (Callithrix pygmaea) was presented with dyspnea and hypersalivation. Both monkeys died within a few days, and necropsies were performed. Histopathological examinations revealed ulcerative stomatitis with epithelial cell swelling and eosinophilic intranuclear inclusion bodies in the oral epithelium of both cases. In the central and peripheral nervous systems, neuronal cell degeneration with intranuclear inclusion bodies was observed. Immunohistochemical examination using anti-herpes simplex virus type 1 antibody revealed virus antigens in both cases. Both animals had been kept as pets with limited exposure to the ambient environment except via their owners. Therefore, herpes simplex virus type-1 was probably acquired from close contact with their owners.     

Long-term fertilizer management in NERICA cultivated upland affects on soil bio-chemical properties

ABSTRACT

This study aims to characterize soil chemical properties and microbial biomass, greenhouse gas production, and organic matter dynamics in upland rice field as affected by the long-term fertilizer managements in Uganda. Soil total C (TC) and N (TN) contents were in the relatively smaller range under different fertilizer treatments, even after 20 crop seasons. However, available phosphate contents showed positive correlation with average yield of upland rice. Incubation experiments were conducted under aerobic or under flooding conditions to measure CO₂, methane, and nitrous oxide productions. After the incubation, soil samples were extracted to quantify nitrification rate for aerobic condition and ammonification rate for flooding condition. Soil microbial biomass carbon (MBC) and nitrogen were measured. Stable isotope ratio of ¹³C and ¹⁵N were also determined for the soil samples. CO₂ production potential under aerobic condition was higher than the flooding condition. The qCO₂ (CO₂/MBC) in the treatment applied with compost tended to be higher than the other treatments. Positive correlation between nitrous oxide production and nitrification was found. The delta ¹³C values of the soil samples indicated that the effect of C4 plants before rice cultivation still remained, while the contribution of biological N₂ fixation was little according to delta ¹⁵N values. These results indicate that soil microbial biomass in upland rice field of the long-term fertilizer experiment in Uganda was characterized with higher qCO₂. Greenhouse gas production was affected by fertilizer management, while soil organic C before the long-term experiment still remained in the experiment.     

Identification and validation of a quantitative trait locus associated with wheat yellow mosaic virus pathotype I resistance in a Japanese wheat variety

Yellow mosaic disease, caused by wheat yellow mosaic virus (WYMV), is one of the most serious diseases of winter wheat (Triticum aestivum L.) in Japan. The three pathotypes of WYMV are distributed in different geographical areas: pathotype I is found mainly in western and central Japan (Kanto), pathotype II in northern Japan (Tohoku and Hokkaido) and pathotype III on the southern island of Japan (Kyushu). A total of 246 doubled‐haploid (DH) lines, derived from a cross between ‘Yumechikara’ (resistant) and ‘Kitahonami’ (susceptible), were evaluated for 2 years for their resistance to WYMV pathotype I. A single major quantitative trait locus, Q.Ymym, mapping to chromosome 2D was associated with resistance to pathotype I in ‘Yumechikara’. This is the first time a QTL responsible for pathotype I resistance has been identified. Fine mapping of Q.Ymym indicated that it was on a tight linkage block originating from ‘Yumechikara’, and the markers associated with this block will accelerate the development of varieties resistant to WYMV pathotype I.     

Energy budget of the Japanese flounder Paralichthys olivaceus (Temminck & Schlegel) larvae fed HUFA-enriched and non-enriched Artemia nauplii

The energy budget of the Japanese flounder Paralichthys olivaceus (Temminck & Schlegel) larvae fed enriched (EA) and non‐enriched (NEA) Artemia nauplii was determined by equating energy intake (EI) with the summation of energy channelled to faeces (F), metabolism (M), excretion (U) and growth (G). Larvae (21 days post hatching, 2.2 mg mean wet wt) were reared in six 80‐L circular tanks with three replicates of 160 larvae per tank and fed EA and NEA for 20 days. EI was calculated from the energy content of consumed nauplii, M from the summation of energy for routine, feeding and active metabolisms, U from ammonia excretion and G from energy gained based on weight gain, while F was the difference between EI and the total of other components. The heat increment of larvae was calculated from the difference of O₂ consumption at post‐prandial and routine conditions. Except for G and F, variables were correlated to the dry body weight (W) of larvae in a power function: Y=aW^b. Coefficients a and b were estimated by regression after a logarithmic transformation of the raw data. Overall, growth and survival rates of the larvae fed EA were higher than those fed NEA. For a larval flounder growing from 2 to 20 mg wet wt, the ingested energy was partitioned as follows: 22.8% to faecal loss, 38.3% to metabolism, 1.5% to urinary loss and 37.4% to growth for the EA group, whereas 35.4% to faecal loss, 28.4% to metabolism, 1.3% to urinary loss and 34.9% to growth for the NEA group. Gross conversion and assimilation efficiencies were higher, but the net conversion efficiency was lower in EA‐fed larvae than NEA‐fed larvae. This study suggests that the higher growth and survival rates of the EA‐fed group compared with the NEA‐fed group were attributed to their higher intake of essential fatty acids, higher metabolism and lower energy loss of faeces.     

Vitamin C requirement of kuruma shrimp postlarvae, Marsupenaeus japonicus (Bate), using l-ascorbyl-2-monophosphate-Na/Ca

l ‐ascorbyl‐2‐monophosphate‐Na/Ca (AMP‐Na/Ca) was used as a vitamin C source to investigate the ascorbic acid (AsA) requirements on growth performance and stress resistance of the post‐larval kuruma shrimp, Marsupenaeus japonicus. Purified carrageenan‐microbound diets with six levels of AMP‐Na/Ca, AsA equivalent to 0, 20, 56, 87, 759 and 1697 mg kg^?1 diet were fed to triplicate groups of M. japonicus (mean initial weight 16±0.3 mg) for 30 days. The diets with AsA 0, 20 and 56 mg kg^?1 showed high cumulative mortality after 10 days of feeding. After the 30‐day trial, the shrimp fed these diets had significantly lower survival and weight gain (WG, %) than those fed the 87, 759 and 1697 mg AsA kg^?1 diets. Specific growth rate and individual dry weight showed the same pattern as WG (%). There were no significant differences in growth performance among the groups fed the AsA levels at 87, 759 and 1697 mg kg^?1 at the termination of feeding trial. Broken‐line regression analysis indicated that 91.8 mg AsA kg^?1 in the diet was the optimum for post‐larval shrimp. On the other hand, dietary level of more than 800 mg AsA kg^?1 was needed to ensure high resistance to stressful conditions such as osmotic and formalin stressors.