Evaluation of ingredient effects on extruded starch-based foams using a supersaturated split-plot design

The aim of this study was to use a supersaturated split-plot design to identify the significant effects of ten ingredients, each at two levels, and two levels of screw speed on selected properties of starch-based packaging foams. Supersaturated designs are special types of fractional factorial designs that allow for evaluating many factors with a minimal amount of experimental material. Rice starch foams were prepared with a twin-screw extruder. The ingredients used were α-cellulose (fiber), potato starch, poly(lactic acid), polystyrene, glycerol, sodium chloride, talc, sodium bicarbonate, citric acid and moisture content of the feed. The properties studied were radial expansion ratio, unit density, bulk spring index, bulk compressibility and Young's modulus. The results showed that the ingredients identified to have significant effects on the properties were the high levels of talc, citric acid, moisture content and the low level of fiber. Low screw speed was found to have greater effect on the properties of the foams than did the high screw speed. It was concluded that the supersaturated split-plot design was successful in identifying the significant ingredients and screw speed that should be used to further investigate the extrusion of starch-based packaging foams.     

Effects of dietary Centella asiatica (L.) Urban on growth performance,nutrient digestibility,blood composition in piglets vaccinated with Mycoplasma hyopneumoniae

To investigate the effects of Centella asiatica (L.) on growth performance, nutrient digestibility and blood composition in piglets, 32 nursery pigs were fed 0.0, 0.5, 1.0 and 2.0% dietary C. asiatica (L.) from 15 to 90 kg BW. At 30 kg BW, nutrient digestibility was measured and at 35 kg BW piglets were vaccinated with Mycoplasma hyopneumoniae. Hematological parameters were checked at 40 and 80 kg BW. Compared with the control, growth performance was not affected. The ether extract, ash and calcium digestibility were lower at 0.5%, and dry matter, crude protein, crude fat, phosphorus and energy digestibility were lower at 1.0% (P < 0.05). On hematological values, at 40 kg hematocrit, total white blood cells, neutrophils, eosinophils, basophils, monocytes and lymphocytes were higher at the 2.0% level (P < 0.05). Most of these values except basophils and monocytes continued until at 80 kg, at which total white blood cells, neutrophils, eosinophils and lymphocytes were higher even at 1.0% (P < 0.05); neutrophil‐to‐lymphocyte ratio tended to be higher at 2.0% (P < 0.03). Cholesterol, triglycerides and antibody levels against M. hyopneumoniae did not differ except that at 40 kg the cholesterol of 0.5% was lower (P < 0.05) and M. hyopneumoniae‐specific antibodies tended to be higher with increasing levels of C. asiatica (L.) (P < 0.07). The result that C. asiatica (L.) could not improve growth performance but increased values of serum hematocrit and white blood cells, and mycoplasma immunity to M. hyopneumoniae might suggest that C. asiatica (L.) has no function to elevate body weight but has the potential to enhance innate immunity.     

Evaluation of blood adiponectin levels as an index for subacute ruminal acidosis in cows: a preliminary study

The objective of this study was to evaluate blood levels of various hormones and compounds related to energy metabolism in cows with subacute ruminal acidosis (SARA). We investigated 11 lactating cows presumed to have SARA based on duration of ruminal pH <5.6 and reticulum pH <6.3 in 2015–2016. Kraft pulp (KP) was used to supplement feed of 7 of the cows studied in an effort to reduce SARA. We continuously monitored ruminal pH and measured blood concentrations of hormones and metabolites related to energy metabolism. Blood measurements included glucose (GLU), total cholesterol (TC), free fatty acid (FFA), insulin, adiponectin (ADN), malate dehydrogenase (MDH), and lactate dehydrogenase (LDH). Additionally, we analyzed milk data (milk yield, milk fat percentage, milk protein percentage, milk urea nitrogen, and protein fat ratio) and reproduction data. The results demonstrated that ADN levels at 4 weeks post-parturition correlated with the total amount of time that the ruminal or reticulum fluid pH was under the threshold during 1 week post-parturition, as well as the numbers of days the cows were diagnosed with SARA (SARA-positive days) up to 30 days post-parturition. SARA-positive days in 2016 were higher than those in 2015. In both years, numbers of SARA-positive days for cows supplemented with KP were lower than those for cows without KP. Increased ADN levels may be a compensatory reaction to frequent SARA which modulates the inflammatory response against high LPS levels and improves insulin resistance caused by LPS. ADN may serve as an estimative index for SARA.

     

Antifreeze Peptides and Glycopeptides,and Their Derivatives: Potential Uses in Biotechnology

Antifreeze proteins (AFPs) and glycoproteins (AFGPs), collectively called AF(G)Ps, constitute a diverse class of proteins found in various Arctic and Antarctic fish, as well as in amphibians, plants, and insects. These compounds possess the ability to inhibit the formation of ice and are therefore essential to the survival of many marine teleost fishes that routinely encounter sub-zero temperatures. Owing to this property, AF(G)Ps have potential applications in many areas such as storage of cells or tissues at low temperature, ice slurries for refrigeration systems, and food storage. In contrast to AFGPs, which are composed of repeated tripeptide units (Ala-Ala-Thr)_n with minor sequence variations, AFPs possess very different primary, secondary, and tertiary structures. The isolation and purification of AFGPs is laborious, costly, and often results in mixtures, making characterization difficult. Recent structural investigations into the mechanism by which linear and cyclic AFGPs inhibit ice crystallization have led to significant progress toward the synthesis and assessment of several synthetic mimics of AFGPs. This review article will summarize synthetic AFGP mimics as well as current challenges in designing compounds capable of mimicking AFGPs. It will also cover our recent efforts in exploring whether peptoid mimics can serve as structural and functional mimics of native AFGPs.     

世界不同地理来源粳稻品种的遗传相似性研究

 【目的】探讨不同国家（或地区和组织）间粳稻选育品种的遗传相似性和遗传差异,旨在为世界各地的粳稻品种能够有效利用于水稻育种提供科学依据。【方法】利用34对SSR引物对不同地理来源包括20个国家（或地区和组织）的313份粳稻选育品种进行遗传相似性和聚类分析。【结果】共检测到198个等位基因,平均每对SSR引物检测到的等位基因数为5.8235个。RM320、RM531、RM1、RM21和RM336的等位基因数较多,分别为16、13、12、10和10个;RM320、RM336、RM286、RM531和RM21的遗传多样性指数较高,分别为2.3668、2.0041、1.9684、1.9508和1.7203。各国家（或地区和组织）粳稻选育品种的遗传相似系数变异范围为0.279～0.918,平均值为0.653。纬度和地理位置相近的国家间粳稻品种的遗传相似系数较大,基本聚为同一个类群,而纬度差异较大,地理位置较远的国家间粳稻品种的遗传相似系数较小,聚为不同类群。 【结论】粳稻品种的遗传相似性与纬度和地理位置有着密切的联系。     

Adaptation of the New Zealand Psa risk model for forecasting kiwifruit bacterial canker in Korea

Bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae (Psa), is a severe threat to kiwifruit production in Korea. An existing infection risk model from New Zealand was adopted to respond to this epidemic. Disease incidence (proportion of diseased leaves on each vine) and weather (hourly temperature, rainfall and relative humidity) data required to develop the model were collected and analysed in the study. Disease incidence data were used to modify and validate the existing model. Because the Psa risk model was originally developed in a region where the characteristic climatic conditions are completely different from those in Korea, the temperature and rainfall functions of the existing model were modified. Analyses using statistical correlation and prediction–realization tables revealed that the modified model is valid with high agreement (a correlation coefficient of 0.85 and an accuracy of 85.7%, respectively) between the observed disease incidence and simulated disease risk from the model. The model was also found to be more highly sensitive to the presence or absence of rainfall than any other weather variable inputs. Uncertainty in simulated disease risk was measured based on the level of uncertainty in temperature input from weather forecasts. Overall, these results indicate that the modified Psa risk model can be used to provide practical and applicable information for timely disease control to the kiwifruit growers in Korea.     

17beta-estradiol pretreatment prevents the global ischemic injury-induced decrease of Akt activation and bad phosphorylation in gerbils

Estradiol acts as a neuroprotective factor against ischemic brain injury. This study investigated whether estradiol modulates neuroprotective mechanism through the activation of Akt and its downstream target such as Bad in global ischemic injury. Adult female gerbils were ovariectomized and treated with estradiol prior to ischemic injury. Transient cerebral ischemia was accomplished by bilateral clipping of the common carotid artery for 5 min. Brains were collected on 1, 3, 5 day after injury. In hippocampal CA1 region of non-treated gerbils, most of neuronal cells exhibited pyknotic nuclei and showed the positive reaction of TUNEL staining on 5 day after injury. However, estradiol significantly reduced the neuronal cell death. Potential activation was measured by phosphorylation of Akt at Ser473 and Bad at Ser136 using western blot analysis. The levels of pAkt and pBad were significantly decreased in non-treated gerbils on 1-5 day after injury. However, estradiol prevents the global ischemic injury-induced decrease of pAkt and pBad. Our findings suggest that estradiol prevents cell death due to global ischemic injury and that Akt activation and Bad phosphorylation by estradiol mediated these protective effects.     

Nicotinamide prevents the down-regulation of MEK/ERK/p90RSK signaling cascade in brain ischemic injury

Nicotinamide attenuates neuronal cell death related to focal cerebral ischemic injury. This study investigated whether nicotinamide exerts a neuroprotective effect through the activation of Raf- mitogen-activated protein kinase kinase (MEK)-ERK and its downstream targets, including p90 ribosomal S6 kinase (p90RSK) and Bad. Adult male Sprague-Dawley rats were treated with nicotinamide (500 mg/kg) or vehicle 2 hr after the onset of middle cerebral artery occlusion (MCAO). Brains were collected 24 hr after MCAO. In the present study, nicotinamide significantly reduces the volume of infarct regions and decreases the number of positive cells by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining in the cerebral cortex. Nicotinamide prevents injury-induced decrease in Raf-1, MEK1/2, and ERK1/2 phosphorylation. As part of the downstream cascade, nicotinamide inhibits the injury-induced decrease in p90RSK and Bad phosphorylation. Moreover, nicotinamide prevents the injury-induced increase in cleaved caspase-3 levels. These findings suggest that nicotinamide protects neuronal cells against cerebral ischemic injury and that MEK-ERK-p90RSK cascade activation by nicotinamide contributes to these neuroprotective effects.     

Ethanol exposure suppresses survival kinases activation in adult rat testes

The present study was designed to evaluate whether ethanol suppresses survival-signaling pathways in rat testes. Ethanol (1.5 g/kg or 3 g/kg i.p., 15% v/v in saline) was administrated to adult male rats for 10 days. Ethanol treatment significantly increased the number of TUNEL-positive cells in rat testes. Potential activation was measured by phosphorylation of Akt and Erk1/2 using Western blot analysis. Ethanol decreased the levels of activated survival kinases, pAkt and pErk1/2. The phosphorylation of Bad at Ser112 and Ser136 was decreased in ethanol-treated animals in comparison to saline-treated animals. Moreover, the interaction of pBad with 14-3-3 was decreased by ethanol exposure. In conclusion, our findings suggest that ethanol induces apoptotic cell death by suppressing the activation of survival kinases and the phosphorylation of their downstream targets in rat testes.     

The effects of density on the behaviour and growth of juvenile blacklip abalone (Haliotis rubra)

The growth of juvenile abalone in aquaculture is known to be affected by density as a result of competition for food and decreases in water quality. Our results suggest that behaviour is also affected by density and this also has a significant impact on the growth of individual abalone. 1800 juveniles of Haliotis rubra were individually tagged and reared for 5 months in 12 gravity-fed tanks at two levels of density. The experimental design allowed the differentiation of the direct from the indirect effects of density. The abalone growth and distribution was monitored monthly along with the water quality. The distribution of abalone during daytime was closely related to the availability of preferred shelter space. The percentage of abalone stacked on the top of others increased with density. Preferred shelter space was characterized by low light intensity and a corner or edge for the abalone to rest against. Hides at the ends of the tanks were not occupied as much as others. Abalone were found crawling on the side of the tank during daytime when tanks were shaded. Abalone juveniles of 15–60 mm showed fidelity to their resting shelter during daytime but this fidelity was significantly reduced at the higher density. Shading of the tanks totally changed the distribution of the abalone and their daytime behaviour. Competition for shelter space reduced growth more than water quality. This revised version was published online in August 2006 with corrections to the Cover Date.