Characterization of ethylene biosynthesis and its regulation during fruit ripening in kiwifruit,Actinidia chinensis ‘Sanuki Gold’

Ethylene biosynthesis in kiwifruit, Actinidia chinensis ‘Sanuki Gold’ was characterized using propylene, an ethylene analog, and 1-methylcyclopropene (1-MCP), an inhibitor of ethylene perception. In fruit harvested between a young stage (66 days after pollination) (DAP) and an early commercial harvesting stage (143 DAP), 2 days of exposure to propylene were sufficient to initiate ethylene biosynthesis while in fruit harvested at commercial harvesting stage (154 DAP), 4 days of propylene treatment were required. This observation suggests that response of ethylene biosynthesis to propylene treatment in kiwifruit declined with fruit maturity. Propylene treatment resulted in up-regulated expression of AC-ACO1, AC-ACO2, AC-SAM1 and AC-SAM2, prior to the induction of AC-ACS1 and ethylene production, confirming that AC-ACS1 is the rate limiting step in ethylene biosynthesis in kiwifruit. Treatment of fruit with more than 5 μL L^?1 of 1-MCP after the induction of ethylene production subsequently suppressed ethylene production and expression of ethylene biosynthesis genes. Treatment of fruit with 1-MCP at harvest followed with propylene treatment delayed the induction of ethylene production and AC-ACS1 expression for 5 days. These observations suggest that in ripening kiwifruit, ethylene biosynthesis is regulated by positive feedback mechanism and that 1-MCP treatment at harvest effectively delays ethylene production by 5 days.     

Effect of intravenous injection of acetate on the pancreas of sheep

The effect of an intravenous injection of acetate on plasma insulin and glucagon concentration was examined in conscious sheep. Sodium acetate (312 to 5000 mumol kg-1 bodyweight) injection increased plasma insulin concentrations in a dose-dependent manner. Plasma glucagon concentration was not affected by doses up to 1250 mumol kg-1. Doses of 2500 and 5000 mumol kg-1 produced significant increases (P less than 0.05), but not in a dose related manner. The results of this study indicate that the receptive mechanism of the A cell in the sheep pancreas to acetate might be different from that of the B cell.     

Improved survival of vitrified in vivo-derived porcine embryos

An efficient cryopreservation protocol for porcine morulae was investigated with three types of vitrification having different cooling rates (Exp. 1). Survival of embryos vitrified after removal of cytoplasmic lipid droplets was also examined by means of the minimum volume cooling (MVC) method (Exp. 2). In Exp. 1, the morula stage embryos were vitrified with a 0.25 ml plastic straw (ST-method), gel loading tip (GLT-method) and the MVC-method, respectively, and stored in liquid nitrogen after which they were warmed in sucrose solutions with cryoprotectants being subsequently removed in a stepwise manner. In Exp. 2, morulae were centrifuged with 7.5 microg/ml cytocharasin B at 12000 x g for 20 min to polarize the cytoplasmic lipid droplets that were then removed from the embryos by micromanipulation (delipation). Both those delipated at the morula stage and the intact embryos at the morula to blastocyst stages were vitrified by the MVC-method. In vitro survival of the vitrified embryos was assessed in both experiments by culturing in NCSU-23 + 10% FCS for 48 h. In vitro developments of vitrified embryos after warming to blastocysts were 20% (6/30) for the ST-method, 39% (18/46) for the GLT-method, and 60% (26/43) for the MVC-method. Embryo survival was further improved by vitrification after delipation (95%, 35/37) compared to intact vitrified morulae (24/42, 57%, P<0.001) and blastocysts (23/31, 74%, P<0.05). Moreover, the number of cells in blastocysts (92 +/- 25) derived from the delipated-vitrified morulae was comparable to those derived from intact control non-vitrified embryos (103 +/- 31). Our results demonstrate that vitrified porcine morulae have the highest survival when using the MVC-method in conjunction with delipation.     

Transition of cell numbers in bovine preimplantation embryos: in vivo collected and in vitro produced embryos

The total cell numbers (TCNs) of bovine embryos collected from superovulated donors (VIVO embryos) were counted 0-9 d after ovulation to quantify the developmental process. Using numerical analysis of embryo development, we also compared the developmental process of VIVO embryos, in vitro-fertilized (IVF) embryos and nuclear transfer (NT) embryos obtained from enucleated oocytes and blastomere nuclei. The TCNs of embryos were measured using the air-dry method. Cleavage divisions (CD) of the embryos were obtained using logarithmic transformation of the TCN. The TCN of the VIVO embryos increased significantly (P<0.001) with time. The relationship between the CD of the VIVO embryos at 0-9 d after ovulation and age in days was described by a linear equation with a high correlation (y=1.03x+0.16, r=0.99), showing that CD occurs about once each day for all blastomeres. However, compared to the VIVO embryos, the TCN of the IVF embryos did not increase from 3-4 d nor after 7 d; the TCN of the NT embryos did not increase after 7 d (P>0.05). The results suggest a delay in development at these developmental stages. The slopes of regression lines of the IVF and NT embryos were significantly (P<0.001) smaller, indicating that quantification of the developmental process of VIVO embryos according to TCN and CD would be useful as criteria for numerical evaluation of the developmental process of bovine in vitro produced embryos.     

Economic evaluation of artificial insemination of sex‐sorted semen on a Brown Swiss dairy farm—A case study

Artificial insemination using sex‐sorted semen is employed to efficiently increase the number of female dairy calves born. Previous studies have determined that using sex‐sorted semen is beneficial to improve the management, but the mechanism by which it increases cattle numbers through objective indices of breeding remains unclear. This study focused on a Brown Swiss cattle herd in which frozen female sex‐sorted semen was systematically employed to increase the number of cattle. We analyzed the correlation between the increase in the number of cattle and the screening accuracy of sex‐sorted semen, measuring indices such as pregnancy rate and birth rate of female calves. Study revealed that: (1) production cost for female calves is influenced by the pregnancy rate, rate of female calves, and using sex‐sorted semen is less expensive than using nonsorted semen; (2) improvements in screening accuracy nearly doubled the number of cows and tripled the number of heifers in 5 years; and (3) use of sex‐sorted semen improved milk quality. The pregnancy rate was lower when sex‐sorted semen was used, but the birth rate of heifers was improved. Results suggest that artificial insemination using sex‐sorted semen is beneficial because it economically produces offspring to increase the herd.     

Detection and molecular characterization of porcine kobuvirus in piglets in 2009–2013 in northern Thailand

Tropical Animal Health and Production - A total of 636 fecal samples collected from piglets with and without diarrhea during 2009 to 2013 were tested for porcine kobuvirus by RT-PCR. From a total...     

Vitrification for bovine embryos with low‐quality grade

This study was conducted to examine the utility of vitrification for bovine embryos with low‐quality grade, and simple cryoprotectants dilution method for practitioners. In Experiment 1, survival of frozen embryos was compared with that of vitrified embryos using minimum volume cooling (MVC). Then, vitrified embryos were used to confirm the optimum sucrose concentration in Experiment 2. The survival rates of embryos that had been vitrified following diluted cryoprotectants with the one‐step in‐straw method were compared with those of fresh control embryos in Experiment 3. Frozen‐thawed or vitrified‐warmed blastocysts were cultured with TCM‐199 supplemented with 100 μmol/L beta‐mercaptoethanol +5% fetal bovine serum at 38.5°C in an atmosphere of 5% CO₂ in air, their survival after 24 hr were compared. The development to term of fair quality in vivo embryos after vitrification was examined in Experiment 4. Results show that survival rates of frozen‐thawed embryos were lower (p < .05) than that of vitrified‐warmed ones. When vitrified embryos were warmed in 0.3 mol/L sucrose in straws, their survival rate was 100%. The total cell numbers of vitrified‐warmed embryos were comparable to those of fresh control embryos. The six calves from 13 vitrified embryos were delivered in Experiment 4. These results indicate that MVC vitrification following one‐step cryoprotectants dilution is utilized to preserve low‐quality bovine embryos.     

Antimicrobial activity of melanoidins against Escherichia coli is mediated by a membrane-damage mechanism

Melanoidins are brown polymeric material formed during thermal processing of food and widely distributed in the Western diet. Three water-soluble fractions were isolated from both commercial coffee and biscuit by sequential ultrafiltration steps (3 and 10 kDa cutoff). Biscuits were enzymatically digested to solubilize the protein-linked melanoidin fraction. Antimicrobial activity of melanoidins was evaluated against a Gram-negative reference pathogenic bacterium (Escherichia coli). The high-molecular-weight fraction of water-soluble melanoidins (>10 kDa) exerted the highest antimicrobial activity. The mechanism of action was further investigated by cell integrity and outer- and inner-membrane permeabilization assays. At the minimum inhibitory concentration, melanoidins provoked irreversible cell membrane disruption, which was independent of the bacterial transmembrane potential. Results indicate that water-soluble melanoidins killed pathogenic bacteria strains ( E. coli) by causing irreversible changes in both the inner and outer membranes. Likely, it allows for interference with biosynthetic processes, such as the inhibition of nutrient transport and macromolecular precursors.     

Genetic diversity and novel combinations of G4P[19] and G9P[19] porcine rotavirus strains in Thailand

Several epidemiological studies reported the detection of rotavirus strains bearing unusual combinations of genetic background of human and porcine rotaviruses. This observation supports the hypothesis of interspecies transmission of rotaviruses in humans and pigs. The aims of this study were to investigate the genotypes and molecular characteristics of rotaviruses in piglets with diarrhea in several farms from two provinces in Thailand. A total of 207 fecal specimens collected from diarrheic piglets were screened for the presence of groups A, B, and C rotaviruses. Group A rotaviruses were detected in 41 out of 207 (19.8%) fecal specimens tested. A wide variety of G-P combination rotavirus strains were detected in this study. The G4P[6] was identified as the most prevalent genotype (39.0%), followed by G4P[23] (12.2%), G3P[23] (7.3%), G4P[19] (7.3%), G3P[6] (4.9%), G3P[13] (4.9%), G3P[19] (4.9%), G9P[13] (4.9%), G9P[19] (4.9%), G5P[6], and G5P[13] each of 2.4%. Furthermore, G5 and G9 in combinations with P-nontypeable strains were also found at each consisting of 2.4% (n = 1) of the collection. It was interesting to note that among diversified porcine rotavirus strains, novel combinations of G4P[19] and G9P[19] strains were detected for the first time in this study. Nucleotide sequences of VP4 and VP7 of these strains were closely related to human rotaviruses reported previously. The data implies that these porcine rotaviruses were probably generated in nature from the reassortment between the viruses of human and porcine origin. This study provides valuable epidemiological information and molecular characteristics of porcine rotaviruses circulating in piglets with diarrhea in northern Thailand.