Cryoprotective effects of shrimp head protein hydrolysate on gel forming ability and protein denaturation of lizardfish surimi during frozen storage

ABSTRACT:   The effects of shrimp head protein hydrolysate (SHPH) from three species of shrimp (northern pink shrimp [ Pandalus eous ], endeavour shrimp [ Metapenaeus endeavouri ], black tiger shrimp [ Penaeus monodon ]) on gel forming ability and protein denaturation of lizardfish surimi during frozen storage at −25°C were evaluated. The quality of lizardfish surimi with 5% (dried matter) of any of the three SHPH or sodium glutamate (Na-Glu) was examined in terms of gel strength, whiteness, Ca-ATPase activity and the amount of unfrozen water, comparing with those of surimi without additive as the control. The residual Ca-ATPase activity and gel strength of surimi with SHPH were higher than those of the control throughout 180 days of frozen storage, regardless of shrimp species. The highest effect was found in surimi with Na-Glu. The gel strength and Ca-ATPase activity found a high positive correlation. The addition of SHPH to surimi also increased the amount of unfrozen water by approximately 1.29–1.36 fold higher than the control, however kamaboko gels of the control was significantly whiter. From these results, freeze-induced denaturation of lizardfish muscle protein could be lessened by the addition of SHPH, resulting in a high gel strength and Ca-ATPase activity.     

Tetrahydrofolate-dependent vanillate and syringateO-demethylation links tightly to one-carbon metabolic pathway associated with amino acid synthesis and DNA methylation in the lignin metabolism ofSphingomonas paucimobilis SYK-6

Sphingomonas paucimobilis SYK-6 strain can degrade various lignin-related compounds. In the lignin metabolic pathway of this bacterium, vanillate and syringate are demethylated by the tetrahydrofolate (THF)-dependentO-demethylation system, which requires the enzymatic function of LigH. Upstream of theligH gene is the 5,10-methylene-THF reductase gene. Its gene product was essential for one-carbon metabolism involved in the amino acid synthesis and DNA methylation in all organisms. When themetF gene was inactivated in the genome of SYK-6, the resultant mutant, DLmetF, could not grow on vanillate and syringate as a sole carbon source. Furthermore, DLmetF showed significant accumulation of methyl-THF as a result of vanillate and syringateO-demethylation. We report here that THF-dependent vanillate and syringateO-demethylation links tightly to the one-carbon metabolic pathway that is associated with amino acid synthesis and DNA methylation, and the methyl group is the sole one-carbon source inS. paucimobilis SYK-6.     

Production of Functional Gametes from Cryopreserved Primordial Germ Cells of the Japanese Quail

The Japanese quail (Coturnix japonica) is a valuable bird as both an experimental animal, for a wide range of scientific disciplines, and an agricultural animal, for the production of eggs and meat. Cryopreservation of PGCs would be a feasible strategy for the conservation of both male and female fertility cells in Japanese quail. However, the effects of freeze-thaw treatment on viability, migration ability and germline transmission ability of quail PGCs still remain unclear. In the present study, male and female PGCs were isolated from the blood of 2-day-old embryos, which were cooled by slow freezing and then cryopreserved at –196 C for 77–185 days, respectively. The average recovery rate of PGCs after freeze-thawing was 47.0%. The viability of PGCs in the frozen group was significantly lower than that of the control group (P<0.05) (85.5% vs. 95.1%). Both fresh and Frozen-thawed PGCs that were intravascularly transplanted into recipient embryos migrated toward and were incorporated into recipient gonads, although the number of PGCs settled in the gonads was 48.5% lower in the frozen group than in the unfrozen control group (P<0.05). Genetic cross analysis revealed that one female and two male recipients produced live progeny derived from the frozen-thawed PGCs. The frequency of donor-derived offspring was slightly lower than that of unfrozen controls, but the difference was not significant (4.0 vs. 14.0%). These results revealed that freeze-thaw treatment causes a decrease in viability, migration ability and germline transmission ability of PGCs in quail.     

Effect of cellulase supplementation in low-crude protein diets on performance, nitrogen excretion, fat deposition, hepatic lipogenic and lipolytic enzyme activity in broilers

1. Two experiments were conducted to investigate the effect of dietary enzyme supplementation of a low-protein diet on performance, nitrogen excretion, fat deposition, hepatic lipogenic and lipolytic enzyme activity in 7-21- (Experiment 1) and 21-42-d-old (Experiment 2) male broiler chicks. 2. Chicks were given diets containing 210 g (Experiment 1) or 170 g (Experiment 2) crude protein (CP)/kg (Control), amino acid-fortified diets 190 g (Experiment 1) and 150 g (Experiment 2) CP/kg (Low-protein), and a low-protein diet supplemented with 1000 U/kg of cellulase. 3. In Experiment 1, growth performance and abdominal fat deposition were not affected by dietary treatments, and birds given low-protein diets excreted less nitrogen. The activities of hepatic lipogenic and lipolytic enzymes were not different among the three dietary groups. 4. In Experiment 2, the dietary treatment did not affect growth performance or abdominal fat weight. Nitrogen excretion was significantly lower in chicks given the 150 g/kg CP diet than those on the 170 g/kg CP diet; however, nitrogen retention was no different among the treatments. Dietary CP and enzyme supplementation did not significantly affect hepatic enzyme activities. 5. These results suggest that CP content in the broiler diet can be reduced by 20 g/kg without lowering performance by the supplementation of crystalline amino acids, and can reduce nitrogen excretion by about 25%. Cellulase supplementation of a low-CP diet slightly lowered abdominal fat deposition; however, it did not significantly affect hepatic lipogenic and lipolytic enzyme activity.     

In Search of Optimum Institutions for Forest Management

There is a variety of forest management institutions ranging from state management to community and private management. This article attempts to identify the conditions under which one institution outperforms the others in the efficiency of forest management based on a review of the literature, empirical evidence on the dominant forest management institutions, and theoretical arguments. In conclusion, we argue that the community management system performs best for nontimber forests, whereas a mixed management system, in which forest protection is carried out communally and tree management is carried out individually, is likely to work best for timber forests.     

Influence of intergeneric/interspecies mitochondrial injection; parthenogenetic development of bovine oocytes after injection of mitochondria derived from somatic cells

Interspecies/intergeneric mitochondrial heteroplasmy can occur in interspecies/intergeneric hybrid embryos or following nuclear transfer. In the present study, intergeneric buffalo (Bubalus bubalis) mitochondria (WB-mt) or interspecies murine (Mus spretus) mitochondria (M-mt) were injected into bovine (Bos taurus) oocytes, and the subsequent embryonic development was characterized. Fibroblast mitochondria (WB-mt or M-mt) were microinjected into in vitro matured bovine oocytes followed by oocyte activation by a combination of electrical stimulation and 6-dimethylaminopurine treatment. After seven days of culture, embryo development was evaluated. The copy number of specific mtDNA populations (introduced and native mtDNA) from heteroplasmic oocytes was estimated using real-time PCR. The results illustrated that oocytes injected with either WB-mt or M-mt can develop to the blastocyst stage (20.6% and 19.6%). Cleavage division rates and development to the morula stage in oocytes injected with WB-mt were lower (76.2% and 45.9%, respectively) in comparison with uninjected oocytes (89.2% and 59.1%, respectively) (P<0.05). However, no differences were found in comparing M-mt injected oocytes and controls (P>0.05). An increase in bovine mtDNA copy number was observed at the expanded blastocyst stage of injected embryos (P<0.01), while the number of injected mtDNA was stable throughout development. This study demonstrates that interspecies/intergeneric mitochondrial injected bovine oocytes have the ability to develop to the blastocyst stage after parthenogenetic activation and that injected mtDNA was neither selectively destroyed nor enhanced through development. Moreover, injected intergeneric mitochondria had a demonstrated influence on bovine parthenogenetic development and mtDNA replication.     

Collie eye anomaly in Hokkaido dogs: case study

Objective To describe a Hokkaido dog, one of the traditional Japanese breeds that was affected by Collie eye anomaly (CEA), and to report the genotype of this dog and the Hokkaido dog allelic frequency of the CEA‐associated mutation. Case A nine‐month‐old intact female Hokkaido dog without any obvious visual disturbance was diagnosed ophthalmoscopically with CEA. Severe choroidal hypoplasia was observed in the bilateral temporal area adjacent to the optic nerve head, appearing as whitish areas. Therefore, the dog was suspected of possessing the CEA‐associated mutation that was previously reported as an intronic 7.8‐kilo base deletion in the canine NHEJ1 gene. Procedures SYBR Green‐based real‐time PCR with a melting curve analysis, conventional PCR with agarose gel electrophoresis, and direct DNA sequencing were carried out to determine the genotype of the dog. Furthermore, a preliminary genotyping survey was carried out in 17 Hokkaido dogs from three kennels using the real‐time PCR method, and the pedigree relationships were analyzed using their pedigree papers. Results The Hokkaido dog affected by CEA was proven to possess the CEA‐associated mutation. Of these 17 Hokkaido dogs, 12 dogs were heterozygous carriers and five dogs were affected by this mutation. The preliminary genotyping survey and pedigree analysis demonstrated that the allelic frequency of the CEA‐associated mutation is very high in Hokkaido dogs. Conclusion These data suggest that the Hokkaido breed is highly susceptible to CEA because of the known CEA‐associated mutation much like the Collie‐related breeds.     

P-19 Sporotrichosis in São Paulo (Brazil): clinical and epidemiological features

The aim of this study was to determine the in vitro antifungal activity of several antifungal drugs (posaconazole, nystatin, miconazole and clotrimazole) against Malassezia pachydermatis with microdilution and agar dilution techniques. Malassezia pachydermatis isolates were obtained from the skin and ears of dogs. Tests on solid media were performed using 25-well Petri dishes (2 mL/well containing Sabouraud's dextrose agar and diluted antifungal drug) inoculated with 5 μL suspensions of M. pachydermatis . Microtitre broth dilution used 96-well microtitre plates containing Sabourauds dextrose broth and appropriate dilutions of antifungal drugs, inoculated with 10 μL standard suspensions of M. pachydermatis . Plates were inoculated in duplicate and incubated at 30°C for 5 days and growth assessed. The four antifungal drugs were tested in 10 dilutions (4.0-0.007 μg/mL for posaconazole, and 32--0.06 μg/mL for clotrimazole, miconazole and nystatin). Results obtained for 83 strains of M. pachydermatis and a control reference strain (CBS 1879) exhibited the same pattern. Results of the MIC between microtitre and agar methodologies showed no significant differences (≤ 2-fold) across all drugs. For both solid and liquid methods, posaconazole was the most effective antifungal drug of the four tested with MIC₉₀ of 1–2 μg/mL for posaconazole, 16–32 μg/mL for clotrimazole, and ≥ 32 μg/mL for miconazole and nystatin.
Funding: Schering-Plough.     

Characterization of pseudorabies virus glycoprotein B expressed by canine herpesvirus

A recombinant canine herpesvirus (CHV) which expressed glycoprotein B (gB) of pseudorabies virus (PrV) was constructed. The antigenicity of the PrV gB expressed by the recombinant CHV is similar to that of the native PrV. The expressed PrV gB was shown to be transported to the surface of infected cells as judged by an indirected immunofluorescence test. Antibodies raised in mice immunized with the recombinant CHV neutralized the infectivity of PrV in vitro. It is known that the authentic PrV gB exists as a glycoprotein complex, which consists of gBa, gBb and gBc. In MDCK cells, PrV gB expressed by the recombinant CHV was processed like authentic PrV gB, suggesting that the cleavage mechanism of PrV gB depends on a functional cleavage domain from PrV gB gene and protease from infected cells.