Dicyema sphyrocephalum (Phylum Dicyemida: Dicyemidae) isolated from Korean common octopus Callistoctopus minor in Korea

BackgroundDicyemids are parasites found in the renal sac of cephalopods. The first species of dicyemid was found from kidneys of the Korean common octopus Callistoctopus minor.ObjectivesThis study aimed to identify the dicyemid and investigate the effect on renal sac of host.MethodsIn this study, we compared the morphological characteristics of isolate to dicyemids (Dicyema sphyrocephalum, Dicyema clavatum, and Dicyema dolichocephalum) reported from C. minor in Japan. We compared the 18S ribosomal RNA (rDNA) and cytochrome c oxidase subunit I (COI) sequences of isolate to the sequences of D. shyrocephalum and D. clavatum. The infected octopuses renal tissues were histologically compared with the tissues of uninfected individuals.ResultsThe morphological characteristic of this isolated species corresponds to D. sphyrocephalum. The sequences similarities of 18S rDNA and COI gene of isolate are 99.7% and 98.1% with D. sphyrocephalum. We observed morphological changes in the epithelia folds of kidney at the dicyemids attached areas.ConclusionsThe present study identified the isolate as D. sphyrocephalum and this is the first report of dicyemid species from Republic of Korea. Further studies on the effects of dicyemids on growth and health status of cephalopods will be needed.     

Sequence variation at a microsatellite locus (XGWM261) in hexaploid wheat (Triticum aestivum) varieties

The wheat microsatellite XGWM261 is of interest to wheat breeders because of its linkage to a commercially significant reduced height gene (Rht8). Previous studies have indicated that there are three major alleles at the XGWM261 locus and that the majority (90%) of varieties are homozygous, generating PCR products of 192,174, or 165 bp. As a preliminary investigation of heterozygosity and sequence variation at the XGWM261 locus in Australian wheat varieties, we cloned and sequenced PCR products from 24 hexaploid varieties of significance in Australian breeding programmes. Three major alleles of 192, 174 and 164 bp were found, but a165 bp allele was not detected. Prior genotyping via electrophoretic methods had indicated that 2 of the 24 (8%) varieties were heterozygous. Our results indicate that 6 varieties (25%) carry 2 or more of the major alleles. It is not clear whether this results from heterozygosity within individual seeds, or from heterogeneity of breeding stocks. With respect to the microsatellite region itself, we found that the 174 bp and 164 bp alleles actually represent (CT)₁₁AG and (CT)₆AG motifs (respectively) rather than(CT)₁₂ and (CT)₇. This finding has diagnostic potential. A further 2 varieties also carry an interrupted (CT)_nCC(CT)_n microsatellite not previously recorded. It is unclear whether this represents a separate allelic lineage or is simply the result of replication error. This revised version was published online in July 2006 with corrections to the Cover Date.     

Extraction and Activation of Wheat Polyphenol Oxidase by Detergents: Biochemistry and Applications

Polyphenol oxidases (PPOs) from several plant species, including wheat, have been implicated in undesirable brown discolorations of food products. It has been demonstrated that these enzymes are often present in a latent form or are membrane‐associated, necessitating detergent or other treatments to obtain fully active preparations. Here, the influence of different detergents on wheat meal and flour PPOs was investigated. Extraction in presence of 50 mM SDS led to a 5‐ to 15‐fold increase in PPO activity, making quantitative assays in flour from low‐PPO lines more robust. Among a series of additional nonionic, anionic, and cationic detergents tested, only n ‐lauroylsarcosine increased extractable PPO activity to a degree comparable to that of SDS. Additional experiments suggested that a large fraction of wheat meal PPOs may be membrane‐associated and that SDS is able to activate PPOs extracted from high‐activity but not from low‐activity wheat lines. PPO activities assayed after SDS extraction of meal and flour were highly correlated with each other and with activity determined in whole (intact) kernels in absence of SDS. Correlation coefficients between PPO activities measured with all these methods and noodle brightness were about equal, indicating that activities assayed after SDS extraction are useful for germplasm screening and quality prediction.