Accumulation of paralytic shellfish poisoning toxins in bivalves and an ascidian fed on Alexandrium tamarense cells

SUMMARY: Cultured cells of the dinoflagellate Alexandrium tamarense were fed to four species of bivalves and an ascidian to examine the interspecific differences in the ability to accumulate paralytic shellfish toxins. The specimens of each species were reared in the same tank. All the species ingested almost all the cells fed and became toxic. Marked individual differences in toxin accumulation was observed in all the species. However, the average amounts of accumulated toxins increased during feeding. When the animals were fed on the same amount of cells, they accumulated almost the same amounts of toxins, indicating that interspecific differences in toxin accumulation observed in nature is due to the difference in ingestion behavior of the animals under natural conditions.     

Simple and sensitive method for pyrroloquinoline quinone (PQQ) analysis in various foods using liquid chromatography/electrospray-ionization tandem mass spectrometry

Pyrroloquinoline quinone (PQQ) is believed to be an important factor for mammalian growth and development and has, therefore, been declared a vitamin by some researchers. However, this issue remains controversial, and from a nutritional viewpoint, accurate determination of PQQ levels in a variety of foods is very important. Here, we describe a simple, highly sensitive, and highly selective method for quantitative analysis of PQQ. Liquid foods or aqueous extracts of solid foods were analyzed using high-performance liquid chromatography (HPLC) combined with electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). (15)N-labeled PQQ was added to the samples as an internal standard. Quantitative analyses of PQQ were performed by multiple reaction monitoring (MRM) with LC/MS/MS. Free PQQ was detected in almost all food samples in the range 0.19-7.02 ng per g fresh weight (for solid foods) or per mL (liquid foods). This method will enable the rapid and simple determination of PQQ levels in many samples.     

Spontaneous Renal Tumors Suspected of Being Familial in Sprague-Dawley Rats

Spontaneous renal tubule tumors (RTTs), with a distinctive morphological phenotype, were present in three Sprague-Dawley rats, 1 male and 2 females, out a total of 120 animals of each sex from untreated and placebo control groups in a 2-year carcinogenicity study. One female had one carcinoma, adenoma and hyperplasia, and the other female had five adenomas and many hyperplastic lesions; the male case had one carcinoma. From these cases, a biological continuum of hyperplasia, adenoma and carcinoma could be recognized. The tumors were present in the renal cortex and appeared as solid lobulated growths with occasional central necrosis. The lobules were divided by a small amount of fibrovascular tissue. Occasionally the larger tumors contained a cystic area. Tumor cells appeared distinctive and exhibited variable amounts of eosinophilic/amphophilic and vacuolated cytoplasm. Nuclei were round to oval with a prominent nucleolus. Mitotic figures were uncommon, and no distant metastasis was noted. The tumors were seen as multiple and bilateral lesions in two animals and had no apparent relationship to chronic progressive nephropathy (CPN). Foci of tubule hyperplasia were also noted to contain the same type of cellular morphology. The morphological and biological features of these 3 cases resembled the amphophilic-vacuolar (AV) variant of RTT that has been posited to be of familial origin. This is a report of spontaneous familial renal tumors in Sprague-Dawley rats from Japan.     

Surveillance of chronic wasting disease in sika deer, Cervus nippon, from Tokachi district in Hokkaido

Surveillance of chronic wasting disease (CWD) was conducted by performing Western blot analysis of tissue samples from 136 sika deer (Cervus nippon) killed by hunters in the Tokachi district of Hokkaido Island. No prion protein (PrPSc) associated with CWD was detected in any of the samples. To assess amino acid polymorphisms of the sika deer PrP gene, nucleotide sequencing of the PrP gene was performed. The only amino acid polymorphisms detected were 3 silent mutations at nucleotide positions 63, 225 and 408. These results suggest that sika deer in the Tokachi district are genetically homogeneous, and are not infected with CWD.     

A Free Cyclotrigermenium Cation with a 2pi-Electron System

The reaction of tetrakis(tri-tert-butylsilyl)cyclotrigermene with trityl tetraphenylborate in benzene produces tris(tri-tert-butylsilyl)cyclotrigermenium tetraphenylborate [(tert-Bu3SiGe)3+BPh4-], which can be isolated as a yellow solid that is stable in the absence of air. The crystal structure of the cyclotrigermenium ion reveals a free germyl cation with a 2pi-electron system. The three germanium atoms form an equilateral triangle similar to the carbon analog, the cyclopropenium ion.     

Lignification in developing culms of bamboo <Emphasis Type="Italic">Sinobambusa tootsik</Emphasis>

Bamboos are among the largest woody grasses and grow very rapidly. Although lignin is a crucial factor for the utilization of bamboo biomass, the lignification mechanism of bamboo shoots is poorly understood. We studied lignification in the bamboo Sinobambusa tootsik during culm development. Elongation growth began in May and ended in late-June, when the lignin content was approximately half that in mature culms. Thioacidolysis analysis indicated that p-hydroxyphenyl units in lignin formed even at late stages of lignification. The syringyl/guaiacyl ratio varied during culm development. Various lignin precursors were detected in developing culms by liquid chromatography–mass spectrometry. The ferulic acid content decreased from May to June, indicating that ferulic acid was utilized in early stages of cell wall formation. Monolignol glucosides were detected at early stages of lignification, whereas the contents of monolignols, coniferaldehyde, sinapaldehyde, p-coumaric acid, and ferulic acid peaked at later stages of lignification. Therefore, lignin precursors may be supplied differentially during the lignification process. In August, the rate of lignification decreased, although the contents of various lignin precursors peaked, implying that the rate-limiting step in the cessation of lignification in bamboo is transport or polymerization of lignin precursors, rather than their biosynthesis.