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.     

Genetic association between GHSR1a 5′UTR‐microsatellite and nt‐7(C>A) loci and growth and carcass traits in Japanese Black cattle

We carried out a genetic association study between five nucleotide polymorphisms (5′UTR microsatellite ((TG)_n), nt‐7(C>A), L24V, DelR242 and Intron 1 microsatellite) of the GHSR1a gene and growth and carcass traits in 1285 steers sired by 117 Japanese Black bulls in a progeny testing program. We report herein, a significant association between the 5′UTR microsatellite and nt‐7(C>A) loci and growth and carcass traits. We also propose a translational hypothesis that the association is due to differences in the secondary structure of GHSR1b mRNA (the non‐spliced type with the 5′UTR microsatellite) among the GHSR1a gene haplotypes. Furthermore, we predicted the potential increase in profitability due to increased carcass weight in cow‐calf fattening enterprises through planned matings based on DNA testing of the 5′UTR microsatellite. Statistical analysis revealed that the 5′UTR microsatellite locus had a significant additive effect on carcass weight (CW) and average daily gain (ADG), but not on beef marbling score (BMS). One of the four major microsatellite alleles (19‐TG allele) with an allele frequency of 0.145, had a significantly (P < 0.0007) desirable effect on CW and ADG. We concluded that the 19‐TG allele could potentially be economically useful nucleotide markers for growth and carcass traits in Japanese Black cattle.     

Ultrastructural study on the morphological changes in indigenous bacteria of mucous layer and chyme throughout the rat intestine

Indigenous bacteria in the alimentary tract are exposed to various bactericidal peptides and digestive enzymes, but the viability status and morphological changes of indigenous bacteria are unclear. Therefore, the present study aimed to ultrastructurally clarify the degeneration and viability status of indigenous bacteria in the rat intestine. The majority of indigenous bacteria in the ileal mucous layer possessed intact cytoplasm, but the cytoplasm of a few bacteria contained vacuoles. The vacuoles were more frequently found in bacteria of ileal chyme than in those of ileal mucous layer and were found in a large majority of bacteria in both the mucous layer and chyme throughout the large intestine. In the dividing bacteria of the mucous layer and chyme throughout the intestine, the ratio of area occupied by vacuoles was almost always less than 10%. Lysis or detachment of the cell wall in the indigenous bacteria was more frequently found in the large intestine than in the ileum, whereas bacterial remnants, such as cell walls, were distributed almost evenly throughout the intestine. In an experimental control of long-time-cultured Staphylococcus epidermidis on agar, similar vacuoles were also found, but cell-wall degeneration was never observed. From these findings, indigenous bacteria in the mucous layer were ultrastructurally confirmed to be the source of indigenous bacteria in the chyme. Furthermore, the results suggested that indigenous bacteria were more severely degenerated toward the large intestine and were probably degraded in the intestine.     

稻田田埂植物的生物多样性

 在浙江安吉两个村对利用不同污染程度水源进行灌溉的稻田田埂植物进行了调查。利用未受工业污染的水灌溉的禹山坞稻田田埂植物种数高于受工业废水污染的城北村。在相同类型植物群落中, 禹山坞稻田田埂的植物种总重要值Iv(t)显著高于城北村,两村的田埂植物生物多样性指数也存在类似的变化趋势。不同类型植物群落的生物多样性参数差异极为显著, 矮秆植物占优势群落的植物种数、植物种总重要值和生物多样性指数(H')显著高于高秆植物占优势群落和外来植物占优势群落。应重视防除外来植物空心莲子草, 控制高秆植物和保护矮秆植物。     

Polyoxin Resistance of Reddish Brown Laboratory Mutants of Cochliobolus heterostrophus

Six reddish brown polyxin-resistant mutants of Cochliobolus heterostrophus were isolated after ethyl methanesul-phonate and N-nitroquinoline oxide mutageneses followed by selection on polyoxin. All the mutants were highly resistant to polyoxin (MIC > 1600 μg/ml). When mutants were crossed with the wild-type strain, all crosses had a 1 : 1 ratio of mutant (reddish brown pigmentation and polyoxin resistance) : wild type (non-reddish brown pigmentation and polyoxin sensitivity), indicating that the phenotypes in these strains were due to alteration at a single gene locus in each strain. Allelism tests revealed the existence of two loci, Pol2 and Pol5. The results of the crossing and mutation-rate studies suggest that the each gene was pleiotropic for the reddish brown color and polyoxin resistance. Received 19 September 2001/ Accepted in revised form 25 December 2001