Phylogenetic relationship of Alexandrium tamiyavanichii (Dinophyceae) to other Alexandrium species based on ribosomal RNA gene sequences

The phylogenetic relationship of the thecate PSP-toxin producing dinoflagellate Alexandrium tamiyavanichii Balech to other species of Alexandrium was studied based on nucleotide sequences of the ITS1, ITS2, 5.8S, 18S and 28S subunits of the ribosomal RNA gene. These are the first such sequences available for A. tamiyavanichii, which is one of the producers of paralytic shellfish poisoning toxins in tropical waters. Based on the nucleotide sequences of the 28S, 18S and 5.8S subunits of the rRNA gene, A. tamiyavanichii grouped together with A. tamarense, A. catenella and A. fundyense. More interestingly, A. tamiyavanichii was most closely affiliated to A. tamarense isolates from Thailand. This result reaffirmed conclusions from previous studies that, for the A. tamarense/fundyense/catenella species complex, geographical origin rather than morphology seems to determine genetic relatedness. Results of this study also suggest that A. tamiyavanichii most probably belongs to the same species complex. Ribosomal RNA gene sequences do not separate the PSP toxin producing from the non-producing species of Alexandrium.     

Changes in the Glutamate Release and Uptake of Cerebellar Cells in Perinatally Nicotine-Exposed Rat Pups

Cerebellar granule and glial cells were cultured from 7 day-old rat pups after pre- and post-natal nicotine treatment. Ten days later, the basal release of glutamate in the granule cells prepared from the pre- and post-natally nicotine-exposed pups was higher and lower than the controls, respectively. The N-methyl-D-aspartate-induced release of glutamate was higher in the granule cells of post-natal nicotine exposed rats. However, the nicotine-induced glutamate release was either unchanged or was lower in the granule cells of all nicotine-treated pups. The basal glutamate uptake was higher in the glial cells from those exposed pre-natally and lower in the continuously nicotine-exposed pups. The sensitivities of L-trans-pyrrolidine-2,4-dicarboxylic acid on glutamate uptake were higher in all nicotine treated groups. There was a higher number of specific [³H]dizocilpine binding sites in the pre- or continuously nicotine-exposed group. These results suggest that the cerebellar cell properties are altered after perinatal nicotine exposure and that the development of an excitatory amino acid system might be affected differently depending on the nicotine exposure time.     

Treatment with a copper-zinc chelator markedly and rapidly inhibits beta-amyloid accumulation in Alzheimer's disease transgenic mice.

Inhibition of neocortical beta-amyloid (Abeta) accumulation may be essential in an effective therapeutic intervention for Alzheimer's disease (AD). Cu and Zn are enriched in Abeta deposits in AD, which are solubilized by Cu/Zn-selective chelators in vitro. Here we report a 49% decrease in brain Abeta deposition (-375 microg/g wet weight, p = 0.0001) in a blinded study of APP2576 transgenic mice treated orally for 9 weeks with clioquinol, an antibiotic and bioavailable Cu/Zn chelator. This was accompanied by a modest increase in soluble Abeta (1.45% of total cerebral Abeta); APP, synaptophysin, and GFAP levels were unaffected. General health and body weight parameters were significantly more stable in the treated animals. These results support targeting the interactions of Cu and Zn with Abeta as a novel therapy for the prevention and treatment of AD.     

A nonsingular optimization approach to the feed rate profile optimization of fedbatch cultures

A new method to calculate the optimal feed rate profile for fedbatch culture is proposed. Instead of the usual singular control approach of taking the feed rate as the control variable, the substrate concentration profile is used as the transformed control variable to avoid the computational difficulty associated with the singular control. Thus, the problem is converted into a nonsingular optimization problem of determining the optimal substrate concentration profile subject to a constraint. The equivalent feed rate profile to match the optimal substrate concentration profile is then generated. With this method the computational difficulty associated with singular controls for high-order systems is circumvented. The proposed method is illustrated by a number of examples.     

Body mass index and relative handgrip strength are associated with the prevalence of hypertension in Korean elderly: Korean national fitness assessment in 2019

[Purpose]This study aimed to analyze the prevalence of hypertension according to the body mass index (BMI) and relative handgrip strength (RHGS) among elderly individuals in Korea. [Methods]We analyzed the data of 44,183 Korean elderly individuals over 65 years old (men: n = 15,798, age = 73.31 ± 5.04 years, women: n = 28,385, age = 72.14 ± 5.04 years) obtained from the Korean National Fitness Assessment in 2019. All the participants were categorized into three groups according to the BMI and RHGS; additionally, one-way ANOVA and logistic regression analysis were performed. [Results]Overweight (men: 1.16 odds ratio [OR] 1.06–1.26, 95% confidence interval [CI]; women: 1.15 OR, 1.07–1.23 95% CI) and obese (men: 1.54 OR, 1.42–1.66 95% CI; women: 1.44 OR, 1.36–1.53 95% CI) elderly individuals showed a higher prevalence of hypertension than elderly individuals with normal weight, after controlling for age. In men, a lower RHGS was associated with a higher prevalence of hypertension after controlling for age (weak RHGS: 1.09 OR, 1.00–1.17 95% CI; middle RHGS: 1.21 OR, 1.12–1.31 95% CI vs. strong RHGS). [Conclusion]A higher BMI was associated with the prevalence of hypertension in the elderly Korean population. In addition, a lower RHGS was associated with the prevalence of hypertension in elderly Korean men.     

A polymorphism in the porcine miR‐208b is associated with microRNA biogenesis and expressions of SOX‐6 and MYH7 with effects on muscle fibre characteristics and meat quality

MicroRNAs (miRNAs) encoded by the myosin heavy chain (MHC) genes are muscle‐specific miRNAs (myomiRs) and regulate the expression of MHC isoforms in skeletal muscle. These miRNAs have been implicated in muscle fibre types and their characteristics by affecting the heterogeneity of myosin. In pigs, miR‐208b and miR‐499 are embedded in introns of MYH7 and MYH7b respectively. Here, we identified a novel single nucleotide polymorphism (SNP) in intron 30 of MYH7 by which porcine miR‐208b is encoded. Based on the association study using a total of 487 pigs including Berkshire (n = 164), Landrace (n = 121) and Yorkshire (n = 202), the miR‐208b SNP (g.17104G>A) had significant effects on the proportions of types I and IIb fibre numbers (P < 0.010) among muscle fibre characteristics and on drip loss (P = 0.012) in meat quality traits. Moreover, the SNP affected the processing of primary miR‐208b into precursor miR‐208b with a marginal trend towards significance (P = 0.053), thereby leading to significant changes in the levels of mature miR‐208b (P = 0.009). These SNP‐dependent changes in mature miR‐208b levels were negatively correlated with the expression levels of its target gene, SOX‐6 (P = 0.038), and positively associated with the expression levels of its host gene, MYH7 (P = 0.046). Taken together, our data suggest that the porcine miR‐208b SNP differentially represses the expression of SOX‐6 by regulating miRNA biogenesis, thereby affecting the expression of MYH7 and the traits of muscle fibre characteristics and meat quality.