Inactivation of Bacillus spores by the combination of moderate heat and low hydrostatic pressure in ketchup and potage

The combination effect of moderate heat and low hydrostatic pressure (MHP) on the reduction of Bacillus subtilis, Bacillus coagulans and Geobacillus stearothermophilus spores in food materials (potage and ketchup) was investigated. These bacterial spores were suspended in potage (pH 7), acidified potage (pH 4), neutralized ketchup (pH 7) and ketchup (pH 4). The suspensions were treated with and without pressure (100 MPa) and temperatures of 65-85 degrees C for 3 to 12 h. The bacterial spores were inactivated by 4-8 log cycles during MHP treatment in potage, acidified potage and ketchup, whereas the spores were highly resistant to long time heat treatment in potage and neutralized ketchup. The degrees of spore destruction were mostly dependent on pH and medium composition during MHP treatment. The inactivation effect in MHP treatment was higher at the pH 7 than at pH 4 both in ketchup and potage. The bacterial spores showed higher inactivation in potage than ketchup during MHP treatment.     

Hetero-stereocomplex formation of stereoblock copolymer of substituted and non-substituted poly(lactide)s

The crystallization behavior of the stereoblock copolymer of substituted and non-substituted poly(lactide)s, i.e., poly(d-2-hydroxybutyrate) and poly(l-lactide) chains having the opposite configurations [P(D-2HB)-b-PLLA] and the reference block copolymer of poly(d-2-hydroxybutyrate) and poly(d-lactide) chains with the identical configurations [P(D-2HB)-b-PDLA] was investigated. At the crystallizable temperature range of 60-160 °C, the crystallized P(D-2HB)-b-PLLA contained solely the hetero-stereocomplex crystallites as a crystalline species, without formation of poly(d-2-hydroxybutyrate) or poly(l-lactide) homo-crystallites, in contrast with their polymer blends. On the other hand, at the crystallizable temperature range of 60-140 °C, the crystallized P(D-2HB)-b-PDLA had only PDLA homo-crystallites as crystalline species, reflecting no co-crystallites formation between poly(d-2-hydroxybutyrate) and poly(d-lactide) chains having the same configurations. The equilibrium melting temperature of hetero-stereocomplex crystallites in P(D-2HB)-b-PLLA was 189.0 °C, which was higher than 171.3 °C of PDLA homo-crystallites in P(D-2HB)-b-PDLA. Although the final crystallinity of P(D-2HB)-b-PLLA was higher than those of P(D-2HB)-b-PDLA, the spherulite growth rate of P(D-2HB)-b-PLLA was lower.The regime analysis indicated unusual nucleation mechanism of P(D-2HB)-b-PLLA.     

Impact of Oncogenic Targets by Tumor-Suppressive miR-139-5p and miR-139-3p Regulation in Head and Neck Squamous Cell Carcinoma

We newly generated an RNA-sequencing-based microRNA (miRNA) expression signature of head and neck squamous cell carcinoma (HNSCC). Analysis of the signature revealed that both strands of some miRNAs, including miR-139-5p (the guide strand) and miR-139-3p (the passenger strand) of miR-139, were downregulated in HNSCC tissues. Analysis of The Cancer Genome Atlas confirmed the low expression levels of miR-139 in HNSCC. Ectopic expression of these miRNAs attenuated the characteristics of cancer cell aggressiveness (e.g., cell proliferation, migration, and invasion). Our in silico analyses revealed a total of 28 putative targets regulated by pre-miR-139 (miR-139-5p and miR-139-3p) in HNSCC cells. Of these, the GNA12 (guanine nucleotide-binding protein subunit alpha-12) and OLR1 (oxidized low-density lipoprotein receptor 1) expression levels were identified as independent factors that predicted patient survival according to multivariate Cox regression analyses (p = 0.0018 and p = 0.0104, respectively). Direct regulation of GNA12 and OLR1 by miR-139-3p in HNSCC cells was confirmed through luciferase reporter assays. Moreover, overexpression of GNA12 and OLR1 was detected in clinical specimens of HNSCC through immunostaining. The involvement of miR-139-3p (the passenger strand) in the oncogenesis of HNSCC is a new concept in cancer biology. Our miRNA-based strategy will increase knowledge on the molecular pathogenesis of HNSCC.     

Beta-1,3 Oligoglucans Specifically Bind to Immune Receptor CD28 and May Enhance T Cell Activation

Beta glucans are known to have immunomodulatory effects that mediated by a variety of mechanisms. In this article, we describe experiments and simulations suggesting that beta-1,3 glucans may promote activation of T cells by a previously unknown mechanism. First, we find that treatment of a T lymphoblast cell line with beta-1,3 oligoglucan significantly increases mRNA levels of T cell activation-associated cytokines, especially in the presence of the agonistic anti-CD3 antibody. This immunostimulatory activity was observed in the absence of dectin-1, a known receptor for beta-1,3 glucans. To clarify the molecular mechanism underlying this activity, we performed a series of molecular dynamics simulations and free-energy calculations to explore the interaction of beta-1,3 oligoglucans with potential immune receptors. While the simulations reveal little association between beta-1,3 oligoglucan and the immune receptor CD3, we find that beta-1,3 oligoglucans bind to CD28 near the region identified as the binding site for its natural ligands CD80 and CD86. Using a rigorous absolute binding free-energy technique, we calculate a dissociation constant in the low millimolar range for binding of 8-mer beta-1,3 oligoglucan to this site on CD28. The simulations show this binding to be specific, as no such association is computed for alpha-1,4 oligoglucan. This study suggests that beta-1,3 glucans bind to CD28 and may stimulate T cell activation collaboratively with T cell receptor activation, thereby stimulating immune function.     

Biosynthesis and characterization of novel polyhydroxyalkanoate copolymers consisting of 3-hydroxy-2-methylbutyrate and 3-hydroxyhexanoate

In this study, in order to explore the possibility of biosynthesizing a novel polyhydroxyalkanoate (PHA), copolymerization of 3-hydroxy-2-methylbutyrate (3H2MB) as the α-position methylated monomer and 3-hydroxyhexanoate (3HHx) as the medium-chain-length monomer was performed to obtain P(3H2MB-co-3HHx). The β-oxidation-deficient Escherichia coli LSBJ, harboring the PHA biosynthetic operon from Aeromonas caviae and the propionyl-CoA transferase gene (pct) from Megasphaera elsdenii, was cultured with feeding tiglic and hexanoic acids as the precursors for 3H2MB and 3HHx, respectively. It was observed that pct expression was highly effective to enhance the incorporation of 3H2MB into PHA. The biosynthesized PHA was composed of 3H2MB and 3HHx units only, and the 3H2MB fraction varied in the range of 36–60 mol% depending on the culture conditions. These PHAs exhibited glass transition temperatures between ?11 to ?17 °C; moreover, no melting peak was observed during analysis using differential scanning calorimetry. This study demonstrated the biosynthesis of a hitherto unreported PHA by engineering metabolic pathway in E. coli.     

Semi-interpenetrating polymer networks composed of poly(l-lactide) and diisocyanate-bridged 4-arm star-shaped ɛ-caprolactone oligomers

Semi-interpenetrating polymer networks (semi-IPNs) were prepared by reactions of methylenediphenyl 4,4’-diisocyanate (MDI) and hydroxy-terminated 4-arm star-shaped ε-caprolactone oligomers (H4CLO_n's) with the degrees of polymerization per one arm, n = 3, 5 and 10 in the presence of poly(l-lactide) (PLA). Morphologies, thermal and mechanical properties of the MDI-bridged H4CLO_n (MH4CLO_n)/PLA semi-IPNs were evaluated by comparing with those of poly(?-caprolactone) (PCL)/PLA blends. Two tan δ peaks related to MH4CLO_n and PLA were observed in a dynamic mechanical curve of the semi-IPN. Although all the semi-IPNs and blends had micro-phase separated morphologies, the phase-separated droplets of MH4CLO₅/PLA 50/50 were much finer than those of PCL/PLA 50/50. Differential scanning calorimetry (DSC) analyses revealed that MH4CLO₃ and MH4CLO₅ are substantially amorphous, while MH4CLO₁₀ is semi-crystalline, and that cold crystallization of the PLA component of MH4CLO_n/PLA is more strongly disturbed for the semi-IPN with a smaller n value and more MH4CLO_n content. Tensile modulus, toughness and elongation at break of MH4CLO₅/PLA 50/50 semi-IPN were much higher than those of PCL/PLA 50/50 blend.     

Investigation of wall stress development and packing ratio distribution in the metal hydride reactor

The strains generated in a reaction vessel of hydrogen storage alloys and the packing ratio distribution inside the vessel were measured in order to analyze the effects of packing on stress. More specifically strains generated on the vessel’s surface were measured when hydrogen is repeatedly absorbed and desorbed by the packed bed in the reaction vessel. The amount of deformation, local packing ratios and relative particle volumes in the vessel were also measured after repeated hydrogen absorption–desorption. As absorption–desorption was performed repeatedly, agglomeration regions where the value of the local packing ratio was around 0.6 were formed, and particularly strong stress was generated in these regions, causing deformation. More hydrogen packing causes agglomeration regions to form over a wider area. Since alloys are pulverized by repeated absorption–desorption, and concentrate in the lower parts of the vessel, agglomeration regions are also formed in the lower parts. Our experiments also revealed that the resulting agglomeration regions have a packing ratio of about 0.6.