A novel actinomycete derived from wheat heads degrades deoxynivalenol in the grain of wheat and barley affected by Fusarium head blight

Deoxynivalenol (DON) is a hazardous and globally prevalent mycotoxin in cereals. It commonly accumulates in the grain of wheat, barley and other small grain cereals affected by Fusarium head blight (caused by several Fusarium species). The concept of reducing DON in naturally contaminated grain of wheat or barley using a DON-degrading bacterium is promising but has not been accomplished. In this study, we isolated a novel DON-utilising actinomycete, Marmoricola sp. strain MIM116, from wheat heads through a novel isolation procedure including an in situ plant enrichment step. Strain MIM116 had background degradation activity, and the activity was enhanced twofold by the consumption of DON. Among Tween 20, Triton X-100 and Tween 80, we selected Tween 80 as a spreading agent of strain MIM116 because it promoted DON degradation and the growth of strain MIM116 in the presence of DON. The inoculation of MIM116 cell suspension plus 0.01% Tween 80 into 1,000 harvested kernels of wheat and barley resulted in a DON decrease from approximately 3 mg kg^?1 to less than 1 mg kg^?1 of dry kernels, even when cells had only basal levels of DON-degrading activity. To the best of our knowledge, this is the first report that describes (1) the isolation of a DON-degrading bacterium from wheat heads, (2) the effects of surfactants on the biodegradation of DON and (3) the decrease of DON levels in naturally contaminated wheat and barley grain using a DON-degrading bacterium.     

Defect of Mitotic Vimentin Phosphorylation Causes Microophthalmia and Cataract via Aneuploidy and Senescence in Lens Epithelial Cells

Vimentin, a type III intermediate filament (IF) protein, is phosphorylated predominantly in mitosis. The expression of a phosphorylation-compromised vimentin mutant in T24 cultured cells leads to cytokinetic failure, resulting in binucleation (multinucleation). The physiological significance of intermediate filament phosphorylation during mitosis for organogenesis and tissue homeostasis was uncertain. Here, we generated knock-in mice expressing vimentin that have had the serine sites phosphorylated during mitosis substituted by alanine residues. Homozygotic mice (VIM^SA/SA) presented with microophthalmia and cataracts in the lens, whereas heterozygotic mice (VIM^WT/SA) were indistinguishable from WT (VIM^WT/WT) mice. In VIM^SA/SA mice, lens epithelial cell number was not only reduced but the cells also exhibited chromosomal instability, including binucleation and aneuploidy. Electron microscopy revealed fiber membranes that were disorganized in the lenses of VIM^SA/SA, reminiscent of similar characteristic changes seen in age-related cataracts. Because the mRNA level of the senescence (aging)-related gene was significantly elevated in samples from VIM^SA/SA, the lens phenotype suggests a possible causal relationship between chromosomal instability and premature aging.     

Brain-derived Neurotrophic Factor (BDNF) Induces Sustained Intracellular Ca2+ Elevation through the Up-regulation of Surface Transient Receptor Potential 3 (TRPC3) Channels in Rodent Microglia

Microglia are immune cells that release factors, including proinflammatory cytokines, nitric oxide (NO), and neurotrophins, following activation after disturbance in the brain. Elevation of intracellular Ca²⁺ concentration ([Ca²⁺]_i) is important for microglial functions such as the release of cytokines and NO from activated microglia. There is increasing evidence suggesting that pathophysiology of neuropsychiatric disorders is related to the inflammatory responses mediated by microglia. Brain-derived neurotrophic factor (BDNF) is a neurotrophin well known for its roles in the activation of microglia as well as in pathophysiology and/or treatment of neuropsychiatric disorders. In this study, we sought to examine the underlying mechanism of BDNF-induced sustained increase in [Ca²⁺]_i in rodent microglial cells. We observed that canonical transient receptor potential 3 (TRPC3) channels contribute to the maintenance of BDNF-induced sustained intracellular Ca²⁺ elevation. Immunocytochemical technique and flow cytometry also revealed that BDNF rapidly up-regulated the surface expression of TRPC3 channels in rodent microglial cells. In addition, pretreatment with BDNF suppressed the production of NO induced by tumor necrosis factor α (TNFα), which was prevented by co-adiministration of a selective TRPC3 inhibitor. These suggest that BDNF induces sustained intracellular Ca²⁺ elevation through the up-regulation of surface TRPC3 channels and TRPC3 channels could be important for the BDNF-induced suppression of the NO production in activated microglia. We show that TRPC3 channels could also play important roles in microglial functions, which might be important for the regulation of inflammatory responses and may also be involved in the pathophysiology and/or the treatment of neuropsychiatric disorders.     

A 570-kb DNA Sequence of the Escherichia coli K-12 Genome Corresponding to the 28.0-40.1 min Region on the Linkage Map

The 569,750 base pair sequence corresponding to the 28.0–40.1min region on the genetic map of Escherichia coli K-12 (W3110)was determined. This region includes the replication terminusregion and contained at least 549 potential open reading frames.Among them, 160 (29%) were previously reported, 174 (32%) werehomologous to other known genes, 102 (18%) were identical orsimilar to hypothetical genes registered in databases, and theremaining 113 (21%) did not show a significant similarity toany other gene. Of interest was the finding of a large numberof genes and gene clusters in andnear the replication terminationregion which had been thought to be genetically silent. Thoseincludeda cluster of genes for fatty acid ß-oxidation,the third copy of the pot (spermidine/putrescine transport system)gene cluster, the second dpp (dipeptide transport system) operon,the second dsm (anaerobic dimethyl sulfoxide reductase) operon,a cluster of fim (fimbrial) genes anda DNA helicase-like genewith a high molecular weight. In addition, we found the dnaC-and dnaT-like genes in the cryptic prophage, Rac, anda numberof genes originated probably from plasmids.     

A Porphyromonas gingivalis Periplasmic Novel Exopeptidase,Acylpeptidyl Oligopeptidase,Releases N-Acylated Di- and Tripeptides from Oligopeptides

Exopeptidases, including dipeptidyl- and tripeptidylpeptidase, are crucial for the growth of Porphyromonas gingivalis, a periodontopathic asaccharolytic bacterium that incorporates amino acids mainly as di- and tripeptides. In this study, we identified a novel exopeptidase, designated acylpeptidyl oligopeptidase (AOP), composed of 759 amino acid residues with active Ser⁶¹⁵ and encoded by PGN_1349 in P. gingivalis ATCC 33277. AOP is currently listed as an unassigned S9 family peptidase or prolyl oligopeptidase. Recombinant AOP did not hydrolyze a Pro-Xaa bond. In addition, although sequence similarities to human and archaea-type acylaminoacyl peptidase sequences were observed, its enzymatic properties were apparently distinct from those, because AOP scarcely released an N-acyl-amino acid as compared with di- and tripeptides, especially with N-terminal modification. The k_cat/K_m value against benzyloxycarbonyl-Val-Lys-Met-4-methycoumaryl-7-amide, the most potent substrate, was 123.3 ± 17.3 μm⁻¹ s⁻¹, optimal pH was 7–8.5, and the activity was decreased with increased NaCl concentrations. AOP existed predominantly in the periplasmic fraction as a monomer, whereas equilibrium between monomers and oligomers was observed with a recombinant molecule, suggesting a tendency of oligomerization mediated by the N-terminal region (Met¹⁶–Glu¹⁰¹). Three-dimensional modeling revealed the three domain structures (residues Met¹⁶–Ala¹²⁶, which has no similar homologue with known structure; residues Leu¹²⁷–Met⁴⁹⁵ (β-propeller domain); and residues Ala⁴⁹⁶–Phe⁷³⁶ (α/β-hydrolase domain)) and further indicated the hydrophobic S1 site of AOP in accord with its hydrophobic P1 preference. AOP orthologues are widely distributed in bacteria, archaea, and eukaryotes, suggesting its importance for processing of nutritional and/or bioactive oligopeptides.     

Variations in the activity of fatty ACYL-CoA desaturases and electron-transport components in Tetrahymena microsomes with temperature and age of culture

1. 1.|Alterations in the fatty acid composition of microsomes were most marked in the exponential phase of both 39.5- or 15°C- grown Tetrahymena pyriformis NT-1.

2. 2.|Activities of palmitoyl-CoA and stearoyl-CoA desaturases were lower in 15°C cells than in 39.5°C cells, while the activity of oleoyl-CoA desaturase was higher in 15°C cells.

3. 3.|Activities of the terminal component of the desaturation system as well as all three desaturases (palmitoyl-CoA, stearoyl-CoA, oleoyl-CoA) were higher in the exponential phase than in the stationary phase for cells grown at both temperatures.

4. 4.|NAD(P)H-cytochrome c reductase activity and cytochrome b₅ content were reduced whereas NADH-ferricyanide reductase activity was increased in the stationary phase at both 39.5 and 15°C.

Relation of proliferative activity to survival in patients with advanced gastric cancer

The proliferative activities of 98 biopsied specimens of advanced gastric cancers were measured by the in vitro bromodeoxyuridine (BrdU) labelling method. BrdU labelling indices (LIs) varied from 4.8 to 45.1%. There was no correlation of BrdU LIs and histological type, distant metastasis, serosal invasion, macroscopic type or tumor size. However, BrdU LIs of tumors with lymph node metastases were significantly higher than those without them. Patients with tumors showing high BrdU LIs had a three-fold relative risk of death, as compared with those showing low BrdU LIs. When the BRdU LIs and all the clinicopathological parameters were entered simultaneously into the Cox model, BrdU LIs, peritoneal dissemination and serosal invasion emerged as independent prognostic parameters. These results indicate that the in vitro BrdU labelling method using biopsied materials may be useful in predicting lymph node metastasis preoperatively and designing operative procedures for individual patients.