Yeast Cell Wall Extract Induces Disease Resistance against Bacterial and Fungal Pathogens in Arabidopsis thaliana and Brassica Crop

Housaku Monogatari (HM) is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA) pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.     

RAD18 Activates the G2/M Checkpoint through DNA Damage Signaling to Maintain Genome Integrity after Ionizing Radiation Exposure

The ubiquitin ligase RAD18 is involved in post replication repair pathways via its recruitment to stalled replication forks, and its role in the ubiquitylation of proliferating cell nuclear antigen (PCNA). Recently, it has been reported that RAD18 is also recruited to DNA double strand break (DSB) sites, where it plays novel functions in the DNA damage response induced by ionizing radiation (IR). This new role is independent of PCNA ubiquitylation, but little is known about how RAD18 functions after IR exposure. Here, we describe a role for RAD18 in the IR-induced DNA damage signaling pathway at G2/M phase in the cell cycle. Depleting cells of RAD18 reduced the recruitment of the DNA damage signaling factors ATM, γH2AX, and 53BP1 to foci in cells at the G2/M phase after IR exposure, and attenuated activation of the G2/M checkpoint. Furthermore, depletion of RAD18 increased micronuclei formation and cell death following IR exposure, both in vitro and in vivo. Our data suggest that RAD18 can function as a mediator for DNA damage response signals to activate the G2/M checkpoint in order to maintain genome integrity and cell survival after IR exposure.     

Helical image reconstruction of the outward-open human erythrocyte band 3 membrane domain in tubular crystals

The C-terminal membrane domain of erythrocyte band 3 functions as an anion exchanger. Here, we report the three-dimensional (3D) structure of the membrane domain in an inhibitor-stabilized, outward-open conformation at 18 Å resolution. Unstained, frozen-hydrated tubular crystals containing the membrane domain of band 3 purified from human red blood cells (hB3MD) were examined using cryo-electron microscopy and iterative helical real-space reconstruction (IHRSR). The 3D image reconstruction of the tubular crystals showed the molecular packing of hB3MD dimers with dimensions of 60 × 110 Å in the membrane plane and a thickness of 70 Å across the membrane. Immunoelectron microscopy and carboxyl-terminal digestion demonstrated that the intracellular surface of hB3MD was exposed on the outer surface of the tubular crystal. A 3D density map revealed that hB3MD consists of at least two subdomains and that the outward-open form is characterized by a large hollow area on the extracellular surface and continuous density on the intracellular surface.     

Reduced expression of INK4a/ARF genes in stem-like sphere cells from rat sarcomas

The presence of cancer stem cells, in both hematopoietic and solid malignancies, has been recently linked to their pathogenesis. We aimed to identify the characteristics and stem-like properties of sphere-colony forming cells in rat osteosarcoma and malignant fibrous histiocytoma cell lines. The results showed that both cell lines possessed an ability to form spherical, clonally expanding colonies in anchorage-independent, serum-starved conditions in N2/1% methylcellulose medium. The sphere cells showed stem-like properties with the ability to self-renew, and expressed the stem cell-related STAT3 and Bmi1 genes. Interestingly, spheres from both sarcomas remarkably decreased the expression of INK4a/ARF locus genes, p16(INK4a) and p19(ARF), which could be related to the resistance against cell senescence and apoptosis. Spheres showed strong tumorigenicity with metastatic potential in vivo via the inoculation into syngeneic rats, suggesting the presence of these populations might contribute to the tumor development such as metastasis via the resistance to apoptotic stimuli.     

Identification of critical structural determinants responsible for octopamine binding to the alpha-adrenergic-like Bombyx mori octopamine receptor

Octopamine (OA) is a biogenic amine with a widespread distribution in the insect nervous system. OA modulates and/or regulates various behavioral patterns of insects as a neurotransmitter, neuromodulator, and neurohormone. OA receptors (OARs) belong to one of the families of G protein-coupled receptors (GPCRs). The binding of OA to OARs is coupled to the activation of the specific G proteins, which induces the release of intracellular second messengers such as cAMP and/or calcium. We previously reported the isolation of an OAR (BmOAR1) from Bombyx mori. In the study presented here, five mutated BmOAR1s were constructed with a point mutation in the putative binding crevice and expressed in HEK-293 cells. The S202A mutant receptor was found to retain the cAMP response to OA as does the wild-type receptor, but such function was impaired in the other four mutants (D103A, S198A, Y412F, and S198A/S202A). Furthermore, competition binding assays using [3H]OA and calcium mobilization assays gave results that were approximately consistent with those of the cAMP assays. Taken together, the results indicate that D103 and S198 are involved in the binding and activation of BmOAR1 with OA through electrostatic or hydrogen bond interactions, but S202 does not appear to participate in this process. Y412 seems to be involved in one of the active forms of BmOAR1. These findings should prove helpful in designing new pest control chemicals.     

Structural factors contributing to the Abl/Lyn dual inhibitory activity of 3-substituted benzamide derivatives

To investigate why 3-substituted benzamide derivatives show dual inhibition of Abl and Lyn protein tyrosine kinases, we determined their inhibitory activities against Abl and Lyn, carried out molecular modeling, and conducted a structure-activity relationship study with the aid of a newly determined X-ray structure of the Abl/Lyn dual inhibitor INNO-406 (formerly known as NS-187) bound to human Abl. We found that this series of compounds interacted with both kinases in very similar ways, so that they can inhibit both kinases effectively.     

Tryptophan auxotroph mutants suppress the superroot2 phenotypes,modulating IAA biosynthesis in arabidopsis

Plant phytohormone, Indole-3-acetic acid (IAA ), is synthesized by tryptophan (trp) dependent and independent pathway. Here we report that tryptophan auxotroph mutants completely suppressed the abnormalities of auxin over production mutant, superroot2. SUR2 is considered to modulate Trp dependent pathway, resulting IAA accumulation in Arabidopsis. Tryptophan auxotroph mutants showed hyper-sensitivity to the auxin polar transport inhibitor, NPA, on the phenotype of reduced gravitropism. These results together with the results of histochemical analyses, tryptophan auxotroph mutants seem to have a complete defect in Trp dependent IAA biosynthesis pathway, and it is also suggested that the Trp dependent pathway is responsible for the normal root gravitropism.Key words: Auxin, Trp dependent pathway, trp mutants, sur2, arabidopsis     

Relationship of number of remaining teeth to health-related quality of life in community-dwelling elderly

Objective: The aim of this study was to evaluate the relationship between number of remaining teeth and health‐related quality of life in community‐dwelling elderly. Subjects: A total of 207 participants who were community‐dwelling, 85 years of age. Data were from a population‐based study of age‐related general and oral health in Fukuoka Prefecture, Japan. Measurements: The Japanese version of the Short Form 36 Health Survey (SF‐36). Results: The mental component score for the participants, from the SF‐36, was higher than the Japanese national norm for those aged ≥70 years. There were no significant differences in the mean of any scores on the SF‐36 by having spouse, living with family, or education level. The mean of the SF‐36 scores of physical functioning (PF) and of the physical component scores were significantly higher in the 85‐year‐old participants with ≥20 teeth than in those with ≤19 teeth (p < 0.05 and p < 0.01 respectively). In addition, a significant difference (p < 0.05) was observed between the mean of participants with ≥20 teeth and those with ≤19 teeth after adjustment for region where the participant lived, activities of daily living (ADL), and sex. The PF (p < 0.001), role‐physical (p < 0.005), bodily pain (p < 0.001), vitality (p < 0.001), social functioning (p < 0.05), and physical component (p < 0.001) scores were significantly higher in participants with a good activities of daily living (ADL) assessment. However, ADL was not associated with the number of teeth. Conclusions: The findings of the present study indicated that 85‐year‐old participants with ≥20 teeth had better subjective physical health than those with ≤19 teeth.