Genetic diversity of Lactobacillus delbrueckii isolated from raw milk in Hokkaido, Japan

Lactic acid bacteria (LAB) play important roles in acid production and flavor formation in fermented dairy products. Lactic acid bacteria strains with distinct characteristics confer unique features to products. Diverse LAB have been identified in raw milk and traditional fermented milk prepared from raw milk. However, little is known about LAB in raw milk in Japan. To preserve diverse LAB as potential starters or probiotics for future use, we have isolated and identified various kinds of LAB from raw milk produced in Japan. In this study, we focused on Lactobacillus delbrueckii, one of the most important species in the dairy industry. We identified L. delbrueckii subspecies isolated from raw milk in Hokkaido, Japan, by analyzing intraspecific diversity using 4 distinct methods, hsp60 cluster analysis, multilocus sequence analysis, core-genome analysis, and whole-genome analysis based on average nucleotide identity. The subspecies distribution and a new dominant subset of L. delbrueckii from raw milk in Japan were revealed. The discovery of new strains with different genotypes is important for understanding the geographic distribution and characteristics of the bacteria and further their use as a microbial resource with the potential to express unconventional flavors and functionalities. The strains identified in this study may have practical applications in the development of fermented dairy products.

Aerial Manipulator Control Method Based on Generalized Jacobian

This paper describes a control method for an aerial manipulator on an unmanned aerial vehicle (UAV) by using a generalized Jacobian (GJ). Our task is to realize visual check of bridge inspection by employing a UAV with a multi-degree-of-freedom (DoF) manipulator on its top. The manipulator is controlled by using the GJ. Subsequently, by comparing the aerial manipulator control with a conventional Jacobian experimentally, we discovered that the accuracy of the control improved by applying the GJ. The manipulator has three DoFs in the X-Z plane of the UAV coordinate system. The experiment shows that the manipulator controlled with the GJ can compensate for the pose error of the body by 54.5% and 47.7% in the X- and Z-axes, respectively.

Magnetic self-assembly of toroidal hepatic microstructures for micro-tissue fabrication

In this study, we developed a procedure for assembling hepatic microstructures into tube shapes using magnetic self-assembly for in vitro 3D micro-tissue fabrication. To this end, biocompatible hydrogels, which have a toroidal shape, were made using the micro-patterned electrodeposition method. Ferrite particles were used to coat the fabricated toroidal hydrogel microcapsules using a poly-L-lysine membrane. The microcapsules were then magnetized with a 3 T magnetic field, and assembled using a magnetic self-assembly process. During electrodeposition, hepatic cells were trapped inside the microcapsules, and they were cultured to construct tissue-like structures. The magnetized toroidal microstructures then automatically assembled to form tube structures. Shaking was used to enhance the assembly process, and the shaking speed was experimentally optimized to achieve the high-speed assembly of longer tube structures. The flow velocity inside the dish during shaking was measured by particle image velocimetry. Hepatic functions were evaluated to check for side-effects of the magnetized ferrite particles on the microstructures. Collectively, our findings indicated that the developed method can achieve the high-speed assembly of a large number of microstructures to form tissue-like hepatic structures.

Evaluation of genotoxicity and subchronic toxicity of standardized rose hip extract

Rose hip is the fruit of the rose plant, which is widely used in food, cosmetics and as a traditional medicine. Therefore, rose hip is considered safe and has a sufficient history of consumption as food. However, few studies have reported on the safety of rose hip extracts in toxicological analyses. Thus, to evaluate the safety of rosehip polyphenol MJ (RHPMJ), an aqueous ethanol extract standardized with the trans-tiliroside content, we performed genotoxicity and 90-day repeated oral dose toxicity studies in compliance with the Organisation for Economic Co-operation and Development-Good Laboratory Practice. RHPMJ did not induce gene mutations in reverse mutation tests of Salmonella typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2 uvrA strains and did not induce chromosomal aberrations in cultured Chinese hamster lung (CHL/IU) cells. Moreover, micronucleus tests using rat bone marrow showed RHPMJ had no micronucleus-inducing potential. Finally, 90-day repeated oral dose toxicity studies (100–1000 mg/kg) in male and female rats showed no treatment-related toxicity in rats. These data indicate that the RHPMJ had no genotoxicity and a no-observed-adverse-effect level greater than 1000 mg/kg in rats.

A novel single virus infection system reveals that influenza virus preferentially infects cells in g1 phase

BACKGROUND

Influenza virus attaches to sialic acid residues on the surface of host cells via the hemagglutinin (HA), a glycoprotein expressed on the viral envelope, and enters into the cytoplasm by receptor-mediated endocytosis. The viral genome is released and transported in to the nucleus, where transcription and replication take place. However, cellular factors affecting the influenza virus infection such as the cell cycle remain uncharacterized.

METHODS/RESULTS

To resolve the influence of cell cycle on influenza virus infection, we performed a single-virus infection analysis using optical tweezers. Using this newly developed single-virus infection system, the fluorescence-labeled influenza virus was trapped on a microchip using a laser (1064 nm) at 0.6 W, transported, and released onto individual H292 human lung epithelial cells. Interestingly, the influenza virus attached selectively to cells in the G1-phase. To clarify the molecular differences between cells in G1- and S/G2/M-phase, we performed several physical and chemical assays. Results indicated that: 1) the membranes of cells in G1-phase contained greater amounts of sialic acids (glycoproteins) than the membranes of cells in S/G2/M-phase; 2) the membrane stiffness of cells in S/G2/M-phase is more rigid than those in G1-phase by measurement using optical tweezers; and 3) S/G2/M-phase cells contained higher content of Gb3, Gb4 and GlcCer than G1-phase cells by an assay for lipid composition.

CONCLUSIONS

A novel single-virus infection system was developed to characterize the difference in influenza virus susceptibility between G1- and S/G2/M-phase cells. Differences in virus binding specificity were associated with alterations in the lipid composition, sialic acid content, and membrane stiffness. This single-virus infection system will be useful for studying the infection mechanisms of other viruses.

The lipid mediator protectin D1 inhibits influenza virus replication and improves severe influenza

Influenza A viruses are a major cause of mortality. Given the potential for future lethal pandemics, effective drugs are needed for the treatment of severe influenza such as that caused by H5N1 viruses. Using mediator lipidomics and bioactive lipid screen, we report that the omega-3 polyunsaturated fatty acid (PUFA)-derived lipid mediator protectin D1 (PD1) markedly attenuated influenza virus replication via RNA export machinery. Production of PD1 was suppressed during severe influenza and PD1 levels inversely correlated with the pathogenicity of H5N1 viruses. Suppression of PD1 was genetically mapped to 12/15-lipoxygenase activity. Importantly, PD1 treatment improved the survival and pathology of severe influenza in mice, even under conditions where known antiviral drugs fail to protect from death. These results identify the endogenous lipid mediator PD1 as an innate suppressor of influenza virus replication that protects against lethal influenza virus infection.

CXCL10-CXCR3 enhances the development of neutrophil-mediated fulminant lung injury of viral and nonviral origin

RATIONALE

Patients who developed acute respiratory distress syndrome (ARDS) after infection with severe respiratory viruses (e.g., severe acute respiratory syndrome-coronavirus, H5N1 avian influenza virus), exhibited unusually high levels of CXCL10, which belongs to the non-ELR (glutamic-leucine-arginine) CXC chemokine superfamily. CXCL10 may not be a bystander to the severe virus infection but may directly contribute to the pathogenesis of neutrophil-mediated, excessive pulmonary inflammation.

OBJECTIVES

We investigated the contribution of CXCL10 and its receptor CXCR3 axis to the pathogenesis of ARDS with nonviral and viral origins.

METHODS

We induced nonviral ARDS by acid aspiration and viral ARDS by intratracheal influenza virus infection in wild-type mice and mice deficient in CXCL10, CXCR3, IFNAR1 (IFN-α/β receptor 1), or TIR domain-containing adaptor inducing IFN-β (TRIF).

MEASUREMENTS AND MAIN RESULTS

We found that the mice lacking CXCL10 or CXCR3 demonstrated improved severity and survival of nonviral and viral ARDS, whereas mice that lack IFNAR1 did not control the severity of ARDS in vivo. The increased levels of CXCL10 in lungs with ARDS originate to a large extent from infiltrated pulmonary neutrophils, which express a unique CXCR3 receptor via TRIF. CXCL10-CXCR3 acts in an autocrine fashion on the oxidative burst and chemotaxis in the inflamed neutrophils, leading to fulminant pulmonary inflammation.

CONCLUSIONS

CXCL10-CXCR3 signaling appears to be a critical factor for the exacerbation of the pathology of ARDS. Thus, the CXCL10-CXCR3 axis could represent a prime therapeutic target in the treatment of the acute phase of ARDS of nonviral and viral origins.

In vitro immunization of human peripheral blood lymphocytes: establishment of B cell lines secreting IgM specific for cholera toxin B subunit from lymphocytes stimulated with IL-2 and IL-4

In vitro immunization (IVI) techniques have a great potential in the production of human monoclonal antibodies (MAbs) against various antigens. An IVI method of human peripheral blood lymphocytes (PBL) has been developed with a human lung adenocarcinoma cell line in our laboratory. Although several cancer specific human MAbs were successfully generated by using this IVI method, it was not available for soluble antigens, which prompted us to improve the method for generation of human MAbs against soluble antigens. IVI with soluble antigens was effectively caused by the addition of muramyl dipeptides, interleukin-2 and interleukin-4. It was found that the difference of sensitivity of lymphocytes depending upon donors could be overcome by finding the optimal concentrations of IL-2 and IL-4. IVI of human PBL was performed with cholera toxin B subunit (CTB) and the immunized B cells were transformed by Epstein-Barr virus. Anti-CTB antibody was detected using an indirect ELISA. B cells producing anti-CTB antibodies were directly cloned by a soft agar cloning method.

Diversity of nematomorph and cohabiting nematode parasites in riparian ecosystems around the Kii Peninsula, Japan

Nematomorph parasites manipulate terrestrial invertebrate hosts to seek out and enter streams, thereby deriving substantial energy subsidies to stream salmonids. Despite this potential ecological role of nematomorphs, knowledge of their diversity remains unclear. Using molecular (i.e., 18S rRNA and mitochondrial COI genes) and morphological approaches, we explored the species diversity of suspected nematomorph specimens, as well as their terrestrial orthopteran hosts, in 10 stream and riparian ecosystems around the Kii Peninsula, central Honshu, Japan. We distinguished seven species of nematomorphs belonging to three genera based on molecular and morphological data. The identifications by the two approaches were consistent with each other at the genus level but partly not at the species level. Furthermore, among the suspected nematomorph specimens, eight nematode species belonging to the orders Mermithida and Trichocephalida were found from two sites. Several orthopterans, mainly camel crickets, were infected by nematomorphs and by a nematode without obvious species specificity. These results suggest that diverse parasites and their orthopteran hosts drive the parasite-mediated energy flow across the stream and riparian ecosystems.

Molecular analysis of cross-reactive human monoclonal antibody AE6F4 generated by in vitro immunization: Epitope mapping of AE6F4 antibody on 14-3-3 family proteins and cytokeratin 8

We reported previously that adenocarcinoma-reactive human monoclonal antibody AE6F4, which had been generated by in vitro immunization method, recognizes both 14-3-3protein and cytokeratin 8 (CK8). In this study, to analyze the cross-reactivity of AE6F4 antibody, epitopes of AE6F4 antibody on 14-3-3 proteins and CK8 were studied by using synthetic linear peptide scanning technology. To determine the locations of B cell epitope, 48 and 95 of decapeptides covering the entire 14-3-3 proteins and CK8, respectively,were synthesized and binding to AE6F4 antibody was examined by ELISA. The AE6F4 antibody was strongly reactive to peptides containing amino acid sequences TLWTSDTQGD in 14-3-3 proteins and INFLRQLYEE in CK8. These results indicate that AE6F4 antibody can recognize the different peptide sequences in 14-3-3 proteins and CK8.

Epitope analysis of human monoclonal antibody specific for rice allergenic protein generated by in vitro immunization

We previously established an in vitro immunization protocol for generating antigen specific human monoclonal antibodies (mAbs). In vitro immunization was performed against the soluble protein of rice allergenic protein (RA), resulting in the generation of three B cell clones, AC7-1/F9, CB7-1/E2 and CB7-8/F5, all of which produce a RA-specific human monoclonal IgM antibody. We attempted to map the epitope regions recognized by thesem Abs to characterize their specificities. We performed two rounds of epitope mapping, rough mapping using 10-mer peptides covering the full-length RA with 5 amino acids overlapping, and fine mapping using 8-mer peptides covering the putative epitope regions from the rough mapping with 1amino acid overlapping. As a result of the fine mapping,we identified the epitope regions of these three mAbs as(45)QVWQDCCRQ(54)L, (56)AVDDGWCRCGA(67)L and(91)FPGCRRG(98)D on the RA molecule and found to be identical. Furthermore, we determined the putative core epitope regions, which are critical for mAb binding to each region, (47)WQDCC(52)R and (60)GWC(63)R. The information about the epitope region on the RA molecule,which might trigger the allergenic response, would be useful to establish a specific immunotherapy against rice allergy.

Induction of basophilic and eosinophilic differentiation in the human leukemic cell line KU812

We have demonstrated that an immature prebasophilic cell line,KU812 cells can be induced to differentiate into basophil-like cells when cultured with hydrocortisone (HC) with enhanced cell surface expression of FcepsilonRI, a high affinity IgE receptor. In this study, we report that sodium nitroprusside (SNP), an intracellular NO donor, also induces cell surface expression of FcepsilonRI on KU812 cells. Cell surface FcepsilonRI expression was detected in about 20% of KU812 cells treated with SNP for 14 days as well as the cells treated with HC for 7 days, while non-treated KU812 cells did not express FcepsilonRI on their cell surface. However, Wright-Giemsa staining and flowcytometry analysis of CD13 and CD15 antigens on HC and SNP treated KU812 cells demonstrated that SNP induced eosinophilic differentiation in KU812 cells differently from HC which induced basophilic differentiation. To further confirm this result, we performed RT-PCR against mRNAs specific for eosinophils, such as eosinophil-derived neurotoxin (EDN) and eosinophil peroxidase(EPO). SNP treated KU812 cells but not HC treated cells expressed EDN and EPO mRNA depending upon the induction of differentiation,clearly demonstrating that SNP induces eosinophilic differentiation in KU812 cells. To clarify that different signaling cascades were activated in HC and SNP treated KU812 cells, we analyzed activities of AP-1, NF-AT and NF-kappaB transcription factors by EMSA, which are known to be involved in signal transduction pathways downstream from the FcepsilonRI molecule of basophils. All these three transcription factors were activated in HC treated KU812 cells,but not in non-treated and SNP treated KU812 cells. These results indicate that KU812 cells are multi-potent precursor cells which can be induced to differentiate into basophils and eosinophils upon exogenous signals, and that NO is an important factor to decide the eosinophilic differentiation in KU812 cells with enhanced surface expression of FcepsilonRI, and further suggest that different signaling cascades can be activated between basophilic and eosinophilic differentiation in KU812 cells.

Automatic Cell Cutting by High-Precision Microfluidic Control

We have developed automated cell cutting by highprecision microfluidic control using a high-response and high-precision syringe pump. A microfluidic chip containing 2 orthogonal microchannels was used for cutting animal cells softened by cytochalasin and aspirated and fixed in 1 microchannel, then a high-velocity microchannel flow was generated from another channel to cut the cell. To control microchannel flow precisely, we made a syringe pump with a minimum flow of 0.35 × 10-3µl/min and response time of 10 ms. The syringe pump was connected to the microfluidic chip by a thin, hard Teflon tube to reduce the pressure transmission delay between the syringe pump and microfluidic channel. A microbead control experiment depending on PI control using the syringe pump was conducted to check the microchannel flow delay. Bovine oocytes softened by cytochalasin were injected into the microfluidic chip and bisected by microscopic image volume measurement. This paper reports the automatic cell cutting strategy and system, a result of microbead positioning control, and a result of automatic cell cutting.

Design and Fabrication of All-in-One Unified Microfluidic Chip for Automation of Embryonic Cell Manipulation

We developed a microfluidic chip for automation of cloning process based on a new protocol. The protocol is based on removal of the zona pellucida outside the chip which contributes to simplify on-chip automation of cloning. Then, the oocytes are put into the chip. The design concept of the chip is summarized as follows. (1) The oocyte is cut into two parts. (2) The divided half oocyte is sorted with and without nucleus. (3) The half oocyte without nucleus is coupled with a donor cell, and (4) they are fused by an electrical field. For the current study, the all-in-one unified microfluidic chip was designed to execute (1) cutting, (2) sorting, and (3) coupling parts continuously for this process. Basic functions of these parts as well as fusion part are verified independently. Then, all-in-one unified microfluidic chip was successfully designed and fabricated.

Establishment of hybridomas producing cancer specific human antibodies from B cell line derived from PBL of a patient with adult T cell leukemia

Adult T cell leukemia (ATL) is a malignant disease characterized by tumorous proliferation of CD4(+) T cells infected with retrovirus human T cell leukemia virus Type-I (HTLV-I) and concurs with an autoimmune disease and cancer due to attenuated immune response. In this study, we established ATL patient derived B-cell line TM-1 producing cancer-specific IgM antibodies, and further characterized its antigen specificity by establishing hybridomas fused with human-mouse origin hetero-myeloma cell line RF-S1. We established three hybridoma cell lines termed 2E12, 3E9, and 3E10, which continuously secreted human IgM antibodies. Immunohistochemical staining of formalin-fixed tissue section using antibodies secreted from these hybridomas showed that these antibodies specifically recognized tumor sites of human colon adenocarcinomas. Antibody produced from hybridoma 3E9 bound to some of leukemic cell lines, but not to normal human PBL, which was evidenced by the flow cytometric analysis, indicating that antibody produced from 3E9 recognizes cell surface antigen specifically expressed in the leukemic cells.

PGE2-receptor subtype EP4-dependent adherence of mastocytoma P-815 cells to matrix components in subcutaneous tissues overlaying inside surface of air pouch cavity in CDF1 mouse

OBJECTIVES

It remains to be fully clarified how adhesion of mast cells is regulated in vivo. We previously reported that PGE2-receptor EP4 stimulated the adhesion of mouse mastocytoma P-815 cells to plate-bound fibronectin. Our purpose in this study is to evaluate the adhesion using a system, which can mimic the in vivo adhesion.

METHODS

P-815 cells were transplanted in an air pouch produced in the transplantable mice, CDF1. The number of cells that adhere to the subcutaneous tissues overlaying the inside cavity surface was determined.

RESULTS

The number of adhered cells was decreased in mice administered with ibuprofen or an EP4 antagonist, ONO AE3-208. A local administration of PGE(2) or a phorbol ester, PMA, increased the number of adhered cells, which was also suppressed in the mice treated with ONO AE3-208.

CONCLUSION

Our results suggest that PGE(2)-mediated adhesion of P-815 cells in the subcutaneous tissues of the air pouch is mediated by the EP4 subtype.

Innervation and activity dependent dynamics of postsynaptic oxidative metabolism

Despite extensive investigations into the mechanisms of aerobic respiration in mitochondria, the spontaneous metabolic activity of individual cells within a whole animal has not been observed in real time. Consequently, little is known about whether and how the level of mitochondrial energy metabolism is regulated in a cell during development of intact systems. Here we studied the dynamics of postsynaptic oxidative metabolism by monitoring the redox state of mitochondrial flavoproteins, an established indicator of energy metabolism, at the developing Drosophila neuromuscular junction. We detected transient and spatially synchronized flavoprotein autofluorescence signals in postsynaptic muscle cells. These signals were dependent on the energy substrates and coupled to changes in mitochondrial membrane potential and Ca2+ concentration. Notably, the rate of autofluorescence signals increased during synapse formation through contact with the motoneuronal axon. This rate was also influenced by the magnitude of synaptic inputs. Thus, presynaptic cells tightly regulate postsynaptic energy metabolism presumably to maintain an energetic balance during neuromuscular synaptogenesis. Our results suggest that flavoprotein autofluorescence imaging should allow us to begin assessing the progress of synapse formation from a metabolic perspective.

In-Situ Formation of a Gel Microbead for Laser Micromanipulation of Microorganisms, DNA, and Viruses

We proposein situformation of gel microbeads made of a thermoreversible hydrogel for indirect laser micromanipulation of microorganisms, DNA, and viruses. Using a 1064 nm laser, we irradiated an aqueous solution mixed with poly-(N-isopropylacrylamide) through a high- magnification lens, thereby forming a gel microbead through heating at the laser focus. The gel microbead, trapped by the laser, was used to indirectly manipulate micro- and nano-scale samples. Laser tweezers stably handle micro-scale object ranging from several tens of nm to several hundreds of µm. This cannot be done with nano-scale objects of a few nm, however, due to laser beam heating. We demonstrate how to manipulate microorganisms, DNA, and viruses indirectly using a gel microbead made from an aqueous poly-(N-isopropylacrylamide) solution. We reduced laser power for gel microbead formation, and used the gel microbead trapped by the laser to manipulate microorganisms, DNA, and viruses.

Membrane orientation of the precursor 74-kDa form of L-histidine decarboxylase

OBJECTIVE

We previously demonstrated that, when expressed in COS-7 cells, L-histidine decarboxylase (HDC), which has neither an amino terminal signal sequence nor a hydrophobic membrane anchor, was localized in the endoplasmic reticulum (ER), although its orientation in the membrane remains to be clarified.

METHODS & RESULTS

Protease digestion and immunofluorescence analyses of the cells, of which plasma membrane was selectively permeabilized, revealed that the amino terminal 50-kDa portion of HDC is hardly accessible to proteases and antibodies added exogenously from the cytosolic side. Green fluorescent protein fused with the carboxyl terminal 20-kDa region of HDC at its carboxyl terminus exhibited the same characteristics as native HDC.

CONCLUSION

These results indicate that HDC is tightly associated with the ER membrane with its carboxyl terminal region exposed on the cytosolic side.

On chip single-cell separation and immobilization using optical tweezers and thermosensitive hydrogel

A novel approach appropriate for rapid separation and immobilization of a single cell by concomitantly utilizing laser manipulation and locally thermosensitive hydrogelation is proposed in this paper. We employed a single laser beam as optical tweezers for separating a target cell and locating it adjacent to a fabricated, transparent micro heater. Simultaneously, the target cell is immobilized or partially entrapped by heating the thermosensitive hydrogel with the micro heater. The state of the thermosensitive hydrogel can be switched from sol to gel and gel to sol by controlling the temperature through heating and cooling by the micro heater. After other unwanted cells are removed by the high-speed cleaning flow in the microchannel, the entrapped cell is successfully isolated. It is possible to collect the immobilized target cell for analysis or culture by switching off the micro heater and releasing the cell from the entrapment. We demonstrated that the proposed approach is feasible for rapid manipulation, immobilization, cleaning, isolation and extraction of a single cell. The experimental results are shown here.

Isolation and extraction of target microbes using thermal sol-gel transformation

We developed a novel separation method for random screening of target microorganisms from a large heterogeneous population by using a local viscosity control. A thermal sol-gel transformation material is mixed with the sample liquid and we controlled the state from sol to gel and gel to sol reversibly based on the temperature change controlled by heating of the microelectrode with the electric current and focused laser irradiation near the target. The selected microorganisms are fixed on the bottom plate by gel, since the viscosity around the target is temporally increased by the local heating by the focused laser. The other objects are easily washed away by the cleaning flow in the microchamber. Process of fixation, cleaning, isolation and extraction of the target microbe was possible in very short time. Based on this method, two separation systems are developed and basic experimental results of fixation and isolation of targets are shown.

Mouse mammary epithelial histamine system

Histamine is suggested to play a role in mammary gland growth regulation, differentiation and functioning during pregnancy and lactation. Two pools of histamine are thought to be involved in these processes: mastocyte- and epithelial cell related histamine. In the present study we focused on epithelial cells. Immunohistochemistry has shown that the epithelial cells positive for histamine and L-histidine decarboxylase (HDC), the primary enzyme regulating histamine biosynthesis, were mainly found in cells forming alveolar structures in the mammary gland. Cultured primary mouse mammary epithelial cells (MMEC) expressed strong HDC immunoreactivity, especially dividing cells and non-differentiated ones. Histidine decarboxylase activity undergoes significant changes during pregnancy and lactation. Pregnancy associated intensive growth of the mammary gland coincided with an increase and the first days of lactation with a decrease of HDC protein expression. Binding studies with mammary tissue membranes and epithelial cell membranes revealed the presence of H1 and H3 but not H2 receptors. Summarizing, our data have shown that mammary epithelial cells are capable of synthesizing and excreting histamine and they bear histamine receptors. These findings further substantiate the role of histamine in mammary gland physiology.

Search for supernova relic neutrinos at Super-Kamiokande

A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type antineutrinos that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, an upper bound of 1.2 macro nu(e) cm(-2) s(-1) was set for the supernova relic neutrino flux in the energy region E(nu)>19.3 MeV.

Expanded parietal cell pool in transgenic mice unable to synthesize histamine

BACKGROUND

The histidine decarboxylase enzyme (HDC) is responsible for the synthesis of histamine in mammals. Histidine decarboxylase-deficient (HDC-/-) mice have recently been developed by targeted mutation of the HDC gene.

METHODS

The impact of prolonged histamine deficiency was studied on gastric morphology (by immunohistochemistry and morphometry), gastric acid secretion (by a wash-through method for basal gastric acid secretion and by pylorus ligation for stimulated gastric acid secretion) and gastrin levels (by radioimmunoassay) in homozygous HDC-/- mice kept on a low-histamine diet.

RESULTS

A double maximal gastric acid secretory response was found in knockouts after exogenous histamine administration. In contrast, the gastric acid secretion was significantly reduced after gastrinergic and cholinergic stimulation in the absence of histamine. The oxynthic gland area of HDC-/- mice was thickened with an increased parietal cell count compared to wild types. Substantially elevated serum and antral tissue gastrin levels of HDC-/- mice could be possible indications of both an expanded parietal cell mass and/or an increased histamine-induced maximal gastric acid secretory capacity of this genotype.

CONCLUSIONS

These data suggest that not enough compensatory mechanisms develop in HDC-/- mice during a prolonged low-histamine diet to maintain/restore normal gastric acid secretion. An expanded parietal cell pool was also demonstrated in HDC-/- mice kept on a low-histamine diet, probably caused by a trophic effect of sustained hypergastrinaemia. The HDC-/- strain is a suitable model for studying the effects of achlorhydria and consequent hypergastrinaemia as an approach to human conditions such as atrophic gastritis or long-term antisecretory therapies.

Histidine decarboxylase deficiency in gene knockout mice elevates male sex steroid production

Histamine is synthesized in cells by histidine decarboxylase (HDC). HDC-deficient knockout (KO) mice lack functional HDC and histamine in the tissues. In the present study we used this in vivo model for studying the role of HDC deficiency in the regulation of male steroid hormone metabolism. In agreement with earlier studies showing the lack of effects of central histamine on the basal secretion of gonadotrope hormones, we found no difference with in situ hybridization in the expression of GnRH in the hypothalamus of wild type and KO mice. The tissue concentrations of testosterone and several androgenic steroids were significantly elevated in the testes but not in the adrenal glands of HDC-KO mice. In contrast, serum estradiol levels failed to show a significant difference between the two groups. The weight of the testes was significantly smaller in both 7-day-old and adult KO mice. The ultrastructure of the adult testis indicated elevated steroid synthesis with more tightly coiled membranous whorls in Leydig cells. The present results suggest that changes in reproductive functions and sex steroid secretion in male HDC-KO mice are not due to altered hypothalamic GnRH expression but are probably related to definite modifications during fetal development of KO mice reinforced later by the lack of the effect of peripheral histamine. This may provide in vivo evidence that peripheral histamine is an important regulatory factor of male gonadal development during embryogenesis and of sex steroid metabolism later in adulthood.

Separation of Target Microbe by Laser Manipulation and Flow Control

We developed random separation of single microorganisms, such as living cells and microbes, in a microfluid device under microscopy using laser manipulation and microchannel flow. The main flow in the microchannel splits at the exit of the sample chamber. One flow goes to the extraction port with high speed to extract the target. Another flow goes to the drain port. The target was transported by laser manipulation from the sample chamber to put on the main flow. Since the force balance of the laser-trapped object is important for stable manipulation of the target, we propose separation point control around the sample chamber exit. Pressure balance was adjusted and the separation point was controlled. Some preliminary experiments are conducted to show effectiveness. The target was trapped by the laser, transported to the main flow around the split area through stagnation, and was extracted from the extraction port. Separation time was reduced less than 10 seconds and the success of separation improved 80%.

Expression of apoptosis in placentae from mice lacking the prostaglandin F receptor

This study aimed to investigate the changes in apoptosis in the placenta and decidua of pregnant mice lacking the prostaglandin F receptor. Mouse placentae were removed from fetuses on days 10-23 of pregnancy. Apoptotic cells were examined by a DNA fragmentation assay and the terminal deoxynucleotidyl transferase-mediated dUDP nick end-labelling (TUNEL) technique. The placenta and decidual weight increased before day 18 and 14 of pregnancy, and then decreased with gestational day. After day 19, the fetuses gradually died in the uterus. All fetuses died in the uterus on day 23 of pregnancy. The number of apoptosis was not significantly different between wild type and FP-deficient mice before day 18 of pregnancy by DNA fragmentation and TUNEL staining. The DNA fragmentation was always more pronounced in decidual tissue on each day of pregnancy. DNA laddering on placentae was more extensive on day 22 than day 18. In placenta, most TUNEL-positive cells were detected in trophoblast and stromal cells. A higher intensity of apoptotic cells was in the decidual basalis. The main area was the centre of the decidual basalis, and was in decrease toward to margin of placenta. The index of TUNEL positive cells increased as gestation progressed toward termination. Especially, it was prominent in the placentae on day 22 compared with that day 18 of pregnancy. The increased TUNEL-positive staining in syncytiotrophoblast surface was found in placenta at post-term, compared with those at term. Apoptosis may provide insights into both normal placental development and placental dysfunction during an abnormal pregnancy from post-term pregnancy.

Design and synthesis of non-peptidic inhibitors for the Syk C-terminal SH2 domain based on structure-based in-silico screening

Structure-based in-silico screening was carried out for the Syk C-terminal SH2 domain. Fragments that could interact with the pY or pY+1 pockets were selected by our in-silico screening. After tethering two fragments bound to these pockets, we have designed and synthesized new compounds that show favorable interaction with the pY+3 pocket. One such compound, having a cyclohexylmalonic acid moiety identified as a novel potent phosphotyrosyl mimetic, exhibited an affinity comparable to that of the monophosphorylated ligand peptide.

Extensive methylation of hMLH1 promoter region predominates in proximal colon cancer with microsatellite instability

BACKGROUND & AIMS

Methylation of the hMLH1 promoter region has been suggested to cause microsatellite instability (MSI) in sporadic colorectal carcinoma (CRC). We studied the methylation profile in a wide region of the hMLH1 promoter and compared with the hMLH1 protein expression and MSI status in 88 cases of sporadic CRC.

METHODS

Na-bisulfite treatment and polymerase chain reaction single-strand conformation polymorphism analysis was performed using 5 sets of polymerase chain reaction primers spanning the promoter region of the hMLH1 to examine methylation status. Results were compared with immunostaining using anti-hMLH1 monoclonal antibody and MSI status of the tumor samples.

RESULTS

Methylation status was classified as full or partial methylation. Full methylation indicates the methylation of all CpG sites in the examined regions. Methylation of the hMLH1 promoter was observed in 88.9% (16 of 18) of CRCs showing high frequency MSI (MSI-H), among which 89% (14 of 16) had full methylation with reduced hMLH1 protein expression. All cases showing full methylation were proximal colon tumors with MSI-H. In cases with partial methylation, only the upstream region of the hMLH1 promoter was methylated. Partial methylation was also shown in 33.3% (6 of 18) of the normal mucosa of MSI-H cases. Frequencies of methylation were significantly correlated with female gender (P = 0.0009) and aging (P = 0.007).

CONCLUSIONS

Full methylation of the hMLH1 promoter region and subsequent gene inactivation may play a crucial role in the carcinogenesis of MSI-H CRCs in the proximal colon. Methylation upstream of the hMLH1 promoter appears to be an early event in the carcinogenesis of MSI-H tumors.

Observation of a (6)(LambdaLambda)He double hypernucleus

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Production of (4)(double Lambda)H hypernuclei

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Increased bleeding tendency and decreased susceptibility to thromboembolism in mice lacking the prostaglandin E receptor subtype EP(3)

BACKGROUND

Among the prostanoids, thromboxane (TX) A(2) is a potent stimulator of platelets, whereas prostaglandin (PG) I(2) inhibits their activation. The roles of PGE(2) in the regulation of platelet function have not been established, however, and the contribution of PGE(2) in hemostasis and thromboembolism is poorly understood. The present study was intended to clarify these roles of PGE(2) by using mice lacking the PGE(2) receptor subtype 3 (EP(3)(-/-) mice).

METHODS AND RESULTS

Expression of mRNAs for EP(3) in murine platelets was confirmed by quantitative reverse transcription-polymerase chain reaction. PGE(2) and AE-248, a selective EP(3) agonist, showed concentration-dependent potentiation of platelet aggregation induced by U46619, a TXA(2) receptor agonist, although PGE(2) alone could not induce aggregation. PGE(2) and AE-248 increased cytosolic calcium ion concentration ([Ca(2+)](i)), and AE-248 inhibited the forskolin-induced increase in cytosolic cAMP concentration ([cAMP](i)), suggesting G(i) coupling of EP(3). The potentiating effects of PGE(2) and AE-248 on platelet aggregation along with their effects on [Ca(2+)](i) and [cAMP](i) were absent in EP(3)(-/-) mice. In vivo, the bleeding time was significantly prolonged in EP(3)(-/-) mice. Moreover, when mice were challenged intravenously with arachidonic acid, mortality and thrombus formation in the lung were significantly reduced in EP(3)(-/-) mice.

CONCLUSIONS

- PGE(2) potentiated platelet aggregation induced by U46619 via EP(3) by increasing [Ca(2+)](i), decreasing [cAMP](i), or both. This potentiating action of PGE(2) via EP(3) is essential in mediating both physiological and pathological effects of PGE(2) in vivo.

Mice lacking histidine decarboxylase exhibit abnormal mast cells

Histidine decarboxylase (HDC) synthesizes histamine from histidine in mammals. To evaluate the role of histamine, we generated HDC-deficient mice using a gene targeting method. The mice showed a histamine deficiency and lacked histamine-synthesizing activity from histidine. These HDC-deficient mice are viable and fertile but exhibit a decrease in the numbers of mast cells while the remaining mast cells show an altered morphology and reduced granular content. The amounts of mast cell granular proteases were tremendously reduced. The HDC-deficient mice provide a unique and promising model for studying the role of histamine in a broad range of normal and disease processes.

Major roles of prostanoid receptors IP and EP(3) in endotoxin-induced enhancement of pain perception

To know the roles of prostaglandin I (IP) and prostaglandin E (EP) receptors in pain perception, we compared the acetic acid-induced writhing response in mice deficient in prostaglandin receptors, i.e. IP, EP(1,) EP(2,) EP(3,) or EP(4,) with or without lipopolysaccharide (LPS) pretreatment. Without LPS pretreatment, IP-receptor deficient mice showed a significantly smaller number of responses, as previously reported, whereas mice deficient in any of the EP-receptor subtypes showed a number of writhings similar to those of wild-type mice. When mice were pretreated with LPS for 24 hr to induce cyclooxygenase-2 expression, the wild-type as well as EP(1)-, EP(2)-, or EP(4)-receptor-deficient mice showed a similar enhanced writhing response, whereas IP- and EP(3)-receptor-deficient mice had a significantly less enhanced number of writhings. These results indicate that IP and EP(3) are the major prostaglandin receptors mediating the enhanced acetic acid-induced writhing response in mice pre-exposed to LPS, i.e. in endotoxin-enhanced inflammatory nociception.

DNA variants of BAT-25 in Japanese, a locus frequently used for analysis of microsatellite instability

BAT-25 is a DNA marker, intragenic to the c-kit protooncogene, assigned to 4q12, containing a polythymine tract, mostly repeats of 25 poly(T) (T25). The BAT-25 locus is frequently used in the analysis of microsatellite instability (MSI) in cancer tissues. The number of poly(T) repeats at BAT-25 is reported to be quasi-monomorphic and this property permits the easy identification of the MSI status. We report DNA variants of BAT-25, in one patient with hereditary nonpolyposis colorectal cancer presenting T21 and T25 alleles and another carrying T18 and T25 alleles in the analysis of 100 normal Japanese donors. Observed allelic frequencies were 0.5% for both T21 and T18 alleles. So far, DNA variants of BAT-25 locus have been reported in African Americans with relatively high frequencies, but not in Japanese.

Regulation of TNFalpha and interleukin-10 production by prostaglandins I(2) and E(2): studies with prostaglandin receptor-deficient mice and prostaglandin E-receptor subtype-selective synthetic agonists

To know which receptors of prostaglandins are involved in the regulation of TNFalpha and interleukin 10 (IL-10) production, we examined the production of these cytokines in murine peritoneal macrophages stimulated with zymosan. The presence of PGE(2) or the PGI(2) analog carbacyclin in the medium reduced the TNFalpha production to one-half, whereas IL-10 production increased several fold; and indomethacin caused the reverse effects, suggesting that endogenous prostaglandins may have a regulatory effect on the cytokine production. Among prostaglandin E (EP) receptor-selective synthetic agonists, EP2 and EP4 agonists caused down-regulation of the zymosan-induced TNFalpha production, but up-regulation on the IL-10 production; while EP1 and EP3 agonists showed no effect. Macrophages harvested from prostaglandin I (IP) receptor-deficient mice showed the up- and down-regulatory effects on the cytokine production by the EP2 and EP4 agonists or PGE(2), but no effect was obtained by carbacyclin. On the contrary, macrophages from EP2-deficient mice showed the effect by PGE(2), carbacyclin, and the EP4 agonist, but not by the EP2 agonist; and the cells from EP4-deficient mice showed the effect by PGE(2), carbacyclin, and EP2 agonist, but not by the EP4 agonist. These functional effects of prostaglandins well accorded with the mRNA expression of TNFalpha and IL-10 when such expression was examined by the RT-PCR method. The peritoneal macrophages from normal mice expressed IP, EP2, and EP4 receptors, but not EP1 and EP3, when examined by RT-PCR. Thus the results suggest that PGI(2) and PGE(2) generated simultaneously with cytokines by macrophages treated with zymosan may influence the cytokine production through IP, EP2, and EP4 receptors.

Histamine deficiency suppresses murine haptoglobin production and modifies hepatic protein tyrosine phosphorylation

Histidine decarboxylase (HDC) synthesizes endogenous histamine from histidine in mammals. HDC-deficient mice (HDC-/-), if kept on a histamine-free diet, have no histamine in their tissues. HDC-/- mice show multiple phenotypes. In this study we show that both the constitutively expressed and turpentine-induced level of an acute-phase protein, haptoglobin, is significantly lower in the serum of HDC-/- mice compared to that of wild-type animals. This effect was abolished if HDC gene-targeted mice received histamine-rich food. No differences were found when lipopolysaccharide (LPS) was used to induce the acute-phase reaction. Using specific antibodies to phosphorylated tyrosine, we showed that protein tyrosine phosphorylation (Y-P) of approximately 50- and 26- to 27-kDa liver proteins is significantly decreased in HDC-/- mice, but that the difference was largely diminished if the animals were kept on a histamine-rich diet, suggesting that the phenotype with lower haptoglobin production is diet inducible. Upon in vivo treatment with LPS, Y-P band intensity decreased, regardless of the presence or absence of histamine. Identification of elements of the signalling pathway with decreased phosphorylation may elucidate the molecular background of the effect of endogenous histamine in the hepatic acute-phase reaction.

[Reproduction physiology and prostanoids]

Prostanoids, which consist of prostaglandins (PGs) and thromboxane, are produced from arachidonic acid by cyclooxygenases (COXs) as a rate-limiting step, and they exert various biological actions. Classically, prostanoids are suspected to be closely related to female reproductive processes such as ovulation, luteolysis and uterine contraction, as well as pathological processes such as fever generation and pain modulation. Recently the cDNA cloning of a series of prostaglandin-synthesizing enzymes and receptors enabled us to clarify which isoform or subtype is involved in each reproductive process by generating individual gene-deficient mice. In late pregnancy, PGF2 alpha synthesized by COX-1 is essential for induction of parturition via luteolysis. Furthermore, impaired induction of COX-2 in the myometrium of PGF2 alpha receptor-deficient mice is accompanied with loss of parturition, suggesting that COX-2 is presumably responsible for producing uterotonic PGs. In early pregnancy, PGE2 synthesized by COX-2 induces the expansion of cumulus cells through EP2 receptor and contributes to ovulation and fertilization. These results may be useful in not only developing novel drugs in the reproductive area but also understanding and overcoming harmful reproductive side effects of classical and novel drugs in non-reproductive areas.

Upregulation of histidine decarboxylase mRNA expression in scleroderma skin

The involvement of histamine in the pathogenesis of systemic sclerosis (SSc) has been suggested. Possible involvement of histamine and histidine decarboxylase (HDC), the synthesizing enzyme for histamine, in the formation of the skin abnormalities in SSc was studied. Skin histamine concentrations in SSc were significantly lower than in normal controls (P < 0.02). In situ hybridization with an HDC probe revealed that the expression of the HDC gene in SSc was greater than in normal controls. The number of cells and the mean grain number per cell expressing HDC mRNA were both significantly greater in SSc than in normal controls (both P < 0.01). These results show a reduction in histamine concentration and an elevated HDC gene expression in SSc skin, indicating an increase in both histamine release and HDC gene expression. The upregulation of histamine turnover appears to be involved in the formation of the skin abnormalities of SSc.