STAT (signal transducers and activators of transcription) proteins are transcription factors which are activated by phosphorylation on tyrosine residues upon stimulation by cytokines. Seven members of the STAT family are known, including the closely related STAT5A and STAT5B, which are activated by various cytokines. Except for prolactin-dependent ␤-casein production in mammary gland cells, the biological consequences of STAT5 activation in various systems are not clear. We applied PCR-driven random mutagenesis and a retrovirus-mediated expression screening system to identify constitutively active forms of STAT5. By this strategy, we have identified a constitutively active STAT5 mutant which has two amino acid substitutions; one is located upstream of the putative DNA binding domain (H299R), and the other is located in the transactivation domain (S711F). The mutant STAT5 was constitutively phosphorylated on tyrosine residues, localized in the nucleus, and was transcriptionally active. Expression of the mutant STAT5 partially dispenses with interleukin 3 (IL-3) as a growth stimulant of IL-3-dependent cell lines. Further analyses of the mutant STAT5 have demonstrated that both of the mutations are required for nuclear localization, efficient transcriptional activation, and induction of IL-3-independent growth of an IL-3-dependent cell line, Ba/F3, and have indicated that a molecular basis for the constitutive activation is the stability of the phosphorylated form of the mutant STAT5.Stimulation of cytokine receptors leads to activation of multiple signal transduction pathways, including the Ras-Raf-MEK-mitogen-activated protein kinase (MAPK) and the JAK-STAT pathways (14,28,34,42,44). The latter signaling pathway was originally found downstream of the interferon receptors and is now recognized as a common pathway downstream of most cytokine receptors. Upon stimulation with cytokines, receptor-associated JAKs are activated and phosphorylate STAT factors on tyrosine residues. The phosphorylated STAT molecules then form homo-or heterodimers through SH2-mediated interactions and translocate into nuclei to activate transcription of various target genes. Seven members of the STAT family (STAT1 through 4, -5A, -5B, and -6) are known; STAT5A and STAT5B are closely related. With the exception of STAT4 and STAT6, which were shown to be specifically activated by only one or two cytokines, interleukin 12 (IL-12) or both IL-4 and IL-13, respectively (13, 15), most of the other STATs are activated by multiple cytokines. In particular, both STAT5A and STAT5B are activated by numerous cytokines, including prolactin, IL-2, IL-3, IL-5, IL-7, granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, M-CSF, erythropoietin (Epo), thrombopoietin, and growth hormone (GH).Using the receptor for the human GM-CSF as a model system, members of our group previously showed that activation of the Ras-Raf-MEK-MAPK pathway inhibits apoptosis while the region of the GM-CSF receptor, which is responsible for activation of JAK2 and STAT5 an...

We previously established a high-efficiency, retrovirus-mediated expression cloning method. Using this system, we now have developed an expression cloning method (FL-REX; fluorescence localization-based retrovirus-mediated expression cloning) in which cDNAs can be isolated based on the subcellular localization of their protein products. Complementary DNAs generated from mRNA using random hexamers were fused to the cDNA of green fluorescent protein (GFP) in the pMX retrovirus vector. The resulting cDNA-GFP fusion library was transfected into retrovirus-packaging cells, and the derived retroviruses were used to infect NIH 3T3 cells. Infected cells then were screened to identify cDNAs of interest through the subcellular localization of the GFP-fusion products. Using FL-REX, we have identified 25 cDNAs, most of which showed reasonable subcellular localization as GFP-fusion proteins, indicating that FL-REX is useful for identification of proteins that show specific intracellular localization.

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We report a patient with congenital Chagas disease in Japan. This report reemphasizes the role of neglected and emerging tropical diseases in the era of globalization. It also indicates the need for increased vigilance for detecting Chagas disease in non–disease-endemic countries.

Background There are no reports on the prevalence of Chagas disease in Japan. Furthermore, screening programs and access to diagnosis and treatment have not been established. This study aimed to clarify the prevalence of Chagas disease among suspected cases in Japan and provide the reference data required for disease control. Methods Seventeen patients with suspected Chagas disease in Japan between 2012 and 2017 were included in the study. Patients were diagnosed with Chagas disease based on the two different serological tests for antibodies to Trypanosoma cruzi . Real-time polymerase chain reaction assay and blood culture techniques were performed to confirm T. cruzi parasitemia. Results Of the 17 patients, 11 (64.7%) were immigrants from Latin America. Ultimately, 6 patients (35.3%) were diagnosed with Chagas disease. Of these 6 patients, median age was 53.5 years, 5 patients were immigrants from Latin American, and 1 was Japanese who had a congenital infection. T. cruzi parasitemia was confirmed in 4 patients (66.7%), and 5 (83.3%) were in the chronic phase (Chagas cardiomyopathy, 4; megacolon, 1). Two patients (33.3%) commenced benznidazole treatment. Conclusion Our study showed that some patients of Chagas disease living in Japan are already in the chronic phase at diagnosis because of substantial diagnostic delays. Further epidemiological studies on the prevalence of Chagas disease and systematic screening programs for the Latin American population are needed.

Water-soluble zinc porphyrins bearing an ammonium group and a phenyl or tertiary butyl group above each porphyrin plane were designed and synthesized. Binding data for amino carboxylates in aqueous solution suggested that these porphyrins recognize the carboxylates on the basis of coordinative, Coulomb, and hydrophobic interactions and that a chiral recognition phenomenon for glycyl-tryptophan anion is derived from the cooperation of these interactions.

This work describes a colorimetric signaling approach for competitive lateral flow immunoassays (LFIAs) enabling sensitive and semiquantitative direct visual result readout in the form of "text", demonstrated on the example of 8-hydroxy-2′-deoxyguanosine (8-OHdG) detection. The distinctive feature of the developed text-displaying LFIA (TD-LFIA) is the test zone system consisting of a combination of two types of inkjet-deposited capture molecules referred to as "mask antigen" and "text antibody", allowing for sensitive turn-on signaling as opposed to the inverse response of conventional competitive LFIAs. The user operation is limited to sample application, followed by direct reading of assay results written in text after approximately 10 min. TD-LFIAs enabled the visual detection of 8-OHdG at concentrations down to 3 ng/mL, which is a 2−3 orders of magnitude lower visual detection limit than that achieved with the corresponding conventional design and is comparable to the existing LFIAs relying on external signal readout equipment. Highly reproducible observer-independent assay performance was confirmed, and the result interpretation is not influenced by sample color and readout timing. Making use of customizable threshold settings for text appearance, a device for semiquantitative assays was developed and successfully applied to the detection of 8-OHdG at four concentration levels (trace, low, medium, and high) in 54 human urine samples within the clinically relevant concentration range. The sensitive and intuitive signaling method of the developed system offers great potential for an alternative competitive LFIA platform suitable for real-world point-of-care testing applications.

BackgroundA simple and accurate molecular diagnostic method for malaria is urgently needed due to the limitations of conventional microscopic examination. In this study, we demonstrate a new diagnostic procedure for human malaria using loop mediated isothermal amplification (LAMP) and the MinION™ nanopore sequencer.MethodsWe generated specific LAMP primers targeting the 18S–rRNA gene of all five human Plasmodium species including two P. ovale subspecies (P. falciparum, P. vivax, P. ovale wallikeri, P. ovale curtisi, P. knowlesi and P. malariae) and examined human blood samples collected from 63 malaria patients in Indonesia. Additionally, we performed amplicon sequencing of our LAMP products using MinION™ nanopore sequencer to identify each Plasmodium species.ResultsOur LAMP method allowed amplification of all targeted 18S–rRNA genes of the reference plasmids with detection limits of 10–100 copies per reaction. Among the 63 clinical samples, 54 and 55 samples were positive by nested PCR and our LAMP method, respectively. Identification of the Plasmodium species by LAMP amplicon sequencing analysis using the MinION™ was consistent with the reference plasmid sequences and the results of nested PCR.ConclusionsOur diagnostic method combined with LAMP and MinION™ could become a simple and accurate tool for the identification of human Plasmodium species, even in resource-limited situations.Electronic supplementary materialThe online version of this article (10.1186/s12879-017-2718-9) contains supplementary material, which is available to authorized users.