Improvement of biodistribution profile of a radiogallium-labeled, αvβ6 integrin-targeting peptide probe by incorporation of negatively charged amino acids

Objective Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Since αvβ6 integrin has been reported as a promising target for PDAC diagnosis, we previously developed H-Cys(mal-NOTA-67Ga)-(Gly)6-A20FMDV2-NH2 ([67Ga]CG6) as an αvβ6 integrin-targeting probe. Although [67Ga]CG6 specifically binds to αvβ6 integrin-positive xenografts, the uptake of [67Ga]CG6 in the organs surrounding the pancreas, such as the liver and spleen, was comparable to that in the αvβ6 integrin-positive xenografts. We hypothesized that the undesirable accumulation of [67Ga]CG6 in those organs was caused by the positive charges of [67Ga]CG6 (+ 3). In this study, we aimed to decrease [67Ga]CG6 uptake in the liver and spleen by reducing the electric charges of the probe. Methods We synthesized H-Cys(mal-NOTA-67Ga)-(Asp)6-A20FMDV2-NH2 ([67Ga]CD6) and evaluated its affinity to αvβ6 integrin via in vitro competitive binding assay. Isoelectric points of the probes were determined by electrophoresis. Biodistribution study, autoradiography, and immunostaining for β6 integrin were conducted using αvβ6 integrin-positive and negative tumor-bearing mice. Results In vitro competitive binding assay showed that the alteration of the linker had a negligible impact on the affinity of [67Ga]CG6 to αvβ6 integrin. The results of electrophoresis revealed that [67Ga]CG6 was positively charged whereas [67Ga]CD6 was negatively charged. In the biodistribution study, the uptake of [67Ga]CD6 in the αvβ6 integrin-positive xenografts was significantly higher than that in the αvβ6 integrin-negative ones at 60 and 120 min. The uptake of [67Ga]CD6 in the liver and spleen was more than two-fold lower than that of [67Ga]CG6 at both time points. In the immunohistochemistry study, the radioactivity accumulated areas in the autoradiogram of the αvβ6 integrin-positive xenograft roughly coincided with β6 integrin-expressing areas. Conclusion We have successfully reduced the nonspecific uptake in the liver and spleen by altering the linker amino acid from G6 to D6. [67Ga]CD6 overcame the drawbacks of [67Ga]CG6 in its biodistribution

Growth, Yield and Fruit Quality of Tomato as Affected by Root Zone Restriction in Combination with Solar-mediated Fertigation Regime

　Plant growth and fruit development of tomato (Lycopersicon esculentum Mill. cv. House Momotaro) grown in different sized plastic pots (root zone volume, RZV, of 250, 500, 1,000 mL/plant) in combination with high or low rate of drip fertigation (HF and LF) were investigated. In the February-sown experiment, the plants were fertigated with standard to half strength of Ohtsuka-A solution in proportion to solar radiation keeping the ratio of drainage to supplied solution as 10 to 20ｵ, in 500mL- and 250mL-RZV for HF and LF, respectively. Stem and leaf growth decreased with decrease in RZV and the fertigation rate. The decreases were not significant in the distal plant part lower than the 4th inflorescence. The average fruit weight was greater in HF than LF and increased with increase in RZV only for HF. The incidence of blossom-end rot (BER) was more frequent in HF compared to LF and increased with increase in RZV only for LF. Consequently, fruit yield increased with increase in RZV for HF, but it decreased with increase in RZV for LF. Total soluble solid content (TSS) was significantly higher in LF than in HF and increased with decrease in RZV. Qualified fruits, called ‘fruit tomato’ having 8ｵ of TSS or higher, were obtained with 250 to 500mL of RZV in the successive October-sown experiment where the standard solution was supplied throughout. For ‘fruit tomato’ production with a substrate culture system, root zone restriction, in combination with solar-mediated fertigation control, can be a useful and stable stress factor, reducing shoot and fruit growth, but inducing fruit sugar accumulation and reducing BER incidence simultaneously

Characterization of Highly Pathogenic Avian Influenza Virus A(H5N6), Japan, November 2016

Highly pathogenic avian influenza viruses (HPAIVs) A(H5N6) were concurrently introduced into several distant regions of Japan in November 2016. These viruses were classified into the genetic clade 2.3.4.4c and were genetically closely related to H5N6 HPAIVs recently isolated in South Korea and China. In addition, these HPAIVs showed further antigenic drift

Support for UNRWA's survival

The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland

Introgression of Drosophila simulans Nuclear Pore Protein 160 in Drosophila melanogaster Alone Does Not Cause Inviability but Does Cause Female Sterility

We have been analyzing genes for reproductive isolation by replacing Drosophila melanogaster genes with homologs from Drosophila simulans by interspecific backcrossing. Among the introgressions established, we found that a segment of the left arm of chromosome 2, Int(2L)S, carried recessive genes for hybrid sterility and inviability. That nuclear pore protein 160 (Nup160) in the introgression region is involved in hybrid inviability, as suggested by others, was confirmed by the present analysis. Male hybrids carrying an X chromosome of D. melanogaster were not rescued by the Lethal hybrid rescue (Lhr) mutation when the D. simulans Nup160 allele was made homozygous or hemizygous. Furthermore, we uniquely found that Nup160 is also responsible for hybrid sterility. Females were sterile when D. simulans Nup160 was made homozygous or hemizygous in the D. melanogaster genetic background. Genetic analyses indicated that the D. simulans Nup160 introgression into D. melanogaster was sufficient to cause female sterility but that other autosomal genes of D. simulans were also necessary to cause lethality. The involvement of Nup160 in hybrid inviability and female sterility was confirmed by transgene experiment

The Sox2 promoter-driven CD63-GFP transgenic rat model allows tracking of neural stem cell-derived extracellular vesicles

Extracellular vesicles (EVs) can modulate microenvironments by transferring biomolecules, including RNAs and proteins derived from releasing cells, to target cells. To understand the molecular mechanisms maintaining the neural stem cell (NSC) niche through EVs, a new transgenic (Tg) rat strain that can release human CD63-GFP-expressing EVs from the NSCs was established. Human CD63-GFP expression was controlled under the rat Sox2 promoter (Sox2/human CD63-GFP), and it was expressed in undifferentiated fetal brains. GFP signals were specifically observed in in vitro cultured NSCs obtained from embryonic brains of the Tg rats. We also demonstrated that embryonic NSC (eNSC)-derived EVs were labelled by human CD63-GFP. Furthermore, when we examined the transfer of EVs, eNSC-derived EVs were found to be incorporated into astrocytes and eNSCs, thus implying an EV-mediated communication between different cell types around NSCs. This new Sox2/human CD63-GFP Tg rat strain should provide resources to analyse the cell-to-cell communication via EVs in NSC microenvironments