Improvement of short straws for sperm cryopreservation: installing an air-permeable filter facilitates handling.

Saving space for sperm cryopreservation would aid mouse genetics research. We previously developed the ST (sperm freezing in ShorT STraw to reduce STorage space) method for cryopreserving mouse sperm in a smaller storage space than conventional methods. However, our ST method has two drawbacks: difficulties during freeze-thaw procedures and the potential risk of sperm loss during storage.

Production of an anti-angiogenic factor sFLT1 is suppressed via promoter hypermethylation of FLT1 gene in choriocarcinoma cells.

Background: Soluble Fms-like tyrosine kinase-1 (sFLT1) as an anti-angiogenic factor is abundantly expressed in placental trophoblasts. Choriocarcinoma, a malignant tumor derived from trophoblasts, is known to be highly angiogenic and metastatic. However, the molecular mechanism underlying angiogenesis in choriocarcinoma pathogenesis remains unclear.

Freezing sperm in short straws reduces storage space and allows transport in dry ice.

Efficient cryopreservation and transportation of mouse sperm are among the most desirable strategies for current and future research on mouse genetics. However, the current method for sperm cryopreservation uses an 11-cm plastic straw, which is a bulky and fragile container. Developing an alternative to overcome the limitations associated with this method would accelerate biomedical research.

Suppression of HIV-1 Infectivity by Human Glioma Cells.

HIV-1 infection to the central nervous system (CNS) is very common in AIDS patients. The predominant cell types infected in the brain are monocytes and macrophages, which are surrounded by several HIV-1-resistant cell types, such as astrocytes, oligodendrocytes, neurons, and microvascular cells. The effect of these HIV-1-resistant cells on HIV-1 infection is largely unknown.

Littermate influence on infant growth in mice: comparison of SJL/J and ICR as cotransferred carrier embryos.

In mice, a minimum number of healthy embryos is required to trigger and maintain pregnancy. Therefore, when recovering mouse embryos from a limited litter, one useful technique is to transfer carrier ICR embryos along with the embryos of interest, a technique referred to as cotransfer. In this study, we examined suitable mouse strains for cotransfer with C57BL/6J (B6) embryos in regards to the maintenance of pregnancy, number of pups born, intrauterine growth, and postnatal growth.

CKR-L3, a deletion version CCR6-isoform shows coreceptor-activity for limited human and simian immunodeficiency viruses.

Background: The chemokine receptors (CKRs), mainly CCR5 and CXCR4 function as major coreceptors in infections caused by human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV). Approximately 20 G protein-coupled receptors (GPCRs) have been identified as minor coreceptors, alike CCR6 that we reported recently. Since CKR-L3 is indentified as a natural isoform of CCR6, we attempted in this study to explore the coreceptor function of CKR-L3.

Characterisation of cytoplasmic DNA complementary to non-retroviral RNA viruses in human cells.

The synthesis and subsequent genomic integration of DNA that is complementary to the genomes of non-retroviral RNA viruses are rarely observed. However, upon infection of various human cell lines and primary fibroblasts with the vesicular stomatitis virus (VSV), we detected DNA complementary to the VSV RNA. The VSV DNA was detected in the cytoplasm as single-stranded DNA fully complementary to the viral mRNA from the poly(A) region to the 7-methyl guanosine cap.

CCR6 functions as a new coreceptor for limited primary human and simian immunodeficiency viruses.

More than 12 chemokine receptors (CKRs) have been identified as coreceptors for the entry of human immunodeficiency virus type 1 (HIV-1), type 2 (HIV-2), and simian immunodeficiency viruses (SIVs) into target cells. The expression of CC chemokine receptor 6 (CCR6) on Th17 cells and regulatory T cells make the host cells vulnerable to HIV/SIV infection preferentially. However, only limited information is available concerning the specific role of CCR6 in HIV/SIV infection.

X4-tropic human immunodeficiency virus IIIB utilizes CXCR4 as coreceptor, as distinct from R5X4-tropic viruses.

Human immunodeficiency viruses initiate infections via CCR5 coreceptors and then change their tropism to C-X-C chemokine receptor type 4 (CXCR4), this change being associated with rapid disease progression. HIV-1IIIB, a widely described pure X4-tropic strain, is distinct from R5X4-tropic viruses. In this study, the requirement for amino terminal regions (NTRs) of CXCR4 for entry of HIV-1IIIB virus into host cells was examined and compared to that of R5X4-tropic viruses.

Inhibitory effect of chondroitin sulfate type E on the binding step of human T-cell leukemia virus type 1.

Cell surface heparan sulfate proteoglycans (HSPGs) are involved in the binding and entry of human T-cell leukemia virus type 1 (HTLV-1) into host cells, while sulfated polysaccharides such as heparin inhibit HTLV-1 infection. Chondroitin sulfate proteoglycans (CSPGs) are classified as another major type of proteoglycans. Here, we examined the effect of four types of chondroitin sulfate (CS) on HTLV-1 infection.

Ionising irradiation alters the dynamics of human long interspersed nuclear elements 1 (LINE1) retrotransposon.

It is important to identify the mechanism by which ionising irradiation induces various genomic alterations in the progeny of surviving cells. Ionising irradiation activates mobile elements like retrotransposons, although the mechanism of its phenomena consisting of transcriptions and insertions of the products into new sites of the genome remains unclear. In this study, we analysed the effects of sparsely ionising X-rays and densely ionising carbon-ion beams on the activities of a family of active retrotransposons, long interspersed nuclear elements 1 (L1).

Entry of human T-cell leukemia virus type 1 is augmented by heparin sulfate proteoglycans bearing short heparin-like structures.

Three molecules have been identified as the main cellular factors required for binding and entry of human T-cell leukemia virus type 1 (HTLV-1): glucose transporter 1 (GLUT1), heparan sulfate (HS), and neuropilin 1 (NRP-1). However, the precise mechanism of HTLV-1 cell tropism has yet to be elucidated. Here, we examined the susceptibilities of various human cell lines to HTLV-1 by using vesicular stomatitis virus pseudotypes bearing HTLV-1 envelope proteins.

Lack of the trans-receptor mechanism of HIV-1 infection: CD4- and coreceptor-independent incorporation of HIV-1-resistant cells into syncytia induced by HIV-1.

Human immunodeficiency virus type 1 (HIV-1) infects cells through an interaction of HIV-1 envelope protein with CD4 and an appropriate coreceptor on target cells. This interaction often leads to cell fusion, and formation of syncytia. HIV-1-resistant cells expressing either CD4 or a coreceptor are often surrounding HIV-1-susceptible cells, expressing both CD4 and a compatible coreceptor, in vivo.

Human T-cell leukemia viruses are highly unstable over a wide range of temperatures.

The biological properties of human T-cell leukemia virus type I (HTLV-I) and HTLV type II (HTLV-II) are not well elucidated as cell-free viruses. We established new assay systems to detect the infectivity of cell-free HTLVs and examined the stability of cell-free HTLVs at different temperatures. HTLVs lost infectivity more rapidly than did bovine leukemia virus (BLV), which is genetically related to HTLVs.

Tax1-expressing feline 8C cells are useful to monitor the life cycle of human T-cell leukemia virus type I.

Extremely low infectivity has hampered direct (cell-free) infection studies of human T-cell leukemia virus type I (HTLV-I). In order to break through this barrier, we examined the susceptibility of many kinds of cells to HTLV-I and found a feline kidney cell line, 8C, that is highly susceptible to HTLV-I and produced remarkable amounts of infectious progeny viruses. Tax1 protein encoded by HTLV-I is known as a transcription activator for viral and cellular genes.

Short communication: identification of the conformational requirement for the specificities of coreceptors for human and simian immunodeficiency viruses.

More than 10 G protein-coupled receptors (GPCRs) work as coreceptors for human and simian immunodeficiency viruses (HIVs/SIVs); however, structural features critical for coreceptor activity have not been identified. Our objective was to elucidate the structural requirement of coreceptor activities. Amino-terminal regions (NTRs), extracellular loops (ECLs), and the undecapeptidyl arch (UPA) in the second ECL have been shown to be important for coreceptor function.

Irradiation with carbon ion beams induces apoptosis, autophagy, and cellular senescence in a human glioma-derived cell line.

Purpose: We examined biological responses of human glioma cells to irradiation with carbon ion beams (C-ions).

Methods And Materials: A human glioma-derived cell line, NP-2, was irradiated with C-ions. Apoptotic cell nuclei were stained with Hoechst 33342.

A formylpeptide receptor, FPRL1, acts as an efficient coreceptor for primary isolates of human immunodeficiency virus.

Background: More than 10 members of seven-transmembrane G protein-coupled receptors (GPCRs) have been shown to work as coreceptors for human immunodeficiency virus type 1 (HIV-1), HIV type 2 (HIV-2), and simian immunodeficiency viruses (SIVs). As a common feature of HIV/SIV coreceptors, tyrosine residues are present with asparagines, aspartic acids or glutamic acids in the amino-terminal extracellular regions (NTRs). We noticed that a receptor for N-formylpeptides, FPRL1, also contains two tyrosine residues accompanied by glutamic acids in its NTR.

Isolation of the feline alpha1,3-galactosyltransferase gene, expression in transfected human cells and its phylogenetic analysis.

The enzyme alpha 1,3-galactosyltransferase (alpha1,3-GT), which catalyzes synthesis of terminal alpha-galactosyl epitopes (Gal alpha1,3Gal beta1-4GlcNAc-R), is produced in non-primate mammals, prosimians and new-world monkeys, but not in old-world monkeys, apes and humans. We cloned and sequenced a cDNA that contains the coding sequence of the feline alpha1,3-GT gene. Flow cytometric analysis demonstrated that the alpha-galactosyl epitope was expressed on the surface of a human cell line transduced with an expression vector containing this cDNA, and this alpha-galactosyl epitope expression subsided by alpha-galactosidase treatment.

Formation of vesicular stomatitis virus pseudotypes bearing surface proteins of hepatitis B virus.

It has been difficult to propagate and titrate hepatitis B virus (HBV) in tissue culture. We examined whether vesicular stomatitis virus (VSV) pseudotypes bearing HBV surface (HBs) proteins infectious for human cell lines could be prepared. For this, expression plasmids for three surface proteins, L, M, and S, of HBV were made.

The synthetic peptide derived from the NH2-terminal extracellular region of an orphan G protein-coupled receptor, GPR1, preferentially inhibits infection of X4 HIV-1.

Several G protein-coupled receptors (GPCRs) serve as co-receptors for entry of human immunodeficiency virus type 1 (HIV-1) into target cells. Here we report that a synthetic peptide derived from the NH2-terminal extracellular region of an orphan GPCR, GPR1 (GPR1ntP-(1-27); MEDLEETLFEEFENYSYDLDYYSLESC), inhibited infection of not only an HIV-1 variant that uses GPR1 as a co-receptor, but also X4, R5, and R5X4 viruses. Among these HIV-1 strains tested, viruses that can utilize CXCR4 as their co-receptors were preferentially inhibited.

Human T-cell leukaemia virus type I is highly sensitive to UV-C light.

The biological characteristics of human T-cell leukaemia virus type I (HTLV-I) are not yet well understood. UV light C (UV-C) sensitivity of HTLV-I was studied using a newly established infectivity assay: infection with cell-free HTLV-I dose-dependently induced syncytial plaques in cat cells transduced with the tax1 gene of HTLV-I. HTLV-I was inactivated by a much lower UV dose than bovine leukaemia virus (BLV).

Expression of inducible nitric oxide synthase and elevation of tyrosine nitration of a 32-kilodalton cellular protein in brain capillary endothelial cells from rats infected with a neuropathogenic murine leukemia virus.

PVC-211 murine leukemia virus (MuLV) is a neuropathogenic variant of Friend MuLV (F-MuLV) which causes a rapidly progressive spongiform neurodegenerative disease in rodents. The primary target of PVC-211 MuLV infection in the brain is the brain capillary endothelial cell (BCEC), which is resistant to F-MuLV infection. Previous studies have shown that changes in the envelope gene of PVC-211 MuLV confer BCEC tropism to the virus.