Purification of living environments using photocatalysts: inactivation of microorganisms and decomposition of allergens

Many emerging and re-emerging infectious diseases are prevalent, and the number of patients with allergies is increasing. Therefore, the importance of purifying the living environment is increasing. Photocatalysts undergo extreme redox reactions and decompose organic matter upon exposure to the excitation light. In contrast to ultraviolet light and disinfectants, which are standard methods for inactivating viruses and eliminating microorganisms, photocatalysts can decompose toxic substances, such as endotoxins and allergens, rendering them harmless to the human body. Photocatalysts have attracted significant attention as potential antiviral and antimicrobial agents. This review outlines the antiviral, antimicrobial, and anti-allergenic effects of photocatalysts. Especially, we have discussed the inactivation of SARS-CoV-2 in liquids and aerosols, elimination of Legionella pneumophila in liquids, decomposition of its endotoxin, decomposition of cat and dog allergens, and elimination of their allergenicity using photocatalysts. Furthermore, we discuss future perspectives on how photocatalysts can purify living environments, and how photocatalytic technology can be applied to companion animals and the livestock industry.

First characterization of major histocompatibility complex class II DRB3 diversity in cattle breeds raised in Egypt

Genes encoding bovine leukocyte antigen (BoLA) enable the immune system to identify pathogens. Therefore, these genes have been used as genetic markers for infectious and autoimmune diseases as well as for immunological traits in cattle. Although BoLA polymorphisms have been reported in various cattle breeds worldwide, they have not been studied in cattle populations. In this study, we characterized BoLA-DRB3 in two local Egyptian populations and one foreign population using polymerase chain reaction-sequence-based typing (PCR-SBT) method. Fifty-four previously reported BoLA-DRB3 alleles and eight new alleles (BoLA-DRB3*005:08, *015:07, *016:03, *017:04, *020:02:02, *021:03, *164:01, and *165:01) were identified. Alignment analysis of the eight new alleles revealed 89.5-98.7 %, and 81.0-97.5 % nucleotide and amino acid identities, respectively, with the BoLA-DRB3 cDNA clone NR-1. Interestingly, BoLA-DRB3 in Egyptian cattle showed a high degree of allelic diversity in native (na = 28, hE > 0.95), mixed (na = 61, hE > 0.96), and Holstein (na = 18, hE > 0.88) populations. BoLA-DRB3*002:01 (14.3 %), BoLA-DRB3*001:01 (8.5 %), and BoLA-DRB3*015:01 (20.2 %) were the most frequent alleles in native, mixed, and Holstein populations, respectively, indicating that the genetic profiles differed in each population. Based on the allele frequencies of BoLA-DRB3, genetic variation among Egyptian, Asian, African, and American breeds was examined using Nei's distances and principal component analysis. The results suggested that native and mixed cattle populations were most closely associated with African breeds in terms of their gene pool, whereas Holstein cattle were more distinct from the other breeds and were closely related to Holstein cattle populations from other countries.

BoLA-DRB3 Polymorphism Associated with Bovine Leukemia Virus Infection and Proviral Load in Holstein Cattle in Egypt

Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, the most prevalent neoplastic disease of cattle worldwide. The immune response to BLV and disease susceptibility and resistance in cattle are strongly correlated with the bovine leukocyte antigen (BoLA)-DRB3 allelic polymorphism. BLV infection continues to spread in Egypt, in part because the relationships between BLV infection, proviral load in Egypt, and BoLA-DRB3 polymorphism are unknown. Here, we identified 18 previously reported alleles in 121 Holstein cows using a polymerase chain reaction sequence-based typing method. Furthermore, BoLA-DRB3 gene polymorphisms in these animals were investigated for their influence on viral infection. BoLA-DRB3*015:01 and BoLA-DRB3*010:01 were identified as susceptible and resistant alleles, respectively, for BLV infection in the tested Holsteins. In addition, BoLA-DRB3*012:01 was associated with low PVL in previous reports but high PVL in Holstein cattle in Egypt. This study is the first to demonstrate that the BoLA-DRB3 polymorphism confers resistance and susceptibility to PVL and infections of BLV in Holstein cattle in Egypt. Our results can be useful for the disease control and eradication of BLV through genetic selection.

TiO2-Photocatalyst-Induced Degradation of Dog and Cat Allergens under Wet and Dry Conditions Causes a Loss in Their Allergenicity

Allergies to dogs and cats can cause enormous damage to human health and the economy. Dog and cat allergens are mainly found in dog and cat dander and are present in small particles in the air and in carpets in homes with dogs and cats. Cleaning houses and washing pets are the main methods for reducing allergens in homes; however, it is difficult to eliminate them completely. Therefore, we aimed to investigate whether a TiO2 photocatalyst could degrade dog and cat allergens. Under wet conditions, exposure to the TiO2 photocatalyst for 24 h degraded Can f1, which is a major dog allergen extracted from dog dander, by 98.3%, and Fel d1, which is a major cat allergen extracted from cat dander, by 93.6-94.4%. Furthermore, under dry conditions, the TiO2 photocatalyst degraded Can f1 and Fel d1 by 92.8% and 59.2-68.4%, respectively. The TiO2 photocatalyst abolished the binding of dog and cat allergens to human IgE by 104.6% and 108.6%, respectively. The results indicated that the TiO2 photocatalyst degraded dog and cat allergens, causing a loss in their allergenicity. Our results suggest that TiO2 photocatalysis can be useful for removing indoor pet allergens and improving the partnership between humans and pets.

Antigenicity of subregions of recombinant bovine leukemia virus (BLV) glycoprotein gp51 for antibody detection

Bovine leukemia virus (BLV) is an enveloped virus, found worldwide that can infect cattle and induce many subclinical symptoms and malignant tumors. BLV infection causes severe economic losses in the cattle industry. The identification of BLV-infected cattle for segregation or elimination would be the most effective way to halt the spread of BLV infection on farms, owing to the lack of effective treatments and vaccines. Therefore, antibody detection against the viral glycoprotein gp51 is an effective method for diagnosing BLV-infected animals. In this study, ten different subregions of gp51 containing a common B cell epitope are vital for developing antigens as epitope-driven vaccine design and immunological assays. Such antigens were produced in Escherichia coli expression system to react with antibodies in the serum from BLV-infected cattle and compete for antigenicity. Recombinant His-gp51^56-110 and gp51^33-301(full) had the same sensitivity in BLV-positive sera, indicating that antibodies responded to the limited subregion of viral gp51, a common B cell epitope. This finding provides significant information for antigen selection in BLV to use in antibody detection assays. Further studies are needed to evaluate the antigenicity of His-gp51^56-110 and gp51^33-301(full) as antigens for antibody detection assays using a larger number of bovine serum samples.

Comparison of the inactivation capacity of various UV wavelengths on SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a worldwide pandemic. Ultraviolet (UV) is regarded as a very powerful tool against SARS-CoV-2. However, the inactivating effects of different UV wavelengths on SARS-CoV-2 under the same conditions have hardly been compared. Here, we showed that SARS-CoV-2 cultured in Dulbecco's modified Eagle's medium and 2% fetal bovine serum was efficiently inactivated by irradiation with 222, 254, and 265 wavelengths UV, but not at 308 nm. In addition, it was revealed that UV absorption by DMEM-2% FBS is very efficient at 222 nm. Our results present potentially important information for selecting the optimum UV wavelength according to the application.

Anti-BLV antibodies in whey correlate with bovine leukemia virus disease progression and BoLA-DRB3 polymorphism

Introduction

Bovine leukemia virus (BLV) belongs to the family Retroviridae and is a causative agent for enzootic bovine leucosis, the most common neoplastic disease affecting cattle worldwide. BLV proviral load (PVL) is associated with disease progression and transmission risk but requires blood collection and quantitative PCR testing. Anti-BLV antibodies in whey have been used as a diagnostic tool for BLV infection; however, quantitative utilization has not been fully investigated. Furthermore, bovine leukocyte antigen (BoLA)-DRB3 is a polymorphic gene associated with BLV infectivity and PVL, but its effect on anti-BLV antibody levels in whey from BLV infected dams is unknown. Therefore, we aimed to investigate whether it is possible to correctly predict PVL in the blood and milk based on the amount of anti-BLV antibodies in milk, and whether the BoLA-DRB3 alleles associate with the amount of anti-BLV antibodies in milk.

Methods

We examined whey from 442 dams from 11 different dairy farms located in 6 prefectures in Japan, including susceptible dams carrying at least one BoLA-DRB3^* 012:01 or ^* 015:01 allele related with high PVL, resistant dams carrying at least one BoLA-DRB3 ^* 002:01, ^* 009:02, or ^* 014:01:01 allele related with low PVL, and neutral dams carrying other alleles.

Results

First, our results provided compelling evidence that anti-BLV antibody levels in whey were positively correlated with the anti-BLV antibody levels in serum and with BLV PVL in blood and milk, indicating the possibility of estimating BLV PVL in blood and milk by measuring anti-BLV antibody levels in whey. Thus, our results showed that antibody titers in milk might be effective for estimating BLV transmission risk and disease progression in the field. Second, we demonstrated that anti-BLV antibody levels in whey from BLV resistant dams were significantly lower than those from susceptible and neutral dams.

Discussion

This is the first report suggesting that the BoLA-DRB3 polymorphism affects anti-BLV antibody levels in whey from BLV-infected dams. Taken together, our results suggested that anti-BLV antibody levels in whey, measured by enzyme-linked immunosorbent assay, may be a useful marker to diagnose the risk of BLV infection and estimate PVL in blood and milk.

Epigallocatechin Gallate Stabilized by Cyclodextrin Inactivates Influenza Virus and Human Coronavirus 229E

Natural products are attractive antiviral agents because they are environment-friendly and mostly harmless. Epigallocatechin gallate (EGCg), a type of catechin, is a well-known natural antiviral agent that can inhibit various viruses. However, EGCg easily oxidizes and loses its physiological activity. Although this problem can be overcome by combining EGCg with cyclodextrin (CD-EGCg), which makes it stable in water at high concentrations, the antiviral effect of this compound remains unclear. Here, we show that in Madin–Darby canine kidney (MDCK) and MRC-5 cells, CD-EGCg is cytotoxic for 50% of cells at 85.61 and 65.34 ppm, respectively. Furthermore, CD-EGCg mainly shows its antiviral effect during the adsorption step for all four influenza virus strains (median effect concentration (EC₅₀) was 0.93 to 2.78 ppm). Its antiviral effect post-adsorption is less intense, and no inhibitory effect is observed on influenza viruses pre-adsorption. Moreover, human coronavirus 229E (HCoV-229E) was inhibited at the adsorption step in short contact (EC₅₀ = 2.5 ppm) and long contact conditions (EC₅₀ = 0.5 ppm) by mixing CD-EGCg with HCoV-229E. These results suggest that CD-EGCg effectively inhibits various viruses that require an adsorption step, and is an effective tool for preventing infection.

WO3 Photocatalyst Containing Copper Inactivates SARS-CoV-2 Pango Lineage A and Omicron BA.2 Variant in Visible Light and in Darkness

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019, which has been a global pandemic. Since SARS-CoV-2 is transmitted through contaminated surfaces and aerosols, environmental disinfection is important to block the spread of the virus. Photocatalysts are attractive tools for virus inactivation and are widely used as air purifiers and coating materials. However, photocatalysts are inactive in the dark, and some of them need to be excited with light of a specific wavelength. Therefore, photocatalysts that can effectively inactivate SARS-CoV-2 in indoor environments are needed. Here, we show that a WO3 photocatalyst containing copper inactivated the SARS-CoV-2 WK-521 strain (Pango lineage A) upon irradiation with white light in a time- and concentration-dependent manner. Additionally, this photocatalyst also inactivated SARS-CoV-2 in dark conditions due to the antiviral effect of copper. Furthermore, this photocatalyst inactivated not only the WK-521 strain but also the Omicron variant BA.2. These results indicate that the WO3 photocatalyst containing copper can inactivate indoor SARS-CoV-2 regardless of the variant, in visible light or darkness, making it an effective tool for controlling the spread of SARS-CoV-2.

A Novel Class of HIV-1 Inhibitors Targeting the Vpr-Induced G2-Arrest in Macrophages by New Yeast- and Cell-Based High-Throughput Screening

The human immunodeficiency virus type 1 (HIV-1) accessory protein, Vpr, arrests the cell cycle of the G2 phase, and this Vpr-mediated G2 arrest is implicated in an efficient HIV-1 spread in monocyte-derived macrophages. Here, we screened new candidates for Vpr-targeting HIV-1 inhibitors by using fission yeast- and mammalian cell-based high-throughput screening. First, fission yeast strains expressing the HIV-1 Vpr protein were generated and then treated for 48 h with 20 μM of a synthetic library, including 140,000 chemical compounds. We identified 268 compounds that recovered the growth of Vpr-overexpressing yeast. The selected compounds were then tested in mammalian cells, and those displaying high cytotoxicity were excluded from further cell cycle analysis and imaging-based screening. A flow cytometry analysis confirmed that seven compounds recovered from the Vpr-induced G2 arrest. The cell toxicity and inhibitory effect of HIV-1 replication in human monocyte-derived macrophages (MDM) were examined, and three independent structural compounds, VTD227, VTD232, and VTD263, were able to inhibit HIV-1 replication in MDM. Furthermore, we showed that VTD227, but not VTD232 and VTD263, can directly bind to Vpr. Our results indicate that three new compounds and their derivatives represent new drugs targeting HIV-1 replication and can be potentially used in clinics to improve the current antiretroviral therapy.

No evidence of bovine leukemia virus proviral DNA and antibodies in human specimens from Japan

Background

The potential risk and association of bovine leukemia virus (BLV) with human remains controversial as it has been reported to be both positive and negative in human breast cancer and blood samples. Therefore, establishing the presence of BLV in comprehensive human clinical samples in different geographical locations is essential.

Result

In this study, we examined the presence of BLV proviral DNA in human blood and breast cancer tissue specimens from Japan. PCR analysis of BLV provirus in 97 Japanese human blood samples and 23 breast cancer tissues showed negative result for all samples tested using long-fragment PCR and highly-sensitive short-fragment PCR amplification. No IgG and IgM antibodies were detected in any of the 97 human serum samples using BLV gp51 and p24 indirect ELISA test. Western blot analysis also showed negative result for IgG and IgM antibodies in all tested human serum samples.

Conclusion

Our results indicate that Japanese human specimens including 97 human blood, 23 breast cancer tissues, and 97 serum samples were negative for BLV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12977-022-00592-6.

Huntingtin-Interacting Protein 1 Promotes Vpr-Induced G2 Arrest and HIV-1 Infection in Macrophages

Human immunodeficiency virus type 1 (HIV-1) modulates the host cell cycle. The HIV-1 accessory protein Vpr arrests the cell cycle at the G2 phase in dividing cells, and the ability of Vpr to induce G2 arrest is well conserved among primate lentiviruses. Additionally, Vpr-mediated G2 arrest likely correlates with enhanced HIV-1 infection in monocyte-derived macrophages. Here, we screened small-interfering RNA to reveal candidates that suppress Vpr-induced G2 arrest and identified Huntingtin-interacting protein 1 (HIP1) required for efficient G2 arrest. Interestingly, HIP1 was not essential for Vpr-induced DNA double-strand breaks, which are required for activation of the DNA-damage checkpoint and G2 arrest. Furthermore, HIP1 knockdown suppressed HIV-1 infection in monocyte-derived macrophages. This study identifies HIP1 as a factor promoting Vpr-induced G2 arrest and HIV-1 infection in macrophages.

UVC disinfects SARS-CoV-2 by induction of viral genome damage without apparent effects on viral morphology and proteins

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a pandemic threat worldwide and causes severe health and economic burdens. Contaminated environments, such as personal items and room surfaces, are considered to have virus transmission potential. Ultraviolet C (UVC) light has demonstrated germicidal ability and removes environmental contamination. UVC has inactivated SARS-CoV-2; however, the underlying mechanisms are not clear. It was confirmed here that UVC 253.7 nm, with a dose of 500 μW/cm2, completely inactivated SARS-CoV-2 in a time-dependent manner and reduced virus infectivity by 10-4.9-fold within 30 s. Immunoblotting analysis for viral spike and nucleocapsid proteins showed that UVC treatment did not damage viral proteins. The viral particle morphology remained intact even when the virus completely lost infectivity after UVC irradiation, as observed by transmission electronic microscopy. In contrast, UVC irradiation-induced genome damage was identified using the newly developed long reverse-transcription quantitative-polymerase chain reaction (RT-qPCR) assay, but not conventional RT-qPCR. The six developed long RT-PCR assays that covered the full-length viral genome clearly indicated a negative correlation between virus infectivity and UVC irradiation-induced genome damage (R2 ranging from 0.75 to 0.96). Altogether, these results provide evidence that UVC inactivates SARS-CoV-2 through the induction of viral genome damage.

SARS-CoV-2 Disinfection of Air and Surface Contamination by TiO2 Photocatalyst-Mediated Damage to Viral Morphology, RNA, and Protein

SARS-CoV-2 is the causative agent of COVID-19, which is a global pandemic. SARS-CoV-2 is transmitted rapidly via contaminated surfaces and aerosols, emphasizing the importance of environmental disinfection to block the spread of virus. Ultraviolet C radiation and chemical compounds are effective for SARS-CoV-2 disinfection, but can only be applied in the absence of humans due to their toxicities. Therefore, development of disinfectants that can be applied in working spaces without evacuating people is needed. Here we showed that TiO2-mediated photocatalytic reaction inactivates SARS-CoV-2 in a time-dependent manner and decreases its infectivity by 99.9% after 20 min and 120 min of treatment in aerosol and liquid, respectively. The mechanistic effects of TiO2 photocatalyst on SARS-CoV-2 virion included decreased total observed virion count, increased virion size, and reduced particle surface spike structure, as determined by transmission electron microscopy. Damage to viral proteins and genome was further confirmed by western blotting and RT-qPCR, respectively. The multi-antiviral effects of TiO2-mediated photocatalytic reaction implies universal disinfection potential for different infectious agents. Notably, TiO2 has no adverse effects on human health, and therefore, TiO2-induced photocatalytic reaction is suitable for disinfection of SARS-CoV-2 and other emerging infectious disease-causing agents in human habitation.

Measurement of axial phase difference of density fluctuations owing to spontaneously excited waves by using microwave reflectometer on GAMMA 10/PDX

In the GAMMA 10/PDX tandem mirror, plasma with strong ion-temperature anisotropy is produced by using the ion cyclotron range of frequency waves. This anisotropy of ion temperature causes several Alfvén-Ion-Cyclotron (AIC) waves to spontaneously excite in the frequency range just below the ion cyclotron frequency. In addition, difference-frequency (DF) waves are excited in the radial inner region of the plasma by wave-wave coupling among the AIC waves. The radial density profiles were measured at multi-axial positions using a frequency-modulation reflectometer with an axial array of microwave antennas, and an axial variation of the density was found to be significant. In addition, a relative phase difference of the DF wave between axially separated two points was first obtained by finely choosing the probing frequency of the reflectometers with a maximum coherence used as a measure, indicating that the DF wave is a propagating wave, while the pump AIC waves are standing waves in the axial region of measurement.

PRMT5 Is Required for Bovine Leukemia Virus Infection In Vivo and Regulates BLV Gene Expression, Syncytium Formation, and Glycosylation In Vitro

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, which is the most common neoplastic disease of cattle and is closely related to human T-cell leukemia viruses. We investigated the role of a new host protein, PRMT5, in BLV infection. We found that PRMT5 is overexpressed only in BLV-infected cattle with a high proviral load, but not in those with a low proviral load. Furthermore, this upregulation continued to the lymphoma stage. PRMT5 expression was upregulated in response to experimental BLV infection; moreover, PRMT5 upregulation began in an early stage of BLV infection rather than after a long period of proviral latency. Second, siRNA-mediated PRMT5 knockdown enhanced BLV gene expression at the transcript and protein levels. Additionally, a selective small-molecule inhibitor of PRMT5 (CMP5) enhanced BLV gene expression. Interestingly, CMP5 treatment, but not siRNA knockdown, altered the gp51 glycosylation pattern and increased the molecular weight of gp51, thereby decreasing BLV-induced syncytium formation. This was supported by the observation that CMP5 treatment enhanced the formation of the complex type of N-glycan more than the high mannose type. In conclusion, PRMT5 overexpression is related to the development of BLV infection with a high proviral load and lymphoma stage and PRMT5 inhibition enhances BLV gene expression. This is the first study to investigate the role of PRMT5 in BLV infection in vivo and in vitro and to reveal a novel function for a small-molecule compound in BLV-gp51 glycosylation processing.

New evidence of bovine leukemia virus circulating in Myanmar cattle through epidemiological and molecular characterization

Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide and causes serious problems for the cattle industry. In this study, we examined the prevalence of BLV infection and the distribution of BLV genotypes in cattle in the northern, central, and southern parts of Myanmar. The prevalence of BLV infection among Myanmar cattle (37.04%) in this study was markedly higher than the prevalence (9.1%) observed in our earlier study in which BLV was detected from the limited number of cattle only from a small area of Myanmar. Phylogenetic analysis of partial env-gp51 sequence of the isolated BLV strains revealed that there are at least three BLV genotypes (genotype-1, genotype-6, and genotype-10) in Myanmar, which have also been detected in the neighboring countries. We performed this study to estimate the BLV proviral load, which is a major diagnosis index for determining the virus transmission risk. The cattle of the three test regions with warm, wet, and humid climatic conditions (upper Sagaing, Yangon, and Kayin) exhibited a high mean proviral load, while cattle of three other regions with low annual rainfall and very high temperature (Mandalay, Magway, and upper Bago) exhibited a low mean proviral load. Further, the level of proviral load and the prevalence of BLV infection in Myanmar native cattle (N = 235) were lower than that in the hybrid cattle (Holstein Friesian × Myanmar native) (N = 62). We also observed that the cattle with high risk for BLV transmission, which have high proviral load, may enhance the BLV infection rate. Hence, to control BLV transmission, it is necessary to eliminate these cattle with high-risk for BLV transmission and to diagnose BLV provirus in cattle in the remaining regions/states of Myanmar sharing a boundary with neighboring countries.

Distinct MCM10 Proteasomal Degradation Profiles by Primate Lentiviruses Vpr Proteins

Viral protein R (Vpr) is an accessory protein found in various primate lentiviruses, including human immunodeficiency viruses type 1 and 2 (HIV-1 and HIV-2) as well as simian immunodeficiency viruses (SIVs). Vpr modulates many processes during viral lifecycle via interaction with several of cellular targets. Previous studies showed that HIV-1 Vpr strengthened degradation of Mini-chromosome Maintenance Protein10 (MCM10) by manipulating DCAF1-Cul4-E3 ligase in proteasome-dependent pathway. However, whether Vpr from other primate lentiviruses are also associated with MCM10 degradation and the ensuing impact remain unknown. Based on phylogenetic analyses, a panel of primate lentiviruses Vpr/x covering main virus lineages was prepared. Distinct MCM10 degradation profiles were mapped and HIV-1, SIVmus and SIVrcm Vprs induced MCM10 degradation in proteasome-dependent pathway. Colocalization and interaction between MCM10 with these Vprs were also observed. Moreover, MCM10 2-7 interaction region was identified as a determinant region susceptible to degradation. However, MCM10 degradation did not alleviate DNA damage response induced by these Vpr proteins. MCM10 degradation by HIV-1 Vpr proteins was correlated with G₂/M arrest, while induction of apoptosis and oligomerization formation of Vpr failed to alter MCM10 proteolysis. The current study demonstrated a distinct interplay pattern between primate lentiviruses Vpr proteins and MCM10.

Three YXXL Sequences of a Bovine Leukemia Virus Transmembrane Protein are Independently Required for Fusion Activity by Controlling Expression on the Cell Membrane

Bovine leukemia virus (BLV), which is closely related to human T-cell leukemia viruses, is the causative agent of enzootic bovine leukosis, the most common neoplastic disease of cattle. The transmembrane subunit of the BLV envelope glycoprotein, gp30, contains three completely conserved YXXL sequences that fit an endocytic sorting motif. The two N-terminal YXXL sequences are reportedly critical for viral infection. However, their actual function in the viral life cycle remains undetermined. Here, we identified the novel roles of each YXXL sequence. Syncytia formation ability was upregulated by a single mutation of the tyrosine (Tyr) residue in any of the three YXXL sequences, indicating that each YXXL sequence is independently able to regulate the fusion event. The alteration resulted from significantly high expression of gp51 on the cell surface, thereby decreasing the amount of gp51 in early endosomes and further revealing that the three YXXL sequences are independently required for internalization of the envelope (Env) protein, following transport to the cell surface. Moreover, the 2nd and 3rd YXXL sequences contributed to Env protein incorporation into the virion by functionally distinct mechanisms. Our findings provide new insights regarding the three YXXL sequences toward the BLV viral life cycle and for developing new anti-BLV drugs.

P5391Systemic administration of high-mobility group box 1 can suppress adverse post-infarction ventricular remodeling in a rat infarction model by enhancing self-regeneration

Background

High-mobility group box 1 protein (HMGB1) reportedly enhances CXCR4-positive bone marrow-derived mesenchymal stem cell (BM-MSC) recruitment to damaged tissue to promote tissue regeneration.

Purpose

Our aim of this study is to evaluate whether systemic administration of HMGB1 might promote tissue repair in a rat myocardial infarction (MI) model.

Methods

We prepared 26 MI model rats with high ligation of the left coronary artery. Two weeks later, HMGB1 (3 mg/kg/day) or phosphate-buffered saline (control: 3 mL/kg/day) was administered for 4 days via femoral vein. Cardiac performance was evaluated by ultrasonography, left ventricular (LV) remodeling via immunostaining. We then used immunostaining to examine MSC recruitment to damaged tissue in green fluorescent protein bone marrow transplantation (GFP-BMT) model rats, and also performed intravital imaging using two-photon microscopy to visualize BM-cells recruitment in real time.

Results

Compared with control rats, there was a significant improvement in the left ventricular ejection fraction of the HMGB1 group (HMGB1 vs. control: 48.6% ± 5.5% vs. 33.6% ± 5.4%; p<0.01) at 4 weeks after each administration. LV remodeling, characterized by interstitial fibrosis, cardiomyocyte hypertrophy, and a decrease of capillary density, was significantly attenuated in the HMGB1 group compared with control rats. On QT-PCR analysis, VEGF mRNA expression was significantly higher in the HMGB1 group than in the control (border zone; 1.6±0.6 vs. 1.1±0.2; p=0.02, septal zone; 1.1±0.1 vs. 0.9±0.1; p<0.01). In GFP-BMT rats, GFP+/PDGFR+ cells were significantly mobilized to the border zone in the HMGB1 group compared with the control (1331±197 vs. 615±45 /mm2; p<0.01), leading to formation of newly developed vasculature (Figure 1). In intravital imaging, more GFP+ cells were mobilized to the infarction area in the HMGB1 group than in the control, which was further enhanced at 12h later. Additionally, SDF-1 expression in the peri-infarction area increased significantly in MI rats compared with normal rats (MI vs. normal; 2.1±0.4 vs. 0.9±0.1; p<0.01), in where some cell-adhesions of vascular endothelial cells were destroyed.

Conclusions

Systemic administration of HMGB1 mobilized BM-MSCs to the damaged myocardium via the SDF-1/CXCR4 signaling complex. Those BM-MSCs might migrate to extracellular matrix in the border zone via the gap of each endothelial cell, leading to induction of angiogenesis and reduced fibrosis.

Acknowledgement/Funding

None

Effects of submaximal cycling at different exercise intensities on maximal isometric force output of the non-exercised elbow flexor muscles

The purpose of this study was to examine the effects of submaximal cycling at different exercise intensities on maximal isometric force output of the non-exercised elbow flexor muscles after the cycling. A total of 8 healthy young men performed multiple maximal voluntary contractions by the right elbow flexion before, immediately after, 5 min after, and 10 min after a 6-min submaximal cycling at ventilatory threshold (LI), 70% [Formula: see text] (MI), and 80% [Formula: see text] (HI) with both arms relaxed in the air. Force and surface electromyogram (EMG) of the right biceps brachii muscle during the multiple MVCs, blood lactate concentration ([La]), cardiorespiratory responses, and sensations of fatigue for legs (SEF-L) were measured before, immediately after, 5 min after, and 10 min after the submaximal cycling with the three different exercise intensities. Immediately after the submaximal cycling, [La], cardiorespiratory responses, and SEF-L were enhanced in proportion to an increase in exercise intensity of the cycling. Changes in force and EMG activity during the multiple MVCs were not significantly different across the three conditions. The findings imply that group III/IV muscle afferent feedback after the submaximal cycling does not determine the magnitude of MVC force loss of the non-exercised upper limb muscles.

A single L288I substitution in the fusion protein of bovine parainfluenza virus type 3 enhances virus growth in semi-suitable cell lines

The bovine parainfluenza virus type 3 BN-CE vaccine strain was obtained by serial passage of the BN-1 strain in chicken embryonic fibroblasts (CEF). We previously identified a substitution (L288I) in the fusion (F) protein between the two strains. To examine the effect of the substitution on CEF adaptation and attenuation, we generated a recombinant BN-1 strain with the L288I substitution in the F protein (F^L288I-EGFP). F^L288I-EGFP replicated more efficiently than a recombinant BN-1 strain (wt-EGFP) in semi-suitable cell lines, suggesting that the L288I substitution was established in the BN-1 strain during the process of adaptation in CEF.

HLA-G1, but Not HLA-G3, Suppresses Human Monocyte/Macrophage-mediated Swine Endothelial Cell Lysis

The inhibitory function of HLA-G1, a class Ib molecule, on monocyte/macrophage-mediated cytotoxicity was examined. The expression of inhibitory receptors that interact with HLA-G, immunoglobulin-like transcript 2 (ILT2), ILT4, and KIR2DL4 (CD158d) on in vitro-generated macrophages obtained from peripheral blood mononuclear cells and the phorbol 12-myristate 13-acetate (PMA)-activated THP-1 cells were examined by flow cytometry. cDNAs of HLA-G1, HLA-G3, HLA-E, and human β2-microglobulin were prepared, transfected into pig endothelial cells (PECs), and macrophage- and the THP-1 cell-mediated PEC cytolysis was then assessed. In vitro-generated macrophages expressed not only ILT2 and ILT4 but CD158d as well. The transgenic HLA-G1 on PEC indicated a significant suppression in macrophage-mediated cytotoxicity, which was equivalent to that of transgenic HLA-E. HLA-G1 was clearly expressed on the cell surface of PEC, whereas the levels of HLA-G3 were much lower and remained in the intracellular space. On the other hand, the PMA-activated THP-1 cell was less expressed these inhibitory molecules than in vitro-generated macrophages. Therefore, the HLA-G1 on PECs showed a significant but relatively smaller suppression to THP-1 cell-mediated cytotoxicity compared to in vitro-generated macrophages. These results indicate that by generating HLA-G1, but not HLA-G3, transgenic pigs can protect porcine grafts from monocyte/macrophage-mediated cytotoxicity.

Studies of Pig Complement: Measurement of Pig CH50, ACH50, and Components

BACKGROUND

On the basis of a comparison of the hemolytic complement titer in pigs with that in humans, the complement system of pigs was investigated. The response of innate immunity, such as the natural antibodies, against humans was also examined.

METHODS

Hemolytic complement activity of pig serum was measured with the use of a microtitration technique. CH50 was determined according to the method of Mayer. ACH50 was assayed according to the methods of Platts-Milles and Ishizaka. Hemolytic activities of C1, C4, C2, C3, C5, C8, and C9 were estimated through the use of intermediate cells and reagents, as described previously. In addition, the pig natural anti-human antibody was studied with the use of human peripheral blood mononuclear cells (PBMCs). Human PBMCs were stained with 5% pig serum, followed by staining with fluorescein isothiocyanate-labeled goat anti-pig IgG and IgM. The resulting stained cells were quantified by use of a FACScalibur system. The alternative pathway of pig complement was also measured with the use of human erythrocytes and normal pooled pig serum with or without Mg(++)EGTA.

RESULTS

Both the CH50 and ACH50 titers were lower than those of humans. Concerning the components, except for C3, each component, that is, C1, C4, C2, C5, C8, and C9, was also lower than that of humans, based on measured values for human complement components. Pig serum clearly contains natural antibodies, IgG and IgM, to human PBMCs. The alternative pathway of pig complement reacted with human erythrocytes.

CONCLUSIONS

As a whole, pig innate immunity, the complement system and natural antibody, recognizes the surfaces of human cells.

Knockout of Cytidine Monophospho-N-Acetylneuraminic Acid (CMP-NeuAc) Hydroxylase From Porcine Endothelial Cells by a CRISPR System

BACKGROUND

We attempted to knock out the expression of Hanganutziu-Deicher (H-D) antigens through the use of a CRISPR (clustered regulatory interspaced short palindromic repeat)/Cas9 system for pig cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH).

METHODS

Plasmids expressing hCas9 and sgRNA for pCMAH were prepared by ligating oligos into the BbsI site of pX330. The N-terminal and C-terminal EGFP coding regions overlapping 482 bp were PCR-amplified and placed under a ubiquitous CAG promoter. The approximately 400-bp genomic fragments containing the sgRNA target sequence of pCMAH were placed into the multi-cloning sites flanked by the EGFP fragments. The pCAG-EGxxFP-target was mixed with pX330 with/without the sgRNA sequences and then introduced into HEK293T cells.

RESULTS

Four oligos and primers, gSO1, gSO3, gSO4, and gSO8, were nominated from 8 candidates. Among them, gSO1 showed the best efficiency. Pig endothelial cells (PECs) from an α-Gal knockout pig were then used to examine the changes in the expression of the H-D antigen by the knockout of the CMAH genome by the pX330-gS01.

CONCLUSIONS

Changes in the expression of the H-D antigen in the PECs with the CRISPR (gS01) were clear in comparison with those in the parental cells, on the basis of FACS analysis data. The expression of the H-D antigen can be knocked out by use of the CRISPR system for pCMAH, thus confirming that this system is a very convenient system for producing knockout pigs.

Supplemental Analysis for N-linked Sugars in Adult Pig Islets

The pig pancreas is considered to be one of the most suitable sources of islets for clinical xenotransplantation. However, after producing α1-3galactosyltransferase knockout pigs, most of the organs of these pigs showed less antigenicity to the human body. Wild-type adult pig islets (APIs) that originally produced negligible levels of α-Gal, different from neonatal porcine islet-like cell clusters, showed a clear antigenicity to human serum. Concerning the so-called non-Gal epitopes, many studies related to glycoproteins and glycolipids are ongoing in efforts to identify them. However, our knowledge of non-Gal glycoantigens remains incomplete. In our previous study, N-glycans were isolated from APIs, and the structures of 28 of the N-glycans were detected. In this study, to identify additional structures, further analyses were performed by liquid chromatography-mass spectrometry (LC-MS). N-glycans were isolated from APIs by the method described by O'Neil et al with minor modifications and LC-MS-based structural analyses were then performed. The detected N-glycan peaks in the LC-MS spectra were selected using the FLexAnalysis software program and the structures of the glycans were predicted using the GlyocoMod Tool. The API preparation contained 11 peaks and 16 structures were then nominated as containing N-linked sugars. Among them, 5 sulfated glycans were estimated, confirming the existence of sulfate structures in N-glycans in API. In addition, these data may supplement several N-glycan structures that contain two deoxyhexose units, such as fucose, to our previous report. The data herein will be helpful for future studies of antigenicity associated with API.

Human HLA-Ev (147) Expression in Transgenic Animals

BACKGROUND

In our previous study, we reported on the development of substituting S147C for HLA-E as a useful gene tool for xenotransplantation. In this study we exchanged the codon of HLA-Ev (147), checked its function, and established a line of transgenic mice.

METHODS

A new construct, a codon exchanging human HLA-Ev (147) + IRES + human beta 2-microgloblin, was established. The construct was subcloned into pCXN2 (the chick beta-actin promoter and cytomegalovirus enhancer) vector. Natural killer cell- and macrophage-mediated cytotoxicities were performed using the established the pig endothelial cell (PEC) line with the new gene. Transgenic mice with it were next produced using a micro-injection method.

RESULTS

The expression of the molecule on PECs was confirmed by the transfection of the plasmid. The established molecules on PECs functioned well in regulating natural killer cell-mediated cytotoxicity and macrophage-mediated cytotoxicity. We have also successfully generated several lines of transgenic mice with this plasmid. The expression of HLA-Ev (147) in each mouse organ was confirmed by assessing the mRNA. The chick beta-actin promoter and cytomegalovirus enhancer resulted in a relatively broad expression of the gene in each organ, and a strong expression in the cases of the heart and lung.

CONCLUSION

A synthetic HLA-Ev (147) gene with a codon usage optimized to a mammalian system represents a critical factor in the development of transgenic animals for xenotransplantation.

Disseminated Metastatic Tissue Calcification After Orthotopic Liver Transplantation: A Case Report

BACKGROUND

Hypercalcemia has been observed in patients after liver transplantation. However, it is rare that the hypercalcemia induced disseminated tissue calcification and heart failure.

CASE REPORT

We report a rare case of heart failure caused by disseminated metastatic tissue calcification that involved extensive progressive myocardial calcification after liver transplantation. A 20-year-old man with end-stage liver disease due to biliary atresia underwent ABO-incompatible living donor liver transplantation. After successful transplantation, he suffered from antibody-mediated rejection. Subsequently, ABO-matched cadaveric liver retransplantation was successfully performed. Hypercalcemia developed gradually following the second transplantation. His serum calcium level increased to 18.3 mg/dL with sudden onset of ventricular tachycardia. Although he was resuscitated with a cardiopulmonary support device, he died of heart and liver failure. Histopathologic examination revealed systemic disseminated metastatic tissue calcification, including massive myocardial calcification.

CONCLUSION

Progressive worsening of hypercalcemia resulted in disseminated metastatic tissue calcification and massive metastatic myocardial calcification, which led to heart failure after liver transplantation. Because hypercalcemia after liver transplantation can cause fatal tissue calcification, early intervention for hypercalcemia should be considered.

Effects of heat exposure in the absence of hyperthermia on power output during repeated cycling sprints

The aim of this study was to investigate the effects of heat exposure in the absence of hyperthermia on power output during repeated cycling sprints. Seven males performed four 10-s cycling sprints interspersed by 30 s of active recovery on a cycle ergometer in hot-dry and thermoneutral environments. Changes in rectal temperature were similar under the two ambient conditions. The mean 2-s power output over the 1st–4th sprints was significantly lower under the hot-dry condition than under the thermoneutral condition. The amplitude of the electromyogram was lower under the hot-dry condition than under the thermoneutral condition during the early phase (0–3 s) of each cycling sprint. No significant difference was observed for blood lactate concentration between the two ambient conditions. Power output at the onset of a cycling sprint during repeated cycling sprints is decreased due to heat exposure in the absence of hyperthermia.

[How to protect the surgeons' faces against spurting blood from the ascending aorta]

The blood spurting from the ascending aorta is uncomfortable for cardiac surgeons. To protect the surgeons' faces from this spurting blood, we use a longitudinal half of a plastic bottle, which is semi see-through. While the assistant is holding this device above the ascending aorta, the surgeons can proceed the operation with good surgical view.

Development of visual cells in the Pacific bluefin tuna Thunnus orientalis

The development of rod and cone photoreceptor cells was investigated in the retinas of Pacific bluefin tuna larvae and juveniles, using RET-P1 monoclonal antibody labeling to identify photoreceptors. At 60 h after hatching, which was about when feeding began, opsin (presumably green opsin (Rh2)) was expressed in the outer segments of cone cells. At 15 days after hatching (dah), although many labeled cone cells were observed in the dorsal retina, the same type of cone cells had partially appeared in the ventral retina. The presence of rod cell bodies was confirmed by the expression of Rh1 opsin at 15 dah. At 21 dah, the presence of outer segments of rod cells was confirmed by the expression of Rh1 opsin and by morphology. The observations suggest that the cone cells were substantially operable upon the development of their outer segment at around the beginning of the post-larval stage, and the rod cells began to function at around 15 to 21 dah, before and during metamorphosis.

Effects of resistive load on performance and surface EMG activity during repeated cycling sprints on a non-isokinetic cycle ergometer

OBJECTIVES

To determine the effects of resistive load on performance and surface electromyogram (SEMG) activity during repeated cycling sprints (RCS) on a non-isokinetic cycle ergometer.

METHODS

Participants performed two RCS tests (ten 10-second cycling sprints) interspersed with both 30- and 360-second recovery periods under light (RCS(L)) and heavy load conditions (RCS(H)) in a random counterbalanced order. Recovery periods of 360 seconds were set before the fifth and ninth sprints.

RESULTS

In the 9th and 10th sprints, the values of peak power output divided by body mass were significantly higher in RCS(H) than in RCS(L). Changes in blood lactate concentration were not different between the two conditions. In RCS(L), the root mean square calculated from the SEMG was significantly lower in the ninth sprint than in the first sprint, but there were no differences between the root mean square in the first sprint and that in the ninth sprint in RCS(H).

CONCLUSIONS

During RCS on a non-isokinetic cycle ergometer, performance and SEMG activity are influenced by resistive load. It is thought that regulation of skeletal muscle recruitment by the central nervous system is associated with fatigue during RCS with a light resistive load.

Effect of change in blood volume in skin plus active muscle on heart rate drift during submaximal exercise

The purpose of the present study was to examine the effect of change in blood volume in skin plus active muscle on heart rate drift during moderate exercise and heavy exercise for 30 min. Total hemoglobin concentration (Total Hb) in the vastus lateralis muscle plus its skin was determined by near-infrared spectroscopy. Total Hb significantly increased and remained stable from 20 min in moderate exercise and from 10 min in heavy exercise. Heart rate (HR) rapidly increased until 3 min and showed a steady state in moderate exercise. HR at 30 min was significantly higher than that at 3 min in moderate exercise. HR rapidly increased until 3 min and then gradually but significantly increased in heavy exercise. Increase in total Hb was not significantly related with HR after 3 min of exercise when HR was around 120 beats per min in moderate exercise. Increase in total Hb was significantly related with HR from 3 min to 10 min in the heavy exercise (correlation coefficients ranged from 0.959 to 0.702). It is concluded that an increase in the blood volume in skin plus active muscle is not simply associated with HR drift.

Effects of sodium bicarbonate ingestion on hyperventilation and recovery of blood pH after a short-term intense exercise

To determine the relationship between hyperventilation and recovery of blood pH during recovery from a heavy exercise, short-term intense exercise (STIE) tests were performed after human subjects ingested 0.3 g.kg(-1) body mass of either NaHCO3 (Alk) or CaCO3 (Pla). Ventilation (VE)-CO2 output (VCO2) slopes during recovery following STIE were significantly lower in Alk than in Pla, indicating that hyperventilation is attenuated under the alkalotic condition. However, this reduction of the slope was the result of unchanged VE and a small increase in VCO2. A significant correlation between VE and blood pH was found during recovery in both conditions. While there was no difference between the VE-pH slopes in the two conditions, VE at the same pH was higher in Alk than in Pla. Furthermore, the values of pH during recovery in both conditions increased toward the preexercise levels of each condition. Thus, although VE-VCO2 slope was decreased under the alkalotic condition, this could not be explained by the ventilatory depression attributed to increase in blood pH. We speculate that hyperventilation after the end of STIE is determined by the VE-pH relationship that was set before STIE or the intensity of the exercise performed.

Relationship between hyperventilation and excessive CO2 output during recovery from repeated cycling sprints

The purpose of the present study was to examine whether excessive CO2 output (VCO2excess) is dominantly attributable to hyperventilation during the period of recovery from repeated cycling sprints. A series of four 10-sec cycling sprints with 30-sec passive recovery periods was performed two times. The first series and second series of cycle sprints (SCS) were followed by 360-sec passive recovery periods (first recovery and second recovery). Increases in blood lactate (DeltaLa) were 11.17+/-2.57 mM from rest to 5.5 min during first recovery and 2.07+/-1.23 mM from the start of the second SCS to 5.5 min during second recovery. CO2 output (VCO2) was significantly higher than O2 uptake (VO2) during both recovery periods. This difference was defined as VCO2excess. VCO2excess was significantly higher during first recovery than during second recovery. VCO2excess was added from rest to the end of first recovery and from the start of the second SCS to the end of second recovery (CO2excess). DeltaLa was significantly related to CO2excess (r=0.845). However, ventilation during first recovery was the same as that during second recovery. End-tidal CO2 pressure (PETCO2) significantly decreased from the resting level during the recovery periods, indicating hyperventilation. PETCO2 during first recovery was significantly higher than that during second recovery. It is concluded that VCO2excess is not simply determined by ventilation during recovery from repeated cycle sprints.

Comparison of oxygen uptake at the onset of decrement-load and constant-load exercise

The purpose of the present study was to examine whether the level of oxygen uptake (V(.)(O2) at the onset of decrement-load exercise (DLE) is lower than that at the onset of constant-load exercise (CLE), since power output, which is the target of V(.)(O2) response, is decreased in DLE. CLE and DLE were performed under the conditions of moderate and heavy exercise intensities. Before and after these main exercises, previous exercise and post exercise were performed at 20 watts. DEL was started at the same power output as that for CLE and power output was decreased at a rate of 15 watts per min. V(.)(O2) in moderate CLE increased at a fast rate and showed a steady state, while V(.)(O2) in moderate DLE increased and decreased linearly. V(.)(O2) at the increasing phase in DLE was at the same level as that in moderate CLE. V(.)(O2) immediately after moderate DLE was higher than that in the previous exercise by 98+/-77.5 ml/min. V(.)(O2) in heavy CLE increased rapidly at first and then slowly increased, while V(.)(O2) in heavy DLE increased rapidly, showing a temporal convexity change, and decreased linearly. V(.)(O2) at the increasing phase of heavy DLE was the same level as that in heavy CLE. V(.)(O2) immediately after heavy DLE was significantly higher than that in the previous exercise by 156+/-131.8 ml/min. Thus, despite the different modes of exercise, V(.)(O2) at the increasing phase in DLE was at the same level as that in CLE due to the effect of the oxygen debt expressed by the higher level of V(.)(O2) at the end of DLE than that in the previous exercise.

Excessive oxygen uptake during exercise and recovery in heavy exercise

The aim of this study was to determine whether excessive oxygen uptake (Vo2) occurs not only during exercise but also during recovery after heavy exercise. After previous exercise at zero watts for 4 min, the main exercise was performed for 10 min. Then recovery exercise at zero watts was performed for 10 min. The main exercises were moderate and heavy exercises at exercise intensities of 40 % and 70 % of peak Vo2, respectively. Vo2 kinetics above zero watts was obtained by subtracting Vo2 at zero watts of previous exercise (DeltaVo2). Delta Vo2 in moderate exercise was multiplied by the ratio of power output performed in moderate and heavy exercises so as to estimate the Delta Vo2 applicable to heavy exercise. The difference between Delta Vo2 in heavy exercise and Delta Vo2 estimated from the value of moderate exercise was obtained. The obtained Vo2 was defined as excessive Vo2. The time constant of excessive Vo2 during exercise (1.88+/-0.70 min) was significantly shorter than that during recovery (9.61+/-6.92 min). Thus, there was excessive Vo2 during recovery from heavy exercise, suggesting that O2/ATP ratio becomes high after a time delay in heavy exercise and the high ratio continues until recovery.

Detection of Escherichia coli O157: H7 vt and rfb(O157) by multiplex polymerase chain reaction

A rapid method for detection of Escherichia coli O157: H7 using multiplex PCR was developed. Two oligonucleotide primer pairs were used for simultaneously detection of vt encoding verotoxin genes for virulence factor and rfb(O157) encoding the O-antigen specific for E. coli O157: H7. Multiplex PCR generated two products of 215 bp and 420 bp for vt and rfb(O157), respectively. Multiplex PCR detected reference strain O157: H7 (NF-7777) with a sensitivity of 10(5) CFU per ml with no amplification of other 15 pathogenic bacteria. After incubation of 10(2) CFU/25 gram raw meat in tryptic soy broth at 37 degrees C for 8 hours, multiplex PCR conducted with the addition of 100 mg bovine serum albumin produced the two specific PCR products for E. coli O157: H7. This modified multiplex PCR is a rapid, sensitive, and specific technique for detecting and differentiating E. coli O157: H7 and has the potential to be used as an alternative to conventional methods for the screening of O157: H7 strains isolated from raw meat.