Engineering of stable infectious cDNA constructs of a fluorescently tagged tomato chlorosis virus

Tomato chlorosis virus (ToCV) is an emerging pathogen that cause severe yellow leaf disorder syndrome in tomato plants. In this study, we aimed to generate a recombinant ToCV tagged with green fluorescent protein (GFP) to enable real-time monitoring of viral infection in living plants. Transformation of the full-length cDNA construct of ToCV RNA1 into Escherichia coli resulted in instability issues, which were successfully overcome by inserting a plant intron into RNA1. Subsequently, a GFP tag was engineered into a cDNA construct of ToCV RNA2. The resulting recombinant ToCV-GFP could systemically infect Nicotiana benthamiana plants, and GFP expression was observed along the major veins. Utilizing ToCV-GFP, we also showed that ToCV engages in antagonistic relationships with two different tomato-infecting viruses in mixed infections in N. benthamiana. This study demonstrates the potential of ToCV-GFP as a valuable tool for the visual tracking of infection and movement of criniviruses in living plants.

The VP53 protein encoded by RNA2 of a fabavirus, broad bean wilt virus 2, is essential for viral systemic infection

Plant viruses evolves diverse strategies to overcome the limitations of their genomic capacity and express multiple proteins, despite the constraints imposed by the host translation system. Broad bean wilt virus 2 (BBWV2) is a widespread viral pathogen, causing severe damage to economically important crops. It is hypothesized that BBWV2 RNA2 possesses two alternative in-frame translation initiation codons, resulting in the production of two largely overlapping proteins, VP53 and VP37. In this study, we aim to investigate the expression and function of VP53, an N-terminally 128-amino-acid-extended form of the viral movement protein VP37, during BBWV2 infection. By engineering various recombinant and mutant constructs of BBWV2 RNA2, here we demonstrate that VP53 is indeed expressed during BBWV2 infection. We also provide evidence of the translation of the two overlapping proteins through ribosomal leaky scanning. Furthermore, our study highlights the indispensability of VP53 for successful systemic infection of BBWV2, as its removal results in the loss of virus infectivity. These insights into the translation mechanism and functional role of VP53 during BBWV2 infection significantly contribute to our understanding of the infection mechanisms employed by fabaviruses.

Visual tracking of viral infection dynamics reveals the synergistic interactions between cucumber mosaic virus and broad bean wilt virus 2

Cucumber mosaic virus (CMV) is one of the most prevalent plant viruses in the world, and causes severe damage to various crops. CMV has been studied as a model RNA virus to better understand viral replication, gene functions, evolution, virion structure, and pathogenicity. However, CMV infection and movement dynamics remain unexplored due to the lack of a stable recombinant virus tagged with a reporter gene. In this study, we generated a CMV infectious cDNA construct tagged with a variant of the flavin-binding LOV photoreceptor (iLOV). The iLOV gene was stably maintained in the CMV genome after more than four weeks of three serial passages between plants. Using the iLOV-tagged recombinant CMV, we visualized CMV infection and movement dynamics in living plants in a time course manner. We also examined whether CMV infection dynamics is influenced by co-infection with broad bean wilt virus 2 (BBWV2). Our results revealed that no spatial interference occurred between CMV and BBWV2. Specifically, BBWV2 facilitated the cell-to-cell movement of CMV in the upper young leaves. In addition, the BBWV2 accumulation level increased after co-infection with CMV.

Differential effects of sex on tuberculosis location and severity across the lifespan

Disparities exist between sexes regarding tuberculosis (TB) incidence, as well as disease severity and outcome. Using a nationwide TB registry database, we explored the impact of sex and age on extrapulmonary TB (EPTB) among all enrolled patients by (1) calculating the female proportion for every age category according to TB-affected locations, (2) calculating the proportions of EPTB stratified by sex according to age, (3) conducting multivariable analysis to examine the impact of sex and age on EPTB likelihood, and (4) assessing the odds of EPTB for female compared to male as reference in every age category. Further, we explored the impact of sex and age on disease severity among pulmonary TB (PTB) patients. Of all the TB patients, 40.1% were female, with a male-to-female ratio of 1.49. The proportion of females was lowest in their fifties, resembling a U-shape. The male-to-female ratios in PTB and EPTB were 1.67 and 1.03, respectively. Compared to men, women were significantly associated with EPTB in their forties, fifties, and sixties. Female patients with PTB had significantly lower odds of having cavitation and positive smear test results in their fifties. Significant differences were found concerning TB location and severity between sexes, especially during reproductive age.

First report of citrus leaf blotch virus infecting Viburnum lentago in South Korea

Viburnum lentago (family Adoxaceae) is a perennial plant species native to northeastern United States and southern Canada. Globally, V. lentago is a popular garden plant due to its abundant flowers and beautiful autumnal color. V. lentago is also commercially cultivated for medicinal purposes because its roots and fruits can be used in herbal preparations (Jiao et al. 2021). In June 2022, virus-like symptoms of vein chlorosis and yellowing were observed in the leaves of many V. lentago trees planted in a public park in Wonju, South Korea. Leaf samples were collected from five symptomatic V. lentago trees. To identify the causal agent(s) of the virus-like symptoms, total RNA was isolated from one sample using PureLink® RNA Mini Kit (Invitrogen, USA) and subjected to library construction using Illumina TruSeq RNA Sample Preparation Kit v2 (Illumina, Inc., USA). RNA-Seq was performed using an Illumina NovaSeq 6000 system (Macrogen, Korea). De novo assembly of 118,878,556 quality-filtered reads was performed using the Trinity pipeline (Kwon et al. 2018), yielding 296,109 contigs. BLASTn and BLASTx analyses of the contigs against the GenBank viral reference database identified only one large contig (8,816 nt) containing a 26-nt poly(A) tail of viral origin. This contig had a maximum nucleotide identity of 85.53 % (with 99 % coverage) with isolate HZ (accession No. MH427034) of citrus leaf blotch virus (CLBV; genus Citrivirus, family Betaflexiviridae), suggesting that the collected sample was infected with CLBV. All collected V. lentago samples were tested using RT-PCR with CLBV-specific primers (CLBV-Det-Fw 5'-AACGAGGCCAATTCTGCTAT-3' and CLBV-Det-Rv 5'-GACTGCTTGACTAACAC-CCA-3'). All samples were positive for CLBV. For biological indexing, sap from the symptomatic V. lentago leaves was mechanically inoculated to indicator plants, including Nicotiana benthamiana, N. occidentalis, N. tabacum, Datura stramonium, Chenopodium quinoa, Vigna unguiculata, and V. lentago. Three months later, only V. lentago developed the same vein chlorosis symptoms observed in the collected samples, and no other tested plants exhibited obvious symptoms. Further, only V. lentago sample tested positive for CLBV using RT-PCR analysis. To determine the complete genome sequence of the CLBV V. lentago isolate, the contig sequence was confirmed by de novo sequencing of the RT-PCR products amplified using CLBV-specific primers. The 5' terminal sequence of the contig was determined using the 5' rapid amplification of cDNA ends method (Seo et al. 2015). The full-length sequence of CLBV isolated from V. lentago was 8,795 nt in length (excluding poly(A) tail), and deposited in GenBank under the accession number OP751940. Although numerous isolates of CLBV have been identified in various plant species, including citrus, kiwi, and lemon plants (Cao et al. 2017), the V. lentago isolate is likely a distinct variant because its CP gene has a maximum nucleotide identity of 85.53 % with that of a kiwi isolate (MH339916). With little information available on viral diseases infecting V. lentago, this is the first identified and completely sequenced CLBV infecting V. lentago. Significantly, V. lentago plants infected with CLBV did not flower throughout the summer period, reducing their value as an ornamental plant. Furthermore, V. lentago might have acted as an intermediate host to transfer CLBV to other crops such as citrus. To the best of our knowledge, this is the first report of CLBV infecting V. lentago in South Korea and the world.

Acute kidney injury due to intravenous detergent poisoning: A case report

BACKGROUND

Detergent poisoning mostly occurs through oral ingestion (> 85%), ocular exposure (< 15%), or dermal exposure (< 8%). Reports of detergent poisoning through an intravenous injection are extremely rare. In addition, there are very few cases of renal toxicity directly caused by detergents. Here, we report a unique case of acute kidney injury caused by detergent poisoning through an accidental intravenous injection.

CASE SUMMARY

A 61-year-old man was intravenously injected with 20 mL of detergent by another patient in the same room of a local hospital. The surfactant and calcium carbonate accounted for the largest proportion of the detergent. The patient complained of vascular pain, chest discomfort, and nausea, and was transferred to our institution. After hospitalization, the patient’s serum creatinine level increased to 5.42 mg/dL, and his daily urine output decreased to approximately 300 mL. Renal biopsy findings noted that the glomeruli were relatively intact; however, diffuse acute tubular injury was observed. Generalized edema was also noted, and the patient underwent a total of four hemodiafiltration sessions. Afterward, the patient’s urine output gradually increased whereas the serum creatinine level decreased. The patient was discharged in a stable status without any sequelae.

CONCLUSION

Detergents appear to directly cause renal tubular injury by systemic absorption. In treating a patient with detergent poisoning, physicians should be aware that the renal function may also deteriorate. In addition, timely renal replacement therapy may help improve the patient’s prognosis.

A multiplex RT-PCR assay for detection of emergent pepper Tsw resistance-breaking variants of tomato spotted wilt virus in South Korea

Tomato spotted wilt virus (TSWV) is a highly destructive virus for pepper. Introgression of the resistance gene Tsw in pepper is used to manage TSWV worldwide; however, the occurrence of Tsw resistance-breaking (RB) variants threatens the pepper industry. Here, we developed a multiplex reverse-transcription PCR assay for detection of recently emerged Tsw RB variants in South Korea with high specificity and sensitivity.

Ethylene emitted by viral pathogen-infected pepper (Capsicum annuum L.) plants is a volatile chemical cue that attracts aphid vectors

Plant viruses are obligate intracellular pathogens, and most depend on insect vectors for transmission between plants. Viral infection causes various physiological and metabolic changes in host traits, which subsequently influence the behavior and fitness of the insect vectors. Cucumber mosaic virus (CMV), one of the most widespread pathogens in pepper (Capsicum annuum L.), is transmitted by aphid vectors in a non-persistent manner. Here, we examined whether CMV infection in pepper affects the behavior of aphid vectors (Myzus persicae and Aphis glycines) in pepper. Aphid preference test revealed that significantly more aphids were attracted to CMV-infected pepper plants than to healthy plants. Comparative transcriptome analysis revealed a significant activation of the ethylene biosynthesis pathway in CMV-infected pepper plants. Indeed, gas chromatography analysis demonstrated that ethylene emission was significantly increased by CMV infection in pepper plants. Elevated ethylene emission in ethephon-treated healthy pepper increased their attractiveness to aphids. In contrast, aphid preference decreased after chemical inhibition of ethylene biosynthesis in CMV-infected pepper plants. Our results suggest that the ethylene emitted by CMV infection is a volatile cue that regulates the attractiveness of pepper plants to M. persicae and A. glycines.

A one-step reverse-transcription loop-mediated isothermal amplification assay optimized for the direct detection of cucumber green mottle mosaic virus in cucurbit seeds

Cucumber green mottle mosaic virus (CGMMV) is a seed-borne virus that causes significant economic losses in farms cultivating cucurbit plants. With the increase in global trade of cucurbit seeds, it is essential to develop a rapid, reliable, and convenient diagnostic method for the direct detection of CGMMV in these seeds for prevention and management of the disease. Here, we developed a one-step reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay for the direct detection of CGMMV in cucurbit seeds. To improve the efficiency of the one-step RT-LAMP assay, six primers were designed to target the most conserved regions of the gene encoding the movement protein of CGMMV. Our one-step RT-LAMP assay was optimized to improve specificity and sensitivity for CGMMV detection in individual seeds. A comparison of the detection sensitivity revealed that our one-step RT-LAMP assay was 100-fold more sensitive than the current reverse transcription-polymerase chain reaction assay used for CGMMV quarantine in Korea. Collectively, the one-step RT-LAMP assay developed in the present study is appropriate for the direct detection of CGMMV in individual cucurbit seeds.

Resistance-Breaking Tomato Spotted Wilt Virus Variant that Recently Occurred in Pepper in South Korea is a Genetic Reassortant

Tomato spotted wilt virus (TSWV) is a destructive viral pathogen in various crops, including pepper. Although the single dominant gene Tsw has been utilized in pepper breeding to confer resistance to TSWV, the occurrence of TSWV variants that overcome Tsw-mediated resistance has been reported in various countries after several years of growing resistant cultivars. In this study, we determined the complete genome sequence of a resistance-breaking TSWV variant (TSWV-YI) that recently emerged in pepper in South Korea. TSWV-YI infected all of the resistant pepper cultivars tested. The phylogenetic and recombination analyses of the complete TSWV-YI genome sequence showed that it is a reassortant that acquired its L and M RNA segments from the existing South Korean TSWV population and its S RNA in an isolate from another country. Given that TSWV-YI is a resistance-breaking variant, it appears that reassortment of the S RNA led to the emergence of this variant that breaks the Tsw gene in pepper grown in South Korea. Our results suggest that resistance-breaking TSWV variants are a potential threat to pepper production in South Korea and that strategies to manage these variants should be developed to ensure sustainable pepper production.

Genetic plasticity in RNA2 is associated with pathogenic diversification of broad bean wilt virus 2

Broad bean wilt virus 2 (BBWV2) is an evolutionarily successful RNA virus with an extensive host range and worldwide distribution that causes severe damage to crops. While numerous BBWV2 isolates from various plant species have been identified and their genome sequences determined, little information is available on the virulence and symptomatic characteristics corresponding to the genomic sequences. In this study, we provide integrated information on the molecular and pathogenic characteristics of three genetically distant BBWV2 isolates: BBWV2-PC, -LS2, and P3 obtained from Gentiana scabra, Leonurus sibiricus, and Pisum sativum, respectively. Phylogenetic and diversity analyses of the BBWV2 population included 42 isolates from various host species and revealed that RNA2 has higher genetic plasticity than RNA1 and may have evolved under host-imposed constraints. In addition, we generated an infectious cDNA clone of BBWV2-PC RNA2 (pBBWV2-PC-R2). Pseudo-recombination analysis of pBBWV2-PC-R2 further demonstrated that RNA2 determines the pathogenic characteristics of the PC isolate.

Complete Nucleotide Sequence, Genome Organization, and Comparative Genomic Analyses of Citrus Yellow-Vein Associated Virus (CYVaV)

Citrus yellow-vein disease (CYVD) was first reported in California in 1957. We now report that CYVD is associated with a virus-like agent, provisionally named citrus yellow-vein associated virus (CYVaV). The CYVaV RNA genome has 2,692 nucleotides and codes for two discernable open reading frames (ORFs). ORF1 encodes a protein of 190 amino acid (aa) whereas ORF2 is presumably generated by a −1 ribosomal frameshifting event just upstream of the ORF1 termination signal. The frameshift product (717 aa) encodes the RNA-dependent RNA polymerase (RdRp). Phylogenetic analyses suggest that CYVaV is closely related to unclassified virus-like RNAs in the family Tombusviridae. Bio-indexing and RNA-seq experiments indicate that CYVaV can induce yellow vein symptoms independently of known citrus viruses or viroids.

Viral Strain-Specific Activation of Pathogen-Associated Molecular Pattern-Triggered Immunity Enhances Symptom Severity in Broad Bean Wilt Virus 2 Infection

Broad bean wilt virus 2 (BBWV2) is an emerging virus in various economically important crops, especially pepper (Capsicum annuum L.), worldwide. Recently, the emergence of various BBWV2 strains that induce severe symptoms has increased damage to pepper crops. While the symptomatic variations among virus strains should be associated with differences in the transcriptomic reprogramming of host plants upon infection, underlying molecular mechanisms and associated genes are largely unknown. In the present study, we employed transcriptome analysis to identify responsible host factors for symptom enhancement in the BBWV2-pepper pathosystem using two distinct BBWV2 strains, PAP1 (a severe strain) and RP1 (a mild strain). Comparative analysis of the differentially expressed genes (DEGs) revealed that various genes associated with pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and ethylene signaling were significantly upregulated upon infection with the severe PAP1 strain, but not with the mild RP1 strain. Indeed, hormone analysis revealed that ethylene emission was significantly increased in pepper plants infected with PAP1. These observations imply that the activation of the PTI-associated defense responses reinforce symptom formation during BBWV2 infection in a virus strain-specific manner.

M1 macrophage dependent-p53 regulates the intracellular survival of mycobacteria

Tumor suppressor p53 is not only affects immune responses but also contributes to antibacterial activity. However, its bactericidal function during mycobacterial infection remains unclear. In this study, we found that the p53-deficient macrophages failed to control Mycobacterium tuberculosis (Mtb), manifested as a lower apoptotic cell death rate and enhanced intracellular survival. The expression levels of p53 during Mtb infection were stronger in M1 macrophages than in M2 macrophages. The TLR2/JNK signaling pathway plays an essential role in the modulation of M1 macrophage polarization upon Mtb infection. It facilitates p53-mediated apoptosis through the production of reactive oxygen species, nitric oxide and inflammatory cytokines in Mtb-infected M1 macrophages. In addition, nutlin-3 effectively abrogated the intracellular survival of mycobacteria in both TB patients and healthy controls after H37Ra infection for 24 h, indicating that the enhancement of p53 production effectively suppressed the intracellular survival of Mtb in hosts. These results suggest that p53 can be a new therapeutic target for TB therapy.

Newly emerged resistance-breaking variants of cucumber mosaic virus represent ongoing host-interactive evolution of an RNA virus

Understanding the evolutionary history of a virus and the mechanisms influencing the direction of its evolution is essential for the development of more durable strategies to control the virus in crop fields. While the deployment of host resistance in crops is the most efficient means to control various viruses, host resistance itself can act as strong selective pressure and thus play a critical role in the evolution of virus virulence. Cucumber mosaic virus (CMV), a plant RNA virus with high evolutionary capacity, has caused endemic disease in various crops worldwide, including pepper (Capsicum annuum L.), because of frequent emergence of resistance-breaking variants. In this study, we examined the molecular and evolutionary characteristics of recently emerged, resistance-breaking CMV variants infecting pepper. Our population genetics analysis revealed that the high divergence capacity of CMV RNA1 might have played an essential role in the host-interactive evolution of CMV and in shaping the CMV population structure in pepper. We also demonstrated that nonsynonymous mutations in RNA1 encoding the 1a protein enabled CMV to overcome the deployed resistance in pepper. Our findings suggest that resistance-driven selective pressures on RNA1 might have contributed in shaping the unique evolutionary pattern of CMV in pepper. Therefore, deployment of a single resistance gene may reduce resistance durability against CMV and more integrated approaches are warranted for successful control of CMV in pepper.

Contents of the Standardized Suicide Prevention Program for Gatekeeper Intervention in Korea, Version 2.0

OBJECTIVE

Suicide is a huge nationwide problem that incurs a lot of socio-economic costs. Suicide also inflicts severe distress on the people left behind. The government of the Republic of Korea has been making many policy efforts to reduce suicide rate. The gatekeeper program, 'Suicide CARE', is one of the meaningful modalities for preventing suicide.

METHODS

Multidisciplinary research team collaborated to update the 'Suicide CARE' to version 2.0.

RESULTS

In the 'Introductory part', the authors have the time to think about the necessity and significance of the program before conducting full-scale gatekeeper training. In the 'Careful observation' part, trainees learn how to understand and recognize the various linguistic, behavioral, and situational signals that a person shows before committing suicide. In the 'Active listening' part, trainees learn how to ask suicide with a value-neutral attitude as well listening empathetically. In the 'Risk evaluation and Expert referral' part, trainees learn intervening strategies to identify a person's suicidal intention, plan, and past suicide attempts, and connect the person to appropriate institutes or services.

CONCLUSION

Subsequent studies should be conducted to verify the efficacy of the gatekeeper program.

"Suicide CARE" (Standardized Suicide Prevention Program for Gatekeeper Intervention in Korea): An Update

OBJECTIVE

In 2011, "Suicide CARE" (Standardized Suicide Prevention Program for Gatekeeper Intervention in Korea) was originally developed for the early detection of warning signs of suicide completion, since there is a tendency to regard emotional suppression as a virtue of Korean traditional culture. A total of 1.2 million individuals completed the training program of "Suicide CARE" in Korea.

METHODS

More sophisticated suicide prevention approaches according to age, sex, and occupation have been proposed, demanding for a more detailed revision of "Suicide CARE." Thus, during the period from August 2019 to February 2020, "Suicide CARE" has been updated to version 2.0. The assessments on domestic gatekeeper training programs for suicide prevention, international gatekeeper training programs for suicide prevention, psychological autopsy interview reports between 2015 and 2018, and the evaluation of feedback from people who completed "Suicide CARE" version 1.6 training were performed.

RESULTS

We describe the revision process of "Suicide CARE," revealing that "Suicide CARE" version 2.0 has been developed using an evidence-based methodology.

CONCLUSION

It is expected that "Suicide CARE" version 2.0 be positioned as the basic framework for many developing gatekeeper training programs for suicide prevention in Korea in the near future.

A Plant Virus-Based Vector System for Gene Function Studies in Pepper

While pepper (Capsicum annuum) is a highly recalcitrant species for genetic transformation studies, plant virus-based vectors can provide alternative and powerful tools for transient regulation and functional analysis of genes of interest in pepper. In this study, we established an effective virus-based vector system applicable for transient gain- and loss-of-function studies in pepper using Broad bean wilt virus2 (BBWV2). We engineered BBWV2 as a dual gene expression vector for simultaneous expression of two recombinant proteins in pepper cells. In addition, we established enhanced and stable expression of recombinant proteins from the BBWV2-based dual vector via coexpression of a heterologous viral suppressor of RNA silencing. We also developed a BBWV2-based virus-induced gene silencing (VIGS) vector, and we successfully silenced the phytoene desaturase gene (PDS) using the BBWV2-based VIGS vector in various pepper cultivars. Additionally, we optimized the BBWV2-based VIGS system in pepper by testing the efficiency of PDS gene silencing under different conditions. This BBWV2-based vector system represents a convenient approach for rapid and simple analysis of gene functions in pepper.

Identification of rehmannia virus 1, a novel putative member of the genus Closterovirus, from Rehmannia glutinosa

Transcriptome sequencing analysis of a symptomatic Rehmannia glutinosa plant revealed a virome containing two known RNA viruses and one novel virus. In this study, we examined the molecular and biological characteristics of the novel virus. The complete genome of the novel virus is composed of monopartite single-stranded RNA of 15,322 nucleotides with 69% nucleotide sequence identity (with 68% coverage) to tobacco virus 1. Its genome organization is typical of the members of the genus Closterovirus, containing nine putative open reading frames. Molecular and phylogenetic analyses of the genome and encoded protein sequences strongly support that the identified virus is a new species of the genus Closterovirus in the family Closteroviridae. The name rehmannia virus 1 (ReV1) is proposed for this novel virus.

Chemical and genetic diversity of high-seed-yield sorghum (Sorghum bicolor M.) germplasms

This study evaluated the chemical and genetic diversity of high-seed-yield sorghum germplasms from Korea, the United States, and South Africa. We identified significant differences in the chemical contents of whole plants at the heading stage in all cultivars, including differences in crude protein, fat, fiber, ash, neutral detergent fiber, acid detergent fiber, mineral, and fatty acid contents. Our results suggest that Banwoldang is the most appropriate cultivar for roughage because of its high protein yield. We identified significant differences in the tannin, flavonoid, amylose, mineral, crude fat, fatty acid, and 3-deoxyanthocyanin contents in the whole grain from all cultivars, but not in the mineral or crude fat contents. Tannin levels were generally low. IS645 contained the highest levels of flavonoids and linolenic acid compounds, and Moktak had the highest amylose and deoxyanthocyanidin content in the grain. To assess genetic diversity, we used 10 simple sequence repeat (SSR) primer sets to identify 38 alleles with 3-8 alleles per locus. Based on phylogenetic analysis of the SSR markers, the sorghum cultivars were divided into three major groups. Comparison of clusters based on chemical compositions with those based on SSRs showed that the groups formed by the three native Korean cultivars clustered similarly in molecular dendrograms. Association analysis was conducted for the 10 SSR marker; 48 chemical and growth traits were present for two marker traits (seed color and whole plant fatty acid content) with significant marker-trait associations. These markers could be used to select sorghum cultivars for breeding programs.

Identification of Leonurus sibiricus as a Weed Reservoir for Three Pepper-Infecting Viruses

In plant virus ecology, weeds are regarded as wild reservoirs of viruses and as potential sources for insect-mediated transmission of viruses. During field surveys in 2013-2014, three Leonurus sibiricus plants showing virus-like symptoms were collected from pepper fields in Daegu, Seosan, and Danyang in Korea. Molecular diagnosis assays showed that the collected L. sibiricus samples were infected with either Tomato spotted wilt virus (TSWV), Pepper mild mottle virus (PMMoV), or Beet western yellow virus (BWYV), respectively. Since this is the first identification of TSWV, PMMoV, and BWYV from L. sibiricus, complete genome sequences of three virus isolates were determined to examine their phylogenetic relationships with the previously reported strains and isolates. Phylogenetic analyses performed using full genome sequences of the viruses showed the isolates of TSWV and PMMoV obtained from L. sibiricus are closely related to the pepper isolates of the corresponding viruses. Our results suggest that L. sibiricus could act an alternative host and reservoir of viruses that cause damages in pepper fields.

Perioperative predictors for refractory hyperglycemia during the neohepatic phase of liver transplantation

BACKGROUND

Hyperglycemia in the neohepatic phase of liver transplantation (LT) tends to decrease toward completion of the surgical procedure. Refractory hyperglycemia in the neohepatic phase (RH) is influenced by multiple perioperative factors and may be connected to posttransplant outcomes. We attempted to demonstrate the relationship of RH to posttransplant outcomes and to establish a predictive model for RH in living donor liver transplantation (LDLT).

METHODS

Perioperative data of 211 patients who underwent LDLT from 2009 and 2012 were reviewed, including declines in the blood glucose levels during the neohepatic phase. Perioperative variables including the posttransplant model for end-stage liver disease (MELD) score until day 30 were compared between patients with normal declines in blood glucose and patients with RH. Selected variables after intergroup comparisons were examined by means of multivariate logistic regression to establish a predictive model for RH occurrence.

RESULTS

The mean blood glucose decline was 22.3 ± 31.5 mg/dL during the neohepatic phase, and 84 of 203 patients (41.4%) had no decline in blood glucose. In intergroup comparisons, preoperative factors associated with RH included sex, Child-Pugh-Turcotte class, MELD score, emergency, liver enzymes, and graft-to-recipient weight ratio. During surgery, surgical time, serum lactate, and arterial pH were associated with RH. After surgery, the RH group showed slower recovery of the MELD score (15.2 versus 11.9 days) and higher MELD scores until day 10 (P < .05). After the multivariate analysis, recipient sex, emergency, surgical time (≤9 h), and the final intraoperative serum lactate level (≥5.0 mmol/L) were included in the predictive model for RH.

CONCLUSIONS

RH was associated with delayed functional recovery of the liver graft in LT. Recipient sex, emergency, surgical time, and the final intraoperative serum lactate level were identified as predictors of RH. Close monitoring of intraoperative blood glucose in LDLT may be an early prognostic indicator.

Type 2C protein phosphatase is a key regulator of antiviral extreme resistance limiting virus spread

Effector-triggered immunity (ETI) is an active immune response triggered by interactions between host resistance proteins and their cognate effectors. Although ETI is often associated with the hypersensitive response (HR), various R genes mediate an HR-independent process known as extreme resistance (ER). In the soybean-Soybean mosaic virus (SMV) pathosystem, the strain-specific CI protein of SMV functions as an effector of Rsv3-mediated ER. In this study, we used the soybean (Rsv3)-SMV (CI) pathosystem to gain insight into the molecular signaling pathway involved in ER. We used genome-wide transcriptome analysis to identify a subset of the type 2C protein phophatase (PP2C) genes that are specifically up-regulated in Rsv3-mediated ER. Gain-of-function analysis of the most significantly expressed soybean PP2C gene, GmPP2C3a, showed that ABA-induced GmPP2C3a functions as a key regulator of Rsv3-mediated ER. Our results further suggest that the primary mechanism of ER against viruses is the inhibition of viral cell-to-cell movement by callose deposition in an ABA signaling-dependent manner.

Effect of an organic buffer layer on the stability of zinc oxide thin-film transistors

Compared with other materials, zinc oxide (ZnO) exhibits stability in air, high-electron mobility, transparency and low light sensitivity. We investigated these properties in ZnO thin-film transistors (TFTs) containing a cross-linked poly(vinyl alcohol) (C-PVA) (1:3) buffer layer stacked between the semiconductor and gate dielectric. We measured the impact of this C-PVA layer on gate bias stress. We measured the transfer characteristics of the saturation region to determine the threshold voltage and the field-effect mobility of the transistors. We recorded a threshold voltage of 11.53 V in the ZnO TFTs with the C-PVA buffer layer, the field-effect mobility was 0.2 cm2/Vs. There was a positive shift in the threshold voltage of deltaV(TH) approximately 10 V in response to the application of a gate bias stress of 20 V. The positive shift in the threshold voltage was lower than that in pristine ZnO TFTs. This finding suggests that the shift in threshold voltage was due to reduced charge trapping at the semiconductor-gate dielectric interface. Our report indicates that the organic buffer layer enhanced the stability of ZnO TFTs.

Repair of the 3' proximal and internal deletions of a satellite RNA associated with Cucumber mosaic virus is directed toward restoring structural integrity

The phenomenon of rapid turnover of 3' proximal nucleotides (nt) lost by the action of nuclease in RNA viruses is integral to replication. Here, a set of six deletions encompassing the 3' 23 nt region of a satellite RNA (satRNA) of Cucumber mosaic virus (CMV) strain Q (Q-sat), were engineered. Repair of the 3' end was not observed in the absence of CMV. However, co-expression with CMV in planta revealed that Q-sat mutants lacking the 3' 18 nt but not the 3' 23 nt are repaired and the progeny accumulation was inversely proportional to the extent of the deletion. Progeny of the 3'Δ3 mutant were repaired to wild type (wt) while those from the remaining four mutants were heterogeneous, exhibiting a wt secondary structure. Analysis of additional 3' internal deletions mutants revealed that progeny with a repaired sequence reminiscent of wt secondary structure were competent for replication and systemic spread.

Past and future of a century old Citrus tristeza virus collection: a California citrus germplasm tale

Citrus tristeza virus (CTV) isolates collected from citrus germplasm, dooryard and field trees in California from 1914 have been maintained in planta under quarantine in the Citrus Clonal Protection Program (CCPP), Riverside, California. This collection, therefore, represents populations of CTV isolates obtained over time and space in California. To determine CTV genetic diversity in this context, genotypes of CTV isolates from the CCPP collection were characterized using multiple molecular markers (MMM). Genotypes T30, VT, and T36 were found at high frequencies with T30 and T30+VT genotypes being the most abundant. The MMM analysis did not identify T3 and B165/T68 genotypes; however, biological and phylogenetic analysis suggested some relationships of CCPP CTV isolates with these two genotypes. Phylogenetic analysis of the CTV coat protein (CP) gene sequences classified the tested isolates into seven distinct clades. Five clades were in association with the standard CTV genotypes T30, T36, T3, VT, and B165/T68. The remaining two identified clades were not related to any standard CTV genotypes. Spatiotemporal analysis indicated a trend of reduced genotype and phylogenetic diversity as well as virulence from southern California (SC) at early (1907-1957) in comparison to that of central California (CC) isolates collected from later (1957-2009) time periods. CTV biological characterization also indicated a reduced number and less virulent stem pitting (SP) CTV isolates compared to seedling yellows isolates introduced to California. This data provides a historical insight of the introduction, movement, and genetic diversity of CTV in California and provides genetic and biological information useful for CTV quarantine, eradication, and disease management strategies such as CTV-SP cross protection.

Functional significance of a hepta nucleotide motif present at the junction of Cucumber mosaic virus satellite RNA multimers in helper-virus dependent replication

Satellite RNAs (satRNA) associated with Cucumber mosaic virus (CMV) have been shown to generate multimers during replication. We have discovered that multimers of a CMV satRNA generated in the absence of its helper virus (HV) are characterized by the addition of a hepta nucleotide motif (HNM) at the monomer junctions. Here, we evaluated the functional significance of HNM in HV-dependent replication by ectopically expressing wild type and mutant forms of satRNA multimers in planta either in (+) or (-)-strand polarity. Comparative replication profiles revealed that (-)-strand multimers with complementary HNM (cHNM) are the preferred initial templates for HV-dependent replication than (-)-strand monomers and multimers lacking the cHNM. Further mutational analyses of the HNM accentuate that preservation of the sequence and native length of HNM is obligatory for efficient replication of satRNA. A model implicating the significance of HNM in HV-dependent production of monomeric and multimeric forms of satRNA is presented.

Molecular dissection of Flock house virus protein B2 reveals that electrostatic interactions between N-terminal domains of B2 monomers are critical for dimerization

Flock house virus (FHV) encodes a suppressor protein B2 to overcome antiviral RNA silencing during infection. Biochemical analyses have shown that a homodimer of B2 binds to double-stranded RNA to inhibit dicer-mediated cleavage of dsRNA and incorporation of small interfering RNAs into the RNA-induced silencing complex. In this study, using FHV-Nicotiana benthamiana system, we identified that the charged amino acids at the N-terminus of B2 are critical for dimerization. Interestingly, B2 mutants defective in dimerization exhibited enhanced silencing suppressor activity, Furthermore, we found that the C-terminal charged amino acids are dispensable for B2 dimerization and viral RNA silencing suppression but are critical for transgene silencing suppression. Additional yeast two hybrid assays revealed that dimerization of B2 is not essential for interacting with the RNA silencing machinery. Taken together, our data provide evidence that both monomeric and dimeric B2 proteins function in different modes to suppress RNA silencing.

Fall detection algorithm for the elderly using acceleration sensors on the shoes

The rate of increase in the number of aging population in Korea is very rapid among OECD-member countries. And fall accident is one of the most common factors that threaten the health of the elderly. Therefore, it is needed to develop a fall detection system for the elderly. Most fall detection systems use accelerometers attached on the torso. And in various studies, it was verified that these systems have high sensitivity and high specificity. However, the elderly would feel uncomfortable when banding a sensor on the chest every day. Therefore, in this study, we attached an accelerometer on the shoes to detect fall in the elderly. This prototype system would be improved as a smaller, low-power system in the next study. Also, applying energy harvesting device to this shoe system is being developed to reduce the weight of battery.

A physical interaction between viral replicase and capsid protein is required for genome-packaging specificity in an RNA virus

Genome packaging is functionally coupled to replication in RNA viruses pathogenic to humans (Poliovirus), insects (Flock house virus [FHV]), and plants (Brome mosaic virus [BMV]). However, the underlying mechanism is not fully understood. We have observed previously that in FHV and BMV, unlike ectopically expressed capsid protein (CP), packaging specificity results from RNA encapsidation by CP that has been translated from mRNA produced from replicating genomic RNA. Consequently, we hypothesize that a physical interaction with replicase increases the CP specificity for packaging viral RNAs. We tested this hypothesis by evaluating the molecular interaction between replicase protein and CP using a FHV-Nicotiana benthamiana system. Bimolecular fluorescence complementation in conjunction with fluorescent cellular protein markers and coimmunoprecipitation assays demonstrated that FHV replicase (protein A) and CP physically interact at the mitochondrial site of replication and that this interaction requires the N-proximal region from either amino acids 1 to 31 or amino acids 32 to 50 of the CP. In contrast to the mitochondrial localization of CP derived from FHV replication, ectopic expression displayed a characteristic punctate pattern on the endoplasmic reticulum (ER). This pattern was altered to relocalize the CP throughout the cytoplasm when the C-proximal hydrophobic domain was deleted. Analysis of the packaging phenotypes of the CP mutants defective either in protein A-CP interactions or ER localization suggested that synchronization between protein A-CP interaction and its subcellular localization is imperative to confer packaging specificity.

Emergence of distinct brome mosaic virus recombinants is determined by the polarity of the inoculum RNA

Despite overwhelming interest in the impact exerted by recombination during evolution of RNA viruses, the relative contribution of the polarity of inoculum templates remains poorly understood. Here, by agroinfiltrating Nicotiana benthamiana leaves, we show that brome mosaic virus (BMV) replicase is competent to initiate positive-strand [(+)-strand] synthesis on an ectopically expressed RNA3 negative strand [(-) strand] and faithfully complete the replication cycle. Consequently, we sought to examine the role of RNA polarity in BMV recombination by expressing a series of replication-defective mutants of BMV RNA3 in (+) or (-) polarity. Temporal analysis of progeny sequences revealed that the genetic makeup of the primary recombinant pool is determined by the polarity of the inoculum template. When the polarity of the inoculum template was (+), the recombinant pool that accumulated during early phases of replication was a mixture of nonhomologous recombinants. These are longer than the inoculum template length, and a nascent 3' untranslated region (UTR) of wild-type (WT) RNA1 or RNA2 was added to the input mutant RNA3 3' UTR due to end-to-end template switching by BMV replicase during (-)-strand synthesis. In contrast, when the polarity of the inoculum was (-), the progeny contained a pool of native-length homologous recombinants generated by template switching of BMV replicase with a nascent UTR from WT RNA1 or RNA2 during (+)-strand synthesis. Repair of a point mutation caused by polymerase error occurred only when the polarity of the inoculum template was (+). These results contribute to the explanation of the functional role of RNA polarity in recombination mediated by copy choice mechanisms.

Quantitative PCR for Etiologic Diagnosis of Methicillin-Resistant Staphylococcus aureus Pneumonia in Intensive Care Unit

Background

Ventilator-associated pneumonia (VAP) requires prompt and appropriate treatment. Since methicillin-resistant Staphylococcus aureus (MRSA) is a frequent pathogen in VAP, rapid identification of it, is pivotal. Our aim was to evaluate the utility of quantitative polymerase chain reaction (qPCR) as a useful method for etiologic diagnoses of MRSA pneumonia.

Methods

We performed qPCR for mecA, S. aureus-specific femA-SA, and S. epidermidis-specific femA-SE genes from bronchoalveolar lavage or bronchial washing samples obtained from clinically-suspected VAP. Molecular identification of MRSA was based on the presence of the mecA and femA-SA gene, with the absence of the femA-SE gene. To compensate for the experimental and clinical conditions, we spiked an internal control in the course of DNA extraction. We estimated number of colony-forming units per mL (CFU/mL) of MRSA samples through a standard curve of a serially-diluted reference MRSA strain. We compared the threshold cycle (Ct) value with the microbiologic results of MRSA.

Results

We obtained the mecA gene standard curve, which showed the detection limit of the mecA gene to be 100 fg, which corresponds to a copy number of 30. We chose cut-off Ct values of 27.94 (equivalent to 1×10⁴ CFU/mL) and 21.78 (equivalent to 1×10⁵ CFU/mL). The sensitivity and specificity of our assay were 88.9% and 88.9% respectively, when compared with quantitative cultures.

Conclusion

Our results were valuable for diagnosing and identifying pathogens involved in VAP. We believe our modified qPCR is an appropriate tool for the rapid diagnosis of clinical pathogens regarding patients in the intensive care unit.

Detection and quantification of viral and satellite RNAs in plant hosts

Northern blotting is a valuable method for detection and quantification of RNA in the field of virology. Although many methods including a various versions of polymerase chain reaction have been developed over the years, Northern blotting has been still considered as a useful and effective method for the analysis of progeny RNA accumulation for viral and subviral pathogens, such as satellite RNAs, in plant hosts. Here, we describe a detailed Northern blot protocol for efficient detection and quantification of viral and satellite RNAs from plant hosts.

Copy number variations of chromosome 17p13.1 might be linked to high risk of lung cancer in heavy smokers

Lung cancer is the most common cause of cancer death worldwide. Smoking is known as the strongest single factor in the development of lung cancer. However, there are inherited genetic factors that cause different responses to cigarette smoking exposure among individuals. We tried to identify these differences in heavy smokers by examining copy number variations (CNVs) between lung cancer patients and healthy controls. Analysis by array comparative genomic hybridization which was tested with 20-person training set (10 lung cancer patients, 10 healthy controls) showed 26 significant (adjusted P < 0.05) clones with either copy number gains or losses. Three genes, KCTD11, FGF11, and PTPRH on chromosomal regions 17p13.1 (KCTD11 and FGF11) and 19q13.42 (PTPRH), were selected (adjusted P < 0.001) and tested by real-time quantitative PCR with 34 healthy controls and 54 lung cancer patients. KCTD11 on the chromosomal region 17p13.1 showed significant high odds ratio (OR = 16.0) in heavy smokers, implying that this is a susceptibility region for lung cancer in this group. Therefore, CNVs of 17p13.1 is a promising candidate to identify individuals with a high genetic risk for the development of lung cancer.

Evidence for alternate states of Cucumber mosaic virus replicase assembly in positive- and negative-strand RNA synthesis

Cucumber mosaic virus (CMV) encodes two viral replication proteins, 1a and 2a. Accumulating evidence implies that different aspects of 1a-2a interaction in replication complex assembly are involved in the regulation of virus replication. To further investigate CMV replicase assembly and to dissect the involvement of replicase activities in negative- and positive-strand synthesis, we transiently expressed CMV RNAs and/or proteins in Nicotiana benthamiana leaves using a DNA or RNA-mediated expression system. Surprisingly, we found that, even in the absence of 1a, 2a is capable of synthesizing positive-strand RNAs, while 1a and 2a are both required for negative-strand synthesis. We also report evidence that 1a capping activities function independently of 2a. Moreover, using 1a mutants, we show that capping activities of 1a are crucial for viral translation but not for RNA transcription. These results support the concept that two or more alternate states of replicase assembly are involved in CMV replication.

Human amnion-derived mesenchymal stem cells are a potential source for uterine stem cell therapy

OBJECTIVES

Human amnion is an easy-to-obtain novel source of human mesenchymal stem cells, which poses little or no ethical dilemmas. We have previously shown that human amnion-derived mesenchymal (HAM) cells exhibit certain mesenchymal stem cell-like characteristics with respect to expression of stem cell markers and differentiation potentials.

MATERIALS AND METHODS

In this study, we further characterized HAM cells' potential for in vivo therapeutic application.

RESULTS

Flow cytometric analyses of HAM cells show that they express several stem cell-related cell surface markers, including CD90, CD105, CD59, CD49d, CD44 and HLA-ABC, but not CD45, CD34, CD31, CD106 or HLA-DR. HAM cells at the 10th passage showed normal karyotype. More interestingly, the AbdB-like HOXA genes HOXA9, HOXA10 and HOXA11 that are expressed in the mesenchyme of the developing female reproductive tract and pregnant uteri are also expressed in HAM cells, suggesting similarities between these two mesenchymal cell types. Progesterone receptor is also highly expressed in HAM cells and expression of genes or proteins in HAM cells could be manipulated with the aid of lentivirus technology or cell-permeable peptides. To test potentials of HAM cells for in vivo application, we introduced enhanced green fluorescence protein (EGFP)-expressing HAM cells to mice by intrauterine infusion (into uteri) or by intravenous injection (into the circulation). Presence of EGFP-expressing cells within the uterine mesenchyme after intrauterine infusion or in lungs after intravenous injection was noted within 1-4 weeks.

CONCLUSIONS

Collectively, these results suggest that HAM cells are a potential source of mesenchymal stem cells with therapeutic potential.

Mutations that alter a repeated ACCA element located at the 5' end of the Potato virus X genome affect RNA accumulation

The repeated ACCA or AC-rich sequence and structural (SL1) elements in the 5' non-translated region (NTR) of the Potato virus X (PVX) RNA play vital roles in the PVX life cycle by controlling translation, RNA replication, movement, and assembly. It has already been shown that the repeated ACCA or AC-rich sequence affect both gRNA and sgRNA accumulation, while not affecting minus-strand RNA accumulation, and are also required for host protein binding. The functional significance of the repeated ACCA sequence elements in the 5' NTR region was investigated by analyzing the effects of deletion and site-directed mutations on PVX replication in Nicotiana benthamiana plants and NT1 protoplasts. Substitution (ACCA into AAAA or UUUU) mutations introduced in the first (nt 10-13) element in the 5' NTR of the PVX RNA significantly affected viral replication, while mutations introduced in the second (nt 17-20) and third (nt 20-23) elements did not. The fourth (nt 29-32) ACCA element weakly affected virus replication, whereas mutations in the fifth (nt 38-41) significantly reduced virus replication due to the structure disruption of SL1 by AAAA and/or UUUU substitutions. Further characterization of the first ACCA element indicated that duplication of ACCA at nt 10-13 (nt 10-17, ACCAACCA) caused severe symptom development as compared to that of wild type, while deletion of the single element (nt 10-13), DeltaACCA) or tripling of this element caused reduced symptom development. Single- and double-nucleotide substitutions introduced into the first ACCA element revealed the importance of CC located at nt positions 11 and 12. Altogether, these results indicate that the first ACCA element is important for PVX replication.

Molecular characterization of a dsRNA mycovirus, Fusarium graminearum virus-DK21, which is phylogenetically related to hypoviruses but has a genome organization and gene expression strategy resembling those of plant potex-like viruses

Fusarium graminearum causes a serious scab disease of small grains in Korea. The nucleotide sequence of the genomic RNA of a double-stranded RNA (dsRNA) virus, Fusarium graminearum virus-DK21 (FgV-DK21), from F. graminearum strain DK21, which is associated with hypovirulence in F. graminearum, was determined and compared to the genome sequences of other mycoviruses, including Cryponectria hypoviruses. The FgV-DK21 dsRNA consists of 6,621 [corrected] nucleotides, excluding the 3'-terminal poly(A) tail. The viral genome has 53- and 46-nucleotide 5' and 3' untranslated regions (UTRs), respectively, and four [corrected] putative open reading frames. A phylogenetic analysis of the deduced amino acid sequence of ORF1, which encodes a putative RNA-dependent RNA polymerase, and those of other mycoviruses revealed that this organism forms a distinct virus clade with other hypoviruses, and is more distantly related to other mycoviruses (3.8 to 24.0% identity). However, pairwise sequence comparisons of the nucleotide and deduced amino acid sequences of ORFs 2 through 4 [corrected] revealed no close relationships to other protein sequences currently available in GenBank. Analyses of RNA accumulation by Northern blot and primer extension indicated that these putative gene products are expressed from at least two different subgenomic RNAs (sgRNAs), in contrast to the cases in other hypoviruses. This study suggests the existence of a new, as yet unassigned, genus of mycoviruses that exhibits a potex-like genome organization and sgRNA accumulation.

The SL1 stem-loop structure at the 5'-end of potato virus X RNA is required for efficient binding to host proteins and for viral infectivity

The 5'-region of Potato virus X (PVX) RNA, which contains an AC-rich, single-stranded region and stem-loop structure 1 (SL1), affects RNA replication and assembly. Using Systemic Evolution of Ligands by EXponential enrichment (SELEX) and the electrophoretic mobility shift assay, we demonstrate that SL1 interacts specifically with tobacco protoplast protein extracts (S100). The 36 nucleotides that correspond to the top region of SL1, which comprises stem C, loop C, stem D, and the tetra loop (TL), were randomized and bound to the S100. Remarkably, the wild-type (wt) sequence was selected in the second round, and the number of wt sequences increased as selection proceeded. All of the selected clones from the fifth round contained the wt sequence. Secondary structure predictions (mFOLD) of the recovered sequences revealed relatively stable stem-loop structures that resembled SL1, although the nucleotide sequences therein were different. Moreover, many of the clones selected in the fourth round conserved the TL and C-C mismatch, which suggests the importance of these elements in host protein binding. The SELEX clone that closely resembled the wt SL1 structure with the TL and C-C mismatch was able to replicate and cause systemic symptoms in plants, while most of the other winners replicated poorly only on inoculated leaves. The RNA replication level on protoplasts was also similarly affected. Taken together, these results indicate that the SL1 of PVX interacts with host protein(s) that play important roles related to virus replication.

cis-Acting sequences required for coat protein binding and in vitro assembly of Potato virus X

The 5' region of Potato virus X (PVX) RNA containing an AC-rich single-stranded region and stem-loop 1 (SL1) has been shown to be important for PVX replication (Miller, E.D., Plante, C.A., Kim, K.-H., Brown, J.W., Hemenway, C., 1998. Stem-loop structure in the 5' region of potato virus X genome required for plus-strand RNA accumulation. J. Mol. Biol. 284, 591-608.). Here, we describe the involvement of SL1 for binding to the PVX coat protein (CP) using an in vitro assembly system and various deletion mutants of the 5' region of PVX RNA. Internal and 5' terminal deletions of the 5'-nontranslated region of PVX RNA were assessed for their effects on formation of assembled virus-like particles (VLPs). Mutant RNAs that contain the top region of SL1 or sequences therein bound to CP to form VLPs. In contrast, transcripts of mutants that disrupt SL1 RNA structure were unable to form VLPs. SELEX was used to further confirm the specific RNA recognition of PVX CP using RNA transcripts containing randomized sequences of the upper portion of SL1. Wild-type (wt) sequences along with many other sequences that resemble SL1 structure were selected after fourth and fifth rounds of SELEX (27.0% and 44.4%, respectively). RNA transcripts from several SELEX winners that are predicted to form stable stem-loop structures very closely resembling wt PVX SL1 VLPs. RNA transcripts not predicted to form secondary structures similar to SL1 did not form VLPs in vitro. Taken together, our results suggest that RNA secondary structural elements within SL1 and/or sequences therein are crucial for formation of VLPs and are required for the specific recognition by the CP subunit.

Cerebral microbleeds are regionally associated with intracerebral hemorrhage

BACKGROUND

Cerebral microbleeds (CMB) may be indicative of a hemorrhage-prone microangiopathy.

OBJECTIVE

To determine if increased numbers of these lesions are predictive of intracerebral hemorrhage (ICH), especially in terms of a distributional association.

METHODS

The authors examined consecutively 227 patients with acute stroke. CMB were counted using T2*-weighted gradient echo MRI data, and old lacunes and leukoaraiosis were also evaluated. The associations between the vascular risk factors and ICH were analyzed. With use of multivariate logistic regression analysis, the locations of the CMB or the old lacunes, which were categorized as being in the corticosubcortical area, the deep gray matter area, or the infratentorial area, were examined with regard to their relationships to the locations of the ICH.

RESULTS

The degrees of the CMB (r = 0.43, p < 0.01) and leukoaraiosis (r = 0.20, p < 0.01) were well correlated with the presence of ICH. Multivariate analysis revealed that the grades of the CMB were associated with the presence of ICH (p < 0.01, odds ratio [OR] = 2.67). CMB in the corticosubcortical area (p < 0.01, OR = 5.50) or deep gray matter (p < 0.01, OR = 2.55) were strongly associated with the presence of ICH in the same area, but no such association was observed in the case of CMB in the infratentorial area or in the case of old lacunes in any area.

CONCLUSIONS

Cerebral microbleeds are strongly associated with the presence of intracerebral hemorrhage, and the distributional associations are also quite strong.

Cellular protein binds to sequences near the 5' terminus of potato virus X RNA that are important for virus replication

The sequences in the 5'-nontranslated region (NTR) of Potato virus X (PVX) genomic RNA were previously reported to contain several regulatory elements that are required for genomic and subgenomic RNA accumulation. To investigate whether cellular proteins bind to these elements, we conducted electrophoretic mobility shift assays (EMSA) with protoplast protein extracts and RNA sequences from the PVX 5'-NTR. These analyses showed that the 5' region of PVX positive-strand RNA formed complexes with cellular proteins. UV cross-linking studies of complexes formed with various deletions of the PVX RNA indicated that a 54-kDa cellular protein (p54) was bound to nt 1-46 at the 5' terminus of PVX RNA. Site-directed mutations introduced within this 46-nt region further indicated that an ACCA sequence element located at nt 10-13 was important for optimal binding. In addition, mutations that decreased the affinity of the template RNA for the cellular factor decreased PVX plus-strand RNA accumulation in protoplasts. These studies suggest that the p54 may function in PVX RNA replication by binding to the 5' terminus of the viral genomic RNA.