Genetic Diversity of the Wild Banana Musa acuminata Colla in Malaysia as Evidenced by AFLP

Musa acuminata Colla (Musaceae), the wild progenitor of thecultivated banana, is highly variable in Malaysia and presentsseveral unresolved nomenclatural problems. AFLP was employedto distinguish among three subspecies of Musa acuminata(subsp.truncata and subsp. malaccensis from peninsular Malaysia andsubsp. microcarpa from Borneo) and to examine whether subsp.truncata is a distinct taxon. Eight primer combinations revealedmolecular markers specific for each of the three taxa. UPGMAcluster analysis showed the three taxa were distinct. Subspeciesmalaccensis which is endemic in peninsular Malaysia and subsp.microcarpa which is endemic in Borneo were found to be moresimilar to each other in their DNA patterns than they are tosubsp. truncata, which is endemic to peninsular Malaysia. Sincesubsp. truncata is genetically separate from subsp. malaccensisand subsp.microcarpa , it cannot be regarded as synonymous witheither of these subspecies. This paper sheds light on the nomenclatureof the three subspecies of Musa acuminata. Copyright 2001 Annalsof Botany Company Musa acuminata Colla, truncata, malaccensis, microcarpa, Musaceae, wild banana, genetic diversity, AFLP, DNA fingerprinting     

Replication of Measles Virus: Distinct Species of Short Nucleocapsids in Cytoplasmic Extracts of Infected Cells

Cytoplasmic extracts of Vero cells infected with wild-strain Edmonston measles virus were found to contain two and probably three distinct species of nucleocapsids. Species sedimenting at 200 and 110S contained RNA which sedimented at 50 and 16 to 18S, respectively. The third nucleocapsid species which sedimented at 170S was not present in all experiments and was not characterized in detail. Essentially all 200 and 170S, as well as a portion of the 110S, nucleocapsids were membrane associated and probably present in part in cell-associated virions. Five of six plaque purified strains derived from wild-type Edmonston virus produced only 200S nucleocapsids. One of these five plaque-purified strains subsequently produced both 200 and 110S nucleocapsids after being passaged by using undiluted inocula. These results suggest that measles virus may produce distinct classes of defective virus containing short nucleocapsids and subgenomic viral RNA.     

Growth and Development of the Banana Plant: II. The Transition from the Vegetative to the Floral Shoot in Musa acuminata cv. Gros Michel

The changes that occur in the shoot apex of the banana, as itpasses from the vegetative to the flowering stage, are described.The crucial events occur well before floral primordia are evident,and they require a redistribution of activity in the variousgrowing regions. The vegetative shoot apex is in a central depressionin the rhizome; there is virtually no internodal growth in theaxis, the most active growth is in the leaf bases; vegetativebuds do not form in the leaf axils but only appear adventitiouslyfar from the tip of the shoot. With the onset of flowering thisis changed; growth in the axis itself, previously suppressed,occurs and flower buds arise as primordia in the axils of subtendingbracts. The bracts do not show the market growth in their baseswhich is so characteristic of leaves. Thus, the shoot apex risesto the level of the rhizome and then above it; as it does so,its tip changes in shape from a broad flattened some to a pointedcone. At the transitional stage, more activity occurs in thecells of the mantle, or tunica, which now consists of 3 to 4layers over the central dome. Below, in the central or mothercell zone of the corpus, which was quiescent in the vegetativeshoot, the cells spring into greater activity, becoming moreprotoplasmic and stain more deeply. Directly below this regionin the rib meristem, cells show transverse divisions. Bractprimordia occur high on the flanks of the apex, and, thoughthey originate in the manner of leaves, their subsequent growthis different. Flower primordia occur even in the axils of bractsclose to the shoot tip. Thus, the problem now is to designatethe source, nature, and mode of action of the stimuli whichinitiate and control this quite different distribution of growthin the floral, as contrasted with the vegetative, shoot. Thesignificance of the previously more quiescent central, or mothercell zone, of the apex as the source of such stimuli, is stressed.Thus, flowering first requires that the limiting controls whichapply to the vegetative shoot be released, and, secondly, thatthe apex of the shoot, rather than the leaf base, becomes themain centre of growth and development.     

Severe Leukopenia and Dysregulated Erythropoiesis in SCID Mice Persistently Infected with the Parvovirus Minute Virus of Mice

Parvovirus minute virus of mice strain i (MVMi) infects committed granulocyte-macrophage CFU and erythroid burst-forming unit (CFU-GM and BFU-E, respectively) and pluripotent (CFU-S) mouse hematopoietic progenitors in vitro. To study the effects of MVMi infection on mouse hemopoiesis in the absence of a specific immune response, adult SCID mice were inoculated by the natural intranasal route of infection and monitored for hematopoietic and viral multiplication parameters. Infected animals developed a very severe viral-dose-dependent leukopenia by 30 days postinfection (d.p.i.) that led to death within 100 days, even though the number of circulating platelets and erythrocytes remained unaltered throughout the disease. In the bone marrow of every lethally inoculated mouse, a deep suppression of CFU-GM and BFU-E clonogenic progenitors occurring during the 20- to 35-d.p.i. interval corresponded with the maximal MVMi production, as determined by the accumulation of virus DNA replicative intermediates and the yield of infectious virus. Viral productive infection was limited to a small subset of primitive cells expressing the major replicative viral antigen (NS-1 protein), the numbers of which declined with the disease. However, the infection induced a sharp and lasting unbalance of the marrow hemopoiesis, denoted by a marked depletion of granulomacrophagic cells (GR-1⁺ and MAC-1⁺) concomitant with a twofold absolute increase in erythroid cells (TER-119⁺). A stimulated definitive erythropoiesis in the infected mice was further evidenced by a 12-fold increase per femur of recognizable proerythroblasts, a quantitative apoptosis confined to uninfected TER-119⁺ cells, as well as by a 4-fold elevation in the number of circulating reticulocytes. Therefore, MVMi targets and suppresses primitive hemopoietic progenitors leading to a very severe leukopenia, but compensatory mechanisms are mounted specifically by the erythroid lineage that maintain an effective erythropoiesis. The results show that infection of SCID mice with the parvovirus MVMi causes a novel dysregulation of murine hemopoiesis in vivo.     

口蹄疫病毒持续感染细胞系的快速选择及其特性研究

采用NH4Cl弱碱法处理感染口蹄疫病毒的叙利亚仓鼠肾细胞系(BHK-21), 存活细胞经过单克隆和选择,获得32株阳性克隆细胞株.随机选取一株(BHK-ROp),常规传代并采用RT-PCR,透射电子显微镜,流式细胞仪进行持续感染特性分析,结果表明,BHK-ROp第4,16,36代细胞中病毒持续存在,但不影响细胞的生长特性,表现出病毒持续感染的基本特征.可见,NH4Cl弱碱法用于建立病毒持续感染细胞系是十分有效的.     

口蹄疫病毒持续感染细胞系的快速选择及其特性研究

采用NH4Cl弱碱法处理感染口蹄疫病毒的叙利亚仓鼠肾细胞系(BHK—21),存活细胞经过单克隆和选择,获得32株阳性克隆细胞株。随机选取一株(BHK—ROp),常规传代并采用RT-PCR,透射电子显微镜,流式细胞仪进行持续感染特性分析,结果表明,BHK—ROp第4,16,36代细胞中病毒持续存在,但不影响细胞的生长特性,表现出病毒持续感染的基本特征。可见,NH4Cl弱碱法用于建立病毒持续感染细胞系是十分有效的。     

Influence of Liquid Pulse Treatment with Growth Regulators on in vitro Propagation of Banana (Musa spp. AAA)

The effect of liquid pulse treatment of growth regulators on in vitro propagation of banana (Musa spp. AAA) was studied. Optimal shoot proliferation rates were achieved due to the pulse treatment of 6-benzylaminopurine (BA) and kinetin combination (1:1) at the concentration of 50 mg l^–1 for 60 min. Similarly high frequency of root induction was obtained due to pulse treatment with a NAA and IBA combination (1:1) at the concentration of 100 mg l^–1 for 60 min.     

Occurrence of Ralstonia solanacearum Race 2 Biovar 1 Associated with Moko Disease of Banana (Musa paradisiaca cv. Nipah) in Malaysia

During June 2011 to March 2012, Moko disease symptoms were observed in banana cv. Nipah in two Malaysian states. The primer pairs ISRso19F/ISRso19R were used for defined identification of Ralstonia solanacearum race 2 strain. PCR amplification of all isolates produced a 1900 amplicon and exhibited 93% phylogenetic similarity with reference strain (AF450275). Based on symptoms, biochemical tests, pathogenicity assay, molecular and phylogenetic studies, we concluded that the isolated bacterium was R. solanacearum race 2 biovar 1.     

Differential Regulation of TLR Signaling on the Induction of Antiviral Interferons in Human Intestinal Epithelial Cells Infected with Enterovirus 71

Enterovirus 71 (EV71) causes hand-foot-and-mouth disease, which can lead to fatal neurological complications in young children and infants. Few gastrointestinal symptoms are observed clinically, suggesting the presence of a unique immunity to EV71 in the gut. We reported a robust induction of interferons (IFNs) in human intestinal epithelial cells (HT-29), which was suppressed in other types such as RD and HeLa cells. The underlying mechanism for the apparent difference remains obscure. In this study we report that in EV71-infected HT-29 cells, TLR/TRIF signaling was essential to IFN induction; viral replication increased and the induction of IFN-α, -β, -ω, -κ, and -ε decreased markedly in TRIF-silenced HT-29 cells. Importantly, TRIF was degraded by viral 3C^pro in RD cells, but resisted cleavage, and IRF3 was activated and translocated into the nucleus in HT-29 cells. Taken together, our data suggest that IFNs were induced differentially in human HT-29 cells through an intact TLR/TRIF signaling, which differs from other cell types and may be implicated in viral pathogenesis in EV71 infection.     

Identification of RNA Binding Proteins Associated with Dengue Virus RNA in Infected Cells Reveals Temporally Distinct Host Factor Requirements

BackgroundThere are currently no vaccines or antivirals available for dengue virus infection, which can cause dengue hemorrhagic fever and death. A better understanding of the host pathogen interaction is required to develop effective therapies to treat DENV. In particular, very little is known about how cellular RNA binding proteins interact with viral RNAs. RNAs within cells are not naked; rather they are coated with proteins that affect localization, stability, translation and (for viruses) replication.Conclusions/SignificanceThe method for identification of host factors described here is robust and broadly applicable to all RNA viruses, providing an avenue to determine the conserved or distinct mechanisms through which diverse viruses manage the viral RNA within cells. This study significantly increases the number of cellular factors known to interact with DENV and reveals how DENV modulates and usurps cellular proteins for efficient amplification.     

Effects of Host Cell Density on Cell Infection Level in Antheraea eucalypti (Lepidoptera: Saturniidae) Cell Cultures Persistently Infected with Nosema bombycis (Microsporida: Nosematidae)

ABSTRACT. Spores of Nosema bombycis Y9101, isolated from the beet armyworm, Spodoptera exigua , were primed with an alkaline solution and inoculated into Antheraea eucalypti cell cultures. Infected cells were subcultured every five days at three cell densities (2.5 × 10³, 5.0 × 10³, and 1.0 × 10⁴ cells/cm²). A difference was observed in the spread of N. bombycis Y9101 infection between low-density and higher-density cultures of host cells. The host cell density did not affect the productivity of secondary infective forms of the parasite. The principal factor determining the rate of microsporidian infection in vitro was the number of host cells existing within the reach of extruded short-coiled polar tubes from spores germinated intracellularly.     

Increasing HIV and Decreasing Syphilis Prevalence in a Context of Persistently High Unprotected Anal Intercourse,Six Consecutive Annual Surveys among Men Who Have Sex with Men in Guangzhou,China, 2008 to 2013

Introduction

Previous studies have reported a possibly increasing HIV prevalence among men who have sex with men (MSM) in China. However there have been limited systematic analyses of existing surveillance data to learn the trend of HIV prevalence and factors driving the trend. The aims of this study were to examine the trend of HIV prevalence among MSM in Guangzhou and to explore the role of unprotected anal intercourse (UAI) in the trend.

Methods

Snow-ball sampling was applied in the subject recruitment for the annual serological and behavioral surveys among MSM from 2008 to 2013. Data collected in the behavioral survey include demographic information, HIV related sexual behavior with men and women, access to HIV prevention services, and symptoms of sexually transmitted infections. Chi-square test was used to analyze the trend of HIV prevalence. Multivariate logistic regression was conducted to test the factors associated with HIV infection.

Results

HIV prevalence increased significantly from 5.0% in 2008 to 11.4% in 2013 while syphilis prevalence decreased from 17.4% to 3.3% in the same period. UAI rates were high and stable in every single year, ranging from 54.5% to 62.0%. Those who were having UAI (OR = 1.80, 95% confidence interval (CI): 1.26–2.58), being migrants, having more than 10 partners, and infected with syphilis had higher risk for HIV infection.

Conclusions

HIV epidemic is expanding in Guangzhou. The persistently high UAI may have played a major role in the increasing trend of HIV prevalence. Targeted prevention program should be conducted among MSM who are migrants, low educational level, syphilis infected, or having multiple partners to encourage HIV test and change UAI behavior. The general high UAI calls for tailored intervention program to promote healthy culture and form a safe sex social norm in the MSM community.     

Validation of Six Short and Ultra-short Screening Instruments for Depression for People Living with HIV in Ontario: Results from the Ontario HIV Treatment Network Cohort Study

Objective

Major depression affects up to half of people living with HIV. However, among HIV-positive patients, depression goes unrecognized 60–70% of the time in non-psychiatric settings. We sought to evaluate three screening instruments and their short forms to facilitate the recognition of current depression in HIV-positive patients attending HIV specialty care clinics in Ontario.

Methods

A multi-centre validation study was conducted in Ontario to examine the validity and accuracy of three instruments (the Center for Epidemiologic Depression Scale [CESD₂₀], the Kessler Psychological Distress Scale [K₁₀], and the Patient Health Questionnaire depression scale [PHQ₉]) and their short forms (CESD₁₀, K₆, and PHQ₂) in diagnosing current major depression among 190 HIV-positive patients in Ontario. Results from the three instruments and their short forms were compared to results from the gold standard measured by Mini International Neuropsychiatric Interview (the “M.I.N.I.”).

Results

Overall, the three instruments identified depression with excellent accuracy and validity (area under the curve [AUC]>0.9) and good reliability (Kappa statistics: 0.71–0.79; Cronbach’s alpha: 0.87–0.93). We did not find that the AUCs differed in instrument pairs (p-value>0.09), or between the instruments and their short forms (p-value>0.3). Except for the PHQ_2, the instruments showed good-to-excellent sensitivity (0.86–1.0) and specificity (0.81–0.87), excellent negative predictive value (>0.90), and moderate positive predictive value (0.49–0.58) at their optimal cut-points.

Conclusion

Among people in HIV care in Ontario, Canada, the three instruments and their short forms performed equally well and accurately. When further in-depth assessments become available, shorter instruments might find greater clinical acceptance. This could lead to clinical benefits in fast-paced speciality HIV care settings and better management of depression in HIV-positive patients.