Boundary spanning and identity work in the clinical research delivery workforce: a qualitative study of research nurses, midwives and allied health professionals in the National Health Service, United Kingdom.

BACKGROUND: Research nurses, midwives and allied health professionals are members of an important emergent profession delivering clinical research and, in the United Kingdom, have been the focus of considerable investment by the National Institute for Health Research (NIHR). This paper considers the experiences of research nurses, midwives and allied health professionals in relation to professional identity work, recognizing these are coproduced alongside others that they interact with (including patients, clinical staff and other research staff). METHODS: Semi-structured interviews were conducted with 45 nurses, midwives and allied health professionals in the UK about their experiences of working in research delivery. Interviews were transcribed verbatim and thematically coded and analysed. RESULTS: Our analysis highlights how research nurses, midwives and allied health professionals adjust to new roles, shift their professional identities and undertake identity work using uniforms, name badges and job titles as they negotiate complex identities. CONCLUSIONS: Research nurses, midwives and allied health professionals experience considerable challenges as they enter and transition to a research delivery role, with implications for their sense of professional identities. A change in the work that they undertake and how they are (or perceive they are) viewed by others (including clinical non-research colleagues and patients) has implications for their sense of professional and individual identity. The tensions involved extend to their views on symbols of professional identity, such as uniforms, and as they seek to articulate and demonstrate the value of their conjoined role in research and as a healthcare professional, within the unfolding landscape of health research. We embed our study findings in the context of the newly emerging clinical research practitioner workforce, which further exacerbates and complicates the role and identity complexity for nurses, midwives and allied health professionals in research delivery.

Neighbourhood influence on the fourth dose of diphtheria-tetanus-pertussis vaccination.

OBJECTIVES: Using 542,159 vaccination records from children born between April 1, 2007, and March 31, 2012, in the Michigan Care Improvement Registry and data from the American Community Survey, we determine if neighbourhood-level characteristics at the Census tract level and block level are associated with low uptake of the fourth dose of diphtheria-tetanus-acellular pertussis vaccine (DTaP4). STUDY DESIGN: This study was a cross-sectional study. METHODS: We used exploratory factor analysis to determine important socio-economic factors at the Census block level and tract level. We then used generalised estimating equations to test the relationship between block- and tract-level socio-economic factors and DTaP4 uptake. RESULTS: DTaP4 coverage was 88.6% (95% confidence interval [CI]: 88.4%-88.7%) in Michigan. At the Census tract level, two factors surfaced as important for DTaP4 vaccination: 'affluence' (Cronbach's alpha = 0.88) and 'socio-economic disadvantage' (Cronbach's alpha = 0.89). At the Census block level, one factor was important: 'affluence' (Cronbach's alpha = 0.90). Affluence may relate to knowledge about medical exemptions and antivaccination sentiment, while socio-economic disadvantage may indicate limited access to healthcare resources. Children in high-affluence tracts had 1.08% lower vaccination coverage (95% CI: -1.62% to -0.55%) than children in low affluence tracts. Children in low socio-economic disadvantage tracts had 2.92% higher coverage than children in high socio-economic disadvantage tracts (95% CI: 2.58%-3.26%). CONCLUSIONS: This study articulates the need to further understand the contribution of neighbourhood-level characteristics, from both affluent and socioeconomically disadvantaged areas to low vaccination rates. Developing a better understanding of these social environmental factors will help determine useful community-level interventions to improve vaccination rates and reduce disease burden.

Factors associated with intentional and unintentional non-adherence to adjuvant endocrine therapy following breast cancer.

Adherence to adjuvant endocrine therapy (AET) following breast cancer is known to be suboptimal despite its known efficacy in reducing recurrence and mortality. This study aims to investigate factors associated with non-adherence and inform the development of interventions to support women and promote adherence. A questionnaire survey to measure level of adherence, side effects experienced, beliefs about medicine, support received and socio-demographic details was sent to 292 women 2-4 years post breast cancer diagnosis. Differences between non-adherers and adherers to AET were explored, and factors associated with intentional and unintentional non-adherence are reported. Approximately one quarter of respondents, 46 (22%), were non-adherers, comprising 29 (14%) intentional non-adherers and 17 (8%) unintentional non-adherers. Factors significantly associated with intentional non-adherence were the presence of side effects (p < .03), greater concerns about AET (p < .001) and a lower perceived necessity to take AET (p < .001). Half of the sample (105/211) reported that side effects had a moderate or high impact on their quality of life. Factors associated with unintentional non-adherence were younger age (<65) (p < .001), post-secondary education (p = .046) and paid employment (p = .031). There are distinct differences between intentional non-adherence and unintentional non-adherence. Differentiation between the two types of non-adherence may help tailor support and advice interventions.

Syndromic surveillance for influenza in Tianjin, China: 2013-14.

Background: Diverse sources of syndromic surveillance including over-the-counter (OTC) drug sales, hospital and school-based influenza-like illness (ILI) and Baidu search queries estimate influenza activity in Tianjin, China. The purpose of this study was to determine which syndromic surveillance systems had the strongest correlation with laboratory-confirmed influenza activity. Methods: Data were obtained from sentinel hospitals and laboratories; sentinel hospitals also reported percentage of ILI. OTC sales and school-based ILI absentee data were provided by public pharmacies and schools. Baidu search queries for influenza surveillance were analyzed. Spearman correlation analysis examined correlations of syndromic systems with laboratory-confirmed data. Results: Syndromic data for hospital ILI%, OTC sales and school-based ILI correlated well with laboratory data (r = 0.732, 0.490 and 0.693, respectively; P < 0.05). Baidu, the predominant Chinese Internet service, searches for 'influenza', 'cough' and 'fever' correlated best with laboratory-confirmed activity; queries for 'fever' were strongest (r = 0.924, P < 0.001). Correlations between school-based ILI and laboratory-confirmed influenza increased from 0.693 to 0.795 after a 1-week lag (P < 0.05). Conclusions: A Baidu query of 'fever' provided the strongest correlation to laboratory surveillance. School-based ILI absence reporting detected influenza virus activity 1 week earlier than laboratory confirmation. Use of diverse syndromic surveillance systems in conjunction with traditional surveillance systems can improve influenza surveillance.

Risk factors for measles among infants in Tianjin, China.

OBJECTIVES: Infants aged <8 months are ineligible for measles vaccination in China but represent a disproportionate number of cases. We examined the risk factors for measles among infants in Tianjin, China. STUDY DESIGN: Case-control study. METHODS: Cases were enrolled from a surveillance system, and IgG-negative controls were sampled from registries at immunization clinics. A logistic regression model assessed for risk factors. RESULTS: Among 82 cases and 485 controls, exposure to a municipal hospital (OR [odds ratio]: 5.21; 95% confidence interval [CI]: 1.19-22.82) or a specialty hospital (OR: 13.22; 95% CI: 6.13-28.51) was associated with the disease, whereas visiting a township or district hospitals was not associated with increased odds of measles. CONCLUSIONS: Hospitals were an important focal point of measles transmission for infants. Hospitals, particularly higher-level municipal and specialty hospitals, should enforce infection control programs to separate infants with highly communicable diseases to prevent transmission.

A qualitative study of cancer survivors' responses to information on the long-term and late effects of pelvic radiotherapy 1-11 years post treatment.

As more patients survive cancer for longer term, the long-term and late effects of treatments become increasingly important issues for cancer survivors and providing information to enable survivors to recognise and manage them becomes an increasingly pressing challenge for health care professionals. The aim of this study was to explore the experiences of cancer survivors regarding information given on potential long-term and late effects of pelvic radiotherapy. Semi-structured interviews were conducted with 28 cancer survivors who had had radiotherapy to the pelvic area for a range of cancers 1-11 years previously. Participants were recruited using maximum variation sampling from a larger questionnaire survey of patients treated at one hospital. Interviews were recorded, transcribed and analysed using Framework. Participants recognised the value of information to reassure and to inform action but also its potentially undesirable effects to frighten or raise anxieties about future problems and its inherent limitations in meeting their wider needs. They identified the timing, amount of information and context in which it was given as of particular importance. Information based on personal experience was also valued. These findings highlight the importance of appropriate, individualised information during treatment, at hospital discharge and subsequently in primary care.

The 'Green Revolution' dwarfing genes play a role in disease resistance in Triticum aestivum and Hordeum vulgare.

The Green Revolution dwarfing genes, Rht-B1b and Rht-D1b, encode mutant forms of DELLA proteins and are present in most modern wheat varieties. DELLA proteins have been implicated in the response to biotic stress in the model plant, Arabidopsis thaliana. Using defined wheat Rht near-isogenic lines and barley Sln1 gain of function (GoF) and loss of function (LoF) lines, the role of DELLA in response to biotic stress was investigated in pathosystems representing contrasting trophic styles (biotrophic, hemibiotrophic, and necrotrophic). GoF mutant alleles in wheat and barley confer a resistance trade-off with increased susceptibility to biotrophic pathogens and increased resistance to necrotrophic pathogens whilst the converse was conferred by a LoF mutant allele. The polyploid nature of the wheat genome buffered the effect of single Rht GoF mutations relative to barley (diploid), particularly in respect of increased susceptibility to biotrophic pathogens. A role for DELLA in controlling cell death responses is proposed. Similar to Arabidopsis, a resistance trade-off to pathogens with contrasting pathogenic lifestyles has been identified in monocotyledonous cereal species. Appreciation of the pleiotropic role of DELLA in biotic stress responses in cereals has implications for plant breeding.

Proteomic profiling of human retinal pigment epithelium exposed to an advanced glycation-modified substrate.

PURPOSE: The retinal pigment epithelium (RPE) and underlying Bruch's membrane undergo significant modulation during ageing. Progressive, age-related modifications of lipids and proteins by advanced glycation end products (AGEs) at this cell-substrate interface have been implicated in RPE dysfunction and the progression to age-related macular degeneration (AMD). The pathogenic nature of these adducts in Bruch's membrane and their influence on the overlying RPE remains unclear. This study aimed to identify alterations in RPE protein expression in cells exposed to AGE-modified basement membrane (AGE-BM), to determine how this "aged" substrate impacts RPE function and to map the localisation of identified proteins in ageing retina. METHODS: Confluent ARPE-19 monolayers were cultured on AGE-BM and native, non-modified BM (BM). Following 28-day incubation, the proteome was profiled using 2-dimensional gel electrophoresis (2D), densitometry and image analysis was employed to map proteins of interest that were identified by electrospray ionisation mass spectrometry (ESI MS/MS). Immunocytochemistry was employed to localise identified proteins in ARPE-19 monolayers cultured on unmodified and AGE-BM and to analyze aged human retina. RESULTS: Image analysis detected altered protein spot densities between treatment groups, and proteins of interest were identified by LC ESI MS/MS which included heat-shock proteins, cytoskeletal and metabolic regulators. Immunocytochemistry revealed deubiquitinating enzyme ubiquitin carboxyterminal hydrolase-1 (UCH-L1), which was upregulated in AGE-exposed RPE and was also localised to RPE in human retinal sections. CONCLUSIONS: This study has demonstrated that AGE-modification of basement membrane alters the RPE proteome. Many proteins are changed in this ageing model, including UCHL-1, which could impact upon RPE degradative capacity. Accumulation of AGEs at Bruch"s membrane could play a significant role in age-related dysfunction of the RPE.

Human rabies in Tianjin, China.

BACKGROUND: Human rabies has recently re-emerged as a significant public health threat in Tianjin, China. METHODS: Using surveillance data compiled by the Tianjin Centers for Disease Control and Prevention, we describe 60 cases of human rabies reported from 2005 to 2011 in the municipality of Tianjin, China. RESULTS: All 60 cases of human rabies resulted in death. Cases were primarily male (80%), middle aged (mean 40.6 years), and exposed to rabies in a rural setting (82%). Most exposures were associated with dog bites (93%) and no animal had a history of rabies vaccination; no cases were laboratory confirmed. Fifteen percent of patients sought medical attention for their wound, and none received a complete regimen of WHO-recommended post-exposure prophylaxis (PEP). CONCLUSIONS: These findings suggest the need for China's public health authority to improve animal rabies surveillance and control strategies through laboratory case confirmation, more rapid response to potential exposures with provision of appropriate PEP, and education to the public and to health care providers on identifying and reducing rabies risk.

An evaluation of immunization services, using the reaching every district criteria, in two districts of Gujarat, India.

BACKGROUND: Immunizations are considered the most successful and cost-effective public health interventions employed today. While immunization coverage in India has improved dramatically in the last decade, areas of very low coverage persist. The University of Michigan School of Public Health and the Indian Institute of Public Health Gandhinagar collaborated to document strengths and weaknesses of immunization service delivery in two districts in India. METHODS: This report describes a qualitative assessment of clinic level immunization service delivery in ten primary health centers (PHCs) located in two districts of Gujarat, India. Assessment criteria were derived from the Reaching Every District (RED) strategy that is intended to provide a framework for delivering childhood immunizations. Staff from the PHCs were interviewed in April 2013. RESULTS: Interviews revealed several barriers to immunization service delivery including: 1) Vaccine and supply stockouts; 2) Hard to reach communities; 3) Unreliable Internet access; 4) Cold chain equipment malfunctions; 5) Inconsistently maintained and utilized immunization records and registries. CONCLUSIONS: Immunization service delivery is a complex process that can encounter barriers at many stages. A RED-based evaluation of the vaccine delivery system in Gujarat, India identified several points where the system was performing sub-optimally and possible solutions to successfully address these challenges.

VEGF-A regulates the expression of VEGF-C in human retinal pigment epithelial cells.

AIM: To determine the expression and regulation of vascular endothelial growth factor C (VEGF-C), and its receptor VEGFR-3, in human retinal pigment epithelial (RPE) cells and to consider their angiogenic role in choroidal neovascularisation (CNV). METHOD: The expression of VEGF-C and VEGFR-3 in cultured human RPE was confirmed by immunostaining, PCR, western blotting, and ELISA. Cultured RPE cells were exposed to VEGF-A and glucose and VEGF-C and VEGFR-3 changes in gene expression determined by RT-PCR. Secreted VEGF-C protein in conditioned media from RPE was examined by western blotting and ELISA analysis. The ability of VEGF-C to elicit tube formation in choroidal endothelial cells was assayed by an in vitro Matrigel model. RESULT: VEGF-A and glucose upregulated VEGF-C mRNA expression and increased the secretion of VEGF-C protein into the culture medium. VEGF-A, but not glucose alone, stimulated VEGFR-3 mRNA expression. VEGF-C acted synergistically with VEGF-A to promote in vitro tube formation by choroidal endothelial cells. CONCLUSION: VEGF-A has a critical role in the orchestration of VEGF-C expression in RPE cells and the synergistic action of VEGF-C with VEGF-A may play an important part in the aetiology of CNV.

Loss of the antiangiogenic pigment epithelium-derived factor in patients with angiogenic eye disease.

Retinal neovascularization characterizes proliferative diabetic retinopathy (PDR). Pigment epithelium-derived factor (PEDF) has been shown to be a major antiangiogenic growth factor in the mammalian eye. PEDF expression is suppressed by hypoxia, and changes in PEDF have been correlated to the development of retinal neovascularization in animal models of hypoxic eye disease. However, whether this concept of a reduced angiogenesis inhibitor holds true in humans is as yet unclear. In this study, we analyzed the in vivo regulation of PEDF in patients with and without hypoxic eye disease. We used immunoblots to measure PEDF in ocular fluids obtained from 64 nondiabetic and diabetic patients. In addition, immunohistochemistry of PEDF was carried out in specimens of normal human retinas and retinas with various degrees of diabetic retinopathy. The PEDF concentrations in patients with PDR (P < 0.001) or extensive nondiabetic retinal neovascularization caused by retinal-vein occlusion (P < 0.001) were lower than in control patients. Levels of PEDF were replenished in PDR patients with previous retinal scatter photocoagulation compared with PDR patients without previous photocoagulation (P = 0.01). Immunohistochemistry revealed an interstitial staining pattern as expected for a secreted protein, with an intense staining in retinas of patients without proliferative eye disease. However, in patients with PDR, little or no staining was detectable. Our data strongly support the concept that retinal angiogenesis is induced by loss of the major angiogenesis inhibitor in the eye, PEDF, in combination with an increased expression of angiogenic growth factors such as vascular endothelial growth factor. Our findings suggest that substitution of angiogenesis inhibitors may be an effective approach in the treatment of PDR.

Do blue light filters confer protection against age-related macular degeneration?

Age-related macular degeneration (AMD) is a major health problem in the developed world accounting for approximately half of all blind registrations. Current treatment options are unsuitable for the majority of patients and therefore the identification of modifiable risk factors that may inform disease prevention programmes is a priority. This review evaluates the long-held belief that blue light exposure has a role in the pathogenesis of AMD. Laboratory evidence has demonstrated that photochemical reactions in the oxygen-rich environment of the outer retina lead to the liberation of cytotoxic reactive oxygen species (ROS). These ROS cause oxidative stress which is known to contribute to the development of AMD. The precise chromopore that may be involved in the pathogenesis of AMD is unclear but the age pigment lipofuscin is a likely candidate. Its aerobic photoreactivity and adverse effects on antioxidant activity combined with its gradual accumulation over time suggests that its in vivo phototoxicity increases with age despite changes in the absorption characteristics of the crystalline lens. Evidence from animal studies confirms blue light's damaging potential but the results are not directly applicable to macular degeneration in humans. Studies of human macular pigment density and the risk of AMD progression following cataract surgery lend further weight to the hypothesis that blue light exposure has a role in the pathogenesis of AMD but the epidemiological evidence is equivocal. On balance the evidences suggests but does not yet confirm that blue light is a risk factor for AMD. Given the socio-economic impact of this disease and urgent need to identify modifiable risk factors, future work should include a large-scale clinical trial to evaluate the effect of blue blocking filters on AMD progression rates.

Angiopoietin concentrations in diabetic retinopathy.

BACKGROUND/AIM: Angiopoietin 1 and 2 interact with vascular endothelial growth factor (VEGF) to promote angiogenesis in animal and in vitro models. Although VEGF concentrations are elevated, there is little information regarding angiopoietin concentration in the vitreous of patients with diabetic retinopathy. METHODS: Angiopoietin concentrations were measured by luminescence immunoassay in vitreous samples from 17 patients with non-proliferative diabetic retinopathy (NPDR) and clinically significant diabetic macular oedema (CSMO), 10 patients with proliferative diabetic retinopathy (PDR), and five patients with macular hole (controls) obtained at pars plana vitrectomy. RESULTS: Angiopoietin 1 concentrations were low in patients with macular hole (median 17 pg/ml) while in NPDR with CSMO they were 2002 pg/ml (range 289-5820 pg/ml) and in PDR 186 pg/ml (range 26-2292 pg/ml). Angiopoietin 2 concentrations in NPDR with CSMO were a median of 4000 pg/ml (range 1341-14 329 pg/ml). For both macular hole and PDR patients angiopoietin 2 was below the limit of detection. CONCLUSIONS: Angiopoietin 2 concentration was twice that of angiopoietin 1 in NPDR with CSMO. Angiopoietin 2 is the natural antagonist of angiopoietin 1 which is thought to act as an anti-permeability agent. The predominance of angiopoietin 2 may allow VEGF induced retinal vascular permeability in patients with CSMO. The relatively low concentration of both angiopoietin 1 and 2 in patients with proliferative diabetic retinopathy may reflect the established nature of the neovascularisation in cases proceeding to vitrectomy.

Risk behaviour, anti-HIV and anti-hepatitis B core prevalence in clinic and non-clinic samples of gay men in England, 1991-1992.

OBJECTIVE: To describe the sexual risk behaviour of and HIV and hepatitis B antibody prevalence in gay men in England. DESIGN: Cross-sectional. RESPONDENTS: Gay men recruited from community settings (bars, clubs, gay organizations) and genito-urinary clinics in London, Manchester, the Midlands and Bristol; men who participated in an earlier study. METHODS: Interview including demographic information, sexual behaviour, partner type and health service use. Subjects donated saliva, which was screened for antibodies to HIV-1 by immunoglobulin G (IgG) antibody capture enzyme-linked immunosorbent assay (GACELISA) and to hepatitis B core (HBc) antigen by IgG antibody capture radioimmunoassay (GACRIA). RESULTS: Ninety-four out of 580 (16.2%) men were HIV-antibody-positive; 6.2% of men aged < or = 25 years were positive versus 19.5% of men aged > or = 26 years. HIV-antibody prevalence was highest in London (21.1%), and twice that previously reported outside London (10.5%). Ninety-four out of 568 (16.5%) men were HBc-antibody-positive; 6.9% of men aged < or = 25 years were positive versus 19.7% of men aged > or = 26 years. Anti-HBc prevalence was highest in London (19.8 versus 12.7% outside London). Manual workers were more likely to be anti-HBc-positive, as were men who reported recent high-risk intercourse. Sexually transmitted diseases associated with frequent partner change (gonorrhoea, non-specific urethritis) were reported. CONCLUSION: The HIV epidemic in gay men in England continues, particularly outside London, where prevalence was double that of previous studies. We found relatively high rates of infection in young men whose main sexual experience has been in a time of unprecedented awareness of AIDS. Our data on hepatitis B suggests that further pro-active immunization programmes are urgently required. These findings add to concerns about provision of interventions targeting gay men.

Awareness of sexual partners' HIV status as an influence upon high-risk sexual behaviour among gay men.

OBJECTIVE: To evaluate the extent to which 'high-risk' sexual behaviour is influenced by awareness of partners' HIV status among gay men. DESIGN: Structured interviews and collection of saliva samples for anonymous linked testing for HIV-1 antibodies. SETTING: Genitourinary medicine clinics and the gay community. SUBJECTS: Men (n = 677) who reported sexual contact with another man in the last 5 years. RESULTS: The majority of respondents (63%) had had an HIV-antibody test. Analysis of data showed that in 15% of the respondents' 1380 partnerships, HIV status was known by both parties. However, the majority of partnerships involved only safe sex. Only 26% of the partnerships in which unprotected penetrative anal sex had occurred involved mutual knowledge of HIV status and was most likely to occur with regular rather than non-regular/causal partners. Logistic regression revealed that this latter association could not be explained in terms of mutual HIV status knowledge. CONCLUSIONS: Despite widespread HIV testing, the majority of gay men engaging in high-risk sex are unaware of their partner's HIV status.

PIP: The authors interviewed and collected saliva samples from 677 men who reported having sexual contact with other men in the preceding five years to assess the extent to which high-risk sexual behavior is influenced by awareness of partners' HIV status among gay men. Participants of mean age 32.6 years of a range of 16-71 years were recruited from genitourinary medicine clinics and the gay community over the period March 1991-April 1992. 52% were from London, 21% from Manchester, 18% from central England, 6% from Bristol, and 3% from elsewhere. 63% had previously had an HIV-antibody test. 94 (16%) of the 580 satisfactory saliva samples tested for HIV-1 antibodies were seropositive; 17 men were previously unaware of their HIV-positive serostatus. The 577 men who reported having a sex partner within the previous month provided information on 1380 partners during the period. 45% of the sexually active men reported engaging in some kind of penetrative anal sex in the previous month, while 23% reported having unprotected anal sex in the previous month. HIV status was known by both parties, however, in only 15% of the 1380 partnerships. 891 partnerships involved no penetrative anal sex and 1107 involved only nonpenetrative or penetrative sex always with a condom. Further, 26% of the partnerships in which unprotected penetrative anal sex took place involved mutual knowledge of HIV status and was most likely to occur with regular instead of nonregular/casual partners. It is of interest that 114 partners were known to be married and 311 were of unknown marital status. Higher social class was associated with a reduced likelihood of having risky sex and high-risk sex was more common in partnerships in which there was an age gap in excess of two years between partners.

Maize streak virus coat protein is karyophyllic and facilitates nuclear transport of viral DNA.

Transport of maize streak virus (MSV) DNA into the nucleus of host cells is essential for virus replication and the presence of virus particles in the nuclei of infected cells implies that coat protein (CP) must enter the nucleus. To see if CP is imported into the nucleus in the absence of other viral gene products, the MSV CP gene was expressed in insect cells with a baculovirus vector system, and also in tobacco protoplasts with a cauliflower mosaic virus (CaMV) 35S promoter-driven transient gene expression vector. Immunofluorescent staining showed that the CP accumulated in the nuclei of both insect and tobacco cells. Mutagenesis of a potential nuclear localization signal in the CP resulted in cytoplasmic accumulation of the mutant protein. We have shown previously that the CP binds to single-stranded (ss) and double-stranded (ds) viral DNA. To investigate if CP might also be involved in viral DNA nuclear transport, Escherichia coli-expressed CP, together with TOTO-1-labeled viral ss or ds DNA, was microinjected into maize and tobacco epidermal cells. Both ss and ds DNA moved into the nucleus when co-injected with the CP but not with E. coli proteins alone. These results suggest that, in addition to entering the nucleus where it is required for encapsidation of the viral ss DNA, the MSV CP facilitates the rapid transport of viral (ss or ds) DNA into the nucleus.

Cell-cycle, phase-specific activation of Maize streak virus promoters.

It is believed that geminiviral DNA replication is coupled to the cell-cycle regulatory complex of the plant cell and that the virus-early (complementary or C sense) gene products REP and REPA may be able to manipulate the regulation of the cycle. In this study, we examined expression from the promoters of Maize streak virus (MSV) in transgenic maize plants and cells to determine whether they showed cell-cycle specificity. Histochemical staining of plant roots containing "long and short" C-sense promoter sequences upstream of the GUS (beta-glucuronidase) reporter gene showed that promoter activity was restricted to the meristematic region of the roots and was enhanced by 2,4-dichlorophenoxy acetic acid (2,4-D) treatment. Analysis of reporter gene and cell-cycle-specific gene transcript levels coupled with flow cytometric data in synchronized transgenic maize cells revealed that all of the MSV promoters showed cell-cycle specificity. The coat protein gene promoter showed highest activity in early G2, whereas the C-sense promoter sequences produced two peaks of activity in the S and G2 cell-cycle phases.

Discrete regions of the sensor protein virA determine the strain-specific ability of Agrobacterium to agroinfect maize.

The ability of Agrobacterium strains to infect transformation-recalcitrant maize plants has been shown to be determined mainly by the virA locus, implicating vir gene induction as the major factor influencing maize infection. In this report, we further explore the roles of vir induction-associated bacterial factors in maize infection using the technique of agroinfection. The Ti plasmid and virA source are shown to be important in determining the ability of a strain to infect maize, and the monosaccharide binding protein ChvE is absolutely required for maize agroinfection. The linker domain of VirAC58 from an agroinfection-competent strain, C58, is sufficient to convert VirAA6 of a nonagroinfecting strain, A348,to agroinfection competence. The periplasmic domain of VirAC58 is also able to confer a moderate level of agroinfection competence to VirAA6. In addition, the VirAA6 protein from A348 is agroinfection competent when removed from its cognate Ti plasmid background and placed in a pTiC58 background. The presence of a pTiA6-encoded, VirAA6-specific inhibitor is hypothesized and examined.