Background This paper describes the methods and conceptual framework for Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study data collection. The National Institutes of Health, through the National Institute on Drug Abuse, is partnering with the Food and Drug Administration’s (FDA) Center for Tobacco Products to conduct the PATH Study under a contract with Westat. Methods The PATH Study is a nationally representative, longitudinal cohort study of 45 971 adults and youth in the USA, aged 12 years and older. Wave 1 was conducted from 12 September 2013 to 15 December 2014 using Audio Computer-Assisted Self-Interviewing to collect information on tobacco-use patterns, risk perceptions and attitudes towards current and newly emerging tobacco products, tobacco initiation, cessation, relapse behaviours and health outcomes. The PATH Study’s design allows for the longitudinal assessment of patterns of use of a spectrum of tobacco products, including initiation, cessation, relapse and transitions between products, as well as factors associated with use patterns. Additionally, the PATH Study collects biospecimens from consenting adults aged 18 years and older and measures biomarkers of exposure and potential harm related to tobacco use. Conclusions The cumulative, population-based data generated over time by the PATH Study will contribute to the evidence base to inform FDA’s regulatory mission under the Family Smoking Prevention and Tobacco Control Act and efforts to reduce the Nation’s burden of tobacco-related death and disease.

BACKGROUND Noncigarette tobacco products are evolving rapidly, with increasing popularity in the United States. METHODS We present prevalence estimates for 12 types of tobacco products, using data from 45,971 adult and youth participants (≥12 years of age) from Wave 1 (September 2013 through December 2014) of the Population Assessment of Tobacco and Health (PATH) Study, a large, nationally representative, longitudinal study of tobacco use and health in the United States. Participants were asked about their use of cigarettes, e-cigarettes, traditional cigars, cigarillos, filtered cigars, pipe tobacco, hookah, snus pouches, other smokeless tobacco, dissolvable tobacco, bidis, and kreteks. Estimates of the prevalence of use for each product were determined according to use category (e.g., current use or use in the previous 30 days) and demographic subgroup, and the prevalence of multiple-product use was explored. RESULTS More than a quarter (27.6%) of adults were current users of at least one type of tobacco product in 2013 and 2014, although the prevalence varied depending on use category. A total of 8.9% of youths had used a tobacco product in the previous 30 days; 1.6% of youths were daily users. Approximately 40% of tobacco users, adults and youths alike, used multiple tobacco products; cigarettes plus e-cigarettes was the most common combination. Young adults (18 to 24 years of age), male adults and youths, members of racial minorities, and members of sexual minorities generally had higher use of tobacco than their counterparts. CONCLUSIONS During this study, 28% of U.S. adults were current users of tobacco, and 9% of youths had used tobacco in the previous 30 days. Use of multiple products was common among tobacco users. These findings will serve as baseline data to examine between-person differences and within-person changes over time in the use of tobacco products. (Funded by the National Institute on Drug Abuse and the Food and Drug Administration.)

XopN is a virulence factor from Xanthomonas campestris pathovar vesicatoria (Xcv) that is translocated into tomato (Solanum lycopersicum) leaf cells by the pathogen's type III secretion system. Xcv DxopN mutants are impaired in growth and have reduced ability to elicit disease symptoms in susceptible tomato leaves. We show that XopN action in planta reduced pathogen-associated molecular pattern (PAMP)-induced gene expression and callose deposition in host tissue, indicating that XopN suppresses PAMP-triggered immune responses during Xcv infection. XopN is predicted to have irregular, a-helical repeats, suggesting multiple protein-protein interactions in planta. Consistent with this prediction, XopN interacted with the cytosolic domain of a Tomato Atypical Receptor-Like Kinase1 (TARK1) and four Tomato Fourteen-ThreeThree isoforms (TFT1, TFT3, TFT5, and TFT6) in yeast. XopN/TARK1 and XopN/TFT1 interactions were confirmed in planta by bimolecular fluorescence complementation and pull-down analysis. Xcv DxopN virulence defects were partially suppressed in transgenic tomato leaves with reduced TARK1 mRNA levels, indicating that TARK1 plays an important role in the outcome of Xcv-tomato interactions. These data provide the basis for a model in which XopN binds to TARK1 to interfere with TARK1-dependent signaling events triggered in response to Xcv infection.

We demonstrate that XopD, a type III effector from Xanthomonas campestris pathovar vesicatoria (Xcv), suppresses symptom production during the late stages of infection in susceptible tomato (Solanum lycopersicum) leaves. XopD-dependent delay of tissue degeneration correlates with reduced chlorophyll loss, reduced salicylic acid levels, and changes in the mRNA abundance of senescence- and defense-associated genes despite high pathogen titers. Subsequent structure-function analyses led to the discovery that XopD is a DNA binding protein that alters host transcription. XopD contains a putative helix-loop-helix domain required for DNA binding and two conserved ERF-associated amphiphilic motifs required to repress salicylic acid– and jasmonic acid–induced gene transcription in planta. Taken together, these data reveal that XopD is a unique virulence factor in Xcv that alters host transcription, promotes pathogen multiplication, and delays the onset of leaf chlorosis and necrosis.