Indigenizing and Ruralizing NCI Screen to Save Program: Resources, Optimizing Outreach, Teaching, Science (ROOTS).

Colorectal cancer (CRC) is a complex health disparity in many Indigenous and rural populations. While it affects anyone regardless of race, age, gender, or other common differences among people, Indigenous and rural populations are at a higher risk of dying from colorectal cancer. An NCI Screen to Save (S2S) program was culturally tailored to promote awareness and knowledge of colorectal cancer and screening in both Indigenous and rural communities across a sector in Northeastern USA. Indigenous and rural community outreach teams at an NCI-designated cancer center partnered with a community advisory board to provide an indigenized/ruralized version of the NCI Screen to Save program delivered to both Indigenous and rural/suburban communities. In total, n = 79 pre/post surveys were obtained from n = 82 participants, who had an average age of 49 years. Findings demonstrated that Indigenous/rural participants in both off-territory/non-reservation communities and a tribal community that received a culturally tailored version of NCI's S2S program were able to identify both smoking and tobacco use along with lack of physical activity as risk factors for colorectal cancer. Post-intervention, participants reported being more likely to increase physical activity. Most importantly, participants said they would be more likely to be screened for colorectal cancer along with their family and friends based on their cancer screening experiences. Culturally tailored CRC messaging is an effective means for increasing screening intentions and decreasing cancer health disparities among both indigenous and rural populations. Future research should include the relationship of diet to obesity-related cancers, greater integration of Indigenous-rural patient navigation programs, creation of more information on genetic screening, and quality improvement to service translational science initiatives.

Understanding social network support, composition, and structure among cancer caregivers.

OBJECTIVE: We examined the social network support, composition, and structure of pediatric cancer caregivers. METHODS: We used a self-report survey to collect egocentric social network data from 107 caregivers of pediatric cancer patients and calculated descriptive statistics to examine cancer-related support network composition, function, and structure. We then ran logistic regressions to examine the relationships between network characteristics and overall satisfaction with social support. RESULTS: Family members were the most common source of emotional support and logistical support, and health care providers were the most common source of informational support. Participants perceived the "most helpful" forms of support as being: (1) emotional support from family and health care providers; (2) informational support from health care providers and other cancer caregivers; and (3) logistical support from family. Overall, caregivers wished that 9.8% of their network ties had provided more support, with family members being the most common alter type to disappoint caregivers and offer less support than needed/expected. Caregivers who reported higher network disappointment (having network members who offered less support than needed/expected) were significantly less satisfied with emotional support than those with lower network disappointment (Odds Ratio = 0.18, p = 0.02), and caregivers with higher network disappointment were significantly less satisfied with logistical support compared to those with lower network disappointment (Odds Ratio = 0.14, p = 0.01). CONCLUSION: Our results show differences in the nature of social support provided by different types of network members. These findings have implications for tailoring social network interventions to improve caregiver and family outcomes.

Importance of biofilm formation for promoting plant growth under salt stress in Pseudomonas putida KT2440.

An underutilized experimental design was employed to isolate adapted mutants of the model bacterium Pseudomonas putida KT2440. The design involved subjecting a random pool of mini-Tn5 mutants of P. putida KT2440 to multiple rounds of selection in the rhizosphere of soybean plants irrigated with a NaCl solution. The isolated adapted mutants, referred to as MutAd, exhibited a mutation in the gene responsible for encoding the membrane-binding protein LapA, which plays a role in the initial stages of biofilm formation on abiotic surfaces. Two MutAd bacteria, MutAd160 and MutAd185, along with a lapA deletion mutant, were selected for further investigation to examine the impact of this gene on salt tolerance, rhizosphere fitness, production of extracellular polymeric substances (EPS), and promotion of plant growth. Despite the mutants' inability to form biofilms, they were able to attach to soybean seeds and roots. The MutAd bacteria demonstrated an elevated production of EPS when cultivated under saline conditions, which likely compensated for the absence of biofilm formation. MutAd185 bacteria exhibited enhanced root attachment and promoted the growth of soybean plants in slightly saline soils. The proposed experimental design holds promise for expediting bacterial adaptation to the rhizosphere of plants under specific environmental conditions, identifying genetic mutations that enhance bacterial fitness in those conditions, and thereby increasing their capacity to promote plant growth.

An initial investigation of using smartphone-enabled micro-temporal data collection to increase acceptability, feasibility, and validity of research on cancer caregiving.

PURPOSE: Smartphone-enabled micro-temporal data collection has potential to increase reliability, validity, and feasibility of participant-reported data and is a promising strategy for pediatric oncology supportive care and quality-of-life research. Given the demands of pediatric cancer caregiving, we sought to understand the feasibility and acceptability of smartphone data collection that included short surveys administered daily for 14 days via text message link. METHODS: We recruited pediatric cancer caregivers, whose children (ages 0-18 years) were on active treatment, to complete a 14-day daily survey study via smartphone. We implemented our study procedures and examined feasibility through study enrollment rates, reasons for refusal, retention rates, number of reminders and number of completed surveys. We examined acceptability using caregiver ratings of survey length, burden, and ease of completion on a smartphone. RESULTS: We recruited (N = 75) caregivers to the study and had an 84% enrollment rate. Reasons for declining participation included passive refusal (n = 13) and too busy (n = 1). The participant retention rate was 100% and compliance with daily survey completion was 99%. Most surveys were completed following two prompts and took participants 5 minutes or less to complete. Caregivers rated the surveys as easy to complete, low burden, and just right in length. CONCLUSION: A daily self-report, using a brief (≤5 minutes) survey administered on a smartphone via text message prompt, is a feasible and acceptable method. Future research should extend these findings to understand the generalizability across pediatric cancer caregiving contexts.

Behavioral parenting skills as a novel target for improving medication adherence in young children: Feasibility and acceptability of the CareMeds intervention.

In pediatric cancer care, medication non-adherence is a significant driver of avoidable suffering and death. There is a lack of interventions designed for families of young children, where patient medication refusal/avoidance is a common barrier to adherence. We developed the CareMeds intervention which focuses on caregiver skills training to help young children take medicine calmly and without use of restraint techniques. The goal of this preliminary study was to assess the acceptability and feasibility of the CareMeds intervention. Caregivers of pediatric cancer patients (ages 2-10) whose children were on a home-based oral medication regimen were recruited to participate. Feasibility was examined through study enrollment and retention rates as well as reasons for refusal and drop out. Acceptability was evaluated through usability of and engagement with intervention components and an acceptability questionnaire. Feasibility: We recruited N = 9 caregivers to participate in this intervention pilot study and had a 75% enrollment rate. Reasons for declining included scheduling concerns (n = 2) and lack of interest (n = 1). The participant retention rate was 100% with 100% adherence to intervention sessions. Acceptability: Parents rated the sessions and resource materials as acceptable and reported frequent use of skills taught in the intervention. The CareMeds intervention is an acceptable and feasible strategy for caregivers of pediatric cancer patients and warrants future research to examine the efficacy of behavioral parenting skills interventions to improve medication adherence in young children.

Plant growth promotion by Pseudomonas putida KT2440 under saline stress: role of eptA.

New strategies to improve crop yield include the incorporation of plant growth-promoting bacteria in agricultural practices. The non-pathogenic bacterium Pseudomonas putida KT2440 is an excellent root colonizer of crops of agronomical importance and has been shown to activate the induced systemic resistance of plants in response to certain foliar pathogens. In this work, we have analyzed additional plant growth promotion features of this strain. We show it can tolerate high NaCl concentrations and determine how salinity influences traits such as the production of indole compounds, siderophore synthesis, and phosphate solubilization. Inoculation with P. putida KT2440 significantly improved seed germination and root and stem length of soybean and corn plants under saline conditions compared to uninoculated plants, whereas the effects were minor under non-saline conditions. Also, random transposon mutagenesis was used for preliminary identification of KT2440 genes involved in bacterial tolerance to saline stress. One of the obtained mutants was analyzed in detail. The disrupted gene encodes a predicted phosphoethanolamine-lipid A transferase (EptA), an enzyme described to be involved in the modification of lipid A during lipopolysaccharide (LPS) biosynthesis. This mutant showed changes in exopolysaccharide (EPS) production, low salinity tolerance, and reduced competitive fitness in the rhizosphere.

Analytical Problems and Suggestions in the Analysis of Behavioral Economic Demand Curves.

Behavioral economic demand curves (Hursh, Raslear, Shurtleff, Bauman, & Simmons, 1988) are innovative approaches to characterize the relationships between consumption of a substance and its price. In this article, we investigate common analytical issues in the use of behavioral economic demand curves, which can cause inconsistent interpretations of demand curves, and then we provide methodological suggestions to address those analytical issues. We first demonstrate that log transformation with different added values for handling zeros changes model parameter estimates dramatically. Second, demand curves are often analyzed using an overparameterized model that results in an inefficient use of the available data and a lack of assessment of the variability among individuals. To address these issues, we apply a nonlinear mixed effects model based on multivariate error structures that has not been used previously to analyze behavioral economic demand curves in the literature. We also propose analytical formulas for the relevant standard errors of derived values such as P max, O max, and elasticity. The proposed model stabilizes the derived values regardless of using different added increments and provides substantially smaller standard errors. We illustrate the data analysis procedure using data from a relative reinforcement efficacy study of simulated marijuana purchasing.

Functional and structural study of the dimeric inner membrane protein SbmA.

SbmA protein has been proposed as a dimeric secondary transporter. The protein is involved in the transport of microcins B17 and J25, bleomycin, proline-rich antimicrobial peptides, antisense peptide phosphorodiamidate morpholino oligomers, and peptide nucleic acids into the Escherichia coli cytoplasm. The sbmA homologue is found in a variety of bacteria, though the physiological role of the protein is hitherto unknown. In this work, we carried out a functional and structural analysis to determine which amino acids are critical for the transport properties of SbmA. We created a set of 15 site-directed sbmA mutants in which single conserved amino acids were replaced by glycine residues. Our work demonstrated that strains carrying the site-directed mutants V102G, F219G, and E276G had a null phenotype for SbmA transport functions. In contrast, strains carrying the single point mutants W19G, W53G, F60G, S69G, N155G, R190, L233G, A344G, T255G, N308G, and R385G showed transport capacities indistinguishable from those of strains harboring a wild-type sbmA. The strain carrying the Y116G mutant exhibited mixed phenotypic characteristics. We also demonstrated that those sbmA mutants with severely impaired transport capacity showed a dominant negative phenotype. Electron microscopy data and in silico three-dimensional (3D) homology modeling support the idea that SbmA forms a homodimeric complex, closely resembling the membrane-spanning region of the ATP-binding cassette transporter family. Direct mapping of the sbmA single point mutants on the protein surface allowed us to explain the observed phenotypic differences in transport ability.

Macrophage environment turns otherwise MccJ25-resistant Salmonella into sensitive.

BACKGROUND: Microcin J25 (MccJ25) is a plasmid-encoded antibiotic peptide produced by Escherichia coli (E. coli). MccJ25 enters into the sensitive E. coli strains by the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD and SbmA. The resistance of Salmonella enterica serovar Typhimurium (S. Typhimurium) to MccJ25 is attributed to the inability of its FhuA protein to incorporate the antibiotic into the cell. RESULTS: In this work we demonstrate that S. Typhimurium becomes notably susceptible to MccJ25 when replicating within macrophages. In order to determine the possible cause of this phenomenon, we studied the sensitivity of S. Typhimurium to MccJ25 at conditions resembling those of the internal macrophage environment, such as low pH, low magnesium and iron deprivation. We observed that the strain was only sensitive to the antibiotic at low pH, leading us to attribute the bacterial sensitization to this condition. A MccJ25-resistant E. coli strain in which fhuA is deleted was also inhibited by the antibiotic at low pH. Then, we could assume that the MccJ25 sensitivity change observed in both E. coli fhuA and S. Typhimurium is mediated by a MccJ25 uptake independent of the FhuA receptor. Moreover, low pH incubation also sensitized S. Typhimurium to the hydrophobic antibiotic novobiocin, which does not affect enteric bacteria viability because it is unable to penetrate the bacterial outer membrane. This observation supports our hypothesis about low pH producing a modification in the bacterial membrane permeability that allows an unspecific MccJ25 uptake. On the other hand, MccJ25 inhibited S. Typhimurium when cells were preincubated in acidic pH medium and then treated at neutral pH with the antibiotic. CONCLUSIONS: Our results suggest that acidic condition does not alter MccJ25 hydrophobicity but irreversibly modifies bacterial membrane permeability. This would allow an unspecific antibiotic uptake into the cell.From our data it is possible to infer that intracellular pathogenic strains, which are in vitro resistant to MccJ25, could become susceptible ones in vivo. Therefore, the MccJ25 action spectrum would be broader than what in vitro experiments indicate.

Less is more: Enterobactin concentration dependency in copper tolerance and toxicity.

The ability of siderophores to play roles beyond iron acquisition has been recently proven for many of them and evidence continues to grow. An earlier work showed that the siderophore enterobactin is able to increase copper toxicity by reducing Cu2+ to Cu+, a form of copper that is more toxic to cells. Copper toxicity is multifaceted. It involves the formation of reactive oxygen species (ROS), mismetallation of enzymes and possibly other mechanisms. Given that we previously reported on the capacity of enterobactin to alleviate oxidative stress caused by various stressors other than copper, we considered the possibility that the siderophore could play a dual role regarding copper toxicity. In this work, we show a bimodal effect of enterobactin on copper toxicity (protective and harmful) which depends on the siderophore concentration. We found that the absence of enterobactin rendered Escherichia coli cells more sensitive to copper, due to the reduced ability of those cells to cope with the metal-generated ROS. Consistently, addition of low concentrations of the siderophore had a protective effect by reducing ROS levels. We observed that in order to achieve this protection, enterobactin had to enter cells and be hydrolyzed in the cytoplasm. Further supporting the role of enterobactin in oxidative stress protection, we found that both oxygen and copper, induced the expression of the siderophore and also found that copper strongly counteracted the well-known downregulation effect of iron on enterobactin synthesis. Interestingly, when enterobactin was present in high concentrations, cells became particularly sensitive to copper most likely due to the Cu2+ to Cu+ reduction, which increased the metal toxicity leading to cell death.

Redox-active tyrosine residue in the microcin J25 molecule.

Microcin J25 (MccJ25) is a 21 amino acid lasso-peptide antibiotic produced by Escherichia coli and composed of an 8-residues ring and a terminal 'tail' passing through the ring. We have previously reported two cellular targets for this antibiotic, bacterial RNA polymerase and the membrane respiratory chain, and shown that Tyr9 is essential for the effect on the membrane respiratory chain which leads to superoxide overproduction. In the present paper we investigated the redox behavior of MccJ25 and the mutant MccJ25 (Y9F). Cyclic voltammetry measurements showed irreversible oxidation of both Tyr9 and Tyr20 in MccJ25, but infrared spectroscopy studies demonstrated that only Tyr9 could be deprotonated upon chemical oxidation in solution. Formation of a long-lived tyrosyl radical in the native MccJ25 oxidized by H2O2 was demonstrated by Electron Paramagnetic Resonance Spectroscopy; this radical was not detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.

Antimicrobial activity of MccJ25(G12Y) against gram-negative foodborne pathogens in vitro and in food models.

The use of bacteriocins is a promising alternative to improve food security through the biocontrol of food pathogens and spoilage microorganisms. Gram-negative produced microcin J25(G12Y), known as (MccJ25(G12Y)) is a variant of the well-studied and characterized antimicrobial peptide, microcin J25 (MccJ25). In the present work, we explored the activity of this microcin against Gram-negative bacteria linked to foodborne diseases. We evaluated the in vitro antimicrobial activity of MccJ25(G12Y) in solid medium against a collection of pathogenic and food-altering strains and studied its activity and stability in meat and dairy food systems. We show that MccJ25(G12Y) exhibited the same in vitro antimicrobial spectrum as its parental microcin (MccJ25) against different Gram-negative foodborne pathogens and spoilage strains. We highlight that low concentrations of MccJ25(G12Y) between 0.45 and 29.4 µM were able to inhibit a substantial number of pathogens, including Salmonella, Escherichia, Shigella and Enterobacter genus. We also demonstrate the antimicrobial effectiveness of the peptide against Escherichia coli O157:H7 NCTC 12900, Enterobacter cloacae CECT 194, and Salmonella enterica CECT 4396 in fish and beef burgers and yogurt. MccJ25(G12Y) was added or not to food matrices inoculated with the foodborne pathogens at 105 CFU/g or mL. Afterward, food products were stored at 4 °C and selective media for the specific enumeration were used to determine the antimicrobial susceptibility of each pathogen to MccJ25(G12Y). The viability of the three pathogens was significantly reduced in the different food biological environments. In yogurt, the peptide decreased E. coli numbers on day 5 by about 4 log 10 CFU/mL as compared to non-treated samples. For S. enterica and E. cloacae no viable cells were detected at the end of the treatment. Adding MccJ25(G12Y) to fish burgers decreased E. cloacae numbers during storage 2 log10 CFU/g on the first day, reaching a difference of about 5 log 10 CFU/g after 10 days compared to non-treated control. Finally, the peptide decreased E. coli O157:H7 numbers on the beef burgers samples during storage on day 10 by about 3 log 10 CFU/g as compared to non-treated samples. The stability analysis demonstrated that MccJ25(G12Y) is capable of remaining active in these food matrices for a considerable time during the storage at refrigeration temperatures. These results reinforce the studies on the potential applicability of this microcin as a biopreservative in the food industry.

Sensitization of microcin J25-resistant strains by a membrane-permeabilizing peptide.

Microcin J25 (MccJ25) is a plasmid-encoded, 21-amino-acid, antibacterial peptide produced by Escherichia coli. MccJ25 inhibits RNA polymerase and the membrane respiratory chain. MccJ25 uptake into E. coli-sensitive strains is mediated by the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD, and SbmA. This peptide is active on some E. coli, Salmonella, and Shigella species strains, while other Gram-negative bacteria, such as clinical isolates of Enterobacter cloacae, Citrobacter freundii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Moraxella catarrhalis, and Salmonella enterica serovar Typhimurium, are completely resistant. In the present work, we demonstrated that the membrane-permeabilizing peptide (KFF)3K made some resistant strains sensitive to MccJ25, among them S. Typhimurium, where the antibiotic inhibits in vitro cell growth and bacterial replication within macrophages. The results demonstrate that the membrane permeabilization induced by (KFF)3K allows MccJ25 penetration in an FhuA and SbmA-independent manner and suggest that the combination of both peptides could be considered as a therapeutic agent against pathogenic Salmonella strains.

A preliminary test of a brief intervention to lessen young adults' cannabis use: Episode-level smartphone data highlights the role of protective behavioral strategies and exercise.

Brief interventions are increasingly being used to help young adults to moderate their cannabis use. We conducted a randomized clinical trial of a brief (4 weekly sessions), in-person intervention that included a smartphone application that reinforced the use of protective behavioral strategies (PBSs) to lessen cannabis use. Young adults (N = 37; 24 men) who regularly used cannabis were randomized to 2 intervention conditions rooted in cognitive-behavioral therapy (CBT) and motivational enhancement therapy (MET). Along with learning CBT + MET strategies, participants in 1 of the conditions were instructed to engage in exercise. All participants used smartphone-based ecological momentary assessment to provide episode-level reports about use of cannabis and PBSs. Two multilevel structural equation models were run to test the study hypotheses that (a) cannabis use would be reduced over the course of the 6-month study, (b) reductions would be moderated by intervention condition, and (c) episode-level PBS use would predict episode-level cannabis use. Participants reduced their cannabis use by approximately 1 half of a standard joint per time point. The MET + CBT + Exercise condition reduced cannabis use to a greater degree than did the MET + CBT condition. With episode-level PBS use in the model, reductions in cannabis use were independent of intervention condition. Our findings suggest that young adults will engage with a smartphone app that serves as a component of an in-person intervention to moderate their cannabis use. Intervention content that promotes the use of PBSs and exercise facilitates reductions in cannabis use. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The leucine-responsive regulatory protein, Lrp, modulates microcin J25 intrinsic resistance in Escherichia coli by regulating expression of the YojI microcin exporter.

Many Escherichia coli K-12 strains display an intrinsic resistance to the peptide antibiotic microcin J25. In this study, we present results showing that the leucine-responsive regulatory protein, Lrp, is involved in this phenotype by acting as a positive regulator of YojI, a chromosomally encoded efflux pump which expels microcin out of cells. Exogenous leucine antagonizes the effect of Lrp, leading to a diminished expression of the pump and an increased susceptibility to microcin J25.

The structure and biological aspects of peptide antibiotic microcin J25.

Microcin J25 (MccJ25) is a plasmid-encoded peptide of 21 L-amino acids (G1-G-A-G-H5-V-P-E-Y-F10-V-G-I-G-T15-P-I-S-F-Y20-G), excreted to the medium by an Escherichia coli strain. MccJ25 is active on Gram-negative bacteria related to the producer strain, including some pathogenic strains. The four-plasmid genes mcjABCD, are involved in MccJ25 production: mcjA encodes a 58-residue precursor, mcjB and mcjC codify two processing enzymes required for the in vivo synthesis of the mature peptide and mcjD encodes the immunity protein (McjD), a member of the super family of ABC transporters. Immunity is mediated by active efflux of the peptide, keeping its intracellular concentration below a critical level. YojI, a chromosomal protein with ATP-binding-cassette-type exporter homology, is also able to export MccJ25. The E. coli outer membrane protein, TolC, is necessary for MccJ25 secretion mediated by either McjD or YojI. The uptake of MccJ25 is dependent on the outer-membrane receptor FhuA and the four inner-membrane proteins TonB, ExbD, ExbB and SbmA. At least two mechanisms described the action of MccJ25 on the target cells: (1) inhibition of the RNA-polymerase (RNAP) activity by obstructing the secondary channel, and consequently, preventing the access of the substrates to its active sites; and (2) operating on the cell membrane, MccJ25 disrupts the electric potential inhibiting the oxygen consumption in Salmonella enterica. MccJ25 also inhibits oxygen consumption and the respiratory chain enzymes in E. coli throughout the increasing of ROS concentration. Nevertheless the exact mechanism of this phenomenon must be elucidated. The MccJ25 exhibits a prolonged antimicrobial activity in a mouse infection model, suggesting a noteworthy potential for therapeutic uses.

Potential applicability of chymotrypsin-susceptible microcin J25 derivatives to food preservation.

Microcin J25 (MccJ25) is a 21-residue ribosomally synthesized lariat peptide antibiotic. MccJ25 is active against such food-borne disease-causing pathogens as Salmonella spp., Shigella spp., and Escherichia coli, including E. coli O157:H7 and non-O157 strains. MccJ25 is highly resistant to digestion by proteolytic enzymes present in the stomach and intestinal contents. MccJ25 would therefore remain active in the gastrointestinal tract, affecting normal intestinal microbiota, and this limits the potential use of MccJ25 as a food preservative. In the present paper, we describe a chymotrypsin-susceptible MccJ25 derivative with a mutation of Gly(12) to Tyr that retained almost full antibiotic activity and efficiently inhibited the growth of pathogenic Salmonella enterica serovar Newport and Escherichia coli O157:H7 in skim milk and egg yolk. However, unlike the wild-type MccJ25, the MccJ25(G12Y) variant was inactivated by digestive enzymes both in vitro and in vivo. To our knowledge, our results represent the first example of a rational modification of a microcin aimed at increasing its potential use in food preservation.

A combination of sbmA and tolC mutations in Escherichia coli K-12 Tn10-carrying strains results in hypersusceptibility to tetracycline.

Previously, we demonstrated that Escherichia coli tolC mutations reduce the high-level resistance to tetracycline afforded by the transposon Tn10-encoded TetA pump from resistance at 200 microg/ml to resistance at 40 microg/ml. In this study, we found that the addition of an sbmA mutation to a tolC::Tn10 mutant exacerbates this phenotype: the double mutant did not form colonies, even in the presence of tetracycline at a concentration as low as 5 microg/ml. Inactivation of sbmA alone partially inhibited high-level tetracycline resistance, from resistance at 200 microg/ml to resistance at 120 microg/ml. There thus appears to be an additive effect of the mutations, resulting in almost complete suppression of the phenotypic expression of Tn10 tetracycline resistance.

Protective action of ppGpp in microcin J25-sensitive strains.

As Escherichia coli strains enter the stationary phase of growth they become more resistant to the peptide antibiotic microcin J25. It is known that starvation for nutrients such as amino acids or glucose leads to increases in guanosine 3',5'-bispyrophosphate (ppGpp) levels and that the intracellular concentration of this nucleotide increases as cells enter the stationary phase of growth. Therefore, we examined the effects of artificially manipulating the ppGpp levels on sensitivity to microcin J25. A direct correlation was found between ppGpp accumulation and microcin resistance. Our results indicate that the nucleotide is required to induce production of YojI, a chromosomally encoded efflux pump which, in turn, expels microcin from cells. This would maintain the intracellular level of the antibiotic below a toxic level.

Factors affecting agreement between severely mentally ill alcohol abusers' and collaterals' reports of alcohol and other substance abuse.

This study examined subject-collateral reports of alcohol use among a sample of 167 dually diagnosed individuals seeking outpatient treatment at a community mental health clinic. All subjects met Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) criteria for a schizophrenia-spectrum or bipolar disorder and for alcohol abuse or dependence. Subjects were recruited within 2 weeks of treatment entry and completed measures of cognitive functioning, alcohol dependence severity, psychiatric symptoms, and quantity and frequency of substance use over the previous 60 days using the Timeline Follow-Back interview (L. C. Sobell & M. B. Sobell, 1996). They also provided a urine sample, which was screened for recent drug use. Collateral interviews were conducted by phone and included an assessment of the subject's alcohol and drug use over the same 60-day period. Collaterals also reported their confidence in the accuracy of their reports. Overall, the results indicated generally poor subject-collateral agreement. However, subject-collateral agreement appeared better for those individuals (n = 97) with negative urine drug screens. The most consistent predictor of subject-collateral discrepancy scores was subjects' recent drug use. Recommendations for enhancing the validity of self-reports of substance use in a severely mentally ill population are discussed.