The Practical Haplotype Graph, a platform for storing and using pangenomes for imputation.

MOTIVATION: Pangenomes provide novel insights for population and quantitative genetics, genomics and breeding not available from studying a single reference genome. Instead, a species is better represented by a pangenome or collection of genomes. Unfortunately, managing and using pangenomes for genomically diverse species is computationally and practically challenging. We developed a trellis graph representation anchored to the reference genome that represents most pangenomes well and can be used to impute complete genomes from low density sequence or variant data. RESULTS: The Practical Haplotype Graph (PHG) is a pangenome pipeline, database (PostGRES & SQLite), data model (Java, Kotlin or R) and Breeding API (BrAPI) web service. The PHG has already been able to accurately represent diversity in four major crops including maize, one of the most genomically diverse species, with up to 1000-fold data compression. Using simulated data, we show that, at even 0.1× coverage, with appropriate reads and sequence alignment, imputation results in extremely accurate haplotype reconstruction. The PHG is a platform and environment for the understanding and application of genomic diversity. AVAILABILITY AND IMPLEMENTATION: All resources listed here are freely available. The PHG Docker used to generate the simulation results is https://hub.docker.com/ as maizegenetics/phg:0.0.27. PHG source code is at https://bitbucket.org/bucklerlab/practicalhaplotypegraph/src/master/. The code used for the analysis of simulated data is at https://bitbucket.org/bucklerlab/phg-manuscript/src/master/. The PHG database of NAM parent haplotypes is in the CyVerse data store (https://de.cyverse.org/de/) and named/iplant/home/shared/panzea/panGenome/PHG_db_maize/phg_v5Assemblies_20200608.db. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Proposed domains for assessing postpartum recovery: a concept elicitation study.

OBJECTIVE: To propose postpartum recovery domains. DESIGN: Concept elicitation study. SETTING: Semi-structured interviews. POPULATION: Ten writing committee members and 50 stakeholder interviews (23 postpartum women, nine general obstetricians, five maternal and fetal medicine specialists, eight nurses and five obstetric anaesthetists). METHODS: Alternating interviews and focus group meetings until concept saturation was achieved (no new themes discussed in three consecutive interviews). Interviews were digitally recorded and transcribed, and an iterative coding process was used to identify domains. MAIN OUTCOME MEASURES: The primary outcome was to identify recovery domains. We also report key symptoms and concerns. Discussion frequency and importance scores (0-100; 0 = not important; 100 = vitally important to recovery) were used to rank domains. Discussion frequency was used to rank factors helping and hindering recovery, and to determine the greatest challenges experienced postpartum. RESULTS: Thirty-four interviews and two focus group meetings were performed. The 13 postpartum recovery domains identified, (ranked highest to lowest) were: psychosocial distress, surgical/medical factors, infant feeding and breast health, psychosocial support, pain, physical function, sleep, motherhood experience, infant health, fatigue, appearance, sexual function and cognition. The most frequently discussed factors facilitating postpartum recovery were: family support, lactation/breastfeeding support and partner support. The most frequently discussed factor hindering recovery was inadequate social support. The most frequent challenges reported were: breastfeeding (week 1), breastfeeding (week 3) and sleep (week 6). CONCLUSIONS: We propose 13 domains that comprehensively describe recovery in women delivering in a single centre within the USA. This provides a novel framework to study the postpartum recovery process. TWEETABLE ABSTRACT: We propose 13 postpartum recovery domains that provide a framework to study the recovery process following childbirth.

Pentraxin 3 in primary percutaneous coronary intervention for ST elevation myocardial infarction is associated with early irreversible myocardial damage : Kinetic profile, relationship to interleukin 6 and infarct size.

BACKGROUND: The inflammatory marker long pentraxin 3 (PTX3) has been shown to be a strong predictor of 30-day and one-year mortality after acute myocardial infarction. The aim of this study was to evaluate the kinetic profile of PTX3 and its relationship with interleukin 6 (IL-6), high-sensitive C-reactive protein (hs-CRP) and infarct size. METHODS: PTX3, IL-6 and hs-CRP were measured at predefined time points, at baseline (before percutaneous coronary intervention (PCI)), at 12 and 72 hours after PCI in 161 patients with first-time ST elevation myocardial infarction (STEMI). RESULTS: PTX3 and IL-6 levels increased in the early phase, followed by a gradual decrease between 12 and 72 hours. There were statistically significant correlations between PTX3 and IL-6 in general, for all time points and for changes over time (0-72 hours). In a linear mixed model, PTX3 predicted IL-6 (p < 0.001). PTX3 is also correlated with hs-CRP in general, and at each time point post PCI, except at baseline. PTX3, IL-6 and hs-CRP were all significantly correlated with infarct size in general, and at the peak time point for maximum troponin I. In addition, there was a modest correlation between IL-6 levels at baseline and infarct size at 72 hours after PCI (ρ = 0.23, p = 0.006). CONCLUSIONS: PTX3 had a similar kinetic profile to IL-6, with an early increase and decline, and was statistically significantly correlated with markers of infarct size in STEMI patients post primary PCI. Baseline levels of IL-6 only predicted infarct size at 72 hours post PCI.

Increased mortality from somatic multimorbidity in patients with schizophrenia: a Danish nationwide cohort study.

OBJECTIVE: To investigate the association of single- and multimorbidity with mortality rates in patients with schizophrenia compared to the general population. METHOD: A nationwide cohort study including residents in Denmark between 1995 and 2015. The cohort was dichotomously divided by a diagnosis of schizophrenia. Somatic diseases included infections, cancer, endocrine, neurologic, cardiovascular, respiratory, digestive, skin, musculoskeletal, and urogenital diseases. Hazard ratios (HRs) and population attributable fractions (PAFs) were calculated. RESULTS: The cohort included 30 210 patients with schizophrenia [mean age (SD) = 32.6 (11.4), males = 57.2%], and 5 402 611 from the general population [mean age (SD) = 33.0 (14.5), males = 50.4%]. All number of somatic diseases were associated with an increased mortality in schizophrenia [HR = 16.3 (95% CI = 15.4-17.3) for 1 disease to 21.0 (95% CI = 19.1-23.0) for ≥5 diseases], using the general population with no somatic disease as reference. Across all somatic diseases, patients with schizophrenia showed a HR > 2, compared to the general population, and respiratory (PAF = 9.3%), digestive (PAF = 8.2%), and cardiovascular (PAF = 7.9%) diseases showed largest contributions to death. CONCLUSIONS: Patients with schizophrenia showed higher mortality on all levels of multimorbidity, and a doubled mortality rate across all somatic diseases, compared to the general population. The findings suggest that the clusters and trajectories of symptoms associated with schizophrenia is the main driver of the excess mortality.

Opportunities for shared decision making in kidney transplantation.

Health researchers and policy-makers increasingly urge both patient and clinician engagement in shared decision making (SDM) to promote patient-centered care. Although SDM has been examined in numerous clinical settings, it has received little attention in solid organ transplantation. This paper describes the application of SDM to the kidney transplantation context. Several distinctive features of kidney transplantation present challenges to SDM including fragmented patient-provider relationships, the time-sensitive and unpredictable nature of deceased organ offers, decision-making processes by transplant providers serving as both organ guardians (given the organ scarcity) versus advocates for specific patients seeking transplantation, variable clinical practices and policies among transplant centers, and patients' potentially compromised cognitive status and literacy levels. We describe potential barriers to and opportunities for SDM, and posit that SDM is feasible, warranting encouragement in kidney transplantation. We propose strategies to promote and overcome obstacles to SDM in kidney transplantation. We contend that engagement in SDM can be facilitated by re-organization of clinical care, communication and education of providers and patients.

An alternative temperature-based histamine-sensitisation test for absence of residual pertussis toxin in acellular pertussis vaccines.

As an extension of the BSP076 study (see the article 'Collaborative Study for the Standardisation of the Histamine Sensitizing Test in Mice and the CHO Cell-based Assay for the Residual Toxicity Testing of Acellular Pertussis Vaccines (BSP076)', page 51 of this issue of Pharmeuropa Bio & Scientific Notes), it was decided to publish the following experimental method for the temperature-based histamine-sensitisation test, validated at the SSI (Statens Serum Institut, Denmark), as a working basis for the growth of the method in individual laboratories.

Five additional genes are involved in clavulanic acid biosynthesis in Streptomyces clavuligerus.

An approximately 12.5-kbp region of DNA sequence from beyond the end of the previously described clavulanic acid gene cluster was analyzed and found to encode nine possible open reading frames (ORFs). Involvement of these ORFs in clavulanic acid biosynthesis was assessed by creating mutants with defects in each of the ORFs. orf12 and orf14 had been previously reported to be involved in clavulanic acid biosynthesis. Now five additional ORFs are shown to play a role, since their mutation results in a significant decrease or total absence of clavulanic acid production. Most of these newly described ORFs encode proteins with little similarity to others in the databases, and so their roles in clavulanic acid biosynthesis are unclear. Mutation of two of the ORFs, orf15 and orf16, results in the accumulation of a new metabolite, N-acetylglycylclavaminic acid, in place of clavulanic acid. orf18 and orf19 encode apparent penicillin binding proteins, and while mutations in these genes have minimal effects on clavulanic acid production, their normal roles as cell wall biosynthetic enzymes and as targets for beta-lactam antibiotics, together with their clustered location, suggest that they are part of the clavulanic acid gene cluster.

Prognostic value of left ventricular diastolic function and association with heart rate variability after a first acute myocardial infarction.

OBJECTIVE: To study the prognostic value of left ventricular (LV) diastolic function and its relation with autonomic balance expressed by heart rate variability (HRV) in patients after a first acute myocardial infarction. DESIGN: The study population consisted of 64 consecutive patients with first acute myocardial infarction and 31 control subjects. Long and short term HRV indices were evaluated by 24 hour Holter monitoring, and LV systolic and diastolic function were assessed by two dimensional and Doppler echocardiography before discharge. Patients were divided into two groups: those with restrictive LV filling characteristics (deceleration time 140 ms). RESULTS: Both long and short term HRV indices were significantly reduced in patients with restrictive LV filling compared with the non-restrictive group and control subjects. Mitral deceleration time and isovolumetric relaxation time correlated weakly but significantly with all indices of HRV whereas ejection fraction correlated weakly with the long term HRV indices. The mean follow up time was 14.9 (8.7) months. Multivariate analysis showed that mitral deceleration time (chi(2) = 6.4, p < 0.001) and ejection fraction

Applications of gene replacement technology to Streptomyces clavuligerus strain development for clavulanic acid production.

Cephamycin C production was blocked in wild-type cultures of the clavulanic acid-producing organism Streptomyces clavuligerus by targeted disruption of the gene (lat) encoding lysine epsilon-aminotransferase. Specific production of clavulanic acid increased in the lat mutants derived from the wild-type strain by 2- to 2.5-fold. Similar beneficial effects on clavulanic acid production were noted in previous studies when gene disruption was used to block the production of the non-clavulanic acid clavams produced by S. clavuligerus. Therefore, mutations in lat and in cvm1, a gene involved in clavam production, were introduced into a high-titer industrial strain of S. clavuligerus to create a double mutant with defects in production of both cephamycin C and clavams. Production of both cephamycin C and non-clavulanic acid clavams was eliminated in the double mutant, and clavulanic acid titers increased about 10% relative to those of the parental strain. This represents the first report of the successful use of genetic engineering to eliminate undesirable metabolic pathways in an industrial strain used for the production of an antibiotic important in human medicine.

Serial changes and prognostic implications of a Doppler-derived index of combined left ventricular systolic and diastolic myocardial performance in acute myocardial infarction.

The purpose of this study was to investigate the serial changes and prognostic value of a nongeometric Doppler-derived index of myocardial function that combines systolic and diastolic time intervals of the left ventricle in acute myocardial infarction (AMI). The Doppler index was measured in 60 consecutive patients with AMI and in 30 patients admitted to hospital with suspected but disproved AMI who served as controls. The patients were studied at days 1, 5, 90, and 360 after arrival in the coronary care unit. The index was defined as the sum of isovolumetric contraction time, and isovolumetric relaxation time divided by ejection time was measured from mitral inflow and left ventricular outflow Doppler velocity profiles. The index was significantly higher in patients with AMI than in control subjects at days 1 and 360 (day 1, 0.58 +/- 0.09 vs 0.41 +/- 0.08, p <0.0001; day 360, 0.50 +/- 0.09 vs 0.39 +/- 0.07, p <0.01, respectively). The index decreased significantly in patients with AMI during follow-up (p <0.01). The index was significantly higher in patients who developed congestive heart failure or died compared with survivors who were free of congestive heart failure (day 1, 0.63 +/- 0.10 vs 0.53 +/- 0.10, p <0.01; day 360, 0.56 +/- 0.08 vs 0.48 +/- 0.10, p <0.01, respectively). During 20.2 +/- 8.5 months' follow-up, 10 patients died of cardiac causes and 13 developed congestive heart failure. Univariate analyses demonstrated that the Doppler index > or =0.60 (chi-square 8.3, p <0.0001), deceleration time < or =140 ms (chi-square 8.5, p <0.0001), ejection fraction < or =0.40% (chi-square 3.3, p <0.005), anterior wall AMI (chi-square 3.2, p <0.01), and age (chi-square 1.06/ year increase, p <0.01) were significant predictors of outcome. Multivariate stepwise analysis showed that the index < or =0.60 (chi-square 3.4, p <0.05), deceleration time < or =140 ms (chi-square 4.2, p <0.02), and age (chi-square 1.06/year increase, p <0.02) were independent predictors of outcome. The Doppler index reflects severity of left ventricular function and has incremental prognostic value in patients with AMI.

Value of the Doppler index of myocardial performance in the early phase of acute myocardial infarction.

Prospective assessment of a nongeometric Doppler-derived index of combined systolic and diastolic myocardial performance was performed in 64 patients with acute myocardial infarction (MI) within 1 hour after their arrival to the hospital and in 39 age-matched healthy subjects. The index is defined as the sum of isovolumetric contraction time and relaxation time divided by ejection time, and is obtained by Doppler measurement from the mitral inflow and left ventricular outflow velocity-time intervals. The index was significantly higher in patients with MI compared with healthy subjects (P <.0001). In patients with MI and in-hospital congestive heart failure (CHF), the index was significantly higher compared with patients without CHF. In a multivariate regression analysis, the index >0.45 was the strongest independent predictor of the development of CHF. This simply obtained nongeometric Doppler index, assessed in the early phase of MI, detected and graded left ventricular dysfunction and identified patients at risk for the development of CHF.

Improvement of exercise capacity and left ventricular diastolic function with metoprolol XL after acute myocardial infarction.

BACKGROUND: Left ventricular (LV) diastolic function predicts and correlates with exercise capacity. Beta-blockers improve exercise capacity and LV diastolic function in patients with severe LV systolic dysfunction in dilated cardiomyopathy. However, information on the effect of metoprolol XL on exercise capacity in relation to LV diastolic function in patients with mild to moderate LV systolic dysfunction after acute myocardial infarction is limited. METHODS: In a randomized, double-blind, placebo-controlled study of 77 patients, a subgroup of 59 patients with mild to moderate LV systolic dysfunction after acute myocardial infarction were given metoprolol XL (n = 29) or placebo (n = 30). The effects of metoprolol XL on exercise capacity in relation to effects on LV diastolic filling were studied. Two-dimensional Doppler echocardiography and maximal symptom limited bicycle test were performed on days 5 through 7 and after 3 months. RESULTS: Maximal exercise capacity increased in the metoprolol XL group (124 +/- 30 W vs 135 +/- 29 W) compared with placebo (125 +/- 31 W vs 126 +/- 34 W) (P <.01). E/A ratio decreased, A peak velocity increased, reverse pulmonary flow decreased, and deceleration time was significantly prolonged in the metoprolol XL group. A significant correlation was found between the changes of deceleration time (metoprolol XL: rho = 0.69, P <.0001; placebo: rho = 0.31, P = not significant) and A peak velocity (metoprolol XL: rho = 0.71, P <.0001; placebo: rho = -0.15, not significant) in relation to changes of exercise capacity. CONCLUSION: Metoprolol XL increases exercise capacity after 3 months, and this change seems related to improvement of LV diastolic filling after acute myocardial infarction.

Structure-based design guides the improved efficacy of deacylation transition state analogue inhibitors of TEM-1 beta-Lactamase(,).

Transition state analogue boronic acid inhibitors mimicking the structures and interactions of good penicillin substrates for the TEM-1 beta-lactamase of Escherchia coli were designed using graphic analyses based on the enzyme's 1.7 A crystallographic structure. The synthesis of two of these transition state analogues, (1R)-1-phenylacetamido-2-(3-carboxyphenyl)ethylboronic acid (1) and (1R)-1-acetamido-2-(3-carboxy-2-hydroxyphenyl)ethylboronic acid (2), is reported. Kinetic measurements show that, as designed, compounds 1 and 2 are highly effective deacylation transition state analogue inhibitors of TEM-1 beta-lactamase, with inhibition constants of 5.9 and 13 nM, respectively. These values identify them as among the most potent competitive inhibitors yet reported for a beta-lactamase. The best inhibitor of the current series was (1R)-1-phenylacetamido-2-(3-carboxyphenyl)ethylboronic acid (1, K(I) = 5.9 nM), which resembles most closely the best known substrate of TEM-1, benzylpenicillin (penicillin G). The high-resolution crystallographic structures of these two inhibitors covalently bound to TEM-1 are also described. In addition to verifying the design features, these two structures show interesting and unanticipated changes in the active site area, including strong hydrogen bond formation, water displacement, and rearrangement of side chains. The structures provide new insights into the further design of this potent class of beta-lactamase inhibitors.

Mechanisms associated with methiocarb resistance in Frankliniella occidentalis (Thysanoptera: Thripidae).

Biochemical mechanisms associated with methiocarb resistance were examined in laboratory-selected and field populations of the western flower thrips, Frankliniella occidentalis (Pergande). Seven populations were examined and they differed in their susceptibility to methiocarb by 30 times. Including the synergists piperonyl butoxide, a cytochrome P-450 monooxygenase inhibitor, or S,S,S-tributylphosphorotrithioate, an esterase inhibitor, in the methiocarb bioassays partially suppressed resistance in the most resistant populations. In vitro assays of general esterase, glutathione S-transferase, and acetylcholinesterase activities showed increased activity in some of the resistant populations and increased activity of the enzymes after methiocarb selection on one of the populations. Assays of acetylcholinesterase sensitivity to inhibition by methiocarb, dichlorvos, and eserine suggested insensitive acetylcholinesterase in two of the resistant populations. These results indicate that methiocarb resistance in F. occidentalis was polyfactorial and involved detoxification and altered target site. None of the biochemical assays showed interpopulation enzymatic differences strongly correlated with the level of methiocarb resistance. The possibilities for developing rapid biochemical diagnostic assays to detect methiocarb resistance in F. occidentalis are discussed.

Relationship between serum amino-terminal propeptide of type III procollagen and changes of left ventricular function after acute myocardial infarction.

BACKGROUND: The amino-terminal propeptide of type III procollagen (PIIINP) is a marker of type III collagen synthesis, which has previously been shown to correlate with infarct size in nonthrombolyzed myocardial infarction (MI) and to provide prognostic information after MI. METHODS AND RESULTS: The relationship between PIIINP and changes of left ventricular (LV) function was studied in 47 consecutive patients with first acute MI and 16 control subjects. Serum PIIINP analysis was measured daily during hospitalization and on days 90, 180, and 360. LV function was assessed by echocardiography on days 1, 5, 90, and 360. Patients with MI were stratified according to their serum PIIINP value at day 4 (group A, 5.0 microg/L). On arrival, LV function and size were comparable between groups A (n=31) and B (n=16). LV ejection fraction, initially depressed (day 1: group A, 47+/-7% versus group B, 47+/-8%; P=NS), increased significantly in group A (day 360: 54+/-8%, P<0.001) but was unchanged in group B (day 360: 43+/-8%, P=NS). LV volumes increased significantly in group B (P<0. 05) but not in group A. Furthermore, patients in group B developed signs of restrictive LV diastolic filling. Multivariate regression analysis identified PIIINP >5.0 microg/L and deceleration

The Bloch equations in high-gradient magnetic resonance force microscopy: theory and experiment.

We report theory and observations of paramagnetic resonance in a measured field gradient of 44,000 T per meter by the technique of magnetic resonance force microscopy (MRFM). Resonance was induced in a dilute solid solution of diphenylpicrylhydrazyl in polystyrene at 77 and 10 K by an amplitude-modulated microwave field. This modulated the force between resonant sample spins and a micrometer-scale SmCo magnetic tip on a force microscope cantilever. The force signals were typically of order 10 fN, and were detected above a thermal noise floor of 80 aN per root hertz at 10 K, equivalent to a magnetic moment noise of 200 micro(B) per root hertz of bandwidth. Resonance saturation was readily observed. Starting with the Bloch equations, we derived simple analytic expressions for the predicted cantilever signal amplitudes and T(1)-dependent phase lags, valid at low microwave power levels. For power levels below saturation, the data were in good agreement with the Bloch equation predictions, while above saturation the measured force increased more slowly with power than predicted. Several ESR mechanisms which might lead to non-Bloch dynamics in the MRFM environment are reviewed. Spin-relaxation mechanisms are also reviewed. A detailed description of the experimental apparatus is offered.

Enzymes catalyzing the early steps of clavulanic acid biosynthesis are encoded by two sets of paralogous genes in Streptomyces clavuligerus.

Genes encoding the proteins required for clavulanic acid biosynthesis and for cephamycin biosynthesis are grouped into a "supercluster" in Streptomyces clavuligerus. Nine open reading frames (ORFs) associated with clavulanic acid biosynthesis were located in a 15-kb segment of the supercluster, including six ORFs encoding known biosynthetic enzymes or regulatory proteins, two ORFs that have been reported previously but whose involvement in clavulanic acid biosynthesis is unclear, and one ORF not previously reported. Evidence for the involvement of these ORFs in clavulanic acid production was obtained by generating mutants and showing that all were defective for clavulanic acid production when grown on starch asparagine medium. However, when five of the nine mutants, including mutants defective in known clavulanic acid biosynthetic enzymes, were grown in a soy-based medium, clavulanic acid-producing ability was restored. This ability to produce clavulanic acid when seemingly essential biosynthetic enzymes have been mutated suggests that paralogous genes encoding functionally equivalent proteins exist for each of the five genes but that these paralogues are expressed only in the soy-based medium. The five genes that have paralogues encode proteins involved in the early steps of the pathway common to the biosynthesis of both clavulanic acid and the other clavam metabolites produced by this organism. No evidence was seen for paralogues of the four remaining genes involved in late, clavulanic acid-specific steps in the pathway.

Early cephamycin biosynthetic genes are expressed from a polycistronic transcript in Streptomyces clavuligerus.

A polycistronic transcript that is initiated at the lat promoter has been implicated in the expression of the genes involved in early steps of cephamycin C biosynthesis in Streptomyces clavuligerus. pcbC is also expressed as a monocistronic transcript from its own promoter. However, an alternative interpretation involving expression via three separate yet interdependent transcripts has also been proposed. To distinguish between these possibilities, mutants lacking the lat promoter and containing a transcription terminator within the lat gene (Deltalat::tsr/term mutants) were created. This mutation eliminated the production of lysine-epsilon-aminotransferase (the lat gene product) but also affected the expression of downstream genes, indicating an operon arrangement. Production of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS) (the pcbAB gene product) was eliminated in Deltalat::tsr/term mutants, while production of isopenicillin N synthase (IPNS) (the pcbC gene product) was greatly reduced. The provision of alpha-aminoadipate to the Deltalat::tsr/term mutants, either via exogenous feeding or via lat gene complementation, did not restore production of ACVS or IPNS. Analysis of RNA isolated from the Deltalat::tsr/term mutants confirmed that the polycistronic transcript was absent but also indicated that monocistronic pcbC transcript levels were greatly decreased. In contrast, Deltalat mutants created by in-frame internal deletion of lat maintained the polycistronic transcript and allowed production of wild-type levels of both ACVS and IPNS.

Host Plant Effects on Activities of Detoxification Enzymes and Insecticide Tolerance in Western Flower Thrips, Frankliniella occidentalis (Insecta).

The polyphagous western flower thrips, Frankliniella occidentalis, is a severe pest of horticultural crops. Individuals from a laboratory population adapted to bean plants were transferred to new host plants, sweet pepper and chrysanthemum, to establish two new populations. The thrips appeared to perform poorly on the new host plants, as the total protein content of individual adults was lowered in the new populations. The specific activities of two insect detoxification enzyme systems, esterases and glutathione S-transferases, were assayed in vitro in the three populations. Host plant shifts had no effect on the level of general esterase activity to α-naphthyl acetate and only a minor effect on the level of glutathione S-transferase activity to 1-chloro-2,4-dinitrobenzene. The new population on pepper plants had slightly lowered glutathione S-transferase activity. The level of tolerance to the insecticide, methiocarb, was not affected by culturing the thrips on new host plants, nor was the total activity per individual of acetylcholinesterase, the target-site enzyme for methiocarb.