Overall, fluoroquinolone resistance was relatively low. However, receipt of fluoroquinolones for more than 10 days, particularly more than 60 days before tuberculosis diagnosis, was associated with a high risk of fluoroquinolone-resistant tuberculosis.

MGIT 960, MODS and NRA are sensitive and specific and more rapid than PM for identifying fluoroquinolone resistance in M. tuberculosis. Ofloxacin resistance was associated with cross-resistance to ciprofloxacin, levofloxacin and moxifloxacin.

Thermal regimes can diverge considerably across the geographic range of a species, and accordingly, populations can vary in their response to changing environmental conditions. Both local adaptation and acclimatization are important mechanisms for ectotherms to maintain homeostasis as environments become thermally stressful, which organisms often experience at their geographic range limits. The spatial spread of the gypsy moth (Lymantria dispar L.) (Lepidoptera: Erebidae) after introduction to North America provides an exemplary system for studying population variation in physiological traits given the gradient of climates encompassed by its current invasive range. This study quantifies differences in resting metabolic rate (RMR) across temperature for four populations of gypsy moth, two from the northern and two from southern regions of their introduced range in North America. Gypsy moth larvae were reared at high and low thermal regimes, and then metabolic activity was monitored at four temperatures using stop-flow respirometry to test for an acclimation response. For all populations, there was a significant increase in RMR as respirometry test temperature increased. Contrary to our expectations, we did not find evidence for metabolic adaptation to colder environments based on our comparisons between northern and southern populations. We also found no evidence for an acclimation response of RMR to rearing temperature for three of the four pairwise comparisons examined. Understanding the thermal sensitivity of metabolic rate in gypsy moth, and understanding the potential for changes in physiology at range extremes, is critical for estimating continued spatial spread of this invasive species both under current and potential future climatic constraints.

Mucin-type O-glycosylation is an essential post-translational modification required for protein secretion, extracellular matrix formation and organ growth. O-glycosylation is initiated by a large family of enzymes (GALNTs in mammals and PGANTs in Drosophila) that catalyze the addition of N-acetylgalactosamine (GalNAc) onto the hydroxyl groups of serines or threonines in protein substrates. These enzymes contain 2 functional domains; a catalytic domain and a C-terminal ricin-like lectin domain comprised of 3 potential GalNAc recognition repeats termed α, β and γ. The catalytic domain is responsible for binding donor and acceptor substrates and catalyzing transfer of GalNAc, while the lectin domain recognizes more distant extant GalNAc on previously glycosylated substrates. We previously demonstrated a novel role for the α repeat of lectin domain in influencing charged peptide preferences. Here, we further interrogate how the differentially spliced α repeat of the PGANT9A and PGANT9B O-glycosyltransferases confers distinct preferences for a variety of endogenous substrates. Through biochemical analyses and in silico modeling using preferred substrates, we find that a combination of charged residues within the α repeat and charged residues in the flexible gating loop of the catalytic domain distinctively influence the peptide substrate preferences of each splice variant. Moreover, PGANT9A and PGANT9B also display unique glycopeptide preferences. These data illustrate how changes within the non-catalytic lectin domain can alter the recognition of both peptide and glycopeptide substrates. Overall, our results elucidate a novel mechanism for modulating substrate preferences of O-glycosyltransferases via alternative splicing within specific subregions of functional domains.

SUMMARYSETTING-Fluoroquinolone (FQ) exposure before tuberculosis (TB) diagnosis is common, but its effect on outcomes, including mortality, is unclear. DESIGN-Among TB patients reported to the Tennessee Department of Health from 2007 to2009, we assessed FQ exposure within 6 months before TB diagnosis. The primary outcome was the combined endpoint of death at the time of TB diagnosis and during anti-tuberculosis treatment.RESULTS-Among 609 TB cases, 214 (35%) received FQs within 6 months before TB diagnosis. A total of 71 (12%) persons died; 10 (2%) were dead at TB diagnosis and 61 (10%) died during anti-tuberculosis treatment. In multivariable logistic regression analysis, factors independently associated with death were older age (OR 1.05 per year, 95%CI 1.04-1.07), human immunodeficiency virus infection (OR 8.08,, US birth (OR 3.03, 95%CI 1.03-9.09), and any FQ exposure before TB diagnosis (OR 1.82,. Persons with FQ exposure before TB diagnosis were more likely to have culture-and smear-positive disease than unexposed persons.CONCLUSIONS-Among this patient population, FQ exposure before TB diagnosis was associated with an increased risk of death. These findings underscore the need for cautious use of FQs in persons with possible TB.Keywords drug-susceptible TB; drug resistance; mortality Despite a Decrease in worldwide incidence since 2002, tuberculosis (TB) continues to be a major cause of mortality worldwide; it is estimated that 1.45 million persons died from TB in 2010. The use of FQs prior to TB diagnosis has been associated with an increased risk of FQ resistance [10][11][12] and delays in diagnosis and treatment of pulmonary TB. [13][14][15][16][17] One retrospective study in a TB-endemic area found that FQ exposure before TB diagnosis was associated with increased mortality. 14 We sought to clarify the association between FQ exposure before TB diagnosis and mortality in an area of low TB incidence using a prospective cohort with both in-and out-patient FQ exposure data. METHODSWe performed a prospective cohort study among patients with newly diagnosed TB reported to the Tennessee Department of Health (DoH) from January 2007 to December 2009. Patients from the cohort were included if they had an assessment for possible FQ exposure starting 6 months before TB diagnosis from at least one of four sources. An FQ exposure assessment survey was completed by Tennessee DoH staff who questioned TB patients regarding receipt of FQs. An in-home questionnaire recorded data from face-to-face interviews of patients with culture-positive TB conducted by research study staff regarding patient recall of FQ prescriptions. Research study staff reviewed clinic and hospital records to assess details of FQ prescriptions among culture-positive patients who gave consent and for any culture-positive patients who were dead at diagnosis, died during treatment or died after completion of anti-tuberculosis treatment. For each of the four sources of FQ exposure data, the names of specific FQs prescribed during the 6 months preceding...

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Mucin‐type O‐glycosylation is an essential post‐translational modification that is required for secretion, extracellular matrix composition and organ growth. O‐glycosylation is initiated by a large family of enzymes (GalNAcTs in mammals and PGANTs in Drosophila) that catalyze the addition of the sugar N‐acetylgalactosamine (GalNAc), onto the hydroxyl groups of serines or threonines in protein substrates. These enzymes have distinct domains, including the catalytic domain and the C‐terminal ricin‐like lectin domain. The catalytic domain is responsible for binding donor and acceptor substrates and catalyzing the transfer of GalNAc, while the lectin domain is thought to recognize extant GalNAc on previously glycosylated substrates to position the catalytic domain for further glycosylation of unmodified serines and threonines. Previous work from our group has demonstrated that one member of this family in Drosophila undergoes differential splicing within the lectin domain, leading to variants that contain either a positively or negatively charged subdomain. Interestingly, while this splicing event affects only a subdomain of the lectin region, we find that it influences peptide specificity. We demonstrate that each charged enzyme variant has a preference for oppositely charged peptide substrates, and that this preference can be predictably altered by altering peptide charge. We further show that the expression of each splice variant is associated with the expression of appropriately charged mucins in secretory tissues of Drosophila, suggesting that differential splicing may be employed in vivo to ensure O‐glycosylation of highly charged substrates. Our results elucidate a mechanism for modulating substrate preferences of O‐glycosyltransferases based on the needs of the cell through alternative splicing within a specific subregion of the non‐catalytic domain.

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