Effect of conjugated bile salts on antibiotic susceptibility of bile salt-tolerant Lactobacillus and Bifidobacterium isolates.

Virtually every antibiotic may cause in vivo alterations in the number, level, and composition of the indigenous microbiotae. The degree to which the microbiotae are disturbed depends on many factors. Although bile may augment antibiotic activity, studies on the effect of bile on the antibiotic susceptibility of indigenous and exogenous probiotic microorganisms are lacking. It was against this background that the antibiotic susceptibility of 37 bile salt-tolerant Lactobacillus and 11 Bifidobacterium isolates from human and other sources was determined in the presence of 0.5% wt/wt oxgall (conjugated bile salts). Oxgall did not affect the intrinsic resistance of lactobacilli to metronidazole (5 microg), vancomycin (30 microg), and cotrimoxazole (25 microg), whereas it resulted in a complete loss of resistance to polymyxin B (300 microg) and the aminoglycosides gentamicin (10 microg), kanamycin (30 microg), and streptomycin (10 microg) for most strains studied (P < 0.001). Oxgall did not affect the intrinsic resistance of bifidobacteria to metronidazole and vancomycin, whereas polymyxin B and co-trimoxazole resistance was diminished (P < 0.05) and aminoglycoside resistance was lost (P < 0.001). Seven lactobacilli, but no bifidobacteria strain, showed unaltered intrinsic antibiotic resistance profiles in the presence of oxgall. Oxgall affected the extrinsic susceptibility of lactobacilli and bifidobacteria to penicillin G (10 microg), ampicillin (10 microg), tetracycline (30 microg), chloramphenicol (30 microg), erythromycin (15 microg), and rifampicin (5 microg) in a source- and strain-dependent manner. Human strain-drug combinations of lactobacilli (P < 0.05) and bifidobacteria (P < 0.01) were more likely to show no change or decreased susceptibility compared with other strain-drug combinations. The antimicrobial activity spectra of polymyxin B and the aminoglycosides should not be considered limited to gram-negative bacteria but extended to include gram-positive genera of the indigenous and transiting microbiotae in the presence of conjugated bile salts. Those lactobacilli (7 of 37) that show unaltered intrinsic and diminished extrinsic antibiotic susceptibility in the presence of oxgall may possess greater upper gastrointestinal tract transit tolerance in the presence of antibiotics

Antibiotic susceptibility of potentially probiotic Lactobacillus species.

In recent years, the time-honored reputation of lactobacilli as promoters of gastrointestinal and female urogenital health has been qualified. This has occurred due to a rare association with human infection in the presence of certain predisposing factors and their potential to act as a source of undesirable antibiotic resistance determinants to other members of the indigenous microbiota. This necessitates greater caution in their selection for use in microbial adjunct nutrition and disease management (prophylaxis and therapy). It was against this background that 46 Lactobacillus strains from human and dairy sources were assayed for susceptibility to 44 antibiotics. All strains were resistant to a group of 14 antibiotics, which included inhibitors of cell wall synthesis (cefoxitin [30 microg] and aztreonam [30 microg]), protein synthesis (amikacin [30 microg], gentamicin [10 microg], kanamycin [30 microg], and streptomycin [10 microg]), nucleic acid synthesis (norfloxacin [10 microg], nalidixic acid [30 microg], sulphamethoxazole [100 microg], trimethoprim [5 microg], co-trimoxazole [25 microg], and metronidazole [5 microg]), and cytoplasmic membrane function (polymyxin B [300 microg] and colistin sulphate [10 microg]). All strains were susceptible to tetracycline (30 microg), chloramphenicol (30 microg), and rifampicin (5 microg). Four human strains and one dairy strain exhibited atypical resistance to a penicillin, bacitracin (10 microg), and/or nitrofurantoin (300 microg). One human strain was also resistant to erythromycin (15 microg) and clindamycin (2 microg). These resistances may have been acquired due to antibiotic exposure in vivo, but conclusive evidence is lacking in this regard. Seven microorganism-drug combinations were evaluated for beta-lactamase activity using synergy and nitrocefin tests. The absence of activity suggested that cell wall impermeability appeared responsible for beta-lactam resistance. The occurrence of a minority of lactobacilli with undesirable, atypical resistance to certain antibiotics demonstrates that not all strains are suitable for use as probiotics or bacteriotherapeutic agents. The natural resistance of lactobacilli to a wide range of clinically important antibiotics may enable the development of antibiotic/probiotic combination therapies for such conditions as diarrhea, female urogenital tract infection, and infective endocarditis

Exploring the use of a modified high-temperature, short-time continuous heat exchanger with extended holding time (HTST-EHT) for thermal inactivation of trypsin following selective enzymatic hydrolysis of the ß- lactoglobulin fraction in whey protein isolate

peer-reviewedTryptic hydrolysis of whey protein isolate under specific incubation conditions including a relatively high enzyme:substrate (E:S) ratio of 1:10 is known to preferentially hydrolyse ß-lactoglobulin (ß-LG), while retaining the other major whey protein fraction, i.e., x-lactalbumin(x-LA) mainly intact. An objective of the present work was to explore the e ects of reducing E:S (1:10 1:30, 1:50, 1:100) on the selective hydrolysis of ß-LG by trypsin at pH 8.5 and 25 °C in a 5% (w/v) WPI solution during incubation periods ranging from 1 to 7 h. In addition, the use of a pilot-scale continuous high-temperature, short-time (HTST) heat exchanger with an extended holding time (EHT) of 5 min as a means of inactivating trypsin to terminate hydrolysis was compared with laboratory-based acidification to <pH 3 by the addition of HCl, and batch sample heating in a water bath at 85 °C. An E:S of 1:10 resulted in 100% and 30% of ßLG and x-LA hydrolysis, respectively, after 3 h, while an E:S reduction to 1:30 and 1:50 led >90% ß-LG hydrolysis after respective incubation periods of 4 and 6 h, with <5% hydrolysis of x-LA in the case of 1:50. Continuous HTST-EHT treatment was shown to be an e ective inactivation process allowing for the maintenance of substrate selectivity. However, HTST-EHT heating resulted in protein aggregation, which negatively impacts the downstream recovery of intact -LA. An optimum E:S was determined to be 1:50, with an incubation time ranging from 3 h to 7 h leading to 90% ß-LG hydrolysis and minimal degradation of x-LA. Alternative batch heating by means of a water bath to inactivate trypsin caused considerable digestion of x-LA, while acidification to <pH 3.0 restricted subsequent functional applications of the protein

Using Bioenergetics and Radar-Derived Bird Abundance to Assess the Impact of a Blackbird Roost on Seasonal Sunflower Damage

Methods aimed at reducing avian damage to agricultural crops are routinely implemented in situations where efficacy can be assessed by quantifying blackbird (Icteridae) abundance relative to environmental variables and extrapolating to ensuing crop damage. Concomitantly, Weather Surveillance Radar (WSR) data may have potential to enhance crop damage mitigation through improved monitoring of nuisance wildlife populations. We used WSR to derive daily abundance estimates of blackbirds at a fall roost in North Dakota, USA from 2012 to 2019. We integrated these estimates with previously developed bioenergetics-economic models to estimate local sunflower (Helianthus annuus) damage. The greatest losses usually occurred during a brief period in October, when peak blackbird abundance coincided with large percentages (\u3e50%) of mature but unharvested sunflower fields. Most sunflower fields were harvested later than peak blackbird abundance (360,000–1,120,000 birds) and maximum daily damages ($900–$2,000 USD per day). This seasonal trend suggests advancing harvest time as a strategy to avoid the greatest losses in yield (up to $1,800 in savings at this 1 roost), which may be attainable by earlier planting of early-maturing crop varieties or crop desiccation

Survey of research approaches utilised in the scholarship of teaching and learning publications

The Scholarship of Teaching and Learning (SoTL) has been described as the fastest growing academic development movement in higher education. As this field of inquiry matures, there is a need to understand how SoTL research is conducted. The purpose of our study was to inform this debate by investigating research approaches used in SoTL publications. We analysed 223 empirical research studies published from 2012 to 2014 in three explicitly focused SoTL journals. We classified the studies as either qualitative, quantitative, or mixed methods using an analytical framework devised from existing literature on research methods. We found that the use of the three research designs was fairly evenly distributed across the papers examined: qualitative (37.2%), quantitative (29.6%), and mixed methods (33.2%). However, there was an over-reliance on data collection from a single source in 83.9% of papers analysed, and this source was primarily students. There was some, but limited, evidence of the use of triangulation through the use of multiple data collection instruments (e.g. survey, assessment tasks, grade databases). Similarly, only one-third of publications classified as mixed methods integrated the analysis and interpretation of the qualitative and quantitative data equally within the study. We conclude that current SoTL research is characterised by methodological pluralism but could be advanced through inclusion of more diverse approaches, such as close reading, and adoption of strategies known to enhance the quality of research, for example, triangulation and visual representation

Ethics roundtable: Using new, expensive drugs

Costly genetically engineered therapies, which threaten to cripple the health care industry economy and undermine the common good if applied indiscriminately, loom on the horizon. The spectrum of applicable candidates include moribund nursing home patients at the end of life. They will be fair game for therapy that will ultimately send them back to nursing homes to return later with the same condition. 'Quality of life' assessments that limit patient autonomy may be forced as a result. Discussants from South Africa, New Zealand, and the USA suggest methods to deal with this issue in a just and ethical framework

Synthesis and Crystal Structure of Tetrachloro (1,10-phenanthroline) platinum (IV)

We report the crystal structure determination of tetrachloro( l,10-phenan­throline)platinum(IV). X-ray data indicate there is little steric repulsion between the cx.-hydrogens on the phenanthroline ligand and the chloride ligands in the equatorial plane

Focused Exhumation Along Megathrust Splay Faults in Prince William Sound, Alaska

Megathrust splay faults are a common feature of accretionary prisms and can be important for generating tsunamis during some subduction zone earthquakes. Here we provide new evidence from Alaska that megathrust splay faults have been conduits for focused exhumation in the last 5 Ma. In most of central Prince William Sound, published and new low-temperature thermochronology data indicate little to no permanent rock uplift over tens of thousands of earthquake cycles. However, in southern Prince William Sound on Montague Island, apatite (U–Th)/He ages are as young as 1.1 Ma indicating focused and rapid rock uplift. Montague Island lies in the hanging wall of the Patton Bay megathrust splay fault system, which ruptured during the 1964 M9.2 earthquake and produced ∼9 m of vertical uplift. Recent geochronology and thermochronology studies show rapid exhumation within the last 5 Ma in a pattern similar to the coseismic uplift in the 1964 earthquake, demonstrating that splay fault slip is a long term (3–5 my) phenomena. The region of slower exhumation correlates with rocks that are older and metamorphosed and constitute a mechanically strong backstop. The region of rapid exhumation consists of much younger and weakly metamorphosed rocks, which we infer are mechanically weak. The region of rapid exhumation is separated from the region of slow exhumation by the newly identified Montague Strait Fault. New sparker high-resolution bathymetry, seismic reflection profiles, and a 2012 Mw4.8 earthquake show this feature as a 75-km-long high-angle active normal fault. There are numerous smaller active normal(?) faults in the region between the Montague Strait Fault and the splay faults. We interpret this hanging wall extension as developing between the rapidly uplifting sliver of younger and weaker rocks on Montague Island from the essentially fixed region to the north. Deep seismic reflection profiles show the splay faults root into the subduction megathrust where there is probable underplating. Thus the exhumation and extension in the hanging wall are likely driven by underplating along the megathrust décollement, thickening in the overriding plate and a change in rheology at the Montague Strait Fault to form a structural backstop. A comparison with other megathrust splay faults around the world shows they have significant variability in their characteristics, and the conditions for their formation are not particularly unique

Statins and Exercise Training Response in Heart Failure Patients: Insights From HF-ACTION.

OBJECTIVES: The aim of this study was to assess for a treatment interaction between statin use and exercise training (ET) response. BACKGROUND: Recent data suggest that statins may attenuate ET response, but limited data exist in patients with heart failure (HF). METHODS: HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) was a randomized trial of 2,331 patients with chronic HF with ejection fraction ≤35% who were randomized to usual care with or without ET. We evaluated whether there was a treatment interaction between statins and ET response for the change in quality of life and aerobic capacity (peak oxygen consumption and 6-min walk distance) from baseline to 3 months. We also assessed for a treatment interaction among atorvastatin, simvastatin, and pravastatin and change in these endpoints with ET. Multiple linear regression analyses were performed for each endpoint, adjusting for baseline covariates. RESULTS: Of 2,331 patients in the HF-ACTION trial, 1,353 (58%) were prescribed statins at baseline. Patients treated with statins were more likely to be older men with ischemic HF etiology but had similar use of renin angiotensin system blockers and beta-blockers. There was no evidence of a treatment interaction between statin use and ET on changes in quality of life or exercise capacity, nor was there evidence of differential association between statin type and ET response for these endpoints (all p values \u3e0.05). CONCLUSIONS: In a large chronic HF cohort, there was no evidence of a treatment interaction between statin use and short-term change in aerobic capacity and quality of life with ET. These findings contrast with recent reports of an attenuation in ET response with statins in a different population, highlighting the need for future prospective studies. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437)