Summer 1978

Nature of the Organic Coating on Sand Grains of Nonwettable Golf Greens (page 3) Massachusetts Turfgrass Winter Injury (6) Investigation and Treatment of Localized Dry Spots on Sand Golf Greens (8) A Recreation Renaissance (15) UMass Turfgrass Research Fund (20

The Hydrodynamics Laboratory of the California Institute of Technology

This paper presents a description of the Hydrodynamics Laboratory and its principal pieces of equipment that have been developed during the last five years. The field of investigations to be undertaken by the Laboratory is presented in general terms

High Glucose-enhanced Acetylcholine Stimulated CGMP Masks Impaired Vascular Reactivity in Tail Arteries from Short-Term Hyperglycemic Rats

Impaired vascular endothelium-dependent relaxation and augmented contractile responses have been reported in several models of long-term hyperglycemia. However, the effects of short-term ambient hyperglycemia are poorly understood. Since oxidative stress has been implicated as a contributor to impaired vascular function, we investigated the following

Isotopic Signature of Massive, Buried Ice in Eastern Taylor Valley, Antarctica: Implications for Its Origin

The coastal regions of the McMurdo Dry Valleys, Antarctica, contain deposits of the Ross Sea Drift, sedimentary material left from the Ross Sea ice sheet from the advance of the West Antarctic ice sheet during the Last Glacial Maximum. Much of this deposit is ice-cored, but data on the stable isotopic composition of water from this ice, which may contain a valuable climate archive, are sparse or incomplete. Widespread thermokarstic ground subsidence in this “coastal thaw zone” of the McMurdo Dry Valleys suggests that these potential records are rapidly being lost due to the melting of ground ice and permafrost. We collected samples of massive buried ice from the Ross Sea Drift in eastern Taylor Valley for δ18O-H2O and δ2H-H2O and measured a broad range of values (δ18O = −27.7 to −37.3 ‰; δ2H = −210 to −295 ‰). These buried ice deposits do not show evidence of alteration through sublimation or evaporation, plot along the local meteoric water line, and have values that indicate ice deposition under a colder climate than present conditions. We propose that this ice was sourced from the Ross Sea ice sheet during the Last Glacial Maximum and contains a valuable and accessible climate record

Unexpected distribution of the fluoroquinolone-resistance gene qnrB in Escherichia coli isolates from different human and poultry origins in Ecuador

Fluoroquinolone resistance can be conferred through chromosomal mutations or by the acquisition of plasmids carrying genes such as the quinolone resistance gene (qnr). In this study, 3,309 strains of commensal Escherichia coli were isolated in Ecuador from: (i) humans and chickens in a rural northern coastal area (n = 2368, 71.5%) and (ii) chickens from an industrial poultry operation (n = 827, 25%). In addition, 114 fluoroquinolone-resistant strains from patients with urinary tract infections who were treated at three urban hospitals in Quito, Ecuador were analyzed. All of the isolates were subjected to antibiotic susceptibility screening. Fluoroquinolone-resistant isolates (FRIs) were then screened for the presence of qnrB genes. A significantly higher phenotypic resistance to fluoroquinolones was determined in E. coli strains from chickens in both the rural area (22%) and the industrial operation (10%) than in strains isolated from humans in the rural communities (3%). However, the rates of qnrB genes in E. coli isolates from healthy humans in the rural communities (11 of 35 isolates, 31%) was higher than in chickens from either the industrial operations (3 of 81 isolates, 6%) or the rural communities (7 of 251 isolates, 2.8%). The occurrence of qnrB genes in human FRIs obtained from urban hospitals was low (1 of 114 isolates, 0.9%). These results suggested that the qnrB gene is more widely distributed in rural settings, where antibiotic usage is low, than in urban hospitals and industrial poultry operations. The role of qnrB in clinical resistance to fluoroquinolones is thus far unknown. [Int Microbiol 2015; 18(2):85-90]Keywords: Escherichia coli · gene qnrB · quinolone resistance · urban hospitals · industral poultry operation

Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity

Ice-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited to investigate environmental and spatial influences on bacterial community structure. Water tracks are annually wetted habitats in the cold-arid soils of Antarctica that form briefly each summer with moisture sourced from snow melt, ground ice thaw, and atmospheric deposition via deliquescence and vapor flow into brines. Compared to neighboring arid soils, water tracks are highly saline and relatively moist habitats. They represent a considerable area (&sim;5&ndash;10 km2) of the Dry Valley terrestrial ecosystem, an area that is expected to increase with ongoing climate change. The goal of this study was to determine how variation in the environmental conditions of water tracks influences the composition and diversity of microbial communities. We found significant differences in microbial community composition between on- and off-water track samples, and across two distinct locations. Of the tested environmental variables, soil salinity was the best predictor of community composition, with members of the Bacteroidetes phylum being relatively more abundant at higher salinities and the Actinobacteria phylum showing the opposite pattern. There was also a significant, inverse relationship between salinity and bacterial diversity. Our results suggest water track formation significantly alters dry soil microbial communities, likely influencing subsequent ecosystem functioning. We highlight how Dry Valley water tracks could be a useful model system for understanding the potential habitability of transiently wetted environments found on the surface of Mars. &nbsp;</p

The Role of Mobile Genetic Elements in the Spread of Antimicrobial-Resistant Escherichia coli from Chickens to Humans in Small-Scale Production Poultry Operations in Rural Ecuador

© The Author(s) 2018. Small-scale production poultry operations are increasingly common worldwide. To investigate how these operations influence antimicrobial resistance and mobile genetic elements (MGEs), Escherichia coli isolates were sampled from small-scale production birds (raised in confined spaces with antibiotics in feed), household birds (no movement constraints; fed on scraps), and humans associated with these birds in rural Ecuador (2010-2012). Isolates were screened for genes associated with MGEs as well as phenotypic resistance to 12 antibiotics. Isolates from small-scale production birds had significantly elevated odds of resistance to 7 antibiotics and presence of MGE genes compared with household birds (adjusted odds ratio (OR) range = 2.2-87.9). Isolates from humans associated with small-scale production birds had elevated odds of carrying an integron (adjusted OR = 2.0; 95% confidence interval (CI): 1.06, 3.83) compared with humans associated with household birds, as well as resistance to sulfisoxazole (adjusted OR = 1.9; 95% CI: 1.01, 3.60) and trimethoprim/sulfamethoxazole (adjusted OR = 2.1; 95% CI: 1.13, 3.95). Stratifying by the presence of MGEs revealed antibiotic groups that are explained by biological links to MGEs; in particular, resistance to sulfisoxazole, trimethoprim/sulfamethoxazole, or tetracycline was highest among birds and humans when MGE exposures were present. Small-scale production poultry operations might select for isolates carrying MGEs, contributing to elevated levels of resistance in this setting

Association between arterial stiffness and variations in estrogen-related genes

available in PMC 2010 April 1.Increased arterial stiffness and wave reflection have been identified as cardiovascular disease risk factors. In light of significant sex differences and the moderate heritability of vascular function measures, we hypothesized that variation in the genes coding for oestrogen receptors α (ESR1) and β (ESR2) and aromatase (CYP19A1) is associated with aortic stiffness and pressure wave reflection as measured by non-invasive arterial tonometry. In all, 1261 unrelated Framingham Offspring Study participants who attended the seventh examination cycle (mean age 62±10 years, 52% women) and had arterial tonometry and genotyping data were included in the study. Analysis of covariance was used to assess the association of polymorphisms with forward wave amplitude, augmented pressure, augmentation index (AI), carotid–femoral pulse wave velocity and mean arterial pressure with adjustment for potential confounders. In the sex-pooled analysis, those homozygous for the minor allele at any of four ESR1 variants that were in strong linkage disequilibrium ((TA)n, rs2077647, rs2234693 and rs9340799) had on an average 18% higher augmented pressure and 16% greater AI compared with carriers of one or two major alleles (P=0.0002–0.01). A similar magnitude of association was detected in those homozygous for the common allele at two ESR2 single-nucleotide polymorphisms (P=0.007–0.02). Our results are consistent with the hypothesis that variation in ESR1 and ESR2, but not CYP19A1, is associated with an increased wave reflection that may contribute to associations between these variants and adverse clinical events demonstrated earlier. Our findings will need to be replicated in additional cohorts