The response regulator Npun_F1278 is essential for scytonemin biosynthesis in the cyanobacterium Nostoc punctiforme ATCC 29133.

Following exposure to long-wavelength ultraviolet radiation (UVA), some cyanobacteria produce the indole-alkaloid sunscreen scytonemin. The genomic region associated with scytonemin biosynthesis in the cyanobacterium Nostoc punctiforme includes 18 cotranscribed genes. A two-component regulatory system (Npun_F1277/Npun_F1278) directly upstream from the biosynthetic genes was identified through comparative genomics and is likely involved in scytonemin regulation. In this study, the response regulator (RR), Npun_F1278, was evaluated for its ability to regulate scytonemin biosynthesis using a mutant strain of N. punctiforme deficient in this gene, hereafter strain Δ1278. Following UVA radiation, the typical stimulus to initiate scytonemin biosynthesis, Δ1278 was incapable of producing scytonemin. A phenotypic characterization of Δ1278 suggests that aside from the ability to produce scytonemin, the deletion of the Npun_F1278 gene does not affect the cellular morphology, cellular differentiation capability, or lipid-soluble pigment complement of Δ1278 compared to the wildtype. The mutant, however, had a slower specific growth rate under white light and produced ~2.5-fold more phycocyanin per cell under UVA than the wildtype. Since Δ1278 does not produce scytonemin, this study demonstrates that the RR gene, Npun_F1278, is essential for scytonemin biosynthesis in N. punctiforme. While most of the evaluated effects of this gene appear to be specific for scytonemin, this regulator may also influence the overall health of the cell and phycobiliprotein synthesis, directly or indirectly. This is the first study to identify a regulatory gene involved in the biosynthesis of the sunscreen scytonemin and posits a link between cell growth, pigment synthesis, and sunscreen production.

Early Post-Operative Events After Urethroplasty in Obese Patients: A Multi-Institutional Retrospective Series.

OBJECTIVE: To compare early urethroplasty outcomes in non-obese, obese and morbidly obese patients undergoing urethroplasty for urethral stricture disease. The impact of obesity on outcomes is poorly understood but will be increasingly important as obesity continues to rise. METHODS: Patients underwent urethroplasty at one of the 5 institutions between January 2016 and December 2020. Obese (BMI 30-39.9, n = 72) and morbidly obese (BMI >40, n = 49) patients were compared to normal weight (BMI <25, n = 29) and overweight (BMI 25-29.9, n = 51) patients. Demographics, comorbidities, and stricture characteristics were collected. Outcomes including complications, recurrence, and secondary interventions were compared using univariate and multivariate analysis. RESULTS: Two hundred and one patients (Mean BMI 34.1, Range 18.4-65.2) with mean age 52.2 years (SD=17.2) were analyzed. Median follow-up time was 3.71 months. Obese patients were younger (P = .008), had more anterior (P <.001), iatrogenic and LS-associated strictures (P = .036). Sixty-day complication rate was 26.3% with no differences between cohorts (P = .788). Around 9.5% of patients had extravasation at catheter removal, 18.9% reported stricture recurrence, and 7.4% required additional interventions. Obese patients had greater estimated blood loss (P = .001) and length of stay (P = .001). On multivariate analysis, smoking associated with contrast leak (OR 7.176, 95% CI 1.13-45.5) but not recurrence or need for intervention (P = .155, .927). CONCLUSION: Obese patients in our cohort had more anterior, iatrogenic, and LS-related strictures. However, obesity is not associated with complications, contrast leak, secondary interventions, or recurrence. Obese had higher blood loss and length of stay. Urethroplasty is safe and effective in obese patients.

Expression of Scytonemin Biosynthesis Genes under Alternative Stress Conditions in the Cyanobacterium Nostoc punctiforme.

The indole-alkaloid scytonemin is a sunscreen pigment that is widely produced among cyanobacteria as an ultraviolet radiation (UVR) survival strategy. Scytonemin biosynthesis is encoded by two gene clusters that are known to be induced by long-wavelength radiation (UVA). Previous studies have characterized the transcriptome of cyanobacteria in response to a wide range of conditions, but the effect on the expression of scytonemin biosynthesis genes has not been specifically targeted. Therefore, the aim of this study is to determine the variable response of scytonemin biosynthesis genes to a variety of environmental conditions. Cells were acclimated to white light before supplementation with UVA, UVB, high light, or osmotic stress for 48 h. The presence of scytonemin was determined by absorbance spectroscopy and gene expression of representative scytonemin biosynthesis genes was measured using quantitative PCR. Scytonemin genes were up-regulated in UVA, UVB, and high light, although the scytonemin pigment was not detected under high light. There was no scytonemin or upregulation of these genes under osmotic stress. The lack of pigment production under high light, despite increased gene expression, suggests a time-dependent delay for pigment production or additional mechanisms or genes that may be involved in scytonemin production beyond those currently known.

In Situ Visualization for Computational Science.

In situ visualization is an increasingly important approach for computational science, as it can address limitations on leading edge high-performance computers and also can provide an increased spatio-temporal resolution. However, there are many open research issues with effective in situ processing. This article describes the challenges identified by a recent Dagstuhl Seminar on the topic.

New state record for the Asian tiger mosquito, Aedes albopictus (Skuse).

The 1st Aedes albopictus specimen recorded from Colorado was found near a tire storage site in Ft. Lupton on July 9, 2003. Intensified surveillance at the site in 2003 did not result in collection of any other specimens that season, leading to speculation that it was an isolated incident rather than an actual introduction for the species. Control measures against larvae and adult mosquitoes were conducted in the area to further reduce the likelihood of establishment of a viable population. However, subsequent surveillance during the 2004 mosquito season resulted in collection of 21 additional specimens at and near the Ft. Lupton site, possibly representing an established viable population of the species.

Topological segmentation in three-dimensional vector fields.

We present a new method for topological segmentation in steady three-dimensional vector fields. Depending on desired properties, the algorithm replaces the original vector field by a derived segmented data set, which is utilized to produce separating surfaces in the vector field. We define the concept of a segmented data set, develop methods that produce the segmented data by sampling the vector field with streamlines, and describe algorithms that generate the separating surfaces. This method is applied to generate local separatrices in the field, defined by a movable boundary region placed in the field. The resulting partitions can be visualized using standard techniques for a visualization of a vector field at a higher level of abstraction.

Outbreak of shiga toxin-producing Escherichia coli serotype O26: H11 infection at a child care center in Colorado.

BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) O26:H11 is an emerging cause of disease with serious potential consequences in children. The epidemiology and clinical spectrum of O26:H11 are incompletely understood. We investigated an outbreak of O26:H11 infection among children younger than 48 months of age and employees at a child care center. METHODS: Every employee at the center (n = 20) and every child <48 months (n = 55) were tested for STEC and administered a questionnaire. Thirty environmental health inspections and site visits were conducted. A cohorting strategy for disease control was implemented. RESULTS: Eighteen confirmed and 27 suspect cases were detected. There were no hospitalizations. The illness rate was 60% for children and employees. The risk of being a case in children <36 months was twice the risk among children of 36 to 47 months (risk ratio: 2.10; 95% confidence interval: 1.00, 4.42). The median duration of shedding among symptomatic confirmed cases was 30.5 days (range: 14-52 days). Four (22%) confirmed cases were asymptomatic and 3 (17%) shed intermittently. Nearly half (49%) of the household contacts of confirmed cases developed a diarrheal illness. The outbreak was propagated by person-to-person transmission; cohorting was an effective disease control strategy. CONCLUSIONS: This was the largest reported outbreak of O26:H11 infection in the United States and the largest reported non-O157 STEC outbreak in a US child care center. Non-O157 STEC infection is a differential diagnosis for outbreaks of diarrhea in child care settings. Aggressive disease control measures were effective but should be evaluated for outbreaks in other settings.

Feature-based statistical analysis of combustion simulation data.

We present a new framework for feature-based statistical analysis of large-scale scientific data and demonstrate its effectiveness by analyzing features from Direct Numerical Simulations (DNS) of turbulent combustion. Turbulent flows are ubiquitous and account for transport and mixing processes in combustion, astrophysics, fusion, and climate modeling among other disciplines. They are also characterized by coherent structure or organized motion, i.e. nonlocal entities whose geometrical features can directly impact molecular mixing and reactive processes. While traditional multi-point statistics provide correlative information, they lack nonlocal structural information, and hence, fail to provide mechanistic causality information between organized fluid motion and mixing and reactive processes. Hence, it is of great interest to capture and track flow features and their statistics together with their correlation with relevant scalar quantities, e.g. temperature or species concentrations. In our approach we encode the set of all possible flow features by pre-computing merge trees augmented with attributes, such as statistical moments of various scalar fields, e.g. temperature, as well as length-scales computed via spectral analysis. The computation is performed in an efficient streaming manner in a pre-processing step and results in a collection of meta-data that is orders of magnitude smaller than the original simulation data. This meta-data is sufficient to support a fully flexible and interactive analysis of the features, allowing for arbitrary thresholds, providing per-feature statistics, and creating various global diagnostics such as Cumulative Density Functions (CDFs), histograms, or time-series. We combine the analysis with a rendering of the features in a linked-view browser that enables scientists to interactively explore, visualize, and analyze the equivalent of one terabyte of simulation data. We highlight the utility of this new framework for combustion science; however, it is applicable to many other science domains.