KARRIKIN UP-REGULATED F-BOX 1 (KUF1) imposes negative feedback regulation of karrikin and KAI2 ligand metabolism in Arabidopsis thaliana.

SignificanceKarrikins are chemicals in smoke that stimulate regrowth of many plants after fire. However, karrikin responses are not limited to species from fire-prone environments and can affect growth after germination. Putatively, this is because karrikins mimic an unknown signal in plants, KAI2 ligand (KL). Karrikins likely require modification in plants to become bioactive. We identify a gene, KUF1, that appears to negatively regulate biosynthesis of KL and metabolism of a specific karrikin. KUF1 expression increases in response to karrikin or KL signaling, thus forming a negative feedback loop that limits further activation of the signaling pathway. This discovery will advance understanding of how karrikins are perceived and how smoke-activated germination evolved. It will also aid identification of the elusive KL.

Development of a fundamentals of endoscopic surgery proficiency-based skills curriculum for general surgery residents.

BACKGROUND: Fundamentals of Endoscopic Surgery (FES) has become a board certification requirement for general surgery residents. While the FES program provides a robust didactic curriculum, an endoscopic skills curriculum is lacking for this high stakes assessment. The aims of this study were to develop a proficiency-based endoscopic skills curriculum and assess its effectiveness on success in the FES exam. METHODS: Endoscopy experts developed a multiple-choice questionnaire based on the FES online didactics. Five training cases from the GI Mentor II simulator were selected, and expert performance defined proficiency levels for each case. Participating surgery residents were required to review online didactics and achieve proficiency twice on selected simulator cases. The multiple-choice questionnaire, simulator-generated metrics of two endoscopy cases, Global Assessment of Gastrointestinal Endoscopic Skills (GAGES), NASA-Task Load Index (TLX), and the manual portion of the FES exam were used for assessment before and after training. The curriculum was implemented either alongside a clinical endoscopy rotation or independent of the rotation. Clinical endoscopic skills of participants with a dedicated rotation were assessed using GAGES. RESULTS: Twenty-eight general surgery residents (PGY 2-5) participated in the study, of which 25 (89%) completed the curriculum. Scores of the multiple-choice questionnaire and all simulator-generated metrics improved in the post-training assessment, with the exception of the percentage of mucosal surface examined, which was slightly decreased. Simulated and clinical GAGES scores and the NASA-TLX score improved after training. Performance scores on four of five FES exam tasks were significantly improved. CONCLUSIONS: The proficiency-based endoscopic skills curriculum was successfully implemented both alongside the clinical endoscopy rotation and independent of the rotation. Participating residents acquired skills to pass the FES exam. This curriculum will be valuable to general surgery residency programs.

Extracellular electron uptake by autotrophic microbes: physiological, ecological, and evolutionary implications.

Microbes exchange electrons with their extracellular environment via direct or indirect means. This exchange is bidirectional and supports essential microbial oxidation-reduction processes, such as respiration and photosynthesis. The microbial capacity to use electrons from insoluble electron donors, such as redox-active minerals, poised electrodes, or even other microbial cells is called extracellular electron uptake (EEU). Autotrophs with this capability can thrive in nutrient and soluble electron donor-deficient environments. As primary producers, autotrophic microbes capable of EEU greatly impact microbial ecology and play important roles in matter and energy flow in the biosphere. In this review, we discuss EEU-driven autotrophic metabolisms, their mechanism and physiology, and highlight their ecological, evolutionary, and biotechnological implications.

Position Statement on the Use of Medical Cannabis for the Treatment of Epilepsy in Canada.

In Canada, recreational use of cannabis was legalized in October 2018. This policy change along with recent publications evaluating the efficacy of cannabis for the medical treatment of epilepsy and media awareness about its use have increased the public interest about this agent. The Canadian League Against Epilepsy Medical Therapeutics Committee, along with a multidisciplinary group of experts and Canadian Epilepsy Alliance representatives, has developed a position statement about the use of medical cannabis for epilepsy. This article addresses the current Canadian legal framework, recent publications about its efficacy and safety profile, and our understanding of the clinical issues that should be considered when contemplating cannabis use for medical purposes.

Énoncé de position quant à l'utilisation du cannabis médical dans le traitement de l'épilepsie. L'utilisation du cannabis à des fins récréatives a été légalisée au Canada en octobre 2018. Parallèlement à ce changement de politique, de récentes publication visant à évaluer l'efficacité du cannabis dans le traitement de l'épilepsie, de même qu'une sensibilisation médiatique accrue en ce qui concerne son utilisation, ont eu pour effet d'augmenter l'intérêt du grand public à son égard. Le Comité médical thérapeutique de la Ligue canadienne contre l'épilepsie (LCCE), de concert avec un groupe multidisciplinaire d'experts et des représentants de l'Alliance canadienne de l'épilepsie, a ainsi élaboré un énoncé de position en ce qui regarde l'utilisation du cannabis médical dans le traitement de l'épilepsie. Cet article entend donc aborder le cadre légal qui prévaut actuellement au Canada et examiner de récentes publications s'étant penchées sur le profil sécuritaire et sur l'efficacité du cannabis. De plus, nous voulons apporter un éclairage au sujet des aspects cliniques dont il faudrait tenir compte au moment d'envisager l'utilisation du cannabis à des fins médicales.

Towards sustainable bioplastic production using the photoautotrophic bacterium Rhodopseudomonas palustris TIE-1.

Bacterial synthesis of polyhydroxybutyrates (PHBs) is a potential approach for producing biodegradable plastics. This study assessed the ability of Rhodopseudomonas palustris TIE-1 to produce PHBs under various conditions. We focused on photoautotrophy using a poised electrode (photoelectroautotrophy) or ferrous iron (photoferroautotrophy) as electron donors. Growth conditions were tested with either ammonium chloride or dinitrogen gas as the nitrogen source. Although TIE-1's capacity to produce PHBs varied fairly under different conditions, photoelectroautotrophy and photoferroautotrophy showed the highest PHB electron yield and the highest specific PHB productivity, respectively. Gene expression analysis showed that there was no differential expression in PHB biosynthesis genes. This suggests that the variations in PHB accumulation might be post-transcriptionally regulated. This is the first study to systematically quantify the amount of PHB produced by a microbe via photoelectroautotrophy and photoferroautotrophy. This work could lead to sustainable bioproduction using abundant resources such as light, electricity, iron, and carbon dioxide.

Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death.

Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis.

A Model of Cost Reduction and Standardization: Improved Cost Savings While Maintaining the Quality of Care.

BACKGROUND: Surgeon instrument choices are influenced by training, previous experience, and established preferences. This causes variability in the cost of common operations, such as laparoscopic appendectomy. Many surgeons are unaware of the impact that this has on healthcare spending. OBJECTIVE: We sought to educate surgeons on their instrument use and develop standardized strategies for operating room cost reduction. DESIGN: We collected the individual surgeon instrument cost for performing a laparoscopic appendectomy. Sixteen surgeons were educated about these costs and provided with cost-effective instruments and techniques. SETTINGS: This study was conducted in a university-affiliated hospital system. PATIENTS: Patients included those undergoing a laparoscopic appendectomy within the hospital system. MAIN OUTCOME MEASURES: Patient demographics, operating room costs, and short-term outcomes for the fiscal year before and after the education program were then compared. RESULTS: During fiscal year 2013, a total of 336 laparoscopic appendectomies were performed compared with 357 in 2014. Twelve surgeons had a ≥5% reduction in average cost per case. Overall, the average cost per case was reduced by 17% (p < 0.001). Switching from an energy device to a stapler load or reusable plastic clip applier resulted in the largest savings per case at $321 or $442 per case. There were no differences in length of stay, 30-day readmissions, postoperative infections, operating time, or reoperations. LIMITATIONS: This retrospective study is subject to the accuracy of the medical chart system. In addition, specific instrument costs are based on our institution contracts and vary compared with other institutions. CONCLUSIONS: In this study we demonstrate that operative instrument costs for laparoscopic appendectomy can be significantly reduced by informing the surgeons of their operating room costs compared with their peers and providing a low-cost standardized instrument tray. Importantly, this can be realized without any incentive or punitive measures and does not negatively impact outcomes. Additional work is needed to expand these results to more operations, hospital systems, and training programs.

Multi-omics analysis of green lineage osmotic stress pathways unveils crucial roles of different cellular compartments.

Maintenance of water homeostasis is a fundamental cellular process required by all living organisms. Here, we use the single-celled green alga Chlamydomonas reinhardtii to establish a foundational understanding of osmotic-stress signaling pathways through transcriptomics, phosphoproteomics, and functional genomics approaches. Comparison of pathways identified through these analyses with yeast and Arabidopsis allows us to infer their evolutionary conservation and divergence across these lineages. 76 genes, acting across diverse cellular compartments, were found to be important for osmotic-stress tolerance in Chlamydomonas through their functions in cytoskeletal organization, potassium transport, vesicle trafficking, mitogen-activated protein kinase and chloroplast signaling. We show that homologs for five of these genes have conserved functions in stress tolerance in Arabidopsis and reveal a novel PROFILIN-dependent stage of acclimation affecting the actin cytoskeleton that ensures tissue integrity upon osmotic stress. This study highlights the conservation of the stress response in algae and land plants, and establishes Chlamydomonas as a unicellular plant model system to dissect the osmotic stress signaling pathway.

SMXL5 attenuates strigolactone signaling in Arabidopsis thaliana by inhibiting SMXL7 degradation.

Hormone-activated proteolysis is a recurring theme of plant hormone signaling mechanisms. In strigolactone signaling, the enzyme receptor DWARF14 (D14) and an F-box protein, MORE AXILLARY GROWTH2 (MAX2), mark SUPPRESSOR OF MAX2 1-LIKE (SMXL) family proteins SMXL6, SMXL7, and SMXL8 for rapid degradation. Removal of these transcriptional corepressors initiates downstream growth responses. The homologous proteins SMXL3, SMXL4, and SMXL5, however, are resistant to MAX2-mediated degradation. We discovered that the smxl4 smxl5 mutant has enhanced responses to strigolactone. SMXL5 attenuates strigolactone signaling by interfering with AtD14-SMXL7 interactions. SMXL5 interacts with AtD14 and SMXL7, providing two possible ways to inhibit SMXL7 degradation. SMXL5 function is partially dependent on an ethylene-responsive-element binding-factor-associated amphiphilic repression (EAR) motif, which typically mediates interactions with the TOPLESS family of transcriptional corepressors. However, we found that loss of the EAR motif reduces SMXL5-SMXL7 interactions and the attenuation of strigolactone signaling by SMXL5. We hypothesize that integration of SMXL5 into heteromeric SMXL complexes reduces the susceptibility of SMXL6/7/8 proteins to strigolactone-activated degradation and that the EAR motif promotes the formation or stability of these complexes. This mechanism may provide a way to spatially or temporally fine-tune strigolactone signaling through the regulation of SMXL5 expression or translation.

Single-port laparoscopic right hemicolectomy: the first 100 resections.

BACKGROUND: Single-port laparoscopy remains a novel technique in the field of colorectal surgery. Several small series have examined its safety for colon resection. OBJECTIVE: Our aim was to analyze our entire experience and short-term outcomes with single-port laparoscopic right hemicolectomy since its introduction at our institution. We assert that this approach is feasible and safe for the wide array of patients and indications encountered by a colorectal surgeon. DESIGN: This is a retrospective analysis of prospectively gathered data for all patients who underwent single-port laparoscopic right hemicolectomy with the use of standard laparoscopic instrumentation, for malignant or benign disease, between July 2009 and November 2010 in a high-volume, academic, colorectal surgery practice. MAIN OUTCOME MEASURES: Demographic, clinical, operative, and pathologic factors were reviewed and analyzed. All conversions to conventional laparoscopic or open operations were considered in this analysis. RESULTS: One hundred patients underwent single-port laparoscopic right hemicolectomy during the study period. Mean age was 63 years, and 61% of the patients were men. Forty-three percent had undergone previous abdominal surgery, and the median body mass index was 26 (range, 18-46). Median ASA classification was 3 (range, 1-4). Five percent of the operations were performed urgently, and 56% were performed for carcinoma, of which half were T3 or T4 tumor stage. Median operative duration was 105 (range, 64-270) minutes. Mean and median blood loss was 106 and 50 mL. Two percent required conversion to multiport laparoscopy, and 4% converted to the open approach. Median postoperative stay was 4 (range, 2-48) days. Median lymph node number was 18 (range, 11-42). There was one mortality in this series. Morbidity, including wound infection, was 13%. CONCLUSIONS: This represents the largest experience with single-port laparoscopic right hemicolectomy to date. This technique was used with acceptable morbidity and mortality and without compromise of conventional oncologic parameters by colorectal surgeons experienced in minimally invasive technique. These findings support the use of a single-port approach for patients requiring right hemicolectomy.

Complete Genome Sequence of Acidithiobacillus ferriphilus GT2, Isolated from Gold Mill Tailings.

We report the complete genome sequence of Acidithiobacillus ferriphilus GT2, an acidophile isolated from gold mill tailings. The circular genome of GT2 contains 2,489 predicted protein-coding units and a single plasmid. Functional analysis indicates the metabolic potential to oxidize iron and reduced sulfur compounds and to fix N2 and CO2.

Microbial Carbonation of Monocalcium Silicate.

Biocement formed through microbially induced calcium carbonate precipitation (MICP) is an emerging biotechnology focused on reducing the environmental impact of concrete production. In this system, CO2 species are provided via ureolysis by Sporosarcina pasteurii (S. pasteurii) to carbonate monocalcium silicate for MICP. This is one of the first studies of its kind that uses a solid-state calcium source, while prior work has used highly soluble forms. Our study focuses on microbial physiological, chemical thermodynamic, and kinetic studies of MICP. Monocalcium silicate incongruently dissolves to form soluble calcium, which must be coupled with CO2 release to form calcium carbonate. Chemical kinetic modeling shows that calcium solubility is the rate-limiting step, but the addition of organic acids significantly increases the solubility, enabling extensive carbonation to proceed up to 37 mol %. The microbial urease activity by S. pasteurii is active up to pH 11, 70 °C, and 1 mol L-1 CaCl2, producing calcite as a means of solidification. Cell-free extracts are also effective albeit less robust at extreme pH, producing calcite with different physical properties. Together, these data help determine the chemical, biological, and thermodynamic parameters critical for scaling microbial carbonation of monocalcium silicate to high-density cement and concrete.

A Course-Based Undergraduate Research Experience in CRISPR-Cas9 Experimental Design to Support Reverse Genetic Studies in Arabidopsis thaliana.

Gene-editing tools such as CRISPR-Cas9 have created unprecedented opportunities for genetic studies in plants and animals. We designed a course-based undergraduate research experience (CURE) to train introductory biology students in the concepts and implementation of gene-editing technology as well as develop their soft skills in data management and scientific communication. We present two versions of the course that can be implemented with twice-weekly meetings over a 5-week period. In the remote-learning version, students performed homology searches, designed guide RNAs (gRNAs) and primers, and learned the principles of molecular cloning. This version is appropriate when access to laboratory equipment or in-person instruction is limited, such as during closures that have occurred in response to the COVID-19 pandemic. In person, students designed gRNAs, cloned CRISPR-Cas9 constructs, and performed genetic transformation of Arabidopsis thaliana. Students learned how to design effective gRNA pairs targeting their assigned gene with an 86% success rate. Final exams tested students' ability to apply knowledge of an unfamiliar genome database to characterize gene structure and to properly design gRNAs. Average final exam scores of ∼73% and ∼84% for in-person and remote-learning CUREs, respectively, indicated that students met learning outcomes. The highly parallel nature of the CURE makes it possible to target dozens to hundreds of genes, depending on the number of sections. Applying this approach in a sensitized mutant background enables focused reverse genetic screens for genetic suppressors or enhancers. The course can be adapted readily to other organisms or projects that employ gene editing.

Photoferrotrophy and phototrophic extracellular electron uptake is common in the marine anoxygenic phototroph Rhodovulum sulfidophilum.

Photoferrotrophy allows anoxygenic phototrophs to use reduced iron as an electron donor for primary productivity. Recent work shows that freshwater photoferrotrophs can use electrons from solid-phase conductive substances via phototrophic extracellular electron uptake (pEEU), and the two processes share the underlying electron uptake mechanism. However, the ability of marine phototrophs to perform photoferrotrophy and pEEU, and the contribution of these processes to primary productivity is largely unknown. To fill this knowledge gap, we isolated 15 new strains of the marine anoxygenic phototroph Rhodovulum sulfidophilum on electron donors such as acetate and thiosulfate. We observed that all of the R. sulfidophilum strains isolated can perform photoferrotrophy. We chose strain AB26 as a representative strain to study further, and find that it can also perform pEEU from poised electrodes. We show that during pEEU, AB26 transfers electrons to the photosynthetic electron transport chain. Furthermore, systems biology-guided mutant analysis shows that R. sulfidophilum AB26 uses a previously unknown diheme cytochrome c protein, which we call EeuP, for pEEU but not photoferrotrophy. Homologs of EeuP occur in a range of widely distributed marine microbes. Overall, these results suggest that photoferrotrophy and pEEU contribute to the biogeochemical cycling of iron and carbon in marine ecosystems.

Single-port laparoscopic right hemicolectomy: a safe alternative to conventional laparoscopy.

PURPOSE: Single-port laparoscopic surgery has evolved from an effort to minimize tissue trauma, limit morbidity, and maximize cosmesis. Limited data exist comparing single-port with conventional laparoscopy for right colectomy. Our aim is to compare single-port with laparoscopic colectomy with regard to safety and feasibility. We assert that this approach can be adopted in a safe and efficacious manner while using standard laparoscopic instrumentation. METHODS: This is a retrospective analysis of prospectively gathered data regarding 16 single-port and 27 conventional laparoscopic right hemicolectomies performed by a single surgeon between January 2008 and February 2009. Demographics, operative outcomes, and morbidity were included and analyzed using either Student t test or Fisher exact probability test. RESULTS: Single-port and conventional laparoscopic groups were similar with regard to age, gender, body mass index, prior abdominal surgery, and co-morbidity. Seventy-five percent and 70% of the operations were performed for malignancy in the single-port and the conventional laparoscopy group, respectively (P = .69). Operative duration was 106 minutes in the single-port group vs 100 minutes in the conventional group (P = .64). Blood loss was 54 mL and 90 mL, respectively (P = .07). No conversions or additions of ports occurred. Hospital stay was 5.3 days in the single-port group vs 6 days in the conventional group (P = .53). Margins were negative in both groups. Mean lymph node number was 18 and 16 nodes (P = .92). There was one death in the conventional group (P = .44). Morbidity including wound infection was 18.8% and 14.9%, respectively (P = .73). CONCLUSIONS: These findings support single-port right colectomy as a safe and efficacious approach to right colon resections in patients eligible for laparoscopy with minimal additional equipment or learning curve for experienced laparoscopic colorectal surgeons. The single port was undertaken without an increase in morbidity or mortality. There was no increase in operative time with use of the single-port approach. Finally, adequate lymph node harvest and margin clearance was maintained.

Draft Genome Sequences of Four Rhodobacter sphaeroides Strains Isolated from a Marine Ecosystem.

Rhodobacter sphaeroides is an alphaproteobacterium found in freshwater and marine ecosystems. To better understand the metabolic diversity within this species, we isolated and sequenced four R. sphaeroides isolates obtained from Trunk River in Woods Hole, Massachusetts. Here, we report the draft genome sequences of R. sphaeroides AB24, AB25, AB27, and AB29.

Draft Genome Sequence of a Marine Photoferrotrophic Bacterium, Rhodovulum robiginosum DSM 12329T.

Here, we report the draft genome sequence of Rhodovulum robiginosum DSM 12329T, an anoxygenic phototroph isolated from a marine sediment in the North Sea (Jadebusen, Germany). This is the first genome for a marine photoferrotrophic bacterium, and it provides a genetic basis to understand the mechanistic underpinnings of photoferrotrophy in future studies.

Draft Genome Sequences of Two Closely Related Marichromatium Isolates, Photosynthetic Gammaproteobacteria from Marine Ecosystems.

Marichromatium species are photosynthetic gammaproteobacteria found in marine environments. Only two Marichromatium genomes are publicly available. Here, we report the draft genome sequences of two new Marichromatium strains isolated from Woods Hole, MA. These strains share >99% similarity to Marichromatium gracile and M. indicum based on 16S rRNA gene sequence analysis.

Phototrophic extracellular electron uptake is linked to carbon dioxide fixation in the bacterium Rhodopseudomonas palustris.

Extracellular electron uptake (EEU) is the ability of microbes to take up electrons from solid-phase conductive substances such as metal oxides. EEU is performed by prevalent phototrophic bacterial genera, but the electron transfer pathways and the physiological electron sinks are poorly understood. Here we show that electrons enter the photosynthetic electron transport chain during EEU in the phototrophic bacterium Rhodopseudomonas palustris TIE-1. Cathodic electron flow is also correlated with a highly reducing intracellular redox environment. We show that reducing equivalents are used for carbon dioxide (CO2) fixation, which is the primary electron sink. Deletion of the genes encoding ruBisCO (the CO2-fixing enzyme of the Calvin-Benson-Bassham cycle) leads to a 90% reduction in EEU. This work shows that phototrophs can directly use solid-phase conductive substances for electron transfer, energy transduction, and CO2 fixation.

Perioperative Management of Patients with Colovesical Fistula.

BACKGROUND: Colovesical fistula (CVF) is an uncommon complication of diverticulitis. Substantial heterogeneity exists in the perioperative management of this condition. We seek to evaluate the role of bladder leak testing, closed suction drainage, prolonged bladder catheter usage, and routine postoperative cystogram in the management of CVF. STUDY DESIGN: This is a retrospective study from a single academic health center investigation patients undergoing operation for diverticular CVF from 2005 to 2015 (n = 89). RESULTS: Patients undergoing operative repair for diverticular CVF resection had a mortality of 4% and overall morbidity of 46%. Intraoperative bladder leak test was performed in 36 patients (40%) and demonstrated a leak in 4 patients (11%). No patients with a negative intraoperative bladder leak test developed a urinary leak. Overall, five (6%) patients developed postoperative bladder leak. Three were identified by elevated drain creatinine and two by cystogram. The diagnostic yield of routine cystogram was 3%. All bladder leaks were diagnosed between postoperative day 3 and 7. Of patients with a postoperative bladder leak, none required reoperation and all resolved within 2 months. CONCLUSIONS: There is significant variability in the management of patients undergoing operation for CVF. Routine intraoperative bladder leak test should be performed. Cystogram may add cost and is low yield for routine evaluation for bladder leak after operation for CVF. Urinary catheter removal before postoperative day 7 should be considered.