A genome-wide cytotoxicity screen of cluster F1 mycobacteriophage Girr reveals novel inhibitors of Mycobacterium smegmatis growth.

Over the past decade, thousands of bacteriophage genomes have been sequenced and annotated. A striking observation from this work is that known structural features and functions cannot be assigned for >65% of the encoded proteins. One approach to begin experimentally elucidating the function of these uncharacterized gene products is genome-wide screening to identify phage genes that confer phenotypes of interest like inhibition of host growth. This study describes the results of a screen evaluating the effects of overexpressing each gene encoded by the temperate Cluster F1 mycobacteriophage Girr on the growth of the host bacterium Mycobacterium smegmatis. Overexpression of 29 of the 102 Girr genes (~28% of the genome) resulted in mild to severe cytotoxicity. Of the 29 toxic genes described, 12 have no known function and are predominately small proteins of <125 amino acids. Overexpression of the majority of these 12 cytotoxic no known functions proteins resulted in moderate to severe growth reduction and represent novel antimicrobial products. The remaining 17 toxic genes have predicted functions, encoding products involved in phage structure, DNA replication/modification, DNA binding/gene regulation, or other enzymatic activity. Comparison of this dataset with prior genome-wide cytotoxicity screens of mycobacteriophages Waterfoul and Hammy reveals some common functional themes, though several of the predicted Girr functions associated with cytotoxicity in our report, including genes involved in lysogeny, have not been described previously. This study, completed as part of the HHMI-supported SEA-GENES project, highlights the power of parallel, genome-wide overexpression screens to identify novel interactions between phages and their hosts.

Robotic hepatectomy for benign and malignant liver tumors.

Minimally invasive hepatectomy for benign and malignant liver lesions has gained popularity in the past decade due to improved perioperative outcomes when compared to conventional 'open' technique. We aim to investigate our initial experience of robotic hepatectomy undertaken in our hepatobiliary program. All patients undergoing robotic hepatectomy between 2013 and 2018 were prospectively followed. Data are presented as median (mean ± SD). A total of 80 patients underwent robotic hepatectomy within the study period. 60% of the patients were women, age of 63 (62.4 ± 14.1), body mass index of 28 (29.6 ± 9.4), ASA class of 2.5 (2.5 ± 0.6), and MELD score of 7 (8.2 ± 2.8). Size of resected lesion was 3.9 (4.6 ± 3) cm. Indications for resection were metastatic lesions (30%), hepatocellular carcinoma (28%), cholangiocarcinoma (7%), gallbladder cancer (5%), neuroendocrine tumors (4%), and benign lesions (26%). Formal hepatectomy (right or left) was performed in 30% of the patients. Operative time was 233 (267.2 ± 109.6) minutes, and estimated blood loss was 150 (265.7 ± 319.9) ml. Length of hospital stay was 3 (5.0 ± 4.6) days. One patient was converted to 'open' approach. 10 patients experienced postoperative complications. Readmissions within 30 days of hospital discharge were seen in eight patients. Our data support that robotic hepatectomy is safe and feasible, with favorable short-term outcomes and low conversion rate. Robotic technology extends the application of minimally invasive techniques in the field of hepatobiliary surgery.