Debugging and consolidating multiple synthetic chromosomes reveals combinatorial genetic interactions

The Sc2.0 project is building a eukaryotic synthetic genome from scratch. A major milestone has been achieved with all individual Sc2.0 chromosomes assembled. Here, we describe the consolidation of multiple synthetic chromosomes using advanced endoreduplication intercrossing with tRNA expression cassettes to generate a strain with 6.5 synthetic chromosomes. The 3D chromosome organization and transcript isoform profiles were evaluated using Hi-C and long-read direct RNA sequencing. We developed CRISPR Directed Biallelic URA3-assisted Genome Scan, or "CRISPR D-BUGS," to map phenotypic variants caused by specific designer modifications, known as "bugs." We first fine-mapped a bug in synthetic chromosome II (synII) and then discovered a combinatorial interaction associated with synIII and synX, revealing an unexpected genetic interaction that links transcriptional regulation, inositol metabolism, and tRNASerCGA abundance. Finally, to expedite consolidation, we employed chromosome substitution to incorporate the largest chromosome (synIV), thereby consolidating >50% of the Sc2.0 genome in one strain.

To Access the Role of Serum Procalcitonin in Predicting the Severity of Acute Pancreatitis

Background Acute Pancreatitis remains a common disorder with devastating consequences in severe form of disease. In this study we assessed serum procalcitonin for early prediction of severity of acute pancreatitis and compared it with multiple scoring systems and biomarkers. Objective This is a prospective comparative study in which 125 patients with diagnosis of acute pancreatitis were enrolled. All blood samples and imaging studies were obtained within 24-72 hours of admission and the severity was predicted. Method This is a prospective comparative study in which 125 patients with diagnosis of acute pancreatitis were enrolled. All blood samples and imaging studies were obtained within 24-72 hours of admission and the severity was predicted. Result Acute pancreatitis was graded severe in 54 patients and mild in 71 patients as per the Atlanta criteria. Receiver operating characteristic curve showed the area under curve of serum procalcitonin was higher (area under curve: 0.887, Confidence interval: 0.825-0.948) compared to computed tomography severity index scoring system (Area under curve: 0.841, Confidence interval: 0.771-0.911), Ranson's score (Area under curve: 0.796, Confidence interval: 0.715-0.876) and C-reactive protein (Area under curve: 0.717, Confidence interval: 0.628-0.8.7) in predicting the severity of acute pancreatitis. The best cut-off value of serum procalcitonin to predict severe acute pancreatitis was 0.9 ng/ml with 92.6% sensitivity, 80.3% specificity. The accuracy of serum procalcitonin (85.6%) was better than computed tomography severity index score (73.6 %), Ranson's score (76.8%) and C-reactive protein (64.8%). Conclusion Multifactorial scoring systems are complex and hard to use in clinical basis. Serum procalcitonin can be used as a promising single biomarker, easily done in all setup with better accuracy. And it is comparable to computed tomography severity index and Ranson's scores in earlier prediction of severity of acute pancreatitis.

Laparoscopic Appendectomy Versus Open Appendectomy for Acute Appendicitis: A Prospective Comparative Study

Background Appendicitis is the most common cause for acute abdominal pain. Laparoscopic appendectomy is an effective alternative to open appendectomy. It is a minimally invasive results in less postoperative pain, less wound infection, early return to normal work and less morbidity compared to open appendectomy. Both surgical methods are safe but there has been a controversy about which surgical procedure is the most appropriate. Objective To compare the outcomes of laparoscopic versus open appendectomy. Method In this prospective study, from January 2015 to April 2016, 212 cases of acute appendicitis were included. Diagnosis was based on Alvarado score of seven or above. Patients were distributed into two groups where every alternate patient was operated either open or laparoscopically. The groups were compared in terms of operative time, postoperative pain, postoperative wound infection, other morbidities and length of hospital stay. Result Of 212 patients, 106 underwent open and 104 underwent laparoscopic appendectomy. Other two patients, in whom laparoscopy was converted to open procedure, were excluded from the study. The mean operating time in laparoscopic appendectomy group was 44.57 ± 6.68 minutes and in open appendectomy group, was 36.34 ± 7.47 minutes (p < 0.05). The visual analog scale scores at 6th, 12th, 24th and 48th hours were higher in open appendectomy group compared to laparoscopic appendectomy group (p< 0.05). The hospital stay was 2.63 ± 0.60 days in laparoscopic appendectomy group and 3.26 ± 0.68 days in open appendectomy group (p < 0.05). Surgical site infection in laparoscopic appendectomy and open appendectomy group were 3.8% and 14 % respectively (p< 0.05). Conclusion In laparoscopic appendectomy group, there is lower incidence of wound infection, lesser postoperative analgesic requirement and shorter hospital stay in comparison to open appendectomy. Though, the operative time is more with laparoscopic appendectomy, it can be considered as the gold standard for surgical treatment of acute appendicitis.