Resonant domain-wall-enhanced tunable microwave ferroelectrics.

Ordering of ferroelectric polarization1 and its trajectory in response to an electric field2 are essential for the operation of non-volatile memories3, transducers4 and electro-optic devices5. However, for voltage control of capacitance and frequency agility in telecommunication devices, domain walls have long been thought to be a hindrance because they lead to high dielectric loss and hysteresis in the device response to an applied electric field6. To avoid these effects, tunable dielectrics are often operated under piezoelectric resonance conditions, relying on operation well above the ferroelectric Curie temperature7, where tunability is compromised. Therefore, there is an unavoidable trade-off between the requirements of high tunability and low loss in tunable dielectric devices, which leads to severe limitations on their figure of merit. Here we show that domain structure can in fact be exploited to obtain ultralow loss and exceptional frequency selectivity without piezoelectric resonance. We use intrinsically tunable materials with properties that are defined not only by their chemical composition, but also by the proximity and accessibility of thermodynamically predicted strain-induced, ferroelectric domain-wall variants8. The resulting gigahertz microwave tunability and dielectric loss are better than those of the best film devices by one to two orders of magnitude and comparable to those of bulk single crystals. The measured quality factors exceed the theoretically predicted zero-field intrinsic limit owing to domain-wall fluctuations, rather than field-induced piezoelectric oscillations, which are usually associated with resonance. Resonant frequency tuning across the entire L, S and C microwave bands (1-8 gigahertz) is achieved in an individual device-a range about 100 times larger than that of the best intrinsically tunable material. These results point to a rich phase space of possible nanometre-scale domain structures that can be used to surmount current limitations, and demonstrate a promising strategy for obtaining ultrahigh frequency agility and low-loss microwave devices.

Importance of microbial amphiphiles: interaction potential of biosurfactants, amyloids, and other exo-polymeric-substances.

Microorganisms produce a diverse group of biomolecules having amphipathic nature (amphiphiles). Microbial amphiphiles, including amyloids, bio-surfactants, and other exo-polymeric substances, play a crucial role in various biological processes and have gained significant attention recently. Although diverse in biochemical composition, these amphiphiles have been reported for common microbial traits like biofilm formation and pathogenicity due to their ability to act as surface active agents with active interfacial properties essential for microbes to grow in various niches. This enables microbes to reduce surface tension, emulsification, dispersion, and attachment at the interface. In this report, the ecological importance and biotechnological usage of important amphiphiles have been discussed. The low molecular weight amphiphiles like biosurfactants, siderophores, and peptides showing helical and antimicrobial activities have been extensively reported for their ability to work as quorum-sensing mediators. While high molecular weight amphiphiles make up amyloid fibers, exopolysaccharides, liposomes, or magnetosomes have been shown to have a significant influence in deciding microbial physiology and survival. In this report, we have discussed the functional similarities and biochemical variations of several amphipathic biomolecules produced by microbes, and the present report shows these amphiphiles showing polyphyletic and ecophysiological groups of microorganisms and hence can `be replaced in biotechnological applications depending on the compatibility of the processes.

General Versus Neuraxial Anesthesia in Revision Surgery for Periprosthetic Joint Infection.

BACKGROUND: The purpose of this study was to compare neuraxial and general anesthesia in revision surgery for periprosthetic joint infection (PJI). METHODS: Patients undergoing revision arthroplasty for PJI were identified in the 2005-2019 American College of Surgeons National Surgical Quality Improvement Program databases. Thirty-day outcomes were compared between general and neuraxial anesthesia. Propensity-score matching and multivariate analysis were used to control patient and procedural variables. RESULTS: Neuraxial anesthesia was used in 1511 (16.8%) cases and general anesthesia in 7468 (83.2%) cases. Neuraxial anesthesia had a lower risk of any adverse event (odds ratio [OR] 0.70, P < .001), serious adverse events (OR 0.77, P < .001), and minor adverse events (OR 0.66, P < .001). Among 875 reoperations and 1351 readmissions, two had a diagnosis of intraspinal abscess, both occurring after general anesthesia. CONCLUSIONS: Neuraxial anesthesia was associated with a lower risk of adverse events when compared to general anesthesia in revision surgery for PJI.

Emergent chirality in the electric polarization texture of titanate superlattices.

Chirality is a geometrical property by which an object is not superimposable onto its mirror image, thereby imparting a handedness. Chirality determines many important properties in nature-from the strength of the weak interactions according to the electroweak theory in particle physics to the binding of enzymes with naturally occurring amino acids or sugars, reactions that are fundamental for life. In condensed matter physics, the prediction of topologically protected magnetic skyrmions and related spin textures in chiral magnets has stimulated significant research. If the magnetic dipoles were replaced by their electrical counterparts, then electrically controllable chiral devices could be designed. Complex oxide BaTiO3/SrTiO3 nanocomposites and PbTiO3/SrTiO3 superlattices are perfect candidates, since "polar vortices," in which a continuous rotation of ferroelectric polarization spontaneously forms, have been recently discovered. Using resonant soft X-ray diffraction, we report the observation of a strong circular dichroism from the interaction between circularly polarized light and the chiral electric polarization texture that emerges in PbTiO3/SrTiO3 superlattices. This hallmark of chirality is explained by a helical rotation of electric polarization that second-principles simulations predict to reside within complex 3D polarization textures comprising ordered topological line defects. The handedness of the texture can be topologically characterized by the sign of the helicity number of the chiral line defects. This coupling between the optical and novel polar properties could be exploited to encode chiral signatures into photon or electron beams for information processing.

A Matched Comparison of Postoperative Complications Between Smokers and Nonsmokers Following Open Reduction Internal Fixation of Distal Radius Fractures.

PURPOSE: The purpose of the present study was to identify differences in 30-day adverse events, reoperations, readmissions, and mortality for smokers and nonsmokers who undergo operative treatment for a distal radius fracture. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was queried for patients who had operatively treated distal radius fractures between 2005 and 2017. Patient characteristics and surgical variables were assessed. Thirty-day outcome data were collected on serious (SAEs) and minor adverse events (MAEs), as well as on infection, return to the operating room, readmission, and mortality. Multivariable logistic analyses with and without propensity-score matching was used to compare outcome measures between the smoker and the nonsmoker cohorts. RESULTS: In total, 16,158 cases were identified, of whom 3,062 were smokers. After 1:1 propensity-score matching, the smoking and nonsmoking cohorts had similar demographic characteristics. Based on the multivariable propensity-matched logistic regression, cases in the smoking group had a significantly higher rate of any adverse event (AAE) (odds ratio [OR], 1.75; 95% confidence interval [95% CI], 1.28-2.38), serious adverse event (SAE) (OR, 1.75; 95% CI, 1.22-2.50), and minor adverse event (MAE) (OR, 1.84; 95% CI, 1.04-3.23). Smokers also had higher rates of infection (OR, 1.73; 95% CI, 1.26-2.39), reoperation (OR, 2.07; 95% CI, 1.13-3.78), and readmission (OR, 1.83; 95% CI, 1.20-2.79). There was no difference in 30-day mortality rate. CONCLUSIONS: Smokers who undergo open reduction internal fixation of distal radius fractures had an increased risk of 30-day perioperative adverse events, even with matching and controlling for demographic characteristics and comorbidity status. This information can be used for patient counseling and may be helpful for treatment/management planning. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

The chromatin remodeling complex Swi/Snf regulates splicing of meiotic transcripts in Saccharomyces cerevisiae.

Despite its relatively streamlined genome, there are important examples of regulated RNA splicing in Saccharomyces cerevisiae, such as splicing of meiotic transcripts. Like other eukaryotes, S. cerevisiae undergoes a dramatic reprogramming of gene expression during meiosis, including regulated splicing of a number of crucial meiosis-specific RNAs. Splicing of a subset of these is dependent upon the splicing activator Mer1. Here we show a crucial role for the chromatin remodeler Swi/Snf in regulation of splicing of meiotic genes and find that the complex affects meiotic splicing in two ways. First, we show that Swi/Snf regulates nutrient-dependent downregulation of ribosomal protein encoding RNAs, leading to the redistribution of spliceosomes from this abundant class of intron-containing RNAs (the ribosomal protein genes) to Mer1-regulated transcripts. We also demonstrate that Mer1 expression is dependent on Snf2, its acetylation state and histone H3 lysine 9 acetylation at the MER1 locus. Hence, Snf2 exerts systems level control of meiotic gene expression through two temporally distinct mechanisms, demonstrating that it is a key regulator of meiotic splicing in S. cerevisiae. We also reveal an evolutionarily conserved mechanism whereby the cell redirects its energy from maintaining its translational capacity to the process of meiosis.

Industry Payments to Pediatric Orthopaedic Surgeons Reported by the Open Payments Database: 2014 to 2017.

BACKGROUND: The Open Payments Database (OPD), mandated by the Sunshine Act, is a national registry of physician-industry transactions. Payments are reported as either General, Research, or Ownership payments. The current study aims to investigate trends in OPD General payments reported to pediatric orthopaedic surgeons from 2014 to 2017. METHODS: General industry payments made to pediatric orthopaedic surgeons (as identified by OPD) were characterized by median payment, payment subtype, and census region. As fewer Research and Ownership payments were made, only payment totals for these categories were determined. General payment data were analyzed for trends using the nonparametric Mann-Whitney U test. RESULTS: For General payments, there was an increase in the number of compensated pediatric orthopaedists from 2014 to 2017 (324 vs. 429). Of those compensated, there was no significant change in median payment per compensated surgeon ($201 vs. $197; P=0.82). However, a large percentage of total General payment dollars in pediatric orthopaedics were made to the top 5% of compensated pediatric orthopaedists each year (average 71% of total General industry compensation). For this top 5% group, median General payment per compensated surgeon increased from 2014 ($14,624) to 2017 ($32,752) (P=0.006). A significant increase in median subtype aggregate payment per surgeon was observed in the education (P<0.001) and royalty/license (P=0.031) subtypes; a significant decrease was observed for travel/lodging payments (P=0.01). Midwest pediatric orthopaedists received the highest median payment across all years studied. Few payments for research and ownership were made to pediatric orthopaedists. Four-year aggregate payment totals were $18,151 and $3,223,554 for Research and Ownership payments, respectively. CONCLUSIONS: Many expected payments to surgeons to decrease when put under the public scrutiny of the OPD. Not only was this decrease not observed for General payments to pediatric orthopaedic surgeons during the 2014 to 2017 period, but also the median General payment to the top 5% increased. These findings are important to note in the current era of increased transparency. LEVEL OF EVIDENCE: Level III.

Abnormally High, as Well as Low, Preoperative Platelet Counts Correlate With Adverse Outcomes and Readmissions After Elective Total Knee Arthroplasty.

BACKGROUND: Laboratory studies are routinely performed as a part of the preoperative workup for a total knee arthroplasty (TKA). The ramifications of abnormal preoperative platelet counts remain uncharacterized in large, multicenter patient populations. METHODS: Patients who underwent elective primary TKA were identified in the 2011-2015 National Surgical Quality Improvement Program database. Risk of 30-day postoperative complications was calculated as a function of preoperative platelet counts. Patients were characterized as having a normal platelet count, abnormally low platelet count, and abnormally high platelet count based on relative risk calculations. Univariate and multivariate analyses were performed to associate abnormal platelet counts with patient demographics, operative variables, 30-day postoperative complications, and readmissions. RESULTS: In total, 140,073 patients who underwent elective TKA were identified. Using the relative risk threshold of 1.5 for any adverse event, abnormally low and abnormally high platelet count thresholds were set at ≤116,000/mL and ≥492,000/mL, respectively. Multivariate analyses revealed low platelet counts to be associated with higher rates of any, major, and minor adverse events and longer length of stay. Analogously, high platelet counts were associated with higher rates of any and minor adverse events and longer length of stay. CONCLUSION: The present study employed a large patient sample size and showed that elective TKA patients with abnormally high, as well as low, platelet counts are at increased risk of postoperative adverse outcomes. Focused attention needs to be paid to TKA patients with preoperative abnormal platelet counts for optimization and postoperative care. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Mycelial form of dimorphic fungus Malassezia species dictates the microbial interaction.

Dandruff is one of the most common clinically manifested and studied scalp disorders. It has been associated with both bacteria and fungi. Bacteria and fungi inhabiting the scalp are known to influence each other and manifestation of dandruff. Fungal and bacterial isolates from scalp epithelial flakes (dandruff) were identified by rDNA sequencing. Local oils were tested for fungal and bacterial inhibition, interaction and biofilm formation, cell-cell interactions were studied by auto aggregation and surface thermodynamics studies. The isolates Bacillus sp.C2b1 (MK036745) and Malassezia sp. C2y1 (MK036746) were inhibited by Mahabhrungraj oil. The fungal morphological switch was evident and dependent on nutrition. Cell aggregation studies suggested the interaction of bacteria with yeast (non-pathogenic) phase of the fungus. Bacterial and yeast cells were found to be compatible for biofilm formation. The fungal mycelial surfaces were found to be conducive for interaction with both bacterial cells and yeast forms. The results here indicate the significance of mycelial phase of scalp-isolated fungus in interaction with the bacterial surfaces and also with self-yeast phase surface. This is the first report of the interaction between scalp-isolated microorganisms with respect to their surface interaction capabilities.

Characterization of Solibacillus silvestris strain AM1 that produces amyloid bioemulsifier.

Solibacillus silvestris AM1 was the first strain from the genus to be reported for the production of a functional amyloid and its potential use as a surface active agent, a thermostable glycoprotein amyloid bioemulsifier BE-AM1 capable of influencing environment and biofilm formation. Phylogenetic analysis based on 16S rRNA gene, molecular characterization studies on the basis of DNA-DNA hybridization and chemotaxonomic fatty acid methyl ester (FAME) analysis showed that S. silvestris AM1 as a strain matches with the type strain S. silvestris HR3-23. But strain AM1 differs from the type strain HR3-23 in carbon substrate utilization studies along with amyloid bioemulsifier production ability with potential industrial and environmental applications. S. silvestris AM1 exhibited bioemulsifier production at wide range of factors like pH and NaCl concentrations, while temperature influenced the bioemulsifier production indirectly (since it affected the growth). Bioemulsifier production was observed even at oligotrophic conditions (0.5 mg ml-1 ) seen usually in its native environment. In this study, we have characterized the amyloid producing S. silvestris AM1 taxonomically and also analyzed 16S rDNA of 103 sequences of Solibacillus sp. available, which indicated the possibility of new species in this genus and can be studied for industrially and environmentally important biomolecules.

Stability of Polar Vortex Lattice in Ferroelectric Superlattices.

A novel mesoscale state comprising of an ordered polar vortex lattice has been demonstrated in ferroelectric superlattices of PbTiO3/SrTiO3. Here, we employ phase-field simulations, analytical theory, and experimental observations to evaluate thermodynamic conditions and geometric length scales that are critical for the formation of such exotic vortex states. We show that the stability of these vortex lattices involves an intimate competition between long-range electrostatic, long-range elastic, and short-range polarization gradient-related interactions leading to both an upper and a lower bound to the length scale at which these states can be observed. We found that the critical length is related to the intrinsic domain wall width, which could serve as a simple intuitive design rule for the discovery of novel ultrafine topological structures in ferroic systems.

Mutation Detection in Patients With Advanced Cancer by Universal Sequencing of Cancer-Related Genes in Tumor and Normal DNA vs Guideline-Based Germline Testing.

Importance: Guidelines for cancer genetic testing based on family history may miss clinically actionable genetic changes with established implications for cancer screening or prevention. Objective: To determine the proportion and potential clinical implications of inherited variants detected using simultaneous sequencing of the tumor and normal tissue ("tumor-normal sequencing") compared with genetic test results based on current guidelines. Design, Setting, and Participants: From January 2014 until May 2016 at Memorial Sloan Kettering Cancer Center, 10 336 patients consented to tumor DNA sequencing. Since May 2015, 1040 of these patients with advanced cancer were referred by their oncologists for germline analysis of 76 cancer predisposition genes. Patients with clinically actionable inherited mutations whose genetic test results would not have been predicted by published decision rules were identified. Follow-up for potential clinical implications of mutation detection was through May 2017. Exposure: Tumor and germline sequencing compared with the predicted yield of targeted germline sequencing based on clinical guidelines. Main Outcomes and Measures: Proportion of clinically actionable germline mutations detected by universal tumor-normal sequencing that would not have been detected by guideline-directed testing. Results: Of 1040 patients, the median age was 58 years (interquartile range, 50.5-66 years), 65.3% were male, and 81.3% had stage IV disease at the time of genomic analysis, with prostate, renal, pancreatic, breast, and colon cancer as the most common diagnoses. Of the 1040 patients, 182 (17.5%; 95% CI, 15.3%-19.9%) had clinically actionable mutations conferring cancer susceptibility, including 149 with moderate- to high-penetrance mutations; 101 patients tested (9.7%; 95% CI, 8.1%-11.7%) would not have had these mutations detected using clinical guidelines, including 65 with moderate- to high-penetrance mutations. Frequency of inherited mutations was related to case mix, stage, and founder mutations. Germline findings led to discussion or initiation of change to targeted therapy in 38 patients tested (3.7%) and predictive testing in the families of 13 individuals (1.3%), including 6 for whom genetic evaluation would not have been initiated by guideline-based testing. Conclusions and Relevance: In this referral population with selected advanced cancers, universal sequencing of a broad panel of cancer-related genes in paired germline and tumor DNA samples was associated with increased detection of individuals with potentially clinically significant heritable mutations over the predicted yield of targeted germline testing based on current clinical guidelines. Knowledge of these additional mutations can help guide therapeutic and preventive interventions, but whether all of these interventions would improve outcomes for patients with cancer or their family members requires further study. Trial Registration: clinicaltrials.gov Identifier: NCT01775072.

Ferroelectric polarization reversal via successive ferroelastic transitions.

Switchable polarization makes ferroelectrics a critical component in memories, actuators and electro-optic devices, and potential candidates for nanoelectronics. Although many studies of ferroelectric switching have been undertaken, much remains to be understood about switching in complex domain structures and in devices. In this work, a combination of thin-film epitaxy, macro- and nanoscale property and switching characterization, and molecular dynamics simulations are used to elucidate the nature of switching in PbZr(0.2)Ti(0.8)O3 thin films. Differences are demonstrated between (001)-/(101)- and (111)-oriented films, with the latter exhibiting complex, nanotwinned ferroelectric domain structures with high densities of 90° domain walls and considerably broadened switching characteristics. Molecular dynamics simulations predict both 180° (for (001)-/(101)-oriented films) and 90° multi-step switching (for (111)-oriented films) and these processes are subsequently observed in stroboscopic piezoresponse force microscopy. These results have implications for our understanding of ferroelectric switching and offer opportunities to change domain reversal speed.

Effective remediation of fish processing waste using mixed culture biofilms capable of simultaneous nitrification and denitrification.

Fish processing waste water causes pollution and eutrophication of water bodies when released untreated. Use of bacteria capable of simultaneous nitrification and denitrification (SND) as biofilms on carriers in a moving bed bioreactor (MBBR) is a popular approach but seldom used for fish processing waste water remediation. Here, we studied the variations in biofilm formation and application activities by isolates Lysinibacillus sp. HT13, Alcaligenes sp. HT15 and Proteus sp. HT37 previously reported by us. While HT13 and HT15 formed significantly higher biofilms in polystyrene microtitre plates than on carriers, HT37 exhibited highest on carriers. A consortium of the three selected bacteria grown as biofilm on MBBR carriers exhibited better remediation of ammonia (200-600 ppm and 50 mM) than the individual isolates on carriers. The mixed biofilm set on the carriers was used for nitrogenous waste removal from fish processing waste water in 2 and 20 L setups. The total nitrogen estimated by elemental analysis showed complete remediation from 250 ppm in both 2 and 20 L waste water systems within 48 h. The usual toxic nitrogenous components-ammonia, nitrite and nitrate were also remediated efficiently.

180° Ferroelectric Stripe Nanodomains in BiFeO3 Thin Films.

There is growing evidence that domain walls in ferroics can possess emergent properties that are absent in the bulk. For example, 180° ferroelectric domain walls in the ferroelectric-antiferromagnetic BiFeO3 are particularly interesting because they have been predicted to possess a range of intriguing behaviors, including electronic conduction and enhanced magnetization. To date, however, ordered arrays of such domain structures have not been reported. Here, we report the observation of 180° stripe nanodomains in (110)-oriented BiFeO3 thin films grown on orthorhombic GdScO3 (010)O substrates and their impact on exchange coupling to metallic ferromagnets. Nanoscale ferroelectric 180° stripe domains with {112̅} domain walls were observed in films <32 nm thick. With increasing film thickness, we observed a domain structure crossover from the depolarization field-driven 180° stripe nanodomains to 71° ferroelastic domains determined by the elastic energy. These 180° domain walls (which are typically cylindrical or meandering in nature due to a lack of strong anisotropy associated with the energy of such walls) are found to be highly ordered. Additional studies of Co0.9Fe0.1/BiFeO3 heterostructures reveal exchange bias and exchange enhancement in heterostructures based on BiFeO3 with 180° domain walls and an absence of exchange bias in heterostructures based on BiFeO3 with 71° domain walls; suggesting that the 180° domain walls could be the possible source for pinned uncompensated spins that give rise to exchange bias. This is further confirmed by X-ray circular magnetic dichroism studies, which demonstrate that films with predominantly 180° domain walls have larger magnetization than those with primarily 71° domain walls. Our results could be useful to extract the structure of domain walls and to explore domain wall functionalities in BiFeO3.

Simultaneous nitrification and denitrification by novel heterotrophs in remediation of fish processing effluent.

Three isolates viz. Lysinibacillus sp. HT13, Alcaligenes sp. HT15 and Proteus sp. HT37 isolated from fish processing effluent and having a C/N ratio of 2, removed 218, 169, and 400 µg cell(-1) day(-1) NH4(+)-N, respectively without subsequent build up of nitrite or nitrate. Ability of the selected isolates in removing NH4(+)-N, NO2(-)-N, and NO3(-)-N was checked in the presence of four commonly reported and tested effluent carbon sources viz. pyruvate, glycerol, methanol, and acetate. Further, when supplemented to fish processing wastewater containing 234 ppm total Kjeldahl's nitrogen, Lysinibacillus sp. HT13, Alcaligenes sp. HT15, and Proteus sp. HT37 could remediate 95.74, 86.17, and 76.6% nitrogen, respectively in 48 h. This is the first report of a Lysinibacillus sp. carrying out aerobically the process of simultaneous nitrification and denitrification. The results demonstrate the potential of the isolates for use in treatment of fish processing effluents and demonstrating the efficient removal of ammonia.

Real-time observation of local strain effects on nonvolatile ferroelectric memory storage mechanisms.

We use in situ transmission electron microscopy to directly observe, at high temporal and spatial resolution, the interaction of ferroelectric domains and dislocation networks within BiFeO3 thin films. The experimental observations are compared with a phase field model constructed to simulate the dynamics of domains in the presence of dislocations and their resulting strain fields. We demonstrate that a global network of misfit dislocations at the film-substrate interface can act as nucleation sites and slow down domain propagation in the vicinity of the dislocations. Networks of individual threading dislocations emanating from the film-electrode interface play a more dramatic role in pinning domain motion. These dislocations may be responsible for the domain behavior in ferroelectric thin-film devices deviating from conventional Kolmogorov-Avrami-Ishibashi dynamics toward a Nucleation Limited Switching model.

Extramedullary plasmacytoma of the larynx - Case report.

Extramedullary plasmacytoma of the larynx is an extremely rare entity accounting for 0.04-0.45% of malignant tumours of the larynx. The objective of this clinical case report is to highlight the diagnosis and management of a unique case such as this. A 77-year-old gentleman presented with complaints of hoarseness for 1 year. Computed tomography image revealed a soft tissue mass lesion involving the right true vocal cord. Direct laryngoscopic biopsy was performed and subjected to histopathological examination, which showed collection of plasma cells. Immunohistochemistry confirmed the presence of Kappa and Lambda cells. Multiple myeloma (MM) was ruled out. The patient received radical intent radiation therapy using 3DCRT technique with a dose of 50Gy in 25# over 5 weeks. He experienced improvement in hoarseness on subsequent follow-up visits. At 1-year follow up, positron emission tomography computed tomography showed near total resolution of disease with no progression to MM. Radiation therapy alone is known to achieve good local control, recurrence free survival, and organ preservation in such cases.

Machine learning guided rational design of a non-heme iron-based lysine dioxygenase improves its total turnover number.

Highly selective C-H functionalization remains an ongoing challenge in organic synthetic methodologies. Biocatalysts are robust tools for achieving these difficult chemical transformations. Biocatalyst engineering has often required directed evolution or structure-based rational design campaigns to improve their activities. In recent years, machine learning has been integrated into these workflows to improve the discovery of beneficial enzyme variants. In this work, we combine a structure-based machine-learning algorithm with classical molecular dynamics simulations to down select mutations for rational design of a non-heme iron-dependent lysine dioxygenase, LDO. This approach consistently resulted in functional LDO mutants and circumvents the need for extensive study of mutational activity before-hand. Our rationally designed single mutants purified with up to 2-fold higher yields than WT and displayed higher total turnover numbers (TTN). Combining five such single mutations into a pentamutant variant, LPNYI LDO, leads to a 40% improvement in the TTN (218±3) as compared to WT LDO (TTN = 160±2). Overall, this work offers a low-barrier approach for those seeking to synergize machine learning algorithms with pre-existing protein engineering strategies.

Comparative negation of amphiphile production using nutrition factors: Amyloids versus biosurfactants.

Microbial amphiphiles play an important role in environmental activities such as microbial signaling, bioremediation, and biofilm formation. Microorganisms rely on their unique characteristics of interfaces to carry out critical biological functions, which are helped by amphipathic biomolecules known as amphiphiles. Bacillus amyloids aid in cell adhesion and biofilm formation. Pseudomonas sp. are essential in biofilm development and are a vital survival strategy for many bacteria. Furthermore, Pseudomonas and Bacillus are well-known for their ability to produce biosurfactants with a range of applications, including bioremediation and removing biological pollutants from different environments. The study employed 31 different media types and a range of analytical techniques to assess the presence of amyloid proteins and the absence of biosurfactants in Bacillus licheniformis K125 (GQ850525.1) and Pseudomonas fluorescens CHA0. The presence of amyloid proteins was confirmed through Congo red and thioflavin T staining. The carefully constructed medium also efficiently inhibited the synthesis of biosurfactants by these bacteria. Additionally, surface tension measurements, emulsification index, thin-layer chromatography, and high-performance thin-layer chromatography analyses indicated the absence of biosurfactants in the tested media.