Region-Directed Enzyme Immobilization through Engineering Protein Surface with Histidine Clusters.

Enzyme immobilization is a key enabling technology for a myriad of industrial applications, yet immobilization science is still too empirical to reach highly active and robust heterogeneous biocatalysts through a general approach. Conventional protein immobilization methods lack control over how enzymes are oriented on solid carriers, resulting in negative conformational changes that drive enzyme deactivation. Site-selective enzyme immobilization through peptide tags and protein domains addresses the orientation issue, but this approach limits the possible orientations to the N- and C-termini of the target enzyme. In this work, we engineer the surface of two model dehydrogenases to introduce histidine clusters into flexible regions not involved in catalysis, through which immobilization is driven. By varying the position and the histidine density of the clusters, we create a small library of enzyme variants to be immobilized on different carriers functionalized with different densities of various metal chelates (Co2+, Cu2+, Ni2+, and Fe3+). We first demonstrate that His-clusters can be as efficient as the conventional His-tags in immobilizing enzymes, recovering even more activity and gaining stability against some denaturing agents. Furthermore, we find that the enzyme orientation as well as the type and density of the metal chelates affect the immobilization parameters (immobilization yield and recovered activity) and the stability of the immobilized enzymes. According to proteomic studies, His-clusters enable a different enzyme orientation as compared to His-tag. Finally, these oriented heterogeneous biocatalysts are implemented in batch reactions, demonstrating that the stability achieved by an optimized orientation translates into increased operational stability.

Engineered repeat proteins as scaffolds to assemble multi-enzyme systems for efficient cell-free biosynthesis.

Multi-enzymatic cascades with enzymes arranged in close-proximity through a protein scaffold can trigger a substrate channeling effect, allowing for efficient cofactor reuse with industrial potential. However, precise nanometric organization of enzymes challenges the design of scaffolds. In this study, we create a nanometrically organized multi-enzymatic system exploiting engineered Tetrapeptide Repeat Affinity Proteins (TRAPs) as scaffolding for biocatalysis. We genetically fuse TRAP domains and program them to selectively and orthogonally recognize peptide-tags fused to enzymes, which upon binding form spatially organized metabolomes. In addition, the scaffold encodes binding sites to selectively and reversibly sequester reaction intermediates like cofactors via electrostatic interactions, increasing their local concentration and, consequently, the catalytic efficiency. This concept is demonstrated for the biosynthesis of amino acids and amines using up to three enzymes. Scaffolded multi-enzyme systems present up to 5-fold higher specific productivity than the non-scaffolded ones. In-depth analysis suggests that channeling of NADH cofactor between the assembled enzymes enhances the overall cascade throughput and the product yield. Moreover, we immobilize this biomolecular scaffold on solid supports, creating reusable heterogeneous multi-functional biocatalysts for consecutive operational batch cycles. Our results demonstrate the potential of TRAP-scaffolding systems as spatial-organizing tools to increase the efficiency of cell-free biosynthetic pathways.

Using artificial intelligence to reduce orthopedic surgical site infection surveillance workload: Algorithm design, validation, and implementation in 4 Spanish hospitals.

BACKGROUND: Surgical site infection (SSI) surveillance is a labor-intensive endeavor. We present the design and validation of an algorithm for SSI detection after hip replacement surgery, and a report of its successful implementation in 4 public hospitals in Madrid, Spain. METHODS: We designed a multivariable algorithm, AI-HPRO, using natural language processing (NLP) and extreme gradient boosting to screen for SSI in patients undergoing hip replacement surgery. The development and validation cohorts included data from 19,661 health care episodes from 4 hospitals in Madrid, Spain. RESULTS: Positive microbiological cultures, the text variable "infection", and prescription of clindamycin were strong markers of SSI. Statistical analysis of the final model indicated high sensitivity (99.18%) and specificity (91.01%) with an F1-score of 0.32, AUC of 0.989, accuracy of 91.27%, and negative predictive value of 99.98%. DISCUSSION: Implementation of the AI-HPRO algorithm reduced the surveillance time from 975 person/hours to 63.5 person/hours and permitted an 88.95% reduction in the total volume of clinical records to be reviewed manually. The model presents a higher negative predictive value (99.98%) than algorithms relying on NLP alone (94%) or NLP and logistic regression (97%). CONCLUSIONS: This is the first report of an algorithm combining NLP and extreme gradient-boosting to permit accurate, real-time orthopedic SSI surveillance.

Feasibility of Telemedicine in the Management Strategy of Patients With Lymphoma Amid the COVID-19 Pandemic in Spain: Prospective Observational Study.

BACKGROUND: On March 14, 2020, a state of alarm was declared in Spain due to the spread of SARS-CoV-2. Beyond this date, COVID-19 in the country changed the practice of oncologic care. OBJECTIVE: Since recurrent hospital visits were a potential risk factor for contagion, the aim of this prospective observational study was to analyze the consequences of the COVID-19 pandemic in the health care of patients with lymphoma. METHODS: All data were obtained from the electronic medical record. Variables such as age, sex, reason of the visit, use of the patient portal, changes in management, enrollment in clinical trials, and COVID-19 infection were recorded. RESULTS: In all, 290 patients visited the lymphoma clinic, totaling 437 appointments. The median age was 66 (range 18-94) years, and 157 (54.1%) patients were male. Of them, 214 (73.8%) patients had only 1 visit to the clinic. Only 23 (7.9%) patients did not have access to the patient portal. Amid the COVID-19 pandemic, 78 (26.9%) patients remained in active treatment, 35 (12.1%) experienced delays in their treatments, and 6 (2.1%) experienced treatment discontinuation. During the follow-up, only 7 (2.4%) patients had a COVID-19 infection (6 cases with confirmed polymerase chain reaction test and 1 case with clinical suspicion). Despite the implementation of telemedicine strategies to avoid visits to the hospital, 66 (22.8%) patients had in-person visits at the lymphoma clinic. Patients who attended in-person consultations were younger than those who preferred telemedicine consultations (62 vs 66 years; P=.10) and had less use of the patient portal (17/224, 7.6% vs 6/66, 9%; P=.10), although these differences did not reach statistical significance. Patients who attended in-person visits were more likely to have had only 1 visit to the hospital (29/66, 43.9% vs 185/224, 82.6%; P<.001). Regarding the reason of in-person consultations, more patients were on active treatment in comparison to those using telemedicine resources (37/66, 56.1% vs 42/224, 18.3%; P<.001). Patients with a preference for telemedicine strategies had more surveillance visits (147/224, 65.6% vs 24/66, 36.4%; P<.001). Regarding treatment modifications, more treatment delays (29/224, 12.9% vs 6/66, 9.1%; P=.10) and more definite treatment discontinuations (6/224, 2.7% vs 0/66, 0%; P=.10) were seen in patients using telemedicine resources when compared to patients attending in-person visits, although these differences did not reach statistical significance. Regarding the type of therapy, patients attending in-person visits were more likely to receive an intravenous treatment rather than those using telemedicine (23/66, 62.2% vs 17/224, 40.5%; P<.001). CONCLUSIONS: Telemedicine such as patient portals are feasible strategies in the management of patients with lymphoma during the COVID-19 pandemic, with a reduction of in-person visits to the hospital and a very low contagion rate.

Multienzyme Coimmobilization on Triheterofunctional Supports.

Immobilized multienzyme systems are gaining momentum in applied biocatalysis; however, the coimmobilization of several enzymes on one carrier is still challenging. In this work, we exploited a heterofunctional support activated with three different chemical functionalities to immobilize a wide variety of different enzymes. This support is based on agarose microbeads activated with aldehyde, amino, and cobalt chelate moieties that allow a fast and irreversible immobilization of enzymes, enhancing the thermostability of most of the heterogeneous biocatalysts (up to 21-fold higher than the soluble one). Furthermore, this trifunctional support serves to efficiently coimmobilize a multienzyme system composed of an alcohol dehydrogenase, a reduced nicotinamide adenine dinucleotide (NADH) oxidase, and a catalase. The confined multienzymatic system demonstrates higher performance than its free counterpart, achieving a total turnover number (TTN) of 1 × 105 during five batch consecutive cycles. We envision this solid material as a platform for coimmobilizing multienzyme systems with enhanced properties to catalyze stepwise biotransformations.

Cell-Free Biosynthesis of ω-Hydroxy Acids Boosted by a Synergistic Combination of Alcohol Dehydrogenases.

The activity orchestration of an unprecedented cell-free enzyme system with self-sufficient cofactor recycling enables the stepwise transformation of aliphatic diols into ω-hydroxy acids at the expense of molecular oxygen as electron acceptor. The efficiency of the biosynthetic route was maximized when two compatible alcohol dehydrogenases were selected as specialist biocatalysts for each one of the oxidative steps required for the oxidative lactonization of diols. The cell-free system reached up to 100 % conversion using 100 mM of linear C5 diols and performed the desymmetrization of prochiral branched diols into the corresponding ω-hydroxy acids with an exquisite enantioselectivity (ee>99 %). Green metrics demonstrate superior sustainability of this system compared to traditional metal catalysts and even to whole cells for the synthesis of 5-hydroxypetanoic acid. Finally, the cell-free system was assembled into a consortium of heterogeneous biocatalysts that allowed the enzyme reutilization. This cascade illustrates the potential of systems biocatalysis to access new heterofunctional molecules such as ω-hydroxy acids.

Intraparticle Kinetics Unveil Crowding and Enzyme Distribution Effects on the Performance of Cofactor-Dependent Heterogeneous Biocatalysts.

Multidimensional kinetic analysis of immobilized enzymes is essential to understand the enzyme functionality at the interface with solid materials. However, spatiotemporal kinetic characterization of heterogeneous biocatalysts on a microscopic level and under operando conditions has been rarely approached. As a case study, we selected self-sufficient heterogeneous biocatalysts where His-tagged cofactor-dependent enzymes (dehydrogenases, transaminases, and oxidases) are co-immobilized with their corresponding phosphorylated cofactors [nicotinamide adenine dinucleotide phosphate (NAD(P)H), pyridoxal phosphate (PLP), and flavin adenine dinucleotide (FAD)] on porous agarose microbeads coated with cationic polymers. These self-sufficient systems do not require the addition of exogenous cofactors to function, thus avoiding the extensive use of expensive cofactors. To comprehend the microscopic kinetics and thermodynamics of self-sufficient systems, we performed fluorescence recovery after photobleaching measurements, time-lapse fluorescence microscopy, and image analytics at both single-particle and intraparticle levels. These studies reveal a thermodynamic equilibrium that rules out the reversible interactions between the adsorbed phosphorylated cofactors and the polycations within the pores of the carriers, enabling the confined cofactors to access the active sites of the immobilized enzymes. Furthermore, this work unveils the relationship between the apparent Michaelis-Menten kinetic parameters and the enzyme density in the confined space, eliciting a negative effect of molecular crowding on the performance of some enzymes. Finally, we demonstrate that the intraparticle apparent enzyme kinetics are significantly affected by the enzyme spatial organization. Hence, multiscale characterization of immobilized enzymes serves as an instrumental tool to better understand the in operando functionality of enzymes within confined spaces.

YY2 in Mouse Preimplantation Embryos and in Embryonic Stem Cells.

Yin Yang 2 encodes a mammalian-specific transcription factor (YY2) that shares high homology in the zinc finger region with both YY1 and REX1/ZFP42, encoded by the Yin Yang 1 and Reduced Expression Protein 1/Zinc Finger Protein 42 gene, respectively. In contrast to the well-established roles of the latter two in gene regulation, X chromosome inactivation and binding to specific transposable elements (TEs), much less is known about YY2, and its presence during mouse preimplantation development has not been described. As it has been reported that mouse embryonic stem cells (mESC) cannot be propagated in the absence of Yy2, the mechanistic understanding of how Yy2 contributes to mESC maintenance remains only very partially characterized. We describe Yy2 expression studies using RT-PCR and staining with a high-affinity polyclonal serum in mouse embryos and mESC. Although YY2 is expressed during preimplantation development, its presence appears dispensable for developmental progress in vitro until formation of the blastocyst. Attenuation of Yy2 levels failed to alter either Zscan4 levels in two-cell embryos or IAP and MERVL levels at later preimplantation stages. In contrast to previous claims that constitutively expressed shRNA against Yy2 in mESC prohibited the propagation of mESC in culture, we obtained colonies generated from mESC with attenuated Yy2 levels. Concomitant with a decreased number of undifferentiated colonies, Yy2-depleted mESC expressed higher levels of Zscan4 but no differences in the expression of TEs or other pluripotency markers including Sox2, Oct4, Nanog and Esrrb were observed. These results confirm the contribution of Yy2 to the maintenance of mouse embryonic stem cells and show the preimplantation expression of YY2. These functions are discussed in relation to mammalian-specific functions of YY1 and REX1.

Cost-effectiveness of on-site musculoskeletal ultrasound in an outpatient rheumatology clinic.

OBJECTIVE: To evaluate the impact of the routine use of musculoskeletal ultrasound (MSUS) in rheumatology clinics by comparing one clinic with on-site MSUS (REU 1) and four clinics without this resource, which need to refer patients for the MSUS exams (REU 2-5). METHODS: The electronic medical records of all new patients at five rheumatology clinics during a 12-month period were reviewed. The impact of MSUS was analysed by comparing the percentage of direct discharges of patients from the different clinics, as an outcome of effectiveness, and the number and cost of radiology referrals for imaging exams (MSUS and MRI), as an outcome of cost-saving. RESULTS: The medical records of 4923 patients were included in the study, distributed as follows: REU 1, 1464 (29.7%); REU 2, 1042 (21.2%); REU 3, 1089 (22.1%); REU 4, 579 (11.8%); and REU 5, 749 (15.2%). There were more direct discharges from REU 1 (34.4%) than from REU 2-5 (15.6%) (P<0.001). REU 1 made radiological referrals for X-rays, MRIs or MSUS exams in 773 (52.8%) patients, compared with 2626 (75.9%) patients in REU 2-5 (P<0.001). An estimation of costs for the clinical assessment of 1000 new patients revealed a cost-saving in REU 1 of €21 413 in MSUS and of €877 in MRI exams. CONCLUSION: The implementation of on-site MSUS in a new-patient rheumatology clinic is cost-effective, facilitating the direct discharge of patients and reducing the number and cost of radiological referrals for imaging exams.

Pulmonary infectious diseases in patients with primary immunodeficiency and those treated with biologic immunomodulating agents.

PURPOSE OF REVIEW: Lung infectious disease is an important cause of morbidity and mortality in patients with primary immunodeficiencies and other conditions that alter immunologic mechanisms against microbial invasion. Lung infectious diseases occurring in patients with congenital immunodeficiency and patients on treatment with biologic anti-inflammatory compounds are discussed. Understanding of the complex relationships between the immune system and microbes is of paramount importance for timely diagnosis and successful treatment of lung infectious diseases in this group of immunocompromised hosts. RECENT FINDINGS: In the past, only a minority of children with severe primary immunodeficiency survived beyond childhood and these disorders were within the scope of the pediatrician. As modern prophylaxis and treatment strategies have been implemented, these patients will now survive into adulthood. Nowadays, therapy with new biologic compounds--tumor necrosis factor (TNF) blockers and anti-CD20 drugs--that disrupt antimicrobial surveillance and the control of intracellular microorganisms such as mycobacteria, fungi and viruses has been associated with the emergence of a new population at risk for the development of severe pulmonary and disseminated infectious diseases. SUMMARY: A wide array of bacteria, viruses, fungi and protozoa may cause severe pulmonary infectious diseases in patients with primary immunodeficiency and patients on treatment with anti-TNF and anti-CD20 drugs. Knowledge of the association of certain microbial agents with specific immune disturbances is of great clinical interest.