Auxiliary Factors Research Articles

A novel tetratricopeptide-repeat protein, TTP1, forms complexes with glutamyl-tRNA reductase and protochlorophyllide oxidoreductase during tetrapyrrole biosynthesis.

The biosynthesis of the tetrapyrrole end-products chlorophyll and heme depends on a multifaceted control mechanism that acts primarily at the post-translational level upon the rate-limiting step of 5-aminolevulinic acid synthesis and upon light-dependent protochlorophyllide oxidoreductase (POR). These regulatory processes require auxiliary factors that modulate the activity, stability, complex formation, and subplastidal localization of the relevant proteins. Together, they ensure optimal metabolic flow during the day and at night. As an Arabidopsis homolog of the POR-interacting tetratricopeptide-repeat protein (Pitt) first reported in Synechocystis, we characterize tetrapyrrole biosynthesis-regulating tetratricopeptide-repeat protein1 (TTP1). TTP1 is a plastid-localized, membrane-bound factor that interacts with POR, the Mg protoporphyrin monomethylester cyclase CHL27, glutamyl-tRNA reductase (GluTR), GluTR-binding protein, and FLUORESCENCE IN BLUE LIGHT. Lack of TTP1 leads to accumulation of GluTR, enhanced 5-aminolevulinic acid synthesis and lower levels of POR. Knockout mutants show enhanced sensitivity to reactive oxygen species and a slower greening of etiolated seedlings. Based on our studies, the interaction of TTP1 with GluTR and POR does not directly inhibit their enzymatic activity and contribute to the control of 5-aminolevulinic acid synthesis. Instead, we propose that TTP1 sequesters a fraction of these proteins on the thylakoid membrane, and contributes to their stability.

Crop NDVI time series construction by fusing Sentinel-1, Sentinel-2, and environmental data with an ensemble-based framework

Satellite-based Normalized Difference Vegetation Index (NDVI) time series data are conducive for near-real-time (NRT) monitoring of crop progress, but they commonly suffer from data gaps due to cloudy weather conditions. Fortunately, Synthetic Aperture Radar (SAR) data, which are cloud-insensitive, has high potentials to fill these data gaps. However, the relationship between NDVI and SAR data is not generic and affected by various factors (e.g., crop canopy structure and phenology, soil exposure and humidity). Therefore, it is worth exploring to evaluate the relationships and develop a more robust SAR-NDVI fusion method for NDVI time series construction. In this study, we proposed and evaluated an ensemble-based data fusion framework that accounts for these factors, based on which dense NDVI time series for crop monitoring were constructed. The framework consisted of three steps: (1) NDVI was predicted from Sentinel-1 SAR data and auxiliary environmental factors using a random forest (RF) model; (2) an improved feature importance measurement method was proposed to reveal the different contributions of multisource data to the modeling, and suggestions for selecting optimal input parameters were presented; (3) the uncertainty of the predicted data was quantified by an ensemble-based method and incorporated into a Weighted Least Squares (WLS) method to construct dense NDVI time series. Results showed that the RF models were generally improved by the auxiliary data and achieved a satisfactory accuracy of NDVI estimation (R2 > 0.93, RMSE < 0.075) for both corn and soybean crops in Southwestern Ontario, Canada. The proposed method performed well in filling data gaps in both the vegetative and reproductive stages for corn and soybean, providing a practical and promising solution for continuous crop monitoring.

Structures illustrate step-by-step mitochondrial transcription initiation

Transcription initiation is a key regulatory step in gene expression during which RNA polymerase (RNAP) initiates RNA synthesis de novo, and the synthesized RNA at a specific length triggers the transition to the elongation phase. Mitochondria recruit a single-subunit RNAP and one or two auxiliary factors to initiate transcription. Previous studies have revealed the molecular architectures of yeast1 and human2 mitochondrial RNAP initiation complexes (ICs). Here we provide a comprehensive, stepwise mechanism of transcription initiation by solving high-resolution cryogenic electron microscopy (cryo-EM) structures of yeast mitochondrial RNAP and the transcription factor Mtf1 catalysing two- to eight-nucleotide RNA synthesis at single-nucleotide addition steps. The growing RNA–DNA is accommodated in the polymerase cleft by template scrunching and non-template reorganization, creating stressed intermediates. During early initiation, non-template strand scrunching and unscrunching destabilize the short two- and three-nucleotide RNAs, triggering abortive synthesis. Subsequently, the non-template reorganizes into a base-stacked staircase-like structure supporting processive five- to eight-nucleotide RNA synthesis. The expanded non-template staircase and highly scrunched template in IC8 destabilize the promoter interactions with Mtf1 to facilitate initiation bubble collapse and promoter escape for the transition from initiation to the elongation complex (EC). The series of transcription initiation steps, each guided by the interplay of multiple structural components, reveal a finely tuned mechanism for potential regulatory control.

Machine learning based energy demand prediction

Energy demand prediction can benefit electricity consumers, distribution network service providers, and system operators. It heavily depends on auxiliary factors, such as weather parameters (e.g., ambient temperature), which makes this problem more complex. Moreover, for many industrial applications, instead of aiming for the highest prediction accuracy, a more easily understandable and interpretable model that can lead to higher accuracy against the baseline model is the priority. Therefore, this problem still requires more investigation, especially when there is a specified prediction baseline to be compared with. This paper proposes a machine learning (ML) based prediction framework that investigates how temperature combined with energy consumption and simple and interpretable ML methods can be used to provide more precise demand forecasts and thus baselines closer to actual load profiles. The proposed framework is tested on two different real-world energy demand datasets. The analysis shows that using a simple ML model, such as a polynomial regression model, results in a more accurate prediction than the current baselines used in the energy market. The proposed ML models are not black-box type models, and thus are easier to explain and interpret. The ML-based forecasted demand is used as a baseline for demand response (DR) and is compared with the existing baselines used in the demand response market of Australia’s national grid.

A study of auxiliary factors for judges in sentencing dangerous driving offenses - the mediating role of favorable and unfavorable factors.

This paper investigates the ancillary factors judges consider when sentencing dangerous driving offenses. These factors are divided into favorable (i.e., "Confess" [CF], and "Actively compensate and obtain forgiveness from victims" [AC]) and unfavorable categories (i.e., "Mainly or solely responsible for the accident" [MSR], and "Post-accident behavior" [BAA]). Results indicate that both types of factors mediate the relationship between "Blood Alcohol Concentration" (BAC) and the sentencing outcome: favorable factors have a significant negative correlation with sentences, while unfavorable ones show a positive correlation. The mediation effect ratios are 13.8% and 19.1% respectively, with no significant differences between their impacts on judges' sentencing decisions.

Satellite-based estimates of high-resolution CO concentrations at ground level in the Yangtze River Economic Belt of China

This study proposed a method to downscale ground-level CO concentrations from satellite observations. Taking the Yangtze River Economic Belt of China as the study area, ground-level CO concentrations (0.25° × 0.25°) were first estimated from the troposphere (MOPITT) CO columns and atmospheric CO profiles simulated by the chemical transport model CAM-CHEM; then the resulting data was downscaled to 1 × 1 km2 based on an algorithm of multiscale geo-weighted regression (MGWR) model with the auxiliary factors. The estimated ground-level CO concentrations were in good agreement with the observations at ground-based sites (RMSE = 0.25 mg/m3, PRE = 19%). In the Yangtze River Economic Belt, monthly ground-level CO concentrations showed obvious temporal and spatial variations, ranging from 0.30 to 0.81 mg/m3 and an average of 0.49 mg/m3; high CO values occurred in winter, while low in summer; hotspots of CO concentrations were concentrated in the northern Yangtze River Delta and the urban areas.

Efficient degradation of antibiotics by heterojunction photocatalysts driving peroxydisulfate activation under visible light irradiation

Heterogeneous iron materials show potential for activating peroxydisulfate (PDS). However, these systems may be constrained by low efficiency and secondary pollution. The visible-light-assisted activation has been demonstrated as a feasible and effective approach to enhance PDS activation by iron-based materials. In this study, a visible-light-responsive Bi2WO6/Fe2O3 heterojunction photocatalyst was synthesized to improve the ability of Fe2O3 for PDS activation through an effective Fe(III)/Fe(II) cycle. Rapid tetracycline (TC, a common antibiotic) removal (91.7% within 60 min at a concentration of 20 mg·L-1) was achieved in the constructed Bi2WO6/Fe2O3/PDS/vis system under conditions of 0.3 g·L-1 PDS and 0.3 g·L-1 catalyst. The corresponding pseudo-first-order rate constant reached 4.16 × 10-2 min-1, which was 8.42 and 16.38 times higher than those of Bi2WO6/Fe2O3/vis and Bi2WO6/Fe2O3/PDS systems, respectively. Moreover, the Bi2WO6/Fe2O3 exhibited favorable stability and reusability even after five cycles. Lastly, a catalytic mechanism for TC removal and PDS activation was proposed based on quenching experiments and electron spin resonance (ESR) tests. The SO4•- and •OH played a major role in TC removal, while •O2– and 1O2 contributed as auxiliary factors. This study presents a promising strategy for activating PDS using cost-effective and stable Fe(III)-based heterojunctions, and such an idea can be used to design catalysts for other high-value reactions.

Phenotypic and genomic characteristics of oxacillin-susceptible mecA-positive Staphylococcus aureus, rapid selection of high-level resistance to beta-lactams.

The aim of this study is to describe the phenotypic and genetic properties of oxacillin-susceptible methicillin-resistant Staphylococcus aureus (OS-MRSA) isolates and their beta-lactam resistant derivatives obtained after selection with oxacillin. A collection of hospital- (HA-) and community-acquired (CA-) MRSA was screened for oxacillin susceptibility. Antibiotic susceptibility testing, population analysis profile (PAP), mecA expression analysis, and whole genome sequencing (WGS) were performed for 60 mecA-positive OS-MRSA isolates. Twelve high-level beta-lactam resistant derivatives selected during PAP were also subjected to WGS. OS-MRSA were more prevalent among CA-MRSA (49/205, 24%) than among HA-MRSA (11/575, 2%). OS-MRSA isolates belonged to twelve sequence types (ST), with a predominance of ST22-t223-SCCmecIVc and ST59-t1950-SCCmecV lineages. OS-MRSA were characterized by mecA promoter mutations at - 33 (C→T) or - 7 (G→T/A) along with PBP2a substitutions (S225R or E246G). The basal and oxacillin-induced levels of mecA expression in OS-MRSA isolates were significantly lower than those in control ST8-HA-MRSA isolates. Most of the OS-MRSA isolates were heteroresistant to oxacillin. High-level beta-lactam resistant OS-MRSA derivatives selected with oxacillin carried mutations in mecA auxiliary factors: relA (metabolism of purines), tyrS, cysS (metabolism of tRNAs), aroK, cysE (metabolism of amino acids and glycolysis). Cefoxitin-based tests demonstrated high specificity for OS-MRSA detection. The highest positive predictive values (PPV > 0.95) were observed for broth microdilution, the VITEK® 2 automatic system, and chromogenic media. Susceptibility testing of CA-MRSA requires special attention due to the high prevalence of difficult-to-detect OS-MRSA among them. Mis-prescription of beta-lactams for the treatment of OS-MRSA may lead to selection of high-level resistance and treatment failures.

Chloroplast Ribosome Biogenesis Factors.

The formation of chloroplasts can be traced back to an ancient event in which a eukaryotic host cell containing mitochondria ingested a cyanobacterium. Since then, chloroplasts have retained many characteristics of their bacterial ancestor, including their transcription and translation machinery. In this review, recent research on the maturation of rRNA and ribosome assembly in chloroplasts is explored, along with their crucial role in plant survival and their implications for plant acclimation to changing environments. A comparison is made between the ribosome composition and auxiliary factors of ancient and modern chloroplasts, providing insights into the evolution of ribosome assembly factors. Although the chloroplast contains ancient proteins with conserved functions in ribosome assembly, newly evolved factors have also emerged to help plants acclimate to changes in their environment and internal signals. Overall, this review offers a comprehensive analysis of the molecular mechanisms underlying chloroplast ribosome assembly and highlights the importance of this process in plant survival, acclimation and adaptation.

Patient Perspectives on Virtual Care for Diabetes Management in the Era of COVID-19

ObjectiveThe aim of this study was to characterize patient perspectives on the quality of diabetes care at The Ottawa Hospital Endocrinology and Metabolism multidisciplinary clinic delivered virtually during the COVID-19 pandemic. MethodsAn online survey was developed to collect quantitative and qualitative data on patients’ experiences with virtual diabetes clinic visits between March 2020 and April 2021. ResultsA total of 333 patients were included in this study; 45% were female and had a mean age of 60 years. Seventy-nine percent were born in Canada and 87% identified as Caucasian. Thirty-six percent were treated for type 1 diabetes and 62% for type 2 diabetes. Eighty-seven percent of virtual visits occurred by phone, with 12% of these on Zoom. Overall, 83% were “very satisfied” or “satisfied” with their virtual care experience. Most respondents perceived all treatment-related factors to be equally well addressed virtually as in person, except for physical examination. Auxiliary factors like travel, cost, and time spent were rated more favourably with virtual care. Qualitative findings provided further contextualization and identified gaps in virtual care delivery. For future visits, 44% wanted in-person visits only as needed, 36% wanted a hybrid of in-person and virtual appointments, and 11% preferred in-person appointments only. ConclusionsPatients perceive that virtual care provides high-fidelity diabetes management while reducing their pandemic risks as well as minimizing travel and time associated with in-person care. Virtual care is an important medium for diabetes care delivery that should be used according to patient preference and intermixed with in-person appointments.

Spatial Pattern and Drivers of China’s Public Cultural Facilities between 2012 and 2020 Based on POI and Statistical Data

In the context of globalization and the intensification of international competition, the construction of public cultural facilities has long been not limited to meeting the cultural needs of the people but has become an important initiative to shape the competitiveness of cities. This paper collected POI and socio-economic statistics from 2012 to 2020 from 285 Chinese cities and employed the coefficient of variation (CV), Gini index (GI), ESDA, and GeoDetector to analyze the spatial patterns and driving mechanisms of public cultural facilities. Findings: (1) Public cultural facilities in Chinese cities were featured by evident regional gradient differences and uneven spatial distributions, with a CV greater than 1.3 and a GI greater than 0.5 in both years. They also showed signs of aggregation at weak levels, with a Moran I of 0.15 in both years and a cluster pattern of “hot in the east and cold in the west”. (2) Different types of public cultural facilities had differences in their differentiation, aggregation, and change trends. The CV changed from 1.39~2.69 to 1.06~1.92, and the GI changed from 0.53~0.80 to 0.47~0.62, with the differentiation of libraries, museums, theaters, art galleries, and cultural centers decreasing gradually, while that of exhibition halls increased day by day. As the Moran I increased from 0.08~0.20 to 0.12~0.24, libraries, museums, art galleries, and cultural centers showed weak aggregation with an increasingly strong trend. Theaters and exhibition halls also showed weak aggregation but in a declining trend, with the Moran I changing from 0.15~1.19 to 0.09~0.1. (3) The five driving variables exhibit significant differences in their strength across time and across regions, with the economic and infrastructure factors being the strongest and the urbanization factor the weakest. There are significant differences in the strength of the driving forces among the factors, with the total retail sales of consumers, the number of subscribers to internet services, regular higher education institutions, and undergraduates in regular HEIs playing both direct and interactive roles as the core factors. (4) The 285 cities in China are divided into four policy zonings of star, cow, question, and dog cities. Star cities should maintain their status quo without involving too much policy intervention, whereas the core and important factors should be the focus of policy in dog cities and cow cities, and the auxiliary factors should be the focus of policy in question cities. This paper contributes to the in-depth knowledge of the development pattern of public cultural facilities and provides a more refined basis for the formulation of public cultural facility promotion policies in China and similar countries.

Data-Driven Models Informed by Spatiotemporal Mobility Patterns for Understanding Infectious Disease Dynamics

Data-driven approaches predict infectious disease dynamics by considering various factors that influence severity and transmission rates. However, these factors may not fully capture the dynamic nature of disease transmission, limiting prediction accuracy and consistency. Our proposed data-driven approach integrates spatiotemporal human mobility patterns from detailed point-of-interest clustering and population flow data. These patterns inform the creation of mobility-informed risk indices, which serve as auxiliary factors in data-driven models for detecting outbreaks and predicting prevalence trends. We evaluated our approach using real-world COVID-19 outbreaks in Beijing and Guangzhou, China. Incorporating the risk indices, our models successfully identified 87% (95% Confidence Interval: 83–90%) of affected subdistricts in Beijing and Guangzhou. These findings highlight the effectiveness of our approach in identifying high-risk areas for targeted disease containment. Our approach was also tested with COVID-19 prevalence data in the United States, which showed that including the risk indices reduced the mean absolute error and improved the R-squared value for predicting weekly case increases at the county level. It demonstrates applicability for spatiotemporal forecasting of widespread diseases, contributing to routine transmission surveillance. By leveraging comprehensive mobility data, we provide valuable insights to optimize control strategies for emerging infectious diseases and facilitate proactive measures against long-standing diseases.

Endogenous Adenosine Triphosphate-Assisted Three-Dimensional DNA Walker Assembled on Soft Nanoparticles for Intracellular MicroRNA Imaging.

DNA walkers, a sophisticated type of nanomachines, exhibit intelligent application in biosensing with high programmability and flexibility but usually need additional auxiliary driving force, particularly when walking on hard surfaces. Herein, we construct a three-dimensional (3D) DNA walker on the soft surface of DNA nanospheres (DSs) by using a single-stranded DNA (ssDNA), which is powered by endogenous adenosine triphosphate (ATP) of live cells, so as to sensitively image microRNA (miRNA) in the tumor microenvironment. When the DS walker enters into live cells, miR-21, a general overexpressed biomarker in cancer cells, binds with the blocking strand (B), releasing the walking strand (W) and triggering an ATP-propelled walking reaction. The walking of the DS walker then generates an increasing Cy3 fluorescence signal that indicates the content of miR-21 with about 2.73-fold increase in sensitivity and about 157-fold decrease in the detection limit. Notably, the assembly of the DS walker on soft nanoparticles needs just an easy hybridization process, which facilitates the operation. Meanwhile, this endogenous ATP-powered 3D DNA walker walking on the soft surface performs real-time in situ imaging of miR-21 in live cells, which not only avoids the complex cell treatment and signal error induced by additional auxiliary factors, but also shows high promise of designing programmable DNA nanomachines.

SKI complex: A multifaceted cytoplasmic RNA exosome cofactor in mRNA metabolism with links to disease, developmental processes, and antiviral responses.

RNA stability and quality control are integral parts of gene expression regulation. A key factor shaping eukaryotic transcriptomes, mainly via 3'-5' exoribonucleolytic trimming or degradation of diverse transcripts in nuclear and cytoplasmic compartments, is the RNA exosome. Precise exosome targeting to various RNA molecules requires strict collaboration with specialized auxiliary factors, which facilitate interactions with its substrates. The predominant class of cytoplasmic RNA targeted by the exosome are protein-coding transcripts, which are carefully scrutinized for errors during translation. Normal, functional mRNAs are turned over following protein synthesis by the exosome or by Xrn1 5'-3'-exonuclease, acting in concert with Dcp1/2 decapping complex. In turn, aberrant transcripts are eliminated by dedicated surveillance pathways, triggered whenever ribosome translocation is impaired. Cytoplasmic 3'-5' mRNA decay and surveillance are dependent on the tight cooperation between the exosome and its evolutionary conserved co-factor-the SKI (superkiller)complex (SKIc). Here, we summarize recent findings from structural, biochemical, and functional studies of SKIc roles in controlling cytoplasmic RNA metabolism, including links to various cellular processes. Mechanism of SKIc action is illuminated by presentation of its spatial structure and details of its interactions with exosome and ribosome. Furthermore, contribution of SKIc and exosome to various mRNA decay pathways, usually converging on recycling of ribosomal subunits, is delineated. A crucial physiological role of SKIc is emphasized by describing association between its dysfunction and devastating human disease-a trichohepatoenteric syndrome (THES). Eventually, we discuss SKIc functions in the regulation of antiviral defense systems, cell signaling and developmental transitions, emerging from interdisciplinary investigations. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Turnover and Surveillance > Regulation of RNA Stability RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.

Phosphoregulation of DNA repair via the Rad51 auxiliary factor Swi5–Sfr1

Homologous recombination (HR) is a major pathway for the repair of DNA double-strand breaks, the most severe form of DNA damage. The Rad51 protein is central to HR, but multiple auxiliary factors regulate its activity. The heterodimeric Swi5-Sfr1 complex is one such factor. It was previously shown that two sites within the intrinsically disordered domain of Sfr1 are critical for the interaction with Rad51. Here, we show that phosphorylation of five residues within this domain regulates the interaction of Swi5-Sfr1 with Rad51. Biochemical reconstitutions demonstrated that a phosphomimetic mutant version of Swi5-Sfr1 is defective in both the physical and functional interaction with Rad51. This translated to a defect in DNA repair, with the phosphomimetic mutant yeast strain phenocopying a previously established interaction mutant. Interestingly, a strain in which Sfr1 phosphorylation was blocked also displayed sensitivity to DNA damage. Taken together, we propose that controlled phosphorylation of Sfr1 is important for the role of Swi5-Sfr1 in promoting Rad51-dependent DNA repair.

Human Tim8a, Tim8b and Tim13 are auxiliary assembly factors of mature Complex IV.

Human Tim8a and Tim8b are paralogous intermembrane space proteins of the small TIM chaperone family. Yeast small TIMs function in the trafficking of proteins to the outer and inner mitochondrial membranes. This putative import function for hTim8a and hTim8b has been challenged in human models, but their precise molecular function(s) remains undefined. Likewise, the necessity for human cells to encode two Tim8 proteins and whether any potential redundancy exists is unclear. We demonstrate that hTim8a and hTim8b function in the assembly of cytochrome c oxidase (Complex IV). Using affinity enrichment mass spectrometry, we define the interaction network of hTim8a, hTim8b and hTim13, identifying subunits and assembly factors of the Complex IV COX2 module. hTim8-deficient cells have a COX2 and COX3 module defect and exhibit an accumulation of the Complex IV S2 subcomplex. These data suggest that hTim8a and hTim8b function in assembly of Complex IV via interactions with intermediate-assembly subcomplexes. We propose that hTim8-hTim13 complexes are auxiliary assembly factors involved in the formation of the Complex IV S3 subcomplex during assembly of mature Complex IV.

Robust regulation of transcription pausing in Escherichia coli by the ubiquitous elongation factor NusG

Transcription elongation by multi-subunit RNA polymerases (RNAPs) is regulated by auxiliary factors in all organisms. NusG/Spt5 is the only universally conserved transcription elongation factor shared by all domains of life. NusG is a component of antitermination complexes controlling ribosomal RNA operons, an essential antipausing factor, and a transcription-translation coupling factor in Escherichia coli. We employed RNET-seq for genome-wide mapping of RNAP pause sites in wild-type and NusG-depleted cells. We demonstrate that NusG is a major antipausing factor that suppresses thousands of backtracked and nonbacktracked pauses across the E. coli genome. The NusG-suppressed pauses were enriched immediately downstream from the translation start codon but were also abundant elsewhere in open reading frames, small RNAgenes, and antisense transcription units. This finding revealed a strong similarity of NusG to Spt5, which stimulates the elongation rate of many eukaryotic genes. We propose a model in which promoting forward translocation and/or stabilization of RNAP in the posttranslocation register by NusG results in suppression of pausing in E. coli.

EFFECT OF A COMPLEX ACTION OF OZONETHERAPY COMBINED WITH AUTOLOGOUS PLATELET-RICH PLASMA APPLICATION ON THE CHARACTER OF MORPHOFUNCTIONAL CHANGES OF THE TISSUE MACROPHAGES IN PATIENTS WITH DIABETIC FOOT SYNDROME

Summary. Objective: to study the character of ultrastructural changes in the tissue macrophages under the effect of a complex of auxiliary factors promoting reparative process activation in the wound including ozonetherapy, local application of autologous platelet-rich plasma (PRP) and vacuum therapy.&#x0D; Materials and methods. The patients examined were divided into three groups. The first group included 23 (32,85%) patients who were treated by means of regional ozone therapy. The second group included 23 (32,85%) patients treated by means of local PRP therapy. The control group included 24 (34,28%) patients who during the postoperative period received a complex of therapeutic measures according to the generally accepted method.&#x0D; Results. Stimulation of the macrophage functional activity under ozone effect with destructive changes found in the cells without necrotizing damage was found tobe explained by apoptosis mechanism involvement as a positive factor in the regulation of local homeostasis on completion of inflammatory (exudative) phase of the wound process.&#x0D; Conclusions. A complex of such auxiliary therapeutic measures confirm more determined level of the reparative process activation on the level of the tissue macrophages in both groups examined (№ 1 and №2) in comparison with the control one.&#x0D; Prospects of further research. The results obtained confirm and determine further necessity to carry out search in novations in the treatmen to diabetic foot syndrome using the factors of physical and biological effect directed to the activation of the wound reparative process.

Discovery of the novel auxiliary factor for β-lactam resistance BlrA in community-acquired methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important human pathogens that cause a variety of infections in community and hospital settings. This organism displays high levels of resistance to β-lactam antibiotics and this principally occurs due to the production of β-lactamase and the penicillin binding protein PBP2a encoded by mecA gene. Furthermore, additional mechanisms, such as auxiliary factors, significantly contribute to β-lactam resistance. However, the function of most of these factors is still unknown.&#x0D; Recently, in our laboratory, the novel auxiliary factor gene blrA was initially identified by transposon mutagenesis in the community-acquired MRSA strain JE2. Next, the transposon mutation was transduced to the community-acquired MRSA strain MW2, resulting in the formation of a transposon mutant for blrA (blrA::ermB), denoted as MW2A. Initially, our results suggested that MW2A is more susceptible to oxacillin than the MW2 wild-type. Then, we performed the Minimum Inhibitory Concentration (MIC) method for the β-lactam antibiotics: oxacillin, cefoxitin, cephradine, ceftazidime, cefaclor and imipenem. MW2A exhibited a two-fold reduction for all tested β-lactam antibiotics compared to the MRSA wild-type strain MW2. Additionally, no phenotypical changes were observed after performing PBP2a latex agglutination test and phage spot assay. Finally, using DeepTMHMM we show that BlrA is likely to act intracellularly, which is typical of auxiliary factors.&#x0D; In this study, we show that BlrA is clearly involved in β-lactam resistance, but does not affect the expression of the gene mecA or the structure of the wall teichoic acids. Furthermore, we propose that that BlrA acts as an auxiliary factor and is activated in response to antimicrobial stress.

In silico identification of auxiliary factors genes required for β-lactam resistance

Staphylococcus aureus is a type of bacteria commonly found on the skin and in the nasal passages of healthy individuals. However, it can also cause a range of infections in clinical settings. One of the most concerning aspects of S. aureus is its ability to develop antibiotic resistance. Methicillin-resistant S. aureus (MRSA) is a strain of the bacteria that is resistant to many antibiotics and can be difficult to treat. The primary mechanism of methicillin resistance in MRSA is the presence of the mecA gene, which encodes for a modified penicillin-binding protein known as PBP2a. This protein has a lower affinity for β-lactam antibiotics. Another gene, blaZ, is also present in MRSA and encodes for a β-lactamase enzyme that can hydrolyse and inactivate β-lactam antibiotics such as penicillin. In addition, there are several auxiliary factors that can contribute to β-lactam resistance. They can include efflux pumps, enzymes that modify or degrade antibiotics, and bacterial cell wall modifications that reduce the affinity of antibiotics for their targets. In this study, with the aid of the in silico identification method, we identify the novel auxiliary factors aux1, aux2, aux4, aux11, aux14, aux16 and aux19. Next, we show that aux2, aux4, aux11, aux14 are not directly involved in β-lactam resistance, but may contribute through other mechanisms that decrease the efficacy of these antibiotics, whereas aux16 and aux19 are directly associated with β-lactam and bacitracin resistance, respectively. Understanding the various auxiliary factors that contribute to beta-lactam resistance can help guide the development of new antibiotics and other therapeutic strategies.