Strain Profiles Research Articles

Microalgae-Assisted Treatment of Wastewater Originating from Varied Sources, Particularly in the Context of Heavy Metals and Antibiotic-Resistant Bacteria

The increasing prevalence of heavy metals and antibiotic-resistant bacteria in wastewater (WW) raises serious environmental and public health concerns. This study investigates the efficiency of the microalgal strain Chlorella vulgaris EV-465 in treating wastewater and evaluates the antibiotic resistance profile of bacterial strains obtained from WW samples. Chlorella vulgaris EV-465 was used to treat four types of wastewater—domestic, municipal, hospital, and industrial wastewater—through 21 days of incubation. The findings demonstrated pH stabilization and significant decreases in nutrients (total nitrogen—TN, total phosphorus—TP), biological oxygen demand (BOD), chemical oxygen demand (COD), heavy metal (HM) concentrations, and bacterial count. Copper (Cu) showed the highest reduction, decreasing by 80% in industrial wastewater within 14 days, while lead (Pb) proved more resistant to removal, with only a 50% decrease by day 21. Additionally, the algae decreased bacterial counts, lowering colony-forming units (Log CFU/mL) from 9.04 to 4.65 in municipal wastewater over the 21-day period. Antibiotic susceptibility tests for isolated bacterial strains revealed high levels of resistance, with seven out of nine bacterial strains exhibiting multidrug resistance. Notably, Enterococcus faecium (PBI08), Acinetobacter baumannii (YBH19), and Pseudomonas aeruginosa (NBH16) displayed resistance to all nine antibiotics tested. Among the tested antibiotics, Ciprofloxacin showed the highest efficacy, with 66% susceptibility of tested bacterial strains. Cluster and phylogenetic analyses showed that the majority of the isolated bacterial strains belonged to the genera Pseudomonas and Escherichia, highlighting their genetic diversity and varied resistance mechanisms.

Partial replacement of soybean with local alternative sources: effects on behavior, cecal microbiota, and intestinal histomorphometry of local chickens

Interest in partially replacing soybean meal in poultry diets with alternative protein sources such as agri-industrial by-products and black soldier fly (BSF, Hermetia illucens) has gained significant attention due to sustainability concerns. This study aimed to evaluate the effects of broiler diets in which soybean meal was partially substituted with agri-industrial by-products with or without BSF larvae meal, on the behavior, intestinal histomorphometry, and microbiome profile of a local broiler chicken strain. There were three dietary treatments. (1) A corn-soybean-based diet (Control), (2) a diet in which soybean was partly replaced (SPR) with local agri-industrial by-products, namely sunflower meal, brewers' dried grain, and wheat middlings, and (3) a diet in which BSF (5%) meal was added to SPR (SPR+BSF). Behavior was recorded on days 14, 35, and 49 at the pen level. On day 55, intestinal segments and cecal contents were collected from eight chickens per pen for histomorphometry and microbiome analysis. Dietary manipulations did not affect the behavior of broiler chickens (P > 0.05) suggesting that the experimental diets had no influence on behavior. A significant interaction between the intestinal segment and diets revealed that the SPR and SPR+BSF diets decreased duodenal villus height (VH) compared to the control diet (P < 0.05). However, this effect was not consistent across all of intestinal segments. Diet did not affect villus height to crypt depth ratio (VH/CD; P > 0.05), indicating no significant impact on the absorptive capacity of the digestive system. Firmicutes and Bacteroidetes were the dominant phyla in the cecal samples. Colidextribacter and Oscillibacter spp. were more abundant in chickens fed the SPR diet compared to those fed the control diet. The SPR+BSF diet resulted in higher abundance of Rikenella and Colidextribacter spp. compared to the control diet, while Desulfovibrio, Ruminococcus torques group, and Lachnoclostridium were more abundant in the ceca of birds fed the SPR diet than those fed SPR+BSF. In conclusion, replacement of soybean with agri-industrial by-products and BSF larvae meal could regulate the cecal microbiota composition without negatively affecting the behavior and intestinal histomorphometry of the local chickens.

Bridging the Gap: linking Torulaspora delbrueckii Genotypes to Fermentation Phenotypes and Wine Aroma.

Climate change and consumer preferences are driving innovation in winemaking, with a growing interest in non-Saccharomyces species. Among these, Torulaspora delbrueckii (Td) has gained recognition for its ability to reduce volatile acidity and enhance aromatic complexity in wine. However, knowledge regarding its phenotypic and genomic diversity impacting alcoholic fermentation remains limited. Aiming to elucidate the metabolic differences between Td and Saccharomyces cerevisiae (Sc) and the Td intraspecies diversity, we conducted a comprehensive metabolic characterization of fifteen Td strains. This analysis delved beyond standard fermentation parameters (kinetics and major metabolites production) to explore non-conventional aromas and establish genotype-phenotype links. Our findings confirmed that most Td strains produce less acetic acid and more succinate and glycerol than Sc. The overall aromatic profiles of Td strains differed from Sc, exhibiting higher levels of monoterpenes and higher alcohols, while producing less acetate esters, fatty acids, their corresponding ethyl esters, and lactones. Moreover, we identified the absence of genes responsible for specific aroma profiles, such as decreased ethyl esters production, as well as the absence of cell wall genes, which might negatively affect Td performance when compared to Sc. This work highlights the significant diversity within Td and underscores potential links between its genotype and phenotype.

Distributed Backface Strain Sensing of Composite Adhesively Bonded Joints under Mode II Fatigue Loading

When investigating the fracture behaviour of adhesive joints, accurate crack tip localization is under mode II loading is particularly challenging due to the absence of crack opening. The crack front often has a curved shape, so methods that inspect the side of the specimen cannot capture the crack length throughout its width. In this study, distributed backface strain sensing using Optical Backscatter Reflectometry fibre sensors is used to monitor fatigue crack growth in adhesively bonded composite End Notched Flexure Specimens. The obtained backface strain profiles were compared with analytical and Finite Element solutions to understand their relationship with the crack length. Results show that the crack tip position can be found by a local extremum in the first derivative of the strain profile. The proposed monitoring technique was compared with more established techniques for crack length measurement, such as Visual Testing, Compliance Monitoring, and Phased Array Ultrasonic Testing, and was shown to provide good accuracy. The evaluation of these techniques not only plays a crucial role in ensuring accurate testing, but can also contribute to the development of effective strategies for inspection and monitoring of adhesive joints.

Characterization of a Highly Virulent Klebsiella michiganensis Strain Isolated from a Preterm Infant with Sepsis.

Klebsiella michiganensis is an opportunistic pathogen that causes an increasing number of serious infections. This study aimed to investigate the etiology of the severe clinical symptoms of sepsis in preterm infants and the characterization of K. michiganensis isolates. Whole-genome sequencing (WGS) was performed on three strains isolated from an infected preterm infant. Additionally, the genomic sequences of 534 K. michiganensis strains were obtained from the NCBI database. To gain deeper insights into these strains, we utilized the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG), and Pathogen Host Interactions (PHI) database annotation tools for comprehensive gene function analyses. Moreover, the multilocus sequence typing (MLST), EasyCGtree, and virulence factor database (VFDB) were employed to determine the sequence types (STs), construct phylogenetic trees, and identify potential virulence factors. Sequence analysis found that the three isolated strains had identical sequence characteristics and did not correspond to any of the known ST types. Virulence factor analysis revealed that the three strains harbored mrkABCDFHIJ, fimABCDEFGHIK, entABCDEFS, fepABCD, and capsule genes. These virulence factors are likely to play crucial roles in enhancing adhesion and metabolic capabilities, resisting phagocytosis (inducing immune cell damage), and ultimately contributing to prolonged bacteremia. The phylogenetic tree and comparative genomics of virulence factors showed the genetic and virulence factor diversity of the currently reported K. michiganensis strains. We identified a novel strain of K. michiganensis that exhibits high virulence and leads to severe septicemia phenotypes in preterm infants. Furthermore, comparative genomic analysis of previously reported K. michiganensis strains revealed the existence of three clades. This comprehensive analysis provides novel insights into the genetic relationships and virulence factor profiles of diverse strains of K. michiganensis. In future, it will be necessary to investigate the concept of the high virulence of K. michiganensis to determine the treatment method.

Profile of digital eye strain in teachers of different professions.

Profile of digital eye strain in teachers of different professions.

Comparative Proteome-Wide Abundance Profiling of Yeast Strains Deleted for Cdc48 Adaptors

The yeast ATPase Cdc48 (known as p97/VCP in human cells) plays an important role in the Ubiquitin Proteasome System. VCP is essential for cancer cell proliferation, and its dysregulation has been implicated in several neurodegenerative diseases. Cdc48 functions by extracting ubiquitylated proteins from membranes, protein complexes and chromatin by often facilitating their proteasomal degradation. Specific adaptors or cofactors, primarily belonging to the UBX domain-containing protein family (which has seven members in Saccharomyces cerevisiae) recruit Cdc48 to ubiquitylated proteins. Here, we employed sample multiplexing-based quantitative mass spectrometry to profile global protein abundance in p97 adaptor deletion strains, specifically comparing seven single deletion strains of UBX domain-containing proteins and the Cuz1 deletion strain, which belongs to the zinc finger AN1-type domain protein family. We observed that each strain showed unique sets of differentially abundant proteins compared to the wild type. Our analysis also revealed a role for Ubx3 in maintaining wild type levels of mitochondrial proteins. Overall, we identified ~1400 differentially abundant proteins in the absence of a specific Cdc48 adaptor. This unique dataset offers a valuable resource for studying the functions of these adaptors, aiming to achieve a better understanding of the cellular processes regulated by Cdc48 itself and to deepen our understanding of the Ubiquitin Proteasome System.

The detection and utilization of volatile metabolomics in Klebsiella pneumoniae by gas chromatography-ion mobility spectrometry

This research aimed to analyze the volatile compounds emitted during the proliferation of Klebsiella pneumoniae (K. pneumoniae) in the laboratory setting using gas chromatography-ion mobility spectrometry (GC-IMS) and to investigate the potential of volatile metabolomics for detecting carbapenemase-producing strains of K. pneumoniae. The volatile metabolomics of K. pneumoniae were comprehensively analyzed using GC-IMS in tryptic soy broth (TSB) as the culture medium. Afterward, the growth stabilization period (T2) served as the primary time point for analysis, with the introduction of imipenem and carbapenemase inhibitors (avibactam sodium or EDTA) during the exponential growth phase (T0) to further investigate alterations in volatile molecules associated with K. pneumoniae. Standard strains were utilized as references, while clinical strains were employed for validation purposes. At T2, a total of 22 volatile organic compounds (VOCs) associated with K. pneumoniae were identified (3 VOCs found in both monomer and dimer forms). Significant differences in VOCs were observed between carbapenemase-negative and carbapenemase-positive strains, both standard and clinical, following the introduction of imipenem. Furthermore, the addition of avibactam sodium led to distinct changes in the VOC content of strains producing class A carbapenemase, while the addition of EDTA resulted in specific alterations in the volatile metabolic profiles of strains producing class B carbapenemase. GC-IMS demonstrated significant promise for analyzing bacterial volatile metabolomics, and its application in evaluating the volatolomics of K. pneumoniae may facilitate the timely detection of carbapenemase-producing strains.

Differences in cardiac magnetic resonance imaging bi-atrial strain between elite athletes and atrial fibrillation patients

Abstract Background Elite athletes frequently demonstrate outspoken bi-atrial dilation, even exceeding volumes seen in patients with atrial fibrillation (AF). Hence, distinguishing atrial exercise-induced adaptation from maladaptation or atrial pathology cannot be done using volumes only. However, data on bi-atrial strain in athletes compared with AF patients investigated using cardiac magnetic resonance imaging (CMR). Methods We performed a retrospective cross-sectional analysis of CMR data comparing three groups: (1) elite athletes included in the ELITE-cohort at the Amsterdam UMC (> 16 years of age and train ≥ 10 hours/week at (inter)national or Olympic level, (2) paroxysmal- (PAF) and persistent AF patients awaiting PVI and (3) healthy controls. All participants underwent CMR in sinus rhythm. Left- and right atrial (LA/RA) reservoir (RES), conduit (CD) and contractile (CT) strain were analysed by automatic feature tracking (FT). Results We included a total of 340 elite athletes (median age 28 years [17, 67]; female n=145 (42.6%)), 103 AF patients (median age 60 [29, 75], female n=36 (35%), PAF n=74 (71.8%), persistent AF n=29 (28.2%), and 85 healthy controls (median age 28 [16, 72], female n=39 (45.9%). Elite athletes had similar indexed maximal left atrial volumes (LAVI) compared to AF patients (49.6 ml/m2 [41.9, 58.3] vs 47.9 ml/m2 [40.5 ml/m2], p = .25), but larger indexed maximal right atrial volumes (RAVI) (59.3 ml/m2 [50.7, 70.7] vs 44.7 ml/m2 [37.0, 55.7], p < .001). Elite athletes had lower LA RES strain (42.8% [36.7. 49.2]) than controls (47.5% [40.6, 54.3], p < .001) but a higher LA RES than AF patients (34.7% [27.4, 41.6], p < .001). Athletes demonstrated higher LA CD/CT ratio (2.2 [1.8, 2.8]) than healthy controls (1.8 [1.4, 2.2], p < .001) and AF patients (1.4 [1.1, 1.9], p < .001) caused by a higher LA CD in athletes (29.2% [24.7, 34.2] compared to healthy controls (29.1% [24.0, 36.2], p < .001) and AF patients (20.1% [16.2, 25.6], p < .001) and a lower LA CT in both athletes (13.0% [22.1, 15.8] and controls (20.1% [16.2, 25.6], compared to healthy controls (17.2% [14.1, 19.9], p < .001). Elite athletes had lower RA RES strain (51.5% [42.8. 63.4]) than controls (57.3% [48.0, 73.5], p = .001) and higher RA RES than AF patients (44.7% [34.1, 55.0], p < .001). AF patients had lower RA CD (28.3% [20.1, 36.8] than elite athletes (35.9% [28.9, 45.5], p < .001) and healthy controls (41.9% [32.4, 51.1], p < .001). Elite athletes had higher RA CD/CT ratio than AF patients (2.5 [1.9, 3.2] vs 1.9 [1.2, 2.4], p < .001). Conclusion Compared with healthy controls and patients with AF, athletes demonstrate unique bi-atrial characteristics. While LAVI is similar in both elite athletes and AF patients, elite athletes demonstrate larger RAVI and a unique strain profile characterized by a higher bi-atrial CD/CT ratio compared with AF patients, but a reduced bi-atrial RES strain relative to healthy controls yet elevated compared to AF patients.Differences in bi-atrial strain

Luteibacter sahnii sp. nov., A Novel Yellow-Colored Xanthomonadin Pigment Producing Probiotic Bacterium from Healthy Rice Seed Microbiome.

To explore the rice seed microbiome, our objective was to isolate novel strains of Xanthomonas, a plant-associated bacterium with diverse lifestyles. Four isolates, anticipated to be Xanthomonas based on morphological features of yellow colonies, were obtained from healthy rice seeds. Phylo-taxono-genomic analysis revealed that these isolates formed monophyletic lineages belonging to a novel species within the genus Luteibacter. Pairwise ortho Average Nucleotide Identity and digital DNA-DNA hybridization confirmed their distinct species status. We propose Luteibacter sahnii sp. nov. as a novel species, with PPL193T = MTCC 13290T = ICMP 24807T = CFBP 9144T as the type strain and PPL201, PPL552, and PPL554 as other constituent members. The fatty acid profile of the type strain is dominated by branched fatty acids like Iso-C15:0, consistent with other members of the genus. The novel species displays non-pathogenic attributes and exhibits plant probiotic properties, protecting rice plants from the leaf blight pathogen X. oryzae pv. oryzae. Production of Indole-3-Acetic Acid (IAA) and genomic regions encoding anti-microbial peptides emphasize its potential contributions to plant hosts. This study underscores the importance of employing a combination of phenotypic and genotypic methods in culturomics to enhance our understanding of rice seed microbiome diversity.

Pinwheel-like Curved Aromatics from the Cyclotrimerization of Strained Alkyne Cycloparaphenylenes.

Carbon nanomaterials composed of curved aromatics, such as carbon nanotubes, are difficult to selectively synthesize and modify precisely. Smaller molecular fragments of curved nanomaterials, such as cycloparaphenylenes, benefit from the precision of bottom-up synthesis, however, efforts to expand the curved molecular framework into even larger structures often rely on restrictive early stage synthetic strategies or difficult to control polymerizations. In this work we report a high yielding, strain-promoted, late-stage modification of a series of [n + 1]CPPs. We show that the conversion of these [n + 1]CPPs into soluble, pinwheel-like multipore carbon nanostructures is achievable via a straightforward and efficient metal-mediated alkyne cyclotrimerization reaction. We provide insight into suitable metals for this transformation, the photophysics of these trimeric molecules, as well as their strain profiles and crystal packing. We also demonstrate the strain-enhanced nature of the reaction under the optimized conditions, showing that strained internal-alkyne [n + 1]CPPs efficiently undergo complete conversion whereas unstrained diphenylacetylene remains completely unreacted. We anticipate that this work will have broader impacts on the study of reactivity in strained-alkyne-containing hydrocarbons, and that access to this new molecular architecture will inspire new research and applications in materials science and related fields.

Plastic Polymers and Antibiotic Resistance in an Antarctic Environment (Ross Sea): Are We Revealing the Tip of an Iceberg?

Microbial colonization of plastic polymers in Antarctic environments is an under-investigated issue. While several studies are documenting the spread of plastic pollution in the Ross Sea, whether the formation of a plastisphere (namely the complex microbial assemblage colonizing plastics) may favor the spread of antibiotic-resistant bacteria (ARB) in this marine environment is unknown yet. A colonization experiment was performed in this ecosystem, aiming at exploring the potential role of plastic polymers as a reservoir of antibiotic resistance. To this end, the biofilm-producing activity and the antibiotic susceptibility profiles of bacterial strains isolated from biofilms colonizing submerged polyvinylchloride and polyethylene panels were screened. The colonization experiment was carried out at two different sites of the Ross Sea, namely Road Bay and Tethys Bay. Most of bacterial isolates were able to produce biofilm; several multidrug resistances were detected in the bacterial members of biofilms associated to PVC and PE (also named as the plastisphere), as well as in the bacterial strains isolated from the surrounding water. The lowest percentage of ARB was found in the PE-associated plastisphere from the not-impacted (control) Punta Stocchino station, whereas the highest one was detected in the PVC-associated plastisphere from the Tethys Bay station. However, no selective enrichment of ARB in relation to the study sites or to either type of plastic material was observed, suggesting that resistance to antibiotics was a generalized widespread phenomenon. Resistance against to all the three classes of antibiotics assayed in this study (i.e., cell wall antibiotics, nucleic acids, and protein synthesis inhibitors) was observed. The high percentage of bacterial isolates showing resistance in remote environments like Antarctic ones, suffering increasing anthropic pressure, points out an emerging threat with a potential pathogenic risk that needs further deepening studies.

Alterations in the Antimicrobial Resistance Profile of Acinetobacter baumannii Strains Isolated from Intensive Care Unit Patients: Five-Year Follow-up in Cappadocia

Background: This study aims to determine alterations in the antibiotic resistance status of Acinetobacter baumannii strains isolated from lower respiratory tract samples of patients in intensive care units over the years. Methods: In this comprehensive study, A. baumannii strains isolated from aspirate and sputum samples of patients hospitalized in intensive care units of a second-stage state hospital between January 2018 and December 2022 were meticulously and retrospectively investigated and analyzed for antimicrobial resistance. Results: The rate of aspirate and sputum samples in the study was 18.1% (754/4151); The positivity rate of cultures was 51.7% (390/754); The rate of those associated with A. baumannii was found to be 65.6% (256/390).. 90.2% of the isolates were isolated from the general intensive care unit (231/256). The rates of A. baumannii isolated from aspirate and sputum samples were 67.4% (213/316) and 58.1% (43/74), respectively. The carbapenem resistance rate in A. baumannii isolates grown in aspirate samples was 96.5%, fluoroquinolone resistance was 91.7%; The carbapenem resistance rate in sputum samples was 96.1% and fluoroquinolone resistance was 90.9%. The most effective antibiotics against A. baumannii strains isolated from both aspirate and sputum samples were colistin 100% (n=256), TMP/SXT 55.8% (143/256), tigecycline 50.3% (129/256), respectively. Conclusion: Our study reveals a concerning trend-a high frequency of multidrug-resistant A. baumannii isolates are being identified in the Central Anatolia region of our country. This high prevalence, which is a cause for immediate concern, underscores the urgent and immediate need for robust infection control measures to curb the spread of A. baumannii in hospitals.

Probing the Nature of Single-Photon Emitters in a WSe2 Monolayer by Magneto-Photoluminescence Spectroscopy.

Monolayer transition metal dichalcogenides (TMDs) have emerged as promising materials to generate single-photon emitters (SPEs). While there are several previous reports in the literature about TMD-based SPEs, the precise nature of the excitonic states involved in them is still under debate. Here, we use magneto-optical techniques under in-plane and out-of-plane magnetic fields to investigate the nature of SPEs in WSe2 monolayers on glass substrates under different strain profiles. Our results reveal important changes on the exciton localization and, consequently, on the optical properties of SPEs. Remarkably, we observe an anomalous PL energy redshift with no significant changes of photoluminescence (PL) intensity under an in-plane magnetic field. We present a model to explain this redshift based on intervalley defect excitons under a parallel magnetic field. Overall, our results offer important insights into the nature of SPEs in TMDs, which are valuable for future applications in quantum technologies.

Epidemiology of Infections Caused by ESBL-Producing Enterobacteriaceae and Antibiotic Resistance Profile of Strains Isolated at Meknes-Based Moulay Ismail Military Hospital: A Retrospective Study from January 2018 to December 2020

Introduction: Infections caused by ESBL-producing Enterobacteriaceae (ESBL-PE) pose a major public health challenge. In addition to their widespread presence and growing resistance to several categories of antibiotics, the medical management of these bacteria becomes intricate, potentially resulting in a therapeutic impasse. Our study's goal is to examine the regional epidemiological characteristics of ESBL-PE infections and present a current assessment of their antibiotic resistance. Methods: The retrospective investigation undertaken at the bacteriology laboratory of the Meknes-based Moulay Ismail Military Hospital, covering a period of three years (January 2018 to March 2021), specifically examines the isolates of ESBL-PE. Results: Among the 2596 strains of Enterobacteriaceae described, 16.4% were found to produce ESBL, with E. coli being accountable for 63.6% of these strains. 85.1% of these ESBL-PE were isolated from urine samples. Surgical services were the largest source of these ESBL-PE (54.3%), followed by the emergency department (22%), medical services (14.5%), and intensive care unit (9.2%). The antibiotic resistance of these ESBL-PE has been studied and found to be high for gentamicin (63%), tobramycin (66%), cotrimoxazole (85%), and ciprofloxacin (91%). Only 7% exhibited good sensitivity to amikacin, 4% to imipenem, and 5% to fosfomycin. Conclusion: The advent of ESBL-PE in our institution is a big challenge. To limit the use of carbapenems and prevent the spread of strains causing carbapenemases, other kinds of antibiotics can be utilized. The partnership between clinicians and the bacteriology laboratory is vital for efficiently preventing and monitoring the spread of these multidrug-resistant bacteria.

Blast-Induced Progressive Collapse Analysis: Accounting for Initial Conditions and Damage

The paper presents the progressive collapse analysis of structures, focusing on the impact of the initial conditions (particularly initial velocity) and the damage. It proposes a method that calculates the residual axial load capacity and damage of columns based on their strain profile and considers the effects of multiple blast locations. The methodology involves the conventional design of a three-story moment-resisting frame, selecting blast parameters, calculating blast pressures, and performing structural and progressive collapse analyses. The findings reveal that the Alternate Load Path Method (APM) overestimates the capacity compared to a benchmark blast–structure interaction analysis, especially when unsuitable initial conditions and damage properties are used. To address this limitation, the paper concludes the recommendations for incorporating appropriate initial conditions and damage considerations for a relatively accurate progressive collapse analysis.

Characterizing Leishmania infantum-induced resistance to trivalent stibogluconate (SbIII) through deep proteomics

Leishmania infantum belongs to the L. donovani complex, which includes species associated with visceral leishmaniasis. Traditionally, antimonial compounds have served as the primary antiparasitic treatment for all clinical forms of leishmaniasis. However, the global spread of resistance to these compounds has posed a significant challenge in the treatment in some regions. In this study, we aimed to investigate resistance to trivalent sodium stibogluconate in vitro using promastigotes from a wild strain of L. infantum. We compared the growth rates and proteomic profiles of wild-type and resistant line conducting label-free quantitative mass spectrometry-based proteomic analyses. Statistical and bioinformatics analyses were employed to evaluate the significance of protein concentration changes, protein identity annotation, GO term analysis, biosynthetic pathways, and protein-protein interactions. Our findings revealed that the resistant line displayed a notable reduction in growth rate. Proteomic data unveiled similar protein concentrations per cell in both groups but with differing molecule copy numbers. We identified 165 proteins with increased concentration, these were associated with transcription and translation activities, lipid metabolism, energy metabolism, and peroxisome biogenesis. In the decreased protein groups were 56 proteins linked to metal acquisition and metabolism, particularly iron. These results suggest a novel perspective on antimonial resistance, highlighting the importance of post-transcriptional and post-translational regulation, alongside energy expenditure compensation and alterations in organelle membrane lipid composition in antimonial-resistant parasites. Overall, our study provides insights into the proteomic profile of stibogluconate-resistant strain, contributing to our general understanding of the complex landscape of antiparasitic resistance in L. infantum. SignificanceSpecies within the Leishmania donovani complex are implicated in cases of visceral leishmaniasis in the world. Leishmania infantum is a species that predominates in regions spanning the Mediterranean Basin, the Middle East, Central Asia, South and Central America. Antimonials were the first treatment for leishmaniasis, however in the last decades, the resistance has emerged in subregions like India, where it is not a therapeutic option. In contrast, sodium stibogluconate (SbIII) remains the first-line treatment in the Americas. Unfortunately, the emergence of resistance has outpaced the development of new therapeutic options, thereby becoming a critical point in the struggle against the disease. In this study we performed an in-depth proteomic analysis with liquid chromatography mass-mass spectrometry (LC-MS/MS) on L. infantum with Sb-induced resistance in vitro. Results showed a complex proteomic adaptation in the resistant line, involving transcriptional and translational proteins, energy compensation, and homeostasis maintenance. These insights contribute to understanding the molecular adaptation in the parasite and provide information to new investigations related to therapeutics development.

Simulating the impact of tumor mechanical forces on glymphatic networks in the brain parenchyma.

The brain glymphatic system is currently being explored in the context of many neurological disorders and diseases, including traumatic brain injury, Alzheimer's disease, and ischemic stroke. However, little is known about the impact of brain tumors on glymphatic function. Mechanical forces generated during tumor development and growth may be responsible for compromised glymphatic transport pathways, reducing waste clearance and cerebrospinal fluid (CSF) transport in the brain parenchyma. One such force is solid stress, i.e., growth-induced forces from cell hyperproliferation and excess matrix deposition. Because there are no prior studies assessing the impact of tumor-derived solid stress on glymphatic system structure and performance in the brain parenchyma, this study serves to fill an important gap in the field. We adapted a previously developed Electrical Analog Model using MATLAB Simulink for glymphatic transport coupled with Finite Element Analysis for tumor mechanical stresses and strains in COMSOL. This allowed simulation of the impact of tumor mechanical force generation on fluid transport within brain parenchymal glymphatic units-which include perivascular spaces, astrocytic networks, interstitial spaces, and capillary basement membranes. We conducted a parametric analysis to compare the contributions of tumor size, tumor proximity, and ratio of glymphatic subunits to the stress and strain experienced by the glymphatic unit and corresponding reduction in flow rate of CSF. Mechanical stresses intensify with proximity to the tumor and increasing tumor size, highlighting the vulnerability of nearby glymphatic units to tumor-derived forces. Our stress and strain profiles reveal compressive deformation of these surrounding glymphatics and demonstrate that varying the relative contributions of astrocytes vs. interstitial spaces impact the resulting glymphatic structure significantly under tumor mechanical forces. Increased tumor size and proximity caused increased stress and strain across all glymphatic subunits, as does decreased astrocyte composition. Indeed, our model reveals an inverse correlation between extent of astrocyte contribution to the composition of the glymphatic unit and the resulting mechanical stress. This increased mechanical strain across the glymphatic unit decreases the venous efflux rate of CSF, dependent on the degree of strain and the specific glymphatic subunit of interest. For example, a 20% mechanical strain on capillary basement membranes does not significantly decrease venous efflux (2% decrease in flow rates), while the same magnitude of strain on astrocyte networks and interstitial spaces decreases efflux flow rates by 7% and 22%, respectively. Our simulations reveal that solid stress from growing brain tumors directly reduces glymphatic fluid transport, independently from biochemical effects from cancer cells. Understanding these pathophysiological implications is crucial for developing targeted interventions aimed at restoring effective waste clearance mechanisms in the brain. This study opens potential avenues for future experimental research in brain tumor-related glymphatic dysfunction.

Hydrolysis probe assays for the detection of pathogenic Enterohemorrhagic Escherichia coli: Multi-Country validation study

Enterohemorrhagic Escherichia coli (EHEC) strains are foodborne pathogens frequently associated with outbreaks linked to red meat, posing significant global food safety concerns. While several commercial assays exist for detecting EHEC strains belonging to serogroups O26, O103, O111, and O121, they often fail to distinguish pathogenic strains from non-pathogenic strains lacking virulence genes. These non-pathogenic E. coli interfere with the accuracy of existing assays, resulting in false-positives rates between 81 – 100 % for beef products. This study aimed to standardize and validate four hydrolysis probe assays for the specific detection of pathogenic strains of E. coli O26, O103, O111, and O121. Primers and probes were designed to target single nucleotide polymorphisms conserved among pathogenic strains of each target serogroup. The standardized assays were validated using a comprehensive collection of pure culture and DNA samples (n = 248) from Canada, France, Switzerland, and the United States; laboratory-inoculated beef and spinach (n = 132), fractionally inoculated ground beef (n = 390), and samples from the federal red meat surveillance program (n = 166). The results demonstrated an overall accuracy of 94.8 % in predicting the virulence profile of pure culture strains. These four assays are a single-step PCR screening tool that can determine the presence of virulent strains. These assays provide food testing laboratories worldwide with a set of reliable methods for identifying pathogenic O26, O103, O111, and O121 strains. Thus, this assay will help to reduce product waste and financial losses caused by misleading positive results caused by presence of non-pathogenic strains.

Role of Dipicolinic Acid in Heat Resistance of Spores of Clostridium botulinum and Clostridium sporogenes PA3679 by Thermal and Pressure-assisted Thermal Processing

Dipicolinic acid (DPA) is a major constituent of spores and reportedly provides protection against inactivation by various thermal processes; however, the relationship between DPA and resistance towards pressure-assisted thermal processing is not well understood. Thermal and pressure-assisted thermal inactivation studies of Clostridium botulinum nonproteolytic strains QC-B and 610-F, proteolytic strain Giorgio-A, and thermal surrogate Clostridium sporogenes PA3679 spores suspended in ACES buffer (0.05 M, pH 7.0) were performed to determine if a relationship exists between DPA release and log reduction of spores. Thermal inactivation at 80, 83, and 87 °C for nonproteolytic strains and 101, 105, and 108 °C for the proteolytic strain and thermal surrogate were conducted. Pressure-assisted thermal inactivation for nonproteolytic strains at 83 °C/600 MPa and for the proteolytic strain and thermal surrogate at 105 °C/600 MPa were performed. Surviving spores were enumerated by 5-tube MPN method for log reductions and analyzed for released DPA by liquid chromatography-tandem mass spectrometry. The correlation between MPN log reductions, released DPA, and D-values were calculated. A positive correlation between released DPA and log reduction of spores was observed for QC-B and 610-F at 80 and 83 °C (r = 0.6073 − 0.7755; P < 0.01). At 87 °C, a positive correlation was detected for 610-F (r = 0.4242, P < 0.05) and no correlation was observed for QC-B (r = 0.1641; P > 0.05). A strong, positive correlation (r = 0.8359 − 0.9284; P < 0.05) between released DPA and log reduction of spores was observed for Giorgio-A at 101, 105, and 108 °C, and a strong, positive correlation (r = 0.8402; P < 0.05) was observed for PA3679 at 101 °C. A positive correlation (r = 0.5646 − 0.6724; P < 0.01) was observed for QC-B, 610-F, and Giorgio-A after pressure-assisted thermal treatment. No correlation (r = 02494; P > 0.05) was found for PA3679 after pressure-assisted thermal treatment. These results suggest a correlation exists between DPA release and heat resistance; however, the level of correlation varied between strains and temperatures. The findings from this research may aid in the development of spore inactivation strategies targeting the thermal resistance profiles of various strains of C. botulinum spores.