Search Results (174)

This study investigates the use of cotton ropes (CRs) as a sustainable and cost-effective substitute for synthetic fiber-reinforced polymers for concrete confinement, offering significant environmental benefits such as lower CO₂ emissions and reduced energy consumption. The work evaluates the effectiveness of CR strips for confining concrete, including scenarios with recycled concrete aggregates (ReCA). Compressive strength improvements varied among specimens, with Specimen I-3F showing a 140.52% increase and Specimen II-3F achieving a 46.67% improvement. Strip configurations for Type I recycled aggregate concrete (RAC) outperformed full wraps on Type II RAC, exemplified by Specimen I-3S’s 84.51% improvement. Ultimate strain enhancements ranged from 915% to 4490.91%, driven by the significant rupture strain of cotton rope confinement. For Type I RAC, complete wrapping significantly outperformed strip configurations by 56%, 50%, and 32% in ultimate strength improvement for 1, 2, and 3 layers, respectively. The confinement ratio, varying from 0.10 to 0.70, greatly influenced the compressive behavior, with compressive strength normalized by unconfined strength increasing consistently with the confinement ratio. A minimum confinement ratio of roughly 0.40 is required to achieve an increasing second part in the compressive behavior. The initial parabolic branch was modeled using Popovics’ formulation, revealing an elastic modulus approximately 20% lower than ACI 318-19 predictions. The second branch was described using a linear approximation, and nonlinear regression analysis produced expressions for key points on the idealized compressive curve, enhancing model accuracy for CR-confined RAC. The $R^2$ values for the nonlinear regression analysis performed on experimental results were greater than 0.90. This study highlights the effectiveness of neural network expressions to predict the compressive strength of CR-confined concrete. A strength reduction (ratio of full wrap and strip wrap height CRs) factor of 0.67 was proposed and used for strip-wrapped specimens. It was seen that the neural network models also predicted the compressive strength of partially wrapped specimens with reasonable accuracy using the strength reduction factor. Full article

The widespread and inappropriate use of antibiotics, for therapeutic and prophylactic purposes, has contributed to a global crisis of rapidly increasing antimicrobial resistance of microorganisms. This resistance is often associated with elevated mutagenesis induced by the presence of antibiotics. Additionally, subinhibitory concentrations of antibiotics can trigger stress responses in bacteria, further exacerbating this problem. In the present study, we investigated the effect of low doses of ciprofloxacin on the induction of the SOS response and the subsequent development of antibiotic resistance in Proteus spp. strains. Our findings revealed an increase in mutation frequencies within the studied strains, accompanied by a significant upregulation of recA expression. These observations were consistent across experiments involving two subinhibitory concentrations of ciprofloxacin. To establish mutation frequencies and assess gene expression changes, we utilized the Rif^S-to-Rif^R forward mutagenesis assay and RT-qPCR analysis, respectively. Furthermore, employing the microdilution method, we demonstrated that these changes could promote cross-resistance to multiple classes of antibiotics in Proteus spp. clinical strains. This, combined with the recurrent nature of Proteus-associated infections, poses a substantial risk of therapeutic failure. In conclusion, exposure to low doses of ciprofloxacin can significantly impact the susceptibility of Proteus bacilli, not only reducing their sensitivity to ciprofloxacin itself but also fostering resistance to other antibiotic classes. These findings underscore the importance of cautious antibiotic use and highlight the potential consequences of subinhibitory antibiotic exposure in clinical and environmental settings. Full article

Microbial adsorption is a cost-effective and environmentally friendly remediation method for heavy metal pollution. The adsorption mechanism of cadmium (Cd) by bacteria inhabiting extreme environments is largely unexplored. This study describes the biosorption of Cd²⁺ by Sphingomonas sp. M1-B02, which was isolated from the moraine on the north slope of Mount Everest and has a good potential for biosorption. The difference in Cd²⁺ adsorption of the strain after UV irradiation stimulation indicated that the adsorption reached 68.90% in 24 h, but the adsorption after UV irradiation increased to 80.56%. The genome of strain M1-B02 contained antioxidant genes such as mutL, recA, recO, and heavy metal repair genes such as RS14805, apaG, chrA. Hydroxyl, nitro, and etceteras bonds on the bacterial surface were involved in Cd²⁺ adsorption through complexation reactions. The metabolites of the strains were significantly different after 24 h of Cd²⁺ stress, with pyocyanin, L-proline, hypoxanthine, etc., being downregulated and presumably involved in Cd²⁺ biosorption and upregulated after UV-C irradiation, which may explain the increase in Cd²⁺ adsorption capacity of the strain after UV-C irradiation, while the strain improved the metabolism of the antioxidant metabolite carnosine, indirectly increasing the adsorption capacity of the strains for Cd²⁺. Full article

Background/Objectives: Alzheimer’s disease (AD), a leading cause of dementia, lacks effective long-term treatments. Current therapies offer temporary relief or fail to halt its progression and are often inaccessible due to cost. AD involves multiple pathological processes, including amyloid beta (Aβ) deposition, insulin resistance, tau protein hyperphosphorylation, and systemic inflammation accelerated by gut microbiota dysbiosis originating from a leaky gut. Given this context, exploring alternative therapeutic interventions capable of addressing the multifaceted components of AD etiology is essential. Methods: This study suggests D-Pinitol (DPIN) as a potential treatment modifier for AD. DPIN, derived from carob pods, demonstrates insulin-sensitizing, tau hyperphosphorylation inhibition, and antioxidant properties. To test this hypothesis, we studied whether chronic oral administration of DPIN (200 mg/kg/day) could reverse the AD-like disease progression in the 5×FAD mice. Results: Results showed that treatment of 5×FAD mice with DPIN improved cognition, reduced hippocampal Aβ and hyperphosphorylated tau levels, increased insulin-degrading enzyme (IDE) expression, enhanced pro-cognitive hormone circulation (such as ghrelin and leptin), and normalized the PI3K/Akt insulin pathway. This enhancement may be mediated through the modulation of cyclin-dependent kinase 5 (CDK5). DPIN also protected the gut barrier and microbiota, reducing the pro-inflammatory impact of the leaky gut observed in 5×FAD mice. DPIN reduced bacterial lipopolysaccharide (LPS) and LPS-associated inflammation, as well as restored intestinal proteins such as Claudin-3. This effect was associated with a modulation of gut microbiota towards a more balanced bacterial composition. Conclusions: These findings underscore DPIN’s promise in mitigating cognitive decline in the early AD stages, positioning it as a potential disease modifier. Full article

This study investigated the role of the Zymomonas mobilis recA gene in conferring stress resistance when expressed in Escherichia coli. The recA gene was cloned and expressed in E. coli BL21(DE3), producing a 39 kDa polypeptide. The results of comparative analyses demonstrated that the recombinant strain significantly enhanced survival rates under various stress conditions. In oxidative stress tests, the recombinant E. coli pET-22b(+)-recA exhibited superior survival at 3 mM and 5 mM H₂O₂ concentrations. Heat stress experiments at 50 °C and 55 °C revealed increased survival for the recombinant strain. Under ethanol stress, particularly at 20% (v/v), E. coli pET-22b(+)-recA displayed higher viability than controls. UV-C exposure tests further highlighted the protective effect of recA expression, with the recombinant strain maintaining viability after 60 min of exposure, while control strains showed no survival. These results indicate that the Z. mobilis recA gene product enhances resistance to oxidative, heat, ethanol, and UV-C stresses when expressed in E. coli. This study elucidates the broad stress-protective functions of the RecA protein across bacterial species and suggests potential applications in developing stress-tolerant bacterial strains for biotechnological purposes. Full article

Thermal ice drilling technology is extensively used in drilling operations such as temperature measurement holes and subglacial water environment investigations in Antarctica owing to its advantages of compactness, light weight, and ease of operation. However, thermal drilling disturbs the initial temperature of the surrounding ice, making it impossible to obtain the true ice temperature through a borehole within a short period. Meltwater refreezing also causes the borehole to shrink and close, posing a threat to drilling safety. Therefore, obtaining an accurate characterization of the temperature field around the hole and assessing the meltwater refreezing rate are crucial for determining the appropriate temperature measurement duration and optimizing drilling parameters. To address this issue, a temperature measurement platform for the ice surrounding the borehole was developed. Experimental investigations were conducted to analyze the temperature fields during thermal drilling using both small-diameter thermal heads and RECoverable Autonomous Sonde (RECAS) thermal heads. This study clarifies the temperature field changes in the surrounding ice during and after thermal drilling. It also elucidates the effects of parameters such as the ice temperature, thermal head heating power, and thermal head diameter on the temperature field around the hole and estimates the meltwater refreezing rate inside the borehole. The results indicated that the temperature of the surrounding ice peaked approximately 5–7 h after drilling and subsequently decreased and returned to the original temperature within 48 h. The thermal disturbance radius in the surrounding ice was approximately 1.1 to 1.7 times the borehole radius when the thermal head passed through. However, after the thermal head passed, the thermal disturbance radius continued to expand owing to the heat released from meltwater refreezing, reaching 9.7 to 12.5 times the borehole radius. The average meltwater refreezing rate, estimated from temperature measurement tests at −16 °C, was 3.6 mm/h. Full article

Enzymes secreted by white rot fungi (WRF), such as laccase, offer a promising approach for the treatment of hazardous xenobiotic compounds. This study conducted a comprehensive analysis of the impact of the pesticides 2,4-dichlorophenoxyacetic acid (2,4-D) and chlorpyrifos on the laccase of Phlebia brevispora BAFC 633 through in vitro and bioinformatics analyses. The fungal strain was shown to be tolerant to both pesticides, with notable morphological and ultrastructural alterations in the mycelium. Laccase activity and two isoenzymes (53 and 70 kDa) were detected in all initial treatments. The laccase was concentrated for subsequent catalytic evaluation in the presence of both pesticides, showing high stability at a pH of 3.6 and a temperature range of 50–60 °C. The lacI gene, corresponding to this laccase, was modeled, and its structure revealed a defined catalytic pocket validated with a drug score of 0.61. Molecular docking estimated affinity energies of −5.06 and −9.41 Kcal mol⁻¹ for 2,4-D and chlorpyrifos, respectively. Molecular Mechanics Poisson–Boltzmann Surface Area (MM/PBSA) analysis through 250 ns of molecular dynamics revealed stronger hydrophobic interactions of laccase with chlorpyrifos and highlighted the importance of residue His460 in stabilizing both complexes. Understanding the impact of these agrochemicals on the catalytic function of laccase is crucial for developing future biotechnological strategies involving this enzyme. Full article

Genetic variability in bacterial populations that nodulate Lupinus cosentinii in Tunisia was investigated. Phylogenetic studies of 40 isolates using recA partial sequences categorized them into three clusters within the Bradyrhizobium genus. Twenty-three strains selected from the three clusters were thoroughly examined through housekeeping genes (recA, glnII and rpoB) multilocus sequence analysis (MLSA). Our results showed that 23 representative strains were distributed in five distinct clusters, with 13 strains belonging to Bradyrhizobium canariense BTA-1^T/Bradyrhizobium lupini USDA3051^T (10 strains) and Bradyrhizobium hipponense aSej3^T (three strains) lineages. Interestingly, eight strains occupied a separate position and could belong to two putative novel Bradyrhizobium species. The nodC phylogeny placed the 23 strains within three symbiovars: genistearum (19 strains), lupini (two strains) and, for the first time, the symbiovar cyanophyllae (two strains). Based on the worldwide phylogeography of rhizobial symbionts nodulating lupine (14 species), our results reported that eight species occurred in more than one continent, and six species were specific for one continent, e.g., Bradyrhizobium rifense, Bradyrhizobium diazoefficiens, Phyllobacterium sp. and Devosia sp. were specific to the African continent, the Bradyrhizobium iriomotense/Bradyrhizobium stylosanthis group to America, and Bradyrhizobium valentinum to the European continent. Full article

The Burkholderia cepacia complex (Bcc) is a group of bacteria with similar biological properties which are an important cause of opportunistic infections. Identification of the Bcc species is important to understand clinical outcomes in human patients. However, there are few studies of Bcc species infecting companion animals such as cats. This report shows for the first time an infection with B. pseudomultivorans, a member of Bcc, in veterinary medicine. A 9-year-old, FIV-positive, mixed-breed cat was subjected to immunosuppressive therapy, developed septic shock, and died. In the bone marrow specimen collected postmortem, numerous short bacilli—some of which were phagocytosed by leukocytes—were observed. By bacteriological examination, the Bcc-like bacteria were isolated from the bone marrow sample. Genetic analysis showed that the recA gene sequence detected from the present case exhibited the highest homology (98–100%) to that of B. pseudomultivorans. Based on these examinations, the present case was diagnosed as B. pseudomultivorans infection. The findings of this study highlight the need for investigation of the Bcc species in veterinary practice to help in treatment decisions and the prognostic evaluation of Bcc infections. Full article

Species identification of Listeria isolates remained a tedious process still based on culturing methods that, in recent years, have led to the description of many species that are not even part of the genus Listeria. It is advisable to provide new precise techniques since this taxon includes two pathogens that are usually transmitted through the food chain, Listeria monocytogenes and L. ivanovii. The approach, so-called multilocus phylogenetic analysis (MLPA) that uses several concatenated housekeeping gene sequences, provides accurate and affordable classification frameworks to easily identify Listeria species by simple Sanger sequencing. Fragments of seven housekeeping genes (gyrA, cpn60, parE, recA, rpoB, atpA, and gyrB) from 218 strains of all Listeria species currently described were used to build an MLPA of the concatenated sequence, a total of 4375 bp. All isolates subjected to identification were clustered within the species of Listeria sensu stricto, L. monocytogenes, L. innocua, and L. welshimeri, and some reference strains were reclassified as L. ivanovii and L. seeligeri. Housekeeping-gene sequencing has been demonstrated to represent a pragmatic tool that can be firmly considered in food control. Full article

Biological nitrogen fixation by rhizobia-nodulated legumes reduces the dependence on synthetic nitrogen fertilizers. Identification of locally adapted rhizobia may uncover economically valuable strains for sustainable agriculture. This study investigated the diversity and symbiotic potential of rhizobia associated with three Medicago species from Eastern Romania’s ecosystems. Phenotypic screening ensured that only rhizobial species were retained for molecular characterization. 16S rDNA sequencing clustered the isolates into four distinct groups: Sinorhizobium meliloti, Sinorhizobium medicae, Rhizobium leguminosarum, and Mesorhizobium spp. The chromosomal genes (atpD, glnII, recA) and nifH phylogenies were congruent, while the nodA phylogeny grouped the Mesorhizobium spp. isolates with R. leguminosarum. Medicago sativa was the most sampled plant species, and only S. meliloti and R. leguminosarum were found in its nodules, while Medicago falcata nodules hosted S. meliloti and Mesorhizobium spp. Medicago lupulina was the only species that hosted all four identified rhizobial groups, including S. medicae. This study provides the first report on the Mesorhizobium spp. associated with M. falcata nodules. Additionally, R. leguminosarum and two Mesorhizobium genospecies were identified as novel symbionts for Medicago spp. Comparative analysis of Medicago-associated rhizobia from other studies revealed that differences in 16S rDNA sequence type composition were influenced by Medicago species identity rather than geographic region. Full article

Approximately 90% of patients with arthritis exhibit forefoot deformities, including deformities within the metatarsophalangeal and proximal interphalangeal joints. Current pharmacological treatment with Disease Modifying Antirheumatic Drugs (DMARDs) consists of two groups: synthetic drugs (sDMARDs) and biological drugs (bDMARDs). The objective of our study was to investigate foot anthropometry changes in RA patients based on the administered treatment over a five-year period Method: A longitudinal analysis was conducted with RA patients who were grouped based on their pharmacological treatment. The pharmacological treatment groups were categorized into (I) methotrexate (MTX), (II) MTX plus biological treatments (including all variables), (III) biological treatment alone, and (IV) a miscellaneous group comprising patients with diverse treatments, including patients for whom various drugs had failed or who had not achieved remission with pharmacological treatment. For the anthropometric measurements, a foot measurement platform validated by McPoil et al. was used. Post hoc analyses with Bonferroni correction were performed to identify pairwise differences between the treatment groups while controlling for Type I errors due to multiple comparisons. Results: In the period from 2018 to 2023, significant changes were observed in several foot measurements. For instance, the MTX group showed a statistically significant increase in left heel width (p = 0.026). The MTX group experienced a slight increase in left foot length, while the Biologics and MTX + Bio groups exhibited more substantial increases in both maximum medial arch height and midfoot width. Conclusions: Different RA treatments can have a significant impact on foot structure over a five-year period, showing notable changes in heel width and overall foot morphology. Combined treatments with MTX and biologics potentially offer better management of RA. Full article

Background and Objectives: The Foot Function Index (FFI) is a widely recognized patient-reported outcome measure (PROM) for assessing foot functionality and its impact on quality of life in individuals with rheumatoid arthritis (RA). This study aimed to observe the behavior of the tool in the Spanish population with RA, optimize the tool, and check its functionality. Materials and Methods: A total of 549 RA patients, with a predominant female participation (75.6%). This study involved a comprehensive statistical analysis, leading to a refined version of the FFI for a Spanish-speaking population. Results: The original 23-item FFI was revised, resulting in a 15-item version by excluding items that caused confusion or were considered redundant. This modified version maintained the original’s subscales of pain, disability, and activity limitation, but with an adjusted item distribution. The construct validity was confirmed through exploratory factor analysis, demonstrating excellent fit indices (Kaiser–Meyer–Olkin test = 0.926, Bartlett’s test of sphericity = 4123.48, p < 0.001). The revised FFI demonstrated good internal consistency (Cronbach’s alpha = 0.96) and test–retest reliability (ICC = 0.89). Conclusions: This study highlights the applicability of the FFI in Spanish-speaking RA populations, offering a valid and reliable tool for clinicians and researchers. The modifications enhance the FFI’s relevance for RA patients, facilitating better assessment and management of foot-related functional impairments. Full article

Potatoes (Solanum tuberosum L.) represent an important food in the country’s gastronomy due to their cost, nutritional contribution, and versatility. However, many plant diseases such as the common scab—caused by Streptomyces species—reduce its yield and quality. This study aims to determine Streptomyces species being the causal agent of common scabs in a commercial potato field in the Yaqui Valley, Mexico, while identifying Bacillus strains as a biological control method to mitigate the impact of this disease under field conditions. Thus, three Streptomyces strains were selected from symptomatic samples, and then they were morphologically and molecularly (through sequencing recA and rpoB genes) identified as Streptomyces caniscabiei. After pathogenicity tests, the three strains were found to be pathogenic to potato tubers. In screening assays to identify biocontrol bacteria, strain TSO2^T (Bacillus cabrialesii subsp. tritici) and TE3^T_UV25 (Bacillus subtilis) had the best in vitro biocontrol effect against S. caniscabiei. Then, a field experiment (1 ha per treatment), under commercial conditions, was carried out to analyze the effectivity of these biocontrol bacteria to mitigate the common scabs on potato crops. After four months, the inoculation of this bacterial consortium decreased common scab incidence from 31% to 21% and increased the potato yield up to almost 5 tons/ha vs. the un-inoculated treatment. These findings demonstrate the effectiveness of the studied bacterial consortium as a potential biological control strategy to control common scabs of potato caused by Streptomyces caniscabiei, as well as increase the potato yield in the Yaqui Valley, Mexico. Full article

Phaseolus vulgaris is a globally important legume cash crop, which can carry out symbiotic nitrogen fixation with rhizobia. The presence of suitable rhizobia in cultivating soils is crucial for legume cropping, especially in areas beyond the plant-host native range, where soils may lack efficient symbiotic partners. We analyzed the distribution patterns and traits of native rhizobia associated with P. vulgaris in soils of Yunnan, where the common bean experienced a recent expansion. A total of 608 rhizobial isolates were tracked from soils of fifteen sampling sites using two local varieties of P. vulgaris. The isolates were discriminated into 43 genotypes as defined by IGS PCR-RFLP. Multiple locus sequence analysis based on recA, atpD and rpoB of representative strains placed them into 11 rhizobial species of Rhizobium involving Rhizobium sophorae, Rhizobium acidisoli, Rhizobium ecuadorense, Rhizobium hidalgonense, Rhizobium vallis, Rhizobium sophoriradicis, Rhizobium croatiense, Rhizobium anhuiense, Rhizobium phaseoli, Rhizobium chutanense and Rhizobium etli, and five unknown Rhizobium species; Rhizobium genosp. I~V. R. phaseoli and R. anhuiense were the dominant species (28.0% and 28.8%) most widely distributed, followed by R. croatiense (14.8%). The other rhizobial species were less numerous or site-specific. Phylogenies of nodC and nifH markers, were divided into two specific symbiovars, sv. phaseoli regardless of the species affiliation and sv. viciae associated with R. vallis. Through symbiotic effect assessment, all the tested strains nodulated both P. vulgaris varieties, often resulting with a significant greenness index (91–98%). However, about half of them exhibited better plant biomass performance, at least on one common bean variety, and two isolates (CYAH-6 and BLYH-15) showed a better symbiotic efficiency score. Representative strains revealed diverse abiotic stress tolerance to NaCl, acidity, alkalinity, temperature, drought and glyphosate. One strain efficient on both varieties and exhibiting stress abiotic tolerance (BLYH-15) belonged to R. genosp. IV sv. phaseoli, a species first found as a legume symbiont. Full article