Search Results (14,551)

We isolated a stress-tolerance-related gene from a genome library of Synechococcus sp. NKBG15041c. The expression of the gene in E. coli confers resistance against various stresses. The gene encodes a MoxR AAA+ ATPase, which was designated SyMRP since it belongs to the MRP subfamily. The recombinant SyMRP showed weak ATPase activity and protected citrate synthase from thermal aggregation. Interestingly, the chaperone activity of SyMRP is ATP-dependent. SyMRP exists as a stable hexamer, and ATP-dependent conformation changes were not detected via analytical ultracentrifugation (AUC) or small-angle X-ray scattering (SAXS). Although the hexameric structure predicted by AlphaFold 3 was the canonical flat-ring structure, the structures observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM) were not the canonical ring structure. In addition, the experimental SAXS profiles did not show a peak that should exist in the symmetric-ring structure. Therefore, SyMRP seems to form a hexameric structure different from the canonical hexameric structure of AAA+ ATPase. Full article

The prevalence of mental health problems in adolescence is high, and it would appear that certain conditioning factors such as having a Specific Learning Disability (SpLD), the application of educational measures (repeating a school year), or gender can have an impact on the socioemotional development of adolescents. However, we do not yet have a clear picture of the role played by each variable or whether there are interactions between them. Therefore, the objective of this study is to analyse the effect of these independent variables on internalising problems (anxiety and depression) and on personal resources (self-esteem, social competence, and awareness of the problem). The sample is composed of 80 students, 40 with SpLD and 40 control, aged between 12 and 17 years old, matched in terms of age and gender. The results indicate that the variables Specific Learning Disabilities and educational measures have a negative impact on internalising problems and personal resources of adolescents, while there is no significant effect with respect to gender. In addition, we identified interactions between having SpLD and being held back a year. We therefore call into question the negative impact of repeating a school year according to the condition. Full article

This study evaluated nematodes as an alternative to live Artemia when provided in a co-feeding regime to Pacific white shrimp (Penaeus vannamei) post-larvae (PL) reared in a biofloc nursery system. A 20-day experiment employing PL₁₁ was performed for an evaluation of four dietary groups: control [C] (fed exclusively with a dry commercial feed); artificial Artemia [AA] (dry feed composed of extracted and processed Artemia cysts and dry commercial feed); live Artemia and dry commercial feed [LA]; and nematodes and dry commercial feed [N] (Panagrolaimus sp. dry nematodes). The diets were provided twice a day, with the remaining six feed provisions being a commercial dry feed for all experimental groups. A biofloc system was chosen as it offers a potentially sustainable approach to intensive shrimp farming. Alkalinity and pH in the [N] group were significantly higher in the last 5 days of the experiment (p < 0.05), likely causing the significantly lower nitrite levels observed in that same group (p < 0.05). Total and volatile suspended solids were significantly lower in the two live feed groups when compared with [C] and [AA] (p < 0.05). Although PL fed the dry diets exhibited higher growth rates (p < 0.05), the [N] and [LA] groups presented significantly higher final survivals (p < 0.05). No differences were found for survival after a salinity stress test (p ≥ 0.05). These results suggest that nematodes can successfully substitute Artemia in a co-feeding regime for P. vannamei PL reared in biofloc nursery systems. Full article

We analyze the predictability of daily data on the CBOE $VIX$ and $SKEW$ indices, used to capture the average level of risk-neutral risk and downside risk, respectively, as implied by S&P 500 index options. In particular, we use forecast models from the Heterogeneous Autoregressive ($HAR$) class to test whether and how lagged values of the $VIX$ and of the $SKEW$ may increase the forecasting power of $HAR$ for the $SKEW$ and the $VIX$. We find that a simple $HAR$ is very hard to beat in out-of-sample experiments aimed at forecasting the $VIX$. In the case of the $SKEW$, the benchmarks (the random walk and an $AR\left(1\right)$) are clearly outperformed by $HAR$ models at all the forecast horizons considered and there is evidence that special definitions of the $SKEW$ index based on put options data only yield superior forecasts at all horizons. Full article

Background: Suicidal behaviour, defined as acting with the intention of killing oneself and thinking about doing so, is a serious public health problem. Being able to list the risk factors in the process from suicidal ideation to suicidal behaviour is important in preventing suicide. Objectives: The study was conducted to examine the psychological variables that discriminate between individuals who attempt suicide and those who only have suicidal ideation. Methods: The sample of the study consisted of 108 individuals who attempted suicide and 197 individuals with suicidal ideation, aged 18–25 years. Data were collected using the Demographic Information Form, Anger/Impulsivity (A/I) and Hopelessness/Loneliness (H/L) subscales of the Suicide Probability Scale (SPS), Psychological Pain Scale (PPS), State and Trait Anxiety Scale (STAS), Beck Depression Inventory (BDI), Interpersonal Needs Questionnaire (INQ), Acquired Suicide Efficacy/Death Fearlessness Scale (ASE/DFS) and General Attitudes and Beliefs Scale Short Form (GABS-SF). Results: Results showed that anger/impulsivity (Wald = 4.827; p < 0.05), perceived burden on others (Wald = 8.613; p < 0.05), acquired suicide efficacy/death fearlessness (Wald = 13.377; p < 0.001), being female (Wald = 3.925; p < 0.05), presence of diagnosed psychiatric illness in the family (Wald = 5.705; p < 0.05), and receiving psychological support (Wald = 4.381. p < 0.05) variables are significant predictors of the transition from suicidal ideation to suicidal action. Conclusions: The identification of psychological factors between suicide attempters and suicide ideation groups may guide clinicians in the follow-up and treatment of individuals at risk of attempting suicide. In addition, the results may contribute to the development of new intervention, education and treatment programmes for suicide. Full article

Snakebite envenoming (SBE) remains a severely neglected public health issue, particularly affecting tropical and subtropical regions, with Africa experiencing an estimated 435,000 to 580,000 snakebites annually, leading to high morbidity and mortality rates, especially across Africa and Asia. Recognized as a Neglected Tropical Disease, SBE management is further complicated by the inadequate efficacy of current antivenom treatments. Of particular concern are cobras (Naja sp.), whose neurotoxins can induce rapid fatal respiratory paralysis. In this study, we investigate the potential of nanobodies as a promising next-generation of immunotherapeutics against cobra venoms. Through a dual strategy of the characterization of venom toxic fractions from cobras captured for the first time in Algeria and Tunisia biotopes, coupled with in vitro assays to evaluate their interactions with acetylcholine receptors, and subsequent immunization of dromedaries to produce specific nanobodies, we identified two lethal fractions, F5 and F6, from each venom, and selected five nanobodies with significant binding and neutralizing of 3DL50 (0.74 mg/kg). The combination of these nanobodies demonstrated a synergistic effect, reaching 100% neutralizing efficacy of 2DL50 lethal venom fraction (0.88 mg/kg) doses in mice. Additionally, our findings highlighted the complex mechanism of cobra venom action through the lethal synergism among its major toxins. Full article

In mariculture facilities, bacterial infections pose significant production challenges, with potentially catastrophic impacts on fish species. Bacterial co-infections are a widespread phenomenon in the natural marine environment, although their impact on aquatic organisms remains poorly investigated. This study aimed to detail the pathological findings associated with a natural bacterial co-infection caused by three different pathogens, namely Photobacterium damselae subsp. piscicida, Tenacibaculum maritimum and Vibrio sp., as the cause of mass mortality in European sea bass. The fish had been reared in open-net cages in Sicily and later transferred for experimental research purposes to a user establishment after immunization with an inactivated vaccine. Macroscopic, cytological and histopathological examinations were performed on 109 animals, and bacterial species were identified by the 16S rRNA gene. Overall, ulcerative skin lesions, necrotizing myositis and tail rot with occasional tail loss were associated with tenacibaculosis and vibriosis, while P. damselae subsp. piscicida mainly caused granulomatous inflammation in the spleen and head kidney. Finally, an injection site reaction due to the oil-adjuvanted vaccine administered intraperitoneally was observed in the abdominal fat. Understanding the impact of bacterial pathogens is essential to manage the health and welfare of farmed fish, and the importance of a good health monitoring program cannot be overstated to avoid outbreaks and the possible emergence of new pathogens due to the intensification of the production systems, antibiotic resistance and climate changes. The study would also highlight the importance of the quarantine period when animals supplied for research come from aquaculture farms and how the main goal in the near future should be to better define the procedures to provide completely pathogen-free animals. Full article

The Mississippi River Delta Front (MRDF) is a subaqueous apron of rapidly deposited and weakly consolidated sediment extending from the subaerial portions of the Birdsfoot Delta of the Mississippi River, long characterized by mass-wasting sediment transport. Four (4) depositional environments dominate regionally (an undisturbed topset apron, mudflow gully, mudflow lobe, and prodelta), centering around mudflow distribution initiated by a variety of factors (hurricanes, storms, and fluid pressure). To better understand the spatiotemporal scales of the events as well as the controlling processes, eight cores (5.8–8.0 m long) taken offshore from the South Pass (SP) and the Southwest Pass (SWP) were analyzed for gamma density, grain size, sediment fabric (X-radiography), and geochronology (²¹⁰Pb/¹³⁷Cs radionuclides). Previous work has focused on the deposition of individual passes and has been restricted to <3 m core penetration, limiting its geochronologic completeness. Building on other recent studies, within the mudflow gully and lobe cores, the homogeneous stepped profiles of ²¹⁰Pb activities and the corresponding decreased gamma density indicate the presence of gravity-driven mass failures. ²¹⁰Pb/¹³⁷Cs indicates that gully sedimentary sediment accumulation since 1953 is greater than 580 cm (sediment accumulation rate [SAR] of 12.8 cm/y) in the southwest pass site, and a lower SAR of the South Pass gully sites (2.6 cm/y). This study shows that (1) recent dated mudflow deposits are identifiable in both the SWP and SP; (2) SWP mudflows have return periods of 10.7 y, six times more frequent than at the SP (66.7 y); (3) ²¹⁰Pb inventories display higher levels in the SWP area, with the highest focusing factors in proximal/gully sedimentation, and (4) submarine landslides in both study areas remain important for sediment transport despite the differences in sediment delivery and discharge source proximity. Full article

During the COVID-19 pandemic, the surge in disinfectant use emphasised their pivotal role in infection control. While the majority of antimicrobial resistance research focuses on antibiotics, resistance to biocides, which are present in disinfectants and sanitisers, is escalating. Serratia sp. HRI is a highly resistant isolate, and through the study of this organism, the molecular mechanisms of resistance may be uncovered. Serratia sp. HRI was treated with the disinfectant benzalkonium chloride in preparation for RNA sequencing. Through mining of the RNA-Seq differential expression data, an uncharacterised Major Facilitator Superfamily (MFS) efflux pump gene was found to be up-regulated at least four-fold at four different time points of exposure. Real-time PCR revealed this uncharacterised MFS efflux gene was up-regulated after exposure to benzalkonium chloride and two additional disinfectants, didecyldimethylammonium chloride (DDAC) and Virukill^TM. Additionally, expression of this gene was found to be higher at 20 min versus 90 min of exposure, indicating that the up-regulation of this gene is an initial response to biocide treatment that decreases over time. This suggests that MFS efflux pumps may be an initial survival mechanism for microorganisms, allowing time for longer-term resistance mechanisms. This work puts forward a novel biocide resistance gene that could have a major impact on biocide susceptibility and resistance. Full article

Objectives: This systematic review aimed to analyse the published evidence for the use of non-invasive methods for the early detection of oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs). Methods: The literature was systematically searched through several databases: PubMed, Cochrane Library, and Web of Science. Additional exploration was performed through cross-checks on the bibliographies of selected reviews. The inclusion criteria involved studies assessing the application of non-invasive tests on humans in the screening, diagnosis, or surveillance of OSCC or OPMDs and reporting sensitivity (SE) and specificity (SP). The Newcastle–Ottawa scale (NOS) was applied to assess the quality of the studies included. Results: The search strategy resulted in 8012 preliminary records. After a duplicate check, 116 titles remained. After abstract analysis, 70 papers remained. After full text analysis, only 54 of the 70 papers fit the inclusion criteria (28 were original articles and 26 were reviews). Those 26 reviews were used to manually search for further original articles. From this last search, 33 original articles were found. Thus, a total of 61 original studies were included and investigated. Findings from this systematic review indicate useful information, such as a description of the mechanisms, ease of use, limitations, and SE and SP values, to drive the choice of the optimal minimally invasive method to be utilized as an adjunctive tool to examine the suspicious lesions. Conclusions: Each of the analysed tools can be improved or implemented, considering their high SE and low SP. Despite advancements, incisional biopsy continues to be the gold standard for the definitive diagnosis of oral cancer and precancerous lesions. Further research and development are essential to improving the sensitivity, specificity, and reliability of non-invasive tools for widespread clinical application. Full article

High-temperature conditions are harmful for carbon nanotube-based (CNT-based) composites, as CNTs are susceptible to oxidation. On the other hand, adding CNTs to ceramics with low electrical conductivity, such as 3YSZ, is beneficial because it allows the production of complex-shaped samples with spark plasma sintering (SPS). A shielding coating system may be applied to prevent CNT oxidation. In this work, the 8YSZ (yttria-stabilized zirconia) thermal shielding coating system was deposited by aerosol deposition (AD) to improve the composite’s resistance to CNT degradation without the use of bond-coat sublayers. Additionally, the influence of the annealing process on the mechanical properties and microstructure of the composite was evaluated by nanoindentation, scratch tests, scanning electron microscopy (SEM), X-ray diffraction (XRD), flame tests, and light microscopy (LM). Annealing at 1200 °C was the optimal temperature for heat treatment, improving the coating’s mechanical strength (the first critical load increased from 0.84 N to 3.69 N) and promoting diffusion bonding between the compacted powder particles and the substrate. The deposited coating of 8YSZ increased the composite’s thermal resistance by reducing the substrate’s heating rate and preventing the oxidation of CNTs. Full article

Volatile organic compounds (VOCs) produced by Bacillus species exhibit biocontrol activity against fungal pathogens of fruits and vegetables. However, research on the effect of VOCs on Aspergillus flavus in stored grains is limited. This study aimed to investigate the effects of VOCs extracted from the strain R2, which was isolated from unhulled rice and identified as Bacillus paramycoides on A. flavus in vitro and unhulled rice. R2 VOCs effectively inhibited conidial germination and the hyphal growth of A. flavus in vitro. Moreover, R2 VOCs reduced the fungal population, aflatoxin B₁ (AFB₁) levels, and free fatty acid (FFA) value by 90.8%, 67%, and 38.7%, respectively, in unhulled rice. Eighteen R2 VOCs were identified using headspace solid-phase micro-extraction gas chromatography–mass spectrometry, and the individual activity of the VOCs against A. flavus was tested in vitro. Benzaldehyde (Ben) and 3,7-dimethyl-1-octanol (Dmo) showed strong inhibitory activities against A. flavus on PDA plates, with inhibition rates of 100% and 91.2%, respectively, at a concentration of 20 μL/dish. Ben at the concentration of 0.09 mg/mL, Dmo at the concentration of 0.07 mg/mL, or a mixture of both at halved concentrations could reduce the fungal population, AFB₁ levels, and FFA content in unhulled rice. Our findings suggest that R2 VOCs are good alternatives to traditional chemical fumigants for suppressing A. flavus in stored grains. However, further research is necessary to establish the optimal fumigation concentration of these two components in unhulled rice. The impact of their residues on grain quality should be explored through sensory evaluation and nutritional analysis, and their safety to the environment and human body should be evaluated through safety assessment. Full article

The development of serum-free media (SFM) is critical to advance cell culture techniques used in viral vaccine production and address the ethical concerns and contamination risks associated with fetal bovine serum (FBS). This study evaluated the effects of marine microalgal extracts and growth factor cocktails on the activity of Madin-Darby canine kidney (MDCK) and Vero cells. Five marine microalgal species were used: Spirulina platensis (SP), Dunaliella salina (DS), Haematococcus pluvialis (HP), Nannochloropsis salina (NS), and Tetraselmis sp. (TS). DS and SP extracts significantly increased the proliferation rate of both MDCK and Vero cells. DS had a proliferation rate of 149.56% and 195.50% in MDCK and Vero cells, respectively, compared with that in serum-free medium (SFM). Notably, DS and SP extracts significantly increased superoxide dismutase (SOD) activity, which was 118.61% in MDCK cells and 130.08% in Vero cells for DS, and 108.72% in MDCK cells and 125.63% in Vero cells for SP, indicating a reduction in intracellular oxidative stress. Marine microalgal extracts, especially DS and SP, are feasible alternatives to FBS in cell culture as they promote cell proliferation, ensure safety, and supply essential nutrients while reducing oxidative stress. Full article

The accumulation of microplastics (MPs) in the environment has been a bottleneck for scientific society. Several approaches have been described as possibilities for reducing MPs in aquatic and terrestrial ecosystems; however, most of them are not environmentally friendly. Filamentous fungi (Ff) cells are currently considered a promising solution as a treatment for MPs. Therefore, the present study reports the potential ability of Ff isolated from mangrove sediments to biodegrade low-density polyethylene MPs (LDPE_MPs). Six Ff strains were grown in batch cultures for 28 days, and one of them, Aspergillus sp. (AQ3A), showed the most prominent profile to biodegrade polymeric compounds. After morphological and molecular analysis, all strains were identified as belonging to the genera Aspergillus (MQ1C, AQ2A and AQ3A), Penicillium (MQ1A), and Trichoderma (MQ1B and MQ2A). The strain Aspergillus sp. (AQ3A) showed the most promising results with a LDPE_MPs reduction rate of 47% and biomass formation of 0.0890 g·mL⁻¹. Complementary studies with Aspergillus sp. (AQ3A) using Fourier-transform infrared spectroscopy (FTIR) highlighted changes in the molecular structure of LDPE_MPs. These results indicate that Ff can contribute to the biodegradation of LDPE_MPs. However, other parameters, mainly associated with the enzymes that are involved in this biodegradation process, need to be explored. Full article

Cucumber wilt, caused by Fusarium oxysporum f. sp. cucumerinum (FOC), is a soilborne disease that poses a significant threat to cucumber production, resulting in substantial yield losses. This study aimed to evaluate the biocontrol and growth-promoting effects of Bacillus velezensis, a highly active bacterial strain. In vitro assays revealed that B. velezensis F9 exhibited broad-spectrum antifungal activity against eight plant pathogenic fungi, with inhibition ratio ranging from 62.66% to 88.18%. Additionally, the strain displayed the ability to produce IAA (5.97 ± 1.75 µg/mL), fix nitrogen, produce siderophores, and form biofilms. In vitro growth promotion assays demonstrated that different concentrations of B. velezensis F9 significantly promoted cucumber seedling growth. Furthermore, two pot experiments revealed that the strain exhibited biocontrol efficacy against cucumber wilt, with disease control rates ranging from 42.86% to 67.78%. Notably, the strain significantly increased the plant height, fresh weight, and dry weight, with increases ranging from 20.67% to 60.04%, 40.27% to 75.51%, and 22.07% to 52.54%, respectively. Two field trials confirmed the efficacy of B. velezensis F9 in controlling cucumber wilt, with disease control rates of 44.95% and 33.99%, respectively. The strain effectively alleviated the dwarfing and wilting symptoms caused by the pathogen. Compared with the FOC treatment, the F9 + FOC treatment significantly increased the plant height, fresh weight, and dry weight, with increases of 43.85% and 56.28%, 49.49% and 23.70%, and 36.25% and 73.63%, respectively. Enzyme activity assays indicated that inoculation significantly increased SOD activity in cucumber leaves and neutral phosphatase, sucrase, and urease activity in rhizosphere soil. Correlation analysis revealed a negative correlation between the disease index and plant height, fresh weight, dry weight, and peroxidase activity, with correlation coefficients of −0.53, −0.60, −0.38, and −0.45, respectively. These findings suggest that plant height, fresh weight, and dry weight are significantly negatively correlated with the cucumber disease index, highlighting their importance as indicators for evaluating the biocontrol efficacy of B. velezensis F9. In conclusion, B. velezensis F9 is a highly effective plant growth-promoting rhizobacterium with excellent biocontrol potential, showcasing promising applications in agricultural production. Full article