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1.
Sci Rep ; 14(1): 10531, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38719880

RESUMEN

This study aims to explore the optimal driving speed for ground vibration in suburban railway underground sections. We focused on the ground surface of suburban railway underground sections and developed a 3D finite element dynamic coupling model for the tunnel-soil system. Subsequently, considering factors such as train speed and passenger load, we analyzed the propagation characteristics of ground vibration responses in urban railway underground sections. The research results indicate a significant amplification phenomenon in the peak power spectrum of measurement points near the tunnels in underground sections. The high-frequency components of the power spectrum between measurement points are noticeably higher between the two tunnels. Furthermore, as the train speed increases, this amplification phenomenon becomes more pronounced, and the power spectrum of each measurement point mainly concentrates on several frequency bands, with the amplitude of the power spectrum near the prominent frequencies also increasing. However, when the train speed is between 100 and 120 km/h, the impact on the amplitude of the power spectrum at measurement points above the running tunnel is minimal. Additionally, the amplitude of the middle-to-high frequency components in the power spectrum increases with the increase in passenger numbers. The impact on the peak acceleration amplitude at each measurement point is minimal when the train speed is 80 km/h or below. However, once the train speed exceeds 80 km/h, the peak acceleration amplitude above the running tunnel rapidly increases, reaching its maximum value at 113 km/h, and then gradually decreasing.

2.
Nat Commun ; 15(1): 3782, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38710678

RESUMEN

Thermoelectrics have great potential for use in waste heat recovery to improve energy utilization. Moreover, serving as a solid-state heat pump, they have found practical application in cooling electronic products. Nevertheless, the scarcity of commercial Bi2Te3 raw materials has impeded the sustainable and widespread application of thermoelectric technology. In this study, we developed a low-cost and earth-abundant PbS compound with impressive thermoelectric performance. The optimized n-type PbS material achieved a record-high room temperature ZT of 0.64 in this system. Additionally, the first thermoelectric cooling device based on n-type PbS was fabricated, which exhibits a remarkable cooling temperature difference of ~36.9 K at room temperature. Meanwhile, the power generation efficiency of a single-leg device employing our n-type PbS material reaches ~8%, showing significant potential in harvesting waste heat into valuable electrical power. This study demonstrates the feasibility of sustainable n-type PbS as a viable alternative to commercial Bi2Te3, thereby extending the application of thermoelectrics.

3.
Nat Commun ; 15(1): 4519, 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38806474

RESUMEN

Protein ubiquitination regulates a wide range of cellular processes. The degree of protein ubiquitination is determined by the delicate balance between ubiquitin ligase (E3)-mediated ubiquitination and deubiquitinase (DUB)-mediated deubiquitination. In comparison to the E3-substrate interactions, the DUB-substrate interactions (DSIs) remain insufficiently investigated. To address this challenge, we introduce a protein sequence-based ab initio method, TransDSI, which transfers proteome-scale evolutionary information to predict unknown DSIs despite inadequate training datasets. An explainable module is integrated to suggest the critical protein regions for DSIs while predicting DSIs. TransDSI outperforms multiple machine learning strategies against both cross-validation and independent test. Two predicted DUBs (USP11 and USP20) for FOXP3 are validated by "wet lab" experiments, along with two predicted substrates (AR and p53) for USP22. TransDSI provides new functional perspective on proteins by identifying regulatory DSIs, and offers clues for potential tumor drug target discovery and precision drug application.


Asunto(s)
Enzimas Desubicuitinizantes , Proteoma , Ubiquitinación , Humanos , Proteoma/metabolismo , Enzimas Desubicuitinizantes/metabolismo , Enzimas Desubicuitinizantes/genética , Aprendizaje Profundo , Ubiquitina Tiolesterasa/metabolismo , Ubiquitina Tiolesterasa/genética , Ubiquitina Tiolesterasa/química , Especificidad por Sustrato , Factores de Transcripción Forkhead/metabolismo , Factores de Transcripción Forkhead/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Aprendizaje Automático , Unión Proteica , Secuencia de Aminoácidos , Tioléster Hidrolasas
4.
EMBO J ; 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38806659

RESUMEN

Microtubule-based kinesin motor proteins are crucial for intracellular transport, but their hyperactivation can be detrimental for cellular functions. This study investigated the impact of a constitutively active ciliary kinesin mutant, OSM-3CA, on sensory cilia in C. elegans. Surprisingly, we found that OSM-3CA was absent from cilia but underwent disposal through membrane abscission at the tips of aberrant neurites. Neighboring glial cells engulf and eliminate the released OSM-3CA, a process that depends on the engulfment receptor CED-1. Through genetic suppressor screens, we identified intragenic mutations in the OSM-3CA motor domain and mutations inhibiting the ciliary kinase DYF-5, both of which restored normal cilia in OSM-3CA-expressing animals. We showed that conformational changes in OSM-3CA prevent its entry into cilia, and OSM-3CA disposal requires its hyperactivity. Finally, we provide evidence that neurons also dispose of hyperactive kinesin-1 resulting from a clinic variant associated with amyotrophic lateral sclerosis, suggesting a widespread mechanism for regulating hyperactive kinesins.

5.
J Colloid Interface Sci ; 671: 154-164, 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38797141

RESUMEN

Although various conductive hydrogels have been developed for sensing, ideal materials for meeting the safety and toughness requirements of food detection are still lacking. This study introduces Ion-SSPB, a conductive hydrogel fabricated from eco-friendly, food-grade materials such as corn starch (CS), sodium alginate (SA), polyvinyl alcohol (PVA) and bentonite (BT). It leverages a green manufacturing approach designed for application in electronic food sensors. The hydrogel is achieved through a double network strategy and salt immersion method, which endows it with tunable mechanical and rheological properties. A key innovation of Ion-SSPB is the incorporation of bentonite, which enhances its performance, including low swelling, freezing resistance, and minimal residual adhesion. The hydrogel with 4% (w/v) BT concentration (Ion-SSPB4%) is an effective medium for detecting impedance changes in mangoes, correlating with their ripening stages. The Ion-SSPB hydrogel represents a significant advancement in the field of electronic food labels, combining environmental sustainability with technical efficacy.

6.
Front Surg ; 11: 1364340, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38807926

RESUMEN

Introduction: This study aims to investigate the clinical efficacy of V-Y advanced flap pedicled with freestyle perforator flap for repairing small range defects in the anterior knee region. Methods: 8 patients with skin and soft tissue defect/necrosis in the anterior knee area admitted to the Changshu No.1 People's Hospital from January 2021 to January 2022 were selected, with a defect range of 4 cm × 3 cm-9 cm × 6 cm, designed a V-Y advanced flap pedicled with freestyle perforator flap to repair the wound in the anterior knee area. Adjust the size and position of the flap according to the number and position of perforating branches found during the surgery, with a cutting area of 6 cm × 5 cm-14 cm × 10 cm and the supply area was directly pulled and sutured. Results: 4 patients were repaired by flaps pedicled with 2 perforating branches, 2 patients were repaired by flaps pedicled with 1 perforating branch and 2 patients were repaired by flaps pedicled with 3 perforating branches. 4 patients were repaired by flaps pedicled with 2 perforating branches, 2 patients were repaired by flaps pedicled with 1 perforating branch and 2 patients were repaired by flaps pedicled with 3 perforating branches. All flaps survived and following up for 6-15 months, the blood supply, appearance, and color of the flap were satisfactory, and the functions of knee joint flexion and extension were well preserved. Discussion: The V-Y advancement flap pedicled with freestyle perforator flap has the advantages of reliable blood supply, simple surgical operation, texture and thickness similar to the skin of the anterior knee area, and direct suture of the donor area. It is a perforator flap with good repair effect for small scale defects in the anterior knee area.

7.
Nano Lett ; 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38775803

RESUMEN

Orbital angular momentum (OAM) multiplexed holograms have attracted a great deal of attention recently due to their physically unbounded set of orthogonal helical modes. However, preserving the OAM property in each pixel hinders fine sampling of the target image in principle and requires a fundamental filtering aperture array in the detector plane. Here, we demonstrate the concept of metasurface-based vectorial holography with cylindrical vector beams (CVBs), whose unlimited polarization orders and unique polarization distributions can be used to boost information storage capacity. Although CVBs are composed of OAM modes, the holographic images do not preserve the OAM modes in our design, enabling fine sampling of the target image in a quasi-continuous way like traditional computer-generated holograms. Moreover, the images can be directly observed by passing them through a polarizer without the need for a fundamental mode filter array. We anticipate that our method may pave the way for high-capacity holographic devices.

8.
Angew Chem Int Ed Engl ; : e202406552, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38766881

RESUMEN

Triply interlocked [2]catenane complexes featuring two identical, mechanically interlocked units are extraordinarily rare chemical compounds, whose properties and applications remain open to detailed studies. Herein, we introduce the rational design of a new ligand precursor, L1, suitable for the synthesis of six triply interlocked [2]catenanes by coordination-driven self-assembly. The interlocked compounds can be reversibly converted into the corresponding simple triangular prism metallacage by addition of H2O or DMF solvents to their CH3OH solutions, thereby demonstrating the importance of π···π stacking and hydrogen bonding interactions in the formation of triply interlocked [2]catenanes. Moreover, extensive studies have been conducted to assess the remarkable photothermal conversion performance. Complex 6a, exhibiting outstanding photothermal conversion performance (conversion efficiency in solution : 31.82%), is used to prepare novel photoresponsive elastomer in combination with thermally activated liquid crystal elastomer. The resultant material displays robust response to near-infrared (NIR) laser and the capability of completely reforming the shape and reversible actuation, paving the way for the application of half-sandwich organometallic units in photo-responsive smart materials.

9.
J Hazard Mater ; 473: 134542, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38776809

RESUMEN

Extensively applied glufosinate (GLU) will trigger molecular alterations in nontarget tea plants (Camellia sinensis), which inadvertently disturbs metabolites and finally affects tea quality. The mechanistic response of tea plants to GLU remains unexplored. This study investigated GLU residue behavior, the impact on photosynthetic capacity, specialized metabolites, secondary pathways, and transcript levels in tea seedlings. Here, GLU mainly metabolized to MPP and accumulated more in mature leaves than in tender ones. GLU catastrophically affected photosynthesis, leading to leaf chlorosis, and decreased Fv/Fm and chlorophyll content. Physiological and biochemical, metabolomics, and transcriptomics analyses were integrated. Showing that GLU disrupted the photosynthetic electron transport chain, triggered ROS and antioxidant system, and inhibited photosynthetic carbon fixation. GLU targeted glutamine synthetase (GS) leading to the accumulation of ammonium and the inhibition of key umami L-theanine, causing a disorder in nitrogen metabolism, especially for amino acids synthesis. Interestingly, biosynthesis of primary flavonoids was sacrificed for defensive phenolic acids and lignin formulation, leading to possible losses in nutrition and tenderness in leaves. This study revealed the defense intricacies and potential quality deterioration of tea plants responding to GLU stress. Valuable insights into detoxification mechanisms for non-target crops post-GLU exposure were offered.

10.
Prenat Diagn ; 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38777622

RESUMEN

Trio exome sequencing was performed on a female fetus with an increased nuchal translucency, along with nasal bone hypoplasia, suspected cleft palate and abnormal outflow tract of the heart. A de novo heterozygous variant c.5500_5507del, p.(Tyr1834Argfs × 58) in the MED12 gene was detected. Loss-of-function variants in MED12 in females are associated with Hardikar syndrome (HS). A follow-up ultrasound at 15+5 weeks of gestation identified multiple fetal anomalies including bilateral cleft lip and palate, diaphragmatic hernia, atrioventricular septal defect, persistent truncus arteriosus, and bilateral renal pelvis dilation. Fetal autopsy confirmed the prenatal sonographic findings, and the MED12 variant was discussed by our multidisciplinary team to be the cause of fetal anomalies. Our case is the first prenatal one in which HS was diagnosed due to first trimester structural malformations. This case report presents another example of early identification of a major anomaly which allows earlier genetic diagnosis and more time for clinical management.

11.
Pediatr Neurol ; 156: 155-161, 2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38781724

RESUMEN

BACKGROUND: Acute disseminated encephalomyelitis (ADEM) is a common phenotype in children with myelin oligodendrocyte glycoprotein IgG (MOG-IgG)-associated disease. We aimed to identify novel genetic variants that distinguish children with MOG-IgG-positive ADEM (MOG-IgG+ ADEM) from children with MOG-IgG-negative ADEM (MOG-IgG- ADEM) using whole exome sequencing (WES) analysis. METHODS: We conducted a two-stage study design. First, we performed WES on five patients with MOG-IgG+ ADEM and five patients with MOG-IgG- ADEM. Following bioinformatics analysis, the candidate variant list was constructed. Second, 29 children with MOG-IgG+ ADEM and 27 children with MOG-IgG- ADEM, together with discovery cohort, were genotyped to identify the novel variants. RESULTS: WES resulted in 33,999 variants, and 5388 nonsynonymous variants were selected for downstream analysis. In total, 118 protein-affecting variants that were significantly different between the two groups were identified. Together with the five variants extracted from the literature, 49 variants were selected as the candidate variant list for genotyping in the replication cohort. Finally, we identified three variants: rs11171951 in NACα, rs231775 in CTLA4, and rs11171951 in GOLGA5, which were significantly different between MOG-IgG+ ADEM and MOG-IgG- ADEM. Only rs12440118 in NACα remained significant after Bonferroni correction for multiple testing (Padj < 0.001). CONCLUSIONS: We identified strong associations between NACα, CTLA4, and GOLGA5 variants and MOG-IgG+ ADEM in a Han Chinese population of Northern China, which may present novel genetic risk factor distinguishing patients with MOG-IgG+ ADEM from those with MOG-IgG- ADEM.

12.
Sci Total Environ ; : 173381, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38782274

RESUMEN

The chemical weathering process of carbonate rocks consumes a large quantity of CO2. This has great potential as a carbon sink, and it is one of a significant pathway for achieving carbon neutrality. However, the control mechanisms of karst carbon sink fluxes are unclear, and there is a lack of effective and accurate accounting. We took the Puding Shawan karst water­carbon cycle test site in China, which has identical initial conditions but different land use types, as the research subject. We used controlled experiments over six years to evaluate the mechanisms for the differences in hydrology, water chemistry, concentrations and fluxes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC). We found that the transition from rock to bare soil to grassland led to increases in the DIC concentration by 0.08-0.62 mmol⋅L-1. The inorganic carbon sink flux (CSF) increased by 3.01-5.26 t⋅C⋅km-2⋅a-1, an increase amplitude of 30-70 %. The flux of dissolved organic carbon (FDOC) increase by 0.28 to 0.52 t⋅C⋅km-2⋅a-1, an increase amplitude of 34-90 %. We also assessed the contribution of land use modifications to regional carbon neutrality, it indicate that positive land use modification can significantly regulate the karst carbon sink, with grassland having the greatest carbon sequestration ability. Moreover, in addition to DOC from soil organic matter degradation, DOC production by chemoautotrophic microorganisms utilizing DIC in groundwater may also be a potential source. Thus, coupled studies of the conversion of DIC to DOC processes in groundwater are an important step in assessing karst carbon sink fluxes.

13.
Sci Total Environ ; : 173400, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38782278

RESUMEN

The transportation sector is a significant contributor to greenhouse gas (GHG) emissions in China. However, real-world GHG emissions from in-use light-duty diesel trucks (LDDTs) are largely uncertain due to data paucity. In this study, we have conducted real driving emission (RDE) tests of real-world CO2, N2O, and CH4 emissions from 12 in-use LDDTs in China. Results reveal that China's CH4 emission rates from LDDTs are overestimated by 57.71 ±â€¯39.15 % if using the previous ratio method of CO2:CH4. Notably, under real-world driving conditions, such as speeds exceeding 60 km/h, maximum exhaust gas temperatures are reached, potentially impacting urea decomposition catalyst temperatures and subsequently influencing N2O production, which is highly sensitive to system temperature. Moreover, uphill roads can increase CO2 emissions by 51.93 % compared to downhill roads. Despite the tightening of vehicle emission standards, CO2 and N2O emissions from the LDDTs have not decreased linearly. However, LDDTs meeting the China VI standard exhibit the lowest average CO2, N2O and CH4 emission factors (EFs) of 335.26 ±â€¯21.72 g/km, 2.7 ±â€¯0.69 mg/km and 3.50 ±â€¯0.70 mg/km, respectively. At last, the uncertainties in the GHG EFs for the tested LDDTs through RDE tests were (-39 %, 82 %) in our study, while a significantly higher uncertainty (-85 %, 182 %) for GHG EFs of LDDTs were found in our study and other reported literature in China, largely due to the application of different non-native vehicle emission factor models and testing methods, as well as different vehicles of control emission standards. Our study highlights more urgent needs for direct RDE tests and the importance of considering real driving conditions, such as road grades, in special geographical regions when undertaking carbon accounting work in the transportation sector.

14.
Bioorg Med Chem Lett ; 108: 129802, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38777278

RESUMEN

Twenty-five acetophenone/piperazin-2-one (APPA) hybrids were designed and synthesized based on key pharmacophores found in anti-breast cancer drugs Neratinib, Palbociclib, and Olaparib. Compound 1j exhibited good in vitro antiproliferative activity (IC50 = 6.50 µM) and high selectivity (SI = 9.2 vs HER2-positive breast cancer cells SKBr3; SI = 7.3 vs normal breast cells MCF-10A) against triple negative breast cancer (TNBC) cells MDA-MB-468. In addition, 1j could selectively cause DNA damage, inducing the accumulation of γH2AX and P53 in MDA-MB-468 cells. It also reduced the phosphorylation level of P38 and the expression of HSP70, which further prevented the repair of DNA damage and caused cells S/G2-arrest leading to MDA-MB-468 cells death.

15.
Sci Adv ; 10(21): eadj8184, 2024 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-38781332

RESUMEN

Sinking particles are a critical conduit for the transport of surface microbes to the ocean's interior. Vertical connectivity of phylogenetic composition has been shown; however, the functional vertical connectivity of microbial communities has not yet been explored in detail. We investigated protein and taxa profiles of both free-living and particle-attached microbial communities from the surface to 3000 m depth using a combined metaproteomic and 16S rRNA amplicon sequencing approach. A clear compositional and functional vertical connectivity of microbial communities was observed throughout the water column with Oceanospirillales, Alteromonadales, and Rhodobacterales as key taxa. The surface-derived particle-associated microbes increased the expression of proteins involved in basic metabolism, organic matter processing, and environmental stress response in deep waters. This study highlights the functional vertical connectivity between surface and deep-sea microbial communities via sinking particles and reveals that a considerable proportion of the deep-sea microbes might originate from surface waters and have a major impact on the biogeochemical cycles in the deep sea.


Asunto(s)
Microbiota , Océanos y Mares , Filogenia , ARN Ribosómico 16S , Agua de Mar , ARN Ribosómico 16S/genética , Agua de Mar/microbiología , Bacterias/genética , Bacterias/clasificación
16.
Neurol Clin Pract ; 14(3): e200228, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38690148

RESUMEN

Objectives: Heterozygous missense variants in MYBPC1 have been recently identified in 13 patients from 6 families with congenital myopathy with tremor. All the patients had mild skeletal myopathy invariably associated with a distinctive myogenic tremor and hypotonia with gradual clinical improvement. However, no phenotypic description has been reported for the neonatal respiratory impairment that patients may suffer. Methods: We report 3 new patients from 2 independent families with congenital myopathy with tremor. Results: Tremors and respiratory distress associated with stridor should raise the diagnosis of congenital myopathy with tremors linked to MYBPC1-dominant variants in children with neonatal hypotonia. Discussion: Neonatal severe respiratory impairment requiring intensive noninvasive ventilation because of stridor is described in 2 patients. Stridor was previously reported in one other case and is part of the clinical features.

17.
Virology ; 595: 110091, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38718446

RESUMEN

Preliminary investigations have demonstrated that the cysteines located at the C-terminus of HEV ORF2 protein exhibits disulfide bonding capability during virus-like particles (VLPs) assembly. However, the effect and mechanism underlying the pairing of disulfide bonds formed by C627, C630, and C638 remains unclear. The p222 protein encompasses C-terminus and serves as a representative of HEV ORF2 to investigate the specific impacts of C627, C630, and C638. The three cysteines were subjected to site-directed mutagenesis and expressed in prokaryotes; Both the mutated proteins and p222 underwent polymerization except for p222A; Surprisingly, only p222 was observed as abundant spherical particles under transmission electron microscope (TEM); Stability and immunogenicity of the p222 exhibited higher than other mutated proteins; LC/MS/MS analysis identified four disulfide bonds in the p222. The novel findings suggest that the three cysteines contribute to structural and functional properties of ORF2 protein, highlighting the indispensability of each cysteine.


Asunto(s)
Cisteína , Virus de la Hepatitis E , Proteínas Virales , Cisteína/química , Cisteína/metabolismo , Virus de la Hepatitis E/genética , Virus de la Hepatitis E/química , Proteínas Virales/genética , Proteínas Virales/química , Proteínas Virales/metabolismo , Mutagénesis Sitio-Dirigida , Disulfuros/química , Disulfuros/metabolismo , Animales , Humanos
18.
Artículo en Inglés | MEDLINE | ID: mdl-38753528

RESUMEN

OBJECTIVES: Detection of early neoplastic lesions is crucial for improving the survival rates of patients with gastric cancer. Optical enhancement mode 2 is a new image-enhanced endoscopic technique that offers bright images and can improve the visibility of neoplastic lesions. This study aimed to compare the detection of neoplastic lesions with optical enhancement mode 2 and white-light imaging (WLI) in a high-risk population. METHODS: In this prospective multicenter randomized controlled trial, patients were randomly assigned to optical enhancement mode 2 or WLI groups. Detection of suspicious neoplastic lesions during the examinations was recorded, and pathological diagnoses served as the gold standard. RESULTS: A total of 1211 and 1219 individuals were included in the optical enhancement mode 2 and WLI groups, respectively. The detection rate of neoplastic lesions was significantly higher in the optical enhancement mode 2 group (5.1% vs. 1.9%; risk ratio, 2.656 [95% confidence interval, 1.630-4.330]; p < 0.001). The detection rate of neoplastic lesions with an atrophic gastritis background was significantly higher in the optical enhancement mode 2 group (8.6% vs. 2.6%, p < 0.001). The optical enhancement mode 2 group also had a higher detection rate among endoscopists with different experiences. CONCLUSIONS: Optical enhancement mode 2 was more effective than WLI for detecting neoplastic lesions in the stomach, and can serve as a new method for screening early gastric cancer in clinical practice. CLINICAL REGISTRY: United States National Library of Medicine (https://www. CLINICALTRIALS: gov), ID: NCT040720521.

19.
Food Res Int ; 183: 114225, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38760144

RESUMEN

The aim of this study was to isolate and identify the main milk-clotting proteases from Prinsepia utilis Royle. Protein isolates obtained using precipitation with 20 %-50 % ammonium sulfate (AS) showed higher milk-clotting activity (MCA) at 154.34 + 0.35 SU. Two milk-clotting proteases, namely P191 and P1831, with molecular weight of 49.665 kDa and 68.737 kDa, respectively, were isolated and identified using liquid chromatography-mass spectrometry (LC-MS/MS). Bioinformatic analysis showed that the two identified milk-clotting proteases were primarily involved in hydrolase activity and catabolic processes. Moreover, secondary structure analysis showed that P191 structurally consisted of 40.85 % of alpha-helices, 15.96 % of beta-strands, and 43.19 % of coiled coil motifs, whereas P1831 consisted of 70 % of alpha-helices, 7.5 % of beta-strands, and 22.5 % of coiled coil motifs. P191 and P1831 were shown to belong to the aspartic protease and metalloproteinase types, and exhibited stability within the pH range of 4-6 and good thermal stability at 30-80 °C. The addition of CaCl2 (<200 mg/L) increased the MCA of P191 and P1831, while the addition of NaCl (>3 mg/mL) inhibited their MCA. Moreover, P191 and P1831 preferably hydrolyzed kappa-casein, followed by alpha-casein, and to a lesser extent beta-casein. Additionally, cheese processed with the simultaneous use of the two proteases isolated in the present study exhibited good sensory properties, higher protein content, and denser microstructure compared with cheese processed using papaya rennet or calf rennet. These findings unveil the characteristics of two proteases isolated from P. utilis, their milk-clotting properties, and potential application in the cheese-making industry.


Asunto(s)
Queso , Manipulación de Alimentos , Péptido Hidrolasas , Queso/análisis , Manipulación de Alimentos/métodos , Animales , Péptido Hidrolasas/química , Péptido Hidrolasas/metabolismo , Espectrometría de Masas en Tándem , Concentración de Iones de Hidrógeno , Leche/química , Peso Molecular , Estabilidad de Enzimas , Cromatografía Liquida
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