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The duplex treatments of metal surfaces combining laser‐assisted functionalization and chemical modification attract a growing interest in view of better control of functional properties such as wettability. Patterned titanium oxides layers of different nature and roughness are produced in ambient atmosphere on a titanium surface using a nanosecond 532 nm Nd:YAG laser. Standalone lines and hatched surfaces obtained with different laser parameters are characterized by scanning electronic microscopy coupled with EDS analysis, micro‐Raman, XRD and X‐ray photoelectron spectroscopy (XPS). A set of surfaces having featureless and saw‐tooth morphologies of different roughnesses is modified with octylphosphonic acid (OPA). The effect of surface roughness on the efficiency of OPA grafting is investigated using XPS. It is found that the organic load on the chemically modified surfaces increases with surface roughness. The apparent thickness of the OPA layers is estimated using a standard uniform overlap model and considering the correction due to the corrugated appearance of the laser‐treated surfaces. The wetting properties of the surfaces before and after chemical modification are compared. The laser‐treated surfaces show superhydrophilic behavior consistent with Wenzel model. On the other hand, the chemically modified surfaces demonstrate a strong increase in hydrophobicity along with the roughness increase, in agreement with the Cassie–Baxter model. [ABSTRACT FROM AUTHOR]

Syrphid larvae are effective biological control agents in numerous crops due to their voracity, and they are used in both augmentative and conservation‐based strategies within horticultural systems. This study conducted laboratory trials to ascertain the predation rate of Allograpta exotica (Wiedemann) (Diptera: Syrphidae) on Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) and to compare it with the predation rate on Aphis gossypii Glover (Hemiptera: Aphididae), another significant aphid species affecting strawberries. Additionally, field trials were conducted to assess the reduction in the field population of C. fragaefolii achieved by A. exotica within strawberry crops. We observed a significant increase in the number of aphids consumed by a larva as it progressed from first‐instar larvae (L1) to third‐instar larvae (L3). Specifically, the mean aphid consumption by second‐instar larvae (L2) was nearly 11 times higher for C. fragaefolii and 10 times higher for A. gossypii compared to L1. Furthermore, the consumption rate of L3 larvae was approximately 2 times higher for both aphid species compared to L2. In laboratory conditions, A. exotica larvae significantly reduced the number of both aphid species, but the control on A. gossypii was higher than on C. fragaefolii. The results of the field experiment demonstrated that the predatory hoverfly A. exotica significantly reduced the numbers of C. fragaefolii compared to the control treatment, highlighting its potential as a promising biological control agent in strawberry crops. [ABSTRACT FROM AUTHOR]

INTRODUCTION: This study explored the ability of plasma amyloid beta (Aβ)42/Aβ40 to identify brain amyloid deposition in cognitively unimpaired (CU) individuals. METHODS: Plasma Aβ was quantified with an antibody‐free high‐performance liquid chromatography tandem mass spectrometry method from Araclon Biotech (ABtest‐MS) in a subset of 731 CU individuals from the screening visit of the Anti‐Amyloid Treatment in Asymptomatic Alzheimer's (A4) Study, to assess associations of Aβ42/Aβ40 with Aβ positron emission tomography (PET). RESULTS: A model including Aβ42/Aβ40, age, apolipoprotein E ε4, and recruitment site identified Aβ PET status with an area under the curve of 0.88 and an overall accuracy of 81%. A plasma‐based pre‐screening step could save up to 42% of the total number of Aβ PET scans. DISCUSSION: ABtest‐MS accurately identified brain amyloid deposition in a population of CU individuals, supporting its implementation in AD secondary prevention trials to reduce recruitment time and costs. Although a certain degree of heterogeneity is inherent to large and multicentric trials, ABtest‐MS could be more robust to pre‐analytical bias compared to other immunoprecipitation mass spectrometry methods. HIGHLIGHTS: Plasma amyloid beta (Aβ)42/Aβ40 accurately identified brain Aβ deposition in cognitively unimpaired individuals from the Anti‐Amyloid Treatment in Asymptomatic Alzheimer's (A4) Study.The inclusion of the recruitment site in the predictive models has a non‐negligible effect.A plasma biomarker‐based model could reduce recruitment costs in Alzheimer's disease secondary prevention trials.Antibody‐free liquid chromatography mass spectrometry methods may be more robust to pre‐analytical variability than other platforms. [ABSTRACT FROM AUTHOR]

Background: Amyloid‐β (Aβ) immunotherapy is a promising strategy for treating Alzheimer's disease (AD). Previous studies suggested that Aβ40 could have an important role in AD, especially in relation to amyloid deposition in blood vessels in AD. The AB1601 (NCT03461276) is a multicenter, randomized, double‐blind, placebo‐controlled, phase 2 study in patients with amnestic mild cognitive impairment (a‐MCI) or very mild AD (vm‐AD) which investigated the safety, tolerability and immunogenicity of repeated subcutaneous injections of ABvac40, a vaccine targeting Aβ40. The 24‐month study (Part A) showed that ABvac40 was safe, well‐tolerated and highly immunogenic. Here, an additional 18‐month cross‐over study (Part B) was conducted to evaluate safety, tolerability and immunogenicity of ABvac40 in patients randomized to placebo in Part A (Delayed start group), and to assess safety and immunogenicity of a delayed booster of ABvac40 in ABvac40‐treated patients in Part A (Booster group). Method: A total of 124 patients with a‐MCI (N = 80) or vm‐AD (N = 44) were initially included in Part A. Seventy‐seven out of 101 patients who completed Part A transitioned to Part B. Safety assessments included the frequency of amyloid‐related imaging abnormalities (ARIA). Immune response was assessed by quantification of specific anti‐Aβ40 antibodies in plasma samples. Result: ABvac40 continued to show a favorable safety profile. Specifically, no ARIA‐E was reported and ARIA‐H incidence was low, equally distributed in both groups, and similar to the placebo group (Part A). Delayed start group showed a strong and specific immune response, with a time course equivalent to the ABvac40 group in Part A. A delayed booster of ABvac40 elicited a large increase in anti‐Aβ40 antibody plasma levels, exceeding the concentrations observed throughout the active dosing phase of Part A. Conclusion: The cross‐over extension of the AB1601 Phase 2 study confirmed the excellent safety and tolerability profile of ABvac40, making this vaccine a potential candidate to be combined with other disease‐modifying therapies. Results on immunogenicity supported those obtained in Part A, demonstrating that ABvac40 elicited a strong, specific, sustained and boostable immune response. This could have important implications for long‐term treatments, especially in the context of preventive approaches. Additional exploratory efficacy results of Part B are expected in Q4‐2023. [ABSTRACT FROM AUTHOR]

Background: Early detection of β‐amyloid (Aβ) accumulation, a major biomarker for Alzheimer's disease (AD), has become important. While Aβ deposition can be detected by positron emission tomography (PET), practical fluid Aβ biomarker is also being developed recently. In the present study, we aimed to determine whether APOE genotypes, age, and cognitive status increase the predictive performance of fluid Aβ levels for amyloid PET positivity. Methods: We recruited 488 participants who underwent both plasma Aβ and Aβ PET studies (Cohort 1) and 217 participants who underwent both cerebrospinal fluid (CSF) Aβ and Aβ PET studies (Cohort 2). Plasma and CSF samples were analyzed using ABtest‐MS, an antibody‐free liquid chromatography‐differential mobility spectrometry‐triple quadrupole mass spectrometry method and INNOTEST enzyme‐linked immunosorbent assay kits, respectively. To evaluate the predictive performance of plasma Aβ and CSF Aβ, respectively, logistic regression and receiver operating characteristic analyses were performed. Results: When predicting Aβ PET status, both plasma Aβ42/40 ratio and CSF Aβ42 showed high accuracy (plasma Aβ area under the curve (AUC) 0.814; CSF Aβ AUC 0.848). In the plasma Aβ models, the AUC values were higher than plasma Aβ alone model, when the models were combined with either cognitive stage (p < 0.001) or APOE genotype (p = 0.011). On the other hand, there was no difference between the CSF Aβ models, when these variables were added. Conclusions: Plasma Aβ might be a useful predictor of Aβ PET status as much as CSF Aβ, particularly when considered with clinical information. [ABSTRACT FROM AUTHOR]

Background: The ratio Aβ42/Aβ40 in cerebrospinal fluid (CSF) is considered one of the most reliable biomarkers of Alzheimer's Disease. ABtest40‐IA and ABtest42‐IA have been widely used for amyloid‐β (Aβ) quantification in plasma samples. The aim of this study was to validate these tests for the quantification of Aβ40 and Aβ42 in CSF. Method: Analytical validation of ABtest40‐IA and ABtest42‐IA was accomplished following FDA and EMA reference guidelines. Calibration curves, sensitivity, specificity, accuracy, precision, recovery and dilution linearity were evaluated. Correlations between ABtest‐IA and an independent fully automated IVD test, (Lumipulse ® G β‐amyloid 1‐40 and 1‐42, Fujirebio), were estimated using 93 CSF samples of PET‐Aβ positive (75%) and PET‐Aβ negative (25%) individuals. Differences in CSF Aβ42/Aβ40 levels between both PET‐Aβ groups were analyzed (Mann Whitney test). The ability of CSF Aβ42/Aβ40 ratio to discriminate between PET‐Aβ positive and PET‐Aβ negative subjects was evaluated by means of Receiver Operating Characteristic (ROC) curve analysis, considering PET‐Aβ the gold standard. Result: Calibration curves ranges were set at 43.9 to 500 pg/mL for ABtest40‐IA and 5 to 100 pg/mL for ABtest42‐IA. Intra‐assay, inter‐assay and inter‐lot coefficients of variation were below 5.2% and 7.4% for ABtest40‐IA and ABtest42‐IA respectively. Accuracy evaluation provided mean relative errors of 4.6% and 7.5%. Spearman correlation coefficients between ABtest‐IA and Lumipulse® were 0.96, 0.95 and 0.93 for Aβ40, Aβ42 and Aβ42/Aβ40 respectively (p values < 0.0001). As expected, Aβ42/Aβ40 ratio levels were significantly lower in the PET‐Aβ positive group (p < 0.0001). ROC analysis of CSF Aβ42/Aβ40 gave an AUC of 0.85 (95% CI 0.74 to 0.97), very similar to that obtained with Lumipulse®: 0.84 (95% CI 0.72 to 0.98). The overall agreement of PET‐Aβ and ABtest‐IA Aβ42/Aβ40 was 90%, being false positives the majority (78%) of the misclassified subjects. Results are supporting that CSF Aβ42/Aβ40 is an early biomarker of cerebral amyloid deposition. Conclusion: ABtest40‐IA and ABtest42‐IA were successfully validated as new precise and accurate tools for the quantification of Aβ40 and Aβ42 in CSF samples. ABtest‐IA measures of Aβ42/Aβ40 ratio in CSF identified individuals with brain amyloid deposition with equivalent ability to other test commercially available. [ABSTRACT FROM AUTHOR]

The purification and preliminary crystallographic analysis of the archaeal CBS-domain protein MJ1004 from Methanocaldococcus jannaschii are described. The native protein was overexpressed, purified and crystallized in the monoclinic space group P21, with unit-cell parameters a = 54.4, b = 53.8, c = 82.6 Å, β = 106.1°. The crystals diffracted X-rays to 2.7 Å resolution using synchrotron radiation. Matthews-volume calculations suggested the presence of two molecules in the asymmetric unit that are likely to correspond to a dimeric species, which is also observed in solution. [ABSTRACT FROM AUTHOR]

Summary: MbeA is a 60 kDa protein encoded by plasmid ColE1. It plays a key role in conjugative mobilization. MbeA*, a slightly truncated version of MbeA, was purified for in vitro analysis. MbeA* catalysed DNA cleavage and strand-transfer reactions using oligonucleotides embracing the ColE1 nic site, which was mapped to 5′-(1469)CTGG/CTTA(1462)-3′. Thus MbeA is the relaxase for ColE1 conjugal mobilization, in spite of the fact that it lacks a three histidine motif considered the invariant signature of conjugative relaxases. Amino acid sequence comparisons suggest MbeA is nevertheless related to the common relaxase protein family. For instance, MbeA residue Y19 could correspond to the invariant tyrosine in Motif I, whereas H97, E104 and N106 may constitute the equivalent residues to the histidine triad in Motif III. This hypothesis was tested by site-directed mutagenesis. MbeA amino acid residues Y19, H97, E104 and N106 were changed to alanine. MbeA mutant N106A showed reduced oligonucleotide cleavage and strand-transfer activities, whereas mutation in the other three residues resulted in proteins without detectable activity, suggesting they are directly implicated in catalysis of DNA-cleavage and strand-transfer reactions. A double substitution of E104 and N106 by histidines, therefore reconstituting the canonical histidine triad, restored relaxase activities to 1% of wild type. Thus, MbeA is a variant of the common relaxase theme with a HEN signature motif, which has to be added to the canonical three histidine motif of previously reported relaxases.. [ABSTRACT FROM AUTHOR]

Background: We have completed the analytical validation of an antibody‐free, HPLC‐MS/MS method (ABtest‐MS), to quantitate specifically Aβ1‐40 and Aβ1‐42 in plasma with high precision (inter‐assay %CV 6.2‐7.0% for Aβ1‐40 and 6.1%‐11.0% for Aβ1‐42) and accuracy (%RE ‐0.6 to 0.3% for Aβ1‐40 and ‐1.5 to 1.3% for Aβ1‐42). Previous studies have shown that the Aβ42/Aβ40 ratio in plasma predicts β‐amyloid status reliably, suggesting that the assessment of plasma Aβ levels could be a useful screening tool for Alzheimer's Disease (AD) clinical trials, reducing the need for invasive or complex procedures. In this work we explore the ability of Aβ42/Aβ40 plasma ratio to predict the Aβ‐PET status at baseline visit in the ABvac40 (an active vaccine against Aβ40) phase II clinical trial. Method: Aβ40 and Aβ42 plasma levels from 73 amnestic‐MCI (a‐MCI) participants, who had previously given their consent, were quantitated with ABtest‐MS. Levels of p‐tau181 were assessed with Simoa® p‐tau181 V2 Advantage Kit (Quanterix). The ability of plasma Aβ42/Aβ40 ratio or p‐tau181 to detect Aβ‐PET positivity was assessed as the area under the ROC curve (AUC). Result: Aβ42/Aβ40 plasma ratio values were significantly lower in the Aβ‐PET positive than in the Aβ‐PET negative group (p<0.001). The opposite trend was observed for p‐tau181 plasma levels, which were significantly higher in the Aβ‐PET positive than in the Aβ‐PET negative group (p<0.001). The Aβ42/Aβ40 plasma ratio discriminated Aβ‐PET positivity with an AUC value of 0.87, performing identically to p‐tau181 plasma levels. A negligible increment in the AUC was observed after adjusting for ApoE genotype. However, inclusion of both biomarkers in the predictive model increased AUC value up to 0.94, outperforming each biomarker alone. Conclusion: Among the a‐MCI participants in the ABvac40 phase II clinical trial who had previously consent, the Aβ42/Aβ40 plasma ratio discriminates Aβ‐PET positivity with a high AUC, performing as well as p‐tau181. These results demonstrate that the Aβ42/Aβ40 ratio in plasma could be used to predict cerebral Aβ burden. [ABSTRACT FROM AUTHOR]

CBS domains are small protein motifs consisting of a three-stranded beta-sheet and two alpha-helices that are present in proteins of all kingdoms of life and in proteins with completely different functions. Several genetic diseases in humans have been associated with mutations in their sequence, which has made them promising targets for rational drug design. The C-terminal domain of the Methanococcus jannaschii protein MJ0100 includes a CBS-domain pair and has been overexpressed, purified and crystallized. Crystals of selenomethionine-substituted (SeMet) protein were also grown. The space group of both the native and SeMet crystals was determined to be orthorhombic P2(1)2(1)2(1), with unit-cell parameters a = 80.9, b = 119.5, c = 173.3 A. Preliminary analysis of the X-ray data indicated that there were eight molecules per asymmetric unit in both cases.

CBS domains are small protein motifs, usually associated in tandem, that are implicated in binding to adenosyl groups. Several genetic diseases in humans have been associated with mutations in CBS sequences, which has made them very promising targets for rational drug design. Trigonal crystals of the CBS-domain protein MJ0729 from Methanococcus jannaschii were grown by the vapour-diffusion method at acidic pH. Preliminary analysis of nine X-ray diffraction data sets using Yeates statistics and Britton plots showed that slight variation in the pH as well as in the buffer used in the crystallization experiments led to crystals with different degrees of merohedral twinning that may vary from perfect hemihedral twinning to perfect tetartohedral twinning.