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We detected African swine fever virus (ASFV) from a wild boar in Singapore. In

Abstract Aquatic viruses are major threats to global aquacultural productivity. While conventional diagnostic methods for disease investigation are laborious, time‐consuming, and often involve the sacrifice of animals, environmental DNA and RNA (eDNA/eRNA) tools have the potential in being non‐invasive alternatives for the effective and early detection of various pathogens simultaneously. In this study, three seawater filtration methods—Sterivex syringe filtration, centrifugal ultrafiltration, and vacuum pump filtration with iron flocculation—were assessed for the recovery rates in co‐detecting fish virus eDNA/eRNA from natural seawater that was spiked with fish red seabream iridovirus (RSIV, DNA virus) and nervous necrosis virus (NNV, RNA virus). The centrifugal ultrafiltration method was the most effective for the capture of small‐sized viruses like NNV with a recovery rate of 63.23%, while the method of vacuum pump filtration with iron flocculation and chloroform disintegration of filter membranes had the highest RSIV recovery rate of 32.61%. We also optimized both automated and manual nucleic acid extraction methods and found comparable eDNA/eRNA extraction efficiencies. Our findings from the systematic comparison of seawater filtration and extraction methods suggest that each seawater filtration/nucleic acid extraction method can cater to different aquatic animal virus surveillance and disease investigation scenarios. These highlight the potential of virus eDNA/eRNA approaches for advancing the field of disease ecology and safeguarding aquatic animal health.

Abstract Background Tapeworms are agents of neglected tropical diseases responsible for significant health problems and economic loss. They also exhibit adaptations to a parasitic lifestyle that confound comparisons of their development with other animals. Identifying the genetic factors regulating their complex ontogeny is essential to understanding unique aspects of their biology and for advancing novel therapeutics. Here we use RNA sequencing to identify up-regulated signalling components, transcription factors and post-transcriptional/translational regulators (genes of interest, GOI) in the transcriptomes of Larvae and different regions of segmented worms in the tapeworm Hymenolepis microstoma and combine this with spatial gene expression analyses of a selection of genes. Results RNA-seq reads collectively mapped to 90% of the > 12,000 gene models in the H. microstoma v.2 genome assembly, demonstrating that the transcriptome profiles captured a high percentage of predicted genes. Contrasts made between the transcriptomes of Larvae and whole, adult worms, and between the Scolex-Neck, mature strobila and gravid strobila, resulted in 4.5–30% of the genes determined to be differentially expressed. Among these, we identified 190 unique GOI up-regulated in one or more contrasts, including a large range of zinc finger, homeobox and other transcription factors, components of Wnt, Notch, Hedgehog and TGF-β/BMP signalling, and post-transcriptional regulators (e.g. Boule, Pumilio). Heatmap clusterings based on overall expression and on select groups of genes representing ‘signals’ and ‘switches’ showed that expression in the Scolex-Neck region is more similar to that of Larvae than to the mature or gravid regions of the adult worm, which was further reflected in large overlap of up-regulated GOI. Conclusions Spatial expression analyses in Larvae and adult worms corroborated inferences made from quantitative RNA-seq data and in most cases indicated consistency with canonical roles of the genes in other animals, including free-living flatworms. Recapitulation of developmental factors up-regulated during larval metamorphosis suggests that strobilar growth involves many of the same underlying gene regulatory networks despite the significant disparity in developmental outcomes. The majority of genes identified were investigated in tapeworms for the first time, setting the stage for advancing our understanding of developmental genetics in an important group of flatworm parasites.

Quorum sensing is a system of stimuli and responses in relation to bacterial cell population density that regulates gene expression, including virulence determinants. Consequently, quorum sensing has been an attractive target for the development of novel anti-infective measures that do not rely on the use of antibiotics. Anti-quorum sensing has been a promising strategy to combat bacterial infections as it is unlikely to develop multidrug resistant pathogens since it does not impose any selection pressure. A number of anti-quorum sensing approaches have been documented and plant-based natural products have been extensively studied in this context. Plant matter is one of the major sources of chemicals in use today in various industries, ranging from the pharmaceutical, cosmetic, and food biotechnology to the textile industries. Just like animals and humans, plants are constantly exposed to bacterial infections, it is therefore logical to expect that plants have developed sophisticated of chemical mechanisms to combat pathogens. In this review, we have surveyed the various types of plant-based natural products that exhibit anti-quorum sensing properties and their anti-quorum sensing mechanisms.

Quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. In this work, we screened edible, endemic plants in Malaysia for anti-quorum sensing properties. Extracts from Melicope lunu-ankenda (Gaertn.) T. G. Hartley, a Malay garden salad, inhibited response of Chromobacterium violaceum CV026 to N-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of E. coli [pSB401], disrupted pyocyanin synthesis, swarming motility and expression of lecA::lux of Pseudomonas aeruginosa PAO1. Although the chemical nature of the anti-QS compounds from M. lunu-ankenda is currently unknown, this study proves that endemic Malaysian plants could serve as leads in the search for anti-quorum sensing compounds.

We detected African swine fever virus (ASFV) from a wild boar in Singapore. In <72 hours, we confirmed and reported ASFV p72 genotype II, CD2v serogroup 8, and IGR-II variant by using a combination of real-time PCR and whole-genome sequencing. Continued biosurveillance will be needed to monitor ASFV in Singapore. [ABSTRACT FROM AUTHOR]

N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography–mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach. [ABSTRACT FROM AUTHOR]

Quorum sensing is a system of stimuli and responses in relation to bacterial cell population density that regulates gene expression, including virulence determinants. Consequently, quorum sensing has been an attractive target for the development of novel anti-infective measures that do not rely on the use of antibiotics. Anti-quorum sensing has been a promising strategy to combat bacterial infections as it is unlikely to develop multidrug resistant pathogens since it does not impose any selection pressure. A number of anti-quorum sensing approaches have been documented and plant-based natural products have been extensively studied in this context. Plant matter is one of the major sources of chemicals in use today in various industries, ranging from the pharmaceutical, cosmetic, and food biotechnology to the textile industries. Just like animals and humans, plants are constantly exposed to bacterial infections, it is therefore logical to expect that plants have developed sophisticated of chemical mechanisms to combat pathogens. In this review, we have surveyed the various types of plant-based natural products that exhibit anti-quorum sensing properties and their anti-quorum sensing mechanisms. [ABSTRACT FROM AUTHOR]

Various parts of Piper nigrum, Piper betle and Gnetum gnemon are used as food sources by Malaysians. The purpose of this study is to examine the anti-quorum sensing (anti-QS) properties of P. nigrum, P. betle and G. gnemon extracts. The hexane, chloroform and methanol extracts of these plants were assessed in bioassays involving Pseudomonas aeruginosa PA01, Escherichia coli [pSB401], E. coli [pSB1075] and Chromobacterium violaceum CV026. It was found that the extracts of these three plants have anti-QS ability. Interestingly, the hexane, chloroform and methanol extracts from P. betle showed the most potent anti-QS activity as judged by the bioassays. Since there is a variety of plants that serve as food sources in Malaysia that have yet to be tested for anti-QS activity, future work should focus on identification of these plants and isolation of the anti-QS compounds. [ABSTRACT FROM AUTHOR]

Quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. In this work, we screened edible, endemic plants in Malaysia for anti-quorum sensing properties. Extracts from Melicope lunu-ankenda (Gaertn.) T. G. Hartley, a Malay garden salad, inhibited response of Chromobacterium violaceum CV026 to N-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of E. coli [pSB401], disrupted pyocyanin synthesis, swarming motility and expression of lecA::lux of Pseudomonas aeruginosa PAO1. Although the chemical nature of the anti-QS compounds from M. lunu-ankenda is currently unknown, this study proves that endemic Malaysian plants could serve as leads in the search for anti-quorum sensing compounds. [ABSTRACT FROM AUTHOR]

We investigate the reconstruction of bandlimited signals in the linear canonical transform (LCT) domain from a finite set of nonuniformly spaced samples. Based on the reproducing property of the reproducing kernel belonging to the class of bandlimited signals in LCT domain, we derive an interpolating formula with minimum mean-squared error that interpolates the finite set of nonuniformly spaced samples, and show that it is identical to the minimum energy bandlimited in LCT domain interpolator. Singular value decomposition is also used to set up a reconstruction algorithm which guarantees that the reconstruction result also achieves the minimum energy reconstruction. [ABSTRACT FROM AUTHOR]

We first show that the bandlimited signals associated with linear canonical transform (LCT) form a reproducing kernel Hilbert space. An orthogonal basis for the class of bandlimited signals associated with LCT is then proposed by use of the reproducing kernel, with respect to which the coordinates of signal are actually values taken by the signal at certain instants of time. Finally, a nonuniform sampling theorem for bandlimited signals associated with LCT is presented. [ABSTRACT FROM AUTHOR]

A new expression of the scintillation index (SI) for a Gaussian-beam wave propagating through moderate-to-strong non-Kolmogorov turbulence is derived, using a generalized effective atmospheric spectrum and the extended Rytov approximation theory. Finite inner and outer scale parameters and high wave number “bump” are considered in the spectrum with a generalized spectral power law in the range of 3–4, instead of the fixed classical Kolmogorov power law of 11/3. The obtained SI expression is then used to analyze the effects of the spectral power law and the inner scale and outer scale on SI under various non-Kolmogorov fluctuation conditions. These results will be useful in future investigations of optical wave propagation through atmospheric turbulence. [ABSTRACT FROM AUTHOR]

Ischemic stroke is a major cause of mortality and disability and has become a significant public health concern among women. Overall, women have more ischemic stroke events than men, in part due to their longer life span, and also suffer from more severe stroke-related disabilities compared to men. Women are also more likely than men to present with atypical non-focal neurological symptoms, potentially leading to delayed diagnosis and treatment. Female-specific risk factors, especially those related to pregnancy, are often under-recognized. A woman’s risk for ischemic stroke evolves throughout her lifespan, influenced by various factors including the age of menarche, pregnancy and its complications (such as parity, pre-eclampsia/eclampsia, and preterm delivery), postpartum challenges, oral contraceptive use, and menopause. Additionally, vascular risk factors like hypertension, diabetes, and atrial fibrillation are more prevalent among older women. Despite comparable treatment efficacies, women generally experience poorer outcomes after stroke. They also face higher rates of post-stroke depression, further complicating recovery. Although significant strides have been made in reducing the incidence of ischemic stroke, our understanding of the unique risks, underlying causes, and long-term consequences for women remains limited. While sex hormones may explain some differences, a lack of awareness regarding sex-related disparities can result in suboptimal care. This review aims to illuminate the unique risks and burdens of ischemic stroke faced by women, advocating for a more nuanced understanding to enhance prevention and treatment strategies.

We demonstrate that the GaAs/AlGaAs nanowires (NWs) ensemble is fabricated into photo-detectors. Current–voltage (I–V) characteristics are measured on GaAs/AlGaAs core–shell ensemble NW photo-detectors at room-temperature before and after 1-MeV proton irradiation with fluences from cm to cm. The degradation of photocurrent suggests that the point defects induced by proton radiation could cause both carrier lifetime and carrier mobility to decrease synchronously. Comparing with a GaAs quantum well, the degradations of light and dark current for the irradiated NWs photo-detector indicate that NWs material is a preferable potential candidate for space applications. [ABSTRACT FROM AUTHOR]

To gain a physical insight into the radiation effect on nanowires (NWs), the time resolved photoluminescence (TRPL) technique is used to investigate the carrier dynamic behaviors in GaAs/AlGaAs core–shell NWs before and after 1-MeV proton irradiation with fluences ranging from cm to cm. It is found that the degradations of spectral peak intensity and minority carrier lifetime show similar trends against irradiation fluence, which is closely related to the displacement defects induced by irradiation. We also find that the proton irradiation-induced defects behave as Shockley–Read–Hall (SRH) recombination center trapping free carriers. Finally, the defect concentration could be estimated through measuring the minority carrier lifetime. [ABSTRACT FROM AUTHOR]

Based on the modified spectrum, the analytic expressions for the variance and normalized covariance of angle-of-arrival (AOA) fluctuations are presented, which are applicable to the weak and strong regimes. The experimental data of AOA fluctuations validate the new derived expressions in weak and strong regimes. The results show that the receiving aperture D, outer scale and cell scale larger than the scattering disc S contribute significantly to the AOA fluctuations, and contributions from the small-scale turbulence are negligible. For the case of 4S/D ≥ 1, the receiving aperture dominates low-pass filtering effects and the new displacement variances are in good agreement with the results from the old weak-fluctuation theory. For the case of 4S/D ≥ 1, the scattering disc dominates the low-pass filtering effects and the new displacement variances depart from the results from the old weak-fluctuation theory. [ABSTRACT FROM AUTHOR]