A flexible and visually meaningful multi-image compression, encryption and hiding scheme based on 2D compressive sensing.

Background: Encrypting plain images into noise-like cipher images is a common method in image encryption. However, when noise-like images appear in public networks, they are more likely to attract attention and suffer more cryptanalysis. To solve this problem, researchers propose the concept of visually meaningful image encryption scheme, which encrypts a plain image into a visually meaningful cipher image. Objective: In order to realize the visual security of cipher image and increase information capacity, this paper proposes a flexible visually secure multi-image compression, encryption and hiding scheme based on two-dimensional compressive sensing (2DCS), which can flexibly complete the compression and encryption of multiple plain images without increasing the amount of ciphertext data. Methods: The scheme is divided into encryption process and embedding process. In the encryption process, the plain image is randomly scrambled and non-linear gray value transformed to obtain a pre-encrypted integer matrix, then 2DCS is used to compress the pre-encrypted integer matrix to get the secret image. Repeat this process for multiple plain images to obtain multiple secret images. In the embedding process, integer wavelet transform and bit-plane decomposition are used to embed multiple secret images into the quantized coefficient matrix of host image to get the modified coefficient matrix, and then the inverse integer wavelet transform is used to transform the modified coefficient matrix into spatial space to get the visually meaningful cipher image. Result: The simulation experiment verifies the feasibility and effectiveness of the visually meaningful multi-image encryption scheme, and users can choose to improve the system's encryption capacity or cipher image's visual security according to their own needs.

Melatonin Attenuates Mitochondrial Damage in Aristolochic Acid-Induced Acute Kidney Injury.

Aristolochic acid (AA), extracted from Aristolochiaceae plants, plays an essential role in traditional herbal medicines and is used for different diseases. However, AA has been found to be nephrotoxic and is known to cause aristolochic acid nephropathy (AAN). AA-induced acute kidney injury (AKI) is a syndrome in AAN with a high morbidity that manifests mitochondrial damage as a key part of its pathological progression. Melatonin primarily serves as a mitochondria-targeted antioxidant. However, its mitochondrial protective role in AA-induced AKI is barely reported. In this study, mice were administrated 2.5 mg/kg AA to induce AKI. Melatonin reduced the increase in Upro and Scr and attenuated the necrosis and atrophy of renal proximal tubules in mice exposed to AA. Melatonin suppressed ROS generation, MDA levels and iNOS expression and increased SOD activities in vivo and in vitro. Intriguingly, the in vivo study revealed that melatonin decreased mitochondrial fragmentation in renal proximal tubular cells and increased ATP levels in kidney tissues in response to AA. In vitro, melatonin restored the mitochondrial membrane potential (MMP) in NRK-52E and HK-2 cells and led to an elevation in ATP levels. Confocal immunofluorescence data showed that puncta containing Mito-tracker and GFP-LC3A/B were reduced, thereby impeding the mitophagy of tubular epithelial cells. Furthermore, melatonin decreased LC3A/B-II expression and increased p62 expression. The apoptosis of tubular epithelial cells induced by AA was decreased. Therefore, our findings revealed that melatonin could prevent AA-induced AKI by attenuating mitochondrial damage, which may provide a potential therapeutic method for renal AA toxicity.

H2O2-Mediated Oxidative Stress Enhances Cystathionine γ-Lyase-Derived H2S Synthesis via a Sulfenic Acid Intermediate.

Hydrogen sulfide (H2S), which is generated mainly by cystathionine γ-lyase (CSE) in the cardiovascular system, plays a pivotal role in a wide range of physiological and pathological processes. However, the regulatory mechanism of the CSE/H2S system is poorly understood. Herein, we show that oxidation induces the disulfide bond formation between Cys252 and Cys255 in the CXXC motif, thus stimulating the H2S-producing activity of CSE. The activity of oxidized CSE is approximately 2.5 fold greater than that of the reduced enzyme. Molecular dynamics and molecular docking suggest that the disulfide bond formation induces the conformational change in the active site of CSE and consequently increases the affinity of the enzyme for the substrate L-cysteine. Mass spectrometry and mutagenesis studies further established that the residue Cys255 is crucial for oxidation sensing. Oxidative stress-mediated sulfenylation of Cys255 leads to a sulfenic acid intermediate that spontaneously forms an intramolecular disulfide bond with the vicinal thiol group of Cys252. Moreover, we demonstrate that exogenous hydrogen peroxide (H2O2) and endogenous H2O2 triggered by vascular endothelial growth factor (VEGF) promote cellular H2S production through the enhancement of CSE activity under oxidative stress conditions. By contrast, incubation with H2O2 or VEGF did not significantly enhance cellular H2S production in the presence of PEG-catalase, an enzymatic cell-permeable H2O2 scavenger with high H2O2 specificity. Taken together, we report a new posttranslational modification of CSE that provides a molecular mechanism for H2O2/H2S crosstalk in cells under oxidative stress.

Association of tau accumulation and atrophy in mild cognitive impairment: a longitudinal study.

OBJECTIVE: To examine the patterns of longitudinal tau accumulation and cortical atrophy and their association in subjects with mild cognitive impairment (MCI). METHODS: We collected 23 participants (60-89 years old, 11 males/12 females) with MCI from the Alzheimer's Disease Neuroimaging Initiative database. All participants underwent 18F flortaucipir (FTP) positron emission tomography (PET) and structural magnetic resonance imaging (MRI) scans at the baseline and follow-up visits (12-36 months). General linear models with covariates (baseline age, sex) were used to detect brain areas of significant tau accumulation and atrophy over time. Mediation analysis was employed to explore the potential reason for sequential biomarker changes in MCI progression, adjusting for baseline age, sex, and education level. RESULTS: Voxel-wise tau accumulation in MCI subjects was predominantly located in the inferior temporal cortex, middle temporal cortex, parietal cortex, posterior cingulate, precuneus, and temporoparietal regions (P < 0.001), and MRI atrophy included the inferior-middle temporal lobe, parietal lobe, and precuneus (P < 0.001). Longitudinal FTP accumulation was moderately associated with annualized MRI cortical atrophy (r = 0.409, 95% CI: 0.405-0.414, P < 0.01). Regional analyses indicated significant bivariate associations between annualized MRI cortical atrophy and FTP accumulation (baseline FTP cortical uptake and longitudinal FTP change). The results of the mediation analysis showed that the relationship between baseline FTP uptake and longitudinal cortical atrophy was partly mediated by the longitudinal FTP cortical change (indirect effect: 0.0107, P = 0.04). CONCLUSIONS: Our findings provide a preliminary description of the patterns of longitudinal FTP accumulation and annualized cortical atrophy in MCI progression, and MCI subjects with high tau binding levels show an increase risk of longitudinal tau accumulation, atrophy, and cognitive decline. Trial registration NCT00106899. Registered 1 April 2005, https://clinicaltrials.gov/ct2/show/study/NCT00106899.

Chiayiivirga flava gen. nov., sp. nov., a novel bacterium of the family Xanthomonadaceae isolated from an agricultural soil, and emended description of the genus Dokdonella.

A novel Gram-reaction-negative, yellow-pigmented, aerobic, non-motile and rod-shaped bacterium designated strain CC-YHH031(T) was isolated from an agricultural soil collected at Chiayi County, Taiwan. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CC-YHH031(T) formed a discrete monophyletic lineage in the family Xanthomonadaceae, sharing high pairwise sequence similarity of 93.5-95.2 and 94.8% with species of the genus Dokdonella (94.9% similarity to the type strain of the type species) and Aquimonas voraii GPTSA 20(T), respectively. The genomic DNA G+C content of strain CC-YHH031(T) was 68.6 ± 0.7 mol% and the predominant respiratory quinone was ubiquinone Q-8. Spermidine was the principal polyamine, with minor amounts of putrescine. Major fatty acids (>5% of total fatty acids) were iso-C(16:00, iso-C(15:0), C(16:1)ω7c and/or C(16:1)ω6c (summed feature 3), iso-C(17:1)ω9c, iso-C(14:0), iso-C(11:0) and iso-C(11:0) 3-OH. The polar lipid profile of strain CC-YHH031(T) included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, two unidentified aminophospholipids (APL1-2) and four unidentified phospholipids (PL1-4). Strain CC-YHH031(T) was distinguished particularly from the type species of the genus Dokdonella (Dokdonella koreensis) by the presence of major amounts of iso-C(14:0) and summed feature 3 and minor amounts of iso-C(17:0) and by the complete absence of anteiso-C(17:0), the presence of PL1-3 and APL1-2, the absence of APL3 and the presence of putrescine in the former. On the basis of distinguishing genotypic and phenotypic evidence, strain CC-YHH031(T) is proposed to represent a novel genus and species within the family Xanthomonadaceae, for which the name Chiayiivirga flava gen. nov., sp. nov. is proposed. The type strain of Chiayiivirga flava is CC-YHH031(T) ( =BCRC 80274(T) =DSM 24163(T)).

Azospirillum formosense sp. nov., a diazotroph from agricultural soil.

A gram-negative, spiral or rod-shaped, non-spore-forming diazotrophic bacterium, designated CC-Nfb-7(T), was isolated from agricultural soil in Yunlin County, Taiwan. 16S rRNA gene sequence analysis showed that strain CC-Nfb-7(T) was most closely related to Azospirillum brasilense DSM 1690(T) (97.4 % 16S rRNA gene sequence similarity), Azospirillum rugosum IMMIB AFH-6(T) (96.8 %) and Azospirillum oryzae JCM 21588(T) (96.6 %); <96.5 % 16S rRNA gene sequence similarity was found with all other members of the genus Azospirillum. DNA-DNA relatedness between strain CC-Nfb-7(T) and A. brasilense DSM 1690(T), A. rugosum DSM 19657(T) and A. oryzae JCM 21588(T) was 38.9, 30.1 and 31.8 %, respectively. The respiratory quinone was ubiquinone Q-10. The major fatty acids were summed feature 8 (consisting of C(18 : 1)ω7c and/or C(18 : 1)ω6c), summed feature 3 (consisting of C(16 : 1)ω7c and/or C(16 : 1)ω6c), summed feature 2 (consisting of C(14 : 0) 3-OH and/or iso-C(16 : 1) I), C(16 : 0), C(18 : 0) 2-OH and C(16 : 0) 3-OH. The polar lipids consisted mainly of phosphatidylglycerol, phosphatidylcholine and one unidentified phospholipid. Furthermore, moderate amounts of phosphatidylethanolamine, phosphatidyldimethylethanolamine and one unidentified aminophospholipid were also detected. Strain CC-Nfb-7(T) could be distinguished from members of phylogenetically related species by differences in phenotypic properties. On the basis of morphological, chemotaxonomic and phylogenetic data, strain CC-Nfb-7(T) represents a novel species within the genus Azospirillum, for which we propose the name Azospirillum formosense sp. nov. The type strain is CC-Nfb-7(T) ( = BCRC 80273(T) = JCM 17639(T) = DSM 24137(T)).

Sphingomonas formosensis sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium isolated from agricultural soil.

In the present study, a yellow-pigmented, Gram-negative, short rod-shaped novel bacterium that was capable of degrading a wide range of polycyclic aromatic hydrocarbons (naphthalene, phenanthrene and pyrene) was isolated from agricultural soil located in Yunlin County, Taiwan. Comparative 16S rRNA gene sequence analysis positioned the novel strain in the genus Sphingomonas as an independent lineage adjacent to a subclade containing Sphingomonas fennica K101(T), Sphingomonas histidinilytica UM2(T), Sphingomonas wittichii RW1(T) and Sphingomonas haloaromaticamans A175(T). 16S rRNA gene sequence analysis of strain CC-Nfb-2(T) showed highest sequence similarity to S. fennica K101(T) (96.2%), S. histidinilytica UM2(T) (96.1%), S. wittichii RW1(T) (95.9%), S. haloaromaticamans A175(T) (95.7%), and Sphingobium ummariense RL-3(T) (94.7%); lower sequence similarities were observed with strains of all other Sphingomonas species. The strain contained phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid and diphosphatidylglycerol. The predominant fatty acids were summed feature 8 (C(18:1)ω7c and/or C(18:1)ω6c) C(16:0) and 11-methyl C(18:1)ω7c; C(14:0) 2-OH was the major 2-hydroxy fatty acid. Previously, these lipids have been found to be characteristic of members of the genus Sphingomonas. The serine palmitoyl transferase gene (spt) was also detected and sphingolipid synthesis was confirmed. The predominant isoprenoid quinone system was ubiquinone (Q-10) and the isolate contained sym-homospermidine as the major polyamine. The DNA G+C content of the isolate was 62.8±0.8 mol%. On the basis of chemotaxonomic, phenotypic and phylogenetic data, strain CC-Nfb-2(T) represents a novel species within the genus Sphingomonas, for which the name Sphingomonas formosensis sp. nov. is proposed; the type strain is CC-Nfb-2(T) (=BCRC 80272(T)=DSM 24164(T)).