Mucin induces CRISPR-Cas defence in an opportunistic pathogen

Parasitism by bacteriophages has led to the evolution of a variety of defense mechanisms in their host bacteria. However, it is unclear what factors lead to specific defenses being deployed upon phage infection. To explore this question, we exposed the bacterial fish pathogen Flavobacterium columnare to its virulent phage V156 in the presence of a eukaryotic host signal (mucin). All tested conditions led to some level of innate immunity, but the presence of mucin led to a dramatic increase in CRISPR spacer acquisition, especially in low nutrient conditions where over 60% of colonies had obtained at least one new spacer. Additionally, we show that the presence of a competitor bacterium further increases CRISPR spacer acquisition in F. columnare. These results suggest that ecological factors are important in determining defense strategies against phages, and that the concentration of phages on metazoan surfaces may select for the diversification of bacterial immune systems.

Characteristic Features and Signalling Cascade of Novel Zoonotic Coronavirus

The outbreak of coronavirus disease 2019 (COVID-19) due to its highly virulent nature has created a health crisis worldwide. It has attracted biologists’ attention to understand the morphology, host-pathogen interaction and signalling cascade at the core level. The whole world has come to a standstill due to the contagious nature and transmission rate of this virus. To understand the risk of COVID-19 outbreak across different parts of the globe it is crucial to provide a mechanistic framework for the interrelation of comorbidities. This review chapter focuses on the characteristic features, signalling cascade, and the interplay between pathogenesis and unfolded protein response in coronavirus. Due to the complexity of the coronavirus genome and its replication cycle, our understanding of structural, non-structural and accessory proteins in virion assembly and involvement of host machinery is significant. Thus, there is an urgent need to develop effective antiviral doses and vaccines against coronavirus. Hence, updating the detailed mechanism of cross-talk between virus and host, signal and receptor and the evasion of cellular innate immune responses is of utmost importance to develop novel therapeutic strategies.

Perceptual Data Embedding in Audio and Speech Signals

Perceptual embedding is a technique to embed extra information into multimedia signals without fidelity degradation, which is the core of many applications including watermarking and data hiding. Perceptual embedding can be viewed as a telecommunication to transmit the embedded information over the medium consisting of the host signal. This observation divides the current embedding techniques into two categories, i.e. the host-suppressing ones like the quantization-based Quantization Index Modulation (QIM) and Scalar Costa Scheme (SCS), and the non host-suppressing ones like the conventional Spread Spectrum (SS) technique. The former class has significant advantages over the latter in robustness and data rate due to significantly reduced noise levels. In this research, the conventional SS embedding technique is modified such that it can suppress the host impact mostly. Both the theoretical analysis and simulations show that the modification significantly improve the performance of the conventional scheme and further, outperform the QIM and SCS under the case of watermarking where the attacks can be expected to be very strong. To further increase the robustness and embedding rate, measures like frequency masking effects of the Human Masking Auditory system and Forward Error Correction schemes are employed, such as Turbo code. The second part of this research explores the possibility of high-capacity embedding in telephony speech signals. Another modification to improve the embedding rate is proposed for the conventional SS scheme under weak attacks, which are expected for the case of data embedding.

Perceptual Data Embedding in Audio and Speech Signals

Perceptual embedding is a technique to embed extra information into multimedia signals without fidelity degradation, which is the core of many applications including watermarking and data hiding. Perceptual embedding can be viewed as a telecommunication to transmit the embedded information over the medium consisting of the host signal. This observation divides the current embedding techniques into two categories, i.e. the host-suppressing ones like the quantization-based Quantization Index Modulation (QIM) and Scalar Costa Scheme (SCS), and the non host-suppressing ones like the conventional Spread Spectrum (SS) technique. The former class has significant advantages over the latter in robustness and data rate due to significantly reduced noise levels. In this research, the conventional SS embedding technique is modified such that it can suppress the host impact mostly. Both the theoretical analysis and simulations show that the modification significantly improve the performance of the conventional scheme and further, outperform the QIM and SCS under the case of watermarking where the attacks can be expected to be very strong. To further increase the robustness and embedding rate, measures like frequency masking effects of the Human Masking Auditory system and Forward Error Correction schemes are employed, such as Turbo code. The second part of this research explores the possibility of high-capacity embedding in telephony speech signals. Another modification to improve the embedding rate is proposed for the conventional SS scheme under weak attacks, which are expected for the case of data embedding.

TolCV1 Has Multifaceted Roles During Vibrio vulnificus Infection

RtxA1 is a major cytotoxin of Vibrio vulnificus (V. vulnificus) causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of V. vulnificus RtxA1 toxin. This study was conducted to further investigate the potential mechanisms of RpoS on RtxA1 secretion. First, V. vulnificus TolCV1 and TolCV2 proteins, two Escherichia coli TolC homologs, were measured at various time points by Western blotting. The expression of TolCV1 was increased time-dependently, whereas that of TolCV2 was decreased. Expression of both TolCV1 and TolCV2 was significantly downregulated in an rpoS deletion mutation. Subsequently, we explored the roles of TolCV1 and TolCV2 in V. vulnificus pathogenesis. Western blot analysis showed that RtxA1 toxin was exported by TolCV1, not TolCV2, which was consistent with the cytotoxicity results. Furthermore, the expression of TolCV1 and TolCV2 was increased after treatment of the host signal bile salt and the growth of tolCV1 mutant was totally abolished in the presence of bile salt. A tolCV1 mutation resulted in significant reduction of V. vulnificus induced-virulence in mice. Taken together, TolCV1 plays key roles in RtxA1 secretion, bile salt resistance, and mice lethality of V. vulnificus, suggesting that TolCV1 could be an attractive target for the design of new medicines to treat V. vulnificus infections.

Hybrid DNA Chaos Based Steganography on ECG Signal for Secured Data Communication

One of the principal issues in data sharing is security. Data being transferred on the internet is prone to severe attacks. Securing data is kind of digital privacy measures that are implemented to prevent the data to be hacked by unauthorized person while sharing the information over the communication network. Data may be of any form like image, signal or text. Encrypting the data before being transmitted is one step taken to promote security which is the well-known process of cryptography. Steganography deals with hiding the message in any unknown format. Combination of these methods turns to be more secure. A hybrid DNA hyper chaotic based algorithm with lifting wavelet technology to secure ECG signal is proposed here. The wavelet technique that decomposes the image into four bands namely LL, LH, HH, HL. To remove the redundancies the coefficients are utilised in the encoder process. The data hiding is implemented by selective embedding process is introduced in this method by determine host signal samples. The encrypted data then is hidden inside image using DNA method logically. When one knows and tries to get the hidden data they require the secret key to do so and any mistake in that leads to distortion of the signal which results in loss of data. This method is found to be secure and the simulation is done using MATLAB. A GUI is developed to choose the required ECG signal and other operations to embed the data and find the original signal after retrieval.

Imperceptible and Secure Blind Image Watermarking using Spread Spectrum Scheme with Adaptive Embedding Strength

Watermarking is the way toward concealing advanced mystery data in a picture. The best in class watermark implanting plans with the assistance of spread range and quantization, experiences Host Signal Interference (HSI) and scaling assaults, separately. They fixed the inserting parameter, which is hard to consider both power and subtlety for all pictures. This paper takes care of the issues by proposing a visually impaired watermarking strategy, Spread Spectrum Scheme with Adaptive Embedding Strength (SSAES). Their adaptiveness originates from the proposed Adaptive Embedding Strategy (AEP), which expands the installing quality or quantization limit by ensuring the Peak Signal-to-Noise Ratio (PSNR) of the host picture.SSAES includes free of HSI by calculating in the earlier information about HSI. We present a thought called mistake limit to hypothetically dissect the exhibition of our proposed techniques in detail. Further, to improve the security of the watermarked picture, the DCT coefficients are exposed to stage based encryption. This will improve the security of a watermarked picture. The test results reliably exhibit that SSAES outflank the best in class strategies regarding intangibility, power, computational expense, and flexibility. Along these lines the proposed course of action of picture watermarking routs the drawbacks of host signal impedance security ambushes and scaling attack.

Blind Audio Watermarking Based on Parametric Slant-Hadamard Transform and Hessenberg Decomposition

Digital watermarking has been widely utilized for ownership protection of multimedia contents. This paper introduces a blind symmetric audio watermarking algorithm based on parametric Slant-Hadamard transform (PSHT) and Hessenberg decomposition (HD). In our proposed algorithm, at first watermark image is preprocessed to enhance the security. Then, host signal is divided into non-overlapping frames and the samples of each frame are reshaped into a square matrix. Next, PSHT is performed on each square matrix individually and a part of this transformed matrix of size m×m is selected and HD is applied to it. Euclidean normalization is calculated from the 1st column of the Hessenberg matrix, which is further used for embedding and extracting the watermark. Simulation results ensure the imperceptibility of the proposed method for watermarked audios. Moreover, it is demonstrated that the proposed algorithm is highly robust against numerous attacks. Furthermore, comparative analysis substantiates its superiority among other state-of-the-art methods.

Transform Domain Digital Watermarking with Multiple Images as Watermarks

In this paper, a technique of image watermarking using multiple images as watermarks is presented. The technique is based on transform domain functions including discrete wavelet transform (DWT), discrete cosine transform (DCT) and singular value decomposition (SVD) with an image as the host signal i.e. the watermarks will be used as proofs of the authenticity of the host image. The technique is executed by performing multilevel DWT followed by applying DCT and SVD to both the host and watermark. Multiple watermarks are used for the insurance of better security level. The scheme is immune to common image processing operations & some attacks and exhibits PSNR of 108.3781dB, normalized cross correlation (NCC) over 0.99 and normalized correlation (NC) over 0.99.