Host-induced gene silencing of Pectobacterium carotovorum quorum sensing gene enhances soft rot disease resistance in potato plants

Quorum sensing is a regulatory mechanism of gene expression in bacteria which regulated many physiological processes such as production of virulence factors in Pectobacterium carotovorum. In this research, the plant expression vector, pBI121, harbouring the anti-quorum sensing gene, aiiA, was transformed into Potato (Solanum tuberosum cv. Agria) explants by Agrobacterium mediated transformation procedure and putative transformants containing pBI121/aiiA were obtained. The results of bioassay test revealed that the expression of aiiA gene in potato plant induces the resistance to the early stage of bacterium pathogenesis. The soft rot symptoms such as wilting, yellowing and tissue maceration were not observed until 48?hr after inoculation of transgenic potatoes with P. carotovorum. Although in non-transgenic plants, the disease symptoms were appeared after 24?hr of plants infection. Hence, this study proves that the heterologous expression of aiiA gene enhances the resistance against potato soft rot disease.     

Enzyme immobilization: an update

Compared to free enzymes in solution, immobilized enzymes are more robust and more resistant to environmental changes. More importantly, the heterogeneity of the immo-bilized enzyme systems allows an easy recovery of both enzymes and products, multiple re-use of enzymes, continuous operation of enzymatic processes, rapid termination of reactions, and greater variety of bioreactor designs. This paper is a review of the recent literatures on enzyme immobilization by various techniques, the need for immobilization and different applications in industry, covering the last two decades. The most recent papers, patents, and reviews on immobilization strategies and application are reviewed.     

Evaluating the effect of a mixture of two main conjugated linoleic acid isomers on hepatic steatosis in HepG2 cellular model

Molecular Biology Reports - Hepatic steatosis is an early form of non-alcoholic fatty liver disease (NAFLD), caused by abnormal fat deposition in the hepatocytes. Conjugated linoleic acid (CLA) is...     

Improved osteogenic differentiation of human induced pluripotent stem cells cultured on polyvinylidene fluoride/collagen/platelet-rich plasma composite nanofibers

Blood transfusion or blood products, such as plasma, have a long history in improving health, but today, platelet-rich plasma (PRP) is used in various medical areas such as surgery, orthopedics, and rheumatology in many ways. Considering the high efficiency of tissue engineering in repairing bone defects, in this study, we investigated the combined effect of nanofibrous scaffolds in combination with PRP on the osteogenic differentiation potential of human induced pluripotent stem cells (iPSCs). Electrospinning was used for fabricating nanofibrous scaffolds by polyvinylidene fluoride/collagen (PVDF/col) with and without PRP. After scaffold characterization, the osteoinductivity of the fabricated scaffolds was studied by culturing human iPSCs under osteogenic medium. The results showed that PRP has a considerable positive effect on the biocompatibility of the PVDF/col nanofibrous scaffold when examined by protein adsorption, cell attachment, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. In addition, the results obtained from alkaline phosphatase activity and calcium content assays demonstrated that nanofibers have higher osteoinductivity while grown on PRP-incorporated PVDF/col nanofibers. These results were also confirmed while the osteogenic differentiation of the iPSCs was more investigated by evaluating the most important bone-related genes expression level. According to the results, it can be concluded that PVDF/col/PRP has much more osteoinductivity while compared with the PVDF/col, and it can be introduced as a promising bone bio-implant for use in bone tissue engineering applications.     

Capturing the songs of mice with an improved detection and classification method for ultrasonic vocalizations (BootSnap)

House mice communicate through ultrasonic vocalizations (USVs), which are above the range of human hearing (>20 kHz), and several automated methods have been developed for USV detection and classification. Here we evaluate their advantages and disadvantages in a full, systematic comparison, while also presenting a new approach. This study aims to 1) determine the most efficient USV detection tool among the existing methods, and 2) develop a classification model that is more generalizable than existing methods. In both cases, we aim to minimize the user intervention required for processing new data. We compared the performance of four detection methods in an out-of-the-box approach, pretrained DeepSqueak detector, MUPET, USVSEG, and the Automatic Mouse Ultrasound Detector (A-MUD). We also compared these methods to human visual or ‘manual’ classification (ground truth) after assessing its reliability. A-MUD and USVSEG outperformed the other methods in terms of true positive rates using default and adjusted settings, respectively, and A-MUD outperformed USVSEG when false detection rates were also considered. For automating the classification of USVs, we developed BootSnap for supervised classification, which combines bootstrapping on Gammatone Spectrograms and Convolutional Neural Networks algorithms with Snapshot ensemble learning. It successfully classified calls into 12 types, including a new class of false positives that is useful for detection refinement. BootSnap outperformed the pretrained and retrained state-of-the-art tool, and thus it is more generalizable. BootSnap is freely available for scientific use.     

An improved cage system for the bioassay of Metarhizium anisopliae on Thrips tabaci (Thysanoptera: Thripidae)

The ability of thrips and other minute insects to escape from conventional assay cups led to development of a successful assay chamber. In the present study, we evaluated three bioassay systems for thrips; Tashiro cage, microtube assay and leaf sandwich assay and introduced an improved thrips entomopathogenic bioassay system (TEBS). Our objective was to investigate the effect of Metarhizium anisopliae on Thrips tabaci using an easy-to-use and inexpensive holding chamber that would produce bioassay results with acceptable levels of accuracy and precision. In our assays, we found that escape of second-instar larvae from TEBS was significantly less than those of other methods which we tested. Our results indicated that our assay system was more suitable than the other conventional assays for the bioassay of entomopathogenic fungi on T. tabaci.     

Design and In Silico Evaluation of a Novel Cyclic Disulfide-Rich anti-VEGF Peptide as a Potential Antiangiogenic Drug

International Journal of Peptide Research and Therapeutics - The vascular endothelial growth factor (VEGF) signaling pathway has a crucial role in regulating tumor angiogenesis. VEGF-A shows...     

Structure prediction of LDLR-HNP1 complex based on docking enhanced by LDLR binding 3D motif

Human antimicrobial peptides (AMPs), including defensins, have come under intense scrutiny owing to their key multiple roles as antimicrobial agents. Not only do they display direct action on microbes, but also recently they have been shown to interact with the immune system to increase antimicrobial activity. Unfortunately, since mechanisms involved in the binding of AMPs to mammalian cells are largely unknown, their potential as novel anti-infective agents cannot be exploited yet. Following the reported interaction of Human Neutrophil Peptide 1 dimer (HNP1) with a low density lipoprotein receptor (LDLR), a computational study was conducted to discover their putative mode of interaction. State-of-the-art docking software produced a set of LDLR-HNP1 complex 3D models. Creation of a 3D motif capturing atomic interactions of the LDLR binding interface allowed selection of the most plausible configurations. Eventually, only two models were in agreement with the literature. Binding energy estimations revealed that only one of them is particularly stable, but also interaction with LDLR weakens significantly bonds within the HNP1 dimer. This may be significant since it suggests a mechanism for internalisation of HNP1 in mammalian cells. In addition to a novel approach for complex structure prediction, this study proposes a 3D model of the LDLR-HNP1 complex which highlights the key residues which are involved in the interactions. The putative identification of the receptor binding mechanism should inform the future design of synthetic HNPs to afford maximum internalisation, which could lead to novel anti-infective drugs.