In silico designing and characterization of outer membrane protein K (OmpK) from Vibrio anguillarum and its expression in Nicotiana tabacum for the development of a plant-based vaccine against fish vibriosis.

Vibriosis is caused by Vibrio anguillarum in various species of aquaculture. A novel, secure, and stable vaccine is needed to eradicate vibriosis. Here, for reverse vaccinology and plant-based expression, the outer membrane protein K (OmpK) of V. anguillarum was chosen due to its conserved nature in all Vibrio species. OmpK, an ideal vaccine candidate against vibriosis, demonstrated immunogenic, non-allergic, and non-toxic behavior by using various bioinformatics tools. Docking showed the interaction of the OmpK model with TLR-5. In comparison to costly platforms, plants can be used as alternative and economic bio-factories to produce vaccine antigens. We expressed OmpK antigen in Nicotiana tabacum using Agrobacterium-mediated transformation. The expression vector was constructed using Gateway® cloning. Transgene integration was verified by polymerase chain reaction (PCR), and the copy number via qRT-PCR, which showed two copies of transgenes. Western blotting detected monomeric form of OmpK protein. The total soluble protein (TSP) fraction of OmpK was equivalent to 0.38% as detected by ELISA. Mice and fish were immunized with plant-derived OmpK antigen, which showed a significantly high level of anti-OmpK antibodies. The present study is the first report of OmpK antigen expression in higher plants for the potential use as vaccine in aquaculture against vibriosis, which could provide protection against multiple Vibrio species due to the conserved nature OmpK antigen.

Plastidial Expression of 3ß-Hydroxysteroid Dehydrogenase and Progesterone 5ß-Reductase Genes Confer Enhanced Salt Tolerance in Tobacco.

The short-chain dehydrogenase/reductase (SDR) gene family is widely distributed in all kingdoms of life. The SDR genes, 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and progesterone 5-ß-reductases (P5ßR1, P5ßR2) play a crucial role in cardenolide biosynthesis pathway in the Digitalis species. However, their role in plant stress, especially in salinity stress management, remains unexplored. In the present study, transplastomic tobacco plants were developed by inserting the 3ß-HSD, P5ßR1 and P5ßR2 genes. The integration of transgenes in plastomes, copy number and transgene expression at transcript and protein level in transplastomic plants were confirmed by PCR, end-to-end PCR, qRT-PCR and Western blot analysis, respectively. Subcellular localization analysis showed that 3ß-HSD and P5ßR1 are cytoplasmic, and P5ßR2 is tonoplast-localized. Transplastomic lines showed enhanced growth in terms of biomass and chlorophyll content compared to wild type (WT) under 300 mM salt stress. Under salt stress, transplastomic lines remained greener without negative impact on shoot or root growth compared to the WT. The salt-tolerant transplastomic lines exhibited enhanced levels of a series of metabolites (sucrose, glutamate, glutamine and proline) under control and NaCl stress. Furthermore, a lower Na+/K+ ratio in transplastomic lines was also observed. The salt tolerance, mediated by plastidial expression of the 3ß-HSD, P5ßR1 and P5ßR2 genes, could be due to the involvement in the upregulation of nitrogen assimilation, osmolytes as well as lower Na+/K+ ratio. Taken together, the plastid-based expression of the SDR genes leading to enhanced salt tolerance, which opens a window for developing saline-tolerant plants via plastid genetic engineering.

Chloroplast-based inducible expression of ESAT-6 antigen for development of a plant-based vaccine against tuberculosis.

Mycobacterium tuberculosis causes tuberculosis in humans. The major disease burden of tuberculosis lies in developing countries. Lack of an effective vaccine for adults is one of the major hurdles for controlling this deadly disease. In the present study, 6 kDa early secretory antigenic target (ESAT-6) of M. tuberculosis was inducibly expressed in chloroplasts of Nicotiana tabacum. The expression of ESAT-6 in chloroplasts was controlled by T7 promoter that was activated by nuclear-generated signal peptide. Tobacco plants, containing nuclear component, were transformed via biolistic bombardment with pEXP-T7-ESAT-6 obtained by Gateway® cloning. Transformation and homoplasmic status of transplastomic plants was confirmed by polymerase chain reaction and Southern blotting. Plants were induced for protein expression by spraying with 5% ethanol for 1 day, 3 days, 7 days and 10 days. ESAT-6 protein was detected by immunoblot analysis and maximum protein was obtained for 10 days induced plants that was estimated to accumulate up to 1.2% of total soluble fraction of protein. Transplastomic plants showed completely normal morphology. Transplastomic and untransformed plants became slightly chlorotic upon prolonged exposure to ethanol until 10 days. Taken together, this data could help in the development of an antigen-based subunit vaccine against tuberculosis.

Interplay of N acetyl cysteine and melatonin in regulating oxidative stress-induced cardiac hypertrophic factors and microRNAs.

Early and specific diagnosis of oxidative stress linked diseases as cardiac heart diseases remains a major dilemma for researchers and clinicians. MicroRNAs may serve as a better tool for specific early diagnostics and propose their utilization in future molecular medicines. We aimed to measure the microRNAs expressions in oxidative stress linked cardiac hypertrophic condition induced through stimulants as Endothelin and Isoproterenol. Cardiac hypertrophic animal models were confirmed by BNP, GATA4 expression, histological assays, and increased cell surface area. High oxidative stress (ROS level) and decreased antioxidant activities were assessed in hypertrophied groups. Enhanced expression of miR-152, miR-212/132 while decreased miR-142-3p expression was observed in hypertrophic condition. Similar pattern of these microRNAs was detected in HL-1 cells treated with H2O2. Upon administration of antioxidants, the miRNAs expression pattern altered from that of the cardiac hypertrophied model. Present investigation suggests that oxidative stress generated during the cardiac pathology may directly or indirectly regulate anti-hypertrophy pathway elements through microRNAs including antioxidant enzymes, which need further investigation. The down-regulation of free radical scavengers make it easier for the oxidative stress to play a key role in disease progression.