Antimicrobial Peptides: The Production of Novel Peptide-Based Therapeutics in Plant Systems

The increased prevalence of antibiotic resistance is alarming and has a significant impact on the economies of emerging and underdeveloped nations. The redundancy of antibiotic discovery platforms (ADPs) and injudicious use of conventional antibiotics has severely impacted millions, across the globe. Potent antimicrobials from biological sources have been extensively explored as a ray of hope to counter the growing menace of antibiotic resistance in the population. Antimicrobial peptides (AMPs) are gaining momentum as powerful antimicrobial therapies to combat drug-resistant bacterial strains. The tremendous therapeutic potential of natural and synthesized AMPs as novel and potent antimicrobials is highlighted by their unique mode of action, as exemplified by multiple research initiatives. Recent advances and developments in antimicrobial discovery and research have increased our understanding of the structure, characteristics, and function of AMPs; nevertheless, knowledge gaps still need to be addressed before these therapeutic options can be fully exploited. This thematic article provides a comprehensive insight into the potential of AMPs as potent arsenals to counter drug-resistant pathogens, a historical overview and recent advances, and their efficient production in plants, defining novel upcoming trends in drug discovery and research. The advances in synthetic biology and plant-based expression systems for AMP production have defined new paradigms in the efficient production of potent antimicrobials in plant systems, a prospective approach to countering drug-resistant pathogens.

Cloning and homologous characterization of geranylgeranyl pyrophosphate synthase (GGPPS) from Withania somnifera revealed alterations in metabolic flux towards gibberellic acid biosynthesis

Overexpression of a novel geranylgeranyl pyrophosphate synthase gene (WsGGPPS) in planta resulted in increased levels of gibberellic acid and decrease in withanolide content. Withania somnifera (L.) Dunal, the herb from family Solanaceae is one of the most treasured medicinal plant used in traditional medicinal systems owing to its unique stockpile of pharmaceutically active secondary metabolites. Phytochemical and pharmacological studies in this plant were well established, but the genes affecting the regulation of biosynthesis of major metabolites were not well elucidated. In this study cloning and functional characterization of a key enzyme in terpenoid biosynthetic pathway viz. geranylgeranyl pyrophosphate synthase (EC 2.5.1.29) gene from Withania somnifera was performed. The full length WsGGPPS gene contained 1,104 base pairs that encode a polypeptide of 365 amino acids. The quantitative expression analysis suggested that WsGGPPS transcripts were expressed maximally in flower tissues followed by berry tissues. The expression levels of WsGGPPS were found to be regulated by methyl jasmonate (MeJA) and salicylic acid (SA). Amino acid sequence alignment and phylogenetic studies suggested that WsGGPPS had close similarities with GGPPS of Solanum tuberosum and Solanum pennellii. The structural analysis provided basic information about three dimensional features and physicochemical parameters of WsGGPPS protein. Overexpression of WsGGPPS in planta for its functional characterization suggested that the WsGGPPS was involved in gibberellic acid biosynthesis.

Trends of pharmaceutical design of Endophytes as anti-infective

Plant-endophyte associations represent an inexhaustible source of novel metabolites, exhibiting significance in environment, agriculture and pharmaceutical perspectives. The global outbreak of life threatening diseases necessitate a need for a more targeted approach through efficient drug-discovery programs. In recent times, endophytes as "bio-factories" have been extensively explored for the production of novel, bioactive metabolites demonstrating therapeutic properties. Resources in computational biology co-integrated with combinational chemistry have made significant contributions in this field, aiding in the discovery and screening of potential "drug-like" molecules from endophytes. The review provides a meta-analysis of bioactive metabolite production from endophytes, extensively discussing the bio-prospection of natural products for pharmaceutical applications. In light of the emerging importance of endophytes as anti-infective agents, an exploration of the pharmaceutical design of novel chemical entities and analogues has enabled efficient and cost-effective drug discovery programs. However, bottlenecks in endophyte biology and research require a better understanding of endophyte dynamics and mechanism of bioactive metabolite production towards a sustainable drug discovery program.

In silico mining and functional analysis of AP2/ERF gene in Withania somnifera

Withania somnifera owing to its strong and remarkable stress tolerance property is a reliable candidate for the determination of genes involved in mechanism of adaption/tolerance of various stress conditions. 187 AP2/ERF gene related transcripts (GRTs) were identified during comprehensive search in W. somnifera transcriptome repertoire. Major hits in homology search were observed from the model plant Arabidopsis and members of Solanaceae family. Cloning, expression analysis of the gene and genetic transient transformation with the gene (WsAP2) were performed to predict its functional role in planta. Enhanced expression of some of the pathway genes for terpenoid biosynthesis was observed in transformed tissues in comparison to the control tissues. It is speculated that WsAP2 gene crucially regulates the expression of GGPPS gene in addition to the regulation of other important genes of terpenoid pathway via induction of expression of other genes such as HMGR, CAS, DXS and DXR. To the best of our knowledge, this is the first report representing detailed study of AP2/ERF gene family in W. somnifera. It is also suggested from the study that gene might have role in eliciting responses to combat stress and attribute the strong stress tolerant property associated with the plant.

Retrograde response by reactive oxygen/nitrogen species in plants involving different cellular organelles

During oxidative and nitrosative stress conditions cellular organelles convey information to the nucleus to express specific sets of genes to withstand the stress condition and to reorganize their growth and developmental pattern. This organelle to nucleus communication is termed retrograde signaling. In the plant system chloroplast and peroxisomes are mainly involved with little involvement of mitochondria and other organelles in oxidative stress-mediated retrograde signaling. In this review, we will discuss retrograde signaling in plant systems with factors that regulate this signaling cascade.

Transcription factor repertoire in Ashwagandha (Withania somnifera) through analytics of transcriptomic resources: Insights into regulation of development and withanolide metabolism

Transcription factors (TFs) are important regulators of cellular and metabolic functions including secondary metabolism. Deep and intensive RNA-seq analysis of Withania somnifera using transcriptomic databases provided 3532 annotated transcripts of transcription factors in leaf and root tissues, belonging to 90 different families with major abundance for WD-repeat (174 and 165 transcripts) and WRKY (93 and 80 transcripts) in root and leaf tissues respectively, followed by that of MYB, BHLH and AP2-ERF. Their detailed comparative analysis with Arabidopsis thaliana, Capsicum annum, Nicotiana tabacum and Solanum lycopersicum counterparts together gave interesting patterns. However, no homologs for WsWDR representatives, LWD1 and WUSCHEL, were observed in other Solanaceae species. The data extracted from the sequence read archives (SRA) in public domain databases were subjected to re-annotation, re-mining, re-analysis and validation for dominant occurrence of WRKY and WD-repeat (WDR) gene families. Expression of recombinant LWD1 and WUSCHEL proteins in homologous system led to enhancements in withanolide content indicating their regulatory role in planta in the biosynthesis. Contrasting expression profiles of WsLWD1 and WsWUSCHEL provided tissue-specific insights for their participation in the regulation of developmental processes. The in-depth analysis provided first full-spectrum and comparative characteristics of TF-transcripts across plant species, in the perspective of integrated tissue-specific regulation of metabolic processes including specialized metabolism.

Adult 175 kDa collagenase antigen ofSetaria cerviin immunoprophylaxis againstBrugia malayiin jirds

A 175 kDa antigen fraction with collagenase activity was isolated and purified from somatic extracts of adultSetaria cervifemales using column chromatography involving consecutive steps of DEAE-Sepharose CL6B and Sephadex G-100. The optimum pH for 175 kDa collagenase was found to be pH 7.0. Sensitivities to a variety of inhibitors and activators indicated that the 175 kDa coIlagenolytic enzyme was metalloserine in nature. The enzyme hydrolysed a variety of protein substrates such as haemoglobin, casein, azocasein (general substrates) and collagen, FALGPA (furanoyl-acryloyl-leu-gly-pro-ala), the specific substrate of collagenase. The enzyme showed 57% inhibition by jird anti-somatic collagenase antibodies and reacted insignificantly with normal jird sera. Further analysis was undertaken on the immunoprophylactic potential of 175 kDa collagenase in inducing immunity againstBrugia malayi(a human filarial parasite) in jirds (Meriones unguiculatus)in vitroandin situ. Immune sera of jirds raised against this antigen promoted partial adherence of peritoneal exudate cells toB. malayimicrofilariae (mf) and infective larvae (L3)in vitroand induced partial cytotoxicity to the parasites within 48 h. The anti-S. cervi175 kDa antigen serum was more effective in inducing cytotoxicity toB. malayiL3, than mf. In the microchambers implanted inside immune jirds, host cells could migrate and adhere to the mf and infective larvae thereby killing them partially within 48 h.

Quantum drag forces on a sphere moving through a rarefied gas

As an application of quantum fluid mechanics, we consider the drag force exerted on a sphere by an ultradilute gas. Quantum mechanical diffraction scattering theory enters in that regime wherein the mean free path of a molecule in the gas is large compared with the sphere radius. The drag force is computed in a model specified by the "sticking fraction" of events in which a gaseous molecule is adsorbed by the spherical surface. Classical inelastic scattering theory is shown to be inadequate for physically reasonable sticking fraction values. The quantum mechanical scattering drag force is exhibited theoretically and compared with experimental data.

Effect of Momordica charantia Linn. pomous aqueous extract on cataractogenesis in murrin alloxan diabetics

The fruit extract of Momordica charantia Linn. was studied in Charles Foster rats of both sexes in respect of its dose-response hypoglycemia and at maximal effective dose, its influence on the development of diabetic cataract. Alloxan (120 mg/kg s.c./rat, single dose) diabetic rats with greater than 150 mg% of blood sugar were classified into four groups (n = 10) wherein two were control and the rest were test groups). In the test group, the oral dose response hypoglycemic herbal effect was found to be maximum at 4 g/kg/Day/rat when administered for 20 days. This dose was continued in the 2nd test group for a period of 2 months. Blood sugar in all the rats was estimated by microdetermination method using a dextrometer before and after therapy. The control group of rats received 2 ml of 0.9% NaCl and they developed cataract in 90 to 100 days. The herbal treated diabetics showed cataract in 140 to 180 days. Cataract formation was found to be dependant on blood sugar levels since the control group with blood sugar 307 +/- 81 (mg%) was blind 2 months earlier than herbal treated group which showed blood sugar 149 +/- 66.37 (mg%).

Glucose tolerance in patients with cerebrovascular accidents and their blood relatives

The present study was undertaken to examine whether there is any hereditary correlation, with reference to the abnormal glucose metabolism, between patients with cerebrovascular accidents and their healthy blood relatives in respect to the occurrence of cerebrovascular disease. The investigation was carried out by intravenous glucose tolerance test (IV-GTT) and prednisolone-primed glucose tolerance test (PP-GTT) in 83 subjects. Of these, 20 were healthy (control) persons (group A), matched in age and sex with 50 patients with cerebrovascular accidents (group B) and 13 family relatives of group B (group C) showing unequivocal GTT or PP-GTT. In controls, the IV-GTT criterion, i.e. k value, was found generally to be 2.82 +/- 0.43 and in persons less than 50 and over 50 years old, it was found to be related with age, i.e. 3.1 +/- 0.73 and 2.53 +/- 0.43, respectively. The 21 patients of group B with normal GTT response had a k value of 2.53 +/- 1.88 and the 29 patients with abnormal GTT response had a k value of 1.2 +/- 0.33. Among the 21 patients of group B, 11 had normal IV-GTT and their PP-GTT was found to be 125 +/- 12.5 mg%. The other 10 patients with abnormal IV-GTT exhibited a PP-GTT of 173.4 +/- 26.43 mg%. In 14 and 15 patients, the time-lapse difference of 7 and 8-21 days after stroke showed an abnormal GTT response and in 6 and 15 patients it showed a normal response. Among 13 healthy relatives of group B (group C), only 1 subject was found to have abnormal IV-GTT (k value of 1.386) and 2 were found to have abnormal PP-GTT (182.8 and 388.0 mg%), thus indicating pre-symptomatic diabetics.