Evolutionary Implications and Physicochemical Analyses of Selected Proteins of Type III Polyketide Synthase Family

Type III polyketide synthases have a substantial role in the biosynthesis of various polyketides in plants and microorganisms. Comparative proteomic analysis of type III polyketide synthases showed evolutionarily and structurally related positions in a compilation of amino acid sequences from different families. Bacterial and fungal type III polyketide synthase proteins showed <50% similarity but in higher plants, it exhibited >80% among chalcone synthases and >70% in the case of non-chalcone synthases. In a consensus phylogenetic tree based on 1000 replicates; bacterial, fungal and plant proteins were clustered in separate groups. Proteins from bryophytes and pteridophytes grouped immediately near to the fungal cluster, demonstrated how evolutionary lineage has occurred among type III polyketide synthase proteins. Upon physicochemical analysis, it was observed that the proteins localized in the cytoplasm and were hydrophobic in nature. Molecular structural analysis revealed comparatively stable structure comprising of alpha helices and random coils as major structural components. It was found that there was a decline in the structural stability with active site mutation as prophesied by the in silico mutation studies

Recent studies on well-known spice, <i>Piper longum</i> Linn.

222-227The fruits of Piper longum Linn. are very well-known medicine for diseases of the respiratory tract, viz. cough, bronchitis, asthma, etc.; as counter-irritant, analgesic when applied locally for muscular pains and inflammation and as general tonic and hematinic. They are carminative and known to enhance the bioavailability of food and drugs. In this paper recently developed micropropagation method by tissue culture and molecular basis of genotypic differentiation between the male and female plants, using Randomly Amplified Polymorphic DNA (RAPD) technique and development of sex associated DNA markers have been discussed along with some medicinal and pharmacological properties of the spice

Screening of phytochemicals from selected plants with antifungal properties against RXLR effector protein Avr3a11in Phytophthora capsici

Phytophthora Capsici is a fungal plant pathogen which causes significant damage to broad range of commercial &amp; medicinally valuable plants like black pepper, tomato, watermelon, etc. Chemical compounds like fungicides are commonly used against Phytophthora infections. Prolonged inhalation of fungicides by humans, leads to neural &amp; visual disturbances &amp; lung infections. They can also permanently silence or reprogram normal genes that last for several generations &amp; are very harmful to the environment too. An alternative to chemical control of fungal pathogens is by introducing phytochemicals, which are potentially active against Phytophthora capsici. The study involves computational screening of phytochemicals with antifungal activity of plants against Avr3a11 in P. Capsici. Avr3a11 is an RXLR effector protein which functions as a virulence factor when recognised by plant immune receptors. The functional domain in Avr3a11 interacts with Resistance (R) proteins of the plant thereby triggering ETI (Effector Triggered Immunity) in plants. The phytochemicals from Turmeric, Garlic and Neem were used as ligand molecules. The 3D structure of Avr3a11 was retrieved from PDB (PDB id: 3ZR8) &amp; the ligand structures collected from PubChem. Molecular docking was carried out in Discovery studio package to assess the binding energy of the phytochemicals with Avr3a11 in its functional domain. The phytochemical Alliin from garlic showed significant binding interactions with the target-Avr3a11 compared to the commonly used fungicides, indicating that Alliin can act as a potential inhibitor of Avr3a11. An in vitro assay of the plant extracts on phytohthora capsici also gives a validation of the docking study. This study provides insight into the potential use of phytochemicals to effectively combat the Phytophthora infections in plants

<i>In silico</i> approaches illustrate the evolutionary pattern and protein-small molecule interactions of quinolone synthase from <i>Aegle marmelos</i> Correa

<p>Quinolone synthase from <i>Aegle marmelos</i> (AmQNS) is a Rutacean-specific plant type III polyketide synthase that synthesizes quinolone, acridone, and benzalacetone with therapeutic potential. Simple architecture and broad substrate affinity of AmQNS make it as one of the target enzymes to produce novel structural scaffolds. Another unique feature of AmQNS despite its high similarity to acridone forming type III polyketide synthase from <i>Citrus microcarpa</i> is the variation in the product formation. Hence, to explore the characteristic features of AmQNS, an in-depth sequence and structure-based bioinformatics analyses were performed. Our studies indicated that AmQNS and its nearest homologs have evolved by a series of gene duplication events and strong purifying selection pressure constrains them in the evolutionary process. Additionally, some amino acid alterations were identified in the functionally important region(s), which can contribute to the functional divergence of the enzyme. Prediction of favorable amino acid substitutions will be advantageous in the metabolic engineering of AmQNS for the production of novel compounds. Furthermore, comparative modeling and docking studies were utilized to investigate the structural behavior and small molecule interaction pattern of AmQNS. The observations and results reported here are crucial for advancing our understanding of AmQNS’s phylogenetic position, selection pressure, evolvability, interaction pattern and thus providing the foundation for further studies on the structural and reaction mechanism.</p

In vitro morphogenesis and cell suspension culture establishment in Piper solmsianum C. DC. (Piperaceae)

In vitro morphogenesis and cell suspension culture establishment in Piper solmsianum C. DC. (Piperaceae)). Piper solmsianum is a shrub from Southeast Brazil in which many biologically active compounds were identified. The aim of this work was to establish a cell suspension culture system for this species. With this in mind, petiole and leaf explants obtained from in vitro plantlets were cultured in the presence of different plant growth regulator combinations (IAA, NAA, 2,4-D and BA). Root and indirect shoot adventitious formation, detected by histological analysis, was observed. Besides the different combinations of plant growth regulators, light regime and the supplement of activated charcoal (1.5 mg.l(-1)) were tested for callus induction and growth. Cultures maintained in light, on a 0.2 mg.l(-1) 2,4-D and 2 mg.l(-1) BA supplemented medium, and in the absence of activated charcoal, showed the highest calli fresh matter increment. From a callus culture, cell suspension cultures were established and their growth and metabolite accumulation studied. The achieved results may be useful for further characterization of the activated secondary metabolites pathways in in vitro systems of P. solmsianum