Generation of highly selective monoclonal antibodies inhibiting a recalcitrant protease using decoy designs

Matrix metalloproteinase-12 (MMP-12), also known as macrophage elastase, is a potent inflammatory mediator and therefore an important pharmacological target. Clinical trial failures of broad-spectrum compound MMP inhibitors suggested that specificity is the key for a successful therapy. To provide the required selectivity, monoclonal antibody (mAb)-based inhibitors are on the rise. However, poor production of active recombinant human MMP-12 catalytic domain (cdMMP-12) presented a technical hurdle for its inhibitory mAb development. We hypothesized that this problem could be solved by designing an expression-optimized cdMMP-12 mutant without structural disruptions at its reaction cleft and surrounding area, and thus isolated active-site inhibitory mAbs could maintain their binding and inhibition functions toward wild-type MMP-12. We combined three advances in the field—PROSS algorithm for cdMMP-12 mutant design, convex paratope antibody library construction, and functional selection for inhibitory mAbs. As a result, isolated Fab inhibitors showed nanomolar affinity and potency toward cdMMP-12 with high selectivity and high proteolytic stability. Particularly, Fab LH11 targeted the reaction cleft of wild-type cdMMP-12 with 75 nM binding K_D and 23 nM inhibition IC₅₀. We expect that our methods can promote the development of mAbs inhibiting important proteases, many of which are recalcitrant to functional production.     

The Response of Triticum aestivum Treated with Plant Growth Regulators to Acute Day/Night Temperature Rise

The fluctuation in temperature adversely affects grain development when the climate changes intermittently. This study investigated the effect of high day/night temperatures (34/30 °C, 38/34 °C and 42/38 °C) for two stress durations (24 h and 48 h) on Triticum aestivum. To ascertain the role of plant growth regulator (PGR) in alleviating the deleterious effects of high temperature stress, the combination of various PGRs (e.g., methyl jasmonate, salicylic acid, ascorbic acid, calcium chloride and indole acetic acid) were foliar sprayed twice; one week prior to commencement of anthesis stage and immediately after the exposure to high temperature stress. In general, the high temperature reduces plant growth, grain setting, and 100-grain weight. High temperature stress causes deterioration of plant photosynthetic machinery through a significant decline in energy dissipation, linear electron flow (LEF) and quantum yield of photosystem II (Phi2) which led to plant death. An increase in the antioxidant enzymes activity (SOD, APX, and CAT) was observed at 38/34 °C, while their activity declined sharply at 42/38 °C. Grain setting and filling were completely inhibited in plants exposed to 42/38 °C even when treated with different combinations of PGRs. Salicylic acid along with methyl jasmonate was the most effective PGR combination resulting in significant improvements in Phi2, NPQt, SOD, grain filling and grain protein content under high temperature stress. A strong correlation was observed between LEF and chlorophyll contents against the number of grains per spike and 100-grain weight. In summary, acute day and night temperature stress adversely affected wheat morphological, physiological, and yield traits, while foliar application of PGRs was partially effective in mitigating these harmful changes.

     

Isatin-derived Antibacterial and Antifungal Compounds and their Transition Metal Complexes

A series of isatins incorporating thiazole, thiadiazole, benzothiazole and p-toluene sulfonyl hydrazide moieties, along with their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by elemental analyses, molar conductances, magnetic moments, IR, NMR and electronic spectral data. These compounds have been screened for antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi, and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata using the agar-well diffusion method. All the synthesized compounds have shown good affinity as antibacterial and/or antifungal agents which increased in most of the cases on complexation with the metal ions.     

Overcoming biochemical pharmacologic mechanisms of platinum resistance with a texaphyrin-platinum conjugate

In our effort to investigate further texaphyrin conjugation as a means of increasing delivery and accumulation of known anticancer platinum agents in cancer cells, we have continued our studies on the mode of action of a texaphyrin-platinum conjugate, particularly in cisplatin-resistant tumor cells that are characterized by several mechanisms of resistance, including reduced drug accumulation. Our results provide support for the proposal that intracellular platinum and Pt-DNA adduct levels were significantly increased using our conjugate relative to corresponding Pt controls. Moreover, no differences were found in cellular accumulation and Pt-DNA adduct formation between Pt sensitive and Pt resistant ovarian cells. As a result, resistance to the conjugate was lower than cisplatin in resistant cells. Based on these results we conclude that texaphyrin conjugation provides a promising strategy for overcoming biochemical pharmacologic mechanisms of resistance.     

The role of plant-associated rhizobacteria in plant growth,biocontrol and abiotic stress management

The rhizosphere is the region around the plant roots where maximum microbial activities occur. In the rhizosphere, microorganisms' beneficial and harmful activities affect plant growth and development. The mutualistic rhizospheric bacteria which improve plant growth and health are known as plant growth-promoting rhizobacteria (PGPR). They are very important due to their ability to help the plant in diverse ways. PGPR such as Pseudomonas, Bacillus, Azospirillum, Azotobacter, Arthrobacter, Achromobacter, Micrococcus, Enterobacter, Rhizobium, Agrobacterium, Pantoea and Serratia are now very well known. Rhizomicrobiome plays critical roles in nutrient acquisition and assimilation, improved soil texture, secreting and modulating extracellular molecules such as hormones, secondary metabolites, antibiotics and various signal compounds, all leading to the enhancement of plant growth and development. The microbes and compounds they secrete constitute valuable biostimulants and play pivotal roles in modulating plant stress responses. In this review, we highlight the rhizobacteria diversity and cutting-edge findings focusing on the role of a PGPR in plant growth and development. We also discussed the role of PGPR in resisting the adverse effects arising from various abiotic (drought, salinity, heat, heavy metals) stresses.     

Phytochemical,antioxidant and mineral composition of hydroalcoholic extract of chicory (Cichorium intybus L.) leaves

The phytochemical, antioxidant and mineral composition of hydroalcoholic extract of leaves of Cichorium intybus L., was determined. The leaves were found to possess comparatively higher values of total flavonoids, total phenolic acids. The phytochemical screening confirmed the presence of tannins, saponins, flavonoids, in the leaves of the plant. The leaf extract was found to show comparatively low value of IC₅₀ for 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition. The IC₅₀ value of chicory leaves extract was found to be 67.2 ± 2.6 μg/ml. The extracts were found to contain high amount of mineral elements especially Mg and Zn. Due to good phytochemical and antioxidant composition, C. intybus L., leaves would be an important candidate in pharmaceutical formulations and play an important role in improving the human health by participating in the antioxidant defense system against free radical generation.