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Sheath blight incited by Rhizoctonia solani is an important rice disease that constitutes a major challenge to rice production worldwide. Nematode-trapping fungi possess the ability to capture, kill and digest the nematodes. However, the ability of many nematode-trapping fungi parasitizing the soil borne plant pathogens may fillip the gap towards maximum exploitation of these fungi in biological control strategy. In present study, we have investigated the mycoparasitc potential of Arthobotrys conoides, A. eudermata, Dactylellina gephyropaga and D. phymatopaga against Rhizoctonia solani in in vitro and rice plants grown under green house conditions. We found that Arthobotrys conoides, A. eudermata and Dactylellina gephyropaga started forming coils around hyphae of Rhizoctonia solani within 24 h of hyphal interaction. A. eudermata was found highly mycoparasitic on all isolates of R. solani followed by A. conoides and D. gephyropaga. Dactylellina phymatopaga failed to parasitize any isolates of R. solani. At the site of coiling, a strong cell wall proliferation was observed in Rhizoctonia cells and the cytoplasm of these cells subsequently disintegrated. Treatment of R. solani infested soils with colony forming units of A. eudermata, A. conoides and D. gephyropaga decreased sheath blight infection in rice tillers by 43.39–50.74% as compared to non-treated but R. solani inoculated plants.

Intertidal marine brown alga Turbinaria conoides (J.Agardh) Kutzing (family Sargassaceae) is considered as one of the largely abundant species, available in the coastal zones of the Indian subcontinent. Bioactivity-guided chromatographic fractionation of the organic extract of T. conoides resulted in three previously undescribed macrocyclic lactone homologues, named as conoidecyclics A-C. Conoidecyclic A displayed greater attenuation potential against cyclooxygenase-2 (IC50 1.75 mM) and 5-lipoxygenase (IC50 4.24 mM) in comparison with other analogues. Conoidecyclic A exhibited higher attenuation potential against 5-lipoxygenase than that displayed by an anti-inflammatory agent, ibuprofen (IC50 4.51 mM). The higher selectivity index of conoidecyclic A (1.79) recognized its selective attenuation potential against the inducible cyclooxygenase-2 enzyme. Inhibition potential of conoidecyclic A against angiotensin converting enzyme-I (IC50 1.23 mM) and protein tyrosine phosphatase-1B (IC50 1.39 mM) were non-competitive, as deduced by kinetic studies. In-silico molecular modeling study of conoidecyclic A with the allosteric sites of the targeted enzymes exhibited least binding energy of −14.51 to −11.27 kcal mol−1 compared to those exhibited by other studied macrolide homologues. Reaction kinetic studies of conoidecyclic A coupled with lesser apparent Vmax inferred that it could efficiently bind with the allosteric site of targeted enzymes in a non-competitive manner to diminish the reaction velocity resulting in enzyme inhibition. Drug-likeness and predictive pharmacokinetic parameters of conoidecyclic A exhibited an acceptable oral bioavailability. These reports inferred that conoidecyclic A encompassing pentacosa macrocyclic moiety could be a promising therapeutic lead to inhibit the enzymes related to the development and progression of pathological conditions leading to inflammation, hypertension and type-2 diabetes.

Four tropical seaweeds, Gracilaria manilaensis Yamamoto & Trono, Ulva reticulata Forsskål, Kappaphycus alvarezii (Doty) L.M.Liao and Turbinaria conoides (J.Agardh) Kützing, collected from various habitats throughout Malaysia, were subjected to temperatures of 40, 35, 30, 25 and 20 ◦C in the laboratory. An exposure range of 21–38 ◦C is reported for Malaysian waters. The effect of the temperature exposures on the halocarbon emissions of the seaweeds were determined 4 and 28 h after treatment. The emission rates for a suite of six halocarbons commonly emitted by seaweeds, bromoform (CHBr3), dibromomethane (CH2Br2), diiodomethane (CH2I2), iodomethane (CH3I), dibromochloromethane (CHBr2Cl) and dichlorobromomethane (CHBrCl2), were measured using a cryogenic purge-and-trap sample preparation system coupled to a gas chromatography–mass spectrometry. The emission rate of CHBr3 was the highest of the six halocarbons for all the seaweeds under all the temperatures tested, followed by CH2Br2, and CH2I2. The emission rates were affected by temperature change and exposure duration, but overall responses were unique to each seaweed species. Larger decreases in the emissions of CHBr3, CH2Br2, CH2I2 and CHBr2Cl were found for K. alvarezii and T. conoides after 4 h at 40 ◦C. In both cases there was a >90% (p < 0.05) reduction in the Fv/Fm value suggesting that photosynthetic actitivity was severely compromised. After a 28 h exposure period, strong negative correlations (r = -0.69 to -0.95; p < 0.01) were observed between temperature and the emission of CHBr3, CH2Br2 and CH2I2 for U. reticulata, K. alvarezii and T. conoides. This suggests a potential decrease in the halocarbon emissions from these tropical seaweeds, especially where the temperature increase is a prolonged event. Strong correlations were also seen between seaweed chlorophyll and carotenoid pigment contents and the emission rates for CHBr3, CH2Br2 and CH2I2 (r = 0.48 to 0.96 and -0.49 to -0.96; p < 0.05). These results suggest that the regulation of halocarbon production versus reactive oxygen species production in seaweeds is an area worthy of further exploration.

The aim of the present investigation was to study the potential of two brown seaweeds ( Sargassum wightii and Turbinaria conoides ) to remove praseodymium ions from solutions. Due to swelling problems, the seaweed biomasses were also immobilized using polysulfone matrices which amplified hydraulic conductivity more than 7.1 times. At optimum pH of 5, maximum Pr(III) uptakes of 131.4, 146.4, 111.2 and 119.5 mg/g were observed for free- S. wightii , free- T. conoides , polysulfone immobilized S. wightii (PISW) and polysulfone immobilized T. conoides (PITC), respectively. Experimental biosorption isotherms were successfully described using the Langmuir, Freundlich and Sips model. Owing to intraparticle diffusion, rate of Pr(III) sorption by immobilized biosorbents was slow and equilibrium attainment took 240 min compared to only 90 min by free biomasses. However, regeneration of seaweed biomasses for repeated sorption application was only possible with immobilization biosorbents. With 0.1 mol/L HCl as elutant, both PITC and PISW exhibited invariable Pr(III) uptake capacity and very high mechanical stability over 10 sorption-desorption cycles.

Objective To evaluate the antifungal activity of seaweed extracts against human fungal pathogens. Methods Antifungal activity of six species of marine macro algae Codium decorticatum, Caulerpa scalpelliformis, Gracilaria crassa, Acanthophora spicifera, Sargassum wightii and Turbinaria conoides using different solvents acetone, methanol, chloroform, diethyl ether, ethyl acetate, hexane and aqueous were evaluated against Fusarium oxysporum, Fusarium udum, Fusarium solani, Rhizoctonia solani, Alternaria alternat, Botrytis cinerea, Candida albicans, Candida krusei, Aspergillus niger and Aspergillus flavus. Results From the investigation, the maximum activity was recorded from Phaeophyceae, Chlorophyceae and Rhodophyceae respectively. The maximum inhibition zone was noted in acetone extract of T. conoides against F. udum . Conclusions From these findings, it is concluded that brown seaweed Turbinaria conoides is more effective than the green and red seaweeds.

In the present study, the potential of a new brown marine alga, Turbinaria conoides , in biosorption and subsequent bioreduction of Au(III) was explored. The biosorption process was found to be rapid and completed within 60 min of contact. Also, the solution pH strongly affected Au(III) biosorption by T. conoides , with maximum uptake of 34.5 mg/g being observed at pH 2 according to the Langmuir model. Biosorption mechanism was proposed to involve electrostatic interactions between gold anions and algal functional groups, which implies that when virgin T. conoides was exposed to gold solution, AuCl 4 − anion binds to positively charged functional groups, such as amino groups (NH 2 ), on the algal surface. After 60 min, T. conoides reduced Au(III) to gold nanoparticles. Hydroxyl groups present in the brown algal polysaccharides were involved in the bioreduction of Au(III) to Au(0). The field emission scanning electron micrographs showed uniformly scattered nanoparticles with sporadic aggregation on the surface of T. conoides . XRD diffraction patterns of gold-loaded T. conoides also confirmed that the Au(III) bound on the cell wall of the biomass had been reduced to Au(0). The UV–vis spectra results indicated that the reaction solution had an absorption maximum at about 540 nm attributable to the surface plasmon resonance band of the gold nanoparticles.

In vitro antioxidant activities of three selected Indian brown seaweeds – viz., Sargassum marginatum, Padina tetrastomatica and Turbinaria conoides – were investigated. Total phenolic content and reducing power of crude methanolic extract were also investigated. The activity of total methanolic extract and five different fractions (viz., petroleum ether (PE), ethyl acetate (EA), dichloromethane (DCM), butanol (BuOH) and aqueous) were studied using total antioxidant activity, DPPH radical scavenging and deoxyribose assays. EA fraction of S. marginatum exhibited higher total antioxidant activity of 39.62 mg ascorbic acid equivalent/g extract (or 0.31 mg ascorbic acid equivalent/g seaweed on dry weight basis) among the all the fractions. Among the fractions obtained from different seaweeds, EA fraction of S. marginatum showed higher DPPH scavenging activity of 23.16%; while PE fraction of T. conoides exhibited lower deoxyribose activity of 47.81%. Higher phenolic content (49.16 mg gallic acid equivalent/g extract or 0.86 mg GAE/g of seaweed on dry weight basis) was noticed in aqueous fraction of T. conoides. Reducing power of crude methanolic extract increased with increasing concentration. Reducing power of T. conoides and P. tetrastomatica were higher compared to standard antioxidant (α-tocopherol). Among the seaweeds, total methanolic extract of T. conoides had significantly higher phenol content (P

Spore germination of net-producing nematophagous fungi can lead to either immediate formation of the trap or, more usually, the production of a single hypha upon which nets are eventually produced. However, in isolates of Arthrobotrys conoides and A. cladodes, spores on blocks of water agar were observed to germinate and fuse readily with adjacent spores or vegetative hyphae. Where spores of A. conoides had fused with each other, usually only a single hypha grew from them, indicating that this may provide more nutrient for the developing hypha. Alternatively, fusion of spores may merely reflect the tendency of hyphae of these fungi to anastomose.

Summary Lipids, cholesterol and activity of certain key enzymes involved in the biosynthesis of steroids, viz., steroid dehydrogenases, reduced nicotinamide adenine dinucleotide (NADH) diaphorase and glucose-6-phosphate dehydrogenase (G-6-PDH) have been studied by means of cytochemical methods in different stages of the life-cycle of the gregarine Stylocephalus conoides . All the aforesaid precursors and the enzymes have been detected in the trophozoite of this gregarine indicating the organism's steroidogenic potential.