SORPTION OF HEAVY METALS BY MOLD FUNGUS ASPERGILLUS CARBONARIUS MELANIZING CARDBOARD

It has been shown that the mould fungus Aspergillus carbonarius, which synthesizes extracellular melanin, is able to develop due to the degradation of cellulose inside the cardboard under conditions of low water availability. The maximum yield of melanin was noted in a slightly alkaline medium, but in the presence of copper ions, a high level of pigmentation of the medium is also observed at low pH values. Melanized mycelium and exomelanin are characterized by a high sorption capacity in relation to heavy metal ions present in printing pigments of waste paper. In the process of growth A. carbonarius decreases acidity from neutral values to pH 2.8–3.1, increases the mobility of heavy metals immobilized on cellulose fibers and binds them by functional groups via ionic or chelating pathways. The sorption capacity of biomass with respect to copper, zinc, and nickel ions increased in the order of viable mycelium < inactivated mycelium < exomelanin. Lead ions were most actively bound by inactivated mycelium. The extracellular pigment accumulated copper better than other metals. The distribution coefficient in the system melanin – Cu2+ reached 1390 ml/g.

Biosynthesis of Silver Nanoparticles Mediated by Extracellular Pigment from Talaromyces purpurogenus and Their Biomedical Applications

In recent years, green syntheses have been researched comprehensively to develop inexpensive and eco-friendly approaches for the generation of nanoparticles. In this context, plant and microbial sources are being examined to discover potential reducing agents. This study aims to utilize an extracellular pigment produced by Talaromyces purpurogenus as a prospective reducing agent to synthesize silver nanoparticles (AgNPs). Biosynthesized AgNPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), electron probe micro analyser (EPMA), and zeta potential. The pigment functional groups involved in the generation of AgNPs were investigated using Fourier transform infrared spectroscopy. TEM images showed that the generated nanoparticles were spherical, hexagonal, rod-shaped, and triangular-shaped with a particle size distribution from 4 to 41 nm and exhibited a surface plasmon resonance at around 410 nm. DLS and zeta potential studies revealed that the particles were polydispersed and stable (−24.8 mV). EPMA confirmed the presence of elemental silver in the samples. Biosynthesized AgNPs exhibited minimum inhibitory concentrations of 32 and 4 μg/mL against E. coli and S. epidermidis, respectively. Further, cytotoxicity of the AgNPs was investigated against human cervical cancer (HeLa), human liver cancer (HepG2), and human embryonic kidney (HEK-293) cell lines using 5-fluorouracil as a positive control. A significant activity was recorded against HepG2 cell line with a half-maximal inhibitory concentration of 11.1 μg/mL.

Effect of amino acids on pigments, citrinin, and lovastatin production by Monascus purpureus under static conditions

Monascus spp. is known to produce many secondary metabolites including pigments, statin, and undesired mycotoxin. M. purpureus MTCC 410 strain was grown statically for ten days in potato dextrose broth supplemented with 1% UV sterilized amino acids. Whatmann filter No. 1 was used to separate the developed mycelia from the broth to get the intracellular pigment as the extracellular one is left in the filtrate. The pigment concentration was estimated by the calorimetric method for different wavelengths and expressed in colour value units (CVU). The presence of citrinin in the growth medium was checked under UV light at 350 nm and quantification was done with highperformance liquid chromatography column along with loop injector of 20 μl, and Shimadzu CLASS-VP version 5.032 software. The maximum biomass (143.6 g/l) was observed with supplementation of 1% D-serine to the medium, whereas the maximum intracellular pigment yield was observed with supplementation of L-histidine monohydrochoride (yellow – 4.48, orange – 3.97 and red pigment – 2.0 CVU/ml). The maximum extracellular pigment yield was observed with supplementation of glycine (yellow – 2.18, orange – 1.65 and red pigment – 1.38 CVU/ml to the growth medium). The maximum lovastatin yield was observed with supplementation of L-cysteine mono hydrochloride and concentration of 2064 mg/l. Maximum citrinin (1.29 mg/l) was observed with supplementation of DL-norleucine to the growht medium. M. purpureus requires suitable concentration of organic nitrogen in the form of amino acids for a higher yield of secondary metabolites such as supplementation of 1% L-cysteine monohydrochloride or L-tyrosine in the growth medium under submerged cultivation. None of the tested amino acids produced citrinin under experimental conditions making the outcome beneficial for industrial purposes.

Antitubercular activity of the pigment from forest soil Streptomyces sp SFA5

<p class="Abstract">Extracellular pigment from the forest soil <em>Streptomyces</em> sp SFA5 was produced by submerged fermentation using yeast extract malt extract broth. Crude pigment from the medium was extracted using ethyl acetate. Antitubercular activity of the pigment was tested against <em>M. tuberculosis</em> H37Rv by microplate alamar blue assay and luciferase reporter phage assay. The pigment was also tested for inhibitory activity against <em>M. tuberculosis</em> lysine aminotransferase by colorimetric method. In both microplate alamar blue and luciferase reporter phage assay, the crude pigment showed activity against <em>M. tuberculosis</em> H37Rv at 125 and 250 µg/mL concentration, respectively. The <em>M. tuberculosis</em> lysine aminotransferase was inhibited at the IC₅₀ value of 4.5 µg/mL concentration.</p><p> </p>

Ultrastructural Changes in Human Trabecular Meshwork Tissue after Laser Trabeculoplasty

Purpose. To compare morphologic changes in human trabecular meshwork (TM) after selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT).Design. Laboratory evaluation of ex vivo human eye TM after laser trabeculoplasty.Methods. Corneoscleral rims from human cadaver eyes were sectioned and treated with varying powers of either SLT or ALT. Specimens were examined using light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).Results. TEM of SLT at all powers resulted in disrupted TM cells with cracked and extracellular pigment granules. SEM of SLT samples treated at high power revealed tissue destruction with scrolling of trabecular beams. SEM of ALT-treated tissue showed increasing destruction with exposure to higher power. The presence or absence of “champagne” bubbles during SLT did not alter the histologic findings.Conclusions. SLT-treated human TM revealed disruption of TM cells with cracked, extracellular pigment granules, particularly at higher treatment powers. Tissue scrolling was noted at very high SLT energy levels. ALT-treated tissue showed significant damage to both the superficial and deeper TM tissues in a dose-dependent fashion. Further studies are needed to guide titration of treatment power to maximize the IOP-lowering effect while minimizing both energy delivered and damage to target tissues.

Genetic diversity among Curtobacterium flaccumfaciens pv. flaccumfaciens populations in the American High Plains

Curtobacterium flaccumfaciens pv. flaccumfaciens is a Gram-positive bacterium and has reemerged as an incitant of bacterial wilt in common (dry, edible) beans in western Nebraska, eastern Colorado, and southeastern Wyoming. Curtobacterium flaccumfaciens pv. flaccumfaciens is diverse phenotypically and genotypically and is represented by several different pathogen color variants. The population structure of 67 strains collected between 1957 and 2009, including some isolated from alternate hosts, was determined with 3 molecular typing techniques: amplified fragment length polymorphism (AFLP), repetitive extragenic palindromic polymerase chain reaction (rep-PCR), and pulsed-field gel electrophoresis (PFGE). All 3 typing techniques showed a great degree of population heterogeneity, but they were not congruent in cluster analysis of the C. flaccumfaciens pv. flaccumfaciens populations. Cluster analysis of a composite data set (AFLP, PFGE, and rep-PCR) using averages from all experiments yielded 2 distinct groups: cluster A included strains with colonies of yellow, orange, and pink pigments, and cluster B had strains of only yellow pigment. Strains producing purple extracellular pigment were assigned to both clusters. Thus, C. flaccumfaciens pv. flaccumfaciens is diverse phenotypically and genotypically.