Interaction of TiO2 nanoparticles with soil: Effect on microbiological and chemical traits.

Titanium dioxide (TiO2) nanoparticles (NPs) are the most widely used nanomaterials and their expanding use raises concerns about their impacts on soil ecosystems and functioning. The present study evaluates the potential impacts of TiO2 NPs applied at low doses (0, 1.0, 2.5, 5.0, 10.0 and 20.0 mg L-1) on soil chemical properties including the macro and micronutrient contents, microbial population and enzyme activities in rhizosphere soil of mung bean crop at different time intervals (7, 14, 28 and 56 days). A quantitative RT-PCR study was also performed to study the relative change in the gene expression of ammonia oxidizer and nitrogen fixers upon TiO2 NP supplementation. An increase in soil nutrient content viz., available N, P, Cu, Fe, Mn, nitrate-N and ammonical-N was observed with NP application except available K and Zn content. The TiO2 NPs stimulated the growth of soil microflora at low concentrations while an inhibitory effect was recorded at high concentrations. The soil fungi and actinobacteria emerged as the most sensitive groups of soil microbes towards TiO2 NP exposure exhibiting detrimental impacts on their growth at all concentrations. Similarly, the soil enzyme activities enhanced till TiO2 NPs (10.0 mg L-1) which was followed by decrease at higher concentrations. The qRT-PCR study showed that the ammonia oxidizers were more affected by TiO2 NPs application than nitrogen fixers. These findings suggest that TiO2 NPs can be used as stimulators of soil nutrients and soil microbial dynamics at low concentrations.

Neonatal Acute Liver Failure Associated with Angioinvasive Hepatic Zygomycosis.

BACKGROUND: Neonatal acute liver failure (NALF) is often a fatal condition. Zygomycosis is a fungal infection that is often fatal in both adults and infants. Only a few cases of hepatic zygomycosis are reported in the literature and they are invariably associated with immunosuppression. MATERIALS AND METHODS: Post-mortem liver biopsy from a 14-day old neonate demonstrated confluent panacinar necrosis with angioinvasive zygomycosis. The limited work-up could not rule out an underlying immunodeficiency. CONCLUSION: Angioinvasive hepatic zygomycosis can present in the neonatal period as NALF.

Microbacterium aureliae sp. nov., a novel actinobacterium isolated from Aurelia aurita, the moon jellyfish.

The taxonomic position of a lemon-yellow-pigmented actinobacterium, strain JF-6T, isolated from Aurelia aurita, the moon jellyfish, collected from the Bay of Bengal coast, Kanyakumari, India, was determined using a polyphasic approach. The strain had phenotypic and chemotaxonomic properties that were consistent with its classification in the genus Microbacterium. Alignment of the 16S rRNA gene sequence of strain JF-6T with sequences from Microbacterium arthrosphaerae CC-VM-YT, Microbacterium yannicii G72T, Microbacterium trichothecenolyticum IFO 15077T, Microbacterium flavescens DSM 20643T, Microbacterium insulae DS-66T, Microbacterium resistens DMMZ 1710T and Microbacterium thalassium IFO 16060T revealed similarities of 98.95, 98.76, 98.43, 98.41, 98.41, 98.26 and 98.22 %, respectively. However, the levels of DNA-DNA relatedness with its closest phylogenetic neighbours confirmed that it represents a novel species within the genus. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and an unknown glycolipid. The major menaquinones detected for strain JF-6T were MK-13 and MK-12. The diamino acid in the cell-wall peptidoglycan was ornithine and the peptidoglycan was type B2ß (Glu/Hyg-Gly-d-Orn). The DNA G+C content was 69.4 mol%. Based on these differences, strain JF-6T (=MTCC 11843T=JCM 30060T=KCTC 39828T) should be classified as the type strain of a novel species of Microbacterium, for which the name Microbacterium aureliae sp. nov. is proposed.