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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Molecular characterization of Cryptococcus neoformans and Cryptococcus gattii from environmental sources and genetic comparison with clinical isolates in Apulia, Italy

Highlights: • Meta-analysis of data recorded during environmental surveys of Cryptococcus spp in Apulia. • Olive trees can be an alternative ecological niche for C. neoformans and C. gattii. • Correlation clinical cases with possible new environmental sources of infection. The present study investigated the environmental distribution of Cryptococcus neoformans and C. gattii species complex molecular types, mating types and sequence types in Apulia, a region of Southern Italy. A total of 2078 specimens from arboreal and animal sources were analyzed. The percentage of positive samples was similar among both arboreal and animal specimens: 4.2% vs. 5.1% for C. neoformans species complex and 0.6% vs. 1.4% for C. gattii species complex. Molecular typing identified 78 isolates as VNI (76 αA and two aA), one as AD-hybrid αADa, and 16 as VGI aB. VNI isolates presented 10 different sequence types (STs) and VGI isolates two. The most frequent STs among C. neoformans and C. gattii species complex isolates were ST23 (51%) and ST156 (90%), respectively. Comparison with molecular types and STs results obtained from 21 clinical isolates collected in Apulia showed that one C. neoformans VNI clinical isolate shared an identical sequence type of one arboreal isolate (ST61) and that one C. gattii VGI clinical isolate matched with the main ST (ST156) present in the environment. In addition, molecular type VNIV was found only among clinical isolates and was absent in the investigated environmental area. In conclusion, the present study identified which C. neoformans and C. gattii species complex genotypes are circulating in Apulia, defined their ecological niches and revealed the relationship with clinical cases. It represents a basal study for addressing future investigations and public health interventions in the region.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Enhancing molecular design efficiency: Uniting language models and generative networks with genetic algorithms

This study examines the effectiveness of generative models in drug discovery, material science, and polymer science, aiming to overcome constraints associated with traditional inverse design methods relying on heuristic rules. Generative models generate synthetic data resembling real data, enabling deep learning model training without extensive labeled datasets. They prove valuable in creating virtual libraries of molecules for material science and facilitating drug discovery by generating molecules with specific properties. While generative adversarial networks (GANs) are explored for these purposes, mode collapse restricts their efficacy, limiting novel structure variability. To address this, we introduce a masked language model (LM) inspired by natural language processing. Although LMs alone can have inherent limitations, we propose a hybrid architecture combining LMs and GANs to efficiently generate new molecules, demonstrating superior performance over standalone masked LMs, particularly for smaller population sizes. This hybrid LM-GAN architecture enhances efficiency in optimizing properties and generating novel samples.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Genetic diversity within the botulinum neurotoxin-producing bacteria and their neurotoxins

The recent availability of multiple Clostridium botulinum genomic sequences has initiated a new genomics era that strengthens our understanding of the bacterial species that produce botulinum neurotoxins (BoNTs). Analysis of the genomes has reinforced the historical Group I–VI designations and provided evidence that the bont genes can be located within the chromosome, phage or plasmids. The sequences provide the opportunity to examine closely the variation among the toxin genes, the composition and organization of the toxin complex, the regions flanking the toxin complex and the location of the toxin within different bacterial strains. These comparisons provide evidence of horizontal gene transfer and site-specific insertion and recombination events that have contributed to the variation observed among the neurotoxins. In this work, examples that have contributed to the variation observed in serotypes A-H strains are presented to illustrate the mechanisms that have contributed to their variation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2012

Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

60 APPLIED LIFE SCIENCES↗