Search results for "BAC"
showing 10 items of 10211 documents
Conjugation is necessary for a bacterial plasmid to survive under protozoan predation
2016
Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogenSerratia marcescens. A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of con…
Recent advancements in lactic acid production - a review.
2017
Abstract Lactic acid, as an organic acid, has essential roles in industrial applications ranging from the food industry to life-sciences. Conventional fermentation methods have been well-studied since late 18th century, but are unable to achieve consumers' expectations regarding both quality and quantity. Therefore, novel technological developments of lactic acid production to increase yield and decrease over-all cost have become the primary goal. Genetic and metabolic engineering are great tools to overcome problems associated with product inhibition, undesired by-product formation, the negative effect of extreme culture conditions and most importantly inefficient use of expensive substrat…
Investment in multiple defences protects a nematode-bacterium symbiosis from predation
2017
The act of predation often comprises multiple sequential steps whereby prey can employ defences at all or some of these stages to deter predation. However, investment in defences is costly unless they are outweighed by conferring some benefit to the bearer. One system that employs multiple defences is that of the entomopathogenic nematode Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus luminescens. This nematodeebacterium complex infects and kills soil-dwelling insect larvae, in which they then reproduce and juveniles emerge 2 weeks later. Predation of the infected host cadaver at any point during infection is fatal for the parasitic colony inside. Infected individual…
The aminophosphonate glyphosine enhances phycobiliprotein yields from selected cyanobacterial cultures
2017
Among added-value products obtained from cyanobacterial cultures are phycobiliproteins, photosynthetic pigments that have found an increasing number of applications as natural dyes for food, cosmetics, pharmaceuticals, and antioxidants. To obtain sustainable production, we aimed at maximizing phycobilin yield through the increase of either the final biomass or the specific content of these pigments by varying culture parameters, such as chemical composition and pH of the medium or quality and intensity of the light. Here, we report that the addition to the culture medium of millimolar or submillimolar concentrations of the aminophosphonate glyphosine [(N,N-bis(phosphonomethyl)glycine], form…
Colorado potato beetle chymotrypsin genes are differentially regulated in larval midgut in response to the plant defense inducer hexanoic acid or the…
2019
When Colorado potato beetle larvae ingested potato plants treated with the plant defense inducer compound hexanoic acid, midgut chymotrypsin enzyme activity increased, and the corresponding chymotrypsin genes were differentially expressed, evidence of the larval digestive proteolytic system's plasticity. We previously reported increased susceptibility to Cry3Aa toxin in larvae fed hexanoic acid treated plants. Here we show that the most expressed chymotrypsin gene in larvae fed hexanoic acid treated plants, CTR6, was dramatically downregulated in Cry3Aa intoxicated larvae. lde-miR-965-5p and lde-miR-9a-5p microRNAs, predicted to target CTR6, might be involved in regulating the response to h…
Selective sweep ofWolbachiaand parthenogenetic host genomes - the example of the weevilEusomus ovulum
2016
Most parthenogenetic weevil species are postulated to have originated via hybridization, but Wolbachia has also been speculated to play a role via the induction of parthenogenesis. Here, we examine the molecular diversity of Wolbachia and parthenogenetic host genomes. The host species studied here, Eusomus ovulum, is known to be exclusively parthenogenetic and triploid. The E. ovulum populations that we examined had a low genetic diversity of mitochondrial (cytochrome oxidase I gene) and nuclear markers (internal transcribed spacer 2 and elongation factor 1-α gene), and they all were infected by only single bacteria strains (genotyped for five genes according to the multilocus sequence typi…
Application of high resolution melting assay (HRM) to study temperature-dependent intraspecific competition in a pathogenic bacterium
2017
AbstractStudies on species’ responses to climate change have focused largely on the direct effect of abiotic factors and in particular temperature, neglecting the effects of biotic interactions in determining the outcome of climate change projections. Many microbes rely on strong interference competition; hence the fitness of many pathogenic bacteria could be a function of both their growth properties and intraspecific competition. However, due to technical challenges in distinguishing and tracking individual strains, experimental evidence on intraspecific competition has been limited so far. Here, we developed a robust application of the high-resolution melting (HRM) assay to study head-to…
Multi-modal defences in aphids offer redundant protection and increased costs likely impeding a protective mutualism.
2017
The pea aphid, Acyrthosiphon pisum, maintains extreme variation in resistance to its most common parasitoid wasp enemy, Aphidius ervi, which is sourced from two known mechanisms: protective bacterial symbionts, most commonly Hamiltonella defensa, or endogenously encoded defences. We have recently found that individual aphids may employ each defence individually, occasionally both defences together, or neither. In field populations, Hamiltonella-infected aphids are found at low to moderate frequencies and while less is known about the frequency of resistant genotypes, they show up less often than susceptible genotypes in field collections. To better understand these patterns, we sought to co…
Genetic diversity in a collection of Italian long storage tomato landraces as revealed by SNP markers array
2019
Tomato (Solanum lycopersicum L.) is one of the most important crops worldwide. In this study, we used 7720 genome-wide SNPs to characterize the genetic diversity within a tomato germplasm collection enriched with 64 accessions from southern Italy of the so called "da serbo" type i.e. drought-tolerant and long storage landraces. Notwithstanding the relatively small collection area, 1575 (20.4%) polymorphic SNPs, mostly on Chr11, detected considerable levels of genetic variation. Maximum parsimony analysis of genetic distance revealed four main clusters and clearly separated most "da serbo" landraces from the outgroups. One of the clusters grouped the landraces from the Mount Vesuvius area, t…
Acceptor Specificity of Amylosucrase from Deinococcus radiopugnans and Its Application for Synthesis of Rutin Derivatives
2016
The transglycosylation activity of amylosucrase (ASase) has received significant attention owing to its use of an inexpensive donor, sucrose, and broad acceptor specificity, including glycone and aglycone compounds. The transglycosylation reaction of recombinant ASase from Deinococcus radiopugnans (DRpAS) was investigated using various phenolic compounds, and quercetin-3-O-rutinoside (rutin) was found to be the most suitable acceptor molecule used by DRpAS. Two amino acid residues in DRpAS variants (DRpAS Q299K and DRpAS Q299R), assumed to be involved in acceptor binding, were constructed by site-directed mutagenesis. Intriguingly, DRpAS Q299K and DRpAS Q299R produced 10-fold and 4-fold hig…