Search results for "Biochemical Phenomena"

Vibrio vulnificus produces quorum sensing signals of the AHL-class

2009

Vibrio vulnificus is an aquatic pathogenic bacterium that can cause vibriosis in humans and fish. The species is subdivided into three biotypes with the fish-virulent strains belonging to biotype 2. The quorum sensing (QS) phenomenon mediated by furanosyl borate diester or autoinducer 2 (AI-2) has been described in human strains of biotype 1, and here we show that the luxS gene which encodes AI-2 is present in all strains of V. vulnificus regardless of origin, biotype or serovar. In this study, we also demonstrate that V. vulnificus produces QS signals of the acylated homoserine lactone (AHL) class (AI-1). AHLs were detected in strains of biotype 1 and 2 from water, fish and human wound inf…

2020

Objective: The suggested link between major depression disorder (MDD) and blood–brain barrier (BBB) alterations supports an impact on the neurovascular unit in this disease condition. Here we inves...

Gibberellic acid stimulates lipid metabolism in barley aleurone protoplasts

1991

Abstract Changes in the lipid composition of barley aleurone protoplasts following incubation in the presence or absence of gibberellic acid (GA) were studied and correlated with cell development. Analysis of neutral lipids in protoplast extracts and purified lipid bodies provide evidence for the strong effect of GA on the mobilization of storage lipids. In vivo protoplast staining with the membrane marker N -phenyl-l-naphthylamine (NPN) and phospholipid determinations of protoplast extracts show an increase in membrane lipids during protoplast incubation. GA stimulates phospholipid metabolism by increasing the synthesis of phosphatidyl ethanolamine and phosphatidyl choline, the major phosp…

Effects of Ga3 and Ca2+ on barley aleurone protoplasts: a freeze-fracture study

1988

Freeze-fracture electron microscopy was used to study changes in the endomembrane system of barley (Hordeum vulgare L. cv. Himalaya) aleurone protoplasts. Protoplasts were used for this study because their response to calcium and the plant hormone gibberellic acid (Ga3) can be monitored prior to rapid freezing of cells for electron microscopy. Protoplasts incubated in Ga3 plus Ca2+ secrete elevated levels of a-amylase relative to cells incubated in Ga3 or Ca2+ alone. The endoplasmic reticulum (ER) and Golgi apparatus of protoplasts incubated in Ga3 plus Ca2+ undergo changes that are well correlated with the synthesis and secretion of a-amylase. The ER, which appears as short, single sheets …

Alix regulates egress of hepatitis B virus naked capsid particles in an ESCRT-independent manner

2010

Hepatitis B virus (HBV) is an enveloped DNA virus that exploits the endosomal sorting complexes required for transport (ESCRT) pathway for budding. In addition to infectious particles, HBV-replicating cells release non-enveloped (nucleo)capsids, but their functional implication and pathways of release are unclear. Here, we focused on the molecular mechanisms and found that the sole expression of the HBV core protein is sufficient for capsid release. Unexpectedly, released capsids are devoid of a detectable membrane bilayer, implicating a non-vesicular exocytosis process. Unlike virions, naked capsid budding does not require the ESCRT machinery. Rather, we identified Alix, a multifunctional …

Consensus based distributed estimation of biomass concentration in reverse osmosis membranes

2015

The correct estimation of biofilm formation in industrial environments, such as reverse osmosis plants, has become a topic of great interest. The occurrence of this natural process is the cause of huge economic losses due to a decrease of performance and maintenance costs in these plants. Current solutions based on water pretreatment or the dozing of biocides are not effective due to the lack of information about the state of the biofilm in the water system. In this work, we propose the use of a wireless sensor network that, based on the measurement of the biofilm thickness growth at the substratum of each sensor, estimates the biomass concentration within the biofilm, and, eventually, the …

An evidence based therapeutic approach to hereditary and acquired angioedema

2014

Purpose of review Hereditary angioedema (HAE) due to C1 esterase inhibitor (C1-INH) deficiency (HAE-C1-INH), HAE with normal C1-INH, and acquired angioedema due to C1-INH deficiency are rare but important diseases that can be associated with significant morbidity and mortality. Research into the pathogenesis of angioedema has expanded greatly and has led to new clinical trials with novel therapeutic agents and strategies. Recent findings Strategies for managing HAE-C1-INH are aimed at treating acute attacks or preventing attacks through the use of prophylactic treatment. Agents available in Europe for treating acute attacks include plasma-derived C1-INH concentrates, a bradykinin B2 recepto…

Learning how to live together: genomic insights into prokaryote–animal symbioses

2008

Our understanding of prokaryote-eukaryote symbioses as a source of evolutionary innovation has been rapidly increased by the advent of genomics, which has made possible the biological study of uncultivable endosymbionts. Genomics is allowing the dissection of the evolutionary process that starts with host invasion then progresses from facultative to obligate symbiosis and ends with replacement by, or coexistence with, new symbionts. Moreover, genomics has provided important clues on the mechanisms driving the genome-reduction process, the functions that are retained by the endosymbionts, the role of the host, and the factors that might determine whether the association will become parasitic…

PHENOLOGICAL ADAPTATION OF ANT-DISPERSED PLANTS TO SEASONAL VARIATION IN ANT ACTIVITY

2002

We studied a temperate plant community to examine whether the reproductive phenology of ant-dispersed plants is correlated with seasonal variation in seed dispersal activity of ants. We documented flowering and fruiting peak of 24 ant-dispersed and 251 non-ant-dispersed plant species. To characterize the activity of ants, we quantified the seasonal removal rates of greater celandine (Chelidonium majus) seeds. Ant-dispersed plants flowered on average 5.6 wk and fruited 7.1 wk earlier than those with other dispersal modes. This difference was not caused by variation in growth form or habitat. Mean fruiting peak of ant-dispersed plants was early July. Ant activity was especially high between M…

Bacteriophage GIL01 gp7 interacts with host LexA repressor to enhance DNA binding and inhibit RecA-mediated auto-cleavage

2015

The SOS response in Eubacteria is a global response to DNA damage and its activation is increasingly associated with the movement of mobile genetic elements. The temperate phage GIL01 is induced into lytic growth using the host's SOS response to genomic stress. LexA, the SOS transcription factor, represses bacteriophage transcription by binding to a set of SOS boxes in the lysogenic promoter P1. However, LexA is unable to efficiently repress GIL01 transcription unless the small phage-encoded protein gp7 is also present. We found that gp7 forms a stable complex with LexA that enhances LexA binding to phage and cellular SOS sites and interferes with RecA-mediated auto-cleavage of LexA, the ke…