Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 16739973

Monitoring a complex medium fermentation with sample-sample two-dimensional FT-NIR correlation spectroscopy.

Ana P Ferreira·José C Menezes
View original source ↗Export metadata ↓

Abstract

The possibility of monitoring state transitions during the time course of a fermentation through the analysis of the on-line collected near-infrared (NIR) spectra with sample-sample two-dimensional correlation spectroscopy (SS-2DCoS) was investigated. SS-2DCoS has proved to be useful for extracting process information directly from the spectra collected on-line. The complexity of the system studied prevented the extraction of concentration profiles, but nevertheless, the application of SS-2DCoS enables the identification of fermentation state transitions due to metabolic and morphological changes of the microorganism.

Explore related subjects

Cells, CulturedFermentationIndustrial MicrobiologyOnline SystemsSensitivity and SpecificitySpectroscopy, Fourier Transform InfraredStreptomycesTime FactorsComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Ana P Ferreira, José C Menezes. Monitoring a complex medium fermentation with sample-sample two-dimensional FT-NIR correlation spectroscopy.. https://doi.org/10.1021/bp0503991

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Opposite effects of high glucose on MMP-2 and TIMP-2 in human endothelial cells.

Diabetes mellitus (DM) is a major risk factor for atherosclerosis and causes multiple cardiovascular complications. Although high glucose can induce matrix metalloproteinases (MMPs), its inhibitors and cell apoptosis, little is known about the roles of MMPs in regulating cell apoptosis in response to high glucose. To address this issue, we elucidated the relationship between MMPs, its inhibitors and cell apoptosis in human umbilical vein endothelial cells (HUVECs). HUVECs were treated with medium containing 5.5 mM or 33 mM of glucose in the presence or the absence of ascorbic acid and MMP inhibitors (GM6001 and endogenous tissue inhibitors of MMPs, TIMP-1, and TIMP-2). For detection of cell apoptosis, the cell death detection ELISA assay was used. The results revealed that high glucose-induced apoptosis could be suppressed by ascorbic acid, GM6001 and TIMP-2, but not by TIMP-1. The activities of MMP-2, MMP-9 and its inhibitors, TIMP-1, TIMP-2 after high glucose treatment, were also detected by ELISA method. We found that the activated form of MMP-2, but not MMP-9, was increased, while the level of TIMP-2, but not TIMP-1, was decreased. In Western blot and RT-PCR analysis, the expression of TIMP-2, but not TIMP-1, after high glucose treatment was downregulated, whereas the levels of MMP-2 and -9 proteins and mRNA were not changed. The present study indicated that oxidative stress induced by high glucose might be involved in the opposite effects on MMP-2 activation and TIMP-2 downregulation. This reactive oxygen species (ROS)-dependent MMP-2 activation in turn mediates high glucose-induced cell apoptosis in HUVECs.

Cells, Cultured↗
PubMed2007

Kinetic properties of mutant deoxyguanosine kinase in a case of reversible hepatic mtDNA depletion.

DGUOK [dG (deoxyguanosine) kinase] is one of the two mitochondrial deoxynucleoside salvage pathway enzymes involved in precursor synthesis for mtDNA (mitochondrial DNA) replication. DGUOK is responsible for the initial rate-limiting phosphorylation of the purine deoxynucleosides, using a nucleoside triphosphate as phosphate donor. Mutations in the DGUOK gene are associated with the hepato-specific and hepatocerebral forms of MDS (mtDNA depletion syndrome). We identified two missense mutations (N46S and L266R) in the DGUOK gene of a previously reported child, now 10 years old, who presented with an unusual revertant phenotype of liver MDS. The kinetic properties of normal and mutant DGUOK were studied in mitochondrial preparations from cultured skin fibroblasts, using an optimized methodology. The N46S/L266R DGUOK showed 14 and 10% residual activity as compared with controls with dG and deoxyadenosine as phosphate acceptors respectively. Similar apparent negative co-operativity in the binding of the phosphate acceptors to the wild-type enzyme was found for the mutant. In contrast, abnormal bimodal kinetics were shown with ATP as the phosphate donor, suggesting an impairment of the ATP binding mode at the phosphate donor site. No kinetic behaviours were found for two other patients with splicing defects or premature stop codon. The present study represents the first characterization of the enzymatic kinetic properties of normal and mutant DGUOK in organello and our optimized protocol allowed us to demonstrate a residual activity in skin fibroblast mitochondria from a patient with a revertant phenotype of MDS. The residual DGUOK activity may play a crucial role in the phenotype reversal.

Cells, Cultured↗
PubMed2007

Hemolytic uremic syndrome: a factor H mutation (E1172Stop) causes defective complement control at the surface of endothelial cells.

Defective complement regulation results in hemolytic uremic syndrome (HUS), a disease that is characterized by microangiopathy, thrombocytopenia, and acute renal failure and that causes endothelial cell damage. For characterization of how defective complement regulation relates to the pathophysiology, the role of the complement regulator factor H and also of a mutant factor H protein was studied on the surface of human umbilical vein endothelial cells. The mutant 145-kD factor H protein was purified to homogeneity, from plasma of a patient with HUS, who is heterozygous for a factor H gene mutation G3587T, which introduces a stop codon at position 1172. Functional analyses show that the lack of the most C-terminal domain short consensus repeats 20 severely affected recognition functions (i.e., binding to heparin, C3b, C3d, and the surface of endothelial cells). Wild-type factor H as well as the mutant protein formed dimers in solution as shown by cross-linking studies and mass spectroscopy. When assayed in fluid phase, the complement regulatory activity of the mutant protein was normal and comparable to wild-type factor H. However, on the surface of endothelial cells, the mutant factor H protein showed severely reduced regulatory activities and lacked protective functions. Similarly, with the use of sheep erythrocytes, the mutant protein lacked the protective activity and caused increased hemolysis when it was added to factor H-depleted plasma. This study shows how a mutation that affects the C-terminal region of the factor H protein leads to defective complement control on cell surfaces and damage to endothelial cells in patients with HUS. These effects explain how mutant factor H causes defective complement control and in HUS-particularly under condition of inflammation and complement activation-causes endothelial cell damage.

Cells, Cultured↗