Early Degradation Products Research Articles

Shedding light on the composition and degradation mechanism of dyes in historical ink's collection (19th-20th century)

Man has always used writing to be able to communicate, express, and disseminate his thoughts. In time, many different coloured extracts of plant and animal origin have been used to produce inks; after the development of synthetic chemistry, artificial and synthetic dyes started to be widely exploited. The end of the 19th century marked great technological and industrial innovations in commercial production of artists' materials. To reveal ink formulations and build a database of red inks by different producers, we developed a multi-analytical approach and investigated a collection of writing inks produced in France in the late 19th – early 20th century. The materials used as binders, additives, dyes, and pigments have been investigated by high performance liquid chromatography coupled with diode array and tandem mass spectrometric detectors (HPLC-DAD-MS2), in situ derivatisation pyrolysis coupled with gas chromatography-mass spectrometry (Py(HMDS)-GC/MS), surface enhanced Raman (SERS, TLC-SERS) and X-Ray Fluorescence spectroscopies. Several dyes and pigments were detected, showing that the French ink's formulations of the early days of synthetic dye industry were based on rhodamine B and 6G, eosin Y, rose Bengal and methyl or crystal violet. Instead, as binder and additives only gum Arabic and shellac resin have been identified, respectively. Mass spectrometry also allowed us to detect possible by-products of the synthesis of ink's dyes and even early degradation products, that can be used for ink identification in historical writings and drawings. Our studies can pave the way to investigate inks in historical samples by introducing ultra-sensitive chromatographic and mass spectrometric methods in the array of analytical tools available to the chemist.

Aerobic biotransformation of 6:2 fluorotelomer sulfonate by Dietzia aurantiaca J3 under sulfur-limiting conditions

The polyfluorinated alkyl substance 6:2 fluorotelomer sulfonate (6:2 FTS) has been detected in diverse environments impacted by aqueous film-forming foams used for firefighting. In this study, a bacterial strain (J3) using 6:2 FTS as a sulfur source was isolated from landfill leachate previously exposed to polyfluoroalkyl substances in New South Wales, Australia. Strain J3 shares 99.9% similarity with the 16S rRNA gene of Dietzia aurantiaca CCUG 35676T. Genome sequencing yielded a draft genome sequence of 37 contigs with a G + C content of 69.7%. A gene cluster related to organic sulfur utilisation and assimilation was identified, that included an alkanesulfonate monooxygenase component B (ssuD), an alkanesulfonate permease protein (ssuC), an ABC transporter (ssuB), and an alkanesulfonate-binding protein (ssuA). Proteomic analyses comparing strain J3 cultures using sulfate and 6:2 FTS as sulfur source indicated that the ssu gene cluster was involved in 6:2 FTS biodegradation. Upregulated proteins included the SsuD monooxygenase, the SsuB transporter, the ABC transporter permease (SsuC), an alkanesulfonate-binding protein (SsuA), and a nitrilotriacetate monooxygenase component B. 6:2 Fluorotelomer carboxylic acid (6:2 FTCA) and 6:2 fluorotelomer unsaturated acid (6:2 FTUA) were detected as early degradation products in cultures (after 72 h) while 5:3 fluorotelomer acid (5:3 FTCA), perfluorohexanoic acid (PFHxA) and perfluoropentanoic acid (PFPeA) were detected as later degradation products (after 168 h). This work provides biochemical and metabolic insights into 6:2 FTS biodegradation by the Actinobacterium D. aurantiaca J3, informing the fate of PFAS in the environment.

Degradation of fluoroquinolone antibiotics during ionizing radiation treatment and assessment of antibacterial activity, toxicity and biodegradability of the products

This work aimed at investigating the ionizing radiation induced degradation of two fluoroquinolone antibiotics: norfloxacin and ciprofloxacin. At 0.1 mmol dm−3 concentration a low dose, 2 kGy was sufficient to degrade the initial molecules. However, despite of the high removal efficiency the degrees of both the mineralization and the oxidation were low, ∼10% and ∼25%, respectively. (The difference between the results obtained in norfloxacin and ciprofloxacin solutions was not statistically significant.) Broth microdilution tests carried out on Staphylococcus aureus evidenced removal of antibacterial activity in samples irradiated with 2 kGy. Acute toxicity determined on Vibrio fischeri bacteria showed increased toxicity at low doses indicating that the early degradation products were more toxic than the initial molecules. The results of biodegradation experiments performed in activated sludge have shown that the degradation products have become available to the metabolic processes of the microorganisms.

Process of the degradation in vivo and biosafety of biodegradable magnesium alloy stent

Objective: To observe the degradation process of biodegradable magnesium alloy stent (BMAS) in vivo in order to evaluate its degradation time and biological safety. Methods: Twenty-four male New Zealand white rabbits were divided into two groups: group A (n=12) and group B (n=12). The BMAS (a total of 12) was implanted in the infrarenal aorta of each rabbit in group A, while group B was the control group, without treatment. Color Doppler ultrasound was used at the 1, 2, 3, 4 months postoperatively to observe the degradation process of stents in group A. The arterial blood samples and main organs of two groups were also collected for biochemical examination and biosafety. Degradation assessment included transmission X-ray tomography (XRT), scanning electron microscope (SEM) and energy dispersion spectrum (EDS). Results: The XRT showed that the morphology of the stent was basically intact at 1 month after implantation, then scaffold composites were gradually degraded and absorbed. Degradation was basically completed at 4 months after operation. The early degradation products were Mg(2+) , then gradually replaced by Ca(2+) , P and other inorganic composition. There was no obvious adverse reactions in group A during the 4 months follow-up period. There was no statistical difference between the two groups in blood biochemical and pathological results (all P>0.05). Conclusion: BMAS can be degraded within 4 months in the abdominal aorta of rabbit, and the main degradation products are Ca(2+) and P, with good biosafety.

Wood Liquefaction: Role of Solvent

The liquefaction of lignocellulose is strongly affected by the choice of the liquefaction solvent. This effect was studied by processing pinewood at 310 °C in various organic solvents, including some refinery streams. The impact on yields of char, biocrude, and gas was determined. The resulting biocrude was analyzed with GPC and GC-MS, the solid residue with FTIR and HR-SEM, and the gas with GC. The solvents appeared to influence the liquefaction through interaction with early carbohydrate degradation products rather than interaction with the final biocrude. Indeed, biocrude is soluble in all solvents, and char is not formed by degradation of biocrude but rather by degradation of early carbohydrate intermediates. Effective solvents show a good affinity with the biomass, e.g., as expressed by Hildebrand values of 25–40 MPa1/2 or small Hansen distances (Ra) to cellulose and lignin. Protic solvents further slowed the liquefaction reaction.

Unraveling Curcumin Degradation: AUTOXIDATION PROCEEDS THROUGH SPIROEPOXIDE AND VINYLETHER INTERMEDIATES EN ROUTE TO THE MAIN BICYCLOPENTADIONE

Curcumin is a dietary anti-inflammatory and chemopreventive agent consisting of two methoxyphenol rings connected by a conjugated heptadienedione chain. Curcumin is unstable at physiological pH and rapidly degrades in an autoxidation reaction to a major bicyclopentadione product in which the 7-carbon chain has undergone oxygenation and double cyclization. Early degradation products (but not the final bicyclopentadione) mediate topoisomerase poisoning and possibly many other activities of curcumin, but it is not known how many and what autoxidation products are formed, nor their mechanism of formation. Here, using [(14)C2]curcumin as a tracer, seven novel autoxidation products, including two reaction intermediates, were isolated and identified using one- and two-dimensional NMR and mass spectrometry. The unusual spiroepoxide and vinylether reaction intermediates are precursors to the final bicyclopentadione product. A mechanism for the autoxidation of curcumin is proposed that accounts for the addition and exchange of oxygen that have been determined using (18)O2 and H2(18)O. Several of the by-products are formed from an endoperoxide intermediate via reactions that are well precedented in lipid peroxidation. The electrophilic spiroepoxide intermediate formed a stable adduct with N-acetylcysteine, suggesting that oxidative transformation is required for biological effects mediated by covalent adduction to protein thiols. The spontaneous autoxidation distinguishes curcumin among natural polyphenolic compounds of therapeutic interest; the formation of chemically diverse reactive and electrophilic products provides a novel paradigm for understanding the polypharmacological effects of curcumin.

Degradation studies of methyl parathion with CuBTC metal-organic framework

Degradation of methyl parathion (MP) adsorbed in metal-organic framework (MOF-199) cages was studied using solid-state 31P nuclear magnetic resonance (NMR), Raman spectrometry, and solvent extractions. MP degradation was confirmed to be occurring when adsorbed in CuBTC MOF (MOF-199). Over 67 days of treatment, NMR results show that constitutional isomerization is an early mechanism of methyl parathion degradation with smaller amounts of oxidation (methyl paraoxon) and direct hydrolysis of MP followed by hydrolysis of these early degradation products. Raman spectrometry after 5 days and water extractions after 5 and 35 days supported this conclusion. 4-Nitrophenyl, a common MP degradation product, was observed with the amount increasing with exposure time or higher MP loading. Degradation of organic compounds such as methyl parathion, in addition to the selective physisorption, demonstrates the usefulness of MOF-199 for potential applications in protective materials and filtration.

Hemostatic system in chronic obstructive pulmonary disease with concomitant obesity

The examination of patients with chronic obstructive pulmonary disease with concomitant obesity established the presence of hypercoagulable changes, the severity of which depended on its degree. All this, along with the positive results of paracoagulation samples, increasing of soluble fibrin monomer complexes and early degradation products of fibrinogen in the blood, suggest the presence of chronic disseminated intravascular coagulation with prolonged retention of hypercoagulable in such pathology.

Diagenetic degradation products of bacteriohopanepolyols produced by Rhodopseudomonas palustris strain TIE-1

Hopanoids are pentacyclic triterpenoids commonly found in soils and sediments and are used as biomarkers for recent or past bacterial communities. While hopanes are the ultimate degradation products of bacteriohopanepolyols (BHPs), only a few BHPs, such as 32,35-anhydrobacteriohopanetetrol (anhydroBHT), have been identified as early diagenetic degradation products. Here, we report on diagenetic degradation products of BHPs produced by Rhodopseudomonas palustris strain TIE-1 after exposure to elevated pressure and temperature. While bacteriohopanetetrol (BHT) was degraded to various anhydroBHT isomers, new N-containing degradation products were discovered and tentatively assigned as anhydroaminotriols.

Hydrodynamic and mass spectrometry analysis of nearly-intact human fibrinogen, chicken fibrinogen, and of a substantially monodisperse human fibrinogen fragment X

The shape and solution properties of fibrinogen are affected by the location of the C-terminal portion of the Aalpha chains, which is presently still controversial. We have measured the hydrodynamic properties of a human fibrinogen fraction with these appendages mostly intact, of chicken fibrinogen, where they lack 11 characteristic 13-amino acids repeats, and of human fragment X, a plasmin early degradation product in which they have been removed. The human fibrinogen/fragment X samples were extensively characterized by SDS-PAGE/Western blotting and mass spectrometry, allowing their composition to be precisely determined. The solution properties of all samples were then investigated by analytical ultracentrifugation and size-exclusion HPLC coupled with multi-angle light scattering and differential pressure viscometry detectors. The measured parameters suggest that the extra repeats have little influence on the overall fibrinogen conformation, while a significant change is brought about by the removal of the C-terminal portion of the Aalpha chains beyond residue Aalpha200.

Sources of hydrocarbons in sediments of the Bay of Fort de France (Martinique)

Sedimentary hydrocarbons have been studied quantitatively and qualitatively in 16 stations of the Bay of Fort de France (Martinique). Hydrocarbon levels ranged from 54 to 1045 mg kg −1 sed. dry weight. Origin of hydrocarbons are multiple: biogenic (terrestrial inputs), pyrolytic (residues of natural or anthropogenic combustions), diagenetic and anthropogenic (petroleum contamination). Generally high levels of hydrocarbons are not associated to a petroleum contamination. The main source of hydrocarbons in the mangrove coastal zones of the Bay of Fort de France seems to be the early diagenetic degradation products of 3-oxytriterpenoids. Excepted two stations, petroleum contamination is very low or absent.

Early Dural Reaction to Polylactide in Cranial Defects in Rabbits

Restoring the bone integrity to injured calvariae remains a challenge to surgeons. In this study, the dural biocompatibility of biodegradable poly-L/DL-lactide 80/20 and 70/30 defect covers, designed for guided bone regeneration, was assessed. In each of the 16 test rabbits, bilateral (8.3 mm) cranial defects were created. The different covers were applied to one defect each in every rabbit and consisted of three parts: an epicranial cover, a spacer, and a dural cover. All defects had closed after 8 weeks due to new bone formation. A few giant cells were found at the cover-to-dura interface in equal numbers for both covers. Dural bone formation was present in 15 of 16 rabbits and progressed unhindered by the defect cover or its early degradation products.

Fibrinogen and fragment D-induced vascular constriction

Elevated fibrinogen (Fg) concentration in blood is a high risk factor for many cardiovascular diseases. We hypothesize that Fg and its early degradation product, fragment D, may result in arterial constriction by binding endothelial intercellular adhesion molecule-1 (ICAM-1). The vasoconstriction induced by Fg and fragment D was studied in third- and second-order arterioles (3As and 2As, respectively) of Sprague-Dawley rat cremaster muscle in vivo, in aortic and femoral artery rings, and in the segments of first-order arterioles (1As) isolated from rat cremaster muscle. Intravascular infusion of Fg induced significant constriction of 3As and 2As (by 33.4 +/- 3.4 and 23.7 +/- 4.3%, respectively) in vivo and was abolished in the presence of the specific endothelin type A receptor blocker BQ-610. Fg and fragment D produced significant constriction of both aortic and femoral artery rings. Isolated 1As constricted in response to Fg (0.3 microM) and fragment D (3 microM) by 31 +/- 1.4 and 12 +/- 1.5%, respectively. Fluorescently labeled Fg and fragment D bound to the vascular wall, whereas albumin bound to a significantly lesser degree. The binding of Fg and fragment D to the arteriolar wall and constriction of aortic and femoral artery rings as well as isolated 1As were abolished in the presence of anti-Fg and anti-ICAM-1 antibodies. These results indicate that binding of Fg and fragment D to the vascular wall through ICAM-1 may contribute to the increased vascular tone and resistance that compromise circulation.

Transient physical forcing of pulsed export of bioreactive material to the deep Sargasso Sea

Considerable attention has recently been focused on the role of eddies in affecting biogeochemical fluxes and budgets of the Sargasso Sea. In late November 1996, the Bermuda Testbed Mooring (BTM) and Bermuda Atlantic Time Series (BATS) shipboard sampling evidenced a fall phytoplankton bloom at the Bermuda time-series site which was strongly forced by the interplay between seasonal mixed layer destratification and perturbation of mixed layer dynamics due to passage of a warm mesoscale feature. The feature was characterized by clockwise current vector rotation from near the surface to about 200 m and a thick, warm, low salinity isothermal layer >180 m in depth. Nutrients, chlorophyll fluorescence and pigment profiles indicated high primary production stimulated by enhancement of nutrient entrainment and intermittent deep mixing down to the base of the feature's isothermal layer. Nearly coincident with the arrival of this productive feature at the BTM site, the Oceanic Flux Program (OFP) sediment traps recorded an abrupt, factor of 2.5 increase in mass flux at 3200 m depth. Even more dramatic was the observed increase in flux of labile bioreactive organic matter. Fluxes of primary phytoplankton-derived compounds increased by factors of 7–30, bacteria-derived compounds by 6–9, and early degradation products of sterols by a factor of 10. The covariation of early degradation products and bacteria-derived compounds with phytoplankton-derived compounds indicated that the settling phytoplankton bloom material contained elevated bacterial populations and was undergoing active degradation when it entered the 3200 m trap cup. The increase in the flux of bulk components, especially the residual silicate fraction, and refractory organic compounds clearly preceded the main pulse of the labile, surface-derived phytoplankton organic material. The coincident increase in the flux of refractory and zooplankton-derived compounds suggests that in the initial stage of the deep flux event, the mass flux increased largely as a result of an increase in the flux of refractory materials scavenged from the water column and repackaged into sinking particles and increased zooplankton inputs. These results imply that biological reprocessing of flux material within the water column acts to enhance the coupling between the surface and deep ocean environments. Our results show that transient, upper ocean forcing associated with variable upper ocean physical structure—which includes but is not limited to eddies—and variable meteorological forcing can have an enormous effect on the export flux of bioreactive organic material. The importance of pulsed fluxes of bioreactive material arising from transient physical forcing to the long-term average is not presently known. However, the occurrence of episodic high flux events throughout the OFP time-series record (also inferred from BTM time-series) suggests that such forcing, regardless of specific dynamics, may be responsible for a significant fraction of the total export flux of bioreactive carbon and associated elements to the deep oligotrophic ocean.

Carotenoids Induce Apoptosis in the T-lymphoblast Cell Line Jurkat E6.1

Epidemiologically, a high-carotenoid intake via a fruit- and vegetable-rich diet is associated with a decreased risk of various forms of cancer. The mechanisms by which carotenoids exert this protective effect are controversial. In this study, we examined the potency of a range of carotenoids commonly found in human plasma to induce apoptosis in Jurkat E6.1 malignant T-lymphoblast cells. At a concentration of 20 w M, the order of potency to induce apoptosis after 24 h was: g -carotene > lycopene > lutein> g -cryptoxanthin=zeaxanthin. Canthaxanthin failed to induce apoptosis under these conditions. g -Carotene induced apoptosis in a time- and concentration-dependent manner with a lowest effective concentration of about 3 w M. Pre-conditioning of g -carotene for 72 h destroyed its pro-apoptotic activity almost completely, whereas degradation for 6 h or less did not, indicating that either g -carotene itself and/or an early degradation product of g -carotene are the death-inducing compounds. Apoptosis induced by g -carotene was characterized by chromatin condensation and nuclear fragmentation, DNA degradation, PARP cleavage and caspase-3 activation. The antioxidant BO-653 inhibited the degradation of g -carotene in vitro and significantly increased its cytotoxicity, indicating that a pro-oxidant effect of g -carotene is unlikely to cause its pro-apoptotic activity. The induction of apoptosis in transformed cells by carotenoids may explain their protective effect against cancer formation in humans. Possible pathways for induction of apoptosis by carotenoids are discussed.

Variation in the chemistry of the TiO 2-mediated degradation of hydroxy- and methoxybenzenes: electron transfer and HO ads[rad] initiated chemistry

The early degradation product distributions from TiO 2-mediated photocatalytic degradations of a series of multiply hydroxylated benzenes and their methoxylated analogs is reported. The methoxylated compounds show a distinct trend away from ring-opening reactions that are attributed to electron transfer chemistry towards hydroxylations and demethylations that are attributed to hydroxyl-type chemistry. The initial rates of the reactions suggest that this is not simply due to the availability of the extra carbon sites. It is instead hypothesized that the compounds with hydroxyl groups are bound to the TiO 2 in such a way as to facilitate electron transfer and its subsequent chemistry. Addition of isopropyl alcohol to the degradations slows the degradations of the methoxylated compounds more than it does the hydroxylated compounds and particularly inhibits the demethylation and hydroxylation reactions. It is suggested that the question of whether an organic substrate must be bound to the photocatalyst at the time of excitation may be dependent on the type of chemistry being observed.

Monocytic cell adhesion to intact and plasmin-modified fibrinogen: possible involvement of Mac-1 (CD11b/CD18) and ICAM-1 (CD54).

beta(2)-integrin Mac-1 and immunoglobulin-like ICAM-1 adhesion molecules are expressed by monocytes and both known to bind fibrinogen and its degradation products. Here, we investigated whether fibrinogen cleavage with plasmin modulates the adherence of monocytic cells and what types of adhesion molecules are involved. Using several cell types, characterized by different patterns of Mac-1 and ICAM-1 expression, and monoclonal antibodies against beta(2)-integrins and ICAM-1 we demonstrate, that fibrinogen cleavage evokes gradual decrease in beta(2)-integrin-dependent cell adhesion. Furthermore, generation of the early degradation products, fragments X and Y, by minimum cleavage of fibrinogen stimulates cell adhesion, mediated by ICAM-1.

Analytical Studies on the Oxidative Degradation of the Reactive Textile Dye Uniblue A

Oxidative degradation process of organic materials in wastewater is an area of significant current interest. In the case of commercial textile dyes, little is known about the structures of the actual products that can form once a dye has been submitted to oxidative conditions. Here, a product analysis approach was applied to identify some of the major early degradation products of Uniblue A (UBA) when reacted with peroxydisulfate (PDS). UBA is the vinyl sulfone form and major wastewater constituent of the commercial anthraquinone textile dye C.I. Reactive Blue 19. Using NMR, LC−MS, and Raman, four reaction products could be identified, and possible reaction pathways are discussed.

Analytical Studies on the Oxidative Degradation of the Reactive Textile Dye Uniblue A

Oxidative degradation process of organic materials in wastewater is an area of significant current interest. In the case of commercial textile dyes, little is known about the structures of the actual products that can form once a dye has been submitted to oxidative conditions. Here, a product analysis approach was applied to identify some of the major early degradation products of Uniblue A (UBA) when reacted with peroxydisulfate (PDS). UBA is the vinyl sulfone form and major wastewater constituent of the commercial anthraquinone textile dye C.I. Reactive Blue 19. Using NMR, LC−MS, and Raman, four reaction products could be identified, and possible reaction pathways are discussed.

Range of activity and metabolic stability of synthetic antibacterial glycopeptides from insects

Antibacterial glycopeptides isolated from insects are exciting bio-oligomers because they represent a family of compounds in which the structural and functional effects of incorporating short O-linked sugars to protein fragments can be studied. Additionally, their high activity in vitro warrants detailed further drug development efforts. Due to the limited availability of the isolated material, we used synthetic glycopeptides and some analogs to investigate the range of activity of drosocin and pyrrhocoricin. While addition of the Gal–GalNAc disaccharide to the natural mid-chain position generally increased the antibacterial activity of drosocin, pyrrhocoricin lacking sugar appeared to be more potent, with an IC 50 against Escherichia coli D22 of 150 nM. Although glycosylated drosocin was active against E. coli in the low μM range in vitro, this peptide was completely inactive when injected into mice. The lack of in vivo activity of drosocin could be explained by the unusually high degradation rate of the peptides in mammalian sera. The early degradation products were inactive in vitro. In contrast, the peptides were considerably more stable in insect hemolymph, where their natural activity is manifested.