Phospholipases and Reactive Oxygen Species Derived Lipid Biomarkers in Healthy and Diseased Humans and Animals – A Focus on Lysophosphatidylcholine

Phospholipids (PL) are converted into lipid biomarkers by the action of phospholipases and reactive oxygen species (ROS), which are activated or released under certain physiological and pathophysiological conditions. Therefore, the in vivo concentration of such lipid biomarkers [e.g., lysophospholipids (LPLs)] is altered in humans and animals under different conditions such as inflammation, stress, medication, and nutrition. LPLs are particularly interesting because they are known to possess proand anti-inflammatory properties and may be generated by two different pathways: either by the influence of phospholipase A2 or by different reactive oxygen species that are generated in significant amounts under inflammatory conditions. Both lead to the cleavage of unsaturated acyl residues. This review provides a short summary of the mechanisms by which lipid biomarkers are generated under in vitro and in vivo conditions. The focus will be on lysophosphatidylcholine (LPC) because usually, this is the LPL species which occurs in the highest concentration and is, thus, easily detectable by chromatographic and spectroscopic methods. Finally, the effects of lipid biomarkers as signaling molecules and their roles in different human and animal pathologies such as infertility, cancer, atherosclerosis, and aging will be shortly discussed

Ultracold chemical reactions of a single Rydberg atom in a dense gas

Within a dense environment ($\rho \approx 10^{14}\,$atoms/cm$^3$) at ultracold temperatures ($T < 1\,\mu{}\text{K}$), a single atom excited to a Rydberg state acts as a reaction center for surrounding neutral atoms. At these temperatures almost all neutral atoms within the Rydberg orbit are bound to the Rydberg core and interact with the Rydberg atom. We have studied the reaction rate and products for $nS$ $^{87}$Rb Rydberg states and we mainly observe a state change of the Rydberg electron to a high orbital angular momentum $l$, with the released energy being converted into kinetic energy of the Rydberg atom. Unexpectedly, the measurements show a threshold behavior at $n\approx 100$ for the inelastic collision time leading to increased lifetimes of the Rydberg state independent of the densities investigated. Even at very high densities ($\rho\approx4.8\times 10^{14}\,\text{cm}^{-3}$), the lifetime of a Rydberg atom exceeds $10\,\mu\text{s}$ at $n > 140$ compared to $1\,\mu\text{s}$ at $n=90$. In addition, a second observed reaction mechanism, namely Rb$_2^+$ molecule formation, was studied. Both reaction products are equally probable for $n=40$ but the fraction of Rb$_2^+$ created drops to below 10$\,$% for $n\ge90$.Comment: 13 pages, 13 figure

hydrogen bonds and nuclear dynamics

Knowledge about the hydrogen bond network of water is essential for understanding its anomalies as well as its special role for biochemical systems. Different types of x-ray spectroscopy allow probing of the molecular orbitals of water, revealing the electronic structure which reflects the hydrogen bond conformations. In this work a recently developed high-resolution x-ray emission spectrometer was used in combination with the microjet technique for recording spectra of liquid H2O and D2O and their mixtures with acetonitrile. Variation of the nuclear dynamics via isotope substitution and variation of the hydrogen bond conformation via dissolution in acetonitrile was investigated. These two effects have two clearly distinguishable spectral fingerprints

Sperm Lipid Composition in Early Diverged Fish Species: Internal vs. External Mode of Fertilization

The lipid composition of sperm membranes is crucial for fertilization and differs among species. As the evolution of internal fertilization modes in fishes is not understood, a comparative study of the sperm lipid composition in freshwater representatives of externally and internally fertilizing fishes is needed for a better understanding of taxa-specific relationships between the lipid composition of the sperm membrane and the sperm physiology. The lipidomes of spermatozoa from stingray, a representative of cartilaginous fishes possessing internal fertilization, and sterlet, a representative of chondrostean fishes with external fertilization, have been studied by means of nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), electrospray MS, gas chromatography-(GC) MS, and thin-layer chromatography (TLC). NMR experiments revealed higher cholesterol content and the presence of phosphatidylserine in stingray compared to sterlet sperm. Unknown MS signals could be assigned to different glycosphingolipids in sterlet (neutral glycosphingolipid Gal-Cer(d18:1/16:0)) and stingray (acidic glycosphingolipid sulpho-Gal-Cer(d18:1/16:0)). Free fatty acids in sterlet sperm indicate internal energy storage. GC-MS experiments indicated a significant amount of adrenic acid, but only a low amount of docosahexaenoic acid in stingray sperm. In a nutshell, this study provides novel data on sperm lipid composition for freshwater stingray and sterlet possessing different modes of fertilization

oxygen K-edge X-ray absorption and emission spectroscopy on micro-jets

Oxygen K-edge X-ray absorption, emission, and resonant inelastic X-ray scattering spectra were measured to site selectively gain insights into the electronic structure of aqueous zinc acetate solution. The character of the acetate ion and the influence of zinc and water on its local electronic structure are discussed

Mycobacterium tuberculosis Affects Protein and Lipid Content of Circulating Exosomes in Infected Patients Depending on Tuberculosis Disease State

Tuberculosis (TB), which is caused by the bacterium Mycobacterium tuberculosis (Mtb), is still one of the deadliest infectious diseases. Understanding how the host and pathogen interact in active TB will have a significant impact on global TB control efforts. Exosomes are increasingly recognized as a means of cell-to-cell contact and exchange of soluble mediators. In the case of TB, exosomes are released from the bacillus and infected cells. In the present study, a comprehensive lipidomics and proteomics analysis of size exclusion chromatography-isolated plasma-derived exosomes from patients with TB lymphadenitis (TBL) and treated as well as untreated pulmonary TB (PTB) was performed to elucidate the possibility to utilize exosomes in diagnostics and knowledge building. According to our findings, exosome-derived lipids and proteins originate from both the host and Mtb in the plasma of active TB patients. Exosomes from all patients are mostly composed of sphingomyelins (SM), phosphatidylcholines, phosphatidylinositols, free fatty acids, triacylglycerols (TAG), and cholesterylesters. Relative proportions of, e.g., SMs and TAGs, vary depending on the disease or treatment state and could be linked to Mtb pathogenesis and dormancy. We identified three proteins of Mtb origin: DNA-directed RNA polymerase subunit beta (RpoC), Diacyglycerol O-acyltransferase (Rv2285), and Formate hydrogenase (HycE), the latter of which was discovered to be differently expressed in TBL patients. Furthermore, we discovered that Mtb infection alters the host protein composition of circulating exosomes, significantly affecting a total of 37 proteins. All TB patients had low levels of apolipoproteins, as well as the antibacterial proteins cathelicidin, Scavenger Receptor Cysteine Rich Family Member (SSC5D), and Ficolin 3 (FCN3). When compared to healthy controls, the protein profiles of PTB and TBL were substantially linked, with 14 proteins being coregulated. However, adhesion proteins (integrins, Intercellular adhesion molecule 2 (ICAM2), CD151, Proteoglycan 4 (PRG4)) were shown to be more prevalent in PTB patients, while immunoglobulins, Complement component 1r (C1R), and Glutamate receptor-interacting protein 1 (GRIP1) were found to be more abundant in TBL patients, respectively. This study could confirm findings from previous reports and uncover novel molecular profiles not previously in focus of TB research. However, we applied a minimally invasive sampling and analysis of circulating exosomes in TB patients. Based on the findings given here, future studies into host–pathogen interactions could pave the way for the development of new vaccines and therapies

Seminal lipid profiling and antioxidant capacity : a species comparison

On their way to the oocyte, sperm cells are subjected to oxidative stress, which may trigger the oxidation of phospholipids (PL). Applying MALDI-TOF MS, HPTLC and ESI-IT MS, we comparatively analyzed the PL compositions of semen and blood of species differing in their reproductive systems and types of nutrition (bull, boar, stallion, lion and man) with regard to the sensitivity to oxidation as well as the accumulation of harmful lyso-PL (LPL), transient products of lipid oxidation. In addition, the protective capacity of seminal fluid (SF) was also examined. The PL composition of erythrocytes and blood plasma is similar across the species, while pronounced differences exist for sperm and SF. Since the blood function is largely conserved across mammalian species, but the reproductive systems may vary in many aspects, the obtained results suggest that the PL composition is not determined by the type of nutrition, but by the relatedness of species and by functional requirements of cell membranes such as fluidity. Sperm motion and fertilization of oocytes require a rather flexible membrane, which is accomplished by significant moieties of unsaturated fatty acyl residues in sperm lipids of most species, but implies a higher risk of oxidation. Due to a high content of plasmalogens (alkenyl ether lipids), bull sperm are most susceptible to oxidation. Our data indicate that bull sperm possess the most effective protective power in SF. Obviously, a co-evolution of PL composition and protective mechanisms has occurred in semen and is related to the reproductive characteristics. Although the protective capacity in human SF seems well developed, we recorded the most pronounced individual contaminations with LPL in human semen. Probably, massive oxidative challenges related to lifestyle factors interfere with natural conditions.SUPPLEMENTARY MATERIAL: S1 Fig. ESI spectra of lysophosphatidylcholine (LPC) fractions from boar, bull, stallion, lion and human samples.S2 Fig. ESI spectra of sphingomyelin (SM) fractions from boar, bull, stallion, lion and human samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. SM fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the positive ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S2 Table. https://doi.org/10.1371/journal.pone.0264675.s002S3 Fig. ESI spectra of phosphatidylcholine (PC) fractions from boar, bull, stallion, lion and human samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PC fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the positive ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S3 Table. https://doi.org/10.1371/journal.pone.0264675.s003S4 Fig. ESI spectra of phosphatidylinositol (PI) fractions from boar, bull, stallion and human lipid samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PI fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the negative ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S4 Table. https://doi.org/10.1371/journal.pone.0264675.s004S5 Fig. ESI spectra of phosphatidylethanolamine (PE) fractions from boar, bull and stallion samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PE fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the negative ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S5 Table. https://doi.org/10.1371/journal.pone.0264675.s005S6 Fig. ESI spectra of phosphatidylethanolamine (PE) fractions from lion and human samples. Lipid extracts were separated on a normal phase high performance thin-layer chromatography (HPTLC) plate with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). Lipids were made visible under UV light and marked with a pencil. PE fractions were directly analyzed by coupling a TLC plate reader to an ESI mass spectrometer. Mass spectra were recorded in the negative ion mode. For further details on ESI-IT MS see main text. For peak assignment, please see S5 Table. https://doi.org/10.1371/journal.pone.0264675.s006S7 Fig. Hydrolysis of selected seminal fluid samples over time. The plots of hydrolysis measurements from boar and stallion seminal fluid were fitted by a linear curve (f(x) = a + b×x) and the plots from bull, lion and human were fitted by an exponential growth to a maximum (f(x) = a×e-b×x). Due to these different courses of the hydrolysis reaction between the species, the absolute hydrolysis at a given time point (10 min) was used to compare the mean values of the investigated individuals between the species (see Table 2 of the main text). https://doi.org/10.1371/journal.pone.0264675.s007S8 Fig. Effect of artificial LPC on boar sperm. Beltsville Thawing Solution (BTS, Minitüb GmbH)-diluted boar semen (20 × 106 sperm/ml) was mixed with 20 μM lysophosphatidylcholine (LPC 16:0, Avanti Polar Lipids®, No 855675C). After incubation at 38°C for 30 min, the ratios of total motility (blank boxes) and sperm with an intact acrosome (striped boxes) were analyzed. The lipid extract of washed sperm of this experiment was analyzed by MALDI-TOF MS and the ratio of LPC to total GPC was calculated (for details see Material and Methods of the main text). Incubation with 20 μM LPC led to 2.4 ± 3.6% inserted LPC in sperm cell membranes. Significant differences in total motility and the percentage of sperm with an intact acrosome between the incubation with 20 μM LPC and controls are marked by asterisks (P = 0.006 and 0.003, respectively, Wilcoxon signed-rank test, n = 11). https://doi.org/10.1371/journal.pone.0264675.s008S9 Fig. Original TLC pictures. Lipid extracts were separated on normal phase high performance thin-layer chromatography (HPTLC) plates with chloroform/ethanol/water/triethylamine (30:35:7:35, by vol.) as the mobile phase. Plates were air-dried and stained with primuline (Direct Yellow 59, Sigma-Aldrich, Taufkirchen, Germany) (50 mg/l dissolved in acetone/water 80:20, by vol.). BP–blood plasma, SF–seminal fluid, st.–lipid standard mixture made of LPC16:0, SM16:0, PC16:0/18:1, PA 16:0/18:1, PI 16:1/18:1, PE 16:0/18:1, PG 16:0/18:1 (bottom up). https://doi.org/10.1371/journal.pone.0264675.s009S1 Table. Assignment of signals detected in ESI spectra from lysophosphatidylcholine (LPC) spots. https://doi.org/10.1371/journal.pone.0264675.s010S2 Table. Assignment of signals detected in ESI spectra from sphingomyelin (SM) spots. n.a.—not assigned. https://doi.org/10.1371/journal.pone.0264675.s011S3 Table. Assignment of signals detected in ESI spectra from phosphatidylcholine (PC) spots. https://doi.org/10.1371/journal.pone.0264675.s012S4 Table. Assignment of signals detected in ESI spectra from phosphatidylinositol (PI) spots. https://doi.org/10.1371/journal.pone.0264675.s013S5 Table. Assignment of signals detected in ESI spectra from phosphatidylethanolamine (PE) spots. https://doi.org/10.1371/journal.pone.0264675.s014The German Research Council.http://www.plosone.orgdm2022Veterinary Tropical Disease

World checklist of hornworts and liverworts

A working checklist of accepted taxa worldwide is vital in achieving the goal of developing an online flora of all known plants by 2020 as part of the Global Strategy for Plant Conservation. We here present the first-ever worldwide checklist for liverworts (Marchantiophyta) and hornworts (Anthocerotophyta) that includes 7486 species in 398 genera representing 92 families from the two phyla. The checklist has far reaching implications and applications, including providing a valuable tool for taxonomists and systematists, analyzing phytogeographic and diversity patterns, aiding in the assessment of floristic and taxonomic knowledge, and identifying geographical gaps in our understanding of the global liverwort and hornwort flora. The checklist is derived from a working data set centralizing nomenclature, taxonomy and geography on a global scale. Prior to this effort a lack of centralization has been a major impediment for the study and analysis of species richness, conservation and systematic research at both regional and global scales. The success of this checklist, initiated in 2008, has been underpinned by its community approach involving taxonomic specialists working towards a consensus on taxonomy, nomenclature and distribution