Acid Tail Research Articles

Exposure to the Brominated Flame Retardant Hexabromocyclododecane Results in Systemic Changes in Polyunsaturated Fatty Acid Metabolism Within Phospholipids of Mice

Brominated flame retardants are used in many household products to reduce flammability, but often leach into the surrounding environment over time. Hexabromocyclododecane (HBCD) is one brominated flame retardant detected in human blood across the world. HBCD exposure can result in neurological problems and altered lipid metabolism, but to date the two remain unlinked. As lipids constitute ~50% of brain dry weight, lipid metabolism plays a critical role in neuronal function and homeostasis. To determine the effect of HBCD exposure on brain lipid metabolism, young adult male mice were exposed to 1 mg/kg HBCD every 3 days for 28 days. HBCD exposure altered lipid abundance of 8 major lipid classes in the dorsal striatum, including fatty acids (FA), lysophosphatidylcholines (LPC), lysophosphatidylethanolamines (LPE), phosphatidylcholines (PC), phosphatidylethanolamines (PE) alkylphosphatidylethanolamines (PEO), phosphatidylethanolamine plasmalogens (PEP), and sphingomyelins (SM). The liver, as a major lipid metabolism hub, and blood were also examined to determine whether these alterations correlated to systemic changes in lipid metabolism. Although several lipid classes changed in the liver and blood, only PE was consistently altered between organs. Despite the lack of commonalities between lipid class alterations of differing organs, phospholipid fatty acid tails displayed a consistent enrichment of Polyunsaturated Fatty Acids (PUFAs) such as Arachidonic Acid (AA) and Docosahexaenoic Acid (DHA) across lipid classes and organs. Free AA was enriched in the blood as well as AA contained within phospholipids of the liver (in PE), blood (in LPC, PEO, and PEP), and dorsal striatum (in PE, PEO). Additionally, although free DHA was unchanged in the blood, DHA‐containing phospholipids were enriched in the liver (in PE), blood (in LPC, LPE), and dorsal striatum (in PE, PEO, PEP, PS). These studies indicate that HBCD can cause systemic alterations in PUFA metabolism. Further study is necessary to determine the mechanisms underlying the lipid alterations and their functional consequences.

First Report of a Secovirus Associated with Mountain Celery Chlorotic Spot Disease in Heilongjiang, China.

Mountain celery (Heracleum moellendorffii Hance), an edible perennial herb of Northeast Asia, is sporadically cultivated as a vegetable crop or for medicinal purposes in Northeast China and Korea [1]. In July 2019, a small field of mountain celeries showing chlorotic spots was found in Wangkui, Heilongjiang, China. A small-RNA (sRNA) library was constructed with equal amounts of leaf tissues of a diseased mountain celery and a tomato sample showing mottling symptom from a nearby field using the TruSeq small RNA library preparation kit (Illumina). The library was sequenced by the HiSeq 4000 sequencer at Lianchuan Biotechnology Co., Ltd (Hangzhou, China). After trimming adaptor sequences and discarding low quality reads by Cutadapt [2], the remaining 6,949,946 reads of 17 to 27 nucleotides (nt) were de novo assembled as described [3]. The resulting 395 contigs were searched against the GenBank viral sequence database using the BLASTn and BLASTx algorithms. Twenty-three contigs showed high nt sequence similarities (89-100%) to the genomic sequence of tomato mosaic virus (ToMV). The deduced amino acid (aa) sequences of thirty contigs had 22-96% aa sequence identities to viruses in the family Secoviridae, e.g., surrounding non-legume associated secovirus (snLaSV) and lettuce secovirus 1 (LSV-1). No contig homologous to the genomic sequences of other plant viruses was identified. Total RNAs were extracted from the mountain celery and tomato separately and reverse transcribed into cDNAs by random hexamer plus Oligo-dT(18) using the Super® IV Reverse Transcriptase (Invitrogen, Shanghai, China). Polymerase chain reactions (PCR) showed that the secovirus was derived from the mountain celery, whereas the tomato was infected by ToMV. The genome of this secovirus was determined by reverse transcription (RT)-PCR and rapid amplification of cDNA ends (RACE). Amplicons were cloned and Sanger sequenced with at least three independent clones per amplicon. Sequences were assembled by the SeqMan Pro 7.1.0 in the Lasergene (DNASTAR, Madison, WI). The genome of this virus is composed of two RNAs of 6,616 and 5,356 nt (excluding the polyadenylic acid tails) (GenBank accession nos. MW143070 and MW143071, respectively). The thirty contigs assembled from sRNAs could be mapped to the genome. Pairwise sequence analyses showed that RNA1 and RNA2 and their encoded polyproteins shared the highest nt (82.7% and 82.2%) and aa (93.4% and 91.8%) sequence identities with the respective RNAs (GenBank accession nos. MN412739 and MN412740) and their encoded polyproteins of snLaSV [4]. In the phylogenetic trees, this virus sequence clustered with snLaSV and LSV-1 in a separate branch neighboring viruses of the subgenus Stramovirus or Satsumavirus in the genus Sadwavirus. These results suggest that this virus is an isolate of the unclassified snLaSV and was referred as snLaSV-CHN. RT-PCR with primers SecoR1-3700F and SecoR1-5100R confirmed the presence of snLaSV-CHN in other mountain celeries (11 of 23 tested) showing chlorotic spots symptoms but not in healthy ones from the same field. To the best of our knowledge, this is the first report of snLaSV infecting mountain celery in China and a more orthodox name, mountain celery chlorotic spot virus (MCCSV), is tentatively proposed. Our findings provide a better insight of the distribution and host range of this virus and further surveys are necessary to determine its incidence and damage in mountain celery. Funding: This study is financial supported by the Program for the Scientific Activities of Selected Returned Overseas Professionals in Heilongjiang Province (Grant No. 2018QD0002) and the China National Funds for Excellent Young Scientists (Grant No. 32022071). References Son, H. J. 2020. Food Sci Nutr. 9:514. Martin, M. 2011. EMBnet J. 17:10. Che, X., et al. 2020. Plant Dis. 104: 3085. Gaafar, Y. Z. A., et al. 2020. Front Microbiol. 11: 583242.

Molecular cloning and functional characterization of UBC13 and MMS2 from Candida albicans.

To maintain genome stability, eukaryotes have evolved a powerful DNA damage response system called DNA-damage tolerance (DDT) to deal with replication-blocking lesions. In the budding yeast Saccharomyces cerevisiae, K63-linked polyubiquitination of proliferating cell nuclear antigen (PCNA) is mediated by a Ubc13-Mms2 heterodimer, leading to error-free DDT. Candida albicans is one of the most studied fungal pathogens and to date no data regarding K63-linked ubiquitination or error-free DDT has been available. Here we report the identification and functional characterization of UBC13 and MMS2 genes from C. albicans. Both genes are highly conserved between S. cerevisiae and C. albicans. However, CaUbc13 differs from all other eukaryotes in that it contains a 21-amino acid tail that appears to attenuate its interaction with CaMms2, suggesting a possible regulatory mechanism in C. albicans. Both CaUBC13 and CaMMS2 genes can functionally rescue the corresponding budding yeast mutants from increased spontaneous mutagenesis and killing by DNA-damaging agents, indicating an error-free DDT pathway in C. albicans. Indeed Caubc13Δ/Δ and Camms2Δ/Δ null mutants were constructed and displayed characteristic sensitivity to DNA-damaging agents.

Structure-function relationships of membrane permeabilizing cyclic lipopeptides: be prepared for surprises

We have studied the membrane-permeabilizing activity of a series of synthetic analogs of cyclic lipopeptides (cLiPs) produced by Pseudomonas, mainly using calcein leakage assays via TCSPC. The effect of the N-terminal fatty acid tail of cLiPs was examined by analyzing the calcein leakage caused by several synthetic analogues of pseudodesmin A where its decyl fatty acid chain was replaced by a hexyl, octyl, dodecyl or tetradecyl chain. Furthermore, we studied the effect of peptide charge with respect to the selectivity for anionic versus zwitterionic membranes by using synthetic charge analogs of the anionic viscosin.

Structural defects of a supported lipid bilayer induced by photosensitized lipid oxidation

Unsaturated lipids (those with double bonds in their fatty acid tails) are particularly susceptible to oxidation via reactive oxygen species (ROS). These oxidized lipids are more polar, which causes a number of structural changes to the lipid bilayer membrane. The consequences of lipid oxidation include an increase in the area per lipid molecule which causes lateral membrane expansion, a decrease in lipid order, membrane thinning, increased membrane permeability, and others. Studies have also shown the induction of highly curved membrane structures, such as buds or tubes, upon lipid oxidation.

Evonik invests in biosurfactants

The specialty chemical maker Evonik Industries will spend what it describes as “a three-digit million-euro sum” to build a rhamnolipids plant at its site in Slovenská Ľupča, Slovakia. Evonik says the plant will be the world’s first commercial-scale facility for making the biosurfactant. Rhamnolipids are biodegradable surfactants made by fermenting sugar or oil and feature rhamnose sugar groups with fatty acid tails. In addition to strong environmental bona fides, rhamnolipids are more effective cleaners at lower concentrations than conventional surfactants while being gentler on skin and hair. Evonik already has customers in mind for the new capacity. “Our initial focus is on applications in personal and home care based on foaming, sensory, and mildness benefits as well as a pressing need to improve the sustainability profile of surfactants in these markets,” the firm says. The investment builds on a partnership between Evonik and the consumer product giant Unilever, which launched

Charged Polypeptide Tail Boosts the Salt Resistance of Enzyme-Containing Complex Coacervate Micelles.

Encapsulation of proteins can have advantages for their protection, stability, and delivery purposes. One of the options to encapsulate proteins is to incorporate them in complex coacervate core micelles (C3Ms). This can easily be achieved by mixing aqueous solutions of the protein and an oppositely charged neutral-hydrophilic diblock copolymer. However, protein-containing C3Ms often suffer from salt-inducible disintegration due to the low charge density of proteins. The aim of this study is to improve the salt stability of protein-containing C3Ms by increasing the net charge of the protein by tagging it with a charged polypeptide. As a model protein, we used CotA laccase and generated variants with 10, 20, 30, and 40 glutamic acids attached at the C-terminus of CotA using genetic engineering. Micelles were obtained by mixing the five CotA variants with poly(N-methyl-2-vinyl-pyridinium)-block-poly(ethylene oxide) (PM2VP128-b-PEO477) at pH 10.8. Hydrodynamic radii of the micelles of approximately 31, 27, and 23 nm for native CotA, CotA-E20, and CotA-E40, respectively, were determined using dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS). The encapsulation efficiency was not affected using enzymes with a polyglutamic acid tail but resulted in more micelles with a smaller number of enzyme molecules per micelle. Furthermore, it was shown that the addition of a polyglutamic acid tail to CotA indeed resulted in improved salt stability of enzyme-containing C3Ms. Interestingly, the polyglutamic acid CotA variants showed an enhanced enzyme activity. This study demonstrates that increasing the net charge of enzymes through genetic engineering is a promising strategy to improve the practical applicability of C3Ms as enzyme delivery systems.

Aromatic Sulfonamides including a Sulfonic Acid Tail: New Membrane Impermeant Carbonic Anhydrase Inhibitors for Targeting Selectively the Cancer-Associated Isoforms.

We report here a new drug design strategy for producing membrane-impermeant carbonic anhydrase (CA; EC 4.2.1.1) inhibitors selectively targeting the tumor-associated, membrane-bound human CAs IX and XII over off-target cytosolic isoforms. To date, this approach has only been pursued by including permanent positively charged pyridinium type or highly hydrophilic glycosidic moieties into the structure of aromatic sulfonamide CA inhibitors (CAIs). Aliphatic (propyl and butyl) sulfonic acid tails, deprotonated at physiological pH, were thus incorporated onto a benzenesulfonamide scaffold by a common 1,2,3-triazole linker and different types of spacers. Twenty such derivatives were synthesized and tested for their inhibition of target (hCAs IV, IX, and XII) and off-target CAs (hCAs I and II). Most sulfonate CAIs induced a potent inhibition of hCAs II, IX, and XII up to a low nanomolar KI range (0.9–459.4 nM) with a limited target/off-target CA selectivity of action. According to the drug design schedule, a subset of representative derivatives was assessed for their cell membrane permeability using Caco-2 cells and a developed FIA-MS/MS method. The complete membrane impermeability of the sulfonate tailed CAIs (≥98%) validated these negatively charged moieties as being suitable for achieving, in vivo, the selective targeting of the tumor-associated CAs over off-target ones.

Discovery of phenylpyrrolidine derivatives as a novel class of retinol binding protein 4 (RBP4) reducers

Retinol-binding protein 4 (RBP4) is a potential drug target for metabolic and ophthalmologic diseases. A high-throughput screening of our compound library has identified a small-molecule RBP4 reducer 7a, as a hit compound. Aiming to provide a suitable tool for investigating the pharmacological effects of RBP4 reducers, we conducted a structure–activity relationship study of 7a. Exploration of the aryl head, oxazole core, and propanoic acid tail of 7a resulted in the discovery of novel, potent, and orally available phenylpyrrolidine derivatives 43b and 43c. Compound 43b had a potent and long-lasting blood RBP4-level-reducing effect when orally administered to mice at a dose as low as 0.3 mg/kg.

Optical Control of Glycerolipids and Sphingolipids.

Glycerolipids, sphingolipids, and sterols are the three major classes of membrane lipids. Both glycerolipids and sphingolipids are comprised of combinations of polar headgroups and fatty acid tails. The fatty acid tail can be chemically modified with an azobenzene photoswitch giving rise to photoswitchable lipids. This approach has yielded a number of photopharmacological tools that allow for the control various of aspects of lipid assembly, metabolism, and physiology with light.

A Lipidomic Approach to Identify Potential Biomarkers in Exosomes From Melanoma Cells With Different Metastatic Potential.

Melanoma, one of the most lethal cutaneous cancers, is characterized by its ability to metastasize to other distant sites, such as the bone. Melanoma cells revealed a variable in vitro propensity to be attracted toward bone fragments, and melanoma-derived exosomes play a role in regulating the osteotropism of these cells. We have here investigated the lipid profiles of melanoma cell lines (LCP and SK-Mel28) characterized by different metastatic propensities to colonize the bone. We have purified exosomes from cell supernatants by ultracentrifugation, and their lipid composition has been compared to identify potential lipid biomarkers for different migration and invasiveness of melanoma cells. Matrix-assisted laser desorption ionization-time-of-flight/mass spectrometry (MALDI-TOF/MS) lipid analysis has been performed on very small amounts of intact parental cells and exosomes by skipping lipid extraction and separation steps. Statistical analysis has been applied to MALDI mass spectra in order to discover significant differences in lipid profiles. Our results clearly show more saturated and shorter fatty acid tails in poorly metastatic (LCP) cells compared with highly metastatic (SK-Mel28) cells, particularly for some species of phosphatidylinositol. Sphingomyelin, lysophosphatidylcholine, and phosphatidic acid were enriched in exosome membranes compared to parental cells. In addition, we have clearly detected a peculiar phospholipid bis(monoacylglycero)phosphate as a specific lipid marker of exosomes. MALDI-TOF/MS lipid profiles of exosomes derived from the poorly and highly metastatic cells were not significantly different.

Profiling of glycosphingolipids with SCDase digestion and HPLC-FLD-MS

Lipid components of cells and tissues feature a large diversity of structures that present a challenging problem for molecular analysis. Glycolipids from mammalian cells contain glycosphingolipids (GSLs) as their major glycolipid component, and these structures vary in the identity of the glycan headgroup as well as the structure of the fatty acid and sphingosine (Sph) tails. Analysis of intact GSLs is challenging due to the low abundance of these species. Here, we develop a new strategy for the analysis of lyso-GSL (l-GSL), GSL that retain linkage of the glycan headgroup with the Sph base. The analysis begins with digestion of a GSL sample with sphingolipid ceramide N-deacylase (SCDase), followed by labelling with an amine-reactive fluorophore. The sample was then analyzed by HPLC-FLD-MS and quantitated by addition of an external standard. This method was compared to analysis of GSL glycans after cleavage by an Endoglycoceramidase (EGCase) enzyme and labeling with a fluorophore (2-anthranilic acid, 2AA). The two methods are complementary, with EGCase providing improved signal (due to fewer species) and SCDase providing analysis of lyso-GSL. Importantly the SCDase method provides Sph composition of GSL species. We demonstrate the method on cultured human cells (Jurkat T cells) and tissue homogenate (porcine brain).

Antinociceptive, Anti-Hyperalgesia and Antiallodynic Activities of Polyphenol Rich Extract from Shorea roxburghii against Cyclophosphamide Induced Peripheral Neuropathy.

Cyclophosphamide (CYP) is a widely used antineoplastic and immunosuppressive drug, however, despite its efficacy, it has shown extensive multiple organ toxicities, including peripheral neuropathy which significantly affects the quality of life of cancer patients. This study elucidated the protective properties of Shorea roxburghii polyphenol extract (SLPE) in CYP-induced peripheral neuropathy. Rats were treated with SLPE (100 and 400 mg/kg) for five weeks plus CYP once a week from the second week of SLPE treatment. Using UHPLC-QTOF-MS, 54 polyphenolic compounds were identified in SLPE extract. After the treatment period the antinociceptive, anti-hyperalgesia and antiallodynic effects was evaluated using formalin paw edema, acetic acid abdominal writhing, hot plate, tail immersion and von Frey filament tests. While the locomotive and motor coordination effects were evaluated by open field and rotarod tests. The administration of CYP led to significant increases in mechanical and thermal hyperalgesia, in addition to hyper-nociceptive responses in the formalin and acetic acid writhing tests. CYP also significantly reduced locomotive activity and motor coordination. SLPE significantly protected against CYP-induced mechanical and thermal hyperalgesia. Furthermore, SLPE displayed robust antinociceptive effect by counteracting formalin and acetic acid induced hyper-nociception. In addition, SLPE increased the locomotive activity as well as the grip and motor coordination of the CYP treated rats. In conclusion, these results revealed the protective effects of SLPE against CYP-induced peripheral neuropathy and could be an effective therapeutic remedy for chemotherapy induced peripheral neuropathy.

Shear-Mediated Platelet Activation is Accompanied by Unique Alterations in Platelet Release of Lipids.

Platelet activation by mechanical means such as shear stress exposure, is a vital driver of thrombotic risk in implantable blood-contacting devices used in the treatment of heart failure. Lipids are essential in platelets activation and have been studied following biochemical activation. However, little is known regarding lipid alterations occurring with mechanical shear-mediated platelet activation. Here, we determined if shear-activation of platelets induced lipidome changes that differ from those associated with biochemically-mediated platelet activation. We performed high-resolution lipidomic analysis on purified platelets from four healthy human donors. For each donor, we compared the lipidome of platelets that were non-activated or activated by shear, ADP, or thrombin treatment. We found that shear activation altered cell-associated lipids and led to the release of lipids into the extracellular environment. Shear-activated platelets released 21 phospholipids and sphingomyelins at levels statistically higher than platelets activated by biochemical stimulation. We conclude that shear-mediated activation of platelets alters the basal platelet lipidome. Further, these alterations differ and are unique in comparison to the lipidome of biochemically activated platelets. Many of the released phospholipids contained an arachidonic acid tail or were phosphatidylserine lipids, which have known procoagulant properties. Our findings suggest that lipids released by shear-activated platelets may contribute to altered thrombosis in patients with implanted cardiovascular therapeutic devices. The online version contains supplementary material available at 10.1007/s12195-021-00692-x.

Multiple evidences of dynamic heterogeneity in hydrophobic deep eutectic solvents.

Hydrophobic deep eutectic solvents (HDESs) have gained immense popularity because of their promising applications in extraction processes. Herein, we employ atomistic molecular dynamics simulations to unveil the dynamics of DL-menthol (DLM) based HDESs with hexanoic (C6), octanoic (C8), and decanoic (C10) acids as hydrogen bond donors. The particular focus is on understanding the nature of dynamics with changing acid tail length. For all three HDESs, two modes of hydrogen bond relaxations are observed. We observe longer hydrogen bond lifetimes of the inter-molecular hydrogen bonding interactions between the carbonyl oxygen of the acid and hydroxyl oxygen of menthol with hydroxyl hydrogen of both acids and menthol. We infer strong hydrogen bonding between them compared to that between hydroxyl oxygen of acids and hydroxyl hydrogens of menthol and acids, marked by a faster decay rate and shorter hydrogen bond lifetime. The translational dynamics of the species in the HDES becomes slower with increasing tail length of the organic acid. Slightly enhanced caging is also observed for the HDES with a longer tail length of the acids. The evidence of dynamic heterogeneity in the displacements of the component molecules is observed in all the HDESs. From the values of the α-relaxation time scale, we observe that the molecular displacements become random in a shorter time scale for DLM-C6. The analysis of the self-van Hove function reveals that the overall distance covered by DLM and acid molecules in the respective HDES is more than what is expected from ideal diffusion. As marked by the shorter time scale associated with hole filling, the diffusion of the oxygen atom of menthol and the carbonyl oxygen of acid from one site to the other is fastest for hexanoic acid containing HDES.

Enterococcus faecalis Readily Adapts Membrane Phospholipid Composition to Environmental and Genetic Perturbation.

The bacterial lipid membrane, consisting both of fatty acid (acyl) tails and polar head groups, responds to changing conditions through alteration of either the acyl tails and/or head groups. This plasticity is critical for cell survival as it allows maintenance of both the protective nature of the membrane as well as functioning membrane protein complexes. Bacteria that live in fatty-acid rich environments, such as those found in the human host, can exploit host fatty acids to synthesize their own membranes, in turn, altering their physiology. Enterococcus faecalis is such an organism: it is a commensal of the mammalian intestine where it is exposed to fatty-acid rich bile, as well as a major cause of hospital infections during which it is exposed to fatty acid containing-serum. Within, we employed an untargeted approach to detect the most common phospholipid species of E. faecalis OG1RF via ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). We examined not only how the composition responds upon exposure to host fatty acids but also how deletion of genes predicted to synthesize major polar head groups impact lipid composition. Regardless of genetic background and differing basal lipid composition, all strains were able to alter their lipid composition upon exposure to individual host fatty acids. Specific gene deletion strains, however, had altered survival to membrane damaging agents. Combined, the enterococcal lipidome is highly resilient in response to both genetic and environmental perturbation, likely contributing to stress survival.

Structure-Activity Relationship Assessment of Sophorolipid Ester Derivatives against Model Bacteria Strains.

Sophorolipids (SLs) are glycolipids that consist of a hydrophilic sophorose head group covalently linked to a hydrophobic fatty acid tail. They are produced by fermentation of non-pathogenic yeasts such as Candida Bombicola. The fermentation products predominantly consist of the diacetylated lactonic form that coexists with the open-chain acidic form. A systematic series of modified SLs were prepared by ring opening of natural lactonic SL with n-alkanols of varying chain length under alkaline conditions and lipase-selective acetylation of sophorose primary hydroxyl groups. The antimicrobial activity of modified SLs against Gram-positive human pathogens was a function of the n-alkanol length, as well as the degree of sophorose acetylation at the primary hydroxyl sites. Modified SLs were identified with promising antimicrobial activities against Gram-positive human pathogens with moderate selectivity (therapeutic index, TI = EC50/MICB. cereus = 6–33). SL-butyl ester exhibited the best antimicrobial activity (MIC = 12 μM) and selectivity (TI = 33) among all SLs tested. Kinetic studies revealed that SL-ester derivatives kill B. cereus in a time-dependent manner resulting in greater than a 3-log reduction in cell number within 1 h at 2×MIC. In contrast, lactonic SL required 3 h to achieve the same efficiency.

The functional loss of ceramide metabolism enzymes ceramide synthase and acid sphingomyelinase on lipid metabolism and healthspan

The increase in our aging population in combination with the growing incidence of late-life conditions presents a need for research on healthy aging. Here, we present work examining the roles of sphingolipid metabolism on aging. Sphingolipids play important roles in stress response, cell survival, cell signaling, and aging. Specifically, ceramide responds to oxidative stress and recruits apoptotic proteins to the cell membrane thereby causing cell cycle arrest. Furthermore, ceramide levels increase with age, making it an important lipid mediator of aging. The objective of this study is to examine the physiological role of ceramide metabolism on aging and lipid metabolism pathways in the roundworm, Caenorhabditis elegans. To assess these mechanisms, we utilized C. elegans’ mutants lacking acid sphingomyelinase (asm-3) and ceramide synthase (hyl-2) which we previously found to be long- and short-lived respectively. We performed a lipidomic analysis to explore longitudinal changes in lipid concentrations in wild type (N2), asm-3/acid sphingomyelinase, and hyl-2/ceramide synthase worms at 1, 5, and 10 days of age. Among our samples, we detected 700 different lipids that were abundant enough in concentration for analysis. Interestingly, 10 day old hyl-2 mutants, which have a reduced life-span, showed an increased concentration of eicosapentaenoic acid (EPA), an omega-3 fatty acid that has been shown to increase with longevity in worms. Conversely, asm-3 mutants, which are long-lived animals, have reduced levels of EPA. To expand upon our lipidomic data with enzymatic findings, we utilized RT-qPCR analysis to longitudinally analyze fatty acid desaturases (fat-1 and fat-4) involved in EPA metabolism in worms. We found that fat-4 expression is reduced in 1, 5, and 10 day hyl-2 animals, suggesting that ceramide metabolism may impact fatty acid genes involved in aging. Future work will examine the role of stress response genes including superoxide dismutase (sod-3) and fatty acid tail elongases (elo-5 and elo-6) in 1, 5, and 10 day old hyl-2 and asm-3 mutants. Finally, to expand upon the current knowledge of ceramide's role in lifespan, we present data on the RNAi mediated suppression of hyl-2 in long-lived mutants including mitochondrial respiration (clk-1/coenzyme Q), insulin-like signaling (daf-2/insulin-like receptor), and dietary starvation (eat-2/mAChR). Our goal is to identify whether ceramide metabolism works within these known pathways that mediate aging. With these assays, we hope to better understand the intrinsic biochemical lipid processes associated with ceramide metabolism in aging animals.

RNA-seq analysis and gene expression dynamics in the salivary glands of the argasid tick Ornithodoros erraticus along the trophogonic cycle

BackgroundThe argasid tick Ornithodoros erraticus is the main vector of tick-borne human relapsing fever (TBRF) and African swine fever (ASF) in the Mediterranean Basin. Tick salivary proteins secreted to the host at the feeding interface play critical roles for tick feeding and may contribute to host infection by tick-borne pathogens; accordingly, these proteins represent interesting antigen targets for the development of vaccines aimed at the control and prevention of tick infestations and tick-borne diseases.MethodsTo identify these proteins, the transcriptome of the salivary glands of O. erraticus was de novo assembled and the salivary gene expression dynamics assessed throughout the trophogonic cycle using Illumina sequencing. The genes differentially upregulated after feeding were selected and discussed as potential antigen candidates for tick vaccines.ResultsTranscriptome assembly resulted in 22,007 transcripts and 18,961 annotated transcripts, which represent 86.15% of annotation success. Most salivary gene expression took place during the first 7 days after feeding (2088 upregulated transcripts), while only a few genes (122 upregulated transcripts) were differentially expressed from day 7 post-feeding onwards. The protein families more abundantly overrepresented after feeding were lipocalins, acid and basic tail proteins, proteases (particularly metalloproteases), protease inhibitors, secreted phospholipases A2, 5′-nucleotidases/apyrases and heme-binding vitellogenin-like proteins. All of them are functionally related to blood ingestion and regulation of host defensive responses, so they can be interesting candidate protective antigens for vaccines.ConclusionsThe O. erraticus sialotranscriptome contains thousands of protein coding sequences—many of them belonging to large conserved multigene protein families—and shows a complexity and functional redundancy similar to those observed in the sialomes of other argasid and ixodid tick species. This high functional redundancy emphasises the need for developing multiantigenic tick vaccines to reach full protection. This research provides a set of promising candidate antigens for the development of vaccines for the control of O. erraticus infestations and prevention of tick-borne diseases of public and veterinary health relevance, such as TBRF and ASF. Additionally, this transcriptome constitutes a valuable reference database for proteomics studies of the saliva and salivary glands of O. erraticus.Graphical

Efficient Prevention of Marine Biofilm Formation Employing a Surface-Grafted Repellent Marine Peptide.

Creation of surfaces resistant to the formation of microbial biofilms via biomimicry has been heralded as a promising strategy to protect a range of different materials ranging from boat hulls to medical devices and surgical instruments. In our current study, we describe the successful transfer of a highly effective natural marine biofilm inhibitor to the 2D surface format. A series of cyclic peptides inspired by the natural equinatoxin II protein produced by Beadlet anemone (Actinia equine) have been evaluated for their ability to inhibit the formation of a mixed marine microbial consortium on polyamide reverse osmosis membranes. In solution, the peptides are shown to effectively inhibit settlement and biofilm formation in a nontoxic manner down to 1 nM concentrations. In addition, our study also illustrates how the peptides can be applied to disperse already established biofilms. Attachment of a hydrophobic palmitic acid tail generates a peptide suited for strong noncovalent surface interactions and allows the generation of stable noncovalent coatings. These adsorbed peptides remain attached to the surface at significant shear stress and also remain active, effectively preventing the biofilm formation over 24 h. Finally, the covalent attachment of the peptides to an acrylate surface was also evaluated and the prepared coatings display a remarkable ability to prevent surface colonization at surface loadings of 55 ng/cm2 over 48 h. The ability to retain the nontoxic antibiofilm activity, documented in solution, in the covalent 2D-format is unprecedented, and this natural peptide motif displays high potential in several material application areas.