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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,783 records · Page 99
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Non-thermal plasma reduces periodontitis-induced alveolar bone loss in rats

Periodontitis, a chronic infectious disease induced by microbial biofilm, is one of the most common diseases worldwide. Scaling and root planning (SRP) has always been recognized as the typical treatment. However, the therapeutic efficiency is often limited due to the intraoperative bleeding and the limitations of instruments. Non-thermal atmospheric plasma (NTP) appears to be a potential tool for periodontitis due to its promising biofilm degradation and decontamination effects. In this study, we investigated the role of NTP, as an adjuvant approach for the treatment of ligature-induced periodontitis in rats. Herein we showed that SRP or SRP-NTP application attenuated the periodontitis-induced alveolar bone loss, reflected by the increased BV/TV value and the decreased CEJ-AB distance, which might be related to the lower detection rate of periodontal pathogen in SRP and SRP-NTP groups. Besides, SRP-NTP rats showed less bone loss and lower CEJ-AB distance than that of SRP group at 30d post treatment, indicating a more comprehensive and long-lasting effect of SRP-NTP. A remarkable decrease of osteoclast number and lower expression of RANKL was also detected in SRP-NTP rats. In addition, expression of inflammatory-related cytokines such as TNF-α and IL-1β decreased significantly in SRP-NTP group, while IL-10 level increased substantially. These results together illustrated that a combination of SRP and NTP treatment was an effective way to prevent periodontitis progress, which reduced alveolar bone loss and promoted periodontium restoration in ligature-induced periodontitis rats. In conclusion, non-thermal plasma treatment may be considered as a feasible and effective supplementary approach to control periodontitis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

The heterozygous R155C VCP mutation: Toxic in humans! Harmless in mice?

Highlights: • Mutations of the human VCP gene cause several neurodegenerative diseases. • R155C VCP knock-in mice display multiple abnormalities but no typical VCP diseases. • Mutant VCP mRNA levels were markedly increased in man, but decreased in mice. • R155C VCP mRNA species in man and mice have different biological half lifes. Heterozygous missense mutations in the human VCP gene cause inclusion body myopathy associated with Paget disease of bone and fronto-temporal dementia (IBMPFD) and amyotrophic lateral sclerosis (ALS). The exact molecular mechanisms by which VCP mutations cause disease manifestation in different tissues are incompletely understood. In the present study, we report the comprehensive analysis of a newly generated R155C VCP knock-in mouse model, which expresses the ortholog of the second most frequently occurring human pathogenic VCP mutation. Heterozygous R155C VCP knock-in mice showed decreased plasma lactate, serum albumin and total protein concentrations, platelet numbers, and liver to body weight ratios, and increased oxygen consumption and CD8+/Ly6C + T-cell fractions, but none of the typical human IBMPFD or ALS pathologies. Breeding of heterozygous mice did not yield in the generation of homozygous R155C VCP knock-in animals. Immunoblotting showed identical total VCP protein levels in human IBMPFD and murine R155C VCP knock-in tissues as compared to wild-type controls. However, while in human IBMPFD skeletal muscle tissue 70% of the total VCP mRNA was derived from the mutant allele, in R155C VCP knock-in mice only 5% and 7% mutant mRNA were detected in skeletal muscle and brain tissue, respectively. The lack of any obvious IBMPFD or ALS pathology could thus be a consequence of the very low expression of mutant VCP. We conclude that the increased and decreased fractions of the R155C mutant VCP mRNA in man and mice, respectively, are due to missense mutation-induced, divergent alterations in the biological half-life of the human and murine mutant mRNAs. Furthermore, our work suggests that therapy approaches lowering the expression of the mutant VCP mRNA below a critical threshold may ameliorate the intrinsic disease pathology.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Structural insights into inhibitor binding to a fungal ortholog of aspartate semialdehyde dehydrogenase

Highlights: • Structure of an inhibitor bound to an essential fungal enzyme. • Effects of cofactor binding on oligomeric assembly. • Structure guided docking of a potent fungal enzyme inhibitor. • Structural comparison to related microbial enzymes. The aspartate pathway, uniquely found in plants and microorganisms, offers novel potential targets for the development of new antimicrobial drugs. Aspartate semialdehyde dehydrogenase (ASADH) catalyzes production of a key intermediate at the first branch point in this pathway. Several fungal ASADH structures have been determined, but the prior crystallization conditions had precluded complex formation with enzyme inhibitors. The first inhibitor-bound and cofactor-bound structures of ASADH from the pathogenic fungi Blastomyces dermatitidis have now been determined, along with a structural and functional comparison to other ASADH family members. The structure of this new ASADH is similar to the other fungal orthologs, but with some critical differences in the orientation of some active site functional groups and in the subunit interface region. The presence of this bound inhibitor reveals the first details about inhibitor binding interactions, and the flexible orientation of its aromatic ring provides helpful insights into the design of potentially more potent and selective antifungal compounds.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

GhUMC1, a blue copper-binding protein, regulates lignin synthesis and cotton immune response

Highlights: • Knock-down of GhUMC1 attenuates the cotton immune response. • GhUMC1 has a spatio-temporal regulation in cotton disease resistance. • GhUMC1 acts upstream of lignin synthesis and is involved in cell wall remodeling. Verticillium wilt caused by the soil-borne fungus Verticillium dahliae is a serious problem for the sustainable production of cotton. The mechanism of cotton resistance to V. dahliae is unclear, which makes it is difficult to improve cotton resistance breeding. In this study, we characterized an umecyanin-like gene GhUMC1 in cotton, which is homologous to the AtBCB gene in Arabidopsis. It is predominantly expressed in roots and responds to pathogen infection. Knock-down of GhUMC1 increases plant susceptibility to V. dahliae. Expression levels of genes in the JA and SA signaling pathways in roots were down-regulated in GhUMC1-silenced plants. The transcripts of lignin synthesis genes, such as C4H, HCT, CCoAOMT and CAD, were also decreased in GhUMC1 knock-down seedlings, as was lignin content. Interestingly, knock-down of the GhUMC1 also decreased the contents of H{sub 2}0{sub 2} compared with the control. Our results suggest that GhUMC1 is involved in cotton resistance to V. dahliae by the regulation of the JA signaling pathway and lignin metabolism.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Autoimmune sialadenitis is associated with the upregulation of chemokine/chemokine receptor pairs in T cell-specific TRAF6-deficient mice

Sialadenitis is an inflammatory condition affecting the salivary glands including the parotid, submandibular, and sublingual glands. There are several different types of sialadenitis, each with different sites of predilection. However, the pathogenic mechanism underlying the tissue specificity of sialadenitis is largely unknown. TRAF6 is a cytoplasmic adaptor protein that is necessary for the activation of dendritic cells in response to Toll-like receptor ligands, thereby regulating innate immune responses. We previously demonstrated that T cell-specific TRAF6-deficient mice (TRAF6ΔT mice) spontaneously develop systemic inflammatory disease. Here, we show that salivary secretion is reduced in TRAF6ΔT mice due to sialadenitis that occurs in the parotid and submandibular glands, but not the sublingual glands. Consistent with pathological findings, both CD4{sup +} and CD8{sup +} T cells predominantly infiltrated the submandibular glands; however, sublingual infiltration was rare in TRAF6ΔT mice. The TH1 cytokine IFN-γ, the TH1 cell attractant chemokine CCL2, and its cognate receptor CCR2 were upregulated concomitantly in both the submandibular and sublingual glands. Interestingly, the TH17 cell attractant chemokine CCL20 and its cognate receptor CCR6 were selectively increased in the submandibular glands, but not in the sublingual glands of TRAF6ΔT mice. Thus, the expression of TRAF6 in T cells might be implicated in tissue-specific sialadenitis by regulating the chemokine-chemokine receptor system.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Fibroblast growth factor 21 attenuates hypoxia-induced pulmonary hypertension by upregulating PPARγ expression and suppressing inflammatory cytokine levels

Highlights: • FGF21 Attenuates Hypoxia-induced Pulmonary Hypertension as a Potential drug. • FGF21 may Inhibit Vascular Remodeling Through Suppressing PASMCs Proliferation. • FGF21 Upregulates PPARγ Expression and Inhibits Inflammatory Cytokines. Hypoxia-induced pulmonary hypertension (HPH) is a progressive disease characterized by a sustained, elevated pulmonary arterial pressure and vascular remodeling. The latter pathogenesis mainly involves overproliferation of pulmonary artery smooth muscle cells (PASMCs). Fibroblast growth factor 21 (FGF21) has recently emerged as a novel regulator that prevents cardiac hypertrophic remodeling. However, its possible role in pulmonary remodeling remains unclear. The activation of peroxisome proliferator activated receptor γ (PPARγ) is reported to attenuate HPH by suppressing proliferative signals. Loss of PPARγ in the lung contributes to abnormal proliferation of PASMCs. FGF21 is a key regulator of PPARγ activity in adipocytes, but its role has not been elucidated in PASMCs. Therefore, we hypothesized that FGF21 may confer therapeutic effects in HPH by upregulating the expression of PPARγ. Sprague-Dawley rats were exposed to hypoxia and treated with FGF21 for 4 weeks. In parallel, hypoxic conditions and FGF21 were administered to rat PASMCs for 48 h. FGF21 attenuated the hypoxia-induced elevation in mean pulmonary arterial pressure (mPAP), right ventricular hypertrophy (RVH), medial thickening and overproliferation of PASMCs. Furthermore, FGF21 abrogated the reductions in PPARγ expression and increases in TNF-α, IL-1 and IL-6 levels in PASMC culture media. Collectively, these results demonstrate that FGF21 could potentially attenuate the pathogenic derangements of HPH by targeting PPARγ and inflammatory cytokines.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Wucherria bancrofti glutathione S-Transferase: Insights into the 2.3 Å resolution X-ray structure and function, a therapeutic target for human lymphatic filariasis

Highlights: • Crystal structure of W. bancrofti GST with its cofactor GSH at 2.3 Å resolution was determined. • Structural comparison against human GST reveals distinct differences in substrate binding sites. • GST xenobiotic binding site is more substrate accessible and reveals non-catalytic binding sites. • Enzyme kinetic assays reveal that antifilarial drug Diethyl carbamazine binds in an uncompetitive manner. • Structural features provide insights to support future design of parasite specific inhibitors. The notoriety of parasitic nematode survival is directly related to chronic pathogenicity, which is evident in human lymphatic filariasis. It is a disease of poverty which causes severe disability affecting more than 120 million people worldwide. These nematodes down-regulate host immune system through a myriad of strategies that includes secretion of antioxidant and detoxification enzymes like glutathione-S-transferases (GSTs). Earlier studies have shown Wuchereria bancrofti GST to be a potential therapeutic target. Parasite GSTs catalyse the conjugation of glutathione to xenobiotic and other endogenous electrophiles and are essential for their long-term survival in lymph tissues. Hence, the crystal structure of WbGST along with its cofactor GSH at 2.3 Å resolution was determined. Structural comparisons against host GST reveal distinct differences in the substrate binding sites. The parasite xenobiotic binding site is more substrate/solvent accessible. The structure also suggests the presence of putative non-catalytic binding sites that may permit sequestration of endogenous and exogenous ligands. The structure of WbGST also provides a case for the role of the π-cation interaction in stabilizing catalytic Tyr compared to stabilization interactions described for other GSTs. Hence, the obtained information regarding crucial differences in the active sites will support future design of parasite specific inhibitors. Further, the study also evaluates the inhibition of WbGST and its variants by antifilarial diethylcarbamazine through kinetic assays.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

A valine-to-lysine substitution at position 210 induces structural conversion of prion protein into a β-sheet rich oligomer

Highlights: • A V210I mutation has been associated with pathogenic conversion of PrP to PrP{sup Sc}. • A V210K mutation (but not the V210I mutation) impacts on the PrP structure. • The resulting structure adopts a β-sheet-rich oligomer with low stability. • A lysine substitution in the hydrophobic core induces the α→β conversion in vitro. Prion diseases are fatal neurodegenerative diseases associated with structural conversion of α-helical prion protein (PrP) into its β-sheet rich isoform (PrP{sup Sc}). Previous genetic analyses have indicated that several amino acid residues involved in the hydrophobic core of PrP (such as V180, F198, and V210) play a critical role in the development of prion diseases. To understand how these hydrophobic residues would contribute to the α-to-β conversion process of PrP, we substituted the V210 residue with bulkier (V210F, V210I, and V210L), smaller (V210A), and charged amino acids (V210K) and characterized its effects. Interestingly, although most of the mutations had little or no effect on the biochemical properties of PrP, the V210K mutation induced structural conversion of PrP into a β-structure. The β-inducing effect was prominent and observed even under a physiological condition (i.e., in the absence of denaturant, acidic pH, reducing agent, and high temperature) in contrast to the disease-associated mutations in the PrP gene. We also examined structural features of V210K PrP using guanidine-hydrochloride unfolding, dynamic light scattering, 8-anilino-1-naphthalene sulfonate fluorescence, and electron microscopy, and revealed that V210K PrP assembles into a non-fibrillar β-rich oligomer. Thus, the α-to-β conversion can be induced by introduction of a charged residue into the hydrophobic core, which provide novel insight into the structural dynamics of PrP.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

A novel ADCK4 mutation in a Chinese family with ADCK4-Associated glomerulopathy

Highlights: • ADCK4 is located on human chromosome 19q13.2 and encodes the ADCK4 protein, which interacts with members of the CoQ10 biosynthesis pathway. • Mutations in the ADCK4 gene can cause CoQ10 deficiency and mitochondrial nephropathy (ADCK4-associated glomerulopathy, ADCK4-GN). • ADCK4-GN mainly manifests as steroid resistant nephrotic syndrome clinically and focal segmental glomerulosclerosis pathologically. • The C-terminal portion in ADCK4 is important and indispensable. The upstream nonsense/frameshift mutations should be considered deleterious. • CoQ10 treatment may reduce proteinuria and postpone ADCK4-GN progression. AarF domain-containing kinase 4 (ADCK4)-associated glomerulopathy (ADCK4-GN) is an inherited mitochondrial nephropathy caused by mutations in the ADCK4 gene. Herein, we report a case of ADCK4-GN. The patient, a 14-year-old Chinese male, presented with asymptomatic proteinuria and steroid resistance. A renal biopsy showed focal segmental glomerulosclerosis (FSGS) and dysmorphic mitochondria in podocytes. Coenzyme Q10 treatment was partially effective. No adverse events were observed. Next generation and Sanger sequencing analyses revealed compound heterozygous mutations (c.625C > G, p.D209H and c.918G > T, p.C306X). Both inherited mutations are located in the highly conserved ABC1 domain. The unreported nonsense mutation causes a loss of 197 amino acids from the C-terminal portion of ADCK4, suggesting a deleterious effect of the truncating mutation by abolishing ADCK4 function. In conclusion, we identified a novel ABC1 domain-localized pathogenic mutation responsible for ADCK4-GN, further supporting the importance of the C-terminal portion of ADCK4. Next generation sequencing facilitated the early diagnosis. CoQ{sub 10} treatment may reduce proteinuria and postpone ADCK4-GN progression.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Inhibition of cGAS-STING-TBK1 signaling pathway by DP96R of ASFV China 2018/1

Highlights: • DP96R is an inhibitor of cGAS-triggered type I IFNs induction and NF-κB activation. • DP96R inhibits the phosphorylation of TBK1 and TBK1-mediated antiviral responses. • The C-terminal domain of DP96R is responsible for its inhibitory effects. African swine fever virus (ASFV) is a highly pathogenic large DNA virus that causes African swine fever (ASF) in domestic pigs and European wild boars with mortality rate up to 100%. The DP96R gene of ASFV encodes one of the viral virulence factors, yet its action mechanism remains unknown. In this study, we report that DP96R of ASFV China 2018/1 strain subverts type I IFN production in cGAS sensing pathway. DP96R inhibited the cGAS/STING, and TBK1 but not IRF3-5D mediated IFN-β and ISRE promoters activation. Furthermore, DP96R selectively blocked the activation of NF-κB promoter induced by cGAS/STING, TBK1, and IKKβ, but not by overexpression of p65. Moreover, DP96R inhibited phosphorylation of TBK1 stimulated by cGAS/STING activation, and TBK1-induced antiviral response. Finally, truncated mutation analysis demonstrated that the region spanning amino acids 30 to 96 of DP96R was responsible for the inhibitory activity. To our knowledge, this is for the first time that DP96R of ASFV China 2018/1 is reported to negatively regulate type I IFN expression and NF-κB signaling by inhibiting both TBK1 and IKKβ, which plays an important role in virus immune evasion.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Rapamycin alleviated pulmonary injury induced by fat embolism syndrome in rats

Fat embolism syndrome (FES) is a serious complication after trauma, surgery and fat emulsion input and can lead to serious pulmonary injury. Autophagy controls the cell survival and homeostasis by removing the mis-folded proteins and damaged organelles as well as intracellular pathogens through a lysosomal degradation pathway. Increasing research documented that autophagy was wildly involved in variety of human diseases and had huge therapeutic potential. However, the role and mechanism of autophagy in FES remains largely unknown. The rat model of FES was established by tail vein injection with fat and was assessed by Wet-to-Dry (W/D) ratio analysis, hematoxylin-eosin (HE) analysis, staining Oil red staining analysis and qPCR analysis. Western blots were employed to detect the expression of autophagy markers. The changes of pulmonary injury were observed after premedication of rapamycin (an autophagy activator). The alveolar structural damage, red free fat substances in the blood vessels of lung, increased the lung ratio, and the up-regulated MPO expression and activity were showed in the FES models. The expressions of autophagy markers were decreased and meanwhile, apoptosis markers were increased in the FES model. Rapamycin restored the expression of autophagy markers and inhibited the apoptosis and further, resulting in the improvement of the pulmonary injury. Thus, our study demonstrated that autophagy was inhibited and apoptosis was promoted in FES and further Rapamycin alleviated the pulmonary damage in FES via restoring the autophagy and inhibiting the apoptosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Active immunization using hand-push emulsification method increases the operator's risk of transcutaneous immunization

Highlights: • Researchers have the right to be told the relevant risks of immunological experiments. • Susceptible individuals to allergic diseases are suggested to be more careful when they perform immunological experiments. Setting up an animal model by using active immunization methods is a common means of studying immune-related diseases or producing antibodies with high titer and high activities. However, the security during the process of pathogen emulsification remains unclear. In a physical examination, we unexpectedly noticed high levels of angiotensin II type 1 receptor autoantibody (AT1-AA) specific to the immunizing antigen in the sera of some researchers who had participated in setting up active immunization animal models, and we were puzzled about the cause of AT1-AA production. In this study, we intended to investigate whether the emulsified antigen was the source of infection in these researchers, and if so, how to prevent it from occurring. AT1-AA was detected by advanced ELISA method. The participants presented higher levels of AT1-AA compared with non-participants of the same laboratory. This phenomenon remained that some factors during the process of rat model establishment may contribute to AT1-AA production. Animal and glove penetration studies indicated the emulsified antigen infection was attributed to neither aerosol or fur touch nor penetrating through gloves. However, AT1-AA level was largely decreased in the participants after they used an automatic emulsification device. Because of the strong permeability of the adjuvant, we speculated that emulsified antigen might get access to the unprotected skin of the participants accidentally during the immunization process. These results demonstrated that accidental contacts of emulsified antigens may infect researchers during the process of traditional hand-push emulsification, resulting in high specific autoantibody levels, which can be prevented by using appropriate tools.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Syk and JNK signaling pathways are involved in inflammasome activation in macrophages infected with Streptococcus pneumoniae

Highlights: • Syk- and JNK-dependent ASC oligomerization is crucial for inflammasome assembling during S. pneumoniae infection. • PLY participates in phosphorylation and activation of Syk and JNK in S. pneumoniae-infected macrophages. • Syk may be involved in JNK phosphorylation in S. pneumoniae infection. Streptococcus pneumoniae is a pathogen of significant clinical importance worldwide that can cause severe invasive diseases, such as pneumonia, otitis media and meningitis. Inflammsomes has been reported to participate in host defense against S. pneumoniae infection. S. pneumoniae could induce the assembly of the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3)/absent in melanoma 2 (AIM2) inflammasome, which mediates the activation of caspase-1 and the subsequent maturation of Interleukin-1β (IL-1β). However, the precise signals that activate inflammasomes during pneumococcal infection remain to be fully elucidated. In the present study, primary mouse macrophages were selected as a cell model, and the effects of kinases on inflammasome activity induced by S. pneumoniae infection were examined by ELISA and western blotting after pretreatment with a kinase inhibitor. Here, we show that Syk and JNK signaling are required for S. pneumoniae-induced activation of the inflammasome. Inhibitors of Syk and JNK almost abolished the oligomerization of apoptosis-associated speck-like protein containing a caspase-activating and recruitment domain (ASC) and subsequent caspase-1 activation and IL-1β secretion. Moreover, pneumolysin (PLY) participated in this process and was critical for Syk/JNK activation. These results suggested that the Syk/JNK signaling pathway may play a vital role in the inflammasome activation and modulate host immune responses against S. pneumoniae.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

SmpB down-regulates proton-motive force for the persister tolerance to aminoglycosides in Aeromonas veronii

Highlights: • The smpB deletion exhibited a higher susceptibility to aminoglycosides in A. veronii. • The expression level of SmpB was enhanced by gentamicin challenge. • The effect of SmpB on persistence formation was eliminated by PMF inhibition. • The smpB deletion downregulated proton-motive force-related metabolic genes. Bacterial persisters comprise a small fraction of phenotypically heterogeneous variants with transient capability for survival when exposed to high concentrations of antibiotic. In aquatic pathogenic bacteria Aeromonas veronii, Small Protein B (SmpB), the core factor of trans-translation system, was identified as a new persistence-related gene. The SmpB deletion exhibited a higher susceptibility and lower persister cell formation under aminoglycosides antibiotics pressure compared with wild type. The transcriptional and translational activities of smpB gene were significantly enhanced by the gentamicin challenge in exponential phase, but not changed in stationary phase. The transcriptomic analysis revealed that the smpB deletion stimulated the production of proton-motive force (PMF). The cell survival induced by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) further verified that SmpB variation affected the quantities of PMF. Taken together, these results uncovered a novel mechanism of persister formation mediated by SmpB under aminoglycosides treatments.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Thioredoxin-interacting protein-derived peptide (TN13) inhibits LPS-induced inflammation by inhibiting p38 MAPK signaling

Highlights: • TAT-TN13 suppresses p38 MAPK activity. • TAT-TN13 inhibits LPS-induced activation of macrophages. • TAT-TN13 downregulates NF-κB and AP-1 transcriptional activities. • TAT-TN13 inhibits LPS-induced inflammation in vitro and in vivo. Inflammation comprises an innate immune response, and is mainly induced by macrophages to protect the host from pathogens and mechanical injuries. The p38 mitogen-activated protein kinase (MAPK) pathway is a key regulator of inflammatory responses in macrophages. Here, we investigated the anti-inflammatory effects of thioredoxin-interacting protein-derived peptide (TN13) in macrophages in vitro and in vivo. Human immunodeficiency virus (HIV) trans-activator protein (TAT)-conjugated TN13 (TAT-TN13) was found to penetrate RAW 264.7 cells and decrease p38 MAPK activation in a dose-dependent manner. We also showed that TAT-TN13 could significantly inhibit lipopolysaccharide (LPS)-induced expression of macrophage activation-related receptors including CD80, CD86, and MHC II, as well as the transcriptional activation of nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) in RAW 264.7 cells and primary mouse splenic macrophages. Furthermore, TAT-TN13 decreased the LPS-induced production of proinflammatory cytokines and mediators such as tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), nitric oxide (NO), inducible NO synthase (iNOS), and cyclooxygenase 2 (COX-2) in RAW 264.7 cells and mice. These results indicate that TAT-TN13 can inhibit macrophage-derived inflammation by inhibiting p38 MAPK activity and might represent a potential novel drug for the treatment of inflammation-related diseases.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

A Trichomonas vaginalis C2-XYPPX-repeat protein with a structured C2 domain displaying dampened flexibility upon binding calcium

C2 domains are ubiquitous membrane-binding modules of ∼130 residues in eukaryotes that are often associated with proteins involved in membrane trafficking and lipid modification. The genome of Trichomonas vaginalis, the most common, non-viral, sexually transmitted human pathogen, encodes eight genes that contain a N-terminal C2 module linked to a XYPPX-repeat domain of more than four XYPPX repeats (C2-XYPPX). While the function of the XYPPX-repeat domain remains unknown, its multiple association with C2 domains in T. vaginalis suggests it is important. Here, the C2 domain from one of these C2-XYPPX-repeat proteins, Tv-C2-1, was structurally and physically characterized using X-ray crystallography and NMR spectroscopy. The crystal structure for Tv-C2-1 shows that this domain shares a fold common to all C2 domains, a compact Greek-key motif composed of eight anti-parallel β-strands in the type-2 topology. An NMR chemical shift perturbation study with Ca 2+ showed that Tv-C2-1 bound two Ca 2+ atoms primarily via two loops (loop-1 and loop-3) on the predicted calcium binding face of the protein with K d s of 58.0 ± 0.1 μM and 232 ± 6 μM. Estimations of the overall rotational correlation time, τ c , in the apo (11.1 ns) and Ca 2+ -bound (9.2 ns) state suggests the protein becomes more compact upon Ca 2+ binding, consistent with a decrease in dynamics in loop-3 and marginally in loop-1 suggested by amide 15 N heteronuclear steady-state { 1 H}- 15 N NOEs. Showing Tv-C2-1 binds calcium and adopts a compact Greek-key motif structure, two primary features of C2 domains, suggests understanding the function of the XYPPX-repeat domain may be warranted.

NMR spectroscopy↗
DOE OSTI2022

Tolerance to allelopathic inhibition by free fatty acids in five biofuel candidate microalgae strains

Contaminating organisms (grazers, pathogens, competitors) and self-inhibition by algae-produced allelopathic chemicals are two issues that may limit the productivity of algal cultivation for bioproducts. One potential solution is to identify algal strains that are not affected by allelopathic inhibition even while undesirable organisms are suppressed. Here we used two experiments to test how sensitivity to allelopathy varies across algae. In the first experiment, we tested the sensitivity of five biofuel candidate green algae strains to two allelopathic compounds (i.e., free fatty acids) and found that the degree of inhibition depends strongly on both the species and specific compound. In the second experiment, we exposed one alga (Chlorella) to the sterile-filtered medium of each species, and found that the concentration of free fatty acids released into the media predicted Chlorella’s growth response. This provides a better understanding of how the production of, and sensitivity to, allelopathic compounds determines algal productivity.

09 BIOMASS FUELS↗
DOE OSTI2017

Draft genome sequence of Chryseobacterium limigenitum SUR2 T (LMG 28734 T ) isolated from dehydrated sludge

The type strain SUR2 of the novel species Chryseobacterium limigenitum was isolated from a dehydrated sludge of the municipal sewage treatment plant in Dogoše near Maribor in Slovenia. The draft genome, with 60 contigs, 4,697,725 bp, 34.4% of G+C content, was obtained using the Illumina HiSeq 2500-1 platform. Joint Genome Institute Microbial Genome Annotation Pipeline (MGAP v.4) has identified 4322 protein-coding sequences including resistance genes against arsenic and other heavy metals. In addition, a subclass B3 metallo-β-lactamase, which confers resistance to penicillins, cephalosporins and carbapenems, was also present in the genome. The genome sequence provides important information regarding bioremediation potential and pathogenic properties of this newly identified species.

59 BASIC BIOLOGICAL SCIENCES↗