The Journal of Real Estate Finance and Economics, 2007
This paper extends the extant literature in understanding the effects of equity and debt on delin... more This paper extends the extant literature in understanding the effects of equity and debt on delinquency and default by focusing on a variant of borrower equity where part of equity is "protected". The CPF scheme in Singapore stipulates that the refund of borrower's retirement funds utilized for property purchase prior to September 2002 takes priority over loan obligations. A decision to utilize CPF for property purchase actually increases ex post delinquency and default risk as it effectively reduces cash equity commitment. In particular, any erosion in house value that places protected equity at risk translates into potential wealth reduction or financial liability for the borrower. While loss aversion is evident for non-distressed sellers, the effect of equity losses for distressed borrowers is not as clear. Our research suggests that averting losses in committed equity may be a secondary consideration for borrower subject to income shocks, recognizing that delinquency and default are precursors to foreclosure. Interestingly, we find that the borrowers are strongly averse to incurring protected equity-induced wealth loss or financial liability. This study suggests that the first-lien "anomaly" associated with CPF refund may reduce delinquency and default risks for mortgage backed securities.
The microalga incorporated photobioreactor is a highly efficient biological system for converting... more The microalga incorporated photobioreactor is a highly efficient biological system for converting CO 2 into biomass. Using microalgal photobioreactor as CO 2 mitigation system is a practical approach for elimination of waste gas from the CO 2 emission. In this study, the marine microalga Chlorella sp. was cultured in a photobioreactor to assess biomass, lipid productivity and CO 2 reduction. We also determined the effects of cell density and CO 2 concentration on the growth of Chlorella sp. During an 8-day interval cultures in the semicontinuous cultivation, the specific growth rate and biomass of Chlorella sp. cultures in the conditions aerated 2-15% CO 2 were 0.58-0.66 d À1 and 0.76-0.87 g L À1 , respectively. At CO 2 concentrations of 2%, 5%, 10% and 15%, the rate of CO 2 reduction was 0.261, 0.316, 0.466 and 0.573 g h À1 , and efficiency of CO 2 removal was 58%, 27%, 20% and 16%, respectively. The efficiency of CO 2 removal was similar in the single photobioreactor and in the six-parallel photobioreactor. However, CO 2 reduction, production of biomass, and production of lipid were six times greater in the six-parallel photobioreactor than those in the single photobioreactor. In conclusion, inhibition of microalgal growth cultured in the system with high CO 2 (10-15%) aeration could be overcome via a high-density culture of microalgal inoculum that was adapted to 2% CO 2. Moreover, biological reduction of CO 2 in the established system could be parallely increased using the photobioreactor consisting of multiple units.
Background: Trichomonas vaginalis is an anaerobic parasitic protozoan of the human urogenital tra... more Background: Trichomonas vaginalis is an anaerobic parasitic protozoan of the human urogenital tract. Infection can cause vaginitis in women and urethritis in men. Accumulated reports indicated that exosomes released by protozoan parasites play important roles in transmitting information and substances between cells and mediating communication during host-parasite interactions in several parasitic infections. However, current knowledge on the protein contents in T. vaginalis exosome is mainly generated from three previous studies which used different T. vaginalis isolates as an experimental model. Therefore, whether T. vaginalis exosomes comprise a common set of proteins (core exosome proteome) is still unclear. Methods: To explore the core exosome proteome in T. vaginalis, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the contents of sucrose ultracentrifugation-enriched exosome isolated from six isolates. Results: Transmission electron microscopy (TEM...
Background Iron is an essential element for cellular functions, such as energy metabolism. Tricho... more Background Iron is an essential element for cellular functions, such as energy metabolism. Trichomonas vaginalis, a human urogenital tract pathogen, is capable of surviving in the environment without sufficient iron supplementation. Pseudocysts (cyst-like structures) are an environmentally tolerated stage of this parasite while encountering undesired conditions, such as iron deficiency. We demonstrated that iron deficiency induces more active glycolysis but a drastic downregulation of hydrogenosomal energy metabolic enzymes. Therefore, the metabolic direction of pyruvate is still controversial. Methods In the present work, we conducted an LC‒MS-based metabolomics analysis to obtain accurate insights into the enzymatic events of T. vaginalis under iron-depleted (ID) conditions. Results First, we showed the possible digestion of glycogen, cellulose polymerization, and accumulation of raffinose family oligosaccharides (RFOs). Second, a medium-chain fatty acid (MCFA) capric acid was ele...
Trichomonas vaginalis is a parasitic protist that infects the human urogenital tract. During the ... more Trichomonas vaginalis is a parasitic protist that infects the human urogenital tract. During the infection, trichomonads adhere to the host mucosa, acquire nutrients from the vaginal/prostate environment, and release small extracellular vesicles (sEVs) that contribute to the trichomonad adherence and modulate the host-parasite communication. Approximately 40-70% of T. vaginalis strains harbor a double-stranded RNA virus called Trichomonasvirus (TVV). Naked TVV particles have the potential to stimulate a proinflammatory response in human cells, however, the mode of TVV release from trichomonads to the environment is not clear. In this report, we showed for the first time that TVV particles are released from T. vaginalis cells within sEVs. The sEVs loaded with TVV stimulated a higher proinflammatory response of human HaCaT cells in comparison to sEVs from TVV negative parasites. Moreover, a comparison of T. vaginalis isogenic TVV plus and TVV minus clones revealed a significant impact of TVV infection on the sEV proteome and RNA cargo. Small EVs from TVV positive trichomonads contained 12 enriched and 8 unique proteins including membrane-associated BspA adhesine, and about a 2.5-fold increase in the content of small regulatory tsRNA. As T. vaginalis isolates are frequently infected with TVV, the release of TVV via sEVs to the environment represents an important factor with the potential to enhance inflammation-related pathogenesis during trichomoniasis.
Accumulated evidence suggests that the endosymbiotic Trichomonasvirus (TVV) may play a role in th... more Accumulated evidence suggests that the endosymbiotic Trichomonasvirus (TVV) may play a role in the pathogenesis and drug susceptibility of Trichomonas vaginalis. Several reports have shown that extracellular vesicles (EVs) released from TVV-positive (TVV+) trichomonads can modulate the immune response in human vaginal epithelial cells and animal models. These results prompted us to examine whether EVs released from TVV+ isolates contained TVV. We isolated small extracellular vesicles (sEVs) from six T. vaginalis isolates that were either TVV free (ATCC 50143), harbored a single (ATCC 30236, ATCC 30238, T1), two (ATCC PRA-98), or three TVV subspecies (ATCC 50148). The presence of TVV subspecies in the six isolates was observed using reverse transcription-polymerase chain reaction (RT-PCR). Transmission electron microscopy (TEM) confirmed the presence of cup-shaped sEVs with a size range from 30–150 nm. Trichomonas vaginalis tetraspanin (TvTSP1; TVAG_019180), the classical exosome mar...
Additional file 4: Figure S1. The mapping results of our previous next-generation RNA sequencing ... more Additional file 4: Figure S1. The mapping results of our previous next-generation RNA sequencing of TVAG_171090 and TVAG_171100. The short reads generated from the sequencing were mapped to the reference sequences (top of the figure, black), and the locations of individual reads are shown. Blue and light blue, unique paired-ended reads; green, forward single-ended reads; red, reverse single-ended reads; yellow, non-specific reads. Only the first 300 rows are shown in this figure.
Additional file 5: Figure S2. The effects of sodium nitrate treatment on ID T. vaginalis. a The S... more Additional file 5: Figure S2. The effects of sodium nitrate treatment on ID T. vaginalis. a The SNO proteomes of ID T. vaginalis treated with 25 and 50 mM of sodium nitrate and incubated for 6 h. b The viability of sodium nitrate-treated T. vaginalis after a 24 h incubation.
Additional file 3: Alignment S1. Sequence alignment of TvLDHs and TvMDHs. All of the TvLDHs and T... more Additional file 3: Alignment S1. Sequence alignment of TvLDHs and TvMDHs. All of the TvLDHs and TvMDHs were aligned as shown. The protein sequences containing leucine 91 (L91) are highlighted in red, and the accession numbers are presented in bold.
Additional file 2: Table S2. The expression patterns of glycolytic enzymes in T. vaginalis cultur... more Additional file 2: Table S2. The expression patterns of glycolytic enzymes in T. vaginalis cultured in iron-rich (IR) and -deficient (ID) conditions. The expression changes of all glycolytic enzymes in iron-deficient (ID) conditions relative to their expression in iron-rich control (IR) cells. The log 2-fold-changes (ID/IR) are shown; the background color indicates the upregulation (red) or downregulation (green) of each gene.
Background Iron plays essential roles in the pathogenesis and proliferation of Trichomonas vagina... more Background Iron plays essential roles in the pathogenesis and proliferation of Trichomonas vaginalis, the causative agent of the most prevalent nonviral human sexually transmitted infection. We previously demonstrated that under iron deficiency, the endogenous nitric oxide (NO) is accumulated and capable of regulating the survival of T. vaginalis. Herein, we aim to explore the influence of NO on the activity of the pyruvate-reducing enzyme lactate dehydrogenase in T. vaginalis (TvLDH).Methods Levels of lactate and pyruvate were detected for determining glycolysis activity in T. vaginalis under iron deficiency. Quantitative PCR was performed to determine the expression of TvLDH. S-nitrosylated (SNO) proteomics was conducted to identify the NO-modified proteins. The activities of glyceraldehyde-3-phosphate dehydrogenase (TvGAPDH) and TvLDH were measured after sodium nitrate treatment. The effects of protein nitrosylation on the production of cellular reducing power were examined by me...
Journal of Microbiology, Immunology and Infection, 2017
Background: Glucose is the major energy source that is converted to pyruvate for ATP generation i... more Background: Glucose is the major energy source that is converted to pyruvate for ATP generation in the trichomonad hydrogenosome. Under glucose restriction (GR), the regulation of amino acids metabolism is crucial for trichomonad growth and survival. RNAsequencing (RNA-seq) analysis has been used to identify differentially expressed genes in Trichomonas vaginalis under GR, leading to significant advances in understanding adaptive responses of amino acid metabolism to GR. However, the levels of amino acid metabolites modulated by GR are unknown in T. vaginalis. Methods: Herein, we describe a comprehensive metabolomic analysis of amino acid metabolites in the hydrogenosome using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry (LC-FT MS). The relative abundance of 17 hydrogenosomal amino acids was analyzed under GR and high-glucose (HG) conditions.
The growth and on-site bioremediation potential of an isolated thermal-and CO 2 -tolerant mutant ... more The growth and on-site bioremediation potential of an isolated thermal-and CO 2 -tolerant mutant strain, Chlorella sp. MTF-7, were investigated. The Chlorella sp. MTF-7 cultures were directly aerated with the flue gas generated from coke oven of a steel plant. The biomass concentration, growth rate and lipid content of Chlorella sp. MTF-7 cultured in an outdoor 50-L photobioreactor for 6 days was 2.87 g L À1 (with an initial culture biomass concentration of 0.75 g L À1 ), 0.52 g L À1 d À1 and 25.2%, respectively. By the operation with intermittent flue gas aeration in a double-set photobioreactor system, average efficiency of CO 2 removal from the flue gas could reach to 60%, and NO and SO 2 removal efficiency was maintained at approximately 70% and 50%, respectively. Our results demonstrate that flue gas from coke oven could be directly introduced into Chlorella sp. MTF-7 cultures to potentially produce algal biomass and efficiently capture CO 2 , NO and SO 2 from flue gas.
In this study, two thermal-tolerant mutants of Chlorella sp. MT-7 and MT-15, were isolated. In in... more In this study, two thermal-tolerant mutants of Chlorella sp. MT-7 and MT-15, were isolated. In indoor cultivation, specific growth rate (l, d À1) of the mutants were 1.4 to 1.8-fold at 25°C and 3.3 to 6.7-fold at 40°C higher than those of wild type. The carbon dioxide fixation rate of both microalgal mutants was also significantly higher than that of wild type. In outdoor closed cultivation, where the temperature of culture broth was 41 ± 1°C, the l of mutant strain MT-15 was 0.238 d À1 during an 8-day cultivation. Whereas, the growth of wild type was inhibited in the outdoor cultivation. Our results show that the isolated microalgal strains are adaptable to be applied in outdoor cultivation in subtropical zones.
In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of conce... more In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO 2 aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO 2 , the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L À1 d À1 with 2% CO 2 aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO 2 , the biomass and lipid productivity could reach to 0.372 and 0.084 g L À1 d À1 , respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12 d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L À1 d À1 in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L À1 d À1 in three-day replacement (three fifth broth was replaced every 3 d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO 2 and operated by one-day replacement.
A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxid... more A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxide (CO 2) into biomass. Using a microalgal photobioreactor as a CO 2 mitigation system is a practical approach to the problem of CO 2 emission from waste gas. In this study, a marine microalga, Chlorella sp. NCTU-2, was applied to assess biomass production and CO 2 removal. Three types of photobioreactors were designed and used: (i) without inner column (i.e. a bubble column), (ii) with a centric-tube column and (iii) with a porous centric-tube column. The specific growth rates (m) of the batch cultures in the bubble column, the centric-tube and the porous centric-tube photobioreactor were 0.180, 0.226 and 0.252 day À1 , respectively. The porous centrictube photobioreactor, operated in semicontinuous culture mode with 10% CO 2 aeration, was evaluated. The results show that the maximum biomass productivity was 0.61 g/L when one fourth of the culture broth was recovered every 2 days. The CO 2 removal efficiency was also determined by measuring the influent and effluent loads at different aeration rates and cell densities of Chlorella sp. NCTU-2. The results show that the CO 2 removal efficiency was related to biomass concentration and aeration rate. The maximum CO 2 removal efficiency of the Chlorella sp. NCTU-2 culture was 63% when the biomass was maintained at 5.15 g/L concentration and 0.125 vvm aeration (volume gas per volume broth per min; 10% CO 2 in the aeration gas) in the porous centric-tube photobioreactor.
Background: Rab5a GTPase plays important roles in intracellular transport and cell signaling. Res... more Background: Rab5a GTPase plays important roles in intracellular transport and cell signaling. Results: T-cell stimulation through the integrin LFA-1 or the chemokine receptor CXCR4 induces PKC⑀-dependent phosphorylation of Rab5a at Thr-7, which is crucial for cytoskeleton remodeling and cell migration. Conclusion: PKC⑀-Rab5a-Rac1 axis regulates T-cell motility. Significance: The study provides novel insights into the role of Rab5a in the adaptive immune response. Rab GTPases control membrane traffic and receptor-mediated endocytosis. Within this context, Rab5a plays an important role in the spatial regulation of intracellular transport and signal transduction processes. Here, we report a previously uncharacterized role for Rab5a in the regulation of T-cell motility. We show that Rab5a physically associates with protein kinase C⑀ (PKC⑀) in migrating T-cells. After stimulation of T-cells through the integrin LFA-1 or the chemokine receptor CXCR4, Rab5a is phosphorylated on an N-terminal Thr-7 site by PKC⑀. Both Rab5a and PKC⑀ dynamically interact at the centrosomal region of migrating cells, and PKC⑀-mediated phosphorylation on Thr-7 regulates Rab5a trafficking to the cell leading edge. Furthermore, we demonstrate that Rab5a Thr-7 phosphorylation is functionally necessary for Rac1 activation, actin rearrangement, and T-cell motility. We present a novel mechanism by which a PKC⑀-Rab5a-Rac1 axis regulates cytoskeleton remodeling and T-cell migration, both of which are central for the adaptive immune response. * This work was supported by grants from Science Foundation Ireland (to A. L.), Higher Education Authority of Ireland under PRTLI cycle 3 (to D. K.), Health Research Board of Ireland (to A. L.), Marie Curie MTKDCT-2005-029798 (to J. S.-Z.), NTU-MOE start-up grant (to N. K. V.), FWF Austrian Science Fund (P19505-B05) (to F. F. and G. B.), and the European Community Program SYBILLA under Grant HEALTH-F4-2008-201106 (to F. F. and G. B.). □ S This article contains supplemental Figs. 1 and 2 and Movies S1-S9.
The Journal of Real Estate Finance and Economics, 2007
This paper extends the extant literature in understanding the effects of equity and debt on delin... more This paper extends the extant literature in understanding the effects of equity and debt on delinquency and default by focusing on a variant of borrower equity where part of equity is "protected". The CPF scheme in Singapore stipulates that the refund of borrower's retirement funds utilized for property purchase prior to September 2002 takes priority over loan obligations. A decision to utilize CPF for property purchase actually increases ex post delinquency and default risk as it effectively reduces cash equity commitment. In particular, any erosion in house value that places protected equity at risk translates into potential wealth reduction or financial liability for the borrower. While loss aversion is evident for non-distressed sellers, the effect of equity losses for distressed borrowers is not as clear. Our research suggests that averting losses in committed equity may be a secondary consideration for borrower subject to income shocks, recognizing that delinquency and default are precursors to foreclosure. Interestingly, we find that the borrowers are strongly averse to incurring protected equity-induced wealth loss or financial liability. This study suggests that the first-lien "anomaly" associated with CPF refund may reduce delinquency and default risks for mortgage backed securities.
The microalga incorporated photobioreactor is a highly efficient biological system for converting... more The microalga incorporated photobioreactor is a highly efficient biological system for converting CO 2 into biomass. Using microalgal photobioreactor as CO 2 mitigation system is a practical approach for elimination of waste gas from the CO 2 emission. In this study, the marine microalga Chlorella sp. was cultured in a photobioreactor to assess biomass, lipid productivity and CO 2 reduction. We also determined the effects of cell density and CO 2 concentration on the growth of Chlorella sp. During an 8-day interval cultures in the semicontinuous cultivation, the specific growth rate and biomass of Chlorella sp. cultures in the conditions aerated 2-15% CO 2 were 0.58-0.66 d À1 and 0.76-0.87 g L À1 , respectively. At CO 2 concentrations of 2%, 5%, 10% and 15%, the rate of CO 2 reduction was 0.261, 0.316, 0.466 and 0.573 g h À1 , and efficiency of CO 2 removal was 58%, 27%, 20% and 16%, respectively. The efficiency of CO 2 removal was similar in the single photobioreactor and in the six-parallel photobioreactor. However, CO 2 reduction, production of biomass, and production of lipid were six times greater in the six-parallel photobioreactor than those in the single photobioreactor. In conclusion, inhibition of microalgal growth cultured in the system with high CO 2 (10-15%) aeration could be overcome via a high-density culture of microalgal inoculum that was adapted to 2% CO 2. Moreover, biological reduction of CO 2 in the established system could be parallely increased using the photobioreactor consisting of multiple units.
Background: Trichomonas vaginalis is an anaerobic parasitic protozoan of the human urogenital tra... more Background: Trichomonas vaginalis is an anaerobic parasitic protozoan of the human urogenital tract. Infection can cause vaginitis in women and urethritis in men. Accumulated reports indicated that exosomes released by protozoan parasites play important roles in transmitting information and substances between cells and mediating communication during host-parasite interactions in several parasitic infections. However, current knowledge on the protein contents in T. vaginalis exosome is mainly generated from three previous studies which used different T. vaginalis isolates as an experimental model. Therefore, whether T. vaginalis exosomes comprise a common set of proteins (core exosome proteome) is still unclear. Methods: To explore the core exosome proteome in T. vaginalis, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the contents of sucrose ultracentrifugation-enriched exosome isolated from six isolates. Results: Transmission electron microscopy (TEM...
Background Iron is an essential element for cellular functions, such as energy metabolism. Tricho... more Background Iron is an essential element for cellular functions, such as energy metabolism. Trichomonas vaginalis, a human urogenital tract pathogen, is capable of surviving in the environment without sufficient iron supplementation. Pseudocysts (cyst-like structures) are an environmentally tolerated stage of this parasite while encountering undesired conditions, such as iron deficiency. We demonstrated that iron deficiency induces more active glycolysis but a drastic downregulation of hydrogenosomal energy metabolic enzymes. Therefore, the metabolic direction of pyruvate is still controversial. Methods In the present work, we conducted an LC‒MS-based metabolomics analysis to obtain accurate insights into the enzymatic events of T. vaginalis under iron-depleted (ID) conditions. Results First, we showed the possible digestion of glycogen, cellulose polymerization, and accumulation of raffinose family oligosaccharides (RFOs). Second, a medium-chain fatty acid (MCFA) capric acid was ele...
Trichomonas vaginalis is a parasitic protist that infects the human urogenital tract. During the ... more Trichomonas vaginalis is a parasitic protist that infects the human urogenital tract. During the infection, trichomonads adhere to the host mucosa, acquire nutrients from the vaginal/prostate environment, and release small extracellular vesicles (sEVs) that contribute to the trichomonad adherence and modulate the host-parasite communication. Approximately 40-70% of T. vaginalis strains harbor a double-stranded RNA virus called Trichomonasvirus (TVV). Naked TVV particles have the potential to stimulate a proinflammatory response in human cells, however, the mode of TVV release from trichomonads to the environment is not clear. In this report, we showed for the first time that TVV particles are released from T. vaginalis cells within sEVs. The sEVs loaded with TVV stimulated a higher proinflammatory response of human HaCaT cells in comparison to sEVs from TVV negative parasites. Moreover, a comparison of T. vaginalis isogenic TVV plus and TVV minus clones revealed a significant impact of TVV infection on the sEV proteome and RNA cargo. Small EVs from TVV positive trichomonads contained 12 enriched and 8 unique proteins including membrane-associated BspA adhesine, and about a 2.5-fold increase in the content of small regulatory tsRNA. As T. vaginalis isolates are frequently infected with TVV, the release of TVV via sEVs to the environment represents an important factor with the potential to enhance inflammation-related pathogenesis during trichomoniasis.
Accumulated evidence suggests that the endosymbiotic Trichomonasvirus (TVV) may play a role in th... more Accumulated evidence suggests that the endosymbiotic Trichomonasvirus (TVV) may play a role in the pathogenesis and drug susceptibility of Trichomonas vaginalis. Several reports have shown that extracellular vesicles (EVs) released from TVV-positive (TVV+) trichomonads can modulate the immune response in human vaginal epithelial cells and animal models. These results prompted us to examine whether EVs released from TVV+ isolates contained TVV. We isolated small extracellular vesicles (sEVs) from six T. vaginalis isolates that were either TVV free (ATCC 50143), harbored a single (ATCC 30236, ATCC 30238, T1), two (ATCC PRA-98), or three TVV subspecies (ATCC 50148). The presence of TVV subspecies in the six isolates was observed using reverse transcription-polymerase chain reaction (RT-PCR). Transmission electron microscopy (TEM) confirmed the presence of cup-shaped sEVs with a size range from 30–150 nm. Trichomonas vaginalis tetraspanin (TvTSP1; TVAG_019180), the classical exosome mar...
Additional file 4: Figure S1. The mapping results of our previous next-generation RNA sequencing ... more Additional file 4: Figure S1. The mapping results of our previous next-generation RNA sequencing of TVAG_171090 and TVAG_171100. The short reads generated from the sequencing were mapped to the reference sequences (top of the figure, black), and the locations of individual reads are shown. Blue and light blue, unique paired-ended reads; green, forward single-ended reads; red, reverse single-ended reads; yellow, non-specific reads. Only the first 300 rows are shown in this figure.
Additional file 5: Figure S2. The effects of sodium nitrate treatment on ID T. vaginalis. a The S... more Additional file 5: Figure S2. The effects of sodium nitrate treatment on ID T. vaginalis. a The SNO proteomes of ID T. vaginalis treated with 25 and 50 mM of sodium nitrate and incubated for 6 h. b The viability of sodium nitrate-treated T. vaginalis after a 24 h incubation.
Additional file 3: Alignment S1. Sequence alignment of TvLDHs and TvMDHs. All of the TvLDHs and T... more Additional file 3: Alignment S1. Sequence alignment of TvLDHs and TvMDHs. All of the TvLDHs and TvMDHs were aligned as shown. The protein sequences containing leucine 91 (L91) are highlighted in red, and the accession numbers are presented in bold.
Additional file 2: Table S2. The expression patterns of glycolytic enzymes in T. vaginalis cultur... more Additional file 2: Table S2. The expression patterns of glycolytic enzymes in T. vaginalis cultured in iron-rich (IR) and -deficient (ID) conditions. The expression changes of all glycolytic enzymes in iron-deficient (ID) conditions relative to their expression in iron-rich control (IR) cells. The log 2-fold-changes (ID/IR) are shown; the background color indicates the upregulation (red) or downregulation (green) of each gene.
Background Iron plays essential roles in the pathogenesis and proliferation of Trichomonas vagina... more Background Iron plays essential roles in the pathogenesis and proliferation of Trichomonas vaginalis, the causative agent of the most prevalent nonviral human sexually transmitted infection. We previously demonstrated that under iron deficiency, the endogenous nitric oxide (NO) is accumulated and capable of regulating the survival of T. vaginalis. Herein, we aim to explore the influence of NO on the activity of the pyruvate-reducing enzyme lactate dehydrogenase in T. vaginalis (TvLDH).Methods Levels of lactate and pyruvate were detected for determining glycolysis activity in T. vaginalis under iron deficiency. Quantitative PCR was performed to determine the expression of TvLDH. S-nitrosylated (SNO) proteomics was conducted to identify the NO-modified proteins. The activities of glyceraldehyde-3-phosphate dehydrogenase (TvGAPDH) and TvLDH were measured after sodium nitrate treatment. The effects of protein nitrosylation on the production of cellular reducing power were examined by me...
Journal of Microbiology, Immunology and Infection, 2017
Background: Glucose is the major energy source that is converted to pyruvate for ATP generation i... more Background: Glucose is the major energy source that is converted to pyruvate for ATP generation in the trichomonad hydrogenosome. Under glucose restriction (GR), the regulation of amino acids metabolism is crucial for trichomonad growth and survival. RNAsequencing (RNA-seq) analysis has been used to identify differentially expressed genes in Trichomonas vaginalis under GR, leading to significant advances in understanding adaptive responses of amino acid metabolism to GR. However, the levels of amino acid metabolites modulated by GR are unknown in T. vaginalis. Methods: Herein, we describe a comprehensive metabolomic analysis of amino acid metabolites in the hydrogenosome using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry (LC-FT MS). The relative abundance of 17 hydrogenosomal amino acids was analyzed under GR and high-glucose (HG) conditions.
The growth and on-site bioremediation potential of an isolated thermal-and CO 2 -tolerant mutant ... more The growth and on-site bioremediation potential of an isolated thermal-and CO 2 -tolerant mutant strain, Chlorella sp. MTF-7, were investigated. The Chlorella sp. MTF-7 cultures were directly aerated with the flue gas generated from coke oven of a steel plant. The biomass concentration, growth rate and lipid content of Chlorella sp. MTF-7 cultured in an outdoor 50-L photobioreactor for 6 days was 2.87 g L À1 (with an initial culture biomass concentration of 0.75 g L À1 ), 0.52 g L À1 d À1 and 25.2%, respectively. By the operation with intermittent flue gas aeration in a double-set photobioreactor system, average efficiency of CO 2 removal from the flue gas could reach to 60%, and NO and SO 2 removal efficiency was maintained at approximately 70% and 50%, respectively. Our results demonstrate that flue gas from coke oven could be directly introduced into Chlorella sp. MTF-7 cultures to potentially produce algal biomass and efficiently capture CO 2 , NO and SO 2 from flue gas.
In this study, two thermal-tolerant mutants of Chlorella sp. MT-7 and MT-15, were isolated. In in... more In this study, two thermal-tolerant mutants of Chlorella sp. MT-7 and MT-15, were isolated. In indoor cultivation, specific growth rate (l, d À1) of the mutants were 1.4 to 1.8-fold at 25°C and 3.3 to 6.7-fold at 40°C higher than those of wild type. The carbon dioxide fixation rate of both microalgal mutants was also significantly higher than that of wild type. In outdoor closed cultivation, where the temperature of culture broth was 41 ± 1°C, the l of mutant strain MT-15 was 0.238 d À1 during an 8-day cultivation. Whereas, the growth of wild type was inhibited in the outdoor cultivation. Our results show that the isolated microalgal strains are adaptable to be applied in outdoor cultivation in subtropical zones.
In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of conce... more In order to produce microalgal lipids that can be transformed to biodiesel fuel, effects of concentration of CO 2 aeration on the biomass production and lipid accumulation of Nannochloropsis oculata in a semicontinuous culture were investigated in this study. Lipid content of N. oculata cells at different growth phases was also explored. The results showed that the lipid accumulation from logarithmic phase to stationary phase of N. oculata NCTU-3 was significantly increased from 30.8% to 50.4%. In the microalgal cultures aerated with 2%, 5%, 10% and 15% CO 2 , the maximal biomass and lipid productivity in the semicontinuous system were 0.480 and 0.142 g L À1 d À1 with 2% CO 2 aeration, respectively. Even the N. oculata NCTU-3 cultured in the semicontinuous system aerated with 15% CO 2 , the biomass and lipid productivity could reach to 0.372 and 0.084 g L À1 d À1 , respectively. In the comparison of productive efficiencies, the semicontinuous system was operated with two culture approaches over 12 d. The biomass and lipid productivity of N. oculata NCTU-3 were 0.497 and 0.151 g L À1 d À1 in one-day replacement (half broth was replaced each day), and were 0.296 and 0.121 g L À1 d À1 in three-day replacement (three fifth broth was replaced every 3 d), respectively. To optimize the condition for long-term biomass and lipid yield from N. oculata NCTU-3, this microalga was suggested to grow in the semicontinuous system aerated with 2% CO 2 and operated by one-day replacement.
A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxid... more A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxide (CO 2) into biomass. Using a microalgal photobioreactor as a CO 2 mitigation system is a practical approach to the problem of CO 2 emission from waste gas. In this study, a marine microalga, Chlorella sp. NCTU-2, was applied to assess biomass production and CO 2 removal. Three types of photobioreactors were designed and used: (i) without inner column (i.e. a bubble column), (ii) with a centric-tube column and (iii) with a porous centric-tube column. The specific growth rates (m) of the batch cultures in the bubble column, the centric-tube and the porous centric-tube photobioreactor were 0.180, 0.226 and 0.252 day À1 , respectively. The porous centrictube photobioreactor, operated in semicontinuous culture mode with 10% CO 2 aeration, was evaluated. The results show that the maximum biomass productivity was 0.61 g/L when one fourth of the culture broth was recovered every 2 days. The CO 2 removal efficiency was also determined by measuring the influent and effluent loads at different aeration rates and cell densities of Chlorella sp. NCTU-2. The results show that the CO 2 removal efficiency was related to biomass concentration and aeration rate. The maximum CO 2 removal efficiency of the Chlorella sp. NCTU-2 culture was 63% when the biomass was maintained at 5.15 g/L concentration and 0.125 vvm aeration (volume gas per volume broth per min; 10% CO 2 in the aeration gas) in the porous centric-tube photobioreactor.
Background: Rab5a GTPase plays important roles in intracellular transport and cell signaling. Res... more Background: Rab5a GTPase plays important roles in intracellular transport and cell signaling. Results: T-cell stimulation through the integrin LFA-1 or the chemokine receptor CXCR4 induces PKC⑀-dependent phosphorylation of Rab5a at Thr-7, which is crucial for cytoskeleton remodeling and cell migration. Conclusion: PKC⑀-Rab5a-Rac1 axis regulates T-cell motility. Significance: The study provides novel insights into the role of Rab5a in the adaptive immune response. Rab GTPases control membrane traffic and receptor-mediated endocytosis. Within this context, Rab5a plays an important role in the spatial regulation of intracellular transport and signal transduction processes. Here, we report a previously uncharacterized role for Rab5a in the regulation of T-cell motility. We show that Rab5a physically associates with protein kinase C⑀ (PKC⑀) in migrating T-cells. After stimulation of T-cells through the integrin LFA-1 or the chemokine receptor CXCR4, Rab5a is phosphorylated on an N-terminal Thr-7 site by PKC⑀. Both Rab5a and PKC⑀ dynamically interact at the centrosomal region of migrating cells, and PKC⑀-mediated phosphorylation on Thr-7 regulates Rab5a trafficking to the cell leading edge. Furthermore, we demonstrate that Rab5a Thr-7 phosphorylation is functionally necessary for Rac1 activation, actin rearrangement, and T-cell motility. We present a novel mechanism by which a PKC⑀-Rab5a-Rac1 axis regulates cytoskeleton remodeling and T-cell migration, both of which are central for the adaptive immune response. * This work was supported by grants from Science Foundation Ireland (to A. L.), Higher Education Authority of Ireland under PRTLI cycle 3 (to D. K.), Health Research Board of Ireland (to A. L.), Marie Curie MTKDCT-2005-029798 (to J. S.-Z.), NTU-MOE start-up grant (to N. K. V.), FWF Austrian Science Fund (P19505-B05) (to F. F. and G. B.), and the European Community Program SYBILLA under Grant HEALTH-F4-2008-201106 (to F. F. and G. B.). □ S This article contains supplemental Figs. 1 and 2 and Movies S1-S9.
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Papers by Seow Chin Ong