Displaying publications 61 - 80 of 1086 in total

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  1. Dynamics of polyhydroxyalkanoate accumulation in aerobic granules during the growth-disintegration cycle
    Gobi K, Vadivelu VM
    Bioresour Technol, 2015 Nov;196:731-5.
    PMID: 26235884 DOI: 10.1016/j.biortech.2015.07.083
    The polyhydroxyalkanoate (PHA) accumulation dynamics in aerobic granules that undergo the growth-disintegration cycle were investigated. Four sequencing batch reactors (SBR) were inoculated with aerobic granules at different stages of development (different sizes). Different sizes of aerobic granules showed varying PHA contents. Thus, further study was conducted to investigate the diffusion of substrate and oxygen on PHA accumulation using various organic loading rates (OLR) and aeration rates (AR). An increase in OLR from 0.91 to 3.64kg COD/m(3)day increased the PHA content from 0.66 to 0.87g PHA/g CDW. Meanwhile, an AR increase from 1 to 4L/min only accelerated the maximum PHA accumulation without affecting the PHA content. However, the PHA composition only changes with AR, while the hydroxyvalerate (HV) content increased at a higher AR.
    Matched MeSH terms: Oxygen
  2. Speciation patterns of heavy metals in tropical estuarine anoxic and oxidized sediments by different sequential extraction schemes
    Ngiam LS, Lim PE
    Sci Total Environ, 2001 Jul 25;275(1-3):53-61.
    PMID: 11482403
    The speciation patterns of Cu, Cd, Zn, Pb, Fe and Mn in sediment samples under anoxic and oxidized conditions were investigated using three-stage, four-stage and five-stage sequential extraction schemes. All the extraction schemes identify the non-residual metal among three basic operationally-defined host fractions, namely, exchangeable, reducible and organic/sulfide bound. The anoxic sediment samples were found to have been oxidized during the extraction stage for the reducible fraction under the three-stage and four-stage schemes and the moderately reducible fraction under the five-stage scheme despite the maintenance of an oxygen-free environment. This artifact has resulted in an over-representation of the reducible fraction and an under-representation of the organic/sulfide fraction in the heavy metal speciation patterns of anoxic sediment samples. For Cd, Zn and Pb which had > 70% associated with the acid volatile sulfide in the organic/sulfide fraction, this artifact has resulted in the observation of a decrease in the reducible fraction and, in some cases, an increase in the organic/sulfide fraction upon oxidation of the anoxic sediment samples.
    Matched MeSH terms: Oxygen
  3. Fulltext Gaseous oxygen (GOX) system upgrade for mitigation to process safety risk of brownfield unit
    Toh, Jia Lin, Siti Aslina Hussain
    Journal of Occupational Safety and Health, 2018;15(2):47-56.
    MyJurnal
    Company A is a brownfield refinery that had been in service for over 25 years and has its own system to generate GOX for its needed utility usage. Noting of the hazards of GOX and in consideration of an aged refinery, this research is of the intent to evaluate the risk of GOX in the aspect of personnel and process safety; and to provide recommendation or mitigations planning with regards to Company A’s existing hardware through Bow Tie review. The analysis was done taking into consideration the data compiled as well as the inherited Process Safety Assessment (PSA) findings of Company A that served as secondary data to this research. It was observed that Company A personnel are well versed with the risk and hazards of GOX system and through the plant rejuvenation and material upgrade works, the hazards were mitigated to a lower risk within the risk matrix. The implementation and upgrade works had served to add more barriers to the left side of the bow tie as well as ensuring that the aged complex is well equipped with needed safeguarding strategies (from inherent safer design, passive & active safeguarding and procedural controls) to avoid the occurrence of potential oxygen fire or explosion incident.
    Matched MeSH terms: Oxygen
  4. Fulltext Acute Metabolic Changes with Thigh-Positioned Wearable Resistances during Submaximal Running in Endurance-Trained Runners
    Field AP, Gill N, Macadam P, Plews D
    Sports (Basel), 2019 Aug 01;7(8).
    PMID: 31375020 DOI: 10.3390/sports7080187
    The aim of this study was to determine the acute metabolic effects of different magnitudes of wearable resistance (WR) attached to the thigh during submaximal running. Twenty endurance-trained runners (40.8 ± 8.2 years, 1.77 ± 0.7 m, 75.4 ± 9.2 kg) completed six submaximal eight-minute running trials unloaded and with WRs of 1%, 2%, 3%, 4% and 5% body mass (BM), in a random order. The use of a WR resulted in a 1.6 ± 0.6% increase in oxygen consumption (VO2) for every 1% BM of additional load. Inferential based analysis found that the loading of ≥3% BM was needed to elicit any substantial responses in VO2, with an increase that was likely to be moderate in scale (effect size (ES) ± 90% confidential interval (CI): 0.24 ± 0.07). Using heart rate data, a training load score was extrapolated to quantify the amount of internal stress. For every 1% BM of WR, there is an extra 0.17 ± 0.06 estimated increase in training load. A WR ≥3% of BM was needed to elicit substantial responses in lactate production, with an increase which was very likely to be large in scale (ES ± 90% CI: 0.41 ± 0.18). A thigh-positioned WR provides a running-specific overload with loads ≥3% BM, resulting in substantial changes in metabolic responses.
    Matched MeSH terms: Oxygen Consumption
  5. Haldane-Andrews substrate inhibition kinetics for pilot scale thermophilic anaerobic degradation of sugarcane vinasse
    Chai A, Wong YS, Ong SA, Aminah Lutpi N, Sam ST, Kee WC, et al.
    Bioresour Technol, 2021 Sep;336:125319.
    PMID: 34049168 DOI: 10.1016/j.biortech.2021.125319
    A pilot scale anaerobic degradation of sugarcane vinasse was carried out at various hydraulic retention time (HRT) in the Anaerobic Suspended Growth Closed Bioreactor (ASGCB) under thermophilic temperature. The performance and kinetics were evaluated through the Haldane-Andrews model to investigate the substrate inhibition potential of sugarcane vinasse. All parameters show great performance between HRT 35 and 25 days: chemical oxygen demand (COD) reduction efficiency (81.6 to 86.8%), volatile fatty acids (VFA) reduction efficiency (92.4 to 98.5%), maximum methane yield (70%) and maximum biogas production (19.35 L/day). Furthermore, steady state values from various HRT were obtained in the kinetic evaluation for: rXmax (1.20 /day), Ks (19.95 gCOD/L), Ki (7.00 gCOD/L) and [Formula: see text] (0.33 LCH4/gCOD reduction). This study shows that anaerobic degradation of sugarcane vinasse through ASGCB could perform well at high HRT and provides a low degree of substrate inhibition as compared to existing studies from literature.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  6. An experimental investigation on phytoremediation performance of water lettuce (Pistia stratiotes L.) for pollutants removal from paper mill effluent
    Singh J, Kumar V, Kumar P, Kumar P, Yadav KK, Cabral-Pinto MMS, et al.
    Water Environ Res, 2021 Sep;93(9):1543-1553.
    PMID: 33565675 DOI: 10.1002/wer.1536
    The present study describes the phytoremediation performance of water lettuce (Pistia stratiotes L.) for physicochemical pollutants elimination from paper mill effluent (PME). For this, pot (glass aquarium) experiments were conducted using 0% (BWW: borewell water), 25%, 50%, 75%, and 100% treatments of PME under natural day/light regime. Results of the experiments showed that the highest removal of pH (10.75%), electrical conductivity (EC: 63.82%), total dissolved solids (TDS: 71.20%) biological oxygen demand (BOD: 85.03%), chemical oxygen demand (COD: 80.46%), total Kjeldahl's nitrogen (TKN: 93.03%), phosphorus (P: 85.56%), sodium (Na: 91.89%), potassium (K: 84.04%), calcium (Ca: 84.75%), and magnesium (Mg: 83.62%), most probable number (MPN: 77.63%), and standard plate count (SPC: 74.43%) was noted in 75% treatment of PME after treatment by P. stratiotes. PCA showed the best vector length for TKN, Na, and Ca. The maximum plant growth parameters including, total fresh biomass (81.30 ± 0.28 g), chlorophyll content (3.67 ± 0.05 mg g-1  f.wt), and relative growth rate (0.0051 gg-1  d-1 ) was also measured in 75% PME treatment after phytoremediation experiments. The findings of this study make useful insight into the biological management of PME through plant-based pollutant eradication while leftover biomass may be used as a feedstock for low-cost bioenergy production. PRACTITIONER POINTS: Biological treatment of paper mill effluent using water lettuce is presented. Best reduction of physicochemical and microbiological pollutants was attained in 75% treatment. Maximum production of chlorophyll, plant biomass, and highest growth rate was also observed in 75% treatment.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  7. Fulltext Targeting energy metabolism to eliminate cancer cells
    Shahruzaman SH, Fakurazi S, Maniam S
    Cancer Manag Res, 2018;10:2325-2335.
    PMID: 30104901 DOI: 10.2147/CMAR.S167424
    Adaptive metabolic responses toward a low oxygen environment are essential to maintain rapid proliferation and are relevant for tumorigenesis. Reprogramming of core metabolism in tumors confers a selective growth advantage such as the ability to evade apoptosis and/or enhance cell proliferation and promotes tumor growth and progression. One of the mechanisms that contributes to tumor growth is the impairment of cancer cell metabolism. In this review, we outline the small-molecule inhibitors identified over the past decade in targeting cancer cell metabolism and the usage of some of these molecules in clinical trials.
    Matched MeSH terms: Oxygen
  8. Engineering surface oxygen defects on tungsten oxide to boost photocatalytic oxygen evolution from water splitting
    Chew YH, Tang JY, Tan LJ, Choi BWJ, Tan LL, Chai SP
    Chem Commun (Camb), 2019 May 28;55(44):6265-6268.
    PMID: 31086906 DOI: 10.1039/c9cc01449g
    The engineering of surface oxygen vacancies (OVs) in WO3 was primitively done using a facile solvothermal method. The photocatalytic activities of the as-prepared samples were studied by evaluating their performances in the photocatalytic OER. The best sample (W-3) yielded 57.6 μmol of O2 in 6 h under the illumination of simulated sunlight.
    Matched MeSH terms: Oxygen
  9. Spatial and temporal variations of water quality and trophic status in Bukit Merah Reservoir, Perak
    Mohd Shafiq Zakeyuddin, Amir Shah Ruddin Md Sah, Mohd Syaiful Mohammad, Nurul Fazlinda Mohd Fadzil, Zarul Hazrin Hashim, Wan Maznah Wan Omar
    Sains Malaysiana, 2016;45:853-863.
    A study of spatial and temporal variations on water quality and trophic status was conducted twice a month from December
    2012 to January 2014 in four sampling stations at Bukit Merah Reservoir (BMR). The concentration of dissolved oxygen
    (DO), water temperature, conductivity, total dissolved solids (TDS), total phosphorous (TP), PO4
    -
    , NO2
    -
    , NO3
    -
    , NH4
    + and
    net primary productivity had significant differences temporally (p<0.05) except for pH, total suspended solids (TSS)
    and chlorophyll-a. Based on correlation analysis, the amount of rainfall and rain days has negatively correlated with
    secchi depth and chlorophyll-a (p<0.01). The water level has significantly decreased the value of the temperature, pH,
    conductivity, TP and NO2
    -
    but it has positive correlation with NO3
    -
    and NH4
    +. Discharged from Sungai Kurau increased
    the value of conductivity, TSS, TP and NO2
    -
    as a result from runoff and erosion, thus decreasing the secchi depth values,
    NO3
    -
    and NH4
    +. The water quality of BMR is classified in Class II and TSI indicates that the BMR has an intermediate level
    of productivity (mesotrophic) and meets the objective of this reservoir which was to provide water for paddy irrigation.
    Matched MeSH terms: Oxygen
  10. Variations of southern south china sea characteristics near Pahang
    Nur Hidayah Roseli, Mohd Fadzil Mohd Akhir
    Sains Malaysiana, 2014;43:1389-1396.
    Oceanographic cruises in Pahang water in October 2003 and April 2004, monsoon transition months, produce data on water characteristics. The temperature in both months showed higher values in nearshore compared to the offshore stations. The nearshore salinity in both months is lower than offshore stations. Comparatively, there were smaller differences in temperature and salinity in October than in April, with very little variation between nearshore and offshore stations. T-S diagram showed significant differences between October and April water characteristics. According to the water characteristic observations, the temperature and salinity in October was lower than in April, while dissolved oxygen was higher than in April. The lower temperature and salinity taken during the sampling time in October suggested that during this time, the study area already received the influences of strong winds due to upcoming monsoon. The warmer and saltier water obtained in April showed that during this time, the study area was influenced by southwest monsoon. Winds related to rainfall were observed to have impact to the dynamics of water characteristics during both months.
    Matched MeSH terms: Oxygen
  11. Optimization of the humic acid separation and coagulation with natural starch by RSM for the removal of COD and colour from stabilized leachate
    Ahmed Z, Yusoff MS, Kamal NHM, Aziz HA
    Waste Manag Res, 2021 Nov;39(11):1396-1405.
    PMID: 33928820 DOI: 10.1177/0734242X211012775
    The removal of concentrated colour (around 5039 Pt-Co) and chemical oxygen demand (COD; around 4142 mg L-1) from matured landfill leachate through a novel combination of humic acid extraction and coagulation with natural oil palm trunk starch (OPTS) was investigated in this study. Central composite design from response surface methodology of Design Expert-10 software executed the experimental design to correlate experimental factors with desired responses. Analysis of variance developed the quadratic model for four factors (e.g. coagulant dosage, slow mixing speed and time and centrifugation duration) and two responses (% removal of colour, COD). The model confirmed the highest colour (84.96%) and COD (48.84%) removal with a desirability function of 0.836 at the optimum condition of 1.68 g L-1 coagulant dose, 19.11 rpm slow mixing speed, 16.43 minutes for mixing time and 35.75 minutes for centrifugation duration. Better results of correlation coefficient (R2 = 0.98 and 0.96) and predicted R2 (0.94 and 0.84) indicates the model significance. Electron microscopic images display the amalgamation of flocs through bridging. Fourier transforms infrared spectra confirmed the existence of selected organic groups in OPTS, which eventually signifies the applied method.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  12. Helmet continuous positive airway pressure vs. high flow nasal cannula oxygen in acute cardiogenic pulmonary oedema: a randomized controlled trial
    Osman A, Via G, Sallehuddin RM, Ahmad AH, Fei SK, Azil A, et al.
    Eur Heart J Acute Cardiovasc Care, 2021 Dec 18;10(10):1103-1111.
    PMID: 34632507 DOI: 10.1093/ehjacc/zuab078
    AIMS : Non-invasive ventilation represents an established treatment for acute cardiogenic pulmonary oedema (ACPO) although no data regarding the best ventilatory strategy are available. We aimed to compare the effectiveness of helmet CPAP (hCPAP) and high flow nasal cannula (HFNC) in the early treatment of ACPO.

    METHODS AND RESULTS : Single-centre randomized controlled trial of patients admitted to the emergency department due to ACPO with hypoxemia and dyspnoea on face mask oxygen therapy. Patients were randomly assigned with a 1:1 ratio to receive hCPAP or HFNC and FiO2 set to achieve an arterial oxygen saturation >94%. The primary outcome was a reduction in respiratory rate; secondary outcomes included changes in heart rate, PaO2/FiO2 ratio, Heart rate, Acidosis, Consciousness, Oxygenation, and Respiratory rate (HACOR) score, Dyspnoea Scale, and intubation rate. Data were collected before hCPAP/HFNC placement and after 1 h of treatment. Amongst 188 patients randomized, hCPAP was more effective than HFNC in reducing respiratory rate [-12 (95% CI; 11-13) vs. -9 (95% CI; 8-10), P 

    Matched MeSH terms: Oxygen
  13. Optimization of mixing ratio, shaking speed, contact time, and pH on reduction of Chemical Oxygen Demand (COD) and Ammoniacal Nitrogen (NH3-N) in leachate treatment
    Daud Z, Detho A, Rosli MA, Awang H, Ridzuan MBB, Tajarudin HA
    J Air Waste Manag Assoc, 2022 01;72(1):24-33.
    PMID: 33320054 DOI: 10.1080/10962247.2020.1862362
    When the inevitable generation of waste is considered as hazardous to health, damaging ecosystem to our environment, it is important to develop an innovative technologies to remediate pollutant sources for the safety and environmental protection. The development of adsorption technique for the reduction of extremely effective pollutants in this regard. Green mussel and zeolite mixing media were investigated for the reduction of the concentration of organic constituents (COD) and ammoniacal nitrogen from leachate. The leachate treatability was analyzed under various stages of treatment parameter, namely mixing ratio, shaking speed, contact time, and pH. Both adsorbent were sieve values in between 2.00-3.35 mm particle size. The optimum pH, shaking speed, contact time, and mixing ratio were determined. Leachate samples were collected from influent untreated detention pond at Simpang Renggam landfill site in Johor, Malaysia. The result of leachate characterization properties revealed that non-biodegradability leachate with higher concentrations of COD (1829 mg/L), ammoniacal nitrogen (406.68 mg/L) and biodegradability value (0.08) respectively. The optimal reduction condition of COD and ammoniacal nitrogen was obtained at 200 rpm shaken speed, 120 minute shaken time, optimum green mussel and zeolite mix ratio was 2.0:2.0, and pH 7. The isothermic study of adsorption shows that Langmuir is best suited for experimental results in terms of Freundlich model. The mixing media also provided promising results to treating leachate. This would be greatly applicable in conventionally minimizing zeolite use and thereby lowering the operating cost of leachate treatment.Implications: The concentration of organic constituents (COD) and ammoniacal nitrogen in stabilized landfill leachate have significant strong influences of human health and environmental. The combination of mixing media green mussel and zeolite adsorbent COD and ammoniacal nitrogen reduction efficiency from leachate. This would be greatly applicable in future research era as well as conventionally minimizing high cost materials like zeolite use and thereby lowering the operating cost of leachate treatment.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  14. Review on COD and ammoniacal nitrogen removal from landfill leachate using low-cost adsorbent
    Detho A, Daud Z, Rosli MA, Awang H, Ridzuan MBB
    J Air Waste Manag Assoc, 2022 01;72(1):10-23.
    PMID: 33689589 DOI: 10.1080/10962247.2021.1895366
    The rapid generation rate of solid waste is due to the increasing population and industrialization. Nowadays, solid waste has been a major concerning problem in handling and disposal thus adsorption treatment process has been introduced which is an effective and low-cost method in removing organic and inorganic compounds from leachates such as chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N). A most commonly adsorbent used for the removal of organic and inorganic compounds is activated carbon (AC), yet the main disadvantage is being too expensive in cost. Many researchers tried to use low-cost adsorbent waste materials, such as peat soil, limestone etc. This review article reveals a list of low-cost adsorbent and their capacity of adsorption for the removal of COD and NH3-N. Furthermore, the preparation of these low-cost adsorbents as well as their removal efficiencies, relative cost, and limitation are discussed. The most efficient, cost-effective, and environment-friendly adsorbent can be used for the removal of COD and NH3-N thus can be provided for commercial usage or water treatment plant.Implications: The concentration of organic constituents (COD) and ammonia nitrogen in stabilized landfill leachate has significant strong influences of human health and environmental. This review article shows the list of low-cost adsorbent (i.e., Activated carbon, Peat soil, Zeolite, Limestone, and cockle shell and their capacity of adsorption for the removal of COD and ammonia nitrogen. This would be greatly applicable in future research era as well as conventionally minimizing high-cost materials use and thereby lowering the operating cost of leachate wastewater treatment.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  15. Effect of famine-phase reduced aeration on polyhydroxyalkanoate accumulation in aerobic granules
    Vjayan T, Vadivelu VM
    Bioresour Technol, 2017 Dec;245(Pt A):970-976.
    PMID: 28946198 DOI: 10.1016/j.biortech.2017.09.038
    The effects of variable aeration in the famine period on polyhydroxyalkanoate (PHA) accumulation in aerobic granules were investigated. Results showed that regardless of the aeration rates used during famine period, all aerobic granules achieved a similar chemical oxygen demand removal and PHA content. The decrease in famine-period aeration rates accelerated the maximum PHA accumulation together with increase in granular size and settling ability. The PHA-accumulating microorganisms were found to have shifted closer to the surface of the granules when the aeration rate was reduced. Moreover, PHA compositional changes occurred, where the hydroxyvalerate content had increased with the reduction in aeration rate. Ultimately, the results indicate that the requirement of aeration for PHA accumulation in aerobic granules is highly insignificant in the famine phase. PHA production in aerobic granules under zero aeration in the famine period may result in an energy input reduction of up to 74%.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  16. Novel mesoporous MnCo2O4 nanorods as oxygen reduction catalyst at neutral pH in microbial fuel cells
    Kumar R, Singh L, Wahid ZA, Mahapatra DM, Liu H
    Bioresour Technol, 2018 Apr;254:1-6.
    PMID: 29413909 DOI: 10.1016/j.biortech.2018.01.053
    The aim of this work was to evaluate the comparative performance of hybrid metal oxide nanorods i.e. MnCo2O4 nanorods (MCON) and single metal oxide nanorods i.e. Co3O4 nanorods (CON) as oxygen reduction catalyst in microbial fuel cells (MFC). Compared to the single metal oxide, the hybrid MCON exhibited a higher BET surface area and provided additional positively charged ions, i.e., Co2+/Co3+ and Mn3+/Mn4+ on its surfaces, which increased the electro-conductivity of the cathode and improved the oxygen reduction kinetics significantly, achieved an io of 6.01 A/m2 that was 12.4% higher than CON. Moreover, the porous architecture of MCON facilitated the diffusion of electrolyte, reactants and electrons during the oxygen reduction, suggested by lower diffusion (Rd), activation (Ract) and ohmic resistance (Rohm) values. This enhanced oxygen reduction by MCON boosted the power generation in MFC, achieving a maximum power density of 587 mW/m2 that was ∼29% higher than CON.
    Matched MeSH terms: Oxygen
  17. Oxygen vacancy induced Bi2WO6 for the realization of photocatalytic CO2 reduction over the full solar spectrum: from the UV to the NIR region
    Kong XY, Choo YY, Chai SP, Soh AK, Mohamed AR
    Chem Commun (Camb), 2016 Dec 06;52(99):14242-14245.
    PMID: 27872917
    Photocatalytic CO2 reduction over the UV-Vis-NIR broad spectrum was realized for the first time. The presence of surface oxygen vacancy defects on Bi2WO6 resulted in significant photocatalytic enhancement over the pristine counterpart under UV and visible light irradiation. Meanwhile, the photocatalytic responsiveness of Bi2WO6-OV was successfully extended to the NIR region.
    Matched MeSH terms: Oxygen
  18. Fulltext Improving Water Quality Index Prediction Using Regression Learning Models
    Mohd Zebaral Hoque J, Ab Aziz NA, Alelyani S, Mohana M, Hosain M
    Int J Environ Res Public Health, 2022 Oct 21;19(20).
    PMID: 36294286 DOI: 10.3390/ijerph192013702
    Rivers are the main sources of freshwater supply for the world population. However, many economic activities contribute to river water pollution. River water quality can be monitored using various parameters, such as the pH level, dissolved oxygen, total suspended solids, and the chemical properties. Analyzing the trend and pattern of these parameters enables the prediction of the water quality so that proactive measures can be made by relevant authorities to prevent water pollution and predict the effectiveness of water restoration measures. Machine learning regression algorithms can be applied for this purpose. Here, eight machine learning regression techniques, including decision tree regression, linear regression, ridge, Lasso, support vector regression, random forest regression, extra tree regression, and the artificial neural network, are applied for the purpose of water quality index prediction. Historical data from Indian rivers are adopted for this study. The data refer to six water parameters. Twelve other features are then derived from the original six parameters. The performances of the models using different algorithms and sets of features are compared. The derived water quality rating scale features are identified to contribute toward the development of better regression models, while the linear regression and ridge offer the best performance. The best mean square error achieved is 0 and the correlation coefficient is 1.
    Matched MeSH terms: Oxygen
  19. PTEROBDELLA OCCIDENTALIS N. SP. (HIRUDINIDA: PISCICOLIDAE) FOR P. ABDITOVESICULATA (MOORE, 1952) FROM THE LONGJAW MUDSUCKER, GILLICHTHYS MIRABILIS, AND STAGHORN SCULPIN, LEPTOCOTTUS ARMATUS, AND OTHER FISHES IN THE EASTERN PACIFIC
    Goffredi SK, Appy RG, Burreson EM, Sakihara TS
    J Parasitol, 2023 Mar 01;109(2):135-144.
    PMID: 37103004 DOI: 10.1645/22-76
    Pterobdella occidentalis n. sp. (Hirudinida: Piscicolidae) is described from the longjaw mudsucker, Gillichthys mirabilis Cooper, 1864, and the staghorn sculpin, Leptocottus armatus Girard, 1854, in the eastern Pacific, and the diagnosis of Pterobdella abditovesiculata (Moore, 1952) from the 'o'opu 'akupa, Eleotris sandwicensis Vaillant and Sauvage, 1875, from Hawaii is amended. The morphology of both species conforms with the genus Pterobdella in possessing a spacious coelom, well-developed nephridial system, and 2 pairs of mycetomes. Originally described as Aestabdella abditovesiculata, P. occidentalis (present along the U.S. Pacific Coast), can be distinguished from most congeners by its metameric pigmentation pattern and diffuse pigmentation on the caudal sucker. Based on mitochondrial gene sequences, including cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit I (ND1), P. occidentalis forms a distinct polyphyletic clade with Pterobdella leiostomi from the western Atlantic. Based on COI, ND1, and the 18S rRNA genes, other leech species most closely related to P. occidentalis include Pterobdella arugamensis from Iran, Malaysia, and possibly Borneo, which likely represent distinct species, and Pterobdella abditovesiculata from Hawaii, one of only a few endemic fish parasites in Hawaii. Like P. abditovesiculata, P. arugamensis, and Petrobdella amara, P. occidentalis is often found in estuarine environments, frequently infecting hosts adapted to a wide range of salinity, temperature, and oxygen. The physiological plasticity of P. occidentalis and the longjaw mudsucker host, and the ease of raising P. occidentalis in the lab, make it an excellent candidate for the study of leech physiology, behavior, and possible bacterial symbionts.
    Matched MeSH terms: Oxygen
  20. Chemotherapy impairs ovarian function through excessive ROS-induced ferroptosis
    Zhang S, Liu Q, Chang M, Pan Y, Yahaya BH, Liu Y, et al.
    Cell Death Dis, 2023 May 24;14(5):340.
    PMID: 37225709 DOI: 10.1038/s41419-023-05859-0
    Chemotherapy was conventionally applied to kill cancer cells, but regrettably, they also induce damage to normal cells with high-proliferative capacity resulting in cardiotoxicity, nephrotoxicity, peripheral nerve toxicity, and ovarian toxicity. Of these, chemotherapy-induced ovarian damages mainly include but are not limited to decreased ovarian reserve, infertility, and ovarian atrophy. Therefore, exploring the underlying mechanism of chemotherapeutic drug-induced ovarian damage will pave the way to develop fertility-protective adjuvants for female patients during conventional cancer treatment. Herein, we firstly confirmed the abnormal gonadal hormone levels in patients who received chemotherapy and further found that conventional chemotherapeutic drugs (cyclophosphamide, CTX; paclitaxel, Tax; doxorubicin, Dox and cisplatin, Cis) treatment significantly decreased both the ovarian volume of mice and the number of primordial and antral follicles and accompanied with the ovarian fibrosis and reduced ovarian reserve in animal models. Subsequently, Tax, Dox, and Cis treatment can induce the apoptosis of ovarian granulosa cells (GCs), likely resulting from excessive reactive oxygen species (ROS) production-induced oxidative damage and impaired cellular anti-oxidative capacity. Thirdly, the following experiments demonstrated that Cis treatment could induce mitochondrial dysfunction through overproducing superoxide in GCs and trigger lipid peroxidation leading to ferroptosis, first reported in chemotherapy-induced ovarian damage. In addition, N-acetylcysteine (NAC) treatment could alleviate the Cis-induced toxicity in GCs by downregulating cellular ROS levels and enhancing the anti-oxidative capacity (promoting the expression of glutathione peroxidase, GPX4; nuclear factor erythroid 2-related factor 2, Nrf2 and heme oxygenase-1, HO-1). Our study confirmed the chemotherapy-induced chaotic hormonal state and ovarian damage in preclinical and clinical examination and indicated that chemotherapeutic drugs initiated ferroptosis in ovarian cells through excessive ROS-induced lipid peroxidation and mitochondrial dysfunction, leading to ovarian cell death. Consequently, developing fertility protectants from the chemotherapy-induced oxidative stress and ferroptosis perspective will ameliorate ovarian damage and further improve the life quality of cancer patients.
    Matched MeSH terms: Reactive Oxygen Species
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