Validation of an adenosine triphosphate (ATP) model for 10-50 µm plankton.

A recent model demonstrated that the adenosine triphosphate (ATP) content of spherical aquatic organisms with a 10 to 50 µm diameter is between 0.16 and 19.9 pg cell-1. Here, the model is validated by comparing microscopy-based counts with ATP concentrations from a commercial ATP kit. The measured ATP content of both freshwater and marine organisms 10 to 50 µm size range falls in the 0.16 to 19.9 pg cell-1 model range. On average, freshwater organisms contain 0.33 pg ATP cell-1, have a spherical equivalent diameter (SED) of 13 µm, while marine organisms have 0.89 pg ATP cell-1 and a SED of 18 µm. In addition, their 13 to 18 µm size is within the 10 to 50 µm ballast water size range and in agreement with the 15 µm mean SED of a coastal plankton size-distribution model. This study concludes that the ATP-model is reliable, emphasizing the need for caution when converting three-dimensional biomass proxies into linear cell concentrations.

Examining the performance of three ballast water compliance monitoring devices for quantifying live organisms in both regulated size classes (≥50 µm and ≥10-<50 µm).

A number of ballast water compliance monitoring devices (CMDs) have been made commercially available to verify the efficacy of ballast water management systems by quantifying the living organisms for both plankton size classes (≥50 µm and ≥10-<50 µm). This study aimed to examine whether new CMDs can provide a reliable indication of compliance regarding Regulation D-2 and to evaluate their performance for indicative analysis of organisms by assessing their accuracy (comparison to microscopy) and precision (comparison within measurement). Challenge fresh water samples were collected in four locations of Lake Ontario, Canada, whereas marine challenge water samples were collected around the Bay of Fundy, New Brunswick, Canada. Ballast water samples were collected from ships visiting several ports across Canada. Overall, accuracy was higher (>80%) in estimating organisms from prepared-challenge water (Ballast Eye and BallastWISE) than from ballast water samples (>70%) (B-QUA only). The sensitivity ranged from 50 to 100% for the ≥50 µm organism size class, whereas for the ≥10-<50 µm organism size class, it was higher for freshwater samples (>75%) than for marine samples (>50%). The performance of CMDs should be assessed under real-world conditions for a better understanding and to improve their use.

First evaluation of ballast water management systems on operational ships for minimizing introductions of nonindigenous zooplankton.

Ballast water is a leading pathway for the global introduction of aquatic nonindigenous species. Most international ships are expected to install ballast water management systems (BWMS) by 2024 to treat ballast water before release. This study examines if ballast water discharges managed by BWMS are meeting standards for organisms ≥50 µm in minimum dimension (i.e., <10 organisms per m3; typically zooplankton). Representative samples of ballast water were collected from 29 ships (using 14 different BWMS) arriving to Canada during 2017-2018. Fourteen samples (48 %) had zooplankton concentrations clearly exceeding the standard (ranging from 18 to 3822 organisms per m3). Nonetheless, compared to earlier management strategies, BWMS appear to reduce the frequency of high-risk introduction events. BWMS filter mesh size was an important predictor of zooplankton concentration following treatment. Greater rates of compliance may be achieved as ship crews gain experience with operation and maintenance of BWMS.

Membrane Water Treatment for Drinking Water Production from an Industrial Effluent Used in the Manufacturing of Food Additives.

An integrated membrane process for treatment of effluents from food additive manufacturing was designed and evaluated on a laboratory scale. The principal focus was water recovery with the possibility of its reuse as potable water. The industrial effluent presented high content of dyes and salts. It was red in color and presented brine characteristics. The whole effluent was fed into the integrated process in continuous flow. The steps of the process are as follows: sedimentation (S), adsorption by activated carbon (AC), ion exchange using resins (IEXR), and reverse osmosis (RO) (S-AC-IEXR-RO). The effect of previous operations was evaluated by stress-rupture curves in packaged columns of AC and IEXR, membrane flux, and fouling dominance in RO. Fouling was evaluated by way of the Silt Density Index and membrane resistance examination during effluent treatment. The integrated membrane process provided reclaimed water with sufficiently high standards of quality for reuse as potable water. AC showed a high efficiency for color elimination, reaching its rupture point at 20 h and after 5L of effluent treatment. IEXR showed capacity for salt removal, providing 2.2-2.5 L of effluent treatment, reaching its rupture point at 11-15 h. As a result of these previous operations and operating conditions, the fouling of the RO membrane was alleviated, displaying high flux of water: 20-18 L/h/m2 and maintaining reversible fouling dominance at a feed flow rate of 0.5-0.7 L/h. The characteristics of the reclaimed water showed drinking water standards.

Assessing the performance of four indicative analysis devices for ballast water compliance monitoring, considering organisms in the size range ≥10 to <50 µm.

To minimize the global transfer of harmful aquatic organisms and pathogens, the International Maritime Organization (IMO) has introduced the standard in Regulation D-2 to limit the number of viable organisms in ballast water discharged by ships. To meet the standard, many ships are installing ballast water management systems. Concurrently, regulators are looking for indicative analysis devices able to assess compliance with Regulation D-2, producing rapid, accurate and reliable results while being easy to operate. The purpose of this research is to compare four indicative analysis devices against detailed microscopy for measuring the size class of organisms ≥10 to <50 µm in minimum dimension (e.g., phytoplankton, including autotrophs, heterotrophs or mixotrophs), using field and laboratory tests. Comparisons were conducted on (treated) ballast water discharge samples collected across Canada during three consecutive years (2017-2019). During seven tests in 2019, paired ballast water uptake samples were also obtained, facilitating measurements before and after treatment was applied. Indicative analysis devices also were challenged with natural environmental samples containing different organism abundance levels, ranging from low (nominally <10 cells mL-1) to high (nominally >150 cells mL-1) during laboratory tests. While the indicative analysis devices examined during this research produced numeric estimates having weak correlations with the standard reference method, categorical outcomes (above/below the D-2 standard) had high agreement (89% or better) when assessing ballast water samples, but lower agreement (67% or poorer) during laboratory tests. There was a relatively high rate of false negative results measured by all devices during laboratory tests. Results provided by indicative analysis devices had higher uncertainty when organism abundances in ballast samples are below and close to the D-2 standards.

Influence of oxygen on the vinyl acetate elimination pathway and microbial community structure of methanogenic sludge.

Methanogenic-aerobic coupled processes were used to biological degradation of vinyl acetate (VA) to provide evidence of oxygen role for their complete elimination from different angles. First, physiological characterization of a continuous methanogenic-aerobic reactor fed by VA and glucose (G) showed that by adding G, the VA got 100% hydrolyzed to acetate, and then, by adding 1 mg·L-1 ·d-1 of dissolved oxygen (DO), this acetate got methanized by 40% and aerobically mineralized by 60%. Second, batch assays in the presence and absence of sodium azide suggest that VA at different concentrations was eliminated by both anaerobic and aerobic metabolic pathways, because without azide and in the presence of 1 mg DO·L-1 increased methane and carbon dioxide formation rates at 80% and 75%, respectively. Finally, microbial population dynamics analysis of the reactor by DGGE-sequencing highlighted that Brevibacillus agri (aerobic) and Methanosarcina barkeri (anaerobic) were identified as responsible for VA elimination by up to 98.6%. PRACTITIONER POINTS: Vinyl acetate is removed by simultaneous methanation and aerobic respiration. Methanosarcina barkeri and Brevibacillus agri removed up to 99% of vinyl acetate. DO and VA have a selective effect on the metabolism and population dynamics.

Ballast Water Exchange Plus Treatment Lowers Species Invasion Rate in Freshwater Ecosystems.

The movement of ballast water by commercial shipping is a prominent pathway for aquatic invasions. Ships' ballast water management is now transitioning from open ocean exchange to a ballast water performance standard that will effectively require use of onboard treatment systems. Neither strategy is perfect, therefore, combined use of ballast water exchange plus treatment has been suggested to provide greatest protection of aquatic ecosystems. This study compared the performance of exchange plus treatment against treatment alone by modeling establishment rates of nonindigenous zooplankton introduced by ballast water across different habitat types (fresh, brackish, and marine) in Canada. Treatment was modeled under two efficacy scenarios (100% and 50% of ship trips) to consider the possibility that treatment may not always be successful. The model results indicate that exchange plus treatment will be more effective than treatment alone at reducing establishments when recipient ports are freshwater (58 140 vs 11 338 trips until ≥1 establishment occurs, respectively). Exchange plus treatment also serves as an important backup strategy if treatment systems are partially effective (50% of trips), primarily for freshwater recipient ecosystems (1442 versus 585 trips until ≥1 establishment occurs, respectively).

Hepatocyte growth factor enhances the clearance of a multidrug-resistant Mycobacterium tuberculosis strain by high doses of conventional chemotherapy, preserving liver function.

Tuberculosis (TB) is one of the deadliest infectious diseases in humankind history. Although, drug sensible TB is slowly decreasing, at present the rise of TB cases produced by multidrug-resistant (MDR) and extensively drug-resistant strains is a big challenge. Thus, looking for new therapeutic options against these MDR strains is mandatory. In the present work, we studied, in BALB/c mice infected with MDR strain, the therapeutic effect of supra-pharmacological doses of the conventional primary antibiotics rifampicin and isoniazid (administrated by gavage or intratracheal routes), in combination with recombinant human hepatocyte growth factor (HGF). This high dose of antibiotics administered for 3 months, overcome the resistant threshold of the MDR strain producing a significant reduction of pulmonary bacillary loads but induced liver damage, which was totally prevented by the administration of HGF. To address the long-term efficiency of this combined treatment, groups of animals after 1 month of treatment termination were immunosuppressed by glucocorticoid administration and, after 1 month, mice were euthanized, and the bacillary load was determined in lungs. In comparison with animals treated only with a high dose of antibiotics, animals that received the combined treatment showed significantly lower bacterial burdens. Thus, treatment of MDR-TB with very high doses of primary antibiotics particularly administrated by aerial route can produce a very good therapeutic effect, and its hepatic toxicity can be prevented by the administration of HGF, becoming in a new treatment modality for MDR-TB.

Cadmium exposure exacerbates hyperlipidemia in cholesterol-overloaded hepatocytes via autophagy dysregulation.

Metabolic factors are the major risk of non-alcoholic fatty liver disease, although other factors may contribute steatosis. Cadmium exposure produces histopathological and molecular changes in liver, which are consistent with steatosis. In the present study, we describe the effect of low cadmium acute treatment on hepatocytes obtained from mice fed with a high cholesterol diet. Our data suggest that hepatocytes with cholesterol overload promote an adaptive response against cadmium-induced acute toxicity by up-regulating anti-apoptotic proteins, managing ROS overproduction, increasing GSH synthesis and MT-II content to avoid protein oxidation. Cadmium treatment increases lipid content in cholesterol-fed mice hepatocytes because of an impaired autophagy process. Our data suggest an essential function of macroautophagy in the regulation of lipid storage induced by Cd on hepatocytes, that implies that alterations in this pathway may be a mechanism that aggravates hepatic steatosis.

Strategy to identify the causes and to solve a sludge granulation problem in methanogenic reactors: application to a full-scale plant treating cheese wastewater.

Granulation of biomass is at the basis of the operation of the most successful anaerobic systems (UASB, EGSB and IC reactors) applied worldwide for wastewater treatment. Despite of decades of studies of the biomass granulation process, it is still not fully understood and controlled. "Degranulation/lack of granulation" is a problem that occurs sometimes in anaerobic systems resulting often in heavy loss of biomass and poor treatment efficiencies or even complete reactor failure. Such a problem occurred in Mexico in two full-scale UASB reactors treating cheese wastewater. A close follow-up of the plant was performed to try to identify the factors responsible for the phenomenon. Basically, the list of possible causes to a granulation problem that were investigated can be classified amongst nutritional, i.e. related to wastewater composition (e.g. deficiency or excess of macronutrients or micronutrients, too high COD proportion due to proteins or volatile fatty acids, high ammonium, sulphate or fat concentrations), operational (excessive loading rate, sub- or over-optimal water upflow velocity) and structural (poor hydraulic design of the plant). Despite of an intensive search, the causes of the granulation problems could not be identified. The present case remains however an example of the strategy that must be followed to identify these causes and could be used as a guide for plant operators or consultants who are confronted with a similar situation independently of the type of wastewater. According to a large literature based on successful experiments at lab scale, an attempt to artificially granulate the industrial reactor biomass through the dosage of a cationic polymer was also tested but equally failed. Instead of promoting granulation, the dosage caused a heavy sludge flotation. This shows that the scaling of such a procedure from lab to real scale cannot be advised right away unless its operability at such a scale can be demonstrated.

Cholesterol overload in the liver aggravates oxidative stress-mediated DNA damage and accelerates hepatocarcinogenesis.

Primary liver cancers represent the second leading cause of cancer-related deaths worldwide. Diverse etiological factors include chronic viral hepatitis, aflatoxin and alcohol exposure as well as aberrant liver lipid overload. Cholesterol has been identified as a key inducer of metabolic impairment, oxidative stress and promoter of cellular dysfunction. The aim of this work was to address the oxidative stress-mediated DNA damage induced by cholesterol overload, and its role in the development of hepatocellular carcinoma. C57BL/6 male mice were fed with a high cholesterol diet, followed by a single dose of N-diethylnitrosamine (DEN, 10 µg/g, ip). Reactive oxygen species generation, DNA oxidation, antioxidant and DNA repair proteins were analyzed at different time points. Diet-induced cholesterol overload caused enhanced oxidative DNA damage in the liver and was associated with a decrease in key DNA repair genes as early as 7 days. Interestingly, we found a cell survival response, induced by cholesterol, judged by a decrement in Bax to Bcl2 ratio. Importantly, N-acetyl-cysteine supplementation significantly prevented DNA oxidation damage. Furthermore, at 8 months after DEN administration, tumor growth was significantly enhanced in mice under cholesterol diet in comparison to control animals. Together, these results suggest that cholesterol overload exerts an oxidative stress-mediated effects and promotes the development of liver cancer.

Combining Ballast Water Exchange and Treatment To Maximize Prevention of Species Introductions to Freshwater Ecosystems.

The most effective way to manage species transfers is to prevent their introduction via vector regulation. Soon, international ships will be required to meet numeric ballast discharge standards using ballast water treatment (BWT) systems, and ballast water exchange (BWE), currently required by several countries, will be phased out. However, there are concerns that BWT systems may not function reliably in fresh and/or turbid water. A land-based evaluation of simulated "BWE plus BWT" versus "BWT alone" demonstrated potential benefits of combining BWE with BWT for protection of freshwater ecosystems. We conducted ship-based testing to compare the efficacy of "BWE plus BWT" versus "BWT alone" on voyages starting with freshwater ballast. We tested the hypotheses that there is an additional effect of "BWE plus BWT" compared to "BWT alone" on the reduction of plankton, and that taxa remaining after "BWE plus BWT" will be marine (low risk for establishment at freshwater recipient ports). Our study found that BWE has significant additional effect on the reduction of plankton, and this effect increases with initial abundance. As per expectations, "BWT alone" tanks contained higher risk freshwater or euryhaline taxa at discharge, while "BWE plus BWT" tanks contained mostly lower risk marine taxa unlikely to survive in recipient freshwater ecosystems.

Relative invasion risk for plankton across marine and freshwater systems: examining efficacy of proposed international ballast water discharge standards.

Understanding the implications of different management strategies is necessary to identify best conservation trajectories for ecosystems exposed to anthropogenic stressors. For example, science-based risk assessments at large scales are needed to understand efficacy of different vector management approaches aimed at preventing biological invasions associated with commercial shipping. We conducted a landscape-scale analysis to examine the relative invasion risk of ballast water discharges among different shipping pathways (e.g., Transoceanic, Coastal or Domestic), ecosystems (e.g., freshwater, brackish and marine), and timescales (annual and per discharge event) under current and future management regimes. The arrival and survival potential of nonindigenous species (NIS) was estimated based on directional shipping networks and their associated propagule pressure, environmental similarity between donor-recipient ecosystems (based on salinity and temperature), and effects of current and future management strategies (i.e., ballast water exchange and treatment to meet proposed international biological discharge standards). Our findings show that current requirements for ballast water exchange effectively reduce invasion risk to freshwater ecosystems but are less protective of marine ecosystems because of greater environmental mismatch between source (oceanic) and recipient (freshwater) ecoregions. Future requirements for ballast water treatment are expected to reduce risk of zooplankton NIS introductions across ecosystem types but are expected to be less effective in reducing risk of phytoplankton NIS. This large-scale risk assessment across heterogeneous ecosystems represents a major step towards understanding the likelihood of invasion in relation to shipping networks, the relative efficacy of different invasion management regimes and seizing opportunities to reduce the ecological and economic implications of biological invasions.

Hepatocyte growth factor protects against isoniazid/rifampicin-induced oxidative liver damage.

The worldwide increment of multidrug- and extensively drug-resistant tuberculosis has emphasized the importance of looking for new options in therapeutics. Long-time usage or higher doses of isoniazid and rifampicin have been considered for the treatment of multidrug-resistant tuberculosis; however, the risk of liver failure is proportionally increased. Hepatocyte growth factor (HGF) is a multitask growth factor that stimulates both antiapoptotic and antioxidant responses that counteract the toxic effects of drug metabolism in the liver. The present work was focused to address the antioxidant and antiapoptotic effects of HGF on isoniazid- and rifampicin-induced hepatotoxicity. BALB/c mice were subjected to rifampicin (150mg/kg, intragavage [ig]) plus isoniazid (75mg/kg, ig) for 7 days. Increments in alanine aminotransferase activity, steatosis, apoptosis, and oxidative stress markers were found in animals. Recombinant HGF (iv) prevented all the harmful effects by increasing the activation of Erk1/2 and PKCδ signaling pathways and glutathione (GSH) synthesis. Furthermore, inhibition of endogenous HGF with anti-HGF antibody (iv) enhanced the isoniazid- and rifampicin-induced oxidative stress damage and decreased the GSH content, aggravating liver damage. In conclusion, HGF demonstrated to be a good protective factor against antituberculosis drug-induced hepatotoxicity and could be considered a good adjuvant factor for the use of high doses of or the reintroduction of these antituberculosis drugs.

Biodegradation of 2-chlorophenol (2CP) in an anaerobic sequencing batch reactor (ASBR).

The aim of this study is to contribute to the knowledge about anaerobic digestion of 2-chlorophenol (2CP) in an anaerobic sequencing batch reactor (ASBR). Two reactors were set up (ASBR(A) and ASBR(B)). The ASBR(A) was fed with 2-chlorophenol (28-196 mg 2CP-C/L) and no other exogenous electron donor. The ASBR(B) was fed with a mixture of 2CP (28-196 mg 2CP-C/L) and phenol (28-196 mg phenol-C/L) as an electron donor. The process evaluation was conducted by three means: first by substrate consumption efficiency (E(2CP)), second, by biogas yield (Y(biogas-C/2CP-C)) and third, by the specific consumption rates (q(2CP)) as response variables. The 2CP consumption efficiency (90 ± 0.4%) was not influenced by the increase in the concentrations tested. In both reactors ASBR(A) and ASBR(B), both concentration as well as speed increased. Concentration increased from 28 to 114 mg 2CP-C/L. The specific consumption rate (q(2CP)) values were fivefold higher. However, a decrease of 37% was observed at 140 mg 2CP-C/L and one of 72% at 196 mg 2CP-C/L. The biogas yields (0.80 ± 0.06) remained stable in both reactors. In both reactors the biogas yield decreased to 78 ± 3% at 196 mg 2CP-C/L. We might assume this decrease was due to the accumulation of VFA. Finally, poor sludge settleability was determined only in the SBR(B) reactor at 140 and 196 mg 2CP-C/L. An increase was observed in both SVI ≤ 140 ± 5 mL/g and over exopolymeric protein ≤120 mg EP/L.

Relationship between propagule pressure and colonization pressure in invasion ecology: a test with ships' ballast.

Increasing empirical evidence indicates the number of released individuals (i.e. propagule pressure) and number of released species (i.e. colonization pressure) are key determinants of the number of species that successfully invade new habitats. In view of these relationships, and the possibility that ships transport whole communities of organisms, we collected 333 ballast water and sediment samples to investigate the relationship between propagule and colonization pressure for a variety of diverse taxonomic groups (diatoms, dinoflagellates and invertebrates). We also reviewed the scientific literature to compare the number of species transported by ships to those reported in nature. Here, we show that even though ships transport nearly entire local communities, a strong relationship between propagule and colonization pressure exists only for dinoflagellates. Our study provides evidence that colonization pressure of invertebrates and diatoms may fluctuate widely irrespective of propagule pressure. We suggest that the lack of correspondence is explained by reduced uptake of invertebrates into the transport vector and the sensitivity of invertebrates and diatoms to selective pressures during transportation. Selection during transportation is initially evident through decreases in propagule pressure, followed by decreased colonization pressure in the most sensitive taxa.

The effects of hydraulic loading and NaCl concentrations on the regeneration of exhausted homoionic natural zeolite.

A study of the suitable operational conditions for the regeneration of exhausted homoionic natural zeolite with ammonium was carried out. Laboratory-scale columns using NaCl solutions with concentrations of 2 and 4 mol/L and hydraulic loadings of 4, 6 and 8 bed volumes per hour (BV/h) were assessed. For both NaCl concentrations studied, the hydraulic load of 6 BV/h showed the highest ammonia nitrogen output from the exhausted zeolite bed. Results showed that the hydraulic load (BV/h) had a greater influence on the regeneration efficiency than the concentration of the regenerating solution.

Multiple syntrophic interactions in a terephthalate-degrading methanogenic consortium.

Terephthalate (TA) is one of the top 50 chemicals produced worldwide. Its production results in a TA-containing wastewater that is treated by anaerobic processes through a poorly understood methanogenic syntrophy. Using metagenomics, we characterized the methanogenic consortium inside a hyper-mesophilic (that is, between mesophilic and thermophilic), TA-degrading bioreactor. We identified genes belonging to dominant Pelotomaculum species presumably involved in TA degradation through decarboxylation, dearomatization, and modified ß-oxidation to H(2)/CO(2) and acetate. These intermediates are converted to CH(4)/CO(2) by three novel hyper-mesophilic methanogens. Additional secondary syntrophic interactions were predicted in Thermotogae, Syntrophus and candidate phyla OP5 and WWE1 populations. The OP5 encodes genes capable of anaerobic autotrophic butyrate production and Thermotogae, Syntrophus and WWE1 have the genetic potential to oxidize butyrate to CO(2)/H(2) and acetate. These observations suggest that the TA-degrading consortium consists of additional syntrophic interactions beyond the standard H(2)-producing syntroph-methanogen partnership that may serve to improve community stability.

Obesity and metabolic risks in children.

BACKGROUND: We undertook this study to establish the prevalence of overweight, obesity, abdominal obesity, high blood pressure, and high glucose and triglyceride levels in school-age children from Mexico City, as well as to determine how overweight and obesity are related to the other risk factors. METHODS: The study was a cross-sectional survey comprised of 1819 children (6-13 years of age) attending six elementary schools. Gender, age, weight, height, waist circumference, blood pressure, and levels of triglycerides and glucose were registered. Percentiles were calculated according to American standards for BMI, height, waist circumference, and blood pressure. RESULTS: Compared to American references, mean percentiles for waist circumference and BMI were >50, and mean height percentiles were <50. Prevalence of overweight was 22.3 and 23.6% for boys and girls, respectively; obesity, 28 and 21.2%; abdominal obesity, 22.1 and 11.7%; high triglyceride levels, 11.3 and 15.4%; high blood pressure, 4.8 and 5.8%, respectively. Overweight, obesity, and abdominal obesity are associated with higher blood pressure and triglyceride levels (odds ratio>1.0, p<0.05). Percentiles for BMI, waist circumference, systolic blood pressure, and diastolic blood pressure also had significant correlations (r>0.2, p<0.001). CONCLUSIONS: This population of Mexican school-age children was shorter and heavier than their American standards. The prevalence of metabolic risks was similar to those reported in American adolescents in NHANES surveys.