The effect of store conditions on the rotting of apples, cv. Bramley's Seedling, by Nectria galligena

The log of the time interval between inoculation with Nectria galligena in October and the onset of rotting in apples held in air was proportional to the deficit between the temperature of incubation and 25°C, but temperature did not affect the rate of subsequent rot expansion. Rots expanded equally fast whether apples were held in dry or moist air. The quantity of rotted tissue obtained after incubating inoculated apples in atmospheres containing up to 12.5% CO₂ increased with increasing concentrations of CO₂ greater than 2.5%. The quantity of rotted tissue obtained in apples incubated in 10% CO₂ was three times as great as that obtained after incubation in air. The incidence of natural rots was lower in apples stored at 4% CO₂ than in those stored in air and rotting increased with increasing concentrations of CO₂ higher than 4%. Colonies of N. galligena grew faster on malt agar plates incubated in 5% CO₂ than in air, but growth was slower in 10% CO₂ than in air. The quantity of benzoic acid per mg hyphae accumulated in developing lesions was similarly related to the CO₂ concentrations up to 2.5% but decreased at higher concentrations, and the quantities found in apples stored in CO₂ concentrations >5.0% CO₂ were less than in those stored in air.     

Antilipolytic activity of viprostol, a transdermally active antihypertensive PGE2 analog

Viprostol, a novel prostaglandin E₂ congener, was assessed for antilipolytic activity in the spontaneously obese rat. In isolated epididymal adipocytes, viprostal exhibited a dose-dependent inhibition of catecholamine-stimulated lipolysis at concentrations ranging from 10 μM to 1 mM, but was ineffective at lower concentrations. Additionally, viprostal exhibited approximately 50% of the antilipolytic activity of naturally-occurring PGE₁ and PGE₂ at similar concentrations, but was as potent as PGF_2α. At 10 μM, viprostol inhibited maximum catecholamine-stimulated lipolysis by approximately 35% of the total, hormone-stimulated glycerol release. The results of these experiments indicate that viprostol exhibits antilipolytic activity , but is less potent than the naturally-occurring PGE's to which it is most closely related structurally.     

The effects of acute and chronic morphine treatment and of morphine withdrawal on rat brain in vivo

1. The effects of morphine, nalorphine, acetazolamide, and 10% CO₂ on brain metabolite concentrations of 24h-starved rats were studied. 2. A single dose of morphine (20mg/kg body wt.) caused an increase in brain glucose concentration (42%) and decreased concentrations of lactate (24%), pyruvate (29%), citrate (20%), α-oxoglutarate (16%), malate (14%) and creatine phosphate (10%) after 30min. No changes were found in adenine nucleotide concentrations. 3. The same dose of morphine increased arterial CO₂ from 5.07 to 7.60 kN/m² (38 to 57 Torr), decreased the pH from 7.41 to 7.31 and decreased O₂ from 14.1 to 10.8kN/m² (106 to 81 Torr) at 30min. 4. Rats injected with morphine three times daily (20mg/kg body wt.) for 2 weeks had no changes in brain metabolite concentrations or in blood gases 30min after their last injection. 5. Nalorphine (an antagonist of morphine) caused essentially no changes in brain metabolite concentrations in normal rats. When nalorphine (20mg/kg) was administered to rats previously treated with morphine three times daily for 2 weeks, there was an increase in brain glucose (100%), lactate (23%), pyruvate (18%) and citrate (10%) concentrations. 6. Acetazolamide (an inhibitor of carbonic anhydrase) and 10% CO₂ increased the arterial CO₂ from 4.79 to 6.78kN/m² (36 to 51 Torr) and from 5.32 to 10.8kN/m² (40 to 81 Torr) respectively. 7. Both acetazolamide and 10% CO₂ caused changes in brain metabolite concentrations similar to those for acutely administered morphine. Thus 10% CO₂ caused increased brain glucose concentration (123%) and decreased brain lactate (46%), pyruvate (34%), citrate (26%), α-oxoglutarate (33%), malate (45%) and creatine phosphate (7%) concentrations. No changes in adenine nucleotide concentrations were found. 8. The results indicate that the effect of morphine on brain metabolite concentrations may be accounted for by the increased [CO₂]. 9. These findings constitute a consistent pattern of metabolic changes after acute morphine administration, morphine addiction, and withdrawal from morphine addiction.     

Study of PM10, PM2.5, and PM1 levels in during dust storms and local air pollution events in urban and rural sites in Tehran

The aim of this study is to survey the PM₁₀, PM_2.5, and PM₁ concentrations in rural and urban areas in Tehran province during cold, warm and dust storm days from December 22, 2016 to June 5, 2017 using Grimm Model aerosol spectrometer. During the study period, daily PM₁₀, PM_2.5, and PM₁ concentrations ranged from 27.2 to 244.96, 8.4 to 77.9, and 6.5 to 56.8 μg/m³ in urban sites, and 22.8 to 286.4, 6 to 41.1, and 2.1 to 20.2 μg/m³ in rural parts, respectively. Particularly, both daily WHO limits for outdoor PM₁₀ (50.0 μg/m³) and PM_2.5 (25.0 μg/m³) exceeded in 95% and 83% of the outdoor measurements in winter and 82% and 58% in total sampled days in urban site, respectively. The 24-h average PM₁₀ and PM_2.5 concentrations also exceeded by 59% and 18% in winter and by 36% and 14% of all sampling days in rural site, respectively. During the dust storm, the 24-h average PM₁₀, PM_2.5, and PM₁ concentrations were, respectively 4.7, 2, and 1.96 times higher than those in urban site and 2, 1.7, and 1.3 times more than those in rural site in all sampled days.     

Assessment of grain quality in terms of functional group response to elevated [CO2], water,and nitrogen using a meta‐analysis: Grain protein,zinc, and iron under future climate

The increasing [CO₂] in the atmosphere increases crop productivity. However, grain quality of cereals and pulses are substantially decreased and consequently compromise human health. Meta‐analysis techniques were employed to investigate the effect of elevated [CO₂] (e[CO₂]) on protein, zinc (Zn), and iron (Fe) concentrations of major food crops (542 experimental observations from 135 studies) including wheat, rice, soybean, field peas, and corn considering different levels of water and nitrogen (N). Each crop, except soybean, had decreased protein, Zn, and Fe concentrations when grown at e[CO₂] concentration (≥550 μmol/mol) compared to ambient [CO₂] (a[CO₂]) concentration (≤380 μmol/mol). Grain protein, Zn, and Fe concentrations were reduced under e[CO₂]; however, the responses of protein, Zn, and Fe concentrations to e[CO₂] were modified by water stress and N. There was an increase in Fe concentration in soybean under medium N and wet conditions but nonsignificant. The reductions in protein concentrations for wheat and rice were ~5%–10%, and the reductions in Zn and Fe concentrations were ~3%–12%. For soybean, there was a small and nonsignificant increase of 0.37% in its protein concentration under medium N and dry water, while Zn and Fe concentrations were reduced by ~2%–5%. The protein concentration of field peas decreased by 1.7%, and the reductions in Zn and Fe concentrations were ~4%–10%. The reductions in protein, Zn, and Fe concentrations of corn were ~5%–10%. Bias in the dataset was assessed using a regression test and rank correlation. The analysis indicated that there are medium levels of bias within published meta‐analysis studies of crops responses to free‐air [CO₂] enrichment (FACE). However, the integration of the influence of reporting bias did not affect the significance or the direction of the [CO₂] effects.     

MEMBRANE THIAMINE TRTPHOSPHATASE FROM RAT BRAIN: INHIBITION BY ATP AND ADP

—The hydrolysis of ThTP by rat brain membrane-bound ThTPase is inhibited by nucleoside diphosphates and triphosphates. ATP and ADP are most effective, reducing hydrolysis by 50% at concentrations of 2 × 10^?5m and 7·5 × 10^?5m respectively. Nucleoside monophosphates and free nuclcosides as well as P_i have no effect on enzyme activity. ThMP and ThDP also fail to inhibit hydrolysis in concentrations up to 5 × 10^?3m . Non-hydrolysable methylene phosphate analogs of ATP and ADP were used in further kinetic studies with the ThTPase. The mechanism of inhibition by these analogs is shown to be of mixed non-competitive nature for both compounds. An observed K_i, of 4 × 10^?5m for the ATP analog adenosine-PPCP and 9 × 10^?5m for the ADP analog adenosine-PCP is calculated at pH 6·5. Formation of the true enzyme substrate, the [Mg²⁺. ThTP] complex, is not significantly affected by concentrations of analogs producing maximal (>95%) inhibition of enzyme activity. Likewise the relationships between pH and observed K_m and pH and V_max are not shifted by the presence of similar concentrations of inhibitor.     

Air quality modeling for health risk assessment of ambient PM10, PM2.5 and SO2 in Iran

In this study, we have estimated the number of total mortality (T-mortality), cardiovascular morbidity (CV-mortality), respiratory mortality (R-mortality), hospital admissions due to cardiovascular diseases (HA-CVD), respiratory diseases (HA-RD), chronic obstructive pulmonary diseases (COPD) and acute myocardial infarction (AMI) due to exposure to particulate matter less than 10 µm (PM₁₀), 2.5 µm (PM_2.5) and sulfur dioxide (SO₂) in western Iran in 2016. The World Health Organization (WHO) method was used to assess the mortality and morbidity among the exposed people. The results showed that about 3.9% CM (95% CI: 2.9–7.8%), 3.9% HA-RD (95% CI: 2.4–7.8%) and 4.4% HA-CVD (95% CI: 3.0–6.8%) for ambient PM₁₀ and about 7.3% TM (95% CI: 4.2–9.7%), 12.1% CM (95% CI: 3.5–14.6%) and 3.0% RM (95% CI: 0–6.3%) for PM_2.5 are respectively attributed to concentrations exceeding 10 µg/m³. Furthermore, 3.2% HA-COPD (95% CI: 0–5.04%) and 4.2% AMI (95% CI: 1.6–4.3%) can be attributed to SO₂ concentrations greater than 10 µg/m³, respectively. To reduce the adverse health effect of PM, health advices provided by health authorities should be given to general population especially vulnerable people such as people with chronic lung and heart pathologies, elderly and children during the dusty days.     

Enhancement of antibody production by the addition of Coenzyme-Q<Subscript>10</Subscript>

Recently, there has been a growing demand for therapeutic monoclonal antibodies (MAbs) on the global market. Because therapeutic MAbs are more expensive than low-molecular-weight drugs, there have been strong demands to lower their production costs. Therefore, efficient methods to minimize the cost of goods are currently active areas of research. We have screened several enhancers of specific MAb production rate (SPR) using a YB2/0 cell line and found that coenzyme-Q₁₀ (CoQ₁₀) is a promising enhancer candidate. CoQ₁₀ is well known as a strong antioxidant in the respiratory chain and is used for healthcare and other applications. Because CoQ₁₀ is negligibly water soluble, most studies are limited by low concentrations. We added CoQ₁₀ to a culture medium as dispersed nanoparticles at several concentrations (Q-Media) and conducted a fed-batch culture. Although the Q-Media had no effect on cumulative viable cell density, it enhanced SPR by 29%. In addition, the Q-Media had no effect on the binding or cytotoxic activity of MAbs. Q-Media also enhanced SPR with CHO and NS0 cell lines by 30%. These observations suggest that CoQ₁₀ serves as a powerful aid in the production of MAbs by enhancing SPR without changing the characteristics of cell growth, or adversely affecting the quality or biological activity of MAbs.     

16,16-Dimethyl PGE2 and fatty acids protect hepatocytes against CCl4-induced damage

Summary 16,16-Dimethyl PGE₂ (dmPGE₂) has previously been shown to protect the in vivo rat liver against CCl₄-induced damage. These studies were undertaken to determine if this protection could be demonstrated in vitro where factors of absorption, secretion, and blood flow are not present. Primary hepatocyte cultures were established by perfusing rat liver with collagenase. Hepatocytes were plated at a density of 2×10⁴ cells/cm, allowed 90 min to attach, then stabilized in L15 medium for 18 h. Hepatocytes were then challenged with CCl₄ with concomitant exposure to 10⁻⁹ to 10⁻⁵ M dmPGE₂, stearic acid, oleic acid, or ethanol vehicle (0.00001 to 0.1%). After 1 h, challenge was aspirated and cells were stained with 0.04% trypan blue to determine viability. Hepatocytes in the vehicle groups took up more trypan when exposed to CCl₄ than those treated with dmPGE₂, stearic acid, or oleic acid at concentrations of 10⁻⁹ to 10⁻⁷ M. At 0.1% ethanol vehicle protected as well as all other treatments. Protection against CCl₄ by dmPGE₂, stearic, and oleic acids as well as high concentrations of ethanol may occur by altering the metabolism of CCl₄.     

Atmospheric conditions required for the growth ofGaleola septentrionalis seedlings

The seedling of an achlorophyllous orchid,Galeola septentrionalis, requires for its early growth anomalous atmospheric conditions appropriate to each process of development. The most favorable atmosphere for the enlargement of protocorm consists of 10% O₂, 6% CO₂ and 84% N₂ at a pressure of 1.4 kg/cm². Tolerable ranges of atmospheric pressure, concentrations of O₂ and CO₂ were 1.1–2.0 kg/cm², 5–12% and 2–10%, respectively. Such a range for culture temperatures was 20–26 C. Subsequent development of the seedlings was little influenced by atmospheric pressure (1.0–1.8 kg/cm²) and concentration of CO₂ (0–8%), but influenced by O₂ concentration. Optimum and tolerable concentrations of O₂ were 10–15% and 5–19.7%, respectively. These atmospheres are discussed hypothetically as the conditions required to pass an inevitable process specific to the epigenetic ontogeny of scobiform (sawdusty) seeds.     

Plasma coenzyme Q10 concentrations are not decreased in male patients with coronary atherosclerosis

Coenzyme Q₁₀ (CoQ₁₀) is an important mitochondrial electron transfer component and has been postulated to function as a powerful antioxidant protecting LDL from oxidative damage. It could thus reduce the risk of cardiovascular disease. Thus far, beneficial effects of supplementation with CoQ₁₀ have been reported. To study the relation between unsupplemented concentrations of plasma CoQ₁₀ and coronary atherosclerosis, we performed a case-control study among 71 male cases with angiographically documented severe coronary atherosclerosis and 69 healthy male controls free from symptomatic cardiovascular disease and without atherosclerotic plaques in the carotid artery.

Plasma CoQ₁₀ concentrations (mean ± SE) were 0.86 ± 0.04 vs. 0.83 ± 0.04 μmol/l for cases and controls, respectively. The CoQ₁₀/LDL-cholesterol ratio (μmol/mmol) was slightly lower in cases than in controls (0.22 ± 0.01 vs. 0.26 ± 0.03). Differences in CoQ₁₀ concentrations and CoQ₁₀/LDL-cholesterol ratio did not reach significance. The odds ratios (95% confidence interval) for the risk of coronary atherosclerosis calculated per μmol/l increase of CoQ₁₀ was 1.12 (0.28–4.43) after adjustment for age, smoking habits, total cholesterol and diastolic blood pressure.

We conclude that an unsupplemented plasma CoQ₁₀ concentration is not related to risk of coronary atherosclerosis.     

Biochemical changes in human cervical connective tissue after intracervical application of prostaglandin E2

Cervical biopsies were taken during the first trimester from primigravidae and plurigravidae at different time points after intracervical application of prostaglandin E₂-gel. Collagenase activity was determined by a highly specific technique using native, triple helical collagen as substrate. Elastase-_α1-proteinase-inhibitor complex (elastase) was measured by a commercially available assay, and glycosaminoglycan (GAG) analyses were performed as described by Greiling et al. (5, 6). The maximum activity of collagenase was found 2 hours after PGE₂ application in plurigravidae and 4 hours after application in primigravidae. Elastase activity rose nearly 7-fold to maximum values 4 hours after PGE₂ application. The total GAG concentrations and the dermatan sulfate concentrations increased by approximately 10 %, while the hyaluronic acid concentrations were found to be elevated significantly by nearly 50 % in the PGE₂-primed cervices.We conclude that a time-dependent enzymatic collagen degradation by collagenases and other proteinases and an increase in hyaluronic acid concentrations are the significant biochemical events underlying PG-induced cervical ripening.     

Benthic sediment influence on dissolved phosphorus concentrations in a headwater stream

Phosphate interacts with inorganic sediment particles through sorption reactions in streams. Collectively, this phosphorus (P) buffering mechanism can be an important determinant of soluble reactive P (SRP) concentrations. If sorption reactions control SRP concentrations in a stream, then differences in sediment characteristics may cause spatial differences in SRP concentrations. This prediction was tested by examining sediment-buffering characteristics and spatial variation in SRP among reaches with distinct sediment composition (i.e., fine versus coarse particles) in two tributaries of Boulder Creek, a headwater stream in central Wisconsin. SRP concentrations were significantly lower and algal available P and P sorption capacity were significantly higher in the reach dominated by fine sediments. Although fine particles such as sand had the greatest P sorption capacity, no retention could be attributed to biotic processes, whereas over 50% of P retention in coarse particles such as gravel could be linked to biotic uptake. Equilibrium P concentration (EPC₀) assays from different sediment fractions also indicate that biotic uptake is relatively unimportant in sand particles (EPC_live 10 μg/L: EPC_killed 10 μg/L) but very important in gravel or larger particles (EPC_live 10 μg/L: EPC_killed 80 μg/L). Thus, sediment influence on stream water P concentrations can shift predictably from abiotic sorption in reaches with fine particles to biotic retention in areas dominated by coarse sediments. Consequently, changes in sediment composition due to natural or anthropogenic disturbance have the potential to alter the type and strength of sediment-associated processes determining ambient stream P concentrations.     

Effects of cooling and freezing on the motility of Ostrea edulis (L., 1758) spermatozoa after thawing

The aim of this work was to evaluate the effects of temperature, cryoprotectant agents and freezing curves on sperm motility of Ostrea edulis. All phases of cryopreservation were studied (evaluation of semen motility pattern, choice of cryoprotectants and freezing rates) to restore after thawing the motility characteristics distinctive of fresh semen.To assess the temperature effects on sperm motility, semen was activated using four different temperatures (25, 18, 10 and 3 °C). Sperm aliquots were maintained inactive at these temperatures for 1 and 3 h, then activated with FSW at same temperature of conservation. Sperm was activated and incubated to 3 °C with dimethylsulfoxide (Me₂SO), ethylene glycol (EG), 1–2 propylene glycol (PG) (5%, 7%, 10% and 15% final concentrations), glycerol (GlOH; 5%, 10% and 15% final concentrations) and methanol (MetOH; 4% and 10% final concentrations) for 10, 20 and 30 min. A first evaluation of freezing rates was made by testing four freezing curves: −1, −3, −6 and −10 °C/min. Then, an optimization was made by testing four freezing curves: −2.5, −3.0, −3.5 and −4 °C/min.The selected temperature for short term conservation has been 3 °C, because only this temperature has allowed good sperm motility conservation after 3 h of dry-storage; this is a time sufficient to conduct cryopreservation procedures. The sperm showed a particular sensitivity to GlOH and PG to all tested concentrations and to 15% Me₂SO. EG and MetOH to all concentrations and Me₂SO to concentrations lower than 15% have not shown significant toxic effects. The freezing rate −3 °C/min using 15% EG has shown an highest percentage of RVF (rapid, vigorous and forward) spermatozoa (class 3, about 75% of fresh semen) and an highest sperm motility duration.     

Glyoxylate decarboxylation during glycollate oxidation by pea leaf extracts: significance of glyoxylate and extract concentrations

Hydrogen peroxide-dependent glyoxylate decarboxylation occurring during glycollate oxidation by pea leaf extracts (Pisum sativum L.) has been studied in relation to the effects of glyoxylate and extract concentration. With a saturating concentration of glycollate, decarboxylation was greatly stimulated by raising the glyoxylate concentration; at 30°C and with approx. 0.04 nkat of glycollate oxidase (as leaf extract) in the reaction mixture, CO₂ release in the presence of 5 mM glycollate and 5 mM glyoxylate was equal to about 45% of glycollate oxidation. However, CO₂ release at these substrate concentrations was not linearly proportional to the amount of extract supplied and was equal to a diminishing proportion of glycollate oxidation as the amount of extract was increased. This was shown to be due to the low affinity of catalase for H₂O₂, so that the endogenous catalase was able to destroy a larger proportion of the H₂O₂ generated at higher extract concentrations. It is argued that although at high glycoxylate concentrations (5–10 mM) in vitro, glyoxylate decarboxylation can be made to equal more than a third of the glycollate oxidised, less than 10% of the glyoxylate generated in vivo is likely to be decarboxylated in peroxisomes where high concentrations of glycollate oxidase and catalase are localised and where high concentrations of glyoxylate are unlikely to be maintained.Abbreviation PHMS pyrid-2-yl--hydroxymethane sulphonic acid     

Improvement of European eel sperm cryopreservation method by preventing spermatozoa movement activation caused by cryoprotectants

Sperm production has been obtained from European and Japanese eels, but its quality and quantity tend to be changeable. So, its cryopreservation has been tried in both species. Dimethyl sulfoxide (Me₂SO) is the best cryoprotectant for European eel sperm, but increases the medium osmolality, inducing the activation of spermatozoa motility. To avoid this, different combinations of pH (6.5 and 8.5) and NaHCO₃ concentrations (20, 40 and 80 mM) were tested with two Me₂SO concentrations (5% and 10%). Foetal bovine serum (FBS, 25% v/v) was added as a membrane protector to all the freezing media used in the different experiments. The highest Me₂SO and NaHCO₃ concentrations at pH 6.5 caused the best post-thawing motility (26 ± 4%). A second experiment was carried out testing media with Me₂SO 10% with additional NaHCO₃ concentrations (100 and 120 mM). The highest post-thawing motility (38 ± 3%) was found in the media containing NaHCO₃ 100 mM, but no significant difference was observed compared with the best in the previous experiment (NaHCO₃ 80 mM). In a parallel experiment, aiming to improve the protection against the cryopreservation process, bovine serum albumin (BSA, 5% w/v) was added instead of FBS. Lower motilities were registered with BSA as membrane protector. Spermatozoa activation caused by addition of Me₂SO can be prevented using high NaHCO₃ concentrations, improving the cryopreservation process. This effect seems be based on some of the products dissociated from NaHCO₃ in aqueous solution, affecting the intracellular pH, essential in the sperm motility.     

Evidence for a dual pathway in platelet activating factor-induced aggregation of rat polymorphonuclear leucocytes

The purpose of this study was to determine the role, if any, of Leukotriene B₄ (LTB₄) in Platelet Activating Factor (PAF)-induced aggregation of rat polymorphonuclear leucocytes (PMNs). Exposure of rat PMNs to 10⁻⁷ M PAF resulted in the release of 4.5 ± 0.7 ng/10⁷ cells of LTB₄ measured by radioimmunoassay. However, the maximum aggregation of PMNs achieved by exposure to LTB₄ (10⁻⁷M) was only 50% of that produced by maximally aggregating concentrations of PAF (10⁻⁷M). 5-Lipoxygenase inhibitors, BW755c and Nafazatrom at concentrations that completely abolished LTB₄ synthesis inhibited the aggregation induced by PAF only by 40% and 50% respectively. Furthermore, desensitisation experiments revealed that the aggregatory response of PMNs to PAF was only partially refractory to prior treatment with LTB₄ whereas the aggregatory response to LTB₄ was completely refractory to prior treatment with PAF. These results suggest that PAF-induced aggregation of rat PMNs is in part mediated by LTB₄ and in part directly by an as yet unidentified mechanism.     

Impact of novel coronavirus disease (COVID-19) lockdown on ambient air quality of Saudi Arabia

The outbreak of COVID-19 has spread globally affecting human activities but with improvement in ambient air quality. The first case of the virus in the Kingdom of Saudi Arabia was on the 2nd of March 2020. The impact of COVID-19 lockdown on the ambient air quality of the Kingdom of Saudi Arabia for the first time using data from nine cities was determined in this study. Hourly air quality data, based on concentrations of carbon monoxide (CO), particulate matter (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and ozone (O₃), and meteorological conditions (atmospheric temperature, relative humidity, and wind speed) of the nine cities studied were obtained from Saudi Arabian General Authority of Meteorology and Environmental Protection (GAMEP), for the period between January 2019 to May 2020. Significant variation (p < 0.05) was recorded for the five atmospheric pollutants across the cities before and during the lockdown, with lower concentrations during the lockdown except for the concentration of O₃ in Tabuk, Al Qasim, and Haql. This can be a result of NO and O₃ reaction, causing the inability of effective O₃ depletion. The percentage changes in concentrations of CO (33.60%) and SO₂ (44.16%) were higher in Jeddah; PM₁₀ (91.12%) in Riyadh, while NO₂ (44.35%) and O₃ (18.98%) were highest in Makkah. However, even though there was a decrease in pollutants concentrations during the lockdown, the concentrations for CO, PM₁₀, SO₂, NO_2, and O₃ were still above WHO 24 h and annual mean limit levels. The COVID-19 lockdown in the Kingdom of Saudi Arabia revealed the possibility of significant atmospheric pollutant reduction by controlling traffic, activities by industries, and environmentally friendly transportation programs such as green commuting programs.     

Variation of Total and Speciated Arsenic in Commonly Consumed Fish and Seafood

This article compiles available data and presents an approach for predicting human intakes of inorganic arsenic (As_i), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) from marine, estuarine, and freshwater seafood when only total arsenic (As_tot) concentrations are reported. Twenty studies provided data on total arsenic (As_tot) and As_i. Mean As_i concentrations were approximately 10 to 20 ng/g wet weight (ww) in freshwater, anadromous, and marine fish, whereas crustaceans and molluscs had mean As_i concentrations of 40 to 50 ng/g ww. Thirteen studies provided data for MMA and DMA. MMA was seldom detected, whereas DMA averaged 10 ng/g ww in freshwater fish, and 45 to 95 ng/g ww in anadromous fish, marine fish, crustaceans, and molluscs. There was little correlation between As_tot concentrations and As_i concentrations; however, when only As_tot data are available to assess health risks from arsenic in seafood, these data could support conservative, upper end estimates of the percent of As_tot likely to be As_i. For marine and estuarine fish, and crustaceans and molluscs 2–3% of As_tot was As_i at the 75th percentile of the dataset. For freshwater fish As_i was 10% of As_tot at the 75th percentile. Due to the nonlinearity and low carcinogenic potency of DMA, the reported DMA concentrations should not contribute substantially to potential health risks from arsenic in seafood.     

Water quality and the distribution of some fishes in an area of acid sulphate soils,Kalimantan, Indonesia

The drainage from acid sulphate soils severely affects water quality, with pH values commonly around 3, and toxic concentrations of ferrous iron and aluminium. The water quality in an area of acid sulphate soils on the southern coastal plain of Kalimantan, Indonesia, was examined and an inventory of fish species was made. The ionic composition of the water can be described as a simple dilution series of the hypothetical mineral Fe(II)₄Na₈Ca₂Mg₆Al₄H₁₀(SO₄)₂₇, originating from the oxidation of pyrite and weathering products of clay minerals. The oxygen concentrations were variable, ranging from <10% to >100% saturation, without a clear relation to ionic concentrations. Fish were encountered over the entire pH range of 2.8–5.2. Although species distribution showed some correlation with water quality, the species showed widely overlapping ranges, and they are not suitable for use as indicator organisms on the present detailed scale. The most likely explanation for the poor correlation between fish distribution and water quality are seasonal and local fluctuations in quality. These presumably eliminated the more sensitive species, and only those with a high acidity tolerance were found in the area.