Range Of pH Values Research Articles

Studies on Loading Salicylic Acid in Xerogel Films of Crosslinked Hyaluronic Acid.

During the last decades, salicylic acid (SA) and hyaluronic acid (HA) have been studied for a wide range of cosmetic and pharmaceutical applications. The current study investigated the drug loading potential of SA in HA-based crosslinked hydrogel films using a post-loading (osmosis) method of the unmedicated xerogels from saturated aqueous solutions of salicylic acid over a range of pH values. The films were characterized with Fourier-transform infra-red spectroscopy (FT-IR) and ultraviolet-visible (UV-Vis) spectrophotometry in order to elucidate the drug loading profile and the films' integrity during the loading process. Additional studies on their weight loss (%), gel fraction (%), thickness increase (%) and swelling (%) were performed. Overall, the studies showed significant film disintegration at highly acidic and basic solutions. No drug loading occurred at neutral and basic pH, possibly due to the anionic repulsion between SA and HA, whereas at, pH 2.1, the drug loading was promising and could be detected via UV-Vis analysis of the medicated solutions, with the SA concentration in the xerogel films at 28% w/w.

Comparison of Chromatographic Stationary Phases Using a Bayesian-Based Multilevel Model.

Herein, we used a Bayesian multilevel model of chromatographic retention to compare five reversed-phase high-performance liquid chromatography stationary phases: XBridge Shield RP18, XTerra MS C18, XBridge Phenyl, XBridge C8, and Xterra MS C8. For this, we used a large data set of retention times collected using chromatographic techniques coupled with mass spectrometry. The experiments were conducted in gradient mode for an initial mixture of 300 small analytes for a wide range of pH values in methanol and acetonitrile at two temperatures and for three gradient durations. Our analysis was based on a mechanistic model derived from the principles and fundamentals of liquid chromatography and utilized previously reported chromatographic parameters. The data and model were used to characterize the between-column differences in the chromatographic parameters of the neutral, acidic, and basic analytes. The analysis provides an interpretable summary of stationary-phase properties that can be used in decision-making, i.e., finding the best chromatographic conditions using limited experimental data. The proposed approach is an interesting alternative to the existing approaches used to compare chromatographic stationary phases.

Highly efficient electrocatalysts for seawater electrolysis under high current density: A critical review

AbstractAccording to the International Energy Agency (IEA) strategy, water electrolysis will be a second priority for hydrogen production by 2030, which can support sustainable development goals (SDGs). However, for the large‐scale application, especially seawater electrolysis at a high current density, cost and durability of the electrocatalytic system need to be taken into account. Herein, fundamental mechanisms of seawater electrolysis in a wide range of pH values, potential electrocatalysts for overall water splitting, recent progress on synthesis electrocatalysts and basic principles for the evaluation of electrocatalysts are reviewed. Subsequently, critical parameters and issues for scaling‐up of seawater electrolyzers are critically discussed. Finally, future prospects for completing sustainable hydrogen production from seawater for sustainable development are outlooked. It is anticipated to offer guidelines for the design and production of innovative electrocatalysts with high electrocatalytic activity and durability for the industrial scale application.

Nitrogen sulfur co doped carbon quantum dots as fluorescent probe for quantitative determination of monosodium glutamate in food samples

A validated, simple, and ecofriendly spectrofluorometric method has been developed for the determination of monosodium glutamate (MSG) in food matrices utilizing novel nitrogen and sulfur co doped carbon quantum dots (NS-CQDs) as fluorescent probes. MSG is one of the most commonly used food additives that has distinct taste. The proposed method is based on the finding that MSG can effectively enhance the fluorescence intensity of NS-CQDs as a result of the formation of CQDS-MSG complex via electrostatic interaction and electron transfer from the excited CQDs to MSG. NS-CQDs have been synthesized using citric acid and D, L- methionine as precursors and the formed quantum dots were characterized by FTIR spectroscopy and transmission electron microscopy (TEM). NS-CQDs display bright blue fluorescence at emission wavelength 440 nm after excitation wavelength 330 nm with a quantum yield of 38.68% and a production yield of 88.75%. The fluorescence intensity of CQDs was found to be stable over a wide range of pH value (4.0–10). Under optimal experimental conditions, there was a linear relationship between the increased fluorescence and MSG concentration over the range of 25–250 µg/mL with limit of detection and limit of quantification 6.20 and 18.79 µg/mL respectively. NS-CQDs show excellent selectivity to MSG and the proposed method has been applied for MSG determination in two food products with satisfactory recoveries achieved by standard addition method.

Tubular and bio-based carbons as binder-free gas diffusion electrodes for heterogeneous electro-Fenton to remove micropollutants

Heterogeneous electro-Fenton (HEF) coupled with anodic oxidation offers a plug-and-treat and chemical-free process over a wide range of pH values for removing recalcitrant micropollutants (MPs). This work introduces a self-standing and Fe-containing tubular carbon as a gas diffusion electrode (GDE) for HEF. Unlike planar Fe-containing carbon electrodes, as-synthesized carbons contain no fluorinated polymer as a subgroup of perfluoroalkyl and polyfluoroalkyl substances (PFAS), omitting the risk of secondary pollution due to undesired PFAS release during electrolysis. The implementation of GDE enables the increase of current densities up to 25mAcm−2, approaching relevant conditions for real-life applications. The altering pore structure on the gas channel side illustrates the possibility of minimizing GDE flooding without using hydrophobic and fluorinated polymers. GDEs without catalyst shows a specific H2O2 production rate of 3.6mgcm−2h−1 with a current efficiency of 56% at an applied current density of 8.5mAcm−2. Additionally, the Fe-containing GDE removes sulfamethoxazole (SMX) and carbamazepine (CBZ), revealing a declined degradation rate in a mixture, especially for a more recalcitrant pollutant such as CBZ. This work reveals the potential of as-synthesized self-standing tubular GDEs as PFAS-free electrodes for a decentralized and modular water treatment unit.

The Effect of pH on the Viscoelastic Response of Alginate-Montmorillonite Nanocomposite Hydrogels.

Ionically cross-linked alginate hydrogels are used in a wide range of applications, such as drug delivery, tissue engineering, and food packaging. A shortcoming of these gels is that they lose their strength and degrade at low pH values. To develop gels able to preserve their integrity in a wide range of pH values, Ca-alginate-montmorillonite nanocomposite gels are prepared, and their chemical structure, morphology, and mechanical response are analyzed. As the uniformity of nanocomposite gels is strongly affected by concentrations of MMT and CaCl2, it is revealed that homogeneous gels can be prepared with 4 wt.% MMT and 0.5 M CaCl2 at the highest. The viscoelastic behavior of nanocomposite gels in aqueous solutions with pH = 7 and pH = 2 is investigated by means of small-amplitude compressive oscillatory tests. It is shown that Ca-alginate-MMT nanocomposite gels preserve their integrity while being swollen at pH = 2. The experimental data are fitted by a model with only two material parameters, which shows that the elastic moduli increase linearly with a concentration of MMT at all pH values under investigation due to formation of physical bonds between alginate chains and MMT platelets. The presence of these bonds is confirmed by ATR-FTIR spectroscopy. The morphology of nanocomposite gels is studied by means of wide-angle X-ray diffraction, which reveals that intercalation of polymer chains between clay platelets increases the interlayer gallery spacing.

The implication of the hydrogeochemical processes for groundwater chemistry in a semi-arid region: A case study of the Bokoya massif (Central Rif, Morocco)

Natural and anthropogenic factors control groundwater chemistry in the semi-arid area in northern Morocco called Bokoya massif. The main goal of this study was to evaluate the geochemical processes that affected groundwater mineralization in the Bokoya massif. As a result, In April 2016, sixty-one (61) water samples were collected from various locations, including wells and springs throughout the Bokoya massif, and analyzed for physicochemical parameters using standard methods. The descriptive study of the physicochemical parameters revealed that the waters were neutral to slightly basic (pH values range between 7,16 and 8,5) and moderately to strongly mineralized (TDS values range between 555,20 and 7980,10 mg/l). Sodium chloride was the dominant hydrochemical facies in the groundwater of the study area, with a percentage reaching (80%) noting the minority of magnesium bicarbonate facies and the absence of sodium bicarbonate and chlorinated calcium type. The tests of the ionic ratio (Cl- /Na+, Cl-/HCO3- versus Cl-, Ca2+/Mg2+, Ca2+/SO4-, Ca2+/Mg2+ versus Cl-, (Ca2+ Mg2+)/ HCO3-), indicate that the order of the dominant cations is Na+ >Ca2+>Mg2+>K+ and of the dominant anions is Cl- >HCO3->SO42-. It suggests that the dominant factors controlling water chemistry are rock dissolution and evaporation, silicate weathering, and ion exchange. Gibbs diagram defines the relationship between water chemistry and the lithology of the aquifer. It showed that most of the groundwater composition in this area is linked to the geochemical processes of evaporation and crystallization, and carbonates and silicate alteration control the minority.

<i>Nocardiopsis synnemataformans</i> NBRM9, an extremophilic actinomycete producing extremozyme cellulase, using lignocellulosic agro-wastes and its biotechnological applications

<abstract> <p>Actinomycetes are an attractive source of lignocellulose-degrading enzymes. The search for actinomycetes producing extremozyme cellulase using cheap lignocellulosic waste remains a priority goal of enzyme research. In this context, the extremophilic actinomycete NBRM9 showed promising cellulolytic activity in solid and liquid assays. This actinomycete was identified as <italic>Nocardiopsis synnemataformans</italic> based on its phenotypic characteristics alongside phylogenetic analyses of 16S rRNA gene sequencing (OQ380604.1). Using bean straw as the best agro-waste, the production of cellulase from this strain was statistically optimized using a response surface methodology, with the maximum activity (13.20 U/mL) achieved at an incubation temperature of 40 °C, a pH of 9, an incubation time of 7 days, and a 2% substrate concentration. The partially purified cellulase (PPC) showed promising activity and stability over a wide range of temperatures (20–90 °C), pH values (3–11), and NaCl concentrations (1–19%), with optimal activity at 50 °C, pH 9.0, and 10% salinity. Under these conditions, the enzyme retained >95% of its activity, thus indicating its extremozyme nature. The kinetics of cellulase showed that it has a V<sub>max</sub> of 20.19 ± 1.88 U/mL and a Km of 0.25 ± 0.07 mM. The immobilized PPC had a relative activity of 69.58 ± 0.13%. In the in vitro microtiter assay, the PPC was found to have a concentration-dependent anti-biofilm activity (up to 85.15 ± 1.60%). Additionally, the fermentative conversion of the hydrolyzed bean straw by <italic>Saccharomyces cerevisiae</italic> (KM504287.1) amounted to 65.80 ± 0.52% of the theoretical ethanol yield. Overall, for the first time, the present work reports the production of extremozymatic (thermo, alkali-, and halo-stable) cellulase from <italic>N. synnemataformans</italic> NBRM9. Therefore, this strain is recommended for use as a biotool in many lignocellulosic-based applications operating under harsh conditions.</p> </abstract>

Efficient phosphate removal utilizing N, Zn-doped carbon dots as an innovative nanoadsorbent.

The primary goal of this study is to examine PO4 3- adsorption from aqueous solutions using zinc-doped carbon dots (Zn-N-CDs) as a new adsorbent and cost-effective technique. Zn-N-CDs were produced through a hydrothermal process and subsequently identified using various techniques. The effect of reaction time, temperature, pH, ionic strength, adsorbent dosage, initial PO4 3- concentration, and anion competition (NO3 -, Cl-, HCO3 -, and SO4 2-) on PO4 3- adsorption using Zn-N-CDs were investigated. The characterization results depicted that Zn-N-CDs have a spherical structure without obvious aggregation and revealed the amorphous nature of carbon dots with many pores. Zn-N-CDs had a high affinity for adsorbing PO4 3-, reaching equilibrium within 5 minutes. While PO4 3- adsorption reduced with an increase in temperature, it increased with pH and ionic strength. The optimal conditions for PO4 3- adsorption were determined to be pH 8, 100 mM KCl as an ionic strength, and 5 g L-1 of Zn-N-CDs. The presence of SO4 2- and HCO3 - as competing anions slightly decreased PO4 3- adsorption. Thermodynamic studies revealed that PO4 3- adsorption onto Zn-N-CDs was endothermic, spontaneous, and disordered, as evidenced by ΔG° < 0, ΔH° > 0, and ΔS° > 0. The experimental data fit well with a pseudo-second-order kinetic model (R 2 = 0.999) and the Freundlich isotherm model (R 2 = 0.9754), signifying that PO4 3- adsorption onto Zn-N-CDs occurs through multi-layer and chemi-sorption mechanisms. Overall, Zn-N-CDs indicated a great capability to adsorb high concentrations of PO4 3- across a wide range of pH values, indicating their potential for environmental remediation.

Experimental Design Modelling and Optimization of the Intercalation of Levofloxacin and Salicylic Acid into the Structure of ZnAl-LDH by Response Surface Method: in vitro Study of Release Kinetics, Antibacterial and Anti- Inflammatory Activities

In recent years, solid-state engineering has emerged as a promising method for improving the stability and potency of antibiotics and anti-inflammatory drugs. This study focuses on the design and optimization of the intercalation of levofloxacin (an antibiotic drug) and salicylic acid (an anti-inflammatory drug) into zinc-aluminium-layered double hydroxide galleries using response surface method. Release studies revealed that a burst release phenomenon was observed at the beginning of the release assay, and the pH value (in the range of 5.8-7.4) had very little influence on the levofloxacin and salicylic acid release efficiency. This indicates that zinc-aluminium-layered double hydroxide could be an effective inorganic carrier for levofloxacin and salicylic acid over a wide range of pH values. Four kinetic models were used to study the release kinetics and the drug release mechanism was also discussed. In addition, the intercalation of levofloxacin and salicylic acid into zinc-aluminium-layered double hydroxide exhibited enhanced antibacterial activity against Gram-positive Bacillus subtilis. The cell viability assay revealed non-toxic behavior of levofloxacin and salicylic acid intercalated into zinc-aluminium-layered double hydroxide against the monocyte/macrophage-like cell line.

Collagen properties of Indonesian local sheepskin isolated using acid and enzymatic methods.

This study aimed to investigate the physical properties of Indonesian local sheep skin collagen extracted by acid and enzymatic methods. Collagen was isolated from Pure Breed Garut Sheep (Ovis aries sp.) skin, 1.5 years old. The skins were obtained from a local slaughterhouse in Cirebon, Indonesia. The solvents used were CH3COOH and three different enzymes: neutrase, alcalase, and bromelain. The highest yields of extracted collagen were bromelain-soluble collagen (BSC), which reached 37.07%. The range of Ph values for all samples started from 4.01 to 4.76. The viscosity values (cP) of acid-soluble collagen (ASC), neutrase-soluble collagen (NSC), alcalase-soluble collagen (LSC), and BSC were 3.42, 3.90, 3.45, and 3.12, respectively. Regarding SDS-PAGE analyses, Garut sheepskin collagen is categorized as collagen type I, which has a molecular weight of about 140.99 to 148.74 kDa for α1 and around 110 to 111.86 kDa for α2. The results of FTIR and DSC analyses for all samples show the same motif with commercial collagen motifs based on the literature. Garut sheep skin has the potential to be an alternative raw material source for producing collagen. Collagen extracted using a combination of CH3COOH and bromelain enzyme showed the most desirable results in almost every characteristic.

Resistance of various soil geosystem bacteria to enzymatic lysis at different pH

Bacteria appear to be an inevitable element of soil geochemistry because they participate actively in chemical transformations of soil media components. One of the factors determining the composition of bacterial population in soil is resistance of bacteria to enzymes which hydrolyze cell walls. In the following research, resistance of bacteria (Priestia megaterium, Micrococcus luteus and Escherichia coli) to lysozyme in the pH range appropriate for soils is investigated. All the three species are proved to be most sensitive to lysozyme in slightly alkaline conditions (P. megaterium is least resistant at pH 8.0, M. luteus at pH 8.3, E. coli at pH 8.5), and resistance of all the three microorganisms in the range of pH values of 6.0—7.0 changes insignificantly. A possible factor defining the pH optimum for lysozyme activity in relation to these bacteria is the structure of negatively charged components of their cell walls and outer membranes.

Investigation of Ln3+ complexation by a DOTA derivative substituted by an imidazothiadiazole: synthesis, solution structure, luminescence and relaxation properties.

We investigated the coordination properties of original macrocyclic Ln3+ complexes comprising an imidazothiadiazole heterocycle. The thermodynamic stability of the Gd3+ complex was determined by a combination of potentiometric and photophysical measurements. The kinetic inertness was assessed in highly acidic media. The solution structure of the Ln3+ complex was unambiguously determined by a set of photophysical measurements and 1H, 13C, 89Y NMR data in combination with DFT calculations, which proved coordination of the heterocycle to Ln3+. The ability of the imidazothiadiazole moiety to sensitize Tb3+ luminescence was investigated. Finally, the relaxation properties were investigated by recording 1H nuclear magnetic relaxation dispersion (NMRD) profiles and 17O measurements. The water exchange rate is similar to that of GdDOTA as the less negative charge of the ligand is compensated for by the presence of a bulky heterocycle. Relaxivity is constant over a large range of pH values, demonstrating the favorable properties of the complex for imaging purposes.

A pH-enhanced resolution in benchtop NMR spectroscopy.

NMR spectroscopy is one of the most potent methods in analytical chemistry. NMR titration experiments are particularly useful since they measure molecular binding affinities and other concentration-dependent effects. These experiments, however, require a long series of measurements. An alternative to these serial measurements has recently been presented, exploiting a pH (or generally - a concentration) gradient along the NMR tube. The proposed experiment, although efficient, was based on the sensitivity- and hardware-demanding chemical shift imaging (CSI) method. Thus, it is practically limited to high-resolution NMR spectrometers. This paper proposes modifying and adapting the approach to the popular and cost-efficient benchtop NMR machines. Instead of CSI, we use a device that shifts the NMR tube vertically to measure the spectra of different sample volumes, which have different pH values due to the established gradient along the tube. We demonstrate the potential of the method on the test samples of L-tyrosine and 2,6-lutidine, and two real samples from the food industry - an infant formula and an energy drink. The proposed method boosts spectral resolution and allows for the sampling of a broader range of pH values when compared to the original approach.

Solvent‐Induced Deformation of Aramid Nanofibers for Ultrahigh‐Flux Nanofiltration Membranes

AbstractAramid nanofibers (ANFs), as promising organic nano building blocks for their high mechanical strength and thermal stability, are widely applied to fabricate energy‐efficient membranes for ionic and molecular sieving in aqueous solutions. However, the existing ANFs often have small diameters, limiting the permeability of the resulting membranes. Here, the ANFs with a diameter in the hundred‐nanometer scale are fabricated through a progressive protonation process, in which dimethylformamide as a secondary deprotonation solvent is added into dimethyl sulfoxide to provide a mild deformation environment. Then, the deformed ANFs are applied to prepare membranes with a larger pore size distribution and higher surface charge. Notably, the water flux of the resulting membranes can reach up to 410 L m−2 h−1 bar−1, which is 40 times higher than commercially available nanofiltration membranes and much higher than currently reported ANF‐based membranes. Impressively, these membranes with super‐stable nanochannels maintain a high water flux of over 194 L m−2 h−1 bar−1 in a wide range of pH values from 4 to 10 and show excellent long‐term durability over 120 h. The application of deformed ANFs provides a new and promising approach for designing the next generation nanofiltration membranes which balance the trade‐off between permeability and selectivity.

Spectroelectrochemical and Computational Study of Quinoline Based Molecules - Potential Anti-Alzheimer’s Drugs

Here, we present combined experimental and theoretical studies on the spectroelectrochemical properties of 8-aminoquinoline (8AQ). 8AQ is a model molecule for drugs that can chelate copper(II) ions, and thus it may find applications in halting the development of Alzheimer’s disease.Although over a hundred years have passed since Alzheimer’s disease (AD) was first described, it remains incurable to this day. According to one of the leading hypotheses, peptides from the β-amyloid (Aβ) group are responsible for the development of AD. By binding copper(II) ions, Aβs form complexes whose presence promotes the formation of harmful, highly active compounds called reactive oxygen species (ROS) and reactive nitrogen species (RNS). In a series of recent studies, we investigated the differences in electrochemical properties of Cu(II)-complexes with the amyloids Aβ(11-16) and Aβ(3-16) with their pyroglutamated versions, pAβ(11-16) and pAβ(3-16). [1,2] These results showed that the pyroglutamate amyloids are conducive to Cu(II)-reduction at a potential associated with ROS production. Given the abundance of pyroglutamated amyloids in senile plaques, this could have important consequences for AD pathophysiology. Overproduction of ROS and RNS can cause neuron death. Therefore, substances that can aid in removing copper(II) ions from β-amyloids could block the formation of ROS and RNS. Recently, a new quinoline derivative with unique properties has undergone preclinical studies. However, little is known about the redox properties of such molecules, which may be crucial in the early stages of testing potential therapeutic substances.Therefore, we aimed to perform electrochemical and spectroelectrochemical studies of a model molecule, 8-aminoquinoline, whose redox properties were not yet well characterized To fully characterize both anodic and cathodic processes, we used cyclic and pulse voltammetry over a wide range of pH values, including physiological (pH=7.4). In addition, the experimental results were supported by DFT-based computational studies exploring the energy landscapes of the possible reactions and advancing understanding of the electrochemical phenomena.The kind of electrochemical tests presented here may prove of crucial importance for the development of more effective drugs against AD. The high failure rate and relatively poor performance of the recently approved treatment indicates the need to extend preclinical studies with new, so far unused techniques, allowing a more complete picture to be obtained of the effectiveness and toxicity of the potential drug candidates.[1] M.Z. Wiloch, N. Baran, M. Jönsson‐Niedziółka, The Influence of Coordination Mode on the Redox Properties of Copper Complexes with Aβ(3‐16) and Its Pyroglutamate Counterpart pAβ(3‐16), ChemElectroChem. 9 (2022). https://doi.org/10.1002/celc.202200623.[2] M.Z. Wiloch, M. Jönsson-Niedziółka, Very small changes in the peptide sequence alter the redox properties of Aβ(11–16)-Cu(II) and pAβ(11–16)-Cu(II) β-amyloid complexes, Journal of Electroanalytical Chemistry. 922 (2022) 116746. https://doi.org/10.1016/j.jelechem.2022.116746.

Boosting Photocatalytic Water Splitting of Polymeric C60 by Reduced Dimensionality from Two-Dimensional Monolayer to One-Dimensional Chain.

The recent synthesis of monolayer fullerene networks (Hou, L., et al. Nature 2022, 606, 507) provides new opportunities for photovoltaics and photocatalysis because of their versatile crystal structures for further tailoring of electronic, optical, and chemical function. To shed light on the structural aspects of the photocatalytic water splitting performance of fullerene nanomaterials, we compare the photocatalytic properties of individual polymeric fullerene chains and monolayer fullerene networks from first-principles calculations. We find that the photocatalytic efficiency can be further optimized by reducing the dimensionality from two-dimensional (2D) to one-dimensional (1D). The conduction band edge of the polymeric C60 chain provides an external potential for the hydrogen reduction reaction much higher than that of its monolayer counterparts over a wider range of pH values, and there are 2 times more surface active sites in the 1D chain than in the 2D networks from a thermodynamic perspective. These observations identify the 1D fullerene polymer as a more promising candidate as a photocatalyst for the hydrogen evolution reaction in comparison to monolayer fullerene networks.

Investigation of novel radical scavenging mechanisms in the alkaline environment: Green, sustainable and environmentally friendly antioxidative agent(s)

Pharmaceutical and industrial utilization of synthetic chemicals has an immerse impact on the environment. In that sense, novel chemicals with potential for industrial application should be investigated for their behaviour in reactions with hydroxyl radical, simulating AOPs (Advanced Oxidation Processes). AOPs are known for being highly effective in wastewater management and natural water remediation. In this paper, exhaustive research on the radical scavenging activity of a newly synthesized coumarin derivative (4HCBH), as a representative of the series of coumarin-benzohydrazides with high antioxidative potential was conducted. This study took into consideration the pH value range significant for practically all living organisms (pH = 7.0–8.5). According to the experimentally obtained results, the 4HCBH showed an increase in radical scavenging activity, following the slight increase in pH values, which suggested that the formation of anionic form of 4HCBH is responsible for its antiradical activity. Further investigations led to the postulation of a novel mechanistic approach called Sequential Proton Loss Electron Transfer – Radical-Radical Coupling (SPLET-RRC), in which, by a series of steps, a new, stable compound was formed. Furthermore, it was demonstrated that the product generated through SPLET-RRC showed lower toxicity than the parent molecule.

Isolation and identification of vapA-absent Aeromonas salmonicida in diseased snakehead Channa argus in China.

Aeromonas salmonicida is the typical pathogen causing furunculosis, reported widely in salmonids. Because of multiple serotypes, the control of A. salmonicida-caused disease has increasingly received much attention. Recently, A. salmonicida infection was reported in non-salmonid fish species. Here, a pathogenic A. salmonicida, named as As-s, was isolated from cultured snakehead (Channa argus) in a local fish farm in Shandong, China. As-s displayed clear hemolysis, amylase, and positive catalase activities, and grew at a wide range of temperatures (10-37 °C) and pH values (5.5-8.5). As-s was highly sensitive to cefuroxime sodium, ceftriaxone, ceftazidime, piperacillin, and cefoperazone and also apparently sensitive to chloramphenicol, erythromycin, and 25% cinnamaldehyde. The Virulence array protein gene cloning' results suggested that As-s has this gene compared with the other two vapA-containing strains, despite a close relationship of these strains via phylogenetic analysis. Severe ulcers on skin, muscle, and abnormal liver, and hemorrhage in pectoral/ventral fins and anal region were observed, and exophthalmos were also noticed in infected juvenile snakehead, as well as necrosis and infiltration of blood cells emerged in the internal organs using pathological section. In addition, As-s caused high mortality in snakehead, consistently with its immune gene response. This study reports the first isolation of vapA-absent A. salmonicida in snakehead.

Pollution Levels of Three Heavy Elements and some Environmental Factors for Mud Farm Water North of Thi-Qar

The current study was conducted to determine the levels of pollution of the three heavy elements, and some environmental factors for the water of a mud farm north of Thi Qar district of Shatrah, at the village of Al-Ajja Al-Buhan, near Hor Al-Ghomqa, it is 55 km away from the center of Al-Nasiriyah, from 5/11/2022 to 5/4/2023. The study included measuring the temperature of water and air, turbidity, electrical connection, salinity, total dissolved solids, pH and dissolved oxygen. Water samples were analyzed on a monthly basis. The results of the study showed that the air temperature ranged between 22-30 °C, the water temperature ranges between 17-20°C, turbidity ranges from 8.11-11.3 NTU, the electrical conductivity of the salinity recorded values ranging from 1.19-1.99 μS/cm, total dissolved solids recorded values ranging between 6543 - 11165 mg / L, the pH values range from 7.17-7.98, between neutral to lightly basic, dissolved oxygen values ranged between 6.77-8.9 mg/L during the months of the experiment. Standard methods were used to estimate the concentrations of heavy metals in water, by flame atomic absorption spectrophotometer. The results showed that the highest total concentration of zinc, copper and cadmium, recorded in water during the months of the year amounted to 22.89, 1.99 and 2.99 μg / L, respectively. The results showed that the accumulation of elements heavy was, concentrations in the water of zinc > copper > cadmium.