Heavy Metal Binding Research Articles

Selenourea for Experimental Phasing of Membrane Protein Crystals Grown in Lipid Cubic Phase

Heavy-atom soaking has been a major method for experimental phasing, but it has been difficult for membrane proteins, partly owing to the lack of available sites in the scarce soluble domain for non-invasive heavy-metal binding. The lipid cubic phase (LCP) has proven to be a successful method for membrane protein crystallization, but experimental phasing with LCP-grown crystals remains difficult, and so far, only 68 such structures were phased experimentally. Here, the selenourea was tested as a soaking reagent for the single-wavelength anomalous dispersion (SAD) phasing of crystals grown in LCP. Using a single crystal, the structure of the glycerol 3-phosphate acyltransferase (PlsY, ~21 kDa), a very hydrophobic enzyme with 80% membrane-embedded residues, was solved. Remarkably, a total of 15 Se sites were found in the two monomers of PlsY, translating to one selenourea-binding site per every six residues in the accessible extramembrane protein. Structure analysis reveals that surface-exposed selenourea sites are mostly contributed by mainchain amides and carbonyls. This low-specificity binding pattern may explain its high loading ratio. Importantly, both the crystal diffraction quality and the LCP integrity were unaffected by selenourea soaking. Taken together, selenourea presents a promising and generally useful reagent for heavy-atom soaking of membrane protein crystals grown in LCP.

Combined interactions of amino acids and organic acids in heavy metal binding in plants

ABSTRACT This research focused on the different approaches to the transport and internal chelation of metals with amino acids and organic acids in plants. Therefore, in the first phase, the plants studied were identified the characteristics of the bioaccumulation factors. Steria pumila, Echium angustifolium, Typha angustifolia, Sisymbrium austriacum were identified as hyperaccumulators (Cd, Ni), accumulators (Pb, Sn, and Se), excluders (Cr, Hg). On the other hand, the Sisymbrium austriacum only showed the characteristic of the accumulator for Cr. In the second phase, the combined effects of amino acids and organic acids on the chelation of heavy metals in plants were tested by a multi-linear regression model. Related to our hypothesis, Amino acids; Gly and Leu (Cd), Trp and Ile (Pb), Asp, Ser, and Leu (Cr), Ser (Hg), Trp and Glu (Ni), Asp, Thr, and Gly (Sn), Asn and Leu (Se), Organic acids; Malonic and Malic acid (Cd), Malonic acid (Pb), Oxalic and Malic acid (Cr), Oxalic, Succinic, Citric and Butyric acid (Hg), Malonic and Malic acid (Ni), Malonic, Maleic, and Malic acid (Sn), Malonic and Citric acid (Se) were concluded that had combined effect for heavy metal’s phytochelation ability into plants.

Probing heavy metal binding to phycobiliproteins

Blue‐green algae, also known as cyanobacteria, contain some of the most efficient light‐harvesting complexes known. These large, colourful complexes consist of phycobiliproteins which are extremely valuable in the cosmetics, food, nutraceutical and pharmaceutical industries. Additionally, the colourful and fluorescent properties of phycobiliproteins can be modulated by metal ions, making them highly attractive as heavy metal sensors and heavy metal scavengers. Although the overall quenching ability metal ions have on phycobiliproteins is known, the mechanism of heavy metal binding to phycobiliproteins is not fully understood, limiting their widespread quantitative applications. Here, we show using high‐resolution native mass spectrometry that phycobiliprotein complexes bind metal ions in different manners. Through monitoring the binding equilibria and metal‐binding stoichiometry, we show in particular copper and silver to have drastic, yet different effects on phycobiliprotein structure, both copper and silver modulate the overall complex properties. Together, the data reveals the mechanisms by which metal ions can modulate phycobiliprotein properties which can be used as a basis for the future design of metal‐related phycobiliprotein applications.

Metallothionein-1 gene from Exopalaemon carinicauda and its response to heavy metal ions challenge

Metallothioneins (MTs) belong to a conserved low-molecular-weight protein family that participates in heavy metal binding and detoxification. EcMT-1 was amplified by PCR from genomic DNA of Exopalaenon carinicauda. It contained a 180 bp open reading frame and encoded 59 amino acids. A total of 18 cysteine (Cys) residues were found in the deduced amino acid sequence, which was consistent with the Cys-rich characteristics of MTs. EcMT-1 was mainly expressed in hepatopancreas, followed by stomach and gill. The expression profiles of EcMT-1 indicated that EcMT-1 was significantly increased at 24, 48 h and 12, 24, and 48 h under the treatment of 2.5 μmol/L CdCl2 and 50 μmol/L CuSO4. The expression of EcMT-1 at gastrula stage was very low; it was detectable until nauplius stage, and the highest expression level appeared in the postlarvae stage.

Utilizing Reclaimed Petroleum Waste to Synthesize Water-Soluble Polysulfides for Selective Heavy Metal Binding and Detection

Many industrial processes produce waste with toxic and precious metal pollutants. Current remediation strategies lack the selectivity needed to effectively eliminate heavy metals. Thus, materials are needed to effectively treat waste streams and contaminated waterways. Sulfur is well known for its ability to selectively bind heavy metals. Additionally, excess sulfur is produced on large scales during petroleum refinement making it inexpensive and abundant. Inverse vulcanization enables surplus sulfur to be repurposed into high sulfur content materials without the need for solvents. These polysulfides have demonstrated many beneficial applications including heavy metal binding. However, they are plagued by low solubility and dominated by hydrophobic monomers. Here, elemental sulfur and charged monomers, including diallyl dimethylammonium chloride (DADMAC), were combined for the first time in a one-step reaction forming water-soluble polysulfides. The water solubility allows for complete interaction of dissolved metal ions with the polymer, rather than surface-level interaction as is the case for traditional inverse vulcanized polymers. Additionally, the charged polysulfides exhibit enhanced solubility in organic solvents, making solution-based characterization such as NMR more accurate. Poly(S-DADMAC) has demonstrated selective binding to gold and silver inducing the formation of a macromolecular complex that precipitates from solution. Additionally, these polymers interact with other heavy metals including lead and copper demonstrating a visible color change at low concentrations that may be used to detect the presence of these metals in wastewater. The low cost, ease of preparation, and scalability make these polysulfides practical as well as functional.

МІНЕРАЛЬНИЙ СКЛАД, ГЕОХІМІЧНІ ОСОБЛИВОСТІ І ВПЛИВ НА ДОВКІЛЛЯ ВІДВАЛУ ФОСФОГІПСУ НОВОРОЗДІЛЬСЬКОГО ЗАВОДУ СКЛАДНИХ МІНЕРАЛЬНИХ ДОБРИВ (ЛЬВІВСЬКА ОБЛ.)

Phosphogypsum of Novorozdilsky Plant of Complex Mineral Fertilizers (Lviv region) is a typical artificial neogenic mineral formation, solid waste by-product generated when sulphuric acid reacts with the phosphorus-containing ores (apatite or phosphorite concentrates) during manufacturing of phosphoric acid. The raw materials for fertilizer production at the plant were sulphuric acid, which was obtained from the sulphur ores of Rozdilske SMCE “Sirka”, apatite concentrate from the Khibiny deposit (Kola Peninsula) and, to a lesser extent, phosphorite concentrate from sedimentary phosphorites. The plant has not been operating since 1995, but 4.5 million tons of phosphogypsum and also acidic mineralized water in the settling lake have accumulated on its territory since then. Gypsum (85–95 %) and bassanite (5–10 %) dominate in the mineral composition of phosphogypsum, there are also undissolved apatite (up to 2–3 %) and trace amounts of minerals that were originally in apatite concentrate (quartz, nepheline, pyroxene, aegirine, feldspar, biotite, etc.). The surface of the phosphogypsum heap is a phytophilous man-made substrate that is actively overgrown with woody vegetation. This is due to the filtration properties of phosphogypsum Василь Дяків, Ельвіра Джумеля, Мирослав Ковальчук та ін. 106 ISSN 2078-6220. Мінералогічний збірник. 2022. № 72 (they promote water accumulation and leaching of phytotoxic compounds from the zone of active water exchange) and the presence of a significant amount of phosphates. Currently, a dense aspen-sea buckthorn forest grows on the slopes of the dump. Acidic infiltrates are formed in the process of infiltration of precipitation through the thickness of the phosphogypsum dump, they are accumulated in the settling lake (Central/Acid Lake). In terms of chemical composition, it is sulphate-phosphate sodium-magnesium-calcium water with high fluorine content and mineralization of 2931.6 mg/dm3. The cessation of the use of the lake (as a settling tank for the plant's circulating waters) and the constant accumulation of infiltrate have led to a number of environmental problems. Acidic infiltrates flow into the mine canal and significantly impair the quality of water in it. Only due to the dilution of infiltrates with clean water of the drainage channel (with a flow rate of three to four times higher) before flowing into the transboundary Dniester River hydrochemical composition of water meets the normative values of salt composition and content of major pollutants. Deterioration of the water quality of the mine canal and, as a consequence, pollution of the Dniester in case of prolonged drought or reduction of the debit of the drainage canal are envisaged. To minimize the negative impact of the phosphogypsum dump on the environment, a project to build a cascade of filter dams from local carbonate materials has been proposed. Limestones have the ability to neutralize acidic waters; they are highly permeable and contain sulphur, which causes the binding of heavy metals to insoluble compounds. Due to the interaction of carbonates with acidic infiltrates, water-insoluble calcium phosphates and calcium fluoride (fluorite) are formed, which helps to purify water from F and P, and newly formed hydrates reduce the moisture content of the phosphogypsum mixture with flotation tails. The proposed approach will make it possible to control a constant source of pollution and restore the ecological balance disturbed by economic activities

Investigation on Immune-Related Protein (Heat Shock Proteins and Metallothionein) Gene Expression Changes and Liver Histopathology in Cadmium-Stressed Fish.

Heat shock proteins (HSP) are highly conserved in their structure and released in case of stress. Increased metallothionein (MT) synthesis is associated with increased capacity for binding heavy metals. Healthy juveniles of grass carp were exposed to sublethal dose (1.495 mg L−1) of cadmium for 28 days. Simultaneously, a control group was also run to compare difference of total RNA expression levels in cadmium-treated and control groups. The cadmium levels in the tissues of treated fish recorded were 1.78 ± 0.10 mg L−1, 1.60 ± 0.04 mg L−1, and 2.00 ± 0.05 mg L−1, respectively. Several histological alterations including edema, hemorrhage, dilated sinusoids, hypertrophy, hyperplasia, congestion of central vein, and nuclear alterations were observed in cadmium-exposed fish. Stress gene (metallothionein and heat shock proteins) mRNA transcription levels were studied by mRNA extraction and cDNA preparation by using PCR. The expression level of heat shock protein gene was higher as compared to metallothionein and beta-2-microglobulin gene after cadmium exposure. This study reports various stress-related immune-responsive changes of immune proteins, heat shock proteins, metallothionein, and histopathological changes in fish due to cadmium toxicity that make the fish immunocompromised which may be considered as the biomarkers of cadmium toxicity in other experimental species.

Physical Separation of Contaminated Soil Using a Washing Ejector Based on Hydrodynamic Cavitation

A washing ejector is a pre-treatment technology used to remediate contaminated soil by separating fine particles. The washing ejector developed in this study is a device that utilizes fast liquid jets to disperse soil aggregates by cavitation flow. The cavitation phenomenon is affected by the Bernoulli principle, and the liquid pressure decreases with the increase in kinetic energy. The cavitating flow of the fluid through the Ventrui nozzle can remove surface functional groups and discrete particles. The main methodology involves the removal of small particles bound to coarse particles and the dispersion of soil aggregates. Particle collisions occur on the surface soil, such as the metal phase that is weakly bound to silicate minerals. It was observed that the dispersed soil affected the binding of toxic heavy metals and the mineralogical characteristics of the soil. The quantity of oxides, organic matter, and clay minerals affected the properties of the soil. An almost 40–60% removal efficiency of total metals (As, Zn, and Pb) was obtained from the contaminated soils. After treatment by a washing ejector, the volume of fine particles was reduced by 28–47%. When the contaminants are associated with particulates, separation using a washing ejector can be more effective. Therefore, physical separation improves the removal efficiency of heavy metals from soil aggregates.

Relationship between mineralogical phase and bound heavy metals in copper smelting slags

The migration and transformation of hazardous metals in copper smelting slags (CSS) threats the environment. However, the unclear relationship between phases and heavy metals in CSS hinders the development of harmless technology. In this work, we investigated the mineralogical composition of CSS and the corresponding heavy metal distribution, and explored the relationship between mineral phases and bound heavy metals. Fayalite (47.4%) was identified as the main phase in CSS by XRD refinement along with other phases of hedenbergite (38.7%), magnetite (11.0%) and iron (2.9%). Heavy metals mainly distributed in fayalite and less in hedenbergite and other phases. The specific sequential extraction showed fayalite was difficult to extract since 89.7% arsenic, 85.0% lead and 76.9% copper were tightly bound with these minerals. It meant that fayalite had a much stronger binding ability with heavy metals than that of other phases. Fayalite could transform into magnetite during alkali disaggregation resulting in the changing of heavy metal binding from strong to weak. This work is an approximation to break through the bottleneck of phase identification and binding relationship of heavy metals in CSS, and provides novel approaches and theoretical evidence for the CSS and similar smelting slags harmfulness treatment.

The role and its transcriptome mechanisms of cell wall polysaccharides in vanadium detoxication of rice

Cell wall-polysaccharides play a crucial role in heavy metals binding, and hence, contribute to heavy metal detoxication in plants. However, there is no data regarding the molecular mechanisms of vanadium (V) binding to root cell walls in plants, especially in rice (Oryza sativa L.). Taking two rice cultivars with various V tolerance as the research material, the present study investigated the effect of various V concentrations on subcellular distribution of V and revealed the regulatory mechanism of cell wall polysaccharides to V exposure. The results showed that rice roots inhibited the upward movement of V, and root cell walls accumulated 69.85–82.71% of V in roots. Furthermore, hemicellulose-1 (HC-1) in cell walls shared up to 67.72% and 66.95% of the cell-wall-bound V in tolerant and sensitive cultivars, respectively. FTIR spectroscopy demonstrated that V stress induced the remolding of cell wall polysaccharides. Under V stress, V-tolerant rice generated up to 19.3% pectin, 40.9% HC-1, and 49.34% HC-2, which were higher than V-sensitive cultivar. The genes encoding UGDH, UGE, and AXS for polysaccharide biosynthesis were higher expressed in V-tolerant rice than V-sensitive rice when exposed to V. The results could provide novel insight for phytoremediation and food security guarantees.

Extrapolymeric substances (EPS) in Mucilaginibacter rubeus P2 displayed efficient metal(loid) bio-adsorption and production was induced by copper and zinc

Strains of the genus Mucilaginibacter, belonging to the phylum Bacteroidetes, have been noted for exhibiting high genome plasticity and for the vigorous production of extracellular polymeric substances (EPS). Here we analyzed the composition and properties of EPS generated by M. rubeus P2, isolated from a gold-copper mine and exhibiting extremely high resistance to multiple heavy metals. Production of EPS increased significantly upon exposure to elevated concentrations of Cu(II) and Zn(II), but not Au(III). In addition, the EPS produced by M. rubeus P2 displayed extremely high bio-adsorption of As(III), Cu(II) and Au(III), but not of Zn(II). Moreover, EPS production in Mucilaginibacter rubeus P2 exposed to 1 mM of Cu(II) was 8.5 times higher than EPS production in the same strain without metal (loid)-exposure. These findings constitute the basis for a future use of these EPS-overproducing bacteria in bioremediation of heavy metal contaminated environments. The functional groups, especially –SH, CO, and N–H/C–N in the fingerprint zone of glutathione (GSH) and polysaccharides-like components of EPS, were the main components of EPS involved in both Zn(II) and Cu(II) binding and removal. Around 31.22% and 5.74% of Cu(II)-treated EPS was shown to exist as (CO) structures and these structures were converted into C–OH and O–C–O upon exposure to Cu(II), respectively. In contrast, (C–OH/C–O–C/P–O–C) groups in EPS were observed to be positively correlated to increasing concentrations of Zn(II) in strain P2. Furthermore, the complete genome of M. rubeus P2 helped us to identify 350 genes involved in carbohydrate metabolism, some of which are predicted to be involved in EPS production and modification. This work describes the first detailed biochemical and biophysical analysis of EPS from any strain of Mucilaginibacter with unique heavy metal binding properties. The results will be useful for a better understanding of how microorganisms such as M. rubeus P2 adapt to heavy metal polluted environments and how this knowledge can potentially be harnessed in biotechnological applications such as industrial waste water purification, bioremediation of heavy metal contaminated soil and beneficial plant microbe interactions. The toolbox provided in this paper will provide a valuable basis for future studies.

Genetic modifications of metallothionein enhance the tolerance and bioaccumulation of heavy metals in Escherichia coli

Metallothioneins (MTs) are low molecular weight cysteine-rich proteins that bind to metals. Owing to their high cysteine (Cys) content, MTs are effective mediators of heavy metal detoxification. To enhance the heavy metal binding ability of MT from the freshwater crab Sinopotamon henanense (ShMT), sequence-based multiple sequence alignment (MSA) and structure-based molecular docking simulation (MDS) were conducted in order to identify amino acid residues that could be mutated to bolster such metal-binding activity. Site-directed mutagenesis was then used to modify the primary structure of ShMT, and the recombinant proteins were further enhanced using the SUMO fusion expression system to yield SUMO-ShMT1, SUMO-ShMT2, and SUMO-ShMT3 harboring one-, two-, and three- point mutations, respectively. The resultant modified proteins were primarily expressed in a soluble form and exhibited the ability to readily bind to heavy metals. Importantly, these modified proteins exhibited significantly enhanced heavy metal binding capacities, and they improved Cd2+, Cu2+ and Zn2+ tolerance and bioaccumulation in Escherichia coli (E. coli) in a manner dependent upon the number of introduced point mutations (SUMO-ShMT3 > SUMO-ShMT2 > SUMO-ShMT1 > SUMO-ShMT > control). Indeed, E. coli cells harboring the pET28a-SUMO-ShMT3 expression vector exhibited maximal Cd2+, Cu2+, and Zn2+ bioaccumulation that was increased by 1.86 ± 0.02-, 1.71 ± 0.03-, and 2.13 ± 0.02-fold relative to that in E. coli harboring the pET28a-SUMO-ShMT vector. The present study offers a basis for the preparation of genetically engineered bacteria that are better able to bioaccumulate and tolerate heavy metals, thus providing a foundation for biological heavy metal water pollution treatment.

The Effect of Granular Activated Carbon and Biochar on the Availability of Cu and Zn to Hordeum sativum Distichum in Contaminated Soil.

The presence of heavy metals in the soil could impose serious problems on soil-plant systems due to the accumulation of heavy metals in plants. Even vital elements such as Cu and Zn have a toxic effect in the case of excessive intake by living organisms. The present work aimed to investigate the content of loosely bound (exchangeable, complexed, and specifically sorbed) compounds of Cu and Zn and their availability to spring barley (Hordeum sativum distichum) in contaminated Haplic Chernozem soil under the conditions of a model experiment (five approximate permissible concentrations (APC) and 10 APC of metal). Changes in the bioavailability of the metals upon application of carbon sorbents were observed. An increase in loosely bound metal compounds has been shown under conditions of soil contamination with metals (up to 57% of the total content). The increase in the availability of Cu in the soil was mainly due to the formation of complexed metal forms with organic matter (up to 17%). The availability of Zn was found to be associated with an increase in exchangeable (up to 21%) and specifically sorbed compounds (up to 27%). Granular activated carbon (GAC) and biochar have high sorption properties. A decrease in the content of loosely bound compounds of metals was established, especially in the most mobile forms such as exchangeable and complexed forms. The introduction of sorbents into the soil opened up a new venue for binding heavy metals in situ, eventually leading to a decrease in their bioavailability. The inactivation of Cu and Zn in the soil upon the application of sorbents led to a decrease in metal absorption by spring barley. The highest efficiency of biochar application was established at a dose of 2.5% and 5% in soil contaminations of 5 APC and 10 APC of Cu or Zn. The efficiency of the use of sorbents was more influenced by the dose of application than by the type of sorbent. There was no significant difference between biochar and GAC. Stabilization and inactivation of metals may improve soil fertility and plant growth.

Cloning of PCS gene (TpPCS1) from Tagetes patula L. and expression analysis under cadmium stress.

Phytochelatins (PCs) constitute an important mechanism for plants to resist heavy metal stress. Widely found in higher plants, they are small heavy metal binding peptides, synthesized through catalysis of phytochelatin synthase (PCS). We speculate that there may be PCS genes in Peacock grass (Tagetes patula L., Asteraceae), which is an important reason for its rich cadmium. In order to obtain the full-length cDNA sequence of the PCS gene from T. patula L. used rapid amplification of cDNA ends (RACE). Meanwhile, Relative expression of TpPCS1 under different concentrations of cadmium (Cd) stress was analysed using quantitative real-time polymerase chain reaction (qRT-PCR). Results found ORF of TpPCS1 genes with a length of 1970 bp, a gene coding area length of 1764 bp, coding for 587 amino acids. Expression of TpPCS1 under Cd stress was tissue specific. TpPCS1 in the root showed higher expression, while expression in the leaf and seed was relatively low. This research demonstrates that expression of TpPCS1 enhanced the enrichment of cadmium in T. patula L. roots and could be used to construct a plant hyperexpression carrier that would provide new avenues for plant restoration technology.

Assessment of heavy metals in sediments of the Parnaíba River Delta in the semi-arid coast of Brazil

Studies related to heavy metal concentrations in coastal sediments are important to monitor and assess environmental health of estuarine ecosystems. Twenty-eight samples from Parnaiba River Delta, the largest open-ocean delta in the Americas, northeastern of Brazil were tested for heavy metals concentrations (Cd, Cr, Cu, Mn, Ni, Pb, Zn, Al and Fe), grain-size and easily oxidizable carbon. The relations of the heavy metals with sediment composition were evaluated using a multivariate statistical analysis. Sediment pollution assessment was carried out by enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF) and potential ecological risk index (PERI). The average concentrations were 0.50 ± 0.09 mg Cd kg−1, 6.95 ± 2.13 mg Pb kg−1, 19.02 ± 8.75 mg Cu kg−1, 23.20 ± 5.04 mg Ni kg−1, 33.52 ± 6.82 mg Cr kg−1, 43.99 ± 7.47 mg Zn kg−1, 165.73 ± 86.71 mg Mn kg−1, 2.93 ± 0.89% to Fe and 3.78 ± 1.17% to Al. The results indicate lower concentrations of heavy metals relative to limit concentrations defined by the Brazilian regulatory framework. The multivariate analysis reflected the binding of heavy metals to clay minerals and organic carbon. The different geochemical indices indicated sediments minimally enriched by metals and a low potential ecological risk level. Our assessment confirms the pristine conditions of Parnaiba Delta protected area to heavy metal contamination, except Igaracu channel near Parnaiba city.

Simulation of Copper-Dependent Regulation Dynamics in ATP7B

Membrane proteins control the flow of ions across biological membranes by selective import or export and are of vital importance for all living cells. ATP7B is a human P-type ATPase that exports copper from the cytoplasm for excretion or incorporation into proteins, and mutations in ATP7B lead to the copper metabolism disorder Wilson's disease. ATP7B activity is regulated by an N-terminal heavy metal binding domain (HMBD), which is believed to display different dynamics and interaction patterns of its six metal binding domains (MBDs) in response to changes in copper concentration. Because the HMBD is highly dynamic, does not form a compact structure, and contain MBDs that move as rigid bodies with transient copper-dependent interactions, experimental characterization is highly challenging. Despite much effort it is still unknown how the HMBD is arranged around the core protein, and the mechanism of regulation by copper binding is poorly understood. To determine copper-dependent differences in the HMBD structural dynamics, and possible interactions with the core protein, we simulated a homology model of ATP7B in an E2 ion-free state in a membrane environment in the presence and absence of HMBD-bound copper. The results show that the HMBD interacts extensively with the core protein, with distinct differences between the apo and holo state. Specifically, the HMBD adopts more extended conformations in the holo state, with MBD2 and MBD3 showing the greatest differences. The observed results support a regulation mechanism where copper binding results in loss of MBD1-3 interactions as a first step of enzyme activation.

Infectious Diseases and Endocrinology 2019: Some notes about medical applications for microbial biosurfactants - Samer M Al-Hulu- Green University of Al Qasim

Bio-surfactants are amphiphilic biological compounds made extracellular or cell membrane part bacteria, yeast and filamentous fungi. Bio-surfactants are made up of a hydrophilic moiety, may be acid, peptide, action, anion, mono, di or polysaccharides and a hydrophobic moiety, which may be unsaturated or saturated hydrocarbon chains or fatty acids. Many advantages for bio-surfactants comprise biodegradability, low toxicity, biocompatibility and digestivity, presence of raw materials and specificity. The bio-surfactant production was known by many methods includes, hemolytic activity, oil displacement test emulsification index, surface tension reduction, blue agar plate or CTAB agar plate method, hydrocarbon overlay agar method. There are many medial applications for bio-surfactant which includes antimicrobial activity. Biosurfactants having capacity to be toxic on cell membrane permeability in similar method to detergent effect, anti-cancer activity, the neuronal differentiation in PC 12 cells induced by MEL and get ready the ground work for the use of microbial extracellular glycolipids as novel reagents for cancer cell treatment, antiviral activity, the sophorolipids surfactants produce by C. bombicola having structural analogues such as the sophorolipiddiacetate ethyl ester which is powerful spermicidal and virucidal agent and its virucidal activity similar to nonoxynol-9 against the human semen. Anti-adhesive agents, bio-surfactants having capability for adhesion residing for pathogenic organisms to solid surfaces or infection site, anti-fungal activity, flocculosin is a glycolipid produced by yeast like fungus P. flocculosa having antifungal activity against pathogenic yeasts and human mycoses. Immunological adjuvants, bacterial lipo-peptides when mix with classic antigens having active nontoxic, nonpyrogenic immunological adjuvants. Gene delivery, the liposomes based on bio-surfactants having increasing efficiency for gene transfection than cationic liposomes trading use. Microbial compounds that possess pronounced surface and emulsifying activities are categorized as biosurfactants. Biosurfactants include a wide range of chemical structures, such as glycolipids, lipopeptides, polysaccharide–protein complexes, phospholipids, fatty acids and neutral lipids. For instance, Cooper and Goldenberg described different bio emulsifiers produced by two Bacillus species in water-soluble substrates with different emulsifying and surface activities. It is, therefore, reasonable to expect different properties and physiological functions for unique groups of biosurfactants. Moreover, these molecules can be tailor-made to suit different applications by modifying the growth substrate or growth conditions. Although most biosurfactants are regarded to be secondary metabolites, some may play crucial roles for the survival of biosurfactants-producing microorganisms through facilitating nutrient transport or microbe–host interactions or by acting as biocide agents. Biosurfactant roles include increasing the surface area and bioavailability of hydrophobic water-insoluble substrates, heavy metal binding, bacterial pathogenesis, and quorum sensing and biofilm formation. Biosurfactants are amphipathic molecules with both hydrophilic and hydrophobic moieties that partition preferentially at the interface between fluid phases that have different polarity and hydrogen bonding, such as oil and water or air and water interfaces. This property elaborates their wide use in environmental applications. Most work on biosurfactant applications has been focused on their use in environmental applications owing to their diversity, environmentally friendly nature, suitability for large-scale production and selectivity. Despite their potential and biological origin only a few studies have been carried out on applications related to the biomedical field. Some biosurfactants are suitable alternatives to synthetic medicines and antimicrobial agents and may be used as safe and effective therapeutic agents Synthetic surfactants are becoming increasingly unpopular in many areas and applications due to previously disregarded effects on biological systems and this has led to a new focus on replacing such products with biosurfactants that are biodegradable and created from renewal resources. Microbially derived biosurfactants have been investigated in numerous studies in areas including: increasing feed digestibility in an agricultural context, improving seed protection and fertility, plant pathogen control, antimicrobial activity, ant biofilm activity, wound healing and dermatological care, improved oral cavity care, drug delivery systems and anticancer treatments. The development of the potential of biosurfactants has been stopped somewhat by the myriad of steps taken in their investigations, the focus on pathogens as source species and the costs associated with large�?�scale production. Here, we focus on various microbial sources of biosurfactants and the current trends in terms of agricultural and biomedical applications.

Insight into the heavy metal binding properties of dissolved organic matter in mine water affected by water-rock interaction of coal seam goaf

The water-rock interaction has a significant effect on the binding characteristics of dissolved organic matter and heavy metals when mine water flows in goaf. This study used fluorescence excitation-emission matrix (EEM) quenching combined with parallel factor (PARAFAC) analysis to characterize the binding properties of DOM with Fe (Ⅲ), Fe (Ⅱ+Ⅲ) and Mn (Ⅱ) in mine water under rock-influenced conditions. Two protein-like components and two humic-like components were identified by PARAFAC, in which protein-like components dominated (75.9%). The fluorescence intensity of each component can all be weakened, especially the stability constant (logKM) value of Fe (Ⅱ+Ⅲ) with fulvic-like acid and humic-like acid was the largest and the binding was more stable. Clay minerals and iron-bearing minerals in rocks had significant effects on the binding characteristics of DOM and metal ions under water-rock interaction. Iron ions released by the oxidation of pyrite and siderite in sandstone can reduce the fluorescence intensity of the derived components. The competitive adsorption effect of clay minerals on metal ions made the fluorescence intensity of the derived components under the action of sandstone containing less clay minerals (19.5%) be lower than that of mudstone (31.3%). Meanwhile, the process of water-rock interaction was accompanied by microbial activities to convert protein-like components into fulvic-like and humic-like components, or higher levels of stable substances. This study shows that when assessing the potential ability of mine water DOM and metal ions binding and migration during the flow of water in goaf it is crucial to take into account the presence of water-rock interaction.

Extracellular Vesicles and Post-Translational Protein Deimination Signatures in Mollusca-The Blue Mussel (Mytilus edulis), Soft Shell Clam (Mya arenaria), Eastern Oyster (Crassostrea virginica) and Atlantic Jacknife Clam (Ensis leei).

Simple SummaryOysters and clams form an important component of the food chain and food security and are of considerable commercial value worldwide. They are affected by pollution and climate change, as well as a range of infections, some of which are opportunistic. For aquaculture purposes they are furthermore of great commercial value and changes in their immune responses can also serve as indicators of changes in ocean environments. Therefore, studies into understanding new factors in their immune systems may aid new biomarker discovery and are of considerable value. This study assessed new biomarkers relating to changes in protein function in four economically important marine molluscs, the blue mussel, soft shell clam, Eastern oyster, and Atlantic jacknife clam. These findings indicate novel regulatory mechanisms of important metabolic and immunology related pathways in these mollusks. The findings provide new understanding to how these pathways function in diverse ways in different animal species as well as aiding new biomarker discovery for Mollusca aquaculture.Oysters and clams are important for food security and of commercial value worldwide. They are affected by anthropogenic changes and opportunistic pathogens and can be indicators of changes in ocean environments. Therefore, studies into biomarker discovery are of considerable value. This study aimed at assessing extracellular vesicle (EV) signatures and post-translational protein deimination profiles of hemolymph from four commercially valuable Mollusca species, the blue mussel (Mytilus edulis), soft shell clam (Mya arenaria), Eastern oyster (Crassostrea virginica), and Atlantic jacknife clam (Ensis leei). EVs form part of cellular communication by transporting protein and genetic cargo and play roles in immunity and host–pathogen interactions. Protein deimination is a post-translational modification caused by peptidylarginine deiminases (PADs), and can facilitate protein moonlighting in health and disease. The current study identified hemolymph-EV profiles in the four Mollusca species, revealing some species differences. Deiminated protein candidates differed in hemolymph between the species, with some common targets between all four species (e.g., histone H3 and H4, actin, and GAPDH), while other hits were species-specific; in blue mussel these included heavy metal binding protein, heat shock proteins 60 and 90, 2-phospho-D-glycerate hydrolyase, GTP cyclohydrolase feedback regulatory protein, sodium/potassium-transporting ATPase, and fibrinogen domain containing protein. In soft shell clam specific deimination hits included dynein, MCM3-associated protein, and SCRN. In Eastern oyster specific deimination hits included muscle LIM protein, beta-1,3-glucan-binding protein, myosin heavy chain, thaumatin-like protein, vWFA domain-containing protein, BTB domain-containing protein, amylase, and beta-catenin. Deiminated proteins specific to Atlantic jackknife clam included nacre c1q domain-containing protein and PDZ domain-containing protein In addition, some proteins were common as deiminated targets between two or three of the Bivalvia species under study (e.g., EP protein, C1q domain containing protein, histone H2B, tubulin, elongation factor 1-alpha, dominin, extracellular superoxide dismutase). Protein interaction network analysis for the deiminated protein hits revealed major pathways relevant for immunity and metabolism, providing novel insights into post-translational regulation via deimination. The study contributes to EV characterization in diverse taxa and understanding of roles for PAD-mediated regulation of immune and metabolic pathways throughout phylogeny.

Evaluation of Sequential Extraction Procedure (SEP) to Validate Binding Mechanisms in Soils and Soil-Nano-Calcium Silicate (SNCS) Mixtures

The soils in hazardous waste sites contain heavy metals which would leach into groundwater by various biotic and abiotic processes and eventually pose a threat to human health by contaminating the drinking water. In order to understand pattern of heavy metal leachability, the field conditions can be simulated by adopting various types of sequential extraction methods. In this study, an attempt was made to evaluate the effectiveness and selectivity of a sequential extraction process to determine heavy metal binding mechanisms in soils and soil treated with nano-calcium silicate (NCS). A five-step sequential extraction (SE) procedure was adopted on four soils obtained from a sanitary dumpsite, automobile and battery work units from different localities of Bangalore and a steel plant commissioned at Toranagallu, Bellary, India. The soils were mixed with NCS at varying range of 0.5 to 2% by dry weight of the soil. The NCS-amended soils were spiked with cadmium (Cd2+), nickel (Ni2+) and lead (Pb2+) in concentrations to the tune of 3000 mg/kg. It has been observed that there seems to be a gradual increase in binding ability for the targeted heavy metals when soils were amended with NCS compared to untreated soils. This binding phenomenon was attributed to the presence of exchangeable ions, carbonates, oxides of iron and manganese, organic matter and residual fractions. It was noticed that the residual fractions in soils amended with NCS attenuated maximum quantity of metal ions with Pb2+ at 21.46%, followed by 18.8% for Cd2+ and 9.25% for Ni2+ compared to untreated case. Further, this work highlights the role of residual fraction in enhancing the retention capacity of soils by encapsulation of higher concentrations of contaminants. The current study corroborated the fact that the addition of NCS aids in the better encapsulation of selected heavy metal ions.