Displaying publications 1 - 20 of 169 in total

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  1. Jeyaseelan A, Murugesan K, Thayanithi S, Palanisamy SB
    Environ Res, 2024 Mar 15;245:118020.
    PMID: 38151149 DOI: 10.1016/j.envres.2023.118020
    Enhancing crop yield to accommodate the ever-increasing world population has become critical, and diminishing arable land has pressured current agricultural practices. Intensive farming methods have been using more pesticides and insecticides (biocides), culminating in soil deposition, negatively impacting the microbiome. Hence, a deeper understanding of the interaction and impact of pesticides and insecticides on microbial communities is required for the scientific community. This review highlights the recent findings concerning the possible impacts of biocides on various soil microorganisms and their diversity. This review's bibliometric analysis emphasised the recent developments' statistics based on the Scopus document search. Pesticides and insecticides are reported to degrade microbes' structure, cellular processes, and distinct biochemical reactions at cellular and biochemical levels. Several biocides disrupt the relationship between plants and their microbial symbionts, hindering beneficial biological activities that are widely discussed. Most microbial target sites of or receptors are biomolecules, and biocides bind with the receptor through a ligand-based mechanism. The biomarker action mechanism in response to biocides relies on activating the receptor site by specific biochemical interactions. The production of electrophilic or nucleophilic species, free radicals, and redox-reactive agents are the significant factors of biocide's metabolic reaction. Most studies considered for the review reported the negative impact of biocides on the soil microbial community; hence, technological development is required regarding eco-friendly pesticide and insecticide, which has less or no impact on the soil microbial community.
    Matched MeSH terms: Soil/chemistry
  2. Jamion NA, Lee KE, Mokhtar M, Goh TL
    Environ Sci Pollut Res Int, 2024 Mar;31(11):16291-16308.
    PMID: 38315340 DOI: 10.1007/s11356-024-32140-4
    Ex-mining lake-converted constructed wetlands play a significant role in the carbon cycle, offering a great potential to sequester carbon and mitigate climate change and global warming. Investigating the quantity of carbon storage capacity of ex-mining lake-converted constructed wetlands provides information and justification for restoration and conservation efforts. The present study aims to quantify the carbon pool of the ex-mining lake-converted constructed wetlands and characterise the physicochemical properties of the soil and sediment. Pearson's correlation and a one-way ANOVA were performed to compare the different sampling stations at Paya Indah Wetland, Selangor, Malaysia. An analysis of 23 years of ex-mining lake-converted constructed wetlands of Paya Indah Wetlands, Selangor, Malaysia, revealed that the estimated total carbon pool in soil and sediment accumulated to 1553.11 Mg C ha-1 (equivalent to 5700 Mg CO2 ha-1), which translates to an annual carbon sink capacity of around 67.5 Mg C ha-1 year-1. The characterisation showed that the texture of all soil samples was dominated by silt, whereas sediments exhibited texture heterogeneity. Although the pH of the soil and sediment was both acidic, the bulk density was still optimal for plant growth and did not affect root growth. FT-IR and WDXRF results supported that besides the accumulation and degradation of organic substances, which increase the soil and sediment carbon content, mineral carbonation is a mechanism by which soil and sediment can store carbon. Therefore, this study indicates that the ex-mining lake-converted constructed wetlands of Paya Indah Wetlands, Selangor, Malaysia have a significant carbon storage potential.
    Matched MeSH terms: Soil/chemistry
  3. Qutob M, Rafatullah M, Muhammad SA, Alamry KA, Hussein MA
    J Environ Manage, 2024 Feb 27;353:120179.
    PMID: 38295641 DOI: 10.1016/j.jenvman.2024.120179
    Natural soil minerals often contain numerous impurities, resulting in comparatively lower catalytic activity. Tropical soils are viewed as poor from soil organic matter, cations, and anions, which are considered the main impurities in the soil that are restricted to utilizing natural minerals as a catalyst. In this regard, the dissolved iron and hematite crystals that presented naturally in tropical soil were evaluated to activate oxidants and degrade pyrene. The optimum results obtained in this study were 73 %, and the rate constant was 0.0553 h-1 under experimental conditions [pyrene] = 300 mg/50 g, pH = 7, T = 55 °C, airflow = 260 mL/min, [Persulfate (PS)] = 1.0 g/L, and humic acid (HA) ( % w/w) = 0.5 %. The soil characterization analysis after the remediation process showed an increase in moieties and cracks of the soil aggregate, and a decline in the iron and aluminium contents. The scavengers test revealed that both SO4•- and O2•- were responsible for the pyrene degradation, while HO• had a minor role in the degradation process. In addition, the monitoring of by-products, degradation pathways, and toxicity assessment were also investigated. This system is considered an efficient, green method, and could provide a step forward to develop low-cost soil remediation for full-scale implementation.
    Matched MeSH terms: Soil/chemistry
  4. Han L, Gu H, Lu W, Li H, Peng WX, Ling Ma N, et al.
    Chemosphere, 2023 Dec;344:140307.
    PMID: 37769918 DOI: 10.1016/j.chemosphere.2023.140307
    As chromium (Cr) in ecosystems affects human health through food chain exposure, phytoremediation is an environmentally friendly and efficient way to reduce chromium pollution in the environment. Here, we review the mechanism of absorption, translocation, storage, detoxification, and regulation of Cr in plants. The Cr(VI) form is more soluble, mobile, and toxic than Cr(III), reflecting how various valence states of Cr affect environmental risk characteristics, physicochemical properties, toxicity, and plant uptake. Plant root's response to Cr exposure leads to reactive oxygen species (ROS) generation and apoptosis. Cell wall immobilization, vacuole compartmentation, interaction of defense proteins and organic ligand with Cr, and removal of reactive oxygen species by antioxidants continue plant life. In addition, the combined application of microorganisms, genetic engineering, and the addition of organic acids, nanoparticles, fertilization, soil amendments, and other metals could accelerate the phytoremediation process. This review provides efficient methods to investigate and understand the complex changes of Cr metabolism in plants. Preferably, fast-growing, abundantly available biomass species should be modified to mitigate Cr pollution in the environment as these green and efficient remediation technologies are necessary for the protection of soil and water ecology.
    Matched MeSH terms: Soil/chemistry
  5. Gu H, Yan J, Liu Y, Yu X, Feng Y, Yang X, et al.
    Environ Res, 2023 May 01;224:115543.
    PMID: 36822540 DOI: 10.1016/j.envres.2023.115543
    Bioaugmentation helps to obtain a microbiome capable of remediating polycyclic aromatic hydrocarbons (PAHs). In this study, acclimation of microorganisms to soil supplemented with phenanthrene (PHE) led to enrichment with PAH-degraders, including those in Actinobacteriota and in the genera Streptomyces, Rhodococcus, Nocardioides, Sphingomonas, and Mycobacterium. Aqueous (28 °C, pH 6.5) and soil cultures inoculated with PHE-acclimated soil showed a high PHE (ca. 50 mg L-1) degradation efficiency. The PHE degradation kinetics in aqueous and soil incubations fitted to the Gompertz equation and the first-order kinetic equation, respectively. Indigenous microorganisms adapted to PHE in their environment, and this increased their capacity to degrade PHE. The effect of co-contaminants and pathway intermediates on PHE degradation showed that the degradation of PHE improved in the presence of diesel while being hindered by lubricant oil, catechol, salicylic and phthalic acid. Our findings provide theoretical and practical support for bioremediationof PAHs in the environment.
    Matched MeSH terms: Soil/chemistry
  6. Saeed M, Ilyas N, Bibi F, Shabir S, Jayachandran K, Sayyed RZ, et al.
    Chemosphere, 2023 May;324:138311.
    PMID: 36878368 DOI: 10.1016/j.chemosphere.2023.138311
    A novel kinetic model has been developed to explain the degradation of total petroleum hydrocarbons. Microbiome engineered biochar amendment may result in a synergistic impact on degradation of total petroleum hydrocarbons (TPHs). Therefore, the present study analyzed the potential of hydrocarbon-degrading bacteria A designated as Aeromonas hydrophila YL17 and B as Shewanella putrefaciens Pdp11 morphological characterized as rod shaped, anaerobic and gram-negative immobilized on biochar, and the degradation efficiency was measured by gravimetric analysis and gas chromatography-mass spectrometry (GC-MS). Whole genome sequencing of both strains revealed the existence of genes responsible for hydrocarbon degradation. In 60 days remediation setup, the treatment consisting of immobilization of both strains on biochar proved more efficient with less half-life and better biodegradation potentials compared to biochar without strains for decreasing the content of TPHs and n-alkanes (C12-C18). Enzymatic content and microbiological respiration showed that biochar acted as a soil fertilizer and carbon reservoir and enhanced microbial activities. The removal efficiency of hydrocarbons was found to be a maximum of 67% in soil samples treated with biochar immobilized with both strains (A + B), followed by biochar immobilized with strain B 34%, biochar immobilized with strain A 29% and with biochar 24%, respectively. A 39%, 36%, and 41% increase was observed in fluorescein diacetate (FDA) hydrolysis, polyphenol oxidase and dehydrogenase activities in immobilized biochar with both strains as compared to control and individual treatment of biochar and strains. An increase of 35% was observed in the respiration rate with the immobilization of both strains on biochar. While a maximum colony forming unit (CFU/g) was found 9.25 with immobilization of both strains on biochar at 40 days of remediation. The degradation efficiency was due to synergistic effect of both biochar and bacteria based amendment on the soil enzymatic activity and microbial respiration.
    Matched MeSH terms: Soil/chemistry
  7. Kurniawan TA, Othman MHD, Liang X, Goh HH, Gikas P, Chong KK, et al.
    J Environ Manage, 2023 Apr 15;332:117429.
    PMID: 36773474 DOI: 10.1016/j.jenvman.2023.117429
    Biochar, derived from unused biomass, is widely considered for its potential to deal with climate change problems. Global interest in biochar is attributed to its ability to sequester carbon in soil and to remediate aquatic environment from water pollution. As soil conditioner and/or adsorbent, biochar offers opportunity through a circular economy (CE) paradigm. While energy transition continues, progress toward low-emissions materials accelerates their advance towards net-zero emissions. However, none of existing works addresses CE-based biochar management to achieve carbon neutrality. To reflect its novelty, this work provides a critical overview of challenges and opportunities for biochar to promote CE and carbon neutrality. This article also offers seminal perspectives about strengthening biomass management through CE and resource recovery paradigms, while exploring how the unused biomass can promote net zero emissions in its applications. By consolidating scattered knowledge in the body of literature into one place, this work uncovers new research directions to close the loops by implementing the circularity of biomass resources in various fields. It is conclusive from a literature survey of 113 articles (2003-2023) that biomass conversion into biochar can promote net zero emissions and CE in the framework of the UN Sustainable Development Goals (SDGs). Depending on their physico-chemical properties, biochar can become a suitable feedstock for CE. Biochar application as soil enrichment offsets 12% of CO2 emissions by land use annually. Adding biochar to soil can improve its health and agricultural productivity, while minimizing about 1/8 of CO2 emissions. Biochar can also sequester CO2 in the long-term and prevent the release of carbon back into the atmosphere after its decomposition. This practice could sequester 2.5 gigatons (Gt) of CO2 annually. With the global biochar market reaching USD 368.85 million by 2028, this work facilitates biochar with its versatile characteristics to promote carbon neutrality and CE applications.
    Matched MeSH terms: Soil/chemistry
  8. Li G, Yan L, Chen X, Lam SS, Rinklebe J, Yu Q, et al.
    Chemosphere, 2023 Apr;320:138058.
    PMID: 36746249 DOI: 10.1016/j.chemosphere.2023.138058
    Potentially toxic elements (PTEs) pose a great threat to ecosystems and long-term exposure causes adverse effects to wildlife and humans. Cadmium induces a variety of diseases including cancer, kidney dysfunction, bone lesions, anemia and hypertension. Here we review the ability of plants to accumulate cadmium from soil, air and water under different environmental conditions, focusing on absorption mechanisms and factors affecting these. Cadmium possess various transport mechanisms and pathways roughly divided into symplast and apoplast pathway. Excessive cadmium concentrations in the environment affects soil properties, pH and microorganism composition and function and thereby plant uptake. At the same time, plants resist cadmium toxicity by antioxidant reaction. The differences in cadmium absorption capacity of plants need more exploration to determine whether it is beneficial for crop breeding or genetic modification. Identify whether plants have the potential to become hyperaccumulator and avoid excessive cadmium uptake by edible plants. The use of activators such as wood vinegar, GLDA (Glutamic acid diacetic acid), or the placement of earthworms and fungi can speed up phytoremediation of plants, thereby reducing uptake of crop varieties and reducing human exposure, thus accelerating food safety and the health of the planet.
    Matched MeSH terms: Soil/chemistry
  9. Siraz MMM, Roy D, Dewan MJ, Alam MS, A M J, Rashid MB, et al.
    Environ Monit Assess, 2023 Feb 10;195(3):382.
    PMID: 36759352 DOI: 10.1007/s10661-023-10921-7
    This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg-1, 19.69 ± 2.15 Bqkg-1, and 347.82 ± 24.50 Bqkg-1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.
    Matched MeSH terms: Soil/chemistry
  10. Peng Y, Fornara DA, Wu Q, Heděnec P, Yuan J, Yuan C, et al.
    Sci Total Environ, 2023 Jan 20;857(Pt 3):159686.
    PMID: 36302428 DOI: 10.1016/j.scitotenv.2022.159686
    Plant litter decomposition is not only the major source of soil carbon and macronutrients, but also an important process for the biogeochemical cycling of trace elements such as iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). The concentrations of plant litter trace elements can influence litter decomposition and element cycling across the plant and soil systems. Yet, a global perspective of the patterns and driving factors of trace elements in plant litter is missing. To bridge this knowledge gap, we quantitatively assessed the concentrations of four common trace elements, namely Fe, Mn, Zn, and Cu, of freshly fallen plant litter with 1411 observations extracted from 175 publications across the globe. Results showed that (1) the median of the average concentrations of litter Fe, Mn, Zn, and Cu were 0.200, 0.555, 0.032, and 0.006 g/kg, respectively, across litter types; (2) litter concentrations of Fe, Zn, and Cu were generally stable regardless of variations in multiple biotic and abiotic factors (e.g., plant taxonomy, climate, and soil properties); and (3) litter Mn concentration was more sensitive to environmental conditions and influenced by multiple factors, but mycorrhizal association and soil pH and nitrogen concentration were the most important ones. Overall, our study provides a clear global picture of plant litter Fe, Mn, Zn, and Cu concentrations and their driving factors, which is important for improving our understanding on their biogeochemical cycling along with litter decomposition processes.
    Matched MeSH terms: Soil/chemistry
  11. Mehmood S, Ilyas N, Akhtar N, Chia WY, Shati AA, Alfaifi MY, et al.
    Environ Res, 2023 Jan 15;217:114784.
    PMID: 36395868 DOI: 10.1016/j.envres.2022.114784
    Vast amounts of plastic waste are causing serious environmental issues and urge to develop of new remediation methods. The aim of the study is to determine the role of inorganic (nitric acid), organic (starch addition), and biological (Pseudomonas aeruginosa) soil amendments on the degradation of Polyethylene (PE) and phytotoxic assessment for the growth of lettuce plant. The PE-degrading bacteria were isolated from the plastic-contaminated soil. The strain was identified as Pseudomonas aeruginosa (OP007126) and showed the highest degradation percentage for PE. PE was pre-treated with nitric acid as well as starch and incubated in the soil, whereas P. aeruginosa was also inoculated in PE-contaminated soils. Different combinations were also tested. FTIR analysis and weight reduction showed that though nitric acid was efficient in degradation, the combined application of starch and bacteria also showed effective degradation of PE. Phytotoxicity was assessed using morphological, physiological, and biochemical parameters of plant. Untreated PE significantly affected plants' physiology, resulting in a 45% reduction in leaf chlorophyll and a 40% reduction in relative water content. It also had adverse effects on the biochemical parameters of lettuce. Bacterial inoculation and starch treatment mitigated the harmful impact of stress and improved plants' growth as well as physiological and biochemical parameters; however, the nitric treatment proved phytotoxic. The observed results revealed that bacteria and starch could be effectively used for the degradation of pre-treated PE.
    Matched MeSH terms: Soil/chemistry
  12. Ahmad MF, Abdullah H, Hassan MN, Jamaludin MI, Sivam A, Komatsu K, et al.
    Int J Mol Sci, 2023 Jan 03;24(1).
    PMID: 36614337 DOI: 10.3390/ijms24010872
    Soil ecosystems are home to a diverse range of microorganisms, but they are only partially understood because no single-cell sequencing or whole-community sequencing provides a complete picture of these complex communities. Using one of such metagenomics approaches, we succeeded in monitoring the microbial diversity and stress-response gene in the soil samples. This study aims to test whether known differences in taxonomic diversity and composition are reflected in functional gene profiles by implementing whole gene sequencing (WGS) metagenomic analysis of geographically dispersed soils from two distinct pristine forests. The study was commenced by sequencing three rainforest soil samples and three peat swamp soil samples. Soil richness effects were assessed by exploring the changes in specific functional gene abundances to elucidate physiological constraints acting on different soil systems and identify variance in functional pathways relevant to soil biogeochemical cycling. Proteobacteria shows abundances of microbial diversity for 52.15% in Royal Belum Reserved Forest and 48.28% in Raja Musa; 177 out of 1,391,841 and 449 out of 3,586,577 protein coding represent acidic stress-response genes for Royal Belum and Raja Musa, respectively. Raja Musa indicates pH 2.5, which is extremely acidic. The analysis of the taxonomic community showed that Royal Belum soils are dominated by bacteria (98% in Sungai Kooi (SK), 98% in Sungai Papan (SP), and 98% in Sungai Ruok (SR), Archaea (0.9% in SK, 0.9% in SP, and 1% in SR), and the remaining were classed under Eukaryota and viruses. Likewise, the soils of Raja Muda Musa are also dominated by bacteria (95% in Raja Musa 1 (RM1), 98% in Raja Musa 2 (RM2), and 96% in Raja Musa 3 (RM3)), followed by Archaea (4% in RM1, 1% in RM2, and 3% in RM3), and the remaining were classed under Eukaryota and viruses. This study revealed that RBFR (Royal Belum Foresr Reserve) and RMFR (Raja Musa Forest Reserve) metagenomes contained abundant stress-related genes assigned to various stress-response pathways, many of which did not show any difference among samples from both sites. Our findings indicate that the structure and functional potential of the microbial community will be altered by future environmental potential as the first glimpse of both the taxonomic and functional composition of soil microbial communities.
    Matched MeSH terms: Soil/chemistry
  13. Brown C, Boyd DS, Sjögersten S, Vane CH
    PLoS One, 2023;18(3):e0280187.
    PMID: 36989287 DOI: 10.1371/journal.pone.0280187
    Tropical peatlands are important carbon stores that are vulnerable to drainage and conversion to agriculture. Protection and restoration of peatlands are increasingly recognised as key nature based solutions that can be implemented as part of climate change mitigation. Identification of peatland areas that are important for protection and restauration with regards to the state of their carbon stocks, are therefore vital for policy makers. In this paper we combined organic geochemical analysis by Rock-Eval (6) pyrolysis of peat collected from sites with different land management history and optical remote sensing products to assess if remotely sensed data could be used to predict peat conditions and carbon storage. The study used the North Selangor Peat Swamp forest, Malaysia, as the model system. Across the sampling sites the carbon stocks in the below ground peat was ca 12 times higher than the forest (median carbon stock held in ground vegetation 114.70 Mg ha-1 and peat soil 1401.51 Mg ha-1). Peat core sub-samples and litter collected from Fire Affected, Disturbed Forest, and Managed Recovery locations (i.e. disturbed sites) had different decomposition profiles than Central Forest sites. The Rock-Eval pyrolysis of the upper peat profiles showed that surface peat layers at Fire Affected, Disturbed Forest, and Managed Recovery locations had lower immature organic matter index (I-index) values (average I-index range in upper section 0.15 to -0.06) and higher refractory organic matter index (R -index) (average R-index range in upper section 0.51 to 0.65) compared to Central Forest sites indicating enhanced decomposition of the surface peat. In the top 50 cm section of the peat profile, carbon stocks were negatively related to the normalised burns ratio (NBR) (a satellite derived parameter) (Spearman's rho = -0.664, S = 366, p-value = <0.05) while there was a positive relationship between the hydrogen index and the normalised burns ratio profile (Spearman's rho = 0.7, S = 66, p-value = <0.05) suggesting that this remotely sensed product is able to detect degradation of peat in the upper peat profile. We conclude that the NBR can be used to identify degraded peatland areas and to support identification of areas for conversation and restoration.
    Matched MeSH terms: Soil/chemistry
  14. Jamil FN, Hashim AM, Yusof MT, Saidi NB
    Mycologia, 2023;115(2):178-186.
    PMID: 36893072 DOI: 10.1080/00275514.2023.2180975
    Banana (Musa spp.), an important food crop in many parts of the world, is threatened by a deadly wilt disease caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (TR4). Increasing evidence indicates that plant actively recruits beneficial microbes in the rhizosphere to suppress soil-borne pathogens. Hence, studies on the composition and diversity of the root-associated microbial communities are important for banana health. Research on beneficial microbial communities has focused on bacteria, although fungi can also influence soil-borne disease. Here, high-throughput sequencing targeting the fungal internal transcribed spacer (ITS) was employed to systematically characterize the difference in the soil fungal community associated with Fusarium wilt (FW) of banana. The community structure of fungi in the healthy and TR4-infected rhizospheres was significantly different compared with that of bulk soil within the same farm. The rhizosphere soils of infected plants exhibited higher richness and diversity compared with healthy plants, with significant abundance of Fusarium genus at 14%. In the healthy rhizosphere soil, Penicillium spp. were more abundant at 7% and positively correlated with magnesium. This study produced a detailed description of fungal community structure in healthy and TR4-infected banana soils in Malaysia and identified candidate biomarker taxa that may be associated with FW disease promotion and suppression. The findings also expand the global inventory of fungal communities associated with the components of asymptomatic and symptomatic banana plants infected by TR4.
    Matched MeSH terms: Soil/chemistry
  15. Jamil FN, Hashim AM, Yusof MT, Saidi NB
    Sci Rep, 2022 Jan 19;12(1):999.
    PMID: 35046475 DOI: 10.1038/s41598-022-04886-9
    Fusarium wilt (FW) caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (TR4) is a soil-borne disease that infects bananas, causing severe economic losses worldwide. To reveal the relationship between bacterial populations and FW, the bacterial communities of healthy and TR4-infected rhizosphere and bulk soils were compared using 16S rRNA gene sequencing. Soil physicochemical properties associated with FW were also analyzed. We found the community structure of bacteria in the healthy and TR4 infected rhizosphere was significantly different compared to bulk soil within the same farm. The rhizosphere soils of infected plants exhibited higher richness and diversity than healthy plant with significant abundance of Proteobacteria. In the healthy rhizosphere soil, beneficial bacteria such as Burkholderia and Streptomyces spp. were more abundant. Compared to the infected rhizosphere soil, healthy rhizosphere soil was associated with RNA metabolism and transporters pathways and a high level of magnesium and cation exchange capacity. Overall, we reported changes in the key taxa of rhizospheric bacterial communities and soil physicochemical properties of healthy and FW-infected plants, suggesting their potential role as indicators for plant health.
    Matched MeSH terms: Soil/chemistry*
  16. Azmi NN, Mahyudin NA, Wan Omar WH, Mahmud Ab Rashid NK, Ishak CF, Abdullah AH, et al.
    Molecules, 2021 Dec 28;27(1).
    PMID: 35011396 DOI: 10.3390/molecules27010170
    Natural clays have recently been proven to possess antibacterial properties. Effective natural antimicrobial agents are needed to combat bacterial contamination on food contact surfaces, which are increasingly more prevalent in the food chain. This study sought to determine the antibacterial activity of clays against the food-borne pathogens Salmonella typhimurium ATCC 14028 and Staphylococcus aureus ATCC 13565. Soils were processed to yield leachates and suspensions from untreated and treated clays. Soil particle size, pH, cation-exchange capacity, metal composition and mineralogy were characterized. Antibacterial screening was performed on six Malaysian soils via the disc diffusion method. In addition, a time-kill assay was conducted on selected antibacterial clays after 6 h of exposure. The screening revealed that Munchong and Carey clays significantly inhibit Salmonella typhimurium (11.00 ± 0.71 mm) and S. aureus (7.63 ± 0.48 mm), respectively. Treated Carey clay leachate and suspension completely kill Salmonella typhimurium, while S. aureus viability is reduced (2 to 3 log10). The untreated Carey and all Munchong clays proved ineffective as antibacterials. XRD analysis confirmed the presence of pyrite and magnetite. Treated Carey clays had a higher soluble metal content compared to Munchong; namely Al (92.63 ± 2.18 mg/L), Fe (65.69 ± 3.09 mg/L) and Mg (88.48 ± 2.29 mg/L). Our results suggest that metal ion toxicity is responsible for the antibacterial activity of these clays.
    Matched MeSH terms: Soil/chemistry*
  17. van der Ent A, Nkrumah PN, Aarts MGM, Baker AJM, Degryse F, Wawryk C, et al.
    BMC Plant Biol, 2021 Sep 27;21(1):437.
    PMID: 34579652 DOI: 10.1186/s12870-021-03190-4
    BACKGROUND: Some subspecies of Dichapetalum gelonioides are the only tropical woody zinc (Zn)-hyperaccumulator plants described so far and the first Zn hyperaccumulators identified to occur exclusively on non-Zn enriched 'normal' soils. The aim of this study was to investigate Zn cycling in the parent rock-soil-plant interface in the native habitats of hyperaccumulating Dichapetalum gelonioides subspecies (subsp. pilosum and subsp. sumatranum). We measured the Zn isotope ratios (δ66Zn) of Dichapetalum plant material, and associated soil and parent rock materials collected from Sabah (Malaysian Borneo).

    RESULTS: We found enrichment in heavy Zn isotopes in the topsoil (δ66Zn 0.13 ‰) relative to deep soil (δ66Zn -0.15 ‰) and bedrock (δ66Zn -0.90 ‰). This finding suggests that both weathering and organic matter influenced the Zn isotope pattern in the soil-plant system, with leaf litter cycling contributing significantly to enriched heavier Zn in topsoil. Within the plant, the roots were enriched in heavy Zn isotopes (δ66Zn ~ 0.60 ‰) compared to mature leaves (δ66Zn ~ 0.30 ‰), which suggests highly expressed membrane transporters in these Dichapetalum subspecies preferentially transporting lighter Zn isotopes during root-to-shoot translocation. The shoots, mature leaves and phloem tissues were enriched in heavy Zn isotopes (δ66Zn 0.34-0.70 ‰) relative to young leaves (δ66Zn 0.25 ‰). Thisindicates that phloem sources are enriched in heavy Zn isotopes relative to phloem sinks, likely because of apoplastic retention and compartmentalization in the Dichapetalum subspecies.

    CONCLUSIONS: The findings of this study reveal Zn cycling in the rock-soil-plant continuum within the natural habitat of Zn hyperaccumulating subspecies of Dichapetalum gelonioides from Malaysian Borneo. This study broadens our understanding of the role of a tropical woody Zn hyperaccumulator plant in local Zn cycling, and highlights the important role of leaf litter recycling in the topsoil Zn budget. Within the plant, phloem plays key role in Zn accumulation and redistribution during growth and development. This study provides an improved understanding of the fate and behaviour of Zn in hyperaccumulator soil-plant systems, and these insights may be applied in the biofortification of crops with Zn.

    Matched MeSH terms: Soil/chemistry*
  18. Maru A, Ahmed OH, Primus WC, Jeffary AV
    Sci Rep, 2021 06 15;11(1):12545.
    PMID: 34131184 DOI: 10.1038/s41598-021-91426-6
    Unbalanced utilization of nitrogen (N) rice not economically viable neither is this practice environmental friendly. Co-application of biochar and urea could reduce the unbalanced use of this N fertilizer in rice cultivation. Thus, a field study was carried out to: (i) determine the effects of chicken litter biochar and urea fertilization on N concentration in soil solution of a cultivated rice (MR219) using dielectric measurement at a low frequency and (ii) correlate soil dielectric conductivity with rice grain yield at maturity. Dielectric response of the soil samples at 20, 40, 55, and 75 days after transplanting were determined using an inductance-capacitance-resistance meter HIOKI 3522-50 LCR HiTESTER. Selected soil chemical properties and yield were determined using standard procedures. The dielectric conductivity and permittivity of the soil samples measured before transplanting the rice seedlings were higher than those for the soil samples after transplanting. This was due to the inherent nitrogen of the chicken litter biochar and the low nitrogen uptake at the transplanting stage. The soil N response increased with increasing measurement frequency and N concentration. The permittivity of the soil samples was inversely proportional to frequency but directly proportional to N concentration in the soil solution. The estimated contents of N in the soil using the dielectric conductivity approach at 1000 Hz decreased with increasing days of fertilization and the results were similar to those of soil NH4+ determined using chemical analysis. The conductivity measured within 1000 Hz and 100,000 Hz correlated positively with the rice grain yield suggesting that nitrogen concentration of the soil can be used to estimate grain yield of the cultivated rice plants.
    Matched MeSH terms: Soil/chemistry*
  19. Heo CC, Tomberlin JK, Aitkenhead-Peterson JA
    J Forensic Sci, 2021 May;66(3):947-959.
    PMID: 33290606 DOI: 10.1111/1556-4029.14645
    Under normal circumstances, insects such as blow flies will oviposit and larvae will colonize a carcass as soon as possible. However, insect colonization on a carcass may be delayed due to the effects of wrapping, shallow burial, addition of lime derivatives to mitigate scavenging and odor, or extreme weather. The impacts of delayed insect colonization on carcass decomposition and its subsequent effect on soil chemistry profiles have not been examined to date. The objectives of this study were to determine soil chemistry dynamics associated with porcine carcasses experiencing delayed insect colonization for 7-day or 14-day. Soil chemistry profiles such as ammonium-N (NH4 -N), orthophosphate-P (PO4 -P), and dissolved organic carbon (DOC) were significantly different among treatments: insect inclusion (immediate access of blow fly colonization on porcine carcasses), 7-day insect exclusion and 14-day insect exclusion (blow fly access was delayed up to 7-day and 14-day). Furthermore, significant differences of soil chemical profiles were detected between days of decomposition and soil regions. Soil moisture, NH4 -N, PO4 -P, and DOC were significantly higher when insects were excluded from the porcine carcass suggesting loss of tissue from larval feeding reduced the mass of nutrients entering the soil. This study provides useful information for forensic science in cases where insect colonization is delayed for a period of time postmortem and soil chemistry in the cadaver decomposition island is considered for estimating postmortem interval.
    Matched MeSH terms: Soil/chemistry*
  20. Dom SP, Ikenaga M, Lau SYL, Radu S, Midot F, Yap ML, et al.
    Sci Rep, 2021 Mar 19;11(1):6416.
    PMID: 33742002 DOI: 10.1038/s41598-021-81865-6
    Tropical peat swamp forest is a global store of carbon in a water-saturated, anoxic and acidic environment. This ecosystem holds diverse prokaryotic communities that play a major role in nutrient cycling. A study was conducted in which a total of 24 peat soil samples were collected in three forest types in a tropical peat dome in Sarawak, Malaysia namely, Mixed Peat Swamp (MPS), Alan Batu (ABt), and Alan Bunga (ABg) forests to profile the soil prokaryotic communities through meta 16S amplicon analysis using Illumina Miseq. Results showed these ecosystems were dominated by anaerobes and fermenters such as Acidobacteria, Proteobacteria, Actinobacteria and Firmicutes that cover 80-90% of the total prokaryotic abundance. Overall, the microbial community composition was different amongst forest types and depths. Additionally, this study highlighted the prokaryotic communities' composition in MPS was driven by higher humification level and lower pH whereas in ABt and ABg, the less acidic condition and higher organic matter content were the main factors. It was also observed that prokaryotic diversity and abundance were higher in the more oligotrophic ABt and ABg forest despite the constantly waterlogged condition. In MPS, the methanotroph Methylovirgula ligni was found to be the major species in this forest type that utilize methane (CH4), which could potentially be the contributing factor to the low CH4 gas emissions. Aquitalea magnusonii and Paraburkholderia oxyphila, which can degrade aromatic compounds, were the major species in ABt and ABg forests respectively. This information can be advantageous for future study in understanding the underlying mechanisms of environmental-driven alterations in soil microbial communities and its potential implications on biogeochemical processes in relation to peatland management.
    Matched MeSH terms: Soil/chemistry*
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