Expanding applications of metal-based nanoparticles (NPs) in industry and agriculture have influenced agro-ecosystems. However, relatively little is known about the bioaccumulation, distribution, and ...phytotoxicity of ZnO-NPs, CuO-NPs, ZnO-bulk, CuO-bulk, Zn2+, or Cu2+ in maize. Plants were exposed to 0.05–2 mg ml−1 or g−1 of six tested materials in agar (7 days) in hydroponic medium (20 days), or sandy-clay-loam soil (20 or 40 days). Seed germination, emergence and lengths of plumules, principal and seminal roots were significantly inhibited by ZnO-NPs, CuO-NPs, Zn2+, and Cu2+. Toxicity was more pronounced in hydroponic culture than in soil, and perceptible alterations in biomolecules were evident. ICP-MS analysis exhibited progressive uptake of metals while morphological, elemental, and surface/deeper scanning showed translocation and distribution of NPs in tissues. Tested materials induced enhanced superoxide radical production, lipid peroxidation, and antioxidant enzymes and proline levels. Exposure significantly reduced P-accumulation, photosynthesis, and protein production. Zn2+ and Cu2+ were found to be more toxic than NPs. Compared to 20 days exposure in soil, toxicity slightly increased after 40 days. ZnO-NPs and CuO-NPs increased apoptotic sub-G1 population by 22.4% and 38%, respectively. These results provide a better understanding of the mechanistic aspects responsible for the nanotoxicities of ZnO- and CuO-NPs in maize.
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•The influences of six test materials on maize physiology in hydroponic and soil are studied.•CuO-NPs/ZnO-NPs deeply penetrate, translocate and are distributed throughout the plants.•Toxicity is higher in agar or hydroponic media than sandy-clay-loam soil.•Nanoparticles induce apoptosis, oxidative stress, proline levels, and lipid peroxidation.•P-accumulation, photosynthesis, and protein production are severely reduced.
Some microbes display pleomorphism, showing variable cell shapes in a single culture, whereas others differentiate to adapt to changed environmental conditions. The pleomorphic archaeon
commonly ...forms discoid-shaped ('plate') cells in culture, but may also be present as rods, and can develop into motile rods in soft agar, or longer filaments in certain biofilms. Here we report improvement of
growth in both semi-defined and complex media by supplementing with eight trace element micronutrients. With these supplemented media, transient development of plate cells into uniformly shaped rods was clearly observed during the early log phase of growth; cells then reverted to plates for the late log and stationary phases. In media prepared with high-purity water and reagents, without supplemental trace elements, rods and other complex elongated morphologies ('pleomorphic rods') were observed at all growth stages of the culture; the highly elongated cells sometimes displayed a substantial tubule at one or less frequently both poles, as well as unusual tapered and highly curved forms. Polar tubules were observed forming by initial mid-cell narrowing or tubulation, causing a dumbbell-like shape, followed by cell division towards one end. Formation of the uniform early log-phase rods, as well as the pleomorphic rods and tubules were dependent on the function of the tubulin-like cytoskeletal protein, CetZ1. Our results reveal the remarkable morphological plasticity of
cells in response to multiple culture conditions, and should facilitate the use of this species in further studies of archaeal biology.
Stem cells: past, present, and future Zakrzewski, Wojciech; Dobrzyński, Maciej; Szymonowicz, Maria ...
Stem cell research & therapy,
02/2019, Letnik:
10, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In recent years, stem cell therapy has become a very promising and advanced scientific research topic. The development of treatment methods has evoked great expectations. This paper is a review ...focused on the discovery of different stem cells and the potential therapies based on these cells. The genesis of stem cells is followed by laboratory steps of controlled stem cell culturing and derivation. Quality control and teratoma formation assays are important procedures in assessing the properties of the stem cells tested. Derivation methods and the utilization of culturing media are crucial to set proper environmental conditions for controlled differentiation. Among many types of stem tissue applications, the use of graphene scaffolds and the potential of extracellular vesicle-based therapies require attention due to their versatility. The review is summarized by challenges that stem cell therapy must overcome to be accepted worldwide. A wide variety of possibilities makes this cutting edge therapy a turning point in modern medicine, providing hope for untreatable diseases.
Summary
Low‐phosphate (Pi) conditions are known to repress primary root growth of Arabidopsis at low pH and in an Fe‐dependent manner. This growth arrest requires accumulation of the transcription ...factor STOP1 in the nucleus, where it activates the transcription of the malate transporter gene ALMT1; exuded malate is suspected to interact with extracellular Fe to inhibit root growth. In addition, ALS3 – an ABC‐like transporter identified for its role in tolerance to toxic Al – represses nuclear accumulation of STOP1 and the expression of ALMT1. Until now it was unclear whether Pi deficiency itself or Fe activates the accumulation of STOP1 in the nucleus. Here, by using different growth media to dissociate the effects of Fe from Pi deficiency itself, we demonstrate that Fe is sufficient to trigger the accumulation of STOP1 in the nucleus, which, in turn, activates the expression of ALMT1. We also show that a low pH is necessary to stimulate the Fe‐dependent accumulation of nuclear STOP1. Furthermore, pharmacological experiments indicate that Fe inhibits proteasomal degradation of STOP1. We also show that Al acts like Fe for nuclear accumulation of STOP1 and ALMT1 expression, and that the overaccumulation of STOP1 in the nucleus of the als3 mutant grown in low‐Pi conditions could be abolished by Fe deficiency. Altogether, our results indicate that, under low‐Pi conditions, Fe2/3+ and Al3+ act similarly to increase the stability of STOP1 and its accumulation in the nucleus where it activates the expression of ALMT1.
Significance Statement
Low‐phosphate, low‐pH and excess aluminum are three major stresses inhibiting root growth. The Arabidopsis transcription factor STOP1 has a major role in root growth under these different stresses, but how STOP1 is regulated is not known. Here we show that Fe –instead of low‐phosphate– and Al promote the accumulation of STOP1 in root nuclei, in a low‐pH‐dependent manner. This work unveils an important regulatory step in the response to Al and Fe stresses.
Zeolite catalysts and adsorbents have been an integral part of many commercial processes and are projected to play a significant role in emerging technologies to address the changing energy and ...environmental landscapes. The ability to rationally design zeolites with tailored properties relies on a fundamental understanding of crystallization pathways to strategically manipulate processes of nucleation and growth. The complexity of zeolite growth media engenders a diversity of crystallization mechanisms that can manifest at different synthesis stages. In this review, we discuss the current understanding of classical and nonclassical pathways associated with the formation of (alumino)silicate zeolites. We begin with a brief overview of zeolite history and seminal advancements, followed by a comprehensive discussion of different classes of zeolite precursors with respect to their methods of assembly and physicochemical properties. The following two sections provide detailed discussions of nucleation and growth pathways wherein we emphasize general trends and highlight specific observations for select zeolite framework types. We then close with conclusions and future outlook to summarize key hypotheses, current knowledge gaps, and potential opportunities to guide zeolite synthesis toward a more exact science.
A composted material derived from biogas production residues, spent mushroom substrate (SMS) and pig manure was evaluated as a partial or total replacement for peat in growth medium for tomato and ...pepper seedlings. Five different substrates were tested: T1, compost + perlite (5:1, v:v); T2, compost + peat + perlite (4:1:1, v:v:v); T3, compost + peat + perlite (2.5:2.5:1, v:v:v); T4, compost + peat + perlite (1:4:1, v:v:v); and CK, a commercial peat + perlite (5:1, v:v). The physical-chemical characteristics of the various media were analyzed, and the germination rate and morphological growth were also measured. Real-time Quantitative PCR (qPCR) was used to quantify Fusarium concentrations. The addition of compost to peat-based growth medium increased the pH, electrical conductivity, air porosity, bulk density, and nutrition (NPK), and decreased the water holding capacity and total porosity. The use of compost did not affect the percent germination at day 15 of the tomato and pepper seedlings. The addition of compost resulted in better or comparable seedling quality compared with CK and fertilized CK. The best growth parameters were seen in tomato and pepper seedlings grown in T1 and T2, with higher morphological growth in comparison with CK and fertilized CK. However, T2 showed the highest Fusarium concentration compared to compost and all growth media. Fusarium concentrations in T1, T3, and T4 did not differ significantly from those in CK for tomato seedlings, and those in T1 and T4 were also similar to those in CK for pepper seedlings. The results suggest that biogas residues and SMS compost is a good alternative to peat, allowing 100% replacement, and that 20–50% replacement produces tomato and pepper seedlings with higher morphological growth and lower Fusarium concentrations.
•Compost is a good media for the total or partial replacement of peat in seedlings.•The addition of compost resulted in better or comparable seedling quality compared with CK and fertilized CK.•The addition of compost did not increase the quantity of Fusarium except in pepper seedlings.
Tripterygium wilfordii Hook F. is a traditional medicinal plant known for its valuable secondary metabolites, including triptolide and celastrol, and can potentially be developed into ...pharmaceuticals. However, the production of these secondary metabolites in Tripterygium wilfordii is influenced by various environmental factors, making it essential to optimize fertilization techniques. This study aimed to measure the content of triptolide and celastrol in the above-ground and under-ground sections of Tripterygium wilfordii during three years of experiments in three types of growth media. Additionally, untargeted metabolomics analysis was conducted on Tripterygium wilfordii roots under five levels of nitrogen fertilizer rates. Excessive nitrogen fertilizer significantly increased the fresh shoot weight of Tripterygium willfordii and decreased the plant height and fresh root weight, whereas nitrogen fertilizer deficiency significantly decreased the fresh shoot and root weight, as well as the plant height. Additionally, both excessive and deficient nitrogen fertilizer levels limited the accumulation of triptolide and celastrol in Tripterygium wilfordii roots and shoots, with higher content observed at a moderate fertilizer level. This study also identified a total of 197 alkaloids, 216 flavonoids, 12 lignans, 25 coumarins, 227 phenolic acids, 13 tannins, 147 terpenoids, and 43 other secondary metabolites. Notably, alkaloids were up-regulated at a moderate nitrogen fertilizer level (30–60gN/pot), whereas flavonoids were down-regulated at a higher nitrogen level (90–120gN/pot). These findings emphasize the value of nitrogen fertilizer and controlled growth conditions in enhancing the production of secondary metabolites in Tripterygium wilfordii.
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•High levels of nitrogen fertilizer increased the shoot and root fresh weight.•High and low nitrogen fertilizer levels decreased triptolide and celastrol content.•Moderate nitrogen fertilizer levels showed the highest content of triptolide and celastrol.•More metabolites were up-regulated in moderate nitrogen fertilizer levels.
The individual role of biochar, compost and PGPR has been widely studied in increasing the productivity of plants by inducing resistance against phyto-pathogens. However, the knowledge on combined ...effect of biochar and PGPR on plant health and management of foliar pathogens is still at juvenile stage. The effect of green waste biochar (GWB) and wood biochar (WB), together with compost (Comp) and plant growth promoting rhizobacteria (PGPR; Bacillus subtilis) was examined on tomato (Solanum lycopersicum L.) physiology and Alternaria solani development both in vivo and in vitro. Tomato plants were raised in potting mixture modified with only compost (Comp) at application rate of 20% (v/v), and along with WB and GWB at application rate of 3 and 6% (v/v), each separately, in combination with or without B. subtilis. In comparison with WB amended soil substrate, percentage disease index was significantly reduced in GWB amended treatments (Comp + 6%GWB and Comp + 3%GWB; 48.21 and 35.6%, respectively). Whereas, in the presence of B. subtilis disease suppression was also maximum (up to 80%) in the substrate containing GWB. Tomato plant growth and physiological parameters were significantly higher in treatment containing GWB (6%) alone as well as in combination with PGPR. Alternaria solani mycelial growth inhibition was less than 50% in comp, WB and GWB amended growth media, whereas B. subtilis induced maximum inhibition (55.75%). Conclusively, the variable impact of WB, GWB and subsequently their concentrations in the soil substrate was evident on early blight development and plant physiology. To our knowledge, this is the first report implying biochar in synergism with PGPR to hinder the early blight development in tomatoes.
Agroecology as a transformative movement has gained momentum in many countries worldwide. In several cases, the implementation of agroecological practices has grown beyond isolated, local experiences ...to be employed by ever-greater numbers of families and communities over ever-larger territories and to engage more people in the processing, distribution, and consumption of agroecologically produced food. To understand the nonlinear, multidimensional processes that have enabled and impelled the bringing to scale of agroecology, we review and analyze emblematic cases that include the farmer-to-farmer movement in Central America; the national peasant agroecology movement in Cuba; the organic coffee boom in Chiapas, Mexico; the spread of Zero Budget Natural Farming in Karnataka, India; and the agroecological farmer-consumer marketing network "Rede Ecovida," in Brazil. On the basis of our analysis, we identify eight key drivers of the process of taking agroecology to scale: (1) recognition of a crisis that motivates the search for alternatives, (2) social organization, (3) constructivist learning processes, (4) effective agroecological practices, (5) mobilizing discourses, (6) external allies, (7) favorable markets, and (8) favorable policies. This initial analysis shows that organization and social fabric are the growth media on which agroecology advances, with the help of the other drivers. A more detailed understanding is needed on how these multiple dimensions interact with, reinforce, and generate positive feedback with each other to make agroecology's territorial expansion possible.
The principal objective of this paper was to assess the physical properties and weight or structural implications of some potential green roof growth media compositions practicable for use in the ...Nigerian built environment. The study carried out an essential selection of material constituents of growth media blends mixed in a 3:1:1 ratio of natural stone-based gravels, soil and compost respectively. Six substrate blends based on later-ite stones, ory and empirical field evaluation methods. The results revealed that the granite-based blend is the heaviest sample with 1,713.30 kg/m
in its saturated state, while the lightest in weight is the pumice blend with 869.30 kg/m
which is 50.7% less than the granite blend. The heaviest and the lightest outlined models were subsequently subjected to a weight analysis on a proposed reinforced concrete flat-roofed structure. The results showed that all the extensive green roof samples fall within the IBC stipulated range. The heaviest granite substrate obtained a design load of 0.951 kN/m
, while the lightest pumice blend recorded a design load of 0.576 kN/m
. Hence, it stands to offer an optimum alternative in green roof retrofitting projects for existing flat-roofed buildings. The study, therefore, submits that all samples evaluated involve readily available materials in the studied area and can be used with respect to their characteristic properties as presented in this study. It also serves as a reference point for all stakeholders in the research and building construction industry in Nigeria and beyond.
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