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Wheat is one of the most important crops to ensure food production globally. Understanding the mechanism of leaf senescence in wheat plays a crucial role in improving its productivity and resilience under various stress scenarios. In this study, we investigated biochemical, functional, and ultrastructural changes during leaf senescence in wheat genotypes with contrasting drought tolerance. For this, key parameters such as chlorophyll and total protein content, membrane stability, malondialdehyde level, and the activity of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, benzidine peroxidase, and catalase) were comparatively analyzed during both natural and drought-induced senescence. Additionally, the expression of superoxide dismutase isoform genes functioning in different cellular compartments was studied, alongside ultrastructural changes in flag leaves. The experiments involved genotypes of bread wheat (Triticum aestivum L.) and durum (Triticum durum Desf.) wheat. The plants were grown in controlled environment chambers under control and drought conditions using a completely randomized design. After the booting stage, irrigation was discontinued for drought-treated plants. Flag leaves were sampled at 7, 14, 21, 28, and 35 days after anthesis. Drought-tolerant genotypes exhibited slower chlorophyll degradation, lower lipid peroxidation, enhanced membrane stability, and stronger antioxidant responses, allowing them to maintain cellular function longer, whereas sensitive genotypes showed accelerated leaf senescence. Transcript levels of FeSOD increased significantly post-flowering but declined as senescence progressed, while MnSOD expression exhibited a rise towards the later stages of ontogenesis across all studied genotypes. Ultrastructural analysis revealed progressive damage to chloroplast membranes, thylakoid structures, and mesophyll cell walls under stress conditions, particularly in sensitive genotypes. These findings contribute to a deeper understanding of the physiological and molecular responses of wheat to drought stress, offering potential targets for improving crop performance in water-limited environments. [ABSTRACT FROM AUTHOR]

In this study, pure silver nanowires (Ag NWs) were initially synthesized using the polyol method. Subsequently, Ag–Ag2S NWs were synthesized through hybridization at two different concentrations (0.01 and 0.001 M). The final product, Ag–Ag2S–CdS NWs with a one-dimensional (1D) unit structure, was obtained via an ion-exchange method using a Cd2+ cation source. To characterize these NWs, various techniques were employed: X-ray Diffraction (XRD), Ultraviolet–Visible (UV–Vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Photoluminescence (PL) spectroscopy, and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDX) and, Transmission Electron Microscopy (TEM). The results confirmed the successful formation of the intended compounds through the synthesis process. TEM images verified the 1D core–shell structure of the NWs, with dimensions as follows: pure Ag NWs [D = 0.001 µm (1 nm)], Ag–Ag2S NWs (D = 0.52 µm), and Ag–Ag2S–CdS NWs (D = 0.61 µm). The PL spectrum revealed that pure Ag NWs exhibit high conductivity and surface plasmon resonance in the 400–500 nm range. The incorporation of semiconducting Ag2S altered the electron transition dynamics in the Ag–Ag2S system, attributed to surface defects in Ag2S. Additionally, in the presence of CdS, a decrease in intensity around 441 nm and spectrum broadening were observed, primarily due to Interband Damping. The degradation efficiency of Methylene Blue (MB) dye using Ag–Ag2S–CdS NWs as potential nanocatalysts was tested over various time intervals (60, 120, 180, 240, and 300 min) in three different environments (pH = 3, pH = 6, and pH = 10). The optimal degradation occurred in an acidic environment (pH = 3), achieving 97.9% efficiency at 300 min. The degradation kinetics were determined to be 0.0085 (60–120 min) and 0.0016 (120–300 min) in the acidic environment, 0.0029 in the neutral environment, and 0.0071 (60–180 min) and 0.001 (180–300 min) in the alkaline environment. [ABSTRACT FROM AUTHOR]

In the present investigation, pure and different concentrations (2%, 4%, 6%, 10%) of Ag-doped Co3O4 nanoparticles have been synthesized by the sonochemical method and subsequent calcination at different high temperatures. Structural, optical, morphological properties and elemental composition of synthesized nanoparticles have been characterized using X-ray diffraction, UV–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy. According to X-ray diffraction results, no peaks related to silver or silver oxide were observed in the diffractograms of doped samples. Blue shift was observed in the absorption curve of Ag-doped Co3O4 nanoparticles compared to undoped Co3O4 nanoparticles. From transmission electron microscopy measurements, 2%, 4% and 6% Ag-doped Co3O4 nanoparticles thermal annealed at 500 °C exhibit sphere-like and irregularly structured morphology, while 10% Ag-doped Co3O4 nanoparticles have a rhombohedral-like, hexagonal and spherical morphology. The dielectric constant value (ɛʹ) was found to decrease with increasing frequency and it can be explained by Maxwell–Wagner model. The value of the dielectric constant increased with increasing of temperature from 25 to 100 °C and the highest value was observed for Ag0.1Co2.9O4/PVA sample at 100 °C temperature. [ABSTRACT FROM AUTHOR]

The widespread exposure of metallic nanoparticles to the aquatic ecosystem and its adverse impact on human life is the colossal concern worldwide. In view of this, this context was investigated to analyze microscopically the bioaccumulation and localization of magnetite (Fe 3 O 4) nanoparticles in the cellular organelles of rainbow trout (Oncorhynchus mykiss , Walbaum, 1792) in aquatic conditions. Initially, Fe 3 O 4 nanoparticles were absorbed on to Elodea (Elodea canadensis) and fed to molluscs (Melanopsis praemorsa). Fish were fed with the same molluscs, and then the intestines and liver were examined using light and transmission electron microscopy. Results showed that nanoparticles were present in the cytoplasm and other organelles of cells (mitochondrion and lysosome) by absorbing through microvilli of the epithelial cells of the tunica mucosa in the intestine. Further, nanoparticles passed through the vessels of the lamina propria of the tunica mucosa and reached to the sinusoids of the liver via blood circulation. It was then accumulated from the endothelium of the sinusoid to the cytoplasm of liver hepatocytes and to mitochondria and lysosome. The accumulation of nanoparticles in the epithelial cells, cytoplasm, mitochondria, and lysosome revealed the degree of transparency of the pattern with slight hesitation. In summary, this investigation contributed towards the understanding of the physiological effects of Fe 3 O 4 nanoparticles on O. mykiss , which ascertains essentiality for sustainable development of nanobiotechnology in the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

A characteristic feature of C4 plants is the differentiation of the photosynthetic leaf tissues into two distinct cell types: mesophyll (M) and bundle sheath (BS) cells. We have investigated several biochemical parameters, including pigment composition, polypeptide patterns, fluorescence at 77K, the activity of photosystems and ultrastructure of mesophyll and bundle sheath chloroplasts of maize (Zea mays L.) plants. It is shown that the BS chloroplasts have ~2-fold higher chlorophyll a / b ratio than M chloroplasts, 6.15 and 3.12 respectively. The PSI apoprotein (68 kDa) was more abundant in BS than in M thylakoids. Polypeptides belonging to PSII core antenna, are in similar amounts in both types of membranes, but the 45kDa band is more intensive in M thylakoids. Polypeptides in the region of 28–24 kDa of the light-harvesting complex of PSII (LHCII) are also present in both types of chloroplasts, though their amounts are reduced in BS thylakoids. The chlorophyll fluorescence emission spectra in M cells showed the presence of three bands at 686, 695 and 735 nm characteristics of LHCII, PSII core and PSI complexes, respectively. However, in the fluorescence spectrum of agranal plastids, there are almost traces of the band at 695 nm, which belongs to the PSII core complex. The research results revealed that the photochemical activity of PSII in BS chloroplasts is ~5 times less than in the chloroplasts of M cells. The highest PSI activity was found in maize BS chloroplasts. The maize chloroplasts are an appropriate model to study the relationship between the structure and function of thylakoid membranes of C4 plants. We have examined biochemical, functional and structural characterisation of the granal and agranal chloroplasts of maize and these chloroplasts have been found to differ in their biochemical and structural organisation. The obtained results significantly contribute to the understanding of the relations between differential membrane structure and function in thylakoids of mesophyll and bundle sheath chloroplasts of maze plants. [ABSTRACT FROM AUTHOR]

A light and electron microscopic study of skin biopsies taken from 9 patients with ulcerative leishmaniasis of both sexes aged from 14 to 26 years in the territory of the Republic of Azerbaijan was carried out. Based on clinical, morphological and electron microscopic parameters, all patients were diagnosed with ulcerative cutaneous anthroponotic leishmaniasis (Leishmania (L.) tropica). Stained and unstained ultrathin (50-70 nm) sections were viewed and photographed using a JEM-1400 transmission electron microscope at an accelerating voltage of 80-120 kV. Analysis of data from light and electron microscopic studies at the ultrastructural level made it possible to describe the structure and identify the morphometric parameters of the amastigote form of the intracellular parasite. Besides, it was found that the distance between the plasmalemmas of the parasitophorous vacuoles and the parasite L. (L.) tropica is only 1 nm. This facilitates the passage of the necessary nutrients for the survival of this parasite. One of the important factors in the chronic course and relapse of leishmaniasis caused by L.(L.) tropica is the penetration of the amastigote stage into the cytoplasm along with macrophages, and also into fibroblasts with low phagocytic activity. Pathological changes (deformed nucleus, damage to plasmalemma, focal destruction of the cytoplasm structures, vacuolization, etc.) in the parasite L. (L.) tropica, localized in macrophages, were identified and described., Competing Interests: Declaration of competing interest We wish to confirm that there are no known conflicts of interest associated with this publication., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The widespread exposure of metallic nanoparticles to the aquatic ecosystem and its adverse impact on human life is the colossal concern worldwide. In view of this, this context was investigated to analyze microscopically the bioaccumulation and localization of magnetite (Fe 3 O 4 ) nanoparticles in the cellular organelles of rainbow trout ( Oncorhynchus mykiss , Walbaum, 1792) in aquatic conditions. Initially, Fe 3 O 4 nanoparticles were absorbed on to Elodea ( Elodea canadensis ) and fed to molluscs ( Melanopsis praemorsa ). Fish were fed with the same molluscs, and then the intestines and liver were examined using light and transmission electron microscopy. Results showed that nanoparticles were present in the cytoplasm and other organelles of cells (mitochondrion and lysosome) by absorbing through microvilli of the epithelial cells of the tunica mucosa in the intestine. Further, nanoparticles passed through the vessels of the lamina propria of the tunica mucosa and reached to the sinusoids of the liver via blood circulation. It was then accumulated from the endothelium of the sinusoid to the cytoplasm of liver hepatocytes and to mitochondria and lysosome. The accumulation of nanoparticles in the epithelial cells, cytoplasm, mitochondria, and lysosome revealed the degree of transparency of the pattern with slight hesitation. In summary, this investigation contributed towards the understanding of the physiological effects of Fe 3 O 4 nanoparticles on O. mykiss , which ascertains essentiality for sustainable development of nanobiotechnology in the aquatic ecosystem., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 The Author(s).)