Alterations In Cell Structure Research Articles

The Impact of Maternal Passive Tobacco Smoke on Neonatal Myocardiopathy in Mice.

Tobacco smoke has a global impact, particularly on pregnant women and their newborns. An emerging body of research suggests that passive tobacco smoking is a significant contributor to congenital cardiovascular disorders (CVDs). This study aimed to mimic the effects of passive tobacco smoke (PTS) on neonates exposed throughout the gestational period. Female mice (DPC = 0) were exposed to PTS; 24 cigarettes/day with an interval of 10 min between each cigarette in a specialized smoke chamber from conception to birth. Histopathological analysis was employed to evaluate PTS-induced cardiac damage in neonates. The results revealed significant alterations in cell structure, namely, widened interstitial spaces, hemorrhage, pyknotic nuclei, inflammatory cell infiltration, collagen deposition, and fibrosis. Maternal exposure to PTS during pregnancy may lead to neonatal myocardiopathy.

Effects of Cadmium Stress on Tartary Buckwheat Seedlings.

Cadmium (Cd) is a naturally occurring toxic heavy metal that adversely affects plant germination, growth, and development. While the effects of Cd have been described on many crop species including rice, maize, wheat and barley, few studies are available on cadmium's effect on Tartary buckwheat which is a traditional grain in China. We examined nine genotypes and found that 30 µM of Cd reduced the root length in seedlings by between 4 and 44% and decreased the total biomass by 7 to 31%, compared with Cd-free controls. We identified a significant genotypic variation in sensitivity to Cd stress. Cd treatment decreased the total root length and the emergence and growth of lateral roots, and these changes were significantly greater in the Cd-sensitive genotypes than in tolerant genotypes. Cd resulted in greater wilting and discoloration in sensitive genotypes than in tolerant genotypes and caused more damage to the structure of root and leaf cells. Cd accumulated in the roots and shoots, but the concentrations in the sensitive genotypes were significantly greater than in the more tolerant genotypes. Cd treatment affected nutrient uptake, and the changes in the sensitive genotypes were greater than those in the tolerant genotypes, which could maintain their concentrations closer to the control levels. The induction of SOD, POD, and CAT activities in the roots and shoots was significantly greater in the tolerant genotypes than in the sensitive genotypes. We demonstrated that Cd stress reduced root and shoot growth, decreased plant biomass, disrupted nutrient uptake, altered cell structure, and managed Cd-induced oxidative stress differently in the sensitive and tolerant genotypes of Tartary buckwheat.

Abstract PR007: Physical and metabolic aspects of therapy induced senescence and polyploidy in an evolving tumor microenvironment

Abstract Radiation and chemotherapy are highly effective at killing cancer cells but cells that survive treatment often develop therapy-induced senescence (TIS). Since growth is arrested in TIS, this has been considered a positive treatment outcome; however, senescent cells that remain metabolically active and develop a senescence associated secretory phenotype (SASP) can also promote cancer progression. In addition, a small number of cancer cells are able to escape this dormant state and contribute to cancer progression. Polyploid giant cancer cells (PGCCs) represent a small subpopulation of non-mitotic cancer cells that evades treatment through periods of transient dormancy and then relapses into full-blown disease through amitotic budding into chemoresistant progenitor cells. The PGCC phenotype mimics senescent cells in multiple ways, including enlarged size, increased beta-galactosidase expression, increased metabolic activity, and pro-inflammatory SASP; yet, there is a significant gap in our understanding of how PGCCs contribute to TIS escape and subsequent chemoresistance. In addition, increased numbers of large PGCCs are seen in late stage and metastatic cancers; yet, their role in tumor recurrence and metastasis has not been established. We previously showed PGCCs have a unique actin cytoskeletal organization, giving rise to elevated stiffness and migratory persistence. These findings prompted us to further examine vimentin intermediate filaments (VIFs) that act as shock absorbers in the cell, protecting cells from compressive loads. Based on this, we postulated that PGCCs have unique adaptations in their vimentin structure to help support their enlarged morphology and drive their persistent migration. Indeed, we showed that PGCCs have increased levels of cytoplasmic vimentin and evenly distributed VIFs compared to non-PGCCs. This dispersed network of VIFs often polarized at the leading-edge during migration, and was necessary for PGCCs phenotype, as disruption of VIFs decreased PGCC volume and blocked migratory persistence. The VIF network also scaffolds lysosomes and autophagosomes in the cytosol to regulate their fusion during autophagy. Our new data clearly shows that inhibiting autophagy with Bafilomycin limits PGCC migration. In addition, targeting VIF structure also blocks autophagy. Thus, the structure of VIFs and autophagic flux are both critical in directing PGCCs migratory persistence. We have developed a novel 3D tumor microenvironment model that allows us to monitor cancer cell behavior over 4-6 weeks, which allows us to monitor cell recovery from TIS and dormancy. Using this model, we show that PGCC’s unique biophysical properties are directly linked to their dysregulated metabolism and altered cell structure. These studies provide critical information about how aging, TIS, and polyploidy affect evolving tumor microenvironments. Citation Format: Michelle R. Dawson, Deepraj Ghosh. Physical and metabolic aspects of therapy induced senescence and polyploidy in an evolving tumor microenvironment [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr PR007.

The Use of Non-targeted Lipidomics and Histopathology to Characterize the Neurotoxicity of Bifenthrin to Juvenile Rainbow Trout (Oncorhynchus mykiss).

Due to the detection frequencies and measured concentrations in surface water, the type I pyrethroid insecticide, bifenthrin, has been of particular concern within the Sacramento-San Joaquin Delta in California. Concentrations have been detected above levels previously reported to impair neuroendocrine function and induce neurotoxicity to several species of salmonids. Metabolomic and transcriptomic studies indicated impairment of cellular signaling within the brain of exposed animals and potential alteration of lipid metabolism. To better understand the potential impacts of bifenthrin on brain lipids, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to mean bifenthrin concentrations of 28 or 48 ng/L for 14 days, and non-targeted lipidomic profiling in the brain was conducted. Brain tissue sections were also assessed for histopathological insult following bifenthrin treatment. Bifenthrin-exposed trout had a concentration-dependent decrease in the relative abundance of triglycerides (TGs) with levels of phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) significantly altered following 48 ng/L bifenthrin exposure. An increased incidence of histopathological lesions, such as focal hemorrhages and congestion of blood vessels, was noted in the brains of bifenthrin-treated animals, suggesting an association between altered lipid metabolism and neuronal cell structure and integrity.

Fumonisin B1 Induces Immunotoxicity and Apoptosis of Chicken Splenic Lymphocytes

Fumonisin B1 (FB1), produced by Fusarium, is among the most abundant and toxic mycotoxin contaminations in feed, causing damages to the health of livestock. However, the mechanisms of FB1 toxicity in chickens are less understood. As splenic lymphocytes play important roles in the immune system, the aim of this study was to investigate the immunotoxic effects and mechanisms of FB1 on chicken splenic lymphocytes. In the present study, the chicken primary splenic lymphocytes were harvested and treated with 0, 2.5, 5, 10, 20 and 40 μg/mL FB1. Then, the cell proliferation, damage, ultrastructure, inflammation and apoptosis were evaluated. Results showed that the proliferation rate of splenic lymphocytes was decreased by FB1 treatments. The activity of lactate dehydrogenase (LDH) was increased by FB1 treatments in a dose-dependent manner, implying the induction of cell damage. Consistently, the ultrastructure of splenic lymphocytes showed that FB1 at all the tested concentrations caused cell structure alterations, including nuclear vacuolation, mitochondrial swelling and mitochondrial crest fracture. Besides, immunosuppressive effects of FB1 were observed by the decreased concentrations of interleukin-2 (IL-2), IL-4, IL-12 and interferon-γ (IFN-γ) in the cell culture supernatant. Furthermore, apoptosis was observed in FB1-treated cells by flow cytometry. The mRNA expressions of apoptosis-related genes showed that the expression of Bcl-2 was decreased, while the expressions of the P53, Bax, Bak-1, and Caspase-3 were increased with FB1 treatment. Similar results were found in the concentrations of apoptosis-related proteins in the cell supernatant by ELISA assay. Moreover, regression analysis indicated that increasing FB1 concentration increased LDH activity, concentrations of Bax, Bak-1 and mRNA expression of Bak-1 linearly, increased M1 area percentage quadratically, decreased concentration of IFN-γ, mRNA expression of Bcl-2 linearly, and decreased concentrations of IL-2 and IL-4 quadratically. Besides, regression analysis also showed reciprocal relationships between IL-12 concentration, Caspase-3 mRNA expression and increasing FB1 concentration. The increasing FB1 concentration could decrease IL-12 concentration and increase Caspase-3 mRNA expression. Altogether, this study reported that FB1 induced the immunotoxicity of chicken splenic lymphocytes and caused splenic lymphocytes apoptosis by the Bcl-2 family-mediated mitochondrial pathway of caspase activation.

Mechanical suppression of breast cancer cell invasion and paracrine signaling to osteoclasts requires nucleo-cytoskeletal connectivity

Exercise benefits the musculoskeletal system and reduces the effects of cancer. The effects of exercise are multifactorial, where metabolic changes and tissue adaptation influence outcomes. Mechanical signals, a principal component of exercise, are anabolic to the musculoskeletal system and restrict cancer progression. We examined the mechanisms through which cancer cells sense and respond to low-magnitude mechanical signals introduced in the form of vibration. Low-magnitude, high-frequency vibration was applied to human breast cancer cells in the form of low-intensity vibration (LIV). LIV decreased matrix invasion and impaired secretion of osteolytic factors PTHLH, IL-11, and RANKL. Furthermore, paracrine signals from mechanically stimulated cancer cells, reduced osteoclast differentiation and resorptive capacity. Disconnecting the nucleus by knockdown of SUN1 and SUN2 impaired LIV-mediated suppression of invasion and osteolytic factor secretion. LIV increased cell stiffness; an effect dependent on the LINC complex. These data show that mechanical vibration reduces the metastatic potential of human breast cancer cells, where the nucleus serves as a mechanosensory apparatus to alter cell structure and intercellular signaling.

Quantitative intravital Ca2+ imaging maps single cell behavior to kidney tubular structure.

Ca2+ is an important second messenger that translates extracellular stimuli into intracellular responses. Although there has been significant progress in understanding Ca2+ dynamics in organs such as the brain, the nature of Ca2+ signals in the kidney is still poorly understood. Here, we show that by using a genetically expressed highly sensitive reporter (GCaMP6s), it is possible to perform imaging of Ca2+ signals at high resolution in the mouse kidney in vivo. Moreover, by applying machine learning-based automated analysis using a Ca2+-independent signal, quantitative data can be extracted in an unbiased manner. By projecting the resulting data onto the structure of the kidney, we show that different tubular segments display highly distinct spatiotemporal patterns of Ca2+ signals. Furthermore, we provide evidence that Ca2+ activity in the proximal tubule decreases with increasing distance from the glomerulus. Finally, we demonstrate that substantial changes in intracellular Ca2+ can be detected in proximal tubules in a cisplatin model of acute kidney injury, which can be linked to alterations in cell structure and transport function. In summary, we describe a powerful new tool to investigate how single cell behavior is integrated with whole organ structure and function and how it is altered in disease states relevant to humans.

Relationships Between Cell Structure Alterations and Berry Abscission in Table Grapes.

The aim of this study was to explore the relationships between structure alterations and postharvest berry abscission in “Muscat Kyoho” “Kyoho” and “Nanyu” table grapes stored for 0, 3, or 6 days at room temperature. Microstructure analysis showed that a large number of the stalk-berry junction cells of “Muscat Kyoho” and “Kyoho” were lignified and suberized at 0 day, whereas these events seldom occurred in “Nanyu.”Furthermore, the berry brush cells of the three varieties, especially those of “Nanyu,” were small and dense. At 3 days, the numbers of lignified and suberized cells of “Muscat Kyoho” and “Kyoho” were reduced, and the cells had degraded, ruptured, and disappeared by 6 days. The berry brush cells of “Muscat Kyoho” and “Kyoho” were larger and more loosely arranged than were those of “Nanyu.” Ultrastructure analysis showed that the cells increased in size from small to large and became loosely arranged; the smallest changes were observed in “Nanyu.” The cells of “Muscat Kyoho” and “Kyoho” were hydrolyzed, liquated, and covered by granular substances at 6 days, and these features were especially prominent in “Muscat Kyoho.” The detachment force of grapes declined steadily (p < 0.05) and was accompanied by an increase in berry abscission. “Nanyu” maintained the highest detachment force and the lowest berry abscission during storage (p < 0.05), followed by “Kyoho” and “Muscat Kyoho.” Structural alterations were directly related to berry abscission and correlated inversely with detachment force, with the greatest alterations occurring in “Muscat Kyoho,” followed by “Kyoho” and then “Nanyu.”

Rapid in Vitro Assessment of Clostridioides difficile Inhibition by Probiotics Using Dielectrophoresis to Quantify Cell Structure Alterations.

Clostridioides difficile (C. difficile) infection (CDI) is the primary cause of nosocomial antibiotic-associated diarrhea, with high recurrence rates following initial antibiotic treatment regimens. Restoration of the host gut microbiome through probiotic therapy is under investigation to reduce recurrence. Current in vitro methods to assess C. difficile deactivation by probiotic microorganisms are based on C. difficile growth inhibition, but the cumbersome and time-consuming nature of the assay limits the number of assessed permutations. Phenotypic alterations to the C. difficile cellular structure upon interaction with probiotics can potentially enable rapid assessment of the inhibition without the need for extended culture. Because supernatants from cultures of commensal microbiota reflect the complex metabolite milieu that deactivates C. difficile, we explore coculture of C. difficile with an optimal dose of supernatants from probiotic culture to speed growth inhibition assays and enable correlation with alterations to its prolate ellipsoidal structure. Based on sensitivity of electrical polarizability to C. difficile cell shape and subcellular structure, we show that the inhibitory effect of Lactobacillus spp. supernatants on C. difficile can be determined based on the positive dielectrophoresis level within just 1 h of culture using a highly toxigenic strain and a clinical isolate, whereas optical and growth inhibition measurements require far greater culture time. We envision application of this in vitro coculture model, in conjunction with dielectrophoresis, to rapidly screen for potential probiotic combinations for the treatment of recurrent CDI.

The preventive effect of Rome beauty (Malus sylvestris Mill) apple peel’s extract towards the malondialdehyde (MDA) levels of rat (Rattus norvegicus) stomach exposed to plumbum acetate

Plumbum (Pb) is one of heavy metals that can turn into free radicals, resulting in the descent and alteration of cell structures of the stomach. Apple of Rome beauty contains high flavonoids which act as antioxidant agents by supplying hydrogen ions to the free radicals. This research utilized white rat (Rattus norvegicus) divided into 5 treatment groups, each group consisted of 4 white rats. They are negative control, positive control which were given 10 mg of Pb acetate for each rat/day in 14 days, and preventive control group which were given the extract of Rome Beauty apple peel within the dosage of 28 mg/200 g, 56 mg/200 g, and 112 mg/200 g for 21 days. The parameter observed were MDA levels of stomach. The result was then analysed with One Way ANOVA which was followed by Turkey. The result of this research exhibited the preventive group which was given Rome Beauty apple peel within the dosage of 112 mg/200 g was able to halt the increase of MDA levels significantly (p<0.05), which was 82.16 ± 1.40 μg/ml. The research concluded that Rome Beauty apple peel contain antioxidant that can prevent the damage of stomach tissue resulted by Pb acetate.

Response surface methodology can be used to predict photoinactivation of foodborne pathogens using Rose Bengal excited by 530 nm LED

AbstractIn this work, the photodynamic bactericidal effect of Rose Bengal (RB), combined with green LED light, against Staphylococcus aureus and Salmonella Typhimurium, was investigated. The interaction of RB concentration and illumination time was evaluated using a response surface methodology, and a second‐order polynomial empirical model was adjusted to the experimental data. The derived model predicted the combined influences of these factors on S. aureus and S. Typhimurium counts, in accordance with predictions and experimental observations (R2 = 0.8483 and p = .0013 for S. aureus; R2 = 0.9191 and p = .0001 for S. Typhimurium). Total inhibition of S. aureus and S. Typhimurium was observed when applying a light dose of 0.125 J cm−2 and 152.0 J cm−2, respectively. The treatments also showed loss of membrane integrity, morphological changes, and internal cell structural alterations. In sum, the polynomial model developed could provide accurate information on the combined influences of RB and green LED light in aPDT treatment and, that this combination was able to inactivate S. aureus and S. Typhimurium.

Antimicrobial and antibiofilm activities of paeoniflorin against carbapenem-resistant Klebsiella pneumoniae.

To evaluate the antimicrobial effect of paeoniflorin against carbapenem-resistant Klebsiella pneumoniae (CRKP). Minimum inhibitory concentration (MIC) of paeoniflorin against CRKP was determined by agar dilution method. Changes in intracellular ATP concentration, intracellular pH (pHin), cell membrane potential and membrane integrity were investigated to assess the influence of paeoniflorin on cell membrane damage. Additionally, alterations in cell structure of CRKP cells and cell damage within biofilms were examined. The results indicated that paeoniflorin was effective against CRKP at MIC of 1·2mgml-1 . Paeoniflorin destroyed the integrity of CRKP cell membrane, as was confirmed by decrease of intracellular ATP, pHin, membrane potential, as well as distinctive alteration in cell morphology, resulting in leakage of CRKP intracellular components. Moreover, paeoniflorin displayed a markedly inhibitory influence on biofilm formation of CRKP and inactivated CRKP cells within biofilms. Paeoniflorin shows promise as an effective antibiotic against CRKP with the potential to be an alternative therapeutic agent. This study provides information about the potential use of paeoniflorin to reduce the infection of CRKP in clinical practice and food production.

Ethylene and 1-MCP treatments affect leaf abscission and associated metabolism of Chinese cabbage

Leaf abscission during storage of Chinese cabbage (Brassica rapa, subspecies pekinensis and chinensis) can result in serious losses. To uncover the effects of the plant hormone ethylene on leaf abscission, harvested cabbages were treated with ethylene and its competitive inhibitor, 1-methylcyclopropene (1-MCP), and with 1-MCP followed by ethylene. Ethylene treatment accelerated leaf abscission, altered cell structure of the abscission zones, and increased activity and gene expression of cell wall-degrading enzymes. Expression of genes related to ethylene receptors and signaling pathways including BcERS1, BcERS2, BcETR2, BcCTR1, BcEIL1, BcEIL2, and BcEIL3 were also up-regulated. In 1-MCP-treated samples, leaf breakstrength was higher, and the increase of cell wall-degrading enzyme activity and the expression of enzyme-related genes were reduced. Notably, ethylene sensitivity recovered upon subsequent ethylene treatment following 1-MCP treatment. These results indicated that ethylene may constitute an important factor in leaf abscission of Chinese cabbage.

Nonthermal pretreatments enhances drying kinetics and quality properties of dried ginger (Zingiber officinale Roscoe) slices

AbstractThe objective of this present work was to investigate the effect of ultrasound (US), osmotic dehydration (OD), and osmosonication (OS) pretreatment on microstructure, weight loss, texture, mass transfer, chromatic properties and drying kinetics of ginger slices under relative humidity convective drying. The results revealed that OS pretreatment yielded higher weight loss (16.5%) and lower firmness (12.11 N) than US (9.8%, 20.33 N) and OD (6.5%, 15.30 N). Microstructure analysis showed that OS, US, and OD pretreatments altered cell structure and resulted in the observable formation of several microchannels and collapsed the cell structure. Mass transfer data showed that the OS pretreated sample led to higher solid gain (3.2%) and water loss (5.1%) than the US (2.36%, 4.2%) and OD (1.7%, 2.53%) pretreatments. The chromatic property analysis revealed that the chroma value and hue angle was higher for OS treated sample (29.74, 88.77°) compared the US (26.95, 85.76°) and OD (22.96, 82.24°) treated sample. Among the three pretreatments, OS was found to enhance the drying kinetics comparative to the US and OD pretreated sample. Weibull model fitted well to the experimental results (R2 &gt; .99) than the first order.Practical applicationsUltrasound, osmotic dehydration, and osmosonication are unique pretreatment techniques that are widely used prior to drying of various agricultural products due to its numerous advantages over conventional methods. Its application in the drying of foods could help shorten the drying time, reduce processing costs, improve energy consumption and efficiency and preserve the physical and nutritional properties of the dried product. The outcomes of the present study will provide a better understanding of different nonthermal pretreatment methods and also make available more information for selecting pretreatment techniques for ginger drying.

Lysophosphatidic Acid Signaling in Diabetic Nephropathy.

Lysophosphatidic acid (LPA) is a bioactive phospholipid present in most tissues and body fluids. LPA acts through specific LPA receptors (LPAR1 to LPAR6) coupled with G protein. LPA binds to receptors and activates multiple cellular signaling pathways, subsequently exerting various biological functions, such as cell proliferation, migration, and apoptosis. LPA also induces cell damage through complex overlapping pathways, including the generation of reactive oxygen species, inflammatory cytokines, and fibrosis. Several reports indicate that the LPA–LPAR axis plays an important role in various diseases, including kidney disease, lung fibrosis, and cancer. Diabetic nephropathy (DN) is one of the most common diabetic complications and the main risk factor for chronic kidney diseases, which mostly progress to end-stage renal disease. There is also growing evidence indicating that the LPA–LPAR axis also plays an important role in inducing pathological alterations of cell structure and function in the kidneys. In this review, we will discuss key mediators or signaling pathways activated by LPA and summarize recent research findings associated with DN.

Bladder cancer extracellular vesicles drive tumorigenesis by inducing the unfolded protein response in endoplasmic reticulum of nonmalignant cells

The field cancerization effect has been proposed to explain bladder cancer's multifocal and recurrent nature, yet the mechanisms of this effect remain unknown. In this work, using cell biology, flow cytometry, and qPCR analyses, along with a xenograft mouse tumor model, we show that chronic exposure to tumor-derived extracellular vesicles (TEVs) results in the neoplastic transformation of nonmalignant human SV-HUC urothelial cells. Inhibition of EV uptake prevented this transformation. Transformed cells not only possessed several oncogenic properties, such as increased genome instability, loss of cell-cell contact inhibition, and invasiveness, but also displayed altered morphology and cell structures, such as an enlarged cytoplasm with disrupted endoplasmic reticulum (ER) alignment and the accumulation of smaller mitochondria. Exposure of SV-HUC cells to TEVs provoked the unfolded protein response in the endoplasmic reticulum (UPRER). Prolonged induction of UPRER signaling activated the survival branch of the UPRER pathway, in which cells had elevated expression of inositol-requiring enzyme 1 (IRE1), NF-κB, and the inflammatory cytokine leptin, and incurred loss of the pro-apoptotic protein C/EBP homologous protein (CHOP). More importantly, inhibition of ER stress by docosahexaenoic acid prevented TEV-induced transformation. We propose that TEVs promote malignant transformation of predisposed cells by inhibiting pro-apoptotic signals and activating tumor-promoting ER stress-induced unfolded protein response and inflammation. This study provides detailed insight into the mechanisms underlying the bladder cancer field effect and tumor recurrence.

Rice SDSFL1 plays a critical role in the regulation of plant structure through the control of different phytohormones and altered cell structure

Semi-dwarfism is one of the most important agronomic traits for many cereal crops. In the present study, a mutant with semi-dwarf and short flag leaf 1, sdsfl1, was identified and characterized. The sdsfl1 mutant demonstrated some distinguished structural alterations, including shorter plant height and flag leaf length, increased tiller numbers and flag leaf width, and decreased panicle length compared with those of wild type (WT). Genetic analysis suggested that the mutant traits were completely controlled by a single recessive gene. The SDSFL1 gene was mapped to the long arm of chromosome 3 within a region of 44.6 kb between InDel markers A3P8.3 and A3P8.4. The DNA sequence analysis revealed that there was only a T to C substitution in the coding region of LOC_Os03g63970, resulting in the substitution of Tryptophan (Try) to Arginine (Arg) and encoding a GA 20 oxidase 1 protein of 372 amino acid residues. Photosynthesis analysis showed that the photosynthetic rate (Pn), stomatal conductance (Gs), and intercellular CO2 concentration (Ci) were significantly increased in sdsfl1. Chlorophyll a (Chl a), total Chl, and carotenoid contents were significantly increased in sdsfl1 compared with those in WT. sdsfl1 carried a reduced level of GA3 but reacted to exogenously applied gibberellins (GA). Moreover, the levels of abscisic acid (ABA), indole 3-acetic acid (IAA), and salicylic acid (SA) were notably improved in sdsfl1, whereas there was no noteworthy change in jasmonic acid (JA). The results thus offer a visible foundation for the molecular and physiological analysis of the SDSFL1 gene, which might participate in various functional pathways for controlling plant height and leaf length in rice breeding.

Melatonin alleviates low-sulfur stress by promoting sulfur homeostasis in tomato plants

Despite involvement of melatonin (MT) in plant growth and stress tolerance, its role in sulfur (S) acquisition and assimilation remains unclear. Here we report that low-S conditions cause serious growth inhibition by reducing chlorophyll content, photosynthesis and biomass accumulation. S deficiency evoked oxidative stress leading to the cell structural alterations and DNA damage. In contrast, MT supplementation to the S-deprived plants resulted in a significant diminution in reactive oxygen species (ROS) accumulation, thereby mitigating S deficiency-induced damages to cellular macromolecules and ultrastructures. Moreover, MT promoted S uptake and assimilation by regulating the expression of genes encoding enzymes involved in S transport and metabolism. MT also protected cells from ROS-induced damage by regulating 2-cysteine peroxiredoxin and biosynthesis of S-compounds. These results provide strong evidence that MT can enhance plant tolerance to low-S-induced stress by improving S uptake, metabolism and redox homeostasis, and thus advocating beneficial effects of MT on increasing the sulfur utilization efficiency.

Cyclic tensile properties of the polylactide nanocomposite foams containing cellulose nanocrystals

Cellulose nanocrystal (CNC) filled polylactide (PLA) nanocomposites are of interest because both the filler particles and matrix polymer are biodegradable. Foaming with high pressure inert gas is a promising way to open potential applications of this kind of green nanocomposites as lightweight materials. To establish the structure–property relations of this kind of foams is hence of great significance. In this work, PLA/CNC nanocomposites containing three types of CNC particles, including pristine CNC and acetylated ones with lower and moderate degrees of substitution, were foamed using CO2 as the blowing agent for the studies mentioned above. The results show that the presence of all three kinds of CNC particles has large influence on cellular structure and cell morphology, and as a result, affects final mechanical properties of foams. The tensile cycle tests were then performed as an efficient tool to further figure out clear information on the contributions of reinforcement of filler and altered cell structure to the plasticity and elasticity of foams. The obtained results provide useful information on the optimization of cell structure and mechanical properties of PLA foams using small amounts of CNC particles through controlling their surface properties.

Drying Damage on Physiological Properties of Rice Seed Associated with Ultrastructure Changes

Abstract The aim of the present study was to investigate the alterations of the physiological properties associated with the ultrastructure changes of rice seed after drying at different temperatures. The drying process was accomplished at 30, 45, 60, 75 and 90°C and at 29.3%, 13.0%, 6.4%, 3.2%, and 1.8% relative humidity, respectively. As a result, the germination percentage of the rice seeds was reduced as the increasing of the drying temperature and the highest value of vigor index was recorded at 45°C due to the dormancy breakage. There were no changes in the color of the raw rice seed dried at different temperatures; however, the yellowness of the brown rice and the electrical conductivity increased with the increasing drying temperature. The starch granules of the rice endosperm dried at 45°C were wrinkled and wilted and this damage occurred with high intensity after drying at temperatures above 60°C. The structure of the starch granules eventually became rupture when the drying temperature reached to 90°C. The cells of the rice embryo presented a contraction of their volumes drying at temperatures above 45°C due to the degradation of the middle lamella. The form of the oil drops was also altered after drying. At temperature above 75°C, the drops broke up and coalesced. It was concluded that the physiological quality of rice seed was closely associated with the alterations of cell structure during drying process.