Cell wall biosynthesis impairment affects the budding lifespan of the Saccharomyces cerevisiae yeast

The Saccharomyces cerevisiae yeast is one of the most widely used model in studies of cellular and organismal biology, including as aging and proliferation. Although several constraints of aging and budding lifespan have been identified, these processes have not yet been fully understood. Previous studies of aging in yeast have focused mostly on the molecular basics of the underlying mechanisms, while physical aspects, particularly those related to the cell wall, were rather neglected. In this paper, we examine for the first time, to our knowledge, the impact of cell wall biosynthesis disturbances on the lifespan in the budding yeast. We have used a set of cell wall mutants, including knr4\Delta, cts1\Delta, chs3\Delta, fks1\Delta and mnn9\Delta, which affect biosynthesis of all major cell wall compounds. Our results indicated that impairment of chitin biosynthesis and cell wall protein mannosylation reduced the budding lifespan, while disruption in the 1,3-\beta-glucan synthase activity had no adverse effect on that parameter. The impact varied in the severity and the most notable effect was observed for the mnn9\Delta mutant. What was interesting, in the case of the dysfunction of the Knr4 protein playing the role of the transcriptional regulator of cell wall chitin and glucan synthesis, the lifespan increased significantly. We also report the phenotypic characteristics of cell wall-associated mutants as revealed by imaging of the cell wall using transmission electron microscopy, scanning electron microscopy and atomic force microscopy. In addition, our findings support the conviction that achievement of the state of hypertrophy may not be the only factor that determines the budding lifespan

La biosynthèse de la cellulose (contribution de différentes isoformes d AtCESA et biomécanique de mutants cellulose-déficients chez le seigle et Arabidopsis)

La famille des celluloses synthases (CESA) chez Arabidopsis comprend 10 membres. Les complexes responsables de la production de cellulose dans la paroi primaire contiennent au moins trois isoformes différentes: CESA1, -3 et -6. Les mutants correspondants sont nains et cellulose-déficients. Nous avons étudié la composition et la régulation de ces complexes CESA par des approches biochimiques (Juraniec et al., PNAS 2007). Nous avons montré, à l aide de doubles et triples combinaisons avec cesa6prc1-1, que les isoformes CESA2 et -5, proches de CESA6 en terme de séquence, sont partiellement redondantes avec CESA6. Le phénotype nain de cesa6prc1-1 à l obscurité est réverté à la lumière. Le gène CESA5, qui ne s exprime qu à la lumière, quand il était placé sous le contrôle du promoteur CESA6 était capable de complémenter le phénotype de cesa6prc1-1 à l obscurité ce qui montre que la fonction de CESA5 est comparable à celle de CESA6. De plus, nous avons montré que CESA2 et -5 sont cibles de l isoxabène et la compétition avec CESA6 au sein des complexes explique la résistance inférieure à l isoxabène de cesa6ixr2-1 par rapport à cesa3ixr1-2. L étude biomécanique a été consacrée aux mutants CESA d Arabidopsis mais aussi à des lignées cassantes de seigle. Bien que les gènes ne soient pas identifiés, le phénotype cassant chez le seigle résulte de perturbations dans la biosynthèse et/ou le dépôt de la cellulose. Les corrélations établies entre la teneur en cellulose et les paramètres mécaniques permettent de conclure que la quantité mais aussi des modifications ultrastructurales de cellulose sont responsables de la diminution de la résistance mécanique des plantes cassantes.The cellulose synthase (CESA) family in Arabidopsis comprises 10 members. It is commonly admitted that primary cell wall cellulose synthesis complexes contain three distinct isoforms: CESA1, -3 and -6. Corresponding mutants are cellulose-deficient and present growth defects. We used biochemical approaches to study the composition and regulation of these complexes (Juraniec et al., PNAS 2007). CESA2 and -5, closely related to CESA6, were also shown to be involved in cell elongation. cesa2 and -5 mutants did not demonstrate a clear phenotype but their double and triple combinations with cesa6prc1-1 showed that CESA2 and -5 are partially redundant with CESA6. Interestingly, the growth defect in cesa6prc1-1 is reverted by light. CESA5, normally expressed only in the light, driven by CESA6 promoter complemented the dark-grown phenotype of cesa6prc1-1 indicating that CESA5 overlaps CESA6 in function. We have shown that CESA2 and -5 are both targets of the herbicide isoxaben. It implies that lower isoxaben resistance of cesa6ixr2-1 versus cesa3ixr1-2 is due to the competition between CESA2, -5 and -6. The biomechanical part was devoted to the analysis of CESA mutants in Arabidopsis and also to brittle culm strains of rye (Secale cereale). Although the affected genes in rye have not been identified yet, several lines of evidence indicate that the brittle phenotype results from an aberrant cellulose synthesis and/or deposition. Correlations between cellulose content and mechanical parameters allowed us to conclude that cellulose content but also ultrastructural modifications in microfibrilar fraction are responsible for dramatically decreased mechanical strength in brittle plants.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Gold Nanoparticles Promote Oxidant-Mediated Activation of NF-κB and 53BP1 Recruitment-Based Adaptive Response in Human Astrocytes

Nanogold-based materials are promising candidate tools for nanobased medicine. Nevertheless, no conclusive information on their cytotoxicity is available. In the present study, we investigated the effects of gold nanoparticles (AuNPs) on human astrocytes in vitro. Nanogold treatment in a wide range of concentrations did not result in cytotoxicity. In contrast, nanogold provoked changes in the astrocyte cell cycle and induced senescence-associated β-galactosidase activity. AuNPs promoted oxidative stress and caused activation of NF-κB pathway. After nanogold treatment, an inverse correlation between the formation of 53BP1 foci and micronuclei generation was observed. The robust 53BP1 recruitment resulted in reduced micronuclei production. Thus, nanogold treatment stimulated an adaptive response in a human astrocyte cell

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Abstract The paper describes experimental studies of Plasma-Focus (PF) discharges carried out within the modernized PF-360 facility, which was operated with an additional D 2 -gas puffing into the region of the collapsing current sheath and PF pinch formation, i.e. into space in front of the electrode outlet. The main aim of these studies was to increase a neutron yield from PF discharges by using fast deuteron beams, which are usually emitted from a pinch column and which can interact with additional D 2 -gas target

Green dialysis – let us talk about dialysis fluid.

Background: Hemodialysis is one of the most resources consuming medical intervention. Due to its concept, the proper amount of dialysis fluid passed through dialyser is crucial to obtain the expected outcomes. The most frequent source of dialysis fluid is production from liquid concentrate (delivered in containers or plastic bags) in dialysis machine. Alternatively, concentrates for dialysis may be produced in dialysis center by dilution in mixing devices dry or semi-dry pre-mixed compounds connected with system of central dialysis fluid delivery system. Dialysate consumption depends on various factors like type of hemodialysis machine,session duration,prescribed flow etc. Summary: Modern hemodialysis machines are equipped with the modules which automatically reduce flow rate of dialysis fluid to the patient blood flow and minimize dialysate consumption during preparation and after reinfusion. Smart using of available options offered by manufacturers allows to save additional portion of acid concentrate and water. The weight of concentrates to be deliver to the dialysis center is the major factor influencing on the cost (financial and environmental) of transportation from the manufacturer to the final consumer. The crisis on the energy carriers market and extremely high fuel prices made the transportation cost the one of the significant cost of the treatment,which must be bear by supplier and finally influence on the price of goods. Key messages: The careful choice of the concentrate delivery system can improve cost-effectiveness of dialysis. Such solutions implemented in dialysis unit helps to make significant savings and decrease the impact on natural environment by carbon footprint reduction

Fatty Acid Profile and Biological Activities of Linseed and Rapeseed Oils

It has been postulated that fatty acids found in edible oils may exert beneficial health effects by the modulation of signaling pathways regulating cell differentiation and proliferation, especially in the treatment of cardiovascular diseases. In the present study, the biological effects of selected edible oils—linseed (LO) and rapeseed (RO) oils—were tested in vitro on fibroblast cells. The fatty acid profile of the oils was determined using gas chromatography and FTIR spectroscopy. LO was found to be rich in α-linolenic acid (ALA), whereas oleic acid was the most abundant species in RO. Fatty acids were taken up by the cells and promoted cell proliferation. No oxidative stress-mediated cytotoxic or genotoxic effects were observed after oil stimulation. Oils ameliorated the process of wound healing as judged by improved migration of fibroblasts to the wounding area. As ALA-rich LO exhibited the most potent wound healing activity, ALA may be considered a candidate for promoting the observed effect

Cytotoxic and cytostatic side effects of chitosan nanoparticles as a non-viral gene carrier

Although chitosan nanoparticles (CNs) became a promising tool for several biological and medical applications owing to their inherent biocompatibility and biodegradability features, studies regarding their effects on cytotoxic and cytostatic properties still remain insufficient. Therefore, in the present study, we decided to perform comprehensive analysis of the interactions between CNs–pKindling-Red-Mito (pDNA) and different cell line models derived from blood system and human solid tissues cancers. The resulting CNs-pDNA was investigated in terms of their cellular uptake, transfection efficiency, and physico-chemical, cytotoxic and cytostatic properties. The nanoparticles showed high encapsulation efficiency and physical stability for various formulations even after two days time period. Moreover, high gene expression levels were observed after 96 h of transfection. CNs-pDNA treatment, despite the absence of oxidative stress induction, caused cell cycle arrest in G0/G1 phase and as a consequence led to premature senescence which turned out to be both p21-dependent and p21-independent. Also, observed DNMT2 upregulation may suggest the activation of different pathways protecting from the results of CNs-mediated stress. In conclusion, treatment of different cell lines with CNs-pDNA showed that their biocompatibility was limited and the effects were cell type-dependent

S-Adenosyl-L-Methionine and Cu(II) Impact Green Plant Regeneration Efficiency

The biological improvement of triticale, a cereal of increasing importance in agriculture, may be accelerated via the production of doubled haploid lines using in vitro culture. Among the relevant factors affecting the culture efficiency are Cu(II) or Ag(I) acting, e.g., as cofactors of enzymes. The copper ions are known to positively affect green plant regeneration efficiency. However, the biochemical basis, mainly its role in the generation of in vitro-induced genetic and epigenetic variation and green plant regeneration efficiency, is not well understood. Here, we employed structural equation modeling to evaluate the relationship between de novo DNA methylation affecting the asymmetric context of CHH sequences, the methylation-sensitive Amplified Fragment Length Polymorphism related sequence variation, and the concentration of Cu(II) and Ag(I) ions in induction media, as well as their effect on S-adenosyl-L-methionine perturbations, observed using FTIR spectroscopy, and the green plant regeneration efficiency. Our results allowed the construction of a theory-based model reflecting the biological phenomena associated with green plant regeneration efficiency. Furthermore, it is shown that Cu(II) ions in induction media affect plant regeneration, and by manipulating their concentration, the regeneration efficiency can be altered. Additionally, S-adenosyl-L-methionine is involved in the efficiency of green plant regeneration through methylation of the asymmetric CHH sequence related to de novo methylation. This shows that the Yang cycle may impact the production of green regenerants

Main Barriers to the Introduction of a Home Haemodialysis Programme in Poland: A Review of the Challenges for Implementation and Criteria for a Successful Programme

Introduction: Home dialysis in Poland is restricted to the peritoneal dialysis (PD) modality, with the majority of dialysis patients treated using in-centre haemodialysis (ICHD). Home haemodialysis (HHD) is an additional home therapy to PD and provides an attractive alternative to ICHD that combines dialysis with social distancing; eliminates transportation needs; and offers clinical, economic, and quality of life benefits. However, HHD is not currently provided in Poland. This review was performed to provide an overview of the main barriers to the introduction of a HHD programme in Poland. Main findings: The main high-level barrier to introducing HHD in Poland is the absence of specific health legislation required for clinician prescribing of HHD. Other barriers to overcome include clear definition of reimbursement, patient training and education (including infrastructure and experienced personnel), organisation of logistics, and management of complications. Partnering with a large care network for HHD represents an alternative option to payers for the provision of a new HHD service. This may reduce some of the barriers which need to be overcome when compared with the creation of a new HHD service and its supporting network due to the pre-existing infrastructure, processes, and staff of a large care network. Conclusions: Provision of HHD is not solely about the provision of home treatment, but also the organisation and definition of a range of support services that are required to deliver the service. HHD should be viewed as an additional, complementary option to existing dialysis modalities which enables choice of modality best suited to a patient’s needs

Metabolomic Changes as Key Factors of Green Plant Regeneration Efficiency of Triticale In Vitro Anther Culture

Green plant regeneration efficiency (GPRE) via in vitro anther culture results from biochemical pathways and cycle dysfunctions that may affect DNA and histone methylation, with gene expression influencing whole cell functioning. The reprogramming from gametophytic to sporophytic fate is part of the phenomenon. While DNA methylation and sequence changes related to the GPRE have been described, little attention was paid to the biochemical aspects of the phenomenon. Furthermore, only a few theoretical models that describe the complex relationships between biochemical aspects of GPRE and the role of Cu(II) ions in the induction medium and as cofactors of enzymatic reactions have been developed. Still, none of these models are devoted directly to the biochemical level. Fourier transform infrared (FTIR) spectroscopy was used in the current study to analyze triticale regenerants derived under various in vitro tissue culture conditions, including different Cu(II) and Ag(I) ion concentrations in the induction medium and anther culture times. The FTIR spectra of S-adenosyl-L-methionine (SAM), glutathione, and pectins in parallel with the Cu(II) ions, as well as the evaluated GPRE values, were put into the structural equation model (SEM). The data demonstrate the relationships between SAM, glutathione, pectins, and Cu(II) in the induction medium and how they affect GPRE. The SEM reflects the cell functioning under in vitro conditions and varying Cu(II) concentrations. In the presented model, the players are the Krebs and Yang cycles, the transsulfuration pathway controlled by Cu(II) ions acting as cofactors of enzymatic reactions, and the pectins of the primary cell wall