scholarly journals Flux through lipid synthesis dictates bacterial cell size

2016 ◽  
Author(s):  
Stephen Vadia ◽  
Jessica L. Tse ◽  
Jue D. Wang ◽  
Petra Anne Levin
Keyword(s):  
Cell Size ◽  
Cell Envelope ◽  
Lipid Synthesis ◽  
Dependent Manner ◽  
Top Down ◽  
Cellular Integrity ◽  
Size And Morphology ◽  
Area Expansion ◽  
Open Question ◽  
The Impact

AbstractNutrients—and by extension biosynthetic capacity—positively impact cell size in organisms throughout the tree of life. In bacteria, cell size is reduced three-fold in response to nutrient starvation or accumulation of the alarmone ppGpp, a global inhibitor of biosynthesis. However, whether biosynthetic capacity as a whole determines cell size or if particular anabolic pathways are more important than others remains an open question. Utilizing a top-down approach, here we identify flux through lipid synthesis as the primary biosynthetic determinant ofEscherichia colicell size. Altering flux through lipid synthesis recapitulated the impact of altering nutrients on cell size and morphology, while defects in other biosynthetic pathways either did not impact size or altered size in a lipid-dependent manner. Together our findings support a model in which lipid availability dictates cell envelope capacity and ppGpp functions as a linchpin linking surface area expansion with cytoplasmic volume to maintain cellular integrity.

scholarly journals Contextual control of skin immunity and inflammation by Corynebacterium

2018 ◽  
Vol 215 (3) ◽  
pp. 785-799 ◽  
Author(s):  
Vanessa K. Ridaura ◽  
Nicolas Bouladoux ◽  
Jan Claesen ◽  
Y. Erin Chen ◽  
Allyson L. Byrd ◽  
...  
Keyword(s):  
Immune System ◽  
Cell Envelope ◽  
Γδ T Cells ◽  
Mycolic Acid ◽  
Dependent Manner ◽  
Skin Microbiota ◽  
Skin Immune System ◽  
Dominant Component ◽  
Skin Immunity ◽  
The Impact

How defined microbes influence the skin immune system remains poorly understood. Here we demonstrate that Corynebacteria, dominant members of the skin microbiota, promote a dramatic increase in the number and activation of a defined subset of γδ T cells. This effect is long-lasting, occurs independently of other microbes, and is, in part, mediated by interleukin (IL)-23. Under steady-state conditions, the impact of Corynebacterium is discrete and noninflammatory. However, when applied to the skin of a host fed a high-fat diet, Corynebacterium accolens alone promotes inflammation in an IL-23–dependent manner. Such effect is highly conserved among species of Corynebacterium and dependent on the expression of a dominant component of the cell envelope, mycolic acid. Our data uncover a mode of communication between the immune system and a dominant genus of the skin microbiota and reveal that the functional impact of canonical skin microbial determinants is contextually controlled by the inflammatory and metabolic state of the host.

Spindle scaling mechanisms

2020 ◽  
Vol 64 (2) ◽  
pp. 383-396
Author(s):  
Lara K. Krüger ◽  
Phong T. Tran
Keyword(s):  
Cell Size ◽  
Spindle Assembly ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Size Dependent ◽  
A Cell ◽  
Chromosome Separation ◽  
Spindle Elongation ◽  
Protein Gradients ◽  
Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

VDAC1 Mediated Anticancer Activity of Gallic Acid in Human Lung Adenocarcinoma A549 Cells

2018 ◽  
Vol 18 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Aikebaier Maimaiti ◽  
Amier Aili ◽  
Hureshitanmu Kuerban ◽  
Xuejun Li
Keyword(s):  
Western Blot ◽  
Cell Viability ◽  
Gallic Acid ◽  
Molecular Mechanisms ◽  
A549 Cells ◽  
Dependent Manner ◽  
Lung Carcinoma Cells ◽  
Induced Apoptosis ◽  
The Impact

Aims: Gallic acid (GA) is generally distributed in a variety of plants and foods, and possesses cell growth-inhibiting activities in cancer cell lines. In the present study, the impact of GA on cell viability, apoptosis induction and possible molecular mechanisms in cultured A549 lung carcinoma cells was investigated. Methods: In vitro experiments showed that treating A549 cells with various concentrations of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA inhibits cell viability, comparative proteomic analysis was applied. The changed proteins were identified by Western blot and siRNA methods. Results: Two-dimensional electrophoresis revealed changes that occurred to the cells when treated with or without GA. Four up-regulated protein spots were clearly identified as malate dehydrogenase (MDH), voltagedependent, anion-selective channel protein 1(VDAC1), calreticulin (CRT) and brain acid soluble protein 1(BASP1). VDAC1 in A549 cells was reconfirmed by western blot. Transfection with VDAC1 siRNA significantly increased cell viability after the treatment of GA. Further investigation showed that GA down regulated PI3K/Akt signaling pathways. These data strongly suggest that up-regulation of VDAC1 by GA may play an important role in GA-induced, inhibitory effects on A549 cell viability.

scholarly journals Arginine Decarboxylase Is Essential for Pneumococcal Stress Responses

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 286
Author(s):  
Mary Frances Nakamya ◽  
Moses B. Ayoola ◽  
Leslie A. Shack ◽  
Mirghani Mohamed ◽  
Edwin Swiatlo ◽  
...  
Keyword(s):  
Stress Responses ◽  
Critical Role ◽  
Acid Stress ◽  
Arginine Decarboxylase ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Cellular Processes ◽  
Opportunistic Human Pathogen ◽  
Thiol Peroxidase ◽  
The Impact

Polyamines such as putrescine, cadaverine, and spermidine are small cationic molecules that play significant roles in cellular processes, including bacterial stress responses and host–pathogen interactions. Streptococcus pneumoniae is an opportunistic human pathogen, which causes several diseases that account for significant morbidity and mortality worldwide. As it transits through different host niches, S. pneumoniae is exposed to and must adapt to different types of stress in the host microenvironment. We earlier reported that S. pneumoniae TIGR4, which harbors an isogenic deletion of an arginine decarboxylase (ΔspeA), an enzyme that catalyzes the synthesis of agmatine in the polyamine synthesis pathway, has a reduced capsule. Here, we report the impact of arginine decarboxylase deletion on pneumococcal stress responses. Our results show that ΔspeA is more susceptible to oxidative, nitrosative, and acid stress compared to the wild-type strain. Gene expression analysis by qRT-PCR indicates that thiol peroxidase, a scavenger of reactive oxygen species and aguA from the arginine deiminase system, could be important for peroxide stress responses in a polyamine-dependent manner. Our results also show that speA is essential for endogenous hydrogen peroxide and glutathione production in S. pneumoniae. Taken together, our findings demonstrate the critical role of arginine decarboxylase in pneumococcal stress responses that could impact adaptation and survival in the host.

scholarly journals Inhibition of p38 Mitogen-Activated Protein Kinase Impairs Mayaro Virus Replication in Human Dermal Fibroblasts and HeLa Cells

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1156
Author(s):  
Madelaine Sugasti-Salazar ◽  
Yessica Y. Llamas-González ◽  
Dalkiria Campos ◽  
José González-Santamaría
Keyword(s):  
Protein Expression ◽  
Hela Cells ◽  
Plaque Assay ◽  
Dermal Fibroblasts ◽  
Dependent Manner ◽  
Human Dermal Fibroblasts ◽  
Mitogen Activated Protein ◽  
Mayaro Virus ◽  
The Impact ◽  
Dose Dependent

Mayaro virus (MAYV) hijacks the host’s cell machinery to effectively replicate. The mitogen-activated protein kinases (MAPKs) p38, JNK, and ERK1/2 have emerged as crucial cellular factors implicated in different stages of the viral cycle. However, whether MAYV uses these MAPKs to competently replicate has not yet been determined. The aim of this study was to evaluate the impact of MAPK inhibition on MAYV replication using primary human dermal fibroblasts (HDFs) and HeLa cells. Viral yields in supernatants from MAYV-infected cells treated or untreated with inhibitors SB203580, SP600125, U0126, or Losmapimod were quantified using plaque assay. Additionally, viral protein expression was analyzed using immunoblot and immunofluorescence. Knockdown of p38⍺/p38β isoforms was performed in HDFs using the PROTACs molecule NR-7h. Our data demonstrated that HDFs are highly susceptible to MAYV infection. SB203580, a p38 inhibitor, reduced MAYV replication in a dose-dependent manner in both HDFs and HeLa cells. Additionally, SB203580 significantly decreased viral E1 protein expression. Similarly, knockdown or inhibition of p38⍺/p38β isoforms with NR-7h or Losmapimod, respectively, affected MAYV replication in a dose-dependent manner. Collectively, these findings suggest that p38 could play an important role in MAYV replication and could serve as a therapeutic target to control MAYV infection.

scholarly journals Assessing the impact of previous experience on lie effects through a transfer paradigm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Claudia Mazzuca ◽  
Mariagrazia Benassi ◽  
Roberto Nicoletti ◽  
Giuseppe Sartori ◽  
Luisa Lugli
Keyword(s):  
Training Session ◽  
Spatial Task ◽  
Dual Processes ◽  
Transfer Effects ◽  
Transfer Paradigm ◽  
Compatible Condition ◽  
Open Question ◽  
The Impact ◽  
Cognitive Cost ◽  
Spatial Training

AbstractInfluential lines of research propose dual processes-based explanations to account for both the cognitive cost implied in lying and for that entailed in the resolution of the conflict posited by Simon tasks. The emergence and consistency of the Simon effect has been proved to be modulated by both practice effects and transfer effects. Although several studies provided evidence that the lying cognitive demand may vary as a function of practice, whether and how transfer effects could also play a role remains an open question. We addressed this question with one experiment in which participants completed a Differentiation of Deception Paradigm twice (baseline and test sessions). Crucially, between the baseline and the test sessions, participants performed a training session consisting in a spatial compatibility task with incompatible (condition 1) or compatible (condition 2) mapping, a non-spatial task (condition 3) and a no task one (condition 4). Results speak in favour of a modulation of individual performances by means of an immediate prior experience, and specifically with an incompatible spatial training.

scholarly journals Driver Liability Assessment in Vehicle Collisions in Spain

2021 ◽  
Vol 18 (4) ◽  
pp. 1475
Author(s):  
Almudena Sanjurjo-de-No ◽  
Blanca Arenas-Ramírez ◽  
José Mira ◽  
Francisco Aparicio-Izquierdo
Keyword(s):  
Road Safety ◽  
Accurate Estimation ◽  
Main Hypothesis ◽  
Self Organizing Maps ◽  
Safety Measures ◽  
Vehicle Collisions ◽  
Promising Tool ◽  
Visual Clustering ◽  
Open Question ◽  
The Impact

An accurate estimation of exposure is essential for road collision rate estimation, which is key when evaluating the impact of road safety measures. The quasi-induced exposure method was developed to estimate relative exposure for different driver groups based on its main hypothesis: the not-at-fault drivers involved in two-vehicle collisions are taken as a random sample of driver populations. Liability assignment is thus crucial in this method to identify not-at-fault drivers, but often no liability labels are given in collision records, so unsupervised analysis tools are required. To date, most researchers consider only driver and speed offences in liability assignment, but an open question is if more information could be added. To this end, in this paper, the visual clustering technique of self-organizing maps (SOM) has been applied to better understand the multivariate structure in the data, to find out the most important variables for driver liability, analyzing their influence, and to identify relevant liability patterns. The results show that alcohol/drug use could be influential on liability and further analysis is required for disability and sudden illness. More information has been used, given that a larger proportion of the data was considered. SOM thus appears as a promising tool for liability assessment.

scholarly journals The Influence of Diet and Sex on the Gut Microbiota of Lean and Obese JCR:LA-cp Rats

2021 ◽  
Vol 9 (5) ◽  
pp. 1037
Author(s):  
Craig Resch ◽  
Mihir Parikh ◽  
J. Alejandro Austria ◽  
Spencer D. Proctor ◽  
Thomas Netticadan ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Control Diet ◽  
Bacterial Species ◽  
Alpha Diversity ◽  
Short Chain Fatty Acids ◽  
Female Rats ◽  
Dependent Manner ◽  
Male And Female ◽  
Ground Flaxseed ◽  
The Impact

There is an increased interest in the gut microbiota as it relates to health and obesity. The impact of diet and sex on the gut microbiota in conjunction with obesity also demands extensive systemic investigation. Thus, the influence of sex, diet, and flaxseed supplementation on the gut microbiota was examined in the JCR:LA-cp rat model of genetic obesity. Male and female obese rats were randomized into four groups (n = 8) to receive, for 12 weeks, either (a) control diet (Con), (b) control diet supplemented with 10% ground flaxseed (CFlax), (c) a high-fat, high sucrose (HFHS) diet, or (d) HFHS supplemented with 10% ground flaxseed (HFlax). Male and female JCR:LA-cp lean rats served as genetic controls and received similar dietary interventions. Illumine MiSeq sequencing revealed a richer microbiota in rats fed control diets rather than HFHS diets. Obese female rats had lower alpha-diversity than lean female; however, both sexes of obese and lean JCR rats differed significantly in β-diversity, as their gut microbiota was composed of different abundances of bacterial types. The feeding of an HFHS diet affected the diversity by increasing the phylum Bacteroidetes and reducing bacterial species from phylum Firmicutes. Fecal short-chain fatty acids such as acetate, propionate, and butyrate-producing bacterial species were correspondingly impacted by the HFHS diet. Flax supplementation improved the gut microbiota by decreasing the abundance of Blautia and Eubacterium dolichum. Collectively, our data show that an HFHS diet results in gut microbiota dysbiosis in a sex-dependent manner. Flaxseed supplementation to the diet had a significant impact on gut microbiota diversity under both flax control and HFHS dietary conditions.

scholarly journals Petasin and isopetasin reduce CGRP release from trigeminal afferents indicating an inhibitory effect on TRPA1 and TRPV1 receptor channels

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Johanna Kleeberg-Hartmann ◽  
Birgit Vogler ◽  
Karl Messlinger
Keyword(s):  
Inhibitory Effect ◽  
Transient Receptor Potential Channels ◽  
Mustard Oil ◽  
Root Extract ◽  
Dependent Manner ◽  
Trpv1 Receptor ◽  
Cgrp Release ◽  
Ganglion Neurons ◽  
Sites Of Action ◽  
The Impact

Abstract Background Butterbur root extract with its active ingredients petasin and isopetasin has been used in the prophylactic treatment of migraine for years, while its sites of action are not completely clear. Calcitonin gene-related peptide (CGRP) is known as a biomarker and promoting factor of migraine. We set out to investigate the impact of petasins on the CGRP release from trigeminal afferents induced by activation of the calcium conducting transient receptor potential channels (TRPs) of the subtypes TRPA1 and TRPV1. Methods We used well-established in vitro preparations, the hemisected rodent skull and dissected trigeminal ganglia, to examine the CGRP release from rat and mouse cranial dura mater and trigeminal ganglion neurons, respectively, after pre-incubation with petasin and isopetasin. Mustard oil and capsaicin were used to stimulate TRPA1 and TRPV1 receptor channels. CGRP concentrations were measured with a CGRP enzyme immunoassay. Results Pre-incubation with either petasin or isopetasin reduced mustard oil- and capsaicin-evoked CGRP release compared to vehicle in an approximately dose-dependent manner. These results were validated by additional experiments with mice expressing functionally deleted TRPA1 or TRPV1 receptor channels. Conclusions Earlier findings of TRPA1 receptor channels being involved in the site of action of petasin and isopetasin are confirmed. Furthermore, we suggest an important inhibitory effect on TRPV1 receptor channels and assume a cooperative action between the two TRP receptors. These mechanisms may contribute to the migraine prophylactic effect of petasins.

scholarly journals Reduced beta cell number rather than size is a major contributor to beta cell loss in type 2 diabetes

Diabetologia ◽  
2021 ◽  
Author(s):  
Hironobu Sasaki ◽  
Yoshifumi Saisho ◽  
Jun Inaishi ◽  
Yuusuke Watanabe ◽  
Tami Tsuchiya ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Beta Cell ◽  
Cell Size ◽  
Cell Mass ◽  
Cell Number ◽  
Relative Reduction ◽  
Major Contributor ◽  
Islet Morphology ◽  
The Impact

Abstract Aims/hypothesis Type 2 diabetes is characterised by reduced beta cell mass (BCM). However, it remains uncertain whether the reduction in BCM in type 2 diabetes is due to a decrease in size or number of beta cells. Our aim was to examine the impact of beta cell size and number on islet morphology in humans with and without type 2 diabetes. Methods Pancreas samples were obtained from 64 Japanese adults with (n = 26) and without (n = 38) type 2 diabetes who underwent pancreatectomy. Using pancreatic tissues stained for insulin, we estimated beta cell size based on beta cell diameter. Beta cell number was estimated from the product of fractional beta cell area and pancreas volume divided by beta cell size. The associations of beta cell size and number with islet morphology and metabolic status were examined. Results Both beta cell size (548.7 ± 58.5 vs 606.7 ± 65.0 μm3, p < 0.01) and number (5.10 × 108 ± 2.35 × 108 vs 8.16 × 108 ± 4.27 × 108, p < 0.01) were decreased in participants with type 2 diabetes compared with those without diabetes, with the relative reduction in beta cell number (37%) being greater than for beta cell size (10%). Beta cell number but not size was positively correlated with BCM in participants with and without type 2 diabetes (r = 0.97 and r = 0.98, both p < 0.01) and negatively correlated with HbA1c (r = −0.45, p < 0.01). Conclusions/interpretation Both beta cell size and number were reduced in participants with type 2 diabetes, with the relative reduction in beta cell number being greater. Decrease in beta cell number appears to be a major contributor to reduced BCM in type 2 diabetes. Graphical abstract

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