scholarly journals Proteomic Insights into Starvation of Nitrogen-Replete Cells of Nostoc sp. PCC 7120 under β-N-Methylamino-L-Alanine (BMAA) Treatment

Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 372
Author(s):  
Olga A. Koksharova ◽  
Ivan O. Butenko ◽  
Olga V. Pobeguts ◽  
Nina A. Safronova ◽  
Vadim M. Govorun
Keyword(s):  
Molecular Mechanisms ◽  
Nitrogen Starvation ◽  
Regulatory Protein ◽  
Nitrogen Deficiency ◽  
Regulatory Proteins ◽  
Pii Protein ◽  
Significant Difference ◽  
Pcc 7120 ◽  
Nitrogen Excess ◽  
Starvation Conditions

All cyanobacteria produce a neurotoxic non-protein amino acid β-N-methylamino-L-alanine (BMAA). However, the biological function of BMAA in the regulation of cyanobacteria metabolism still remains undetermined. It is known that BMAA suppresses the formation of heterocysts in diazotrophic cyanobacteria under nitrogen starvation conditions, and BMAA induces the formation of heterocyst-like cells under nitrogen excess conditions, by causing the expression of heterocyst-specific genes that are usually “silent” under nitrogen-replete conditions, as if these bacteria receive a nitrogen deficiency intracellular molecular signal. In order to find out the molecular mechanisms underlying this unexpected BMAA effect, we studied the proteome of cyanobacterium Nostoc sp. PCC 7120 grown under BMAA treatment in nitrogen-replete medium. Experiments were performed in two experimental settings: (1) in control samples consisted of cells grown without the BMAA treatment and (2) the treated samples consisted of cells grown with addition of an aqueous solution of BMAA (20 µM). In total, 1567 different proteins of Nostoc sp. PCC 7120 were identified by LC-MS/MS spectrometry. Among them, 80 proteins belonging to different functional categories were chosen for further functional analysis and interpretation of obtained proteomic data. Here, we provide the evidence that a pleiotropic regulatory effect of BMAA on the proteome of cyanobacterium was largely different under conditions of nitrogen-excess compared to its effect under nitrogen starvation conditions (that was studied in our previous work). The most significant difference in proteome expression between the BMAA-treated and untreated samples under different growth conditions was detected in key regulatory protein PII (GlnB). BMAA downregulates protein PII in nitrogen-starved cells and upregulates this protein in nitrogen-replete conditions. PII protein is a key signal transduction protein and the change in its regulation leads to the change of many other regulatory proteins, including different transcriptional factors, enzymes and transporters. Complex changes in key metabolic and regulatory proteins (RbcL, RbcS, Rca, CmpA, GltS, NodM, thioredoxin 1, RpbD, ClpP, MinD, RecA, etc.), detected in this experimental study, could be a reason for the appearance of the “starvation” state in nitrogen-replete conditions in the presence of BMAA. In addition, 15 proteins identified in this study are encoded by genes, which are under the control of NtcA—a global transcriptional regulator—one of the main protein partners and transcriptional regulators of PII protein. Thereby, this proteomic study gives a possible explanation of cyanobacterium starvation under nitrogen-replete conditions and BMAA treatment. It allows to take a closer look at the regulation of cyanobacteria metabolism affected by this cyanotoxin.

scholarly journals HetR-Dependent and -Independent Expression of Heterocyst-Related Genes in an Anabaena Strain Overproducing the NtcA Transcription Factor

2005 ◽  
Vol 187 (6) ◽  
pp. 1985-1991 ◽  
Author(s):  
Elvira Olmedo-Verd ◽  
Enrique Flores ◽  
Antonia Herrero ◽  
Alicia M. Muro-Pastor
Keyword(s):  
Transcription Factor ◽  
Cell Differentiation ◽  
Nitrogen Source ◽  
Regulatory Protein ◽  
Nitrogen Deficiency ◽  
Nitrogen Control ◽  
Heterocyst Differentiation ◽  
Step Down ◽  
Pcc 7120 ◽  
Heterocyst Development

ABSTRACT Heterocyst development in the cyanobacterium Anabaena sp. strain PCC 7120 depends on both the global nitrogen control transcription factor NtcA and the cell differentiation regulatory protein HetR, with expression of ntcA and hetR being dependent on each other. In this study we constructed strains that constitutively express the ntcA gene leading to high levels of NtcA protein irrespective of the nitrogen source, and we analyzed the effects of such NtcA levels on heterocyst differentiation. In the NtcA-overproducing strain, heterocyst differentiation, induction of NtcA-dependent heterocyst development genes or operons such as devBCA or the cox2 operon, and NtcA-dependent excision of the 11-kb nifD-intervening element only took place under nitrogen deficiency. Although functional heterocysts were produced in response to nitrogen step-down, the NtcA overproducing strain could not grow diazotrophically. Overexpression of ntcA in a hetR background promoted expression of devBCA in response to ammonium withdrawal and excision of the 11-kb element even in the presence of combined nitrogen. Our results show that some NtcA-dependent heterocyst-related genes can be expressed independently of HetR.

scholarly journals Physiological and Comparative Transcriptomic Analysis Provide Insight Into Cotton (Gossypium hirsutum L.) Root Senescence in Response

2021 ◽  
Vol 12 ◽  
Author(s):  
Lingxiao Zhu ◽  
Liantao Liu ◽  
Hongchun Sun ◽  
Yongjiang Zhang ◽  
Jijie Zhu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Nitrogen Starvation ◽  
Nitrogen Deficiency ◽  
Transcriptomic Analysis ◽  
Differentially Expressed ◽  
Root Senescence ◽  
Nitrogen Treatments ◽  
Normal Nitrogen ◽  
The Impact ◽  
Low Nitrogen

Nitrogen (N) deficiency is one of the pivotal environmental factors that induce leaf senescence. However, little is known regarding the impact of low N on root senescence in cotton. Thus, the objective of this study was to investigate the effect of low nitrogen on root senescence. In this study, the molecular mechanism of cotton root senescence in response to nitrogen deficiency was investigated by combing physiological and transcriptomic analysis when no nitrogen and normal nitrogen (138mg N·kg−1 soil). The results showed that: (1) nitrogen starvation induced the premature senescence of leaf, while delaying root senescence. (2) The increase in catalase (CAT) activity at 60, 80, and 100days after emergence (DAE), combined with decrease of malonaldehyde content at 60, 80, and 100 DAE, and the content of abscisic acid (ABA), all of these contributed to the delay of root senescence by low nitrogen treatment. (3) To study the molecular mechanisms underlying root senescence, the gene expression profiling between low nitrogen and normal nitrogen treatments were compared pairwise at 20, 40, 60, 80, and 100 DAE. A total of 14,607 genes were identified to be differentially expressed at these five points. (5) Most genes involved in glutathione (GSH) and ascorbate peroxidase (APX) synthesis were upregulated, while ABA, apoptosis, caspase, and cell cycle-related differentially expressed genes (DEGs) were downregulated. Coupled with the physiology data, these results provide new insights into the effect of nitrogen starvation on root senescence.

scholarly journals The Effect of Alcohol on Telomere Length: A Systematic Review of Epidemiological Evidence and a Pilot Study during Pregnancy

2021 ◽  
Vol 18 (9) ◽  
pp. 5038
Author(s):  
Andrea Maugeri ◽  
Martina Barchitta ◽  
Roberta Magnano San Lio ◽  
Maria Clara La Rosa ◽  
Claudia La Mastra ◽  
...  
Keyword(s):  
Systematic Review ◽  
Pilot Study ◽  
Alcohol Consumption ◽  
Telomere Length ◽  
Molecular Mechanisms ◽  
Epidemiological Studies ◽  
Potential Association ◽  
Significant Difference ◽  
Periconceptional Period ◽  
Using Data

Several studies—albeit with still inconclusive and limited findings—began to focus on the effect of drinking alcohol on telomere length (TL). Here, we present results from a systematic review of these epidemiological studies to investigate the potential association between alcohol consumption, alcohol-related disorders, and TL. The analysis of fourteen studies—selected from PubMed, Medline, and Web of Science databases—showed that people with alcohol-related disorders exhibited shorter TL, but also that alcohol consumption per se did not appear to affect TL in the absence of alcohol abuse or dependence. Our work also revealed a lack of studies in the periconceptional period, raising the need for evaluating this potential relationship during pregnancy. To fill this gap, we conducted a pilot study using data and samples form the Mamma & Bambino cohort. We compared five non-smoking but drinking women with ten non-smoking and non-drinking women, matched for maternal age, gestational age at recruitment, pregestational body mass index, and fetal sex. Interestingly, we detected a significant difference when analyzing relative TL of leukocyte DNA of cord blood samples from newborns. In particular, newborns from drinking women exhibited shorter relative TL than those born from non-drinking women (p = 0.024). Although these findings appeared promising, further research should be encouraged to test any dose–response relationship, to adjust for the effect of other exposures, and to understand the molecular mechanisms involved.

Screening of cervical cancer-related hub genes based on comprehensive bioinformatics analysis

2021 ◽  
pp. 1-13
Author(s):  
Simei Tu ◽  
Hao Zhang ◽  
Xiaocheng Yang ◽  
Wen Wen ◽  
Kangjing Song ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cervical Cancer ◽  
Molecular Mechanisms ◽  
Disease Free Survival ◽  
The Cancer Genome Atlas ◽  
Mrna Levels ◽  
Hub Genes ◽  
Normal Tissues ◽  
Significant Difference ◽  
Core Genes

BACKGROUND: Since the molecular mechanisms of cervical cancer (CC) have not been completely discovered, it is of great significance to identify the hub genes and pathways of this disease to reveal the molecular mechanisms of cervical cancer. OBJECTIVE: The study aimed to identify the biological functions and prognostic value of hub genes in cervical cancer. METHODS: The gene expression data of CC patients were downloaded from the Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA) database. The core genes were screened out by differential gene expression analysis and weighted gene co-expression network analysis (WGCNA). R software, the STRING online tool and Cytoscape software were used to screen out the hub genes. The GEPIA public database was used to further verify the expression levels of the hub genes in normal tissues and tumour tissues and determine the disease-free survival (DFS) rates of the hub genes. The protein expression of the survival-related hub genes was identified with the Human Protein Atlas (HPA) database. RESULTS: A total of 64 core genes were screened, and 10 genes, including RFC5, POLE3, RAD51, RMI1, PALB2, HDAC1, MCM4, ESR1, FOS and E2F1, were identified as hub genes. Compared with that in normal tissues, RFC5, POLE3, RAD51,RMI1, PALB2, MCM4 and E2F1 were all significantly upregulated in cervical cancer, ESR1 was significantly downregulated in cervical cancer, and high RFC5 expression in CC patients was significantly related to OS. In the DFS analysis, no significant difference was observed in the expression level of RFC5 in cervical cancer patients. Finally, RFC5 protein levels verified by the HPA database were consistently upregulated with mRNA levels in CC samples. CONCLUSIONS: RFC5 may play important roles in the occurrence and prognosis of CC. It could be further explored and validated as a potential predictor and therapeutic target for CC.

scholarly journals Binding of aldolase to actin-containing filaments. Evidence of interaction with the regulatory proteins of skeletal muscle

1980 ◽  
Vol 186 (1) ◽  
pp. 89-98 ◽  
Author(s):  
T P Walsh ◽  
D J Winzor ◽  
F M Clarke ◽  
C J Masters ◽  
D J Morton
Keyword(s):  
Skeletal Muscle ◽  
Binding Constant ◽  
Moving Boundary ◽  
Regulatory Protein ◽  
Regulatory Proteins ◽  
Affinity Constant ◽  
Quantitative Studies ◽  
Multiple Binding Sites ◽  
Multiple Binding ◽  
Troponin Complex

The interactions of aldolase with regulatory proteins of rabbit skeletal muscle were investigated by moving-boundary electrophoresis. A salt-dependent interaction of troponin, tropomyosin and the tropomyosin-troponin complex with aldolase was detected, the tropomyosin-troponin complex displaying a greater affinity for the enzyme than did either regulatory protein alone. The results indicate that aldolase possesses multiple binding sites (three or more) for these muscle proteins. Quantitative studies of the binding of aldolase to actin-containing filaments showed the interaction to be influenced markedly by the presence of these muscle regulatory proteins on the filaments. In imidazole/HCl buffer, I 0.088, pH 6.8, aldolase binds to F-actin with an affinity constant of 2 × 10(5) M-1 and a stoicheiometry of one tetrameric aldolase molecule per 14 monomeric actin units. Use of F-actin-tropomyosin as adsorbent results in a doubling of the stoicheiometry without significant change in the intrinsic association constant. With F-actin-tropomyosin-troponin a lower binding constant (6 × 10(4) M-1) but even greater stoicheiometry (4:14 actin units) are observed. The presence of Ca2+ (0.1 mM) decreases this stoicheiometry to 3:14 without affecting significantly the magnitude of the intrinsic binding constant.

scholarly journals Candida Albicans ERG11 Gene Polymorphism: Impact on Its In Vivo Virulence and Susceptibility to Fluconazole According to the Galleria Mellonella Model

2021 ◽  
Author(s):  
Marcel Patindoilba Sawadogo ◽  
Adama Zida ◽  
Issiaka Soulama ◽  
Samuel S Sermé ◽  
Thierry Kiswendsida Guiguemdé ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Molecular Mechanisms ◽  
Reference Strain ◽  
Galleria Mellonella ◽  
Larval Mortality ◽  
Fungal Burden ◽  
Significant Difference ◽  
Strain Sc5314 ◽  
Resistant Strains

The aim of this study is to have an idea on the molecular mechanisms of C. albicans resistance to fluconazole in Burkina Faso, by studying the polymorphism of the ERG11 gene, and its implication in the C. albicans virulence and resistance in vivo according to the Galleria mellonella model; (2) Methods: Ten (10) clinical strains including, 5 resistant and 5 susceptible and 1 virulent and susceptible reference strain SC5314 are used. For the estimation of virulence, the larvae were inoculated with 10 μL of C. albicans cell suspension at variable concentrations: 2,5.105, 5.105, 1.106, and 5.106 CFU/larva of each strain. For the in vivo efficacy study, fluconazole was administered at 1, 4 and 16 mg/kg respectively to G. mellonella larvae, after infection by inoculum 5.106 CFU / larvae of each strain; (3) Results: Six (6) non-silent mutations in the ERG11 gene (K143R, F145L, G307S, S405F, G448E, V456I on ERG11p) were found in 4 resistant isolates. Larval mortality depended on fungal burden and strain. The inoculum 5.106 CFU caused 100% mortality in 2 days for the 2 CAAL-1 and CAAL-2 strains carrying the F145L mutation, in 3 days for the reference strain SC5314, in 4 days for the ensemble of resistant strains, and in 5 days for the ensemble of susceptible strains. The comparison of the mortality due to the reference strain SC5314 CFU / larva and the average mortality due to the two mutant F145L strains, shows a significant difference (P <0.05).Fluconazole significantly protected (P> 0.05) the larvae from infection by susceptible strains and the reference strain. However, 100% mortality in 6 days after injection of the resistant strains, was observed (4) Conclusions: Certain mutations in the ERG11 gene such as the F145L mutation are thought to be a source of increased virulence in Candida albicans. Fluconazole effectively protected larvae from infection by susceptible strains in vivo, unlike resistant strain

scholarly journals Nitrogen starvation and stationary phase lipophagy have distinct molecular mechanisms

2020 ◽  
Author(s):  
Ravinder Kumar ◽  
Muhammad Arifur Rahman ◽  
Taras Y. Nazarko
Keyword(s):  
Lipid Droplets ◽  
Molecular Mechanisms ◽  
Nitrogen Starvation ◽  
S Phase ◽  
Carbon Limitation ◽  
Intracellular Lipid ◽  
Selective Autophagy ◽  
The Core ◽  
Vacuole Fusion ◽  
N Starvation

AbstractIn yeast, the selective autophagy of intracellular lipid droplets (LDs) or lipophagy can be induced by either nitrogen (N) starvation or carbon limitation (e.g. in the stationary (S) phase). We developed the yeast, Komagataella phaffii (formerly Pichia pastoris), as a new lipophagy model and compared the N-starvation and S-phase lipophagy in over 30 autophagy-related mutants using the Erg6-GFP processing assay. Surprisingly, two lipophagy pathways had hardly overlapping stringent molecular requirements. While the N-starvation lipophagy strictly depended on the core autophagic machinery (Atg1-Atg9, Atg18 and Vps15), vacuole fusion machinery (Vam7 and Ypt7) and vacuolar proteolysis (proteinases A and B), only Atg6 and proteinases A and B were essential for the S-phase lipophagy. The rest of the proteins were only partially required in the S-phase. Moreover, we isolated the prl1 (for positive regulator of lipophagy 1) mutant affected in the S-phase lipophagy but not N-starvation lipophagy. The prl1 defect was at a stage of delivery of the LDs from the cytoplasm to the vacuole further supporting mechanistically different nature of the two lipophagy pathways. Taken together, our results suggest that N-starvation and S-phase lipophagy have distinct molecular mechanisms.

scholarly journals Identification of key genes and associated pathways in neuroendocrine tumors through bioinformatics analysis and predictions of small drug molecules

2020 ◽  
Author(s):  
Praveenkumar Devarbhavi ◽  
Basavaraj Vastrad ◽  
Anandkumar Tengli ◽  
Chanabasayya Vastrad ◽  
Iranna Kotturshetti
Keyword(s):  
Drug Target ◽  
Target Gene ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Regulatory Elements ◽  
Future Research ◽  
High Morbidity ◽  
Hub Genes ◽  
Go Enrichment ◽  
Significant Difference

AbstractNeuroendocrine tumor (NET) is one of malignant cancer and is identified with high morbidity and mortality rates around the world. With indigent clinical outcomes, potential biomarkers for diagnosis, prognosis and drug target are crucial to explore. The aim of this study is to examine the gene expression module of NET and to identify potential diagnostic and prognostic biomarkers as well as to find out new drug target. The differentially expressed genes (DEGs) identified from GSE65286 dataset was used for pathway enrichment analyses and gene ontology (GO) enrichment analyses and protein - protein interaction (PPI) analysis and module analysis. Moreover, miRNAs and transcription factors (TFs) that regulated the up and down regulated genes were predicted. Furthermore, validation of hub genes was performed. Finally, molecular docking studies were performed. DEGs were identified, including 453 down regulated and 459 up regulated genes. Pathway and GO enrichment analysis revealed that DEGs were enriched in sucrose degradation, creatine biosynthesis, anion transport and modulation of chemical synaptic transmission. Important hub genes and target genes were identified through PPI network, modules, target gene - miRNA network and target gene - TF network. Finally, survival analyses, receiver operating characteristic (ROC) curve and RT-PCR validated the significant difference of ATP1A1, LGALS3, LDHA, SYK, VDR, OBSL1, KRT40, WWOX, NINL and PPP2R2B between metastatic NET and normal controls. In conclusion, the DEGs and hub genes with their regulatory elements identified in this study will help us understand the molecular mechanisms underlying NET and provide candidate targets for future research.

scholarly journals NtcA-Dependent Expression of the devBCAOperon, Encoding a Heterocyst-Specific ATP-Binding Cassette Transporter in Anabaena spp

2001 ◽  
Vol 183 (12) ◽  
pp. 3795-3799 ◽  
Author(s):  
Gabriele Fiedler ◽  
Alicia M. Muro-Pastor ◽  
Enrique Flores ◽  
Iris Maldener
Keyword(s):  
Nitrogen Deficiency ◽  
Transcriptional Regulator ◽  
Atp Binding ◽  
Translation Start Site ◽  
Atp Binding Cassette Transporter ◽  
Translation Start ◽  
Transcriptional Start Point ◽  
Pcc 7120 ◽  
Atp Binding Cassette

ABSTRACT The devBCA operon, encoding subunits of an ATP-binding cassette exporter, is essential for differentiation of N2-fixing heterocysts in Anabaena spp. Nitrogen deficiency-dependent transcription of the operon and the use of its transcriptional start point, located 762 (Anabaena variabilis strain ATCC 29413-FD) or 704 (Anabaena sp. strain PCC 7120) bp upstream of the translation start site, were found to require the global nitrogen transcriptional regulator NtcA. Furthermore, NtcA was shown to bind in vitro to the promoter ofdevBCA.

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