scholarly journals Bacterial lifestyle switch in response to algal metabolites

2022 ◽  
Author(s):  
Noa Barak-Gavish ◽  
Bareket Dassa ◽  
Constanze Kuhlisch ◽  
Inbal Nussbaum ◽  
Gili Rosenberg ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Heterotrophic Bacteria ◽  
Transport Systems ◽  
Physiological Status ◽  
Flagellar Motility ◽  
Marine Food Webs ◽  
Unicellular Algae ◽  
Algal Host ◽  
Metabolic Basis ◽  
Metabolic Exchange

Unicellular algae, termed phytoplankton, greatly impact the marine environment by serving as the basis of marine food webs and by playing central roles in biogeochemical cycling of elements. The interactions between phytoplankton and heterotrophic bacteria affect the fitness of both partners. It is becoming increasingly recognized that metabolic exchange determines the nature of such interactions, but the underlying molecular mechanisms remain underexplored. Here, we investigated the molecular and metabolic basis for the bacterial lifestyle switch, from coexistence to pathogenicity, in Sulfitobacter D7 during its interaction with Emiliania huxleyi, a cosmopolitan bloom-forming phytoplankter. To unravel the bacterial lifestyle switch, we profiled bacterial transcriptomes in response to infochemicals derived from algae in exponential and stationary growth, which induced the Sulfitobacter D7 coexistence and pathogenicity lifestyles, respectively. We found that algal dimethylsulfoniopropionate (DMSP) was a pivotal signaling molecule that mediated the transition between the lifestyles. However, the coexisting and pathogenic lifestyles were evident only in the presence of additional algal metabolites. In the pathogenic mode, Sulfitobacter D7 upregulated flagellar motility and many transport systems, presumably to maximize assimilation of E. huxleyi-derived metabolites released by algal cells upon cell death. Specifically, we discovered that algae-produced benzoate promoted the growth of Sulfitobacter D7, and negated the DMSP-inducing lifestyle switch to pathogenicity, demonstrating that benzoate is important for maintaining the coexistence of algae and bacteria. We propose that bacteria can sense the physiological status of the algal host through changes in the metabolic composition, which will determine the bacterial lifestyle during the interactions.

scholarly journals More, smaller bacteria in response to ocean's warming?

2015 ◽  
Vol 282 (1810) ◽  
pp. 20150371 ◽  
Author(s):  
Xosé Anxelu G. Morán ◽  
Laura Alonso-Sáez ◽  
Enrique Nogueira ◽  
Hugh W. Ducklow ◽  
Natalia González ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Total Biomass ◽  
Marine Food Webs ◽  
Flow Cytometric ◽  
Short Period ◽  
Major Shift ◽  
Temperature Manipulation ◽  
Atlantic Coastal ◽  
Individual Size ◽  
Interannual Scale

Heterotrophic bacteria play a major role in organic matter cycling in the ocean. Although the high abundances and relatively fast growth rates of coastal surface bacterioplankton make them suitable sentinels of global change, past analyses have largely overlooked this functional group. Here, time series analysis of a decade of monthly observations in temperate Atlantic coastal waters revealed strong seasonal patterns in the abundance, size and biomass of the ubiquitous flow-cytometric groups of low (LNA) and high nucleic acid (HNA) content bacteria. Over this relatively short period, we also found that bacterioplankton cells were significantly smaller, a trend that is consistent with the hypothesized temperature-driven decrease in body size. Although decadal cell shrinking was observed for both groups, it was only LNA cells that were strongly coherent, with ecological theories linking temperature, abundance and individual size on both the seasonal and interannual scale. We explain this finding because, relative to their HNA counterparts, marine LNA bacteria are less diverse, dominated by members of the SAR11 clade. Temperature manipulation experiments in 2012 confirmed a direct effect of warming on bacterial size. Concurrent with rising temperatures in spring, significant decadal trends of increasing standing stocks (3% per year) accompanied by decreasing mean cell size (−1% per year) suggest a major shift in community structure, with a larger contribution of LNA bacteria to total biomass. The increasing prevalence of these typically oligotrophic taxa may severely impact marine food webs and carbon fluxes by an overall decrease in the efficiency of the biological pump.

scholarly journals Signal Peptide-Dependent Protein Transport inBacillus subtilis: a Genome-Based Survey of the Secretome

2000 ◽  
Vol 64 (3) ◽  
pp. 515-547 ◽  
Author(s):  
Harold Tjalsma ◽  
Albert Bolhuis ◽  
Jan D. H. Jongbloed ◽  
Sierd Bron ◽  
Jan Maarten van Dijl
Keyword(s):  
Protein Secretion ◽  
Molecular Mechanisms ◽  
Protein Transport ◽  
Transport Systems ◽  
Future Research ◽  
Yeast Saccharomyces Cerevisiae ◽  
Transport Pathways ◽  
Amino Terminal ◽  
Cell Factories ◽  
A Genome

SUMMARY One of the most salient features of Bacillus subtilis and related bacilli is their natural capacity to secrete a variety of proteins into their environment, frequently to high concentrations. This has led to the commercial exploitation of bacilli as major “cell factories” for secreted enzymes. The recent sequencing of the genome of B. subtilis has provided major new impulse for analysis of the molecular mechanisms underlying protein secretion by this organism. Most importantly, the genome sequence has allowed predictions about the composition of the secretome, which includes both the pathways for protein transport and the secreted proteins. The present survey of the secretome describes four distinct pathways for protein export from the cytoplasm and approximately 300 proteins with the potential to be exported. By far the largest number of exported proteins are predicted to follow the major “Sec” pathway for protein secretion. In contrast, the twin-arginine translocation “Tat” pathway, a type IV prepilin-like export pathway for competence development, and ATP-binding cassette transporters can be regarded as “special-purpose” pathways, through which only a few proteins are transported. The properties of distinct classes of amino-terminal signal peptides, directing proteins into the various protein transport pathways, as well as the major components of each pathway are discussed. The predictions and comparisons in this review pinpoint important differences as well as similarities between protein transport systems in B. subtilis and other well-studied organisms, such as Escherichia coli and the yeast Saccharomyces cerevisiae. Thus, they may serve as a lead for future research and applications.

scholarly journals STIM1 Deficiency Leads to Specific Down-Regulation of ITPR3 in SH-SY5Y Cells

2020 ◽  
Vol 21 (18) ◽  
pp. 6598
Author(s):  
Carlos Pascual-Caro ◽  
Yolanda Orantos-Aguilera ◽  
Irene Sanchez-Lopez ◽  
Jaime de Juan-Sanz ◽  
Jan B. Parys ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Ectopic Expression ◽  
Neuronal Cell ◽  
Atp Synthesis ◽  
Transport Systems ◽  
Synthesis Rate ◽  
Physical Interaction ◽  
Excitable Cells ◽  
Protein Levels

STIM1 is an endoplasmic reticulum (ER) protein that modulates the activity of a number of Ca2+ transport systems. By direct physical interaction with ORAI1, a plasma membrane Ca2+ channel, STIM1 activates the ICRAC current, whereas the binding with the voltage-operated Ca2+ channel CaV1.2 inhibits the current through this latter channel. In this way, STIM1 is a key regulator of Ca2+ signaling in excitable and non-excitable cells, and altered STIM1 levels have been reported to underlie several pathologies, including immunodeficiency, neurodegenerative diseases, and cancer. In both sporadic and familial Alzheimer’s disease, a decrease of STIM1 protein levels accounts for the alteration of Ca2+ handling that compromises neuronal cell viability. Using SH-SY5Y cells edited by CRISPR/Cas9 to knockout STIM1 gene expression, this work evaluated the molecular mechanisms underlying the cell death triggered by the deficiency of STIM1, demonstrating that STIM1 is a positive regulator of ITPR3 gene expression. ITPR3 (or IP3R3) is a Ca2+ channel enriched at ER-mitochondria contact sites where it provides Ca2+ for transport into the mitochondria. Thus, STIM1 deficiency leads to a strong reduction of ITPR3 transcript and ITPR3 protein levels, a consequent decrease of the mitochondria free Ca2+ concentration ([Ca2+]mit), reduction of mitochondrial oxygen consumption rate, and decrease in ATP synthesis rate. All these values were normalized by ectopic expression of ITPR3 in STIM1-KO cells, providing strong evidence for a new mode of regulation of [Ca2+]mit mediated by the STIM1-ITPR3 axis.

STUDIES ON GLYCINE-PERCOLATED SOIL: I. CORRELATION BETWEEN GLYCINE OXIDATION AND BACTERIAL POPULATION

1965 ◽  
Vol 43 (7) ◽  
pp. 1017-1027 ◽  
Author(s):  
C. Furusaka ◽  
K. Sato
Keyword(s):  
Organic Matter ◽  
Bacterial Population ◽  
Heterotrophic Bacteria ◽  
Close Correlation ◽  
Soil Conditions ◽  
Physiological Status ◽  
Soil Processes ◽  
Population Number ◽  
Soil Percolation ◽  
Number Of Bacteria

It is of interest to determine how the soil percolation technique may be of use for the elucidation of soil processes from the microbiological viewpoint as well as from the biochemical one. An attempt has been made to correlate the growth of heterotrophic bacteria with their chemical activities when soil is percolated with glycine solution. A very close correlation has been observed between the population number of bacteria and their glycine–oxidizing activity. The physiological status of the population has been investigated. The metabolism of soil organic matter is also induced by the glycine percolation. The soil conditions under which the bacterial population can be considered in connection with their activities are discussed.

scholarly journals Mechanisms of phagocytosis and host clearance ofPseudomonas aeruginosa

2014 ◽  
Vol 306 (7) ◽  
pp. L591-L603 ◽  
Author(s):  
Rustin R. Lovewell ◽  
Yash R. Patankar ◽  
Brent Berwin
Keyword(s):  
Molecular Mechanisms ◽  
Bacterial Pathogen ◽  
Chronic Obstructive ◽  
Flagellar Motility ◽  
Obstructive Pulmonary Disease ◽  
Clinical Observations ◽  
High Incidence ◽  
Cellular Recruitment ◽  
Sterilizing Immunity

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for a high incidence of acute and chronic pulmonary infection. These infections are particularly prevalent in patients with chronic obstructive pulmonary disease and cystic fibrosis: much of the morbidity and pathophysiology associated with these diseases is due to a hypersusceptibility to bacterial infection. Innate immunity, primarily through inflammatory cytokine production, cellular recruitment, and phagocytic clearance by neutrophils and macrophages, is the key to endogenous control of P. aeruginosa infection. In this review, we highlight recent advances toward understanding the innate immune response to P. aeruginosa, with a focus on the role of phagocytes in control of P. aeruginosa infection. Specifically, we summarize the cellular and molecular mechanisms of phagocytic recognition and uptake of P. aeruginosa, and how current animal models of P. aeruginosa infection reflect clinical observations in the context of phagocytic clearance of the bacteria. Several notable phenotypic changes to the bacteria are consistently observed during chronic pulmonary infections, including changes to mucoidy and flagellar motility, that likely enable or reflect their ability to persist. These traits are likewise examined in the context of how the bacteria avoid phagocytic clearance, inflammation, and sterilizing immunity.

scholarly journals Multidrug Resistance in Mammals and Fungi—From MDR to PDR: A Rocky Road from Atomic Structures to Transport Mechanisms

2021 ◽  
Vol 22 (9) ◽  
pp. 4806
Author(s):  
Narakorn Khunweeraphong ◽  
Karl Kuchler
Keyword(s):  
Multidrug Resistance ◽  
High Resolution ◽  
Fungal Pathogens ◽  
Molecular Mechanisms ◽  
Transport Systems ◽  
Parasitic Infections ◽  
New Era ◽  
X Ray Crystallography ◽  
Atomic Structures ◽  
Catalytic Cycles

Multidrug resistance (MDR) can be a serious complication for the treatment of cancer as well as for microbial and parasitic infections. Dysregulated overexpression of several members of the ATP-binding cassette transporter families have been intimately linked to MDR phenomena. Three paradigm ABC transporter members, ABCB1 (P-gp), ABCC1 (MRP1) and ABCG2 (BCRP) appear to act as brothers in arms in promoting or causing MDR in a variety of therapeutic cancer settings. However, their molecular mechanisms of action, the basis for their broad and overlapping substrate selectivity, remains ill-posed. The rapidly increasing numbers of high-resolution atomic structures from X-ray crystallography or cryo-EM of mammalian ABC multidrug transporters initiated a new era towards a better understanding of structure–function relationships, and for the dynamics and mechanisms driving their transport cycles. In addition, the atomic structures offered new evolutionary perspectives in cases where transport systems have been structurally conserved from bacteria to humans, including the pleiotropic drug resistance (PDR) family in fungal pathogens for which high resolution structures are as yet unavailable. In this review, we will focus the discussion on comparative mechanisms of mammalian ABCG and fungal PDR transporters, owing to their close evolutionary relationships. In fact, the atomic structures of ABCG2 offer excellent models for a better understanding of fungal PDR transporters. Based on comparative structural models of ABCG transporters and fungal PDRs, we propose closely related or even conserved catalytic cycles, thus offering new therapeutic perspectives for preventing MDR in infectious disease settings.

scholarly journals A Serine Residue in ClC-3 Links Phosphorylation–Dephosphorylation to Chloride Channel Regulation by Cell Volume

1999 ◽  
Vol 113 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Dayue Duan ◽  
Suzanne Cowley ◽  
Burton Horowitz ◽  
Joseph R. Hume
Keyword(s):  
Cell Volume ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Phosphorylation Site ◽  
Cardiac Cells ◽  
Site Directed Mutagenesis ◽  
Cell Swelling ◽  
Transport Systems ◽  
Serine Residue ◽  
Channel Regulation

In many mammalian cells, ClC-3 volume-regulated chloride channels maintain a variety of normal cellular functions during osmotic perturbation. The molecular mechanisms of channel regulation by cell volume, however, are unknown. Since a number of recent studies point to the involvement of protein phosphorylation/dephosphorylation in the control of volume-regulated ionic transport systems, we studied the relationship between channel phosphorylation and volume regulation of ClC-3 channels using site-directed mutagenesis and patch-clamp techniques. In native cardiac cells and when overexpressed in NIH/3T3 cells, ClC-3 channels were opened by cell swelling or inhibition of endogenous PKC, but closed by PKC activation, phosphatase inhibition, or elevation of intracellular Ca2+. Site-specific mutational studies indicate that a serine residue (serine51) within a consensus PKC-phosphorylation site in the intracellular amino terminus of the ClC-3 channel protein represents an important volume sensor of the channel. These results provide direct molecular and pharmacological evidence indicating that channel phosphorylation/dephosphorylation plays a crucial role in the regulation of volume sensitivity of recombinant ClC-3 channels and their native counterpart, ICl.vol.

scholarly journals The signs of adaptive mutations identified in the chloroplast genome of the algae endosymbiont of Baikal sponge.

F1000Research ◽  
2020 ◽  
Vol 7 ◽  
pp. 1405
Author(s):  
Sergey Feranchuk ◽  
Natalia Belkova ◽  
Lubov Chernogor ◽  
Ulyana Potapova ◽  
Sergei Belikov
Keyword(s):  
Chloroplast Genome ◽  
Molecular Mechanisms ◽  
Ecosystem Dynamics ◽  
Metagenomic Sequencing ◽  
Sequencing Data ◽  
Adaptive Mutations ◽  
Symbiotic Algae ◽  
Unicellular Algae ◽  
Sponge Disease ◽  
Adaptation Processes

Background: Monitoring and investigating the ecosystem of the great lakes provide a thorough background when forecasting the ecosystem dynamics at a greater scale. Nowadays, changes in the Baikal lake biota require a deeper investigation of their molecular mechanisms. Understanding these mechanisms is especially important, as the endemic Baikal sponge disease may cause a degradation of the littoral ecosystem of the lake. Methods: The chloroplast genome fragment for the algae endosymbiont of the Baikal sponge was assembled from metagenomic sequencing data. The distributions of the polymorphic sites were obtained separately for the genome fragments from healthy, diseased and dead sponge tissues. Results: The distribution of polymorphic sites allows for the detection of the signs of extensive mutations in the chloroplasts isolated from the diseased sponge tissues. Additionally, the comparative analysis of chloroplast genome sequences suggests that the symbiotic algae from Baikal sponge is close to the Choricystis genus of unicellular algae. Conclusions: Mutations observed in the chloroplast genome could be interpreted as signs of rapid adaptation processes in the symbiotic algae. The development of sponge disease is still expanding in Baikal, but an optimistic prognoses regarding a development of the disease is nevertheless considered.

scholarly journals Impact of Drifts Resulting from Pesticide Application on Soil Microorganisms around Waste Receptacles in Port Harcourt City, Nigeria

2020 ◽  
pp. 1-8
Author(s):  
D. Momoh ◽  
C. L. Eze ◽  
D. N. Ogbonna
Keyword(s):  
Soil Microorganisms ◽  
Heterotrophic Bacteria ◽  
Soil Depth ◽  
Toxic Substance ◽  
Soil Health ◽  
Mean Value ◽  
Physiological Status ◽  
Pesticide Application ◽  
Port Harcourt ◽  
The Impact

Pesticides are toxic substance used to reduce or kill pests but the deposits on soil environment can remain there for long period of time causing adverse effects on soil microorganisms which are responsible for soil health conditions. This study was carried out to determine the impact of pesticide drifts on soil microorganisms in a waste receptacle around Port Harcourt city. Soil samples were obtained from various depths around waste receptacles with hand auger using standard analytical procedures. Microbial analysis was done according to prescribed standard methods. Characterization and identification of the isolates were based on their cultural, morphological, and cellular characteristics. Results obtained showed that the bacterial isolates were identified as Staphylococus aureus, Bacillus subtilis, Bacillus megaterium, Pseudomonas sp and Micrococcus sp while fungal isolates include Aspergillus niger, Penicillium sp, Fusarium siculi, and Aspergillus fumigatus, Aspergillus nidulas, Microsporium canis and Yeast. The results of the microbial counts revealed that Total Heterotrophic Bacteria (THB) had 2.08 ×109 cfu/g at a depth of 30-45 cm while Total Heterotrophic Fungi (THF) had 6.0×106 cfu/g before application with a mean value of 1.02×109   and    2.8 × 106 cfu/g respectively while after application THB had 4.1 × 108 and 4.6 × 108 cfu/g for 0-15 and 30-45 cm respectively while the THF recorded 1.0 × 106 and 0.6 × 106 cfu/g for 0-15 cm and 30-45 cm respectively. However there was a drastic decrease in the number of microbes in the soils after pesticide application especially at the surface soil depth of 0-15 cm. This shows that the pesticides application affected microbial population by reducing their numbers in the soil and this may in turn affect soil health and physiological status of their habitat. It is therefore recommended that proper surveillance during pesticide application should be considered to avoid drift to non-target organisms and that concentrations of pesticides to be used should be taken into account to avoid reduction in the number of microorganisms in soils because of the vital roles they play in maintaining soil health.

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