scholarly journals The role of flagella in Pseudomonas-Pedobacter social motility across a surface

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Lucy McCully ◽  
Sarah Seaton ◽  
Alana McGraw ◽  
Mark Silby
Keyword(s):  
Bacterial Species ◽  
Soft Agar ◽  
Natural Soil ◽  
Flagellar Motility ◽  
Social Phenotype ◽  
Agar Surface ◽  
Social Motility ◽  
Membrane Spanning ◽  
And Function

Bacteria often reside in multi-species communities where many behaviors result from interspecies relationships. In a two-species community, we show that co-culture of Pseudomonas fluorescens and Pedobacter sp. permits motility across a hard agar surface where neither species moves alone. Pseudomonas species engage in surface motility, including swimming and swarming, but these require moist environments. We are exploring the role of the Pseudomonas flagella in social motility. We deleted genes related to flagellar structure and function to study the importance of flagellar elements on the social phenotype. Using microscopy and swimming assays, we evaluate the effects of gene deletions on the presence and function of flagella in the resulting mutants, and evaluate the effect on social motility by observing the phenotype on both hard (2% w/v) and soft agar (1% w/v). Removal of the flagellar filament abolishes social motility, indicating a requirement for flagella in social motility. Removal of the flagellar motor also abolishes social motility, demonstrating that flagella must be functional. However, removal of membrane-spanning structural components, or part of the type III secretion system, results in mutants that lack flagella, but participate in a similar motile behavior with Pedobacter. Here we describe a role for flagella in motility of a two-species consortium across a hard agar surface, an environment considered non-permissive for flagellar motility. The requirement for both bacterial species indicates we are observing motility as a social phenotype, with a contribution from Pedobacter that enables the Pseudomonas flagella to function under conditions relevant in the natural soil environment.

scholarly journals hfqPlays Important Roles in Virulence and Stress Adaptation in Cronobacter sakazakii ATCC 29544

2015 ◽  
Vol 83 (5) ◽  
pp. 2089-2098 ◽  
Author(s):  
Seongok Kim ◽  
Hyelyeon Hwang ◽  
Kwang-Pyo Kim ◽  
Hyunjin Yoon ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Soft Agar ◽  
Host Cells ◽  
Neonatal Meningitis ◽  
Animal Cells ◽  
Content Type ◽  
Flagellar Biosynthesis

Cronobacterspp. are opportunistic pathogens that cause neonatal meningitis and sepsis with high mortality in neonates. Despite the peril associated withCronobacterinfection, the mechanisms of pathogenesis are still being unraveled. Hfq, which is known as an RNA chaperone, participates in the interaction with bacterial small RNAs (sRNAs) to regulate posttranscriptionally the expression of various genes. Recent studies have demonstrated that Hfq contributes to the pathogenesis of numerous species of bacteria, and its roles are varied between bacterial species. Here, we tried to elucidate the role of Hfq inC. sakazakiivirulence. In the absence ofhfq,C. sakazakiiwas highly attenuated in disseminationin vivo, showed defects in invasion (3-fold) into animal cells and survival (103-fold) within host cells, and exhibited low resistance to hydrogen peroxide (102-fold). Remarkably, the loss ofhfqled to hypermotility on soft agar, which is contrary to what has been observed in other pathogenic bacteria. The hyperflagellated bacteria were likely to be attributable to the increased transcription of genes associated with flagellar biosynthesis in a strain lackinghfq. Together, these data strongly suggest thathfqplays important roles in the virulence ofC. sakazakiiby participating in the regulation of multiple genes.

scholarly journals Distinct Metagenomic Signatures in the SARS-CoV-2 Infection

2021 ◽  
Vol 11 ◽  
Author(s):  
Yijun Liu ◽  
Hongyang Zhang ◽  
Xiaojun Tang ◽  
Xuejun Jiang ◽  
Xiaojuan Yan ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Bacterial Species ◽  
Gastrointestinal Symptoms ◽  
Microbiome Composition ◽  
Key Species ◽  
The Difference ◽  
Genome Annotations ◽  
And Function ◽  
First Time

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause gastrointestinal symptoms in the patients, but the role of gut microbiota in SARS-CoV-2 infection remains unclear. Thus, in this study, we aim to investigate whether SARS-CoV-2 infection affects the composition and function of gut microbiota. In this study, we demonstrated for the first time that significant shifts in microbiome composition and function were appeared in both SARS-CoV-2-infected asymptomatic and symptomatic cases. The relative abundance of Candidatus_Saccharibacteria was significantly increased, whereas the levels of Fibrobacteres was remarkably reduced in SARS-CoV-2-infected cases. There was one bacterial species, Spirochaetes displayed the difference between patients and asymptomatic cases. On the genus level, Tyzzerella was the key species that remarkably increased in both symptomatic and asymptomatic cases. Analyses of genome annotations further revealed SARS-CoV-2 infection resulted in the significant ‘functional dysbiosis’ of gut microbiota, including metabolic pathway, regulatory pathway and biosynthesis of secondary metabolites etc. We also identified potential metagenomic markers to discriminate SARS-CoV-2-infected symptomatic and asymptomatic cases from healthy controls. These findings together suggest gut microbiota is of possible etiological and diagnostic importance for SARS-CoV-2 infection.

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

1999 ◽  
Vol 81 (06) ◽  
pp. 951-956 ◽  
Author(s):  
J. Corral ◽  
R. González-Conejero ◽  
J. Rivera ◽  
F. Ortuño ◽  
P. Aparicio ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cell Types ◽  
Receptor Expression ◽  
Case Control Studies ◽  
Platelet Surface ◽  
Vitro Analysis ◽  
And Function ◽  
In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

Von Willebrand disease and Weibel-Palade bodies

2010 ◽  
Vol 30 (03) ◽  
pp. 150-155 ◽  
Author(s):  
J. W. Wang ◽  
J. Eikenboom
Keyword(s):  
Platelet Adhesion ◽  
Coagulation Factor ◽  
Von Willebrand Disease ◽  
Inflammatory Factors ◽  
Limited Data ◽  
Storage Organelle ◽  
And Function ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryVon Willebrand factor (VWF) is a pivotal haemostatic protein mediating platelet adhesion to injured endothelium and carrying coagulation factor VIII (FVIII) in the circulation to protect it from premature clearance. Apart from the roles in haemostasis, VWF drives the formation of the endothelial cell specific Weibel-Palade bodies (WPBs), which serve as a regulated storage of VWF and other thrombotic and inflammatory factors. Defects in VWF could lead to the bleeding disorder von Willebrand disease (VWD).Extensive studies have shown that several mutations identified in VWD patients cause an intracellular retention of VWF. However, the effects of such mutations on the formation and function of its storage organelle are largely unknown. This review gives an overview on the role of VWF in WPB biogenesis and summarizes the limited data on the WPBs formed by VWD-causing mutant VWF.

Identifikasi Peran dan Strategi Pelabuhan Bebas Sabang

2020 ◽  
Vol 4 (3) ◽  
pp. 167-178
Author(s):  
Zurayna Sari
Keyword(s):  
Economic Development ◽  
Descriptive Analysis ◽  
Regional Growth ◽  
Maintenance Strategy ◽  
Regional Economic ◽  
Growth Center ◽  
Free Port ◽  
And Function ◽  
Role And Function

ABSTRAKPelabuhan berperan sebagai fasilitas penunjang pusat pertumbuhan regional dalam proses pembangunan ekonomi wilayah. Pelabuhan Bebas Sabang diarahkan sebagai pusat pertumbuhan ekonomi regional dan diharapkan dapat meningkatkan perekonomian Kawasan Sabang. Permasalahan yang dihadapi Pelabuhan Bebas Sabang adalah belum optimalnya peran dan fungsi Pelabuhan Bebas Sabang dalam menunjang perekonomian wilayah. Penelitian ini bertujuan untuk mengetahui peran Pelabuhan Bebas Sabang dalam mendorong perkembangan perekonomian Kawasan Sabang. Lingkup materi yang dibahas mencakup peran-peran Pelabuhan Bebas Sabang, menentukan potensi dan masalah serta upaya-upaya peningkatan peran Pelabuhan Bebas Sabang. Metode analisis yang dilakukan adalah analisis deskriptif dengan pendekatan analisis data kualitatif dan kuantitatif. Alat analisis yang digunakan adalah analisis SWOT IFAS-EFAS. Hasil analisis menunjukkan dalam kurun waktu 4 (empat) tahun terakhir dari tahun 2010-2013, Pelabuhan Bebas Sabang belum optimal dalam menjalankan perannya, sehingga membutuhkan strategi pengembangan dengan pendekatan Agressive Maintenance Strategy (strategi perbaikan agresif), yaitu strategi konsolidasi internal dengan memperbaiki faktor-faktor kelemahan untuk memaksimalkan pemanfaatan peluang.Kata kunci: Pengelolaan, SWOT IFAS-EFAS, WilayahABSTRACTPort was supporting facility of regional growth center in the process of regional economic development. Sabang free port was directed as the center of regional economic growth and expected to raise the economy of sabang. Problems faced by sabang free port was yet optimal role and function in supporting the economy of the region. This study aimed to determine the role of sabang free port in supporting the economic development of sabang. The covered material scope included roles of sabang free port, determining the potentials and problems and efforts of increasing the role of sabang free port. The method of analysis was descriptive analysis with qualitative and quantitative approach. The analytical tool used was the swot ifas-efas analysis. The analysis results showed in the period of 4 (four) years from 2010 until 2013, sabang free port was not optimal in carrying out its role yet, so it requires development strategies with agressive maintenance strategy approach, which is internal consolidation strategy by improving vulnerability factors to maximize the utilization of opportunities.Keywords:, Management, Regional, SWOT IFAS-EFAS

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