scholarly journals Plasmid segregation: spatial awareness at the molecular level

2007 ◽  
Vol 179 (5) ◽  
pp. 813-815 ◽  
Author(s):  
Jakob Møller-Jensen ◽  
Kenn Gerdes
Keyword(s):  
Molecular Level ◽  
Time Lapse ◽  
Spatial Awareness ◽  
Division Plane ◽  
Plasmid Partition ◽  
Plasmid Segregation ◽  
Low Copy Number ◽  
Coli Plasmid ◽  
Cell Division Plane ◽  
Insight Into

In bacteria, low-copy number plasmids ensure their stable inheritance by partition loci (par), which actively distribute plasmid replicates to each side of the cell division plane. Using time-lapse fluorescence microscopic tracking of segregating plasmid molecules, a new study provides novel insight into the workings of the par system from Escherichia coli plasmid R1. Despite its relative simplicity, the plasmid partition spindle shares characteristics with the mitotic machinery of eukaryotic cells.

scholarly journals Prevalence and Significance of Plasmid Maintenance Functions in the Virulence Plasmids of Pathogenic Bacteria

2011 ◽  
Vol 79 (7) ◽  
pp. 2502-2509 ◽  
Author(s):  
Manjistha Sengupta ◽  
Stuart Austin
Keyword(s):  
Copy Number ◽  
Drug Targets ◽  
Pathogenic Bacteria ◽  
Plasmid Copy ◽  
Plasmid Partition ◽  
Plasmid Segregation ◽  
Daughter Cells ◽  
Virulence Plasmids ◽  
Low Copy Number ◽  
Stable Maintenance

ABSTRACTVirulence functions of pathogenic bacteria are often encoded on large extrachromosomal plasmids. These plasmids are maintained at low copy number to reduce the metabolic burden on their host. Low-copy-number plasmids risk loss during cell division. This is countered by plasmid-encoded systems that ensure that each cell receives at least one plasmid copy. Plasmid replication and recombination can produce plasmid multimers that hinder plasmid segregation. These are removed by multimer resolution systems. Equitable distribution of the resulting monomers to daughter cells is ensured by plasmid partition systems that actively segregate plasmid copies to daughter cells in a process akin to mitosis in higher organisms. Any plasmid-free cells that still arise due to occasional failures of replication, multimer resolution, or partition are eliminated by plasmid-encoded postsegregational killing systems. Here we argue that all of these three systems are essential for the stable maintenance of large low-copy-number plasmids. Thus, they should be found on all large virulence plasmids. Where available, well-annotated sequences of virulence plasmids confirm this. Indeed, virulence plasmids often appear to contain more than one example conforming to each of the three system classes. Since these systems are essential for virulence, they can be regarded as ubiquitous virulence factors. As such, they should be informative in the search for new antibacterial agents and drug targets.

scholarly journals Noni fruit’s water spot appearance on the second day of harvest: a trade-off between resistance and energy

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tian Wu ◽  
Danyan Hu ◽  
Qingfen Wang
Keyword(s):  
Statistical Analysis ◽  
Molecular Level ◽  
Morinda Citrifolia ◽  
Transcriptome Data ◽  
Trade Off ◽  
Kegg Pathways ◽  
Available Energy ◽  
Climacteric Fruit ◽  
The Relationship ◽  
Insight Into

Abstract Background Noni (Morinda citrifolia Linn.) is a tropical tree that bears climacteric fruit. Previous observations and research have shown that the second day (2 d) after harvest is the most important demarcation point when the fruit has the same appearance as the freshly picked fruit (0 d); however, they are beginning to become water spot appearance. We performed a conjoint analysis of metabolome and transcriptome data for noni fruit of 0 d and 2 d to reveal what happened to the fruit at the molecular level. Genes and metabolites were annotated to KEGG pathways and the co-annotated KEGG pathways were used as a statistical analysis. Results We found 25 pathways that were significantly altered at both metabolic and transcriptional levels, including a total of 285 differentially expressed genes (DEGs) and 11 differential metabolites through an integrative analysis of transcriptomics and metabolomics. The energy metabolism and pathways originating from phenylalanine were disturbed the most. The upregulated resistance metabolites and genes implied the increase of resistance and energy consumption in the postharvest noni fruit. Most genes involved in glycolysis were downregulated, further limiting the available energy. This lack of energy led noni fruit to water spot appearance, a prelude to softening. The metabolites and genes related to the resistance and energy interacted and restricted each other to keep noni fruit seemingly hard within two days after harvest, but actually the softening was already unstoppable. Conclusions This study provides a new insight into the relationship between the metabolites and genes of noni fruit, as well as a foundation for further clarification of the post-ripening mechanism in noni fruit.

scholarly journals Cisplatin under oriented external electric fields: A deeper insight into electrochemotherapy at the molecular level

2020 ◽  
Author(s):  
Li Zhang ◽  
Ya‐Ling Ye ◽  
Xiao‐Ling Zhang ◽  
Xiang‐Hui Li ◽  
Qiao‐Hong Chen ◽  
...  
Keyword(s):  
Electric Fields ◽  
Molecular Level ◽  
External Electric Fields ◽  
Insight Into

scholarly journals Molecular-Level Insight into How Hydroxyl Groups Boost Catalytic Activity in CO2 Hydrogenation into Methanol

Chem ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 613-625 ◽  
Author(s):  
Yuhan Peng ◽  
Liangbing Wang ◽  
Qiquan Luo ◽  
Yun Cao ◽  
Yizhou Dai ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molecular Level ◽  
Co2 Hydrogenation ◽  
Hydroxyl Groups ◽  
Insight Into

scholarly journals Insight into molecular-level interactions between imidazolium-based ionic liquids and cellulose combining NMR, SAXS and MD simulations

2019 ◽  
Vol 75 (a1) ◽  
pp. a268-a268
Author(s):  
Aparna Annamraju ◽  
Nicholas D. Smith ◽  
Loukas Petridis ◽  
Hugh O'Neill ◽  
Sai Venkatesh Pingali ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Molecular Level ◽  
Md Simulations ◽  
Insight Into

scholarly journals HARBOR STUDY FOR SAN NICOLAS BAY, PERU

1970 ◽  
Vol 1 (12) ◽  
pp. 133
Author(s):  
James M. Keith ◽  
Emmett J. Murphy
Keyword(s):  
Particle Velocity ◽  
Time Lapse ◽  
Wave Action ◽  
Ship Motion ◽  
Long Period ◽  
Wave Property ◽  
Directional Wave ◽  
Detailed Interpretation ◽  
Wave Phenomena ◽  
Insight Into

A pair of ducted impeller current meters, one mounted vertically and the other horizontally, were used to measure wave action at San Nicolas Harbor, Peru The horizontal water velocity records are superior to conventional wave records because they measure directly the wave property which induces adverse horizontal ship motion, and provide directional wave data Spectral analysis methods proved well-suited to detailed interpretation of the particle velocity records, while considerable insight into the wave phenomena was gained by simple, rational inspections and interpretations of the records Time-lapse movies of a moored ship, when correlated with simultaneous water particle velocity records, provided an exceptionally clear picture of ship response to wave action, and led to the rather surprising observation that long-period ship motion is not necessarily caused by long-period waves The foregoing ship response was duplicated in hydrau1ic model tests.

scholarly journals A family of T6SS antibacterial effectors related to L,D-transpeptidases targets the Peptidoglycan

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Stephanie Sibinelli de Sousa ◽  
Julia Takuno Hespanhol ◽  
Bruno Matsuyama ◽  
Stephane Mesnage ◽  
Gianlucca Nicastro ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Point Mutations ◽  
Time Lapse ◽  
Secretion Systems ◽  
Bacterial Antagonism ◽  
New Family ◽  
Type Vi Secretion ◽  
Altered Cell ◽  
Bacterial Effectors ◽  
Insight Into

Type VI secretion systems (T6SSs) are contractile nanomachines widely used by bacteria to intoxicate competitors. Salmonella Typhimurium encodes a T6SS within the Salmonella pathogenicity island 6 (SPI-6) that is used during competition against species of the gut microbiota. We characterized a new SPI-6 T6SS antibacterial effector named Tlde1 (type VI L,D-transpeptidase effector 1). Tlde1 is toxic in target-cell periplasm and its toxicity is neutralized by co-expression with immunity protein Tldi1 (type VI L,D-transpeptidase immunity 1). Time-lapse microscopy revealed that intoxicated cells display altered cell division and lose cell envelope integrity. Bioinformatics analysis showed that Tlde1 is evolutionarily related to L,D-transpeptidases. Point mutations on conserved histidine121 and cysteine131 residues eliminated toxicity. Co-incubation of purified recombinant Tlde1 and peptidoglycan tetrapeptides showed that Tlde1 displays both L,D-carboxypeptidase activity by cleaving GM-tetrapeptides between meso-diaminopimelic acid3 and D-alanine4, and L,D-transpeptidase exchange activity by replacing D-alanine4 for a non-canonical D-amino acid. Tlde1 constitutes a new family of T6SS effectors widespread in Proteobacteria. This work increases our knowledge about the bacterial effectors used in interbacterial competitions and provides molecular insight into a new mechanism of bacterial antagonism.

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