scholarly journals Dynamics of chromosome replication and its relationship to predatory attack lifestyles in Bdellovibrio bacteriovorus

2019 ◽  
Author(s):  
Łukasz Makowski ◽  
Damian Trojanowski ◽  
Rob Till ◽  
Carey Lambert ◽  
Rebecca Lowry ◽  
...  
Keyword(s):  
Life Cycle ◽  
Bacterial Infections ◽  
Single Cells ◽  
Chromosome Replication ◽  
Free Living ◽  
Bdellovibrio Bacteriovorus ◽  
Reproductive Phase ◽  
Attack Phase ◽  
Two Phases ◽  
First Time

AbstractBdellovibrio bacteriovorus is a small Gram-negative, an obligate predatory bacterium that is largely found in wet, aerobic environments (i.e. soil). This bacterium attacks and invades other Gram-negative bacteria, including animal and plant pathogens. The intriguing life cycle of B. bacteriovorus consists of two phases: a free-living non-replicative attack phase wherein the predatory bacterium searches for its prey, and a reproductive phase, in which B. bacteriovorus degrades a host’s macromolecules and reuses them for its own growth and chromosome replication. Although the cell biology of this predatory bacterium has gained considerable interest in recent years, we know almost nothing about the dynamics of chromosome replication in B. bacteriovorus. Here, we performed a real-time investigation into the subcellular localization of the replisome(s) in single cells of B. bacteriovorus. Our results confirm that in B. bacteriovorus chromosome replication fires only during the reproductive phase, and show for the first time that this predatory bacterium exhibits a novel spatiotemporal arrangement of chromosome replication. The replication process starts at the invasive pole of the predatory bacterium inside the prey cell and proceeds until several copies of the chromosome have been completely synthesized. This chromosome replication is not coincident with the predator-cell division, and it terminates shortly before synchronous predator-filament septation occurs. In addition, we demonstrate that if this lifecycle fails in some cells of B. bacteriovorus, they can instead use two prey cells sequentially to complete their life cycle.ImportanceNew strategies are needed to combat multidrug-resistant bacterial infections. Application of the predatory bacterium, Bdellovibrio bacteriovorus, which kills other bacteria including pathogens, is considered promising for bacterial infections. The B. bacteriovorus life cycle consists of two phases, a free-living, invasive attack phase and an intracellular reproductive phase, in which this predatory bacterium degrades the host’s macromolecules and reuses them for its own growth. To understand the use of B. bacteriovorus as a ‘living antibiotic’, it is first necessary to dissect its life cycle including chromosome replication. Here, we present for the first time a real-time investigation into subcellular localization of chromosome replication in a single cells of B. bacteriovorus. This process initiates at the invasion pole of B. bacteriovorus and proceeds until several copies of the chromosome have been completely synthesized. Interestingly, we demonstrate that some cells of B. bacteriovorus require two prey cells sequentially to complete their life cycle.

scholarly journals Dynamics of Chromosome Replication and Its Relationship to Predatory Attack Lifestyles inBdellovibrio bacteriovorus

2019 ◽  
Vol 85 (14) ◽  
Author(s):  
Łukasz Makowski ◽  
Damian Trojanowski ◽  
Rob Till ◽  
Carey Lambert ◽  
Rebecca Lowry ◽  
...  
Keyword(s):  
Life Cycle ◽  
Subcellular Localization ◽  
Bacterial Infections ◽  
Chromosome Replication ◽  
Free Living ◽  
Gram Negative ◽  
Content Type ◽  
Reproductive Phase ◽  
Attack Phase ◽  
Two Phases

ABSTRACTBdellovibrio bacteriovorusis a small Gram-negative, obligate predatory bacterium that is largely found in wet, aerobic environments (e.g., soil). This bacterium attacks and invades other Gram-negative bacteria, including animal and plant pathogens. The intriguing life cycle ofB. bacteriovorusconsists of two phases: a free-living nonreplicative attack phase, in which the predatory bacterium searches for its prey, and a reproductive phase, in whichB. bacteriovorusdegrades a host’s macromolecules and reuses them for its own growth and chromosome replication. Although the cell biology of this predatory bacterium has gained considerable interest in recent years, we know almost nothing about the dynamics of its chromosome replication. Here, we performed a real-time investigation into the subcellular localization of the replisome(s) in single cells ofB. bacteriovorus. Our results show that inB. bacteriovorus, chromosome replication takes place only during the reproductive phase and exhibits a novel spatiotemporal arrangement of replisomes. The replication process starts at the invasive pole of the predatory bacterium inside the prey cell and proceeds until several copies of the chromosome have been completely synthesized. Chromosome replication is not coincident with the predator cell division, and it terminates shortly before synchronous predator filament septation occurs. In addition, we demonstrate that if thisB. bacteriovoruslife cycle fails in some cells ofEscherichia coli, they can instead use second prey cells to complete their life cycle.IMPORTANCENew strategies are needed to combat multidrug-resistant bacterial infections. Application of the predatory bacteriumBdellovibrio bacteriovorus, which kills other bacteria, including pathogens, is considered promising for combating bacterial infections. TheB. bacteriovoruslife cycle consists of two phases, a free-living, invasive attack phase and an intracellular reproductive phase, in which this predatory bacterium degrades the host’s macromolecules and reuses them for its own growth. To understand the use ofB. bacteriovorusas a “living antibiotic,” it is first necessary to dissect its life cycle, including chromosome replication. Here, we present a real-time investigation into subcellular localization of chromosome replication in a single cell ofB. bacteriovorus. This process initiates at the invasion pole ofB. bacteriovorusand proceeds until several copies of the chromosome have been completely synthesized. Interestingly, we demonstrate that some cells ofB. bacteriovorusrequire two prey cells sequentially to complete their life cycle.

scholarly journals Microbe Profile: Bdellovibrio bacteriovorus: a specialized bacterial predator of bacteria

Microbiology ◽  
2021 ◽  
Vol 167 (4) ◽  
Author(s):  
Andrew L. Lovering ◽  
R. Elizabeth Sockett
Keyword(s):  
Type Species ◽  
Free Living ◽  
Prey Cell ◽  
Bdellovibrio Bacteriovorus ◽  
Content Type ◽  
Link Type ◽  
Attack Phase ◽  
Future Potential ◽  
Basic Biology ◽  
The Way

Bdellovibrio bacteriovorus is an environmentally-ubiquitous bacterium that uses unique adaptations to kill other bacteria. The best-characterized strain, HD100, has a multistage lifestyle, with both a free-living attack phase and an intraperiplasmic growth and division phase inside the prey cell. Advances in understanding the basic biology and regulation of predation processes are paving the way for future potential therapeutic and bioremediation applications of this unusual bacterium.

scholarly journals Life cycle of predatory bacterium Bdellovibrio bacteriovorus

2018 ◽  
Vol 72 ◽  
pp. 381-391
Author(s):  
Łukasz Makowski ◽  
Jolanta Zakrzewska-Czerwińska
Keyword(s):  
Life Cycle ◽  
Host Cell ◽  
Hydrolytic Enzymes ◽  
Reaction Products ◽  
Bdellovibrio Bacteriovorus ◽  
Diverse Range ◽  
Gram Negative ◽  
Cell Structures ◽  
Large Genome Size ◽  
Attack Phase

Bdellovibrio bacteriovorus is small (0.2 to 0.5 μm wide and 0.5 to 2.5 μm long) Gram-negative bacterium with the distinguishing feature of killing other Gram-negative bacteria including pathogens such as Salmonella Typhimurium, Pseudomonas aeruginosa or Helicobacter pylori. Considering its small cell size, B. bacteriovorus possesses a relatively large genome size (3.8 Mb). The genome encodes a diverse range of hydrolases and proteases (approx. 150) that are involved in killing and digesting the prey. B. bacteriovorus exhibits a biphasic lifestyle: in the free-living attack phase this highly motile bacterium encounters prey and enters to the cell periplasm; in the growth phase B. bacteriovorus degrades the host’s macromolecules using different types of hydrolytic enzymes and uses reaction products to form its own cell structures. When the resources of the host cell are exhausted, the elongated filament synchronously septates to form usually three to six B. bacteriovorus progeny cells. These progeny cells become motile, and then are released into the environment through lysis of the remaining dead host cell. This life cycle takes usually 3-4 hours. Since B. bacteriovorus kills pathogens, it is seen as a living antibiotic, which may provide an alternative to existing antibacterial agents.

scholarly journals Bdellovibrio bacteriovorus phosphoglucose isomerase structures reveal novel rigidity in the active site of a selected subset of enzymes upon substrate binding

Open Biology ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 210098
Author(s):  
R. W. Meek ◽  
I. T. Cadby ◽  
A. L. Lovering
Keyword(s):  
Life Cycle ◽  
Active Site ◽  
Phosphoglucose Isomerase ◽  
Complex Life Cycle ◽  
Induced Fit ◽  
Bdellovibrio Bacteriovorus ◽  
Metabolic States ◽  
Domains Of Life ◽  
Attack Phase ◽  
Selected Subset

Glycolysis and gluconeogenesis are central pathways of metabolism across all domains of life. A prominent enzyme in these pathways is phosphoglucose isomerase (PGI), which mediates the interconversion of glucose-6-phosphate and fructose-6-phosphate. The predatory bacterium Bdellovibrio bacteriovorus leads a complex life cycle, switching between intraperiplasmic replicative and extracellular ‘hunter’ attack-phase stages. Passage through this complex life cycle involves different metabolic states. Here we present the unliganded and substrate-bound structures of the B. bacteriovorus PGI, solved to 1.74 Å and 1.67 Å, respectively. These structures reveal that an induced-fit conformational change within the active site is not a prerequisite for the binding of substrates in some PGIs. Crucially, we suggest a phenylalanine residue, conserved across most PGI enzymes but substituted for glycine in B. bacteriovorus and other select organisms, is central to the induced-fit mode of substrate recognition for PGIs. This enzyme also represents the smallest conventional PGI characterized to date and probably represents the minimal requirements for a functional PGI.

Life Cycle Development of Successful Women-owned Enterprises

2020 ◽  
Vol 3 (4) ◽  
pp. 142-152
Author(s):  
Mohammad Waliul Hasanat ◽  
Kamna Anum ◽  
Ashikul Hoque ◽  
Mahmud Hamid ◽  
Sandy Francis Peris ◽  
...  
Keyword(s):  
Life Cycle ◽  
Data Collection ◽  
Research Work ◽  
Primary Data ◽  
Small Scale ◽  
Data Collection Process ◽  
Theoretical Finding ◽  
Successful Women ◽  
Two Phases ◽  
Life Cycle Development

In developing countries, the role of women in the business sector is continuously improving. As a result, female enterprises have also been encouraged in Pakistan. This study is based on life cycle development phases from which women-owned enterprises have to go through in order to become successful. As a primary data source, face-to-face interviews with owners of successful women-owned enterprises were preferred. The data collection process was divided into two phases i.e. Phase-I and Phase-II. After data collection, qualitative analysis has been performed using NVIVO. Findings provide both generic and specific factors involved in life cycle development of women-owned enterprises. This study provides a detailed view of life cycle development model followed by successful women enterprises. The outcome of this research work is a theoretical finding which can be utilized by entrepreneurs owning small scale enterprises to improve their level of performance. Findings can also be helpful for potentially talented women interested in setting up their own business.

scholarly journals The antimicrobial potential of cannabidiol

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mark A. T. Blaskovich ◽  
Angela M. Kavanagh ◽  
Alysha G. Elliott ◽  
Bing Zhang ◽  
Soumya Ramu ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Modern Medicine ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
New Class ◽  
Clostridioides Difficile ◽  
Excellent Activity ◽  
Induce Resistance ◽  
First Time

AbstractAntimicrobial resistance threatens the viability of modern medicine, which is largely dependent on the successful prevention and treatment of bacterial infections. Unfortunately, there are few new therapeutics in the clinical pipeline, particularly for Gram-negative bacteria. We now present a detailed evaluation of the antimicrobial activity of cannabidiol, the main non-psychoactive component of cannabis. We confirm previous reports of Gram-positive activity and expand the breadth of pathogens tested, including highly resistant Staphylococcus aureus, Streptococcus pneumoniae, and Clostridioides difficile. Our results demonstrate that cannabidiol has excellent activity against biofilms, little propensity to induce resistance, and topical in vivo efficacy. Multiple mode-of-action studies point to membrane disruption as cannabidiol’s primary mechanism. More importantly, we now report for the first time that cannabidiol can selectively kill a subset of Gram-negative bacteria that includes the ‘urgent threat’ pathogen Neisseria gonorrhoeae. Structure-activity relationship studies demonstrate the potential to advance cannabidiol analogs as a much-needed new class of antibiotics.

scholarly journals First Report of Echinococcus ortleppi in Free-Living Wild Boar (Sus scrofa) from Portugal

2021 ◽  
Vol 9 (6) ◽  
pp. 1256
Author(s):  
Teresa Letra Mateus ◽  
Maria João Gargaté ◽  
Anabela Vilares ◽  
Idalina Ferreira ◽  
Manuela Rodrigues ◽  
...  
Keyword(s):  
Wild Boar ◽  
Internal Transcribed Spacer ◽  
Sus Scrofa ◽  
One Health ◽  
Control Strategies ◽  
Free Living ◽  
First Report ◽  
Wildlife Reservoirs ◽  
First Time ◽  
Echinococcus Granulosus Sensu Lato

Cystic echinococcosis (CE) is a zoonosis that is prevalent worldwide. It is considered endemic in Portugal but few studies have been performed on Echinococcus granulosus sensu lato and their hosts. In this study, CE cysts are reported for the first time in a free-living wild boar (Sus scrofa) in Portugal. The presence of the metacestodes in the liver of the wild boar was identified by morphological features, microscopic examination and molecular analysis. The sequencing of part of the DNA nuclear ribosomal internal transcribed spacer-1 (ITS-1) region revealed a G5 genotype that presently corresponds to Echinococcus ortleppi. This is the first report of E. ortleppi in Portugal and to the best of the authors’ knowledge, in Europe. These results suggest that wild boar may be a host of CE, namely, crossing the livestock–wildlife interface, which has important public health implications. Wildlife reservoirs must be taken into account as CE hosts and surveillance of game as well as health education for hunters should be implemented using a One Health approach, with implementation of feasible and tailor-made control strategies, namely, proper elimination of byproducts in the field.

Research of Graphic User Interface of Carbon Dioxide Emission Evaluation Model in Construction Life Cycle Based on Matlab

2013 ◽  
Vol 689 ◽  
pp. 546-550
Author(s):  
Xue Hong Gan ◽  
Wei Wang ◽  
Shi Mei Liu
Keyword(s):  
Carbon Dioxide ◽  
Life Cycle ◽  
Evaluation Model ◽  
Carbon Dioxide Emission ◽  
Graphic User Interface ◽  
Property Management ◽  
Low Carbon ◽  
Management Responsibility ◽  
Residential Quarter ◽  
First Time

To build carbon dioxide emission evaluation model in construction life cycle is the key link to make low-carbon research of theoretical studies head towards practical application. For the first time, residential quarter is selected as the object in the study, carbon dioxide emission management responsibility of owner and property being considered and carbon dioxide emission evaluation model in construction life cycle based on matlab as well as database of carbon dioxide factor being built initially. Net carbon dioxide emission information will be shown timely, then carbon dioxide emission and absorption can be adjusted by property management accordingly.

scholarly journals Differential effects of gram-positive and gram-negative bacterial products on morphine induced inhibition of phagocytosis

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jana Ninkovic ◽  
Vidhu Anand ◽  
Raini Dutta ◽  
Li Zhang ◽  
Anuj Saluja ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Drug Abusers ◽  
Bacterial Clearance ◽  
Chronic Morphine ◽  
Gram Positive ◽  
Bacterial Killing ◽  
Differential Effects ◽  
Secondary Infections ◽  
First Time ◽  
Dependent Signaling Pathway

Abstract Opioid drug abusers have a greater susceptibility to gram positive (Gram (+)) bacterial infections. However, the mechanism underlying opioid modulation of Gram (+) versus Gram (−) bacterial clearance has not been investigated. In this study, we show that opioid treatment resulted in reduced phagocytosis of Gram (+), when compared to Gram (−) bacteria. We further established that LPS priming of chronic morphine treated macrophages leads to potentiated phagocytosis and killing of both Gram (+) and Gram (−) bacteria in a P-38 MAP kinase dependent signaling pathway. In contrast, LTA priming lead to inhibition of both phagocytosis and bacterial killing. This study demonstrates for the first time the differential effects of TLR4 and TLR2 agonists on morphine induced inhibition of phagocytosis. Our results suggest that the incidence and severity of secondary infections with Gram (+) bacteria would be higher in opioid abusers.

scholarly journals Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1203-1215 ◽  
Author(s):  
VICTORIA GILLAN ◽  
EILEEN DEVANEY
Keyword(s):  
Life Cycle ◽  
Heat Shock Protein 90 ◽  
Ecological Niches ◽  
Actual Number ◽  
Host Organism ◽  
Free Living ◽  
Parasitic Species ◽  
Free Living Nematode ◽  
Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

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