Science Current Events | Science News | Brightsurf.com
 

New mechanism of bacterial pathogenesis discovered

June 28, 2012
Scientists have identified a new mechanism of bacterial pathogenesis. The results of the research project, partly funded by the Academy of Finland, have been published in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

Bacteria that cause chronic infections have an amazing but yet poorly known ability to subvert immune response, live and produce offspring, enter and wake up from a dormant phase to cause, in some instances, deadly complications.

Bartonella bacteria cause chronic infections in mammals (incl. humans), and are typically transmitted to new hosts mainly by arthropod vectors such as fleas, lice and ticks, but also via direct tissue trauma (e.g. cat scratches).

One very notable feature of these bacteria is their ability to cause vasoproliferative tumours that resemble Kaposi's sarcoma in patients suffering from immunodeficiency (e.g. AIDS, aggressive cancer treatments, organ transplantation). If left untreated, these foci of inflammation maintain a chronic infection and contribute to transmitting bacteria to new hosts.

In his research, biologist Arto Pulliainen (University of Turku) has demonstrated that Bartonella henselae injects a protein called BepA into vascular endothelial cells and that this protein manipulates cAMP-mediated cell signalling using a previously unknown mechanism.

BepA directly binds the host cell adenylyl cyclase, which is an enzyme responsible for the production of cAMP. However, the binding of BepA to the adenylyl cyclase does not activate cAMP production per se, but the adenylyl cyclase rather becomes more sensitive to its natural activator, stimulatory G-protein (Gαs). The cellular concentration of cAMP increases and prevents the death of the host cell. BepA significantly prolongs the lifespan of the host cell and partly contributes to the formation of vasoproliferative tumours.

Several bacterial species are known to manipulate host cell functions via cAMP-mediated cell signalling. The symptoms are typically very strong and may even be deadly. The best-known example is Vibrio cholerae and its cholera toxin, which modifies Gαs into a permanently adenylyl cyclase-stimulating form. BepA, in turn, manipulates host cell signalling in a subtle sophisticated manner, which is ideal for chronic persistence of Bartonella henselae in the infected vascular endothelium.

The research has been carried out at the Universities of Basel and Turku.

Academy of Finland


Related Host Cell Current Events and Host Cell News Articles


Changes in HIV genetic code determine severity of disease
In a finding that furthers the understanding of human immunodeficiency virus (HIV), researchers from Children's Hospital Los Angeles discovered two locations where a single difference in HIV's genetic code altered the way the virus infected the cell, thereby influencing the progression of the disease.

UMN scientists identify 2 mutations critical for MERS transmission from bats to humans
Researchers have identified two critical mutations allowing the deadly Middle East Respiratory Syndrome (MERS) virus to transmit from bats to humans.

Molecular docking site of a bacterial toxin identified
Clostridium difficile is a dangerous intestinal bacterium that can cause severe diarrhoea and life-threatening intestinal infections after long-term treatment with antibiotics.

Study identifies Ebola virus's Achilles' heel
An international team including scientists from Albert Einstein College of Medicine of Yeshiva University and the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) has identified the molecular "lock" that the deadly Ebola virus must pick to gain entry to cells.

Scientists identify crucial step in helping to prevent Hepatitis C virus replicating
New research from the University of Southampton has identified how changes in the cell membrane play a pivotal role in how the Hepatitis C virus replicates.

TSRI scientists identify interferon beta as likely culprit in persistent viral infections
Interferon proteins are normally considered virus-fighters, but scientists at The Scripps Research Institute (TSRI) have found evidence that one of them, interferon beta (IFNβ), has an immune-suppressing effect that can help some viruses establish persistent infections.

Advanced viral gene therapy eradicates prostate cancer in preclinical experiments
Even with the best available treatments, the median survival of patients with metastatic, hormone-refractory prostate cancer is only two to three years.

Bacterial viruses: Tools of the trade
Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich demonstrate for the first time that bacteriophages (bacterial viruses) carry genetic instructions for proteins that mediate the transport of their DNA to specialized replication sites in the host cell.

Bacterial 'memory' targets invading viruses
One of the immune system's most critical challenges is to differentiate between itself and foreign invaders -- and the number of recognized autoimmune diseases, in which the body attacks itself, is on the rise. But humans are not the only organisms contending with "friendly fire."

How Salmonella survives the macrophage's acid attack
Macrophages destroy bacteria by engulfing them in intracellular compartments, which they then acidify to kill or neutralize the bacteria.
More Host Cell Current Events and Host Cell News Articles

HIV Interactions with Host Cell Proteins (Current Topics in Microbiology and Immunology)

HIV Interactions with Host Cell Proteins (Current Topics in Microbiology and Immunology)
by Paul Spearman (Editor), Eric O. Freed (Editor)


The study of viruses necessarily involves dissecting the intimate details of cellular pathways. Viruses have often been employed as tools in studying cellular pathways, as was done by early retrovirologists such as Peyton Rous in attempting to understand the mechanism of cellular transformation and oncogenesis. On the other side of the coin, virologists seek to de?ne those cellular elements interacting intimatelywiththeir virus ofinterestinorder to better understand viral replication itself, and in some cases to develop antiviral strategies. It is in the intersection of virology and cell biology that many of us ?nd the most rewarding aspects of our research. When a new discovery yields insights into basic cellular mechanisms and presents new targets for int- vention to ?ght a serious...

Host Response to Biomaterials: The Impact of Host Response on Biomaterial Selection

Host Response to Biomaterials: The Impact of Host Response on Biomaterial Selection
by Stephen F Badylak (Editor)


Host Response to Biomaterials: The Impact of Host Response on Biomaterial Selection explains the various categories of biomaterials and their significance for clinical applications, focusing on the host response to each biomaterial. It is one of the first books to connect immunology and biomaterials with regard to host response. The text also explores the role of the immune system in host response, and covers the regulatory environment for biomaterials, along with the benefits of synthetic versus natural biomaterials, and the transition from simple to complex biomaterial solutions. Fields covered include, but are not limited to, orthopaedic surgery, dentistry, general surgery, neurosurgery, urology, and regenerative medicine. Explains the various categories of biomaterials and their...

CELLS

CELLS
by Benjamin Lewin (Author), Lynne Cassimeris (Author), Vishwanath R. Lingappa (Author), George Plopper (Author)


This important new textbook, designed for advanced undergraduate and early graduate courses in cell biology, covers the structures, organization, growth, regulation, movements, and interactions of cells, with emphasis on eukaryotic cells. Under the direction of Dr. Benjamin Lewin and three expert section editors, each chapter was prepared by top scientists who specialize in the given subject area, and all chapters have been carefully edited to maintain a consistent level throughout the text and to assure that all necessary topics are covered.

Interaction of Trypanosoma cruzi with Host Cells

Interaction of Trypanosoma cruzi with Host Cells


Trypanosoma cruzi is a pathogenic protozoan of the Trypanosomatidade Family, which is the etiological agent of Chagas’ disease. Chagas’ disease stands out for being endemic among countries in Latin America, affecting about 15 million people. Recently, Chagas has become remarkable in European countries as well due to cases of transmission via infected blood transfusion. An important factor that has exacerbated the epidemiological picture in Brazil, Colombia and Venezuela is infection after the oral intake of contaminated foods such as sugar cane, açai and bacaba juices. Trypanosoma cruzi is an intracellular protozoan that exhibits a complex life cycle, involving multiple developmental stages found in both vertebrate and invertebrate hosts. In vertebrate hosts, the trypomastigote form...

Bacterial Lipopolysaccharides: Structure, Chemical Synthesis, Biogenesis and Interaction with Host Cells

Bacterial Lipopolysaccharides: Structure, Chemical Synthesis, Biogenesis and Interaction with Host Cells
by Yuriy A. Knirel (Editor), Miguel A. Valvano (Editor)


The bacterial lipopolysaccharide also known as endotoxin is exhaustively covered in the present work. Central emphasis is placed upon the fine chemical structure of the lipopolysaccharide and its significance for understanding their activity and function. In particular, the role it plays in the interaction of bacteria with other biological systems is examined. New aspects of their physicochemical biology are introduced and updates to the current knowledge concerning the lipopolysaccharide are provided. This important class of biomolecules has recently attracted the attention of many investigators, in particular for understanding its involvement in innate immunity, toll-like receptor recognition and intracellular signaling.

Intracellular Niches of Microbes: A Microbes Guide Through the Host Cell

Intracellular Niches of Microbes: A Microbes Guide Through the Host Cell
by Ulrich E. Schaible (Editor), Albert Haas (Editor)


The book describes the different and exciting pathways which have been developed by pathogenic microbes to manage living inside host cells. It covers intracellular life styles of all relevant pathogenic but also symbiotic microorganisms with respect to the cell biology of the host-microbe interactions and the microbial adaptations for intracellular survival. It features intracellular trafficking pathways and characteristics of intracellular niches of individual microbes. The book also asks questions on the benefits for the microbe with regard to physiological needs and nutritional aspects such as auxotrophy, effects on genome sizes, and consequences for disease and host response/immunity (and the benefits for the host in the cases of symbionts).

Additionally, the book...

Molecular Biology of the Cell, Fourth Edition

Molecular Biology of the Cell, Fourth Edition
by Bruce Alberts (Author), Alexander Johnson (Author), Julian Lewis (Author), Martin Raff (Author), Keith Roberts (Author), Peter Walter (Author)


Molecular Biology of the Cell is the classic in-dept text reference in cell biology. By extracting the fundamental concepts from this enormous and ever-growing field, the authors tell the story of cell biology, and create a coherent framework through which non-expert readers may approach the subject. Written in clear and concise language, and beautifully illustrated, the book is enjoyable to read, and it provides a clear sense of the excitement of modern biology. Molecular Biology of the Cell sets forth the current understanding of cell biology (completely updated as of Autumn 2001), and it explores the intriguing implications and possibilities of the great deal that remains unknown. The hallmark features of previous editions continue in the Fourth Edition. The book is designed with a...

Cell Biology: With STUDENT CONSULT Access, 2e (Pollard, Cell Biology,  with Student Consult Online Access)

Cell Biology: With STUDENT CONSULT Access, 2e (Pollard, Cell Biology, with Student Consult Online Access)
by Thomas D. Pollard MD (Author), William C. Earnshaw PhD FRSE (Author), Jennifer Lippincott-Schwartz PhD (Author)


A masterful introduction to the cell biology that you need to know! This critically acclaimed textbook offers you a modern and unique approach to the study of cell biology. It emphasizes that cellular structure, function, and dysfunction ultimately result from specific macromolecular interactions. You'll progress from an explanation of the "hardware" of molecules and cells to an understanding of how these structures function in the organism in both healthy and diseased states. The exquisite art program helps you to better visualize molecular structures.Covers essential concepts in a more efficient, reader-friendly manner than most other texts on this subject. Makes cell biology easier to understand by demonstrating how cellular structure, function, and dysfunction result from specific...

Cell Press Reviews: Cancer Therapeutics (Cell Press Reviews Series)

Cell Press Reviews: Cancer Therapeutics (Cell Press Reviews Series)
by Cell Press (Editor)


Cell Press Reviews: Cancer Therapeutics informs, inspires, and connects cancer researchers at all stages in their careers with timely, comprehensive reviews written by leaders in the field and curated by Cell Press editors. The publicatio offers a broad view of some of the most compelling topics in cancer therapeutics including: Genetic approaches for personal oncologyTargeting epigenetic dysregulation and protein interaction networksVaccines and antibodies in cancer immunotherapyTumor heterogeneity and chemotherapy resistanceTumor associated macrophages in anticancer treatment Contributions come from leading voices in the field, including: - Daniel A. Haber, Director of Massachusetts General Hospital Cancer Center and Professor at Harvard Medical School - Tony Kouzarides, Professor at...

Cell Talk: Transmitting Mind into DNA

Cell Talk: Transmitting Mind into DNA
by John E. Upledger (Author)


Craniosacral therapy (CST) has become an important modality in treating trauma and promoting wellness. With its gentle approach to working with the spine, the skull and its cranial sutures, diaphragms, and fascia, CST has proven equally useful for physical therapists, massage therapists, naturopaths, chiropractors, and osteopaths. One reason for its success has been its underlying theory, as explained by CST pioneer John Upledger. According to Upledger, bodily tissues and cells have individual memories, and traumatic memories can be stored in these cells and tissues. Cell Talk, written for the layperson, explores this concept in depth and shows practitioners how to use it in healing their patients.

The book offers simple strategies for treating disease and dysfunction by...

© 2015 BrightSurf.com