Chronic oral infection with the periodontal disease pathogen, Porphyromonas gingivalis, not only causes local inflammation of the gums leading to tooth loss but also is associated with an increased risk of atherosclerosis. A study published on July 10th in PLOS Pathogens now reveals how the pathogen evades the immune system to induce inflammation beyond the oral cavity.
Like other gram-negative bacteria, P. gingivalis has an outer layer that consists of sugars and lipids. The mammalian immune system has evolved to recognize parts of this bacterial coating, which then triggers a multi-pronged immune reaction. As part of the “arms race” between pathogens and their hosts, several types of gram-negative bacteria, including P. gingivalis, employ strategies by which they alter their outer coats to avoid the host immune defense.
Caroline Attardo Genco, from Boston University School of Medicine, USA, in collaboration with Richard Darveau, at the University of Washington School of Dentistry, USA, and colleagues focused on the role of a specific lipid expressed on the outer surface of P. gingivalis, called lipid A, which is known to interact with a key regulator of the host’s immune system called TLR4. P. gingivalis can produce a number of different lipid A versions, and the researchers wanted to clarify how these modify the immune response and contribute to the ability of the pathogen to survive and cause inflammation—both locally, resulting in oral bone loss, and systemically, in distant blood vessels. Read more…
Mosquitoes infected with the bacteria Wolbachia are more likely to become infected with West Nile virus and more likely to transmit the virus to humans, according to a team of researchers.
PLOS Neglected Tropical Diseases
“Previous research has shown that Wolbachia — a genus of bacteria that live inside mosquitoes — render mosquitoes resistant to pathogen infection, thereby preventing the mosquitoes from infecting humans with the pathogens,” said Jason Rasgon, associate professor of entomology, Penn State. “As a result, researchers are currently releasing Wolbachia-infected mosquitoes into the wild as part of a strategy to control Dengue virus. They also are investigating Wolbachia as a possible control strategy for malaria.”
Expecting to find that Wolbachia would block infection by West Nile virus in the same way that it blocks Dengue virus, Rasgon and his colleagues — which include researchers at the University of Maryland, the New York State Department of Health and the State University of New York at Albany — injected the Wolbachia bacteria into adult female Culex tarsalis mosquitoes. They then allowed the Wolbachia to replicate inside the mosquitoes and fed the mosquitoes a meal of blood that was infected with West Nile virus. Read more…
- Obesity is common among U.S. Hispanics and is severe among young Hispanics.
- This is associated with a considerable risk for heart diseases.
Journal of the American Heart Association (JAHA)
Obesity is common among U.S. Hispanics and is severe particularly among young Hispanics, according to research in the Journal of the American Heart Association (JAHA).
The first large-scale data on body mass index (BMI) and cardiovascular disease risk factors among U.S. Hispanic/Latino adult populations suggests that severe obesity may be associated with considerable excess risk for cardiovascular diseases.
For U.S. Hispanics, the obesity epidemic “is unprecedented and getting worse,” said Robert Kaplan, Ph.D., lead author, and professor of epidemiology and population health at Albert Einstein College of Medicine in New York City. “Because young adults with obesity are likely to be sicker as they age, and have higher healthcare costs, we should be investing heavily in obesity research and prevention, as if our nation’s future depended upon it.” Read more…
Wild gorillas signal using odor.
Silverback gorillas appear to use odor as a form of communication to other gorillas, according to a study published July 9, 2014 in the open-access journal PLOS ONE by Michelle Klailova from University of Stirling, UK, and colleagues.
Mammals communicate socially through visual, auditory, and chemical signals. The chemical sense is in fact the oldest sense, shared by all organisms including bacteria, and mounting evidence suggests that humans also participate in social chemical signaling. However, not much is known about this type of signaling in closely related hominoids, like wild apes. To better understand chemical -communication in apes, scientists in this study analyzed odor strength in relation to arousal levels in a wild group of western lowland gorillas in the Central African Republic, specifically focusing on the male silverback, or the mature leader of the group. Scientists determined the factors that predicted extreme levels of odor emission from the silverback. They hypothesized that if gorilla scent were being used as a social signal, instead of only a sign of arousal or stress, odor emission would depend on social context and would vary depending on the gorilla’s relationship to other gorillas.
According to the results, the male silverback may use odor as a modifiable form of social communication, where context-specific chemical-signals may moderate the social behaviors of other gorillas. The authors predicted extreme silverback odor, where the odor was the only element that could be smelled in the surrounding air, by the presence and intensity of interactions between different gorilla groups such as silverback anger, distress and long-calling auditory rates, and the absence of close proximity between the silverback and the mother of the youngest infant. The authors suggest that odor communication between apes may be especially useful in Central African forests, where limited visibility may necessitate increased reliance on other senses.
Michelle Klailova added, “No study has yet investigated the presence and extent to which chemo–communication may moderate behaviour in non-human great apes. We provide crucial ancestral links to human chemo-signaling, bridge the gap between Old World monkey and human chemo-communication, and offer compelling evidence that olfactory communication in hominoids is much more important than traditionally thought.” Read more…
There are billions of stars and planets in the universe. A star is a glowing sphere of gas, while planets like Earth are made up of solids. The planets are formed in dust clouds that swirled around a newly formed star. Dust grains are composed of elements like carbon, silicon, oxygen, iron, and magnesium. But where does the cosmic dust come from? New research from the Niels Bohr Institute at the University of Copenhagen and Aarhus University shows that not only can grains of dust form in gigantic supernova explosions, they can also survive the subsequent shockwaves they are exposed to. The results are published in the prestigious scientific journal Nature. Read more…