Ancient Bones Hold TB Clues

A team of Israeli, Palestinian and German scientists is analyzing DNA from human remains that date back to the ancient city of Jericho to try to understand more about the origins of tuberculosis. Cynthia Graber reports Clues about modern-day tuberculosis could be found in some 6,000 year old bones. Israeli, Palestinian and German scientists have teamed up to investigate the remnants of diseases in bones excavated from the ancient city of Jericho. It’s an exercise in paleoepidemiology, the study of ancient diseases in mummified bodies and other human remains. The Jericho bones were unearthed by Dr. Kathleen Kenyon half a century ago. The DNA in the samples will be tested for tuberculosis, leprosy, leishmania and malaria. But the focus is on tuberculosis, which is the biggest killer today.

Scientists believe that tuberculosis originated in the Fertile Crescent 9-10,000 years ago. And Jericho is one of the earliest cities on earth, about 11,000 years old. So there’s a good chance TB could have gotten a start there. Researchers will be studying how early cities—the first time people lived in crowds—affected the DNA of microbes and their human hosts. They’ll also be looking at the remains of animals, which could have been disease vectors. Scientists on the team believe there’s sufficient DNA in the samples to provide new information about the origin and evolution of TB, which could help us combat it today.


Source: 60-Second Science

Stomach Ulcer Bacteria Migrated with Humans 60,000 Years Ago

In 1985 Australian microbiologist Barry Marshall gobbled a Petri dish full of Helicobacter pylori to prove to the world that the bacteria, rather than stress and spicy foods, were the primary cause of stomach ulcers. Two decades later his recklessness was honoured with the Nobel Prize in Physiology or Medicine, which he shared with his colleague J. Robin Warren. In light of a new study, published in Nature, it is odd that it took so long to finger H. pylori as the source of bouts of abdominal pain, nausea and hemorrhagic vomiting. According to the new work, the pathogen has infected humans for over 60,000 years and its genetic transformation over that time is remarkably similar to that of man—making it a reasonable model for human migration and diversification.

"Like a trail of crumbs, the DNA of our Helicobacter pylori can show where we were born and where our ancestors travelled from over the past 60,000 years," says Marshall, a senior principal research fellow at the University of Western Australia.

According to a 2002 study (published in the New England Journal of Medicine), H. pylori infects 50 percent of the global population. The helical bacterium is the only known microorganism that can survive in the highly acidic mucus lining of the stomach and duodenum, and it is now thought to be the cause of most stomach ulcers and gastritis, an irritation or inflammation of the stomach lining. It is also a risk factor for stomach cancer.

The current study was conducted by an international group of scientists led by University of Cambridge in England and the Max Planck Institute for Biological Infections in Germany. Human populations were broken down by geographic area, moving out of East Africa, believed to be the cradle of human civilization, and into Western Europe, eastern Asia and southern Africa. Researchers were able to estimate that the pathogen emerged from East Africa—not China and southern Africa as previously surmised—between 54,500 and 61,500 years ago. A previous study on human settlement, by Balloux et al. estimated human emergence from the same locale to have occurred 51,500 to 61,500 years ago.

In addition, the research team focused on the microcosm of Europe. They showed that the pathogen was also a viable local model by noting that its pattern of population change on the continent suggested mixing from different geographic sources. This finding is backed by the literature on human migration, which argues that farmers in the Neolithic period moved into Europe from northern Africa and central Asia.

Marshall says molecular epidemiology—"looking at statistical relationships between bacteria from different races"—marks an improvement over studying human migration via ancient human DNA, which degrades if it is more than a few thousand years old. "At present, this is all rather new and the 'clock' has not been calibrated very exactly," he says, "but it is an exciting and fruitful area of new research."

Adapted from materials provided by Scientific American

Diabetes and Vitamin D

Diabetes is characterized by high glucose level in blood. Blood carries glucose to different parts of the body, which obtained through assimilation of the food. Glucose breakdown releases energy and allow the body to perform its necessary work. Glucose level in blood is maintained by insulin, a chemical, produced by pancreas cells of pancreas. Diabetic condition occurs when either pancreas cells fail to produce enough insulin or by the inability of cells of other organs to utilize the secreted insulin. There are three types of diabetes: Type 1, Type 2 and gestational diabetes. In Type 1 diabetes, insulin producing β (beta) cells in the pancreas are destroyed by the body's own immune system and there by insulin production decreases. Type 2 diabetes is the most common form of diabetes. In this form, cells from other organs such as muscles and liver can not use the secreted insulin. Prior to develop type 2 diabetes, pancreas of anyone is known to function normally and secrete as much as insulin required by the body. But over the time, however, it loses its ability to produce sufficient amount of insulin. Thus when patient with type 2 diabetes intake more glucose rich food, the blood glucose level increases beyond the normal level and can be fatal. During the late stage of pregnancy, some women develop diabetes known as gestational diabetes. This form of diabetes usually goes away after the baby is born but the woman who has had it, is more likely to develop type 2 diabetes later in life.

Regular exercise and proper diet help controlling the glucose level in one's body. In severe cases medication is required to avoid the severity of Diabetes. Prolonged uncontrolled diabetes leads to many complication like heart attack, blindness, kidney failure and leg ulcers. A recent study, conducted in the National Public Health Institute, Finland, has shown that a good dose of Vitamin D can help protect anyone against diabetes. Another study has shown that Vitamin D supplements in early childhood may cuts the development of type 1 diabetes in later life. Researchers have found that low blood levels of Vitamin D interfere with the proper function of insulin-producing cells. Low Vitamin D levels also result in an increase in the risk of insulin resistance, even in otherwise healthy individuals. Sunlight helps synthesizing vitamin D in human body. So, consider stepping into the sunshine if you want to increase your own vitamin D levels by natural and thereby reduce the risk of developing diabetes.

Red Alert for Toxic Plastic

The first large study in humans of a chemical widely used in everyday plastics has found that people with higher levels of bisphenol A (BPA) had higher rates of heart disease, diabetes and liver abnormalities, a finding that immediately became the focus of the increasingly heated debate over the safety of the chemical.

The research, published in the Journal of the American Medical Association by a team of British and American scientists, compared the health status of 1,455 men and women with the levels of the chemical, known as BPA, in their urine. The researchers divided the subjects into four statistical groupings according to their BPA levels and found that those in the quartile with the highest concentrations were nearly three times as likely to have cardiovascular disease than those with the lowest levels, and 2.4 times as likely to have diabetes. Higher BPA levels were also associated with abnormal concentrations of three liver enzymes.

The BPA exposure in the study were below those deemed safe by the US Government, adding to a growing body of studies in animals that have linked low-level BPA exposure to various disorders. Trade groups representing the chemical industry and metal can producers dismissed the results. "Due to inherent limitations in study design, this new study cannot support a conclusion that BPA causes any disease," Steven G. Hentges of the American Chemistry Council said in a statement.

“Higher urinary concentrations of BPA were associated with an increased prevalence of cardiovascular disease, diabetes and liver-enzyme abnormalities” wrote the team of British and American researchers of Peninsula Medical school in Exeter, England. They also say follow­-up studies are needed to confirm their work and to determine whether BPA caused the observed health problems.

The British researchers noted that humans are also exposed BPA through the air and contact with the skin. Those findings ran counter to a report by another federal agency, the National Toxicology Program, which found “some concern” that BPA might cause developmental problems in the brain and hormonal systems of infants.

The FDA regulates the compound's use in plastic food containers, bottles, tableware and the plastic linings of food cans. In light of the controversy surrounding the chemical, the agency is reviewing its policy. It issued a draft statement last month that repeated its position that BPA is safe for food and beverage packaging, but it also tapped six outside scientists to review the scientific literature and make a recommendation to agency officials. Notably, more than 100 studies have linked BPA exposure to health effects in animals. The FDA maintains that BPA is safe largely on the basis of two studies funded by the chemical industry, a fact that was repeatedly cited at yesterday's forum.

Adapted from materials provided by The Washington Post

More infortmation on BPA

What is BPA?

BPA is a chemical produced in large quantities to produce polycarbonate plastics and epoxy resins. It is used to give polycarbonate plastics its unbreakable quality.

Where is BPA found?

BPA found in some food and drink packaging, such as water and infant bottles, compact discs (CD), impact resistant safety equipment, dental sealants and medical devices.

How does BPA get in to the body?

The primary source is the diet. BPA can leach into our food from the protective internal epoxy resin coatings of canned foods and from consumer products such as polycarbonate tableware, food storage containers, water bottles and baby bottles. The degree to which BPA leaches from polycarbonate bottles into liquid may depend more on the temperature of the liquid or bottle , than the age of the container. BPA can also found in breast milk.

Source: National Institute of Environmental Health Science (US)

How to avoid BPA exposure?

• Do not microwave polycarbonate plastic food containers. Polycarbonate is strong and durable but over time it may break down from over use at high temperature.
  
• Avoid polycarbonate containers that contain BPA, which usually have number 7 on the bottom (http://recyclenow.org/r_plastics.html).
  
• Reduce your use of canned foods. When possible, use glass, porcelain or stainless steel containers, particularly for hot food and liquids.
  
• Use baby bottles that are BPA free.
  

Prevent Malaria using Virus: Not too far off

Malaria continues to be a major public health concern worldwide, especially in tropical countries. Each year, there are approximately 515 million cases of malaria, killing between one and three million people, the majority of whom are young children in Sub-Saharan Africa. Malaria is a vector-borne infectious disease caused by protozoan parasites (Plasmodium falciparum, Plasmodium ovale, and Plasmodium malariae) belong to the genus Plasmodium. Mosquito is the vector or carrier of these parasites into the human body. Mosquitoes also act as a vector for viruses and caused diseases like yellow fever, dengue fever, epidemic polyarthritis, Rift Valley fever, Ross River Fever, St. Louis encephalitis, West Nile virus (WNV), Japanese encephalitis, La Crosse encephalitis and several other encephalitis. Currently pesticide use and maintaining clean environment are the two most effective preventive measures followed in most of the countries to control the reproduction of mosquitoes. Although some are under development, no vaccine is currently available for malaria.

Is there any way to get rid of mosquitoes and so the malaria? Some people use herbal or chemical based mosquito repellent lotion or oil. The efficacy of mosquito repellent lotions is low and provides very limited protection in terms of duration and number of people. Furthermore, most of us are not ready to accept the mosquito repellent lotions as a replacement to our everyday skin care lotions! So, how to manage this tiny insect? Is there really no way to control them? Until now the answer was “No”. But researchers at Johns Hopkins University are now hoping that mosquitoes can be controlled and that using virus. Researchers have found a new virus that infects the world's most dangerous mosquito, called Anopheles gambiae. This mosquito is the chief malaria vector in Africa. This aggressive human-biter also bites animals and hide in huts. In the PLoS Pathogen journal, scientist described the virus as the first densovirus found in this African mosquito. Although the virus is harmless to the mosquito, but scientists are confident to manipulate the genetic elements of the virus in such a way that once the genetically manipulated virus infects this mosquito, it will reproduce inside the mosquito and will kill them within 10 days. This is good news indeed, although this work could take 5 to 15 years because of the regulatory and ethical barriers to releasing a virus in to wild mosquitoes. Are you ready to wait for 15 or more years to see the viral weapon against mosquitoes or you would consider mosquitoes repellent as a permanent replacement of your lovely beauty lotions to protect yourself from mosquito bite?

Virus infects virus: Mimivirus paradigm

A virus is a sub-microscopic infectious agent that is unable to grow or reproduce outside a host cell. A complete virus particle, known as a virion, consists of genetic material (DNA or RNA) surrounded by a protective coat of protein called a capsid.Viruses infect all cellular life forms and are grouped into animal, plant and bacterial types, according to the type of host infected. Viruses that infect bacteria are known as bacateriophage or simply, phage. Once a phage infects a bacteria, it may have either a lytic cycle or a lysogenic cycle, inside the bacterial cell. A phage that follows a lytic cycle is called lytic phage (virulent phage) and that follow a lysogenic cycle is called lysogenic phage (temperate phage). However, a few viruses are capable of carrying out both lytic and lysogenic cycles, for example, lambda phage. In lytic cycle, the phage (eg. T4 phage) upon entering entering in to the bacterial cell, replicate and lyse (destroy) the bacterial cell. In contrast, in lysogenic cycle the viral genome integrates (or lysogenize) with host DNA and replicate along with it fairly harmlessly, or may even become established as a plasmid and retain inside the bacterial cell. Integrated lysogenic phages are also called propahge. Sometimes prophages may provide benefits to the host bacterium while they are dormant by adding new functions to the bacterial genome in a phenomenon called lysogenic conversion. A famous example is the conversion of a harmless strain of Vibrio cholerae by a phage (CTXØ) into a highly virulent one, which causes cholera.

So far this was all about virus that infects bacteria.

What about virus that infects another virus? There are viruses that infect giant viruses. Marine virologists have reported such small viruses occurring with larger ones in marine protist populations. Small viruses or so called “satellite viruses” require other larger viruses, especially for their reproduction, since they lack essential functions for multiplication. Usually satellite viruses are harmless to their giant virus host. Most recently, La Scola et al. report in Nature (2008) that a small virus, named Sputnik infects a giant DNA virus named Mimivirus (Acanthamoeba polyphaga mimivirus, or APM) and the infection decreases the yield of APM virions and generates APM virions with aberrant morphologies in amoeba cells. Since, unlike usual satellite viruses, Sputnik uses its host’s (Mimivirus) virus machinery and impairs its fitness authors call Sputnik a “virophage.” Sputnik (named after “traveling companion” in Russian) is an icosahedral virus with a DNA genome encoding 21 genes and was isolated in a cooling tower in Paris. Mimivirus once thought to be a bacterium since it contains more number of genes than many bacteria and bear properties like cellular organism. It is five to ten times larger than any other known virus It was La Scola et al. who classified it as a virus in 2003. Discovery of giant Mimivirus and its relation to Sputnik are expected to provide new clues to the virus-virus interaction in virosphere and its impact in the evolution of viruses.

Research News: Role of a Microbe inside a Marine Host

The symbiotic relationship between two different organisms is indeed a fascinating event in nature. Very recently, scientists from USA published their research outcome (PNAS August 12, 2008 vol. 105 no. 32 11323-11328) on symbiotic relationship between a microbe (Vibrio fischeri) and a squid (scientific name: Euprymna scolopes). In the article, Chun et al described the effects of colonization, luminescence, and autoinducer on host transcription during squid-vibrio symbiosis, by using glass-slide microarray. The article provided significant insight in to the role of bioluminescence in preparing the host for bacteria-induced development. Based on the comparative analysis, authors in the article also revealed a set of genes possibly associated with host response towards its symbiotic partner. This article will certainly rich the understanding of the host-microbe interaction and genetic machinery involved in the development of such relationship.

Glossary

Bioluminescence
Bioluminescence refers to the ability of a living organism to emit lightis. Bioluminescence is produced by a living organism as the result of a chemical reaction during which chemical energy is converted to light energy. It should not be confused with fluorescence, phosphorescence or refraction of light, which describes other forms of light emission. Bioluminescence occurs in marine vertebrates and invertebrates, as well as microorganisms and terrestrial animals. Symbiotic organisms carried within larger organisms are also known to bioluminesce.

Squid
Squid are one kind of marine animal. Many species of squid are consumed by human as sea-food.

Symbiosis
Symbiosis is a relationship between two organisms which could be mutalistic (both organisms are benefited by the relationship), parasitic (one member of the association benefits while the other is harmed), or commensal (one organism benefits and the other is not significantly harmed or helped) in nature.