Showing posts with label Science. Show all posts
Showing posts with label Science. Show all posts

Sunday, June 29, 2008

Fake virus could make safe new vaccines

A "wimpy" artificial virus protected mice against polio, and the approach might be used to make a range of safer new vaccines against viruses, U.S. researchers reported on Friday. The team at the State University of New York, Stony Brook, had created the first artificial virus, a synthetic version of polio, in 2002. Reporting in the journal Science, they said they used it to vaccinate mice, and then infected the mice with what should have been a deadly dose of polio. The mice survived.
"Ultimately we created a wimpy poliovirus that can be customized and does not cause disease unless given at high doses," Bruce Futcher, a professor of molecular genetics and microbiology who worked on the study.
"These viruses are still far from suitable vaccines for humans, but there is a lot of potential for this approach," he added in a statement.
The researchers used a unique method to make their virus, relying on a built-in redundancy in DNA, the material that carries genetic instructions in organisms.
DNA's code is written using just four nucleic acids, represented by the letters A, C, T and G. These are combined in various ways to make amino acids, which in turn make proteins.
It is possible to make an amino acid with more than one combination of these letters -- for example, GCC and GCG both code for the amino acid alanine. For unknown reasons, organisms favor certain combinations.


all sources : newsdaily

Saturday, March 1, 2008

Enterobacter sakazakii Infection and Powdered Infant Formulas

On April 9, 2002, the United States Food and Drug Administration (USFDA) issued an alert to US Health Care Professionals regarding the risk associated with Enterobacter sakazakii infections among neonates fed milk-based, powdered infant formulas. Historically, there have been several small E. sakazakii outbreaks reported among infants fed milk-based, powdered formula products from various manufacturers. In addition to powdered milk-based formulas, powdered human milk fortifiers may also pose a hazard.

E. sakazakii is a motile peritrichous, gram-negative rod from the family Enterobacteriaceae. This organism used to be known as a "yellow pigmented Enterobacter cloacae" until 1980, when it was introduced as a new species based on differences in DNA-DNA hybridization, biochemical reactions, and antibiotic susceptibility. E. sakazakii is a rare, but life-threatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, the reported case-fatality rate varies from 40-80 % among newborns diagnosed with this type of severe infection. The type of meningitis caused by E. sakazakii may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment.

There is still a paucity of information on the ecology of this bacterium. However, studies have shown that this organism can be isolated from hospital and processing plant environments. Reports have also suggested a correlation between E. sakazakii infection and powdered infant formulas. Similarly, it has been reported that premature infants and those with underlying medical conditions may be at highest risk for developing an E. sakazakii infection.

Several outbreaks of E. sakazakii, in Neonatal Intensive Care Units (NICUs), have been reported worldwide including countries such as England, Netherlands, Greece, US and Canada. In Canada, two incidents of neonatal meningitis caused by E. sakazakii were reported in two Canadian hospitals (1990, 1991). It should be noted that healthy infants may not always be immune to E. sakazakii infections. It has been reported that in Iceland, a healthy, full-term, newborn infant became ill prior to hospital discharge and suffered permanent neurological sequelae as a result of an E. sakazakii infection.

Health Canada is drawing attention to the fact that powdered infant formulas are not commercially sterile products. Unlike liquid formulas, which are subjected to sufficient heat to render them commercially sterile, powdered infant formulas are not processed at high enough temperatures for sufficient time to achieve commercial sterility. Ready-to-use liquid infant formulas are available only in a commercially sterile form and indicated for premature or low-birth weight infants. However,"transition" infant formulas which are used for premature or low-birth weight infants after hospital discharge, may be either powdered or liquid. Human milk fortifiers which are added to pre-term breast milk are also available in powdered or liquid forms. A number of formulas, including formulas for infants with metabolic conditions are only available in powdered form. Powdered soy-based infant formulas may also become contaminated with E. sakazakii through improper cleaning of production lines and may, therefore, pose a safety hazard.


but dont worry, check some proffesional advices and recommendations from our health scientist.

Enterobacter sakazakii

Enterobacter sakazakii, previously referred to as a yellow-pigmented Enterobacter cloacae was designated as a unique species in 1980. This reclassification was based on differences from E. cloacae in DNA relatedness, pigment production and biochemical reactions. E. sakazakii has been implicated in a severe form of neonatal meningitis. Although studies have failed to identify an environmental source for the organism, dried-infant formula has been implicated in both outbreaks and sporadic cases of E. sakazakii meningitis. The high mortality rate (40-80%), the severity of the infection in infants, plus the scarcity of information on the ecology and pathogenicity of this organism warranted a review of the clinical and microbiological features of this putative foodborne pathogen.

Int J Food Microbiol. 34(2):103-13.

by Nazarowec-White M, Farber JM.

'Rain-making' bacteria found around the world

Some microbes are frequent flyers in clouds

The same bacteria that cause frost damage on plants can help clouds to produce rain and snow. Studies on freshly fallen snow suggest that ‘bio-precipitation’ might be much more common than was suspected.

Before a cloud can produce rain or snow, rain drops or ice particles must form. This requires the presence of aerosols: tiny particles that serve as the nuclei for condensation. Most such particles are of mineral origin, but airborne microbes — bacteria, fungi or tiny algae — can do the job just as well. Unlike mineral aerosols, living organisms can catalyse ice formation even at temperatures close to 0 ÂșC.

The effect of the biological ‘ice nucleators’ on precipitation has been a mystery, not least because no one has yet been able to detect them in clouds.

Further more see on article by Quirin Schiermeier here.