The NDM-1 mutation and invincible bacteria

Klebsiella pneumoniae

In 2009, a Swedish patient was described (Yong et al) who, while traveling in New Delhi, India, acquired a bacterial infection that was resistant to carbapenems. Carbapenems are considered to be the most powerful class of antibiotics available in medical science. In a world of antibiotic resistant bacterial strains, these medicines are the last line of defense. The bacterial strain infecting the patient was not only resistant to these drugs, but harbored a gene for a previously unknown subroup of metallo-beta-lactamase (MBL), a carbapenemase, on its type 14 complex. The new gene was termed New Delhi metallo-beta-lactamase-1 (NDM-1).

Single resistant bacteria have been around for a long time, but the new gene is found alongside other resistance genes. So far, multiple resistance in the presence of NDM-1 has been found in Klebsiella pneumoniae, giving this strain an ability to withstand nearly all available medical treatments for bacterial infections.

In 2010, NDM-1 was known to be spread throughout India. Bacteria containing the gene also spread to the UK via patients who travel abroad for medical procedures, as well as the United States, Canada, and Australia. The New Delhi gene is becoming a common variant in the bacterial genome, and as of 2010 was found in an estimated 1-3 percent of enterobacteria infections.

Read more about NDM-1, the so-called superbug gene.

NDM-1 has a novel sequence, and likely a novel structure - medicine will likely need something entirely new to fight any infectious bacteria that carry the gene. Does this mean current antibiotics will likely be useless in 10 years? Read more about the background and potential for invincible bacteria.

Schizophrenia and genetics

Schizophrenia is defined as an inability to differentiate between what is real and unreal – affecting decision-making, emotions, and behavior. A lot of research has gone into determining the causes of the disorder, but they are still unknown. However, a genetic component, possibly triggered by an environmental component, appears to be at play. Ultimately, the genetic component is likely several genes rather than a single gene. This is because the disorder can vary in severity and manifestation, with several subtypes recognized by the medical community. Read more about the genetics underlying schizophrenia.

Bone health may affect male fertility

Sex steroids in men have well known functions in reproduction and fertility, specifically the ‘male’ hormone testosterone. A lesser known function is the effect of testosterone and other steroid hormones on the development of the skeleton. In March 2011, a group led by researchers at Columbia University reported a previously unknown bidirectional regulation between the gonads and skeleton in men. Read more about the newly discovered influence of bone on sperm production.

Identification of calcium channel activation in 'fight or flight'

Researchers have further elucidated the calcium channels activated in the fight or flight response, the body's response to stress and acutely dangerous situations. Calcium plays a role in skeletal and cardiac muscle function, which are both affected by the stress response. Mediated by beta-adrenergic receptors, the broad calcium channel response allows quicker reflexes. Read more about the recent findings on the role of calcium channels in the fight or flight response.

Progesterone and ion channels in conception

For decades mystery has surrounded exactly how sperm seek out an egg for fertilization. Unlocking the mechanism could lead to additional methods of overcoming fertility and preventing unwanted pregnancy via new types of contraception. The cation channel of sperm (CatSper) family of ion channels on mammalian sperm was first discovered in 2001. Earlier this year, researchers identified progesterone as a trigger for these channels, resulting in increased sperm motility and the activation of egg penetration, leading to conception. Read more about what researchers have uncovered about the role of progesterone and ion channels in how sperm seek out an egg.

A new attack against HIV

The human immunodeficiency virus (HIV) encodes vif, a virulence factor that deactivates the enzyme APOBEC-3G. This enzyme may be the key to the body's natural defense against HIV. A new study published in Nature discerning the crystal structure of the enzyme may be one of the first to show the potential of blocking vif and allowing APOBEC-3G to attack HIV in the fight against the ongoing epidemic of AIDS. The enzyme blocks HIV replication and, if vif is prevented from acting, the enzyme will continue to prevent HIV from causing AIDS. Knowing the structure of the enzyme will aid the development of drugs that prevent vif from binding.

Antibacterial Bacteria?

A bacterium may actually hold the key to new antibiotics. Rhodococcus fascians harbors genes for polyketides, a class of antibiotic. A lab at MIT has found a way to trigger their expression, which was a difficult task for the researchers. However, their seeming success only lead to more questions as the DNA portion associated with the antibacterial activity turned out to be from Streptomyces, the culture they were testing on.

Evolutionary rate of mutation

The European Journal of Human Genetics had an interesting news editorial about a recent study ab0ut the loss of chromosomal regions in the human genome. It seems that the rate of mutation, from the development of single nucleotide polymorphisms to visible chromosomal loss, is more constant than previously thought. The research supports the rate of mutation needed for adaptive change in a species.

Bad news for fat kids

I was reading through the recent posts at The Scientist newsblog and am a little dismayed at some recent findings:

The number of fat cells in a person's body is determined during childhood and stays constant throughout life, with about 10 percent of fat cells dying and being replaced annually, according to study published in Nature yesterday (May 4).

This is bad news for me. I was an overweight kid...and am an overweight adult. I constantly struggle with trying to maintain a lower weight let alone lose more. Well, at least my sister got to be skinny.

The target age for final adipocyte numbers was 16.5 years. And they saw discrepencies in the rate at which the body produces the cells. Hopefully this information will lead to treatments for those who have more than just a nutrition problem.