Microbiology News from Around the World

Phytoplankton Blooms May Promote Cloud Formation

Source http://www.asm.org/microbe/index.asp?bid=48523"
http://www.asm.org/microbe/index.asp?bid=48523

Phytoplankton blooms appear to promote cloud formation over the SouthernOcean, according to Nicholas Meskhidze and Athanasios Nenes of the GeorgiaInstitute of Technology in Atlanta, who report their findings in the 1 December2006 Science. Using remotely sensed data, they determined that cloud dropletnumber concentrations are twice as high over phytoplankton blooms as they are atsites away from those blooms, and they attributed these and other changes to thesize distribution and chemical composition of cloud condensation nuclei that form.The researchers further propose that secondary organic aerosols, which form whenphytoplankton-produced molecules of isoprene are oxidized, “affect chemicalcomposition of marine cloud condensation nuclei and influence cloud dropletnumber.”

Microbes Implicated in Human Behavioural Changes

Source http://www.asm.org/microbe/index.asp?bid=50781
http://www.asm.org/microbe/index.asp?bid=50781

In several separate developments, researchers linked human behaviours with thebehaviour of micro-organisms in unexpected ways, including:·Christopher Lowry of Bristol University in Bristol, United Kingdom, and hiscollaborators are testing whether challenging individuals with inactivatedMycobacterium vaccae can alleviate symptoms of depression. When such killedbacteria are injected into mice, they not only trigger an immune response but alsoinduce the brain to produce serotonin, a neurotransmitter that is the target of theclass of antidepressant drugs called serotonin-reuptake inhibitors. Details appearin 28 March 2007 online version of Neuroscience doi:10.1016/j.neuroscience.2007.01.067.·Clinical researchers at the National Institute of Mental Health in Bethesda, Md.,are enrolling patients in two studies of a set of paediatric autoimmuneneuropsychiatric disorders that are associated with streptococcal infections. In oncecase, the researchers will be examining a potential link between the bacteria thatcause strep throat and the onset of obsessive-compulsive disorder in some children.They suspect that antibodies mistakenly attack the basal ganglia, a set of structuresat the base of the brain.