Eukaryotic bacteria? 9 September 2003 13:00 GMT by Lynne Lederman
European researchers have modified the cellular machinery of Escherichia coli to produce a system
for the production of proteins relevant for eukaryotic, particularly human, applications. E.
coli, like most bacteria, fail to glycosylate the proteins they synthesize, but this system could
change all that.
In eukaryotes, glycosylation is the most frequent post-translational modification of proteins.
Glycosylated proteins are required for the cellular communication essential for immune responses to
infectious diseases and for resisting the development of some cancers. Defects in glycosylation are
associated with diseases of the immune and other systems. Currently, because of the inability of
most types of bacteria to glycosylate proteins, the only way to synthesize glycoproteins for
research or therapeutic use has been to make them in cloned mammalian cells, which is costly and
technically difficult, restricting the types of human proteins that can be produced.
Read the rest at BioMedNet news.bmn.comstoryOpen ↗
Bacterial shield against HIV 8 September 2003 12:10 GMT by Helen Dell
of HIV to women - by engineering bacteria that are naturally present in the vagina. Women are
particularly at risk from HIV infection because the efficiency of HIV transmission from men to women
is greater than for women to men, say the researchers. But in the absence of a vaccine, there are
very few ways for women to protect themselves.
The main way that women get infected with HIV is through the vaginal mucosa. In healthy women, this
tissue layer is populated with a number of bacterial species, dominated by lactobacilli, forming a
dynamic ecosystem. However, if the lactobacilli are depleted or disturbed, harmful bacteria can
become established and there is an increased risk of infection with HIV.
What drives the evolution of optional life-history tactics? 9 September 2003 by Sharon Downes
and Bob Wong
All animals have to change their survival and reproductive strategies from time-to-time in order to
survive, but some animals alternate both continuously, report ecologists who are only now beginning
to integrate the way they study the two.
During an animal's lifetime it must allocate limited resources between the conflicting demands of
survival and reproduction. Those individuals that are programmed with allocation rules that are best
suited for the environment in which they are living are most likely to leave surviving offspring.
The resulting schedules of age-specific maturity, dispersal and reproduction constitute the animal's
life-history. All species show some continuous variation, but a number of species also show a
consistent pattern of discrete, alternative life-history pathways.
Comparative analysis of the genome sequences of Bordetella pertussis, Bordetella parapertussis and
Bordetella bronchiseptica Parkhill, J. et al. Nature Genetics 2003 35(1):32-40
Commentary by Sylvain Brisse 10 September 2003 Genomic clues on the evolution of whooping
cough agent
Bordetella pertussis, the primary etiologic agent of whooping cough, is a strict human pathogen of
recent evolutionary origin. Despite extensive vaccination programs, whooping cough is still endemic
in many countries, having caused approximately 285 000 deaths in 2001. B. parapertussis can also
cause whooping cough, and B. bronchiseptica causes chronic respiratory infections in many animals.
Although these species of Bordetella are genetically closely related, they differ in their host
range and pathogenic properties, and the genetic background for these differences is not well
understood.
The complete genomes sequences were obtained from B. pertussis Tohama I, a clinical isolate that has
subsequently been used widely for studies in the laboratory; B. parapertussis strain 12822, isolated
in 1993 from a baby in Germany; and B. bronchiseptica strain RB50, isolated from a rabbit. Parkhill
et al. performed genome comparisons, which indicated that B. pertussis and
B. parapertussis are each derived from a B. bronchiseptica-like ancestor. Compared with B.
parapertussis, B. bronchiseptica has several large discrete regions of unique DNA. Many of these
are prophage insertions, but some are clearly not.
Kind Regards, Robert Karl Stonjek.