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Thursday, 10 September 2015

Manipulation of the tyrothricin production profile of Bacillus aneurinolyticus

  • A group of non-ribosomally produced antimicrobial peptides, the tyrocidines from the tyrothricin complex, have potential as antimicrobial agents in both medicine and industry. Previous work by our group illustrated that the more polar tyrocidines rich in Trp residues in their structure were more active toward Gram-positive bacteria, while the more non-polar tyrocidines rich in Phe residues had greater activity toward , one of the major causative pathogens of malaria in humans. Our group also found that the tyrocidines have pronounced antifungal activity, dictated by the primary sequence of the tyrocidine. By simply manipulating the Phe or Trp concentration in the culture medium of the tyrothricin producer,  ATCC 10068, we were able to modulate the production of subsets of tyrocidines, thereby tailoring the tyrothricin complex to target specific pathogens. We optimized the tailored tyrothricin production using a novel, small-scale, high-throughput deep 96-well plate culturing method followed by analyses of the peptide mixtures using ultra-performance liquid chromatography linked to mass spectrometry. We were able to gradually shift the production profile of the tyrocidines and analogues, as well as the gramicidins between two extremes in terms of peptide subsets and peptide hydrophobicity. This study demonstrated that tyrothricin peptide subsets with targeted activity can be efficiently produced by simple manipulation of the aromatic amino acid profile of the culture medium.

  • Supplementary material is available with the online version of this paper.
  •  J. St├╝lke
  • Abbreviations:
    GSgramicidin S
    LCliquid chromatography
    Phcphenycidine
    Tpctryptocidine
    Trctyrocidine
    UPLCultra-performance liquid chromatography
    VGAVal-gramicidin A

© 2013 SGM | Published by the Society for General Microbiology

Accent makes Arnold Vosloo a perfect Hollywood 'villain'

Arnold Vosloo.
Image by: RUVAN BOSHOFF

South African-born actor Arnold Vosloo's homegrown accent has helped him flourish in Hollywood playing movie villains.

"He has the strong facial features and of course the accent... none of your top bad guys speak with a typical American accent," Regardt van den Bergh, a director who worked with Vosloo, told the the Sunday Times.
Van den Berg cast Vosloo in the 1983 film "Boetie Gaan Border Toe".
He said that despite his typecasting, Vosloo was actually a serious actor.
"I am sure he would love to land a role with a bit more flesh to showcase his talents."
Vosloo first made it big in "The Mummy" and its sequel. He is currently on screen in "GI Joe: Retaliation" which has earned more than R1 billion at the box office.

Arnold Vosloo a great villain




South African-born actor Arnold Vosloo's homegrown accent has helped him flourish in Hollywood playing movie villains, The Sunday Times reported.

"He has the strong facial features and of course the accent... none of your top bad guys speak with a typical American accent," Regardt van den Bergh, a director who worked with Vosloo, told the newspaper.

Van den Berg cast Vosloo in the 1983 film "Boetie Gaan Border Toe".

He said that despite his typecasting, Vosloo was actually a serious actor.

"I am sure he would love to land a role with a bit more flesh to showcase his talents."

Vosloo first made it big in "The Mummy" and its sequel. He is currently on screen in "GI Joe: Retaliation" which has earned more than R1 billion at the box office.

Lieutenant General Mkhwanazi slams claims that senior cops want Phiyega out

Former acting national police commissioner, Lieutenant General Nhlanhla Mkhwanazi has denied allegations that he has been ‘discarded’ by the South African Police Service (Saps).

Mkhwanazi says he is happy in his current role as a Divisional Commissioner for Facilities Management.

Mkhwanazi is challenging the reports by local media which reference him among a number of senior police officials who expressed dissatisfaction with the leadership of National Police Commissioner Riah Phiyega.

I am satisfied with any position that improves me as a manager. I do not feel that I was demoted. I am happy, that is why I am at work. If i wasn't, I would've resigned. But, it doesn't mean I am always going to be happy with whatever decision management takes. We cannot always agree on things.

— Lieutenant General Nhlanhla Mkhwanazi , SAPS
Reports also claimed that Mkhwanazi was 'discarded' from Saps, suggesting that he was unemployed without verifying the facts from him.

For more on this story, visit the EWN website.

Listen to the full conversation from The John Robbie Show:


Arnold Vosloo death reports are a hoax

John received an article reporting that critically-acclaimed South African-born actor, Arnold Vosloo died in an accident. His sister however later called into the show to confirm that this is a hoax. Arnold is alive and well in the US.

Arnold is best known for his roles as Imhotep in the movie The Mummy and _The Mummy Returns, _as well as Pik van Cleef in Hard Target, Dr. Peyton Westlake/Darkman in Darkman II and Darkman III, among others.

Listen to the full conversation below:

 
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