title: Lichen fungi have low cyanobiont selectivity in maritime Antarctica

authors: Wirtz, Nora

subjects: lichens

abstract: The cyanobionts of lichens and free-living Nostoc strains from Livingston Island (maritime Antarctica) were examined to determine both the cyanobiont specificity of lichens and the spatial distribution of Nostoc strains under extreme environmental conditions.
We collected five different lichen species with cyanobacteria as primary or secondary photobiont (Massalongia carnosa, Leptogium puberulum, Psoroma cinnamomeum, Placopsis parellina and Placopsis contortuplicata) and free-living cyanobacteria from different sample sites and analysed them using the tRNALeu (UAA) intron as a genetic marker to identify the cyanobacterial strains.
Our results showed that the same Nostoc strain was shared by all five lichen species and that an additional strain was present in two of the lichens. Both Nostoc strains associated with lichen fungi also occurred free-living in their surrounding. Bi- and tri-partite lichens were not different in their cyanobiont selectivity.
Contrary to studies on different lichen species in temperate regions, the Antarctic lichen species here did not use species-specific cyanobionts; this could be because of a selection pressure in this extreme environment. Limiting factors under these ecological conditions favor more versatile mycobionts. This results in selection against photobiont specificity, a selection pressure that may be more important for lichen distribution than the effect of cold temperatures on metabolism.

text: Lichen fungi have low cyanobiont selectivity in maritime Antarctica The cyanobionts of lichens and free-living Nostoc strains from Livingston Island (maritime Antarctica) were examined to determine both the cyanobiont specificity of lichens and the spatial distribution of Nostoc strains under extreme environmental conditions.
We collected five different lichen species with cyanobacteria as primary or secondary photobiont (Massalongia carnosa, Leptogium puberulum, Psoroma cinnamomeum, Placopsis parellina and Placopsis contortuplicata) and free-living cyanobacteria from different sample sites and analysed them using the tRNALeu (UAA) intron as a genetic marker to identify the cyanobacterial strains.
Our results showed that the same Nostoc strain was shared by all five lichen species and that an additional strain was present in two of the lichens. Both Nostoc strains associated with lichen fungi also occurred free-living in their surrounding. Bi- and tri-partite lichens were not different in their cyanobiont selectivity.
Contrary to studies on different lichen species in temperate regions, the Antarctic lichen species here did not use species-specific cyanobionts; this could be because of a selection pressure in this extreme environment. Limiting factors under these ecological conditions favor more versatile mycobionts. This results in selection against photobiont specificity, a selection pressure that may be more important for lichen distribution than the effect of cold temperatures on metabolism.

year: 2010

title: The evidence supporting the use of honey as a wound dressing

authors: Molan, Peter C.

subjects: evidence

abstract: Some clinicians are under the impression that there is little or no evidence to support the use of honey as a wound dressing. This impression is reinforced by it being concluded in systematic reviews that the evidence is not of a high standard. But likewise the evidence for modern wound dressing products is of not of a high standard. For evidence-based medicine to be practised in wound care, when deciding which product to use to dress a wound it is necessary to compare the evidence that does exist, rather than be influenced by advertising and other forms of sales promotion. To allow sound decisions to be made, this review has covered the various reports that have been published on the clinical usage of honey. Positive findings on honey in wound care have been reported from 17 randomised controlled trials involving a total of 1965 participants, and 5 clinical trials of other forms involving 97 participants treated with honey. The effectiveness of honey in assisting wound healing has also been demonstrated in 16 trials on a total of 533 wounds on experimental animals. There is also a large amount of evidence in the form of case studies that have been reported. Ten publications have reported on multiple cases, totalling 276 cases. There are also 35 reports of single cases. These various reports provide a large body of evidence to support honey having the beneficial actions of clearing and preventing wound infection, rapidly debriding wounds, suppressing inflammation and thus decreasing oedema, wound exudate and hypertophic scarring, and stimulating the growth of granulation tissue and epithelialisation. It has been shown to give good results on a very wide range of types of wound. Clinicians should look for the clinical evidence that exists to support the use of other wound care products to compare with the evidence that exists for honey.

text: The evidence supporting the use of honey as a wound dressing Some clinicians are under the impression that there is little or no evidence to support the use of honey as a wound dressing. This impression is reinforced by it being concluded in systematic reviews that the evidence is not of a high standard. But likewise the evidence for modern wound dressing products is of not of a high standard. For evidence-based medicine to be practised in wound care, when deciding which product to use to dress a wound it is necessary to compare the evidence that does exist, rather than be influenced by advertising and other forms of sales promotion. To allow sound decisions to be made, this review has covered the various reports that have been published on the clinical usage of honey. Positive findings on honey in wound care have been reported from 17 randomised controlled trials involving a total of 1965 participants, and 5 clinical trials of other forms involving 97 participants treated with honey. The effectiveness of honey in assisting wound healing has also been demonstrated in 16 trials on a total of 533 wounds on experimental animals. There is also a large amount of evidence in the form of case studies that have been reported. Ten publications have reported on multiple cases, totalling 276 cases. There are also 35 reports of single cases. These various reports provide a large body of evidence to support honey having the beneficial actions of clearing and preventing wound infection, rapidly debriding wounds, suppressing inflammation and thus decreasing oedema, wound exudate and hypertophic scarring, and stimulating the growth of granulation tissue and epithelialisation. It has been shown to give good results on a very wide range of types of wound. Clinicians should look for the clinical evidence that exists to support the use of other wound care products to compare with the evidence that exists for honey.

year: 2006-02-01

title: Poster Abstracts

authors: Lapsley, Hilary

subjects: Maori

abstract: These are the poster abstracts from the Proceedings of the National Māori Graduates of Psychology Symposium 2002.

text: Poster Abstracts These are the poster abstracts from the Proceedings of the National Māori Graduates of Psychology Symposium 2002.

year: 2003