title: Fungal biodiversity in extreme environments and wood degradation potential

authors: Jurgens, Joel Allan

subjects: fungi

abstract: This doctoral thesis reports results from a multidisciplinary investigation of fungi from extreme locations, focusing on one of the driest and thermally broad regions of the world, the Taklimakan Desert, with comparisons to polar region deserts. Additionally, the capability of select fungal isolates to decay lignocellulosic substrates and produce degradative related enzymes at various temperatures was demonstrated.  

The Taklimakan Desert is located in the western portion of the People's Republic of China, a region of extremes dominated by both limited precipitation, less than 25 mm of rain annually and tremendous temperature variation. The organisms that inhabit this region are required to function in conditions that preclude most forms of life. Fungi are particularly interesting organisms for consideration of life in extreme environments since they absorb nutrients from their surroundings with diffusion taking place through the cell wall and plasma membrane requiring free water.  The regions near the poles are another example of areas with extreme environmental conditions, with the north and south polar regions having similarities and differences to each other and to the Taklimakan Desert. All three regions experiences extreme cold but only the Taklimakan Desert has exceedingly warm temperatures. The Taklimakan Desert is diurnal and the polar regions have long periods of light and dark in summer and winter months, respectively. The annual precipitation in the specific polar sites is between 100-200 mm, 5-20 fold more than the Taklimakan Desert.

From soil, rock and wood collected in the Taklimakan Desert, 194 independent fungal isolates were generated and identified based on extracted DNA and analysis of the internal transcribed spacer (ITS) region of the rDNA. Dominant taxa were from closely related Thielavia, Embellisia and Alternaria genera. Total DNA extracted directly from environmental samples and subjected to molecular fingerprinting identified 51 consensus sequences almost entirely of taxa not represented by culturing, with the dominant taxa in the Penicillium and Colletotrichum genera.  
 
The sequence data from the Taklimakan Desert cultured fungi were phylogenetically investigated by means of neighbor-joining analysis and compared to fungal sequences derived from various substrates collected at sites in Antarctica and the Arctic with wood as the common substrate from which isolates were obtained among all three locations. Based on comparisons of consensus sequences to the polar fungi and fungal databases, 72 isolates appear to represent novel taxa that may be endemic to the Taklimakan Desert and warrant further investigation. 

Selected fungal isolates from the Taklimakan Desert, Arctic and Antarctic research were investigated to determine and compare their ability to degrade two types of lignocellulose substrates, Pinus resinosa and Populus tremuloides, the latter being a genera of tree identified in some locations of the Taklimakan Desert and the former as a model softwood example. Fungi from all regions were able to degrade these substrates to varying degrees though minimal weight loss was common. These isolates did not produce cellulase or lignin peroxidase concurrent to the temperatures prevalent in the regions from which they were collected, posing interesting possibilities for their wood degradation pathways.

text: Fungal biodiversity in extreme environments and wood degradation potential This doctoral thesis reports results from a multidisciplinary investigation of fungi from extreme locations, focusing on one of the driest and thermally broad regions of the world, the Taklimakan Desert, with comparisons to polar region deserts. Additionally, the capability of select fungal isolates to decay lignocellulosic substrates and produce degradative related enzymes at various temperatures was demonstrated.  

The Taklimakan Desert is located in the western portion of the People's Republic of China, a region of extremes dominated by both limited precipitation, less than 25 mm of rain annually and tremendous temperature variation. The organisms that inhabit this region are required to function in conditions that preclude most forms of life. Fungi are particularly interesting organisms for consideration of life in extreme environments since they absorb nutrients from their surroundings with diffusion taking place through the cell wall and plasma membrane requiring free water.  The regions near the poles are another example of areas with extreme environmental conditions, with the north and south polar regions having similarities and differences to each other and to the Taklimakan Desert. All three regions experiences extreme cold but only the Taklimakan Desert has exceedingly warm temperatures. The Taklimakan Desert is diurnal and the polar regions have long periods of light and dark in summer and winter months, respectively. The annual precipitation in the specific polar sites is between 100-200 mm, 5-20 fold more than the Taklimakan Desert.

From soil, rock and wood collected in the Taklimakan Desert, 194 independent fungal isolates were generated and identified based on extracted DNA and analysis of the internal transcribed spacer (ITS) region of the rDNA. Dominant taxa were from closely related Thielavia, Embellisia and Alternaria genera. Total DNA extracted directly from environmental samples and subjected to molecular fingerprinting identified 51 consensus sequences almost entirely of taxa not represented by culturing, with the dominant taxa in the Penicillium and Colletotrichum genera.  
 
The sequence data from the Taklimakan Desert cultured fungi were phylogenetically investigated by means of neighbor-joining analysis and compared to fungal sequences derived from various substrates collected at sites in Antarctica and the Arctic with wood as the common substrate from which isolates were obtained among all three locations. Based on comparisons of consensus sequences to the polar fungi and fungal databases, 72 isolates appear to represent novel taxa that may be endemic to the Taklimakan Desert and warrant further investigation. 

Selected fungal isolates from the Taklimakan Desert, Arctic and Antarctic research were investigated to determine and compare their ability to degrade two types of lignocellulose substrates, Pinus resinosa and Populus tremuloides, the latter being a genera of tree identified in some locations of the Taklimakan Desert and the former as a model softwood example. Fungi from all regions were able to degrade these substrates to varying degrees though minimal weight loss was common. These isolates did not produce cellulase or lignin peroxidase concurrent to the temperatures prevalent in the regions from which they were collected, posing interesting possibilities for their wood degradation pathways.

year: 2010

title: Trust and reputation in dynamic scientific communities

authors: Rana, Omer F.

subjects: computer science

abstract: The formation of collaboration networks (or communities) is an important latent effect in many computational science undertakings. Generally, collaboration networks bring together participants who wish to achieve some common goal or outcome (often over short time frames). Increasingly, scientific collaborations are becoming interdisciplinary, and scientists are working in informal collaborations to solve complex problems that require multiple types of skills. Such networks generally might consist of participants with complementary or similar skills, who might decide to collaborate to solve more efficiently a single large problem. We argue that, given the diverse skills that such collaborations involve, deciding which partners to cooperate with is both critical and difficult. Two particularly important factors in this process are trust and reputation.

text: Trust and reputation in dynamic scientific communities The formation of collaboration networks (or communities) is an important latent effect in many computational science undertakings. Generally, collaboration networks bring together participants who wish to achieve some common goal or outcome (often over short time frames). Increasingly, scientific collaborations are becoming interdisciplinary, and scientists are working in informal collaborations to solve complex problems that require multiple types of skills. Such networks generally might consist of participants with complementary or similar skills, who might decide to collaborate to solve more efficiently a single large problem. We argue that, given the diverse skills that such collaborations involve, deciding which partners to cooperate with is both critical and difficult. Two particularly important factors in this process are trust and reputation.

year: 2004

title: Mobile app development: Work-integrated learning collaborations with Māori and Fijian partners

authors: Yeo, Alvin

subjects: computer science

abstract: Only a few information and communication technology (ICT) work-integrated learning (WIL) projects involving universities and Indigenous partners are being reported and very little is known about the approaches that are followed. This article reports on successful student work placements in Indigenous communities when codeveloping software for the community. We provide two case studies of projects which involved work-integrated learning students and researchers from a university, as well as researchers and practitioners from Indigenous communities in New Zealand and Fiji. Two independent app development projects were the central focus of the collaborations with these two communities including placement students. The article describes the learning and insights from these WIL projects and provides recommendations for creating successful WIL opportunities with Indigenous communities.

text: Mobile app development: Work-integrated learning collaborations with Māori and Fijian partners Only a few information and communication technology (ICT) work-integrated learning (WIL) projects involving universities and Indigenous partners are being reported and very little is known about the approaches that are followed. This article reports on successful student work placements in Indigenous communities when codeveloping software for the community. We provide two case studies of projects which involved work-integrated learning students and researchers from a university, as well as researchers and practitioners from Indigenous communities in New Zealand and Fiji. Two independent app development projects were the central focus of the collaborations with these two communities including placement students. The article describes the learning and insights from these WIL projects and provides recommendations for creating successful WIL opportunities with Indigenous communities.

year: 2022