2,130 research outputs found
Fungal phoenix rising from the ashes?
During May 2010, sporocarps of what appeared to be an Armillaria sp. were found in large clumps in historic Kirstenbosch Botanical Gardens on the foot of Table Mountain, Cape Town, South Africa. These sporocarps could be physically linked to the roots of unidentified dead trees and Protea spp. The aim of this study was to identify the Armillaria sp. found fruiting in Kirstenbosch. To achieve this goal isolates were made from the mycelium under the bark of dead roots linked to sporocarps. The ITS and IGS-1 regions were sequenced and compared to sequences of Armillaria spp. available on GenBank. Cladograms were generated using ITS sequences to determine the phylogenetic relationship of the isolates with other Armillaria spp. Sequence comparisons and phylogenetic analyses showed that the isolates represented A. mellea. They were also identical to isolates of this species previously discovered in the Company Gardens in South Africa and introduced from Europe apparently by the early Dutch Settlers. Armillaria mellea is alien and apparently invasive in Cape Town, fruits profusely and has the potential to spread to sensitive native forests on the foothills of the City
Low carbon housing: lessons from Elm Tree Mews
This report sets out the findings from a low carbon housing trial at Elm Tree Mews, York, and discusses the technical and policy issues that arise from it. The Government has set an ambitious target for all new housing to be zero carbon by 2016. With the application of good insulation, improved efficiencies and renewable energy, this is theoretically possible. However, there is growing concern that, in practice, even existing carbon standards are not being achieved and that this performance gap has the potential to undermine zero carbon housing policy. The report seeks to address these concerns through the detailed evaluation of a low carbon development at Elm Tree Mews. The report: * evaluates the energy/carbon performance of the dwellings prior to occupation and in use; * analyses the procurement, design and construction processes that give rise to the performance achieved; * explores the resident experience; * draws out lessons for the development of zero carbon housing and the implications for government policy; and * proposes a programme for change, designed to close the performance gap
Airtightness of buildings — towards higher performance: Final Report — Domestic Sector Airtightness
This report constitutes milestone D11 — Final Report — Domestic Sector Airtightness of the Communities and Local Government/ODPM Project reference CI 61/6/16 (BD2429) Airtightness of Buildings — Towards Higher Performance (Borland and Bell, 2003). This report presents the overall conclusions and key messages obtained from the project through design assessments, construction observations, discussions with developers and pressurisation test results. It also summarises discussion on the airtight performance of current UK housing, the implementation and impact of current and future legislation, and identifies potential areas for future work
Evaluating the impact of an enhanced energy performance standard on load-bearing masonry domestic construction: Understanding the gap between designed and real performance: lessons from Stamford Brook.
This report is aimed at those with interests in the procurement, design and construction of new dwellings both now and in the coming years as the Government’s increasingly stringent targets for low and zero carbon housing approach. It conveys the results of a research project, carried out between 2001 and 2008, that was designed to evaluate the extent to which low carbon housing standards can be achieved in the context of a large commercial housing development. The research was led by Leeds Metropolitan University in collaboration with University College London and was based on the Stamford Brook development in Altrincham, Cheshire. The project partners were the National Trust, Redrow and Taylor Wimpey and some 60 percent of the planned 700 dwelling development has been completed up to June 2008. As the UK house building industry and its suppliers grapple with the challenges of achieving zero carbon housing by 2016, the lessons arising from this project are timely and of considerable value. Stamford Brook has demonstrated that designing masonry dwellings to achieve an enhanced energy standard is feasible and that a number of innovative approaches, particularly in the area of airtightness, can be successful. The dwellings, as built, exceed the Building Regulations requirements in force at the time but tests on the completed dwellings and longer term monitoring of performance has shown that, overall, energy consumption and carbon emissions, under standard occupancy, are around 20 to 25 percent higher than design predictions. In the case of heat loss, the discrepancy can be much higher. The report contains much evidence of considerable potential but points out that realising the design potential requires a fundamental reappraisal of processes within the industry from design and construction to the relationship with its supply chain and the development of the workforce. The researchers conclude that, even when builders try hard, current mainstream technical and organisational practices together with industry cultures present barriers to consistent delivery of low and zero carbon performance. They suggest that the underlying reasons for this are deeply embedded at all levels of the house building industry. They point out also that without fundamental change in processes and cultures, technological innovations, whether they be based on traditional construction or modern methods are unlikely to reach their full potential. The report sets out a series of wide ranging implications for new housing in the UK, which are given in Chapter 14 and concludes by firmly declaring that cooperation between government, developers, supply chains, educators and researchers will be crucial to improvement. The recommendations in this report are already being put into practice by the researchers at Leeds Metropolitan University and University College London in their teaching and in further research projects. The implications of the work have been discussed across the industry at a series of workshops undertaken in 2008 as part of the LowCarb4Real project (see http://www.leedsmet.ac.uk/as/cebe/projects/lowcarb4real/index.htm). In addition, the learning is having an impact on the work of the developers (Redrow and Taylor Wimpey) who, with remarkable foresight and enthusiasm, hosted the project. This report seeks to make the findings more widely available and is offered for consideration by everyone who has a part to play in making low and zero carbon housing a reality
Celoporthe dispersa gen. et sp. nov. from native Myrtales in South Africa
In a survey for Cryphonectria and Chrysoporthe species on
Myrtales in South Africa, a fungus resembling the stem canker
pathogen Chrysoporthe austroafricana was collected from native
Syzygium cordatum near Tzaneen (Limpopo Province), Heteropyxis
canescens near Lydenburg (Mpumalanga Province) and exotic Tibouchina
granulosa in Durban (KwaZulu-Natal Province). The fungus was associated
with dying branches and stems on S. cordatum, H.
canescens and T. granulosa. However, morphological
differences were detected between the unknown fungus from these three hosts
and known species of Chrysoporthe. The aim of this study was to
characterise the fungus using DNA sequence comparisons and morphological
features. Pathogenicity tests were also conducted to assess its virulence on
Eucalyptus (ZG 14 clones), H. natalensis and T.
granulosa. Plants of H. canescens were not available for
inoculation. Results showed distinct morphological differences between the
unknown fungus and Chrysoporthe spp. Phylogenetic analysis showed
that isolates reside in a clade separate from Chrysoporthe and other
related genera. Celoporthe dispersa gen. et sp. nov. is, therefore,
described to accommodate this fungus. Pathogenicity tests showed that
C. dispersa is not pathogenic to H.
natalensis, but that it is a potential pathogen of
Eucalyptus and Tibouchina spp
A disease epidemic on Zizyphus mucronata in the Kruger National Park caused by Coniodictyum chevalieri
This study records a severe outbreak of a disease on Zizyphus
mucronata (Rhamnaceae) in Greater Kruger National Park, South
Africa. The causal agent of the disease was found to be Coniodictyum
chevalieri, a fungus previously believed to be very rare. Detailed
illustrations of the symptoms and fungus are presented in order to facilitate
future studies. The known geographical distribution of Coniodictyum
is presented in relation to the distribution of its host, and a short review
of its systematic history is also given. This also treats an invalidly
published species name in South Africa, which has confused the literature. A
DNA-based phylogeny is presented for the pathogen and this reflects the unique
nature of its geographical distribution and biology
Multi-gene phylogenies and phenotypic characters distinguish two species within the Colletogloeopsis zuluensis complex associated with Eucalyptus stem cankers
Colletogloeopsis zuluensis, previously known as Coniothyrium
zuluense, causes a serious stem canker disease on Eucalyptus
spp. grown as non-natives in many tropical and sub-tropical countries. This
stem canker disease was first reported from South Africa and it has
subsequently been found on various species and hybrids of Eucalyptus
in other African countries as well as in countries of South America and
South-East Asia. In previous studies, phylogenetic analyses based on DNA
sequence data of the ITS region suggested that all material of C.
zuluensis was monophyletic. However, the occurrence of the fungus in a
greater number of countries, and analyses of DNA sequences with additional
isolates has challenged the notion that a single species is involved with
Coniothyrium canker. The aim of this study was to consider the phylogenetic
relationships amongst C. zuluensis isolates from all available
locations and to support these analyses with phenotypic and morphological
comparisons. Individual and combined phylogenies were constructed using DNA
sequences from the ITS region, exons 3 through 6 of the β-tubulin gene,
the intron of the translation elongation factor 1-α gene, and a partial
sequence of the mitochondrial ATPase 6 gene. Both phylogenetic data and
morphological characteristics showed clearly that isolates of C.
zuluensis represent at least two taxa. One of these is C.
zuluensis as it was originally described from South Africa, and we
provide an epitype for it. The second species occurs in Argentina and Uruguay,
and is newly described as C. gauchensis. Both fungi are serious
pathogens resulting in identical symptoms. Recognising them as different
species has important quarantine consequences
Multi-gene phylogenies define Ceratocystiopsis and Grosmannia distinct from Ophiostoma
Ophiostoma species have diverse morphological features and are
found in a large variety of ecological niches. Many different classification
schemes have been applied to these fungi in the past based on teleomorph and
anamorph features. More recently, studies based on DNA sequence comparisions
have shown that Ophiostoma consists of different phylogenetic groups,
but the data have not been sufficient to define clear monophyletic lineages
represented by practical taxonomic units. We used DNA sequence data from
combined partial nuclear LSU and β-tubulin genes to consider the
phylogenetic relationships of 50 Ophiostoma species, representing all
the major morphological groups in the genus. Our data showed three
well-supported, monophyletic lineages in Ophiostoma. Species with
Leptographium anamorphs grouped together and to accommodate these
species the teleomorph-genus Grosmannia (type species G.
penicillata), including 27 species and 24 new combinations, is
re-instated. Another well-defined lineage includes species that are
cycloheximide-sensitive with short perithecial necks, falcate ascospores and
Hyalorhinocladiella anamorphs. For these species, the
teleomorph-genus Ceratocystiopsis (type species O. minuta),
including 11 species and three new combinations, is re-instated. A third group
of species with either Sporothrix or Pesotum anamorphs
includes species from various ecological niches such as Protea
infructescences in South Africa. This group also includes O.
piliferum, the type species of Ophiostoma, and these species are
retained in that genus. Ophiostoma is redefined to reflect the
changes resulting from new combinations in Grosmannia and
Ceratocystiopsis. Our data have revealed additional lineages in
Ophiostoma linked to morphological characters. However, these species
are retained in Ophiostoma until further data for a larger number of
species can be obtained to confirm monophyly of the apparent lineages
A multi-gene phylogeny for species of Mycosphaerella occurring on Eucalyptus leaves
Species of the ascomycete genus Mycosphaerella are regarded as
some of the most destructive leaf pathogens of a large number of economically
important crop plants. Amongst these, approximately 60 Mycosphaerella
spp. have been identified from various Eucalyptus spp. where they
cause leaf diseases collectively known as Mycosphaerella Leaf Disease (MLD).
Species concepts for this group of fungi remain confused, and hence their
species identification is notoriously difficult. Thus, the introduction of DNA
sequence comparisons has become the definitive characteristic used to
distinguish species of Mycosphaerella. Sequences of the Internal
Transcribed Spacer (ITS) region of the ribosomal RNA operon have most commonly
been used to consider species boundaries in Mycosphaerella. However,
sequences for this gene region do not always provide sufficient resolution for
cryptic taxa. The aim of this study was, therefore, to use DNA sequences for
three loci, ITS, Elongation factor 1-alpha (EF-1α) and Actin (ACT) to
reconsider species boundaries for Mycosphaerella spp. from
Eucalyptus. A further aim was to study the anamorph concepts and
resolve the deeper nodes of Mycosphaerella, for which part of the
Large Subunit (LSU) of the nuclear rRNA operon was sequenced. The ITS and
EF-1α gene regions were found to be useful, but the ACT gene region did
not provide species-level resolution in Mycosphaerella. A phylogeny
of the combined DNA datasets showed that species of Mycosphaerella
from Eucalyptus cluster in two distinct groups, which might
ultimately represent discrete genera
Microthia, Holocryphia and Ursicollum, three new genera on Eucalyptus and Coccoloba for fungi previously known as Cryphonectria
Cryphonectria havanensis is a fungus associated with
Eucalyptus species in Cuba and Florida (U.S.A.). Until recently,
there have been no living cultures of C. havanensis and it has thus
not been possible to assess its taxonomic status. Isolates thought to
represent this fungus have, however, emerged from surveys of
Eucalyptus in Mexico and Hawaii (U.S.A.). Results of this study
showed that these isolates represent C. havanensis but reside in a
genus distinct from Cryphonectria sensu stricto, which is described
here as Microthia. Isolates of an unidentified fungus occurring on
Myrica faya in the Azores and Madeira also grouped in
Microthia and were identical to other M. havanensis
isolates. Cryphonectria coccolobae, a fungus occurring on sea grape
(Coccoloba uvifera) in Bermuda and Florida, was found to be
morphologically identical to Microthia and is transferred to this
genus, but as a distinct species. Surveys for M. coccolobae on sea
grape in Florida, yielded a second diaporthalean fungus from this host. This
fungus is morphologically and phylogenetically distinct from M.
coccolobae and other closely related taxa and is described as
Ursicollum fallax gen. et sp. nov. Phylogenetic analyses in this
study have also shown that isolates of C. eucalypti, a pathogen of
Eucalyptus in South Africa and Australia, group in a clade separate
from all other groups including that representing Cryphonectria sensu
stricto. This difference is supported by the fact that Cryphonectria
eucalypti has ascospore septation different to that of all other
Cryphonectria species. A new genus, Holocryphia, is thus
erected for C. eucalypti
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