Identification of the gene encoding DNA topoisomerase I from Candida albicans

Abstract A gene encoding a type I topoisomerase (TOP1) was isolated from Candida albicans , sequenced, and expressed in Saccharomyces cerevisiae . The TOP1 gene was identified from a C. albicans genomic library by hybridization with the product of a polymerase chain reaction with degenerate primer sets encoding regions conserved in other TOP1 genes. A clone containing an open reading frame of 2463 bp and predicted to encode a protein of 778 amino acids with sequence similarity to eukaryotic type I topoisomerases was identified. The C. albicans TOP1 gene restored camptothecin sensitivity and increased the topoisomerase activity in S. cerevisiae , indicating that the DNA fragment encodes a functional C. albicans topoisomerase I.     

Comparison of fire patterns and fire frequency in two tropical savanna bioregions

Abstract Fire is a signi?cant determinant of vegetation structure in Australia’s savannas and has been implicated in the decline of many species. Identifying the patterns of ?re in the landscape is fundamental to understanding vegetation dynamics but variation over time and space makes generalization dif?cult and speci?c management recommendations elusive. In order to improve the knowledge base for ?re management in tropical savannas, we investigated interregional variation in ?re patterns in two Queensland bioregions, the Mount Isa Inlier (MII) and Cape York Peninsula (CYP), over a 5‐year period (1999–2003). Remotely sensed satellite data were used to identify burnt areas on a monthly basis for the western half of the CYP bioregion and about two‐thirds of the smaller MII. Fire scars were mapped from JPEG‐compressed, low‐resolution Landsat images using geographical information system technology and data were investigated to determine annual burning patterns. Patterns were interpreted with regard to meteorological information and recent ?re history. The area burnt per annum on western CYP was generally an order of magnitude greater than the area burnt on the MII. In the biggest ?re year, nearly 74% (5 295 098 ha) of the CYP landscape burnt, compared with 35% (1 770 771 ha) of the MII landscape. The minimum percentage of the CYP study area burnt in 1 year between 1999 and 2003 was 43.1%, compared with 1.6% for the MII. The reliability and amount of seasonal rainfall was a strong determinant of differences in time of ?re occurrence and area burnt between regions. Widespread wild?res were signi?cantly related to above average rainfall in the preceding 12 months in the Mt. Isa area but not in CYP. Rainfall also affected ?re frequency. Predictable wet season rainfall on CYP allowed for a biennial ?re return interval, while on the semiarid MII, the average ?re return interval was 5 years or longer. We conclude that the ?re patterns in the semiarid MII are similar to those reported for arid Australia, while ?re patterns in western CYP are comparable with other mesic savanna areas.     

Behavioural sequence in the attraction of the bark beetle Ips typographus to pheromone sources

ABSTRACT. The functions of the two synergistic pheromone components, (4S)- cis -verbenol (cV) and 2-methyl-3-buten-2-01 (MB), and the role of ipsdienol in the attraction of Ips typographus (L.) (Scolytidae) to pheromone sources were studied in the field. Absolute and relative beetle catches were compared between several traps placed at and nearby a central pheromone source: a pipe trap containing the source, a surrounding sticky trap, a nearby window trap, and four distant window traps. A higher catch in the outer down-wind distant traps indicated an up-wind anemotaxis to the source. Increased MB release, with cV constant, increased the proportion caught in the central pipe trap, indicating MB as a landing stimulus. Release of MB alone gave a very small catch. Ipsdienol could not substitute for cV in the synergism with MB. An increase of cV, with MB constant, increased the number of beetles caught, but not the proportion caught in the pipe trap. The sex ratio was equal in the window traps, but fell to 30% males in both sticky and pipe traps, showing that a large proportion of the males attracted to the source did not land. The proportion of males in the pipe trap was reduced at the highest cV dose. The results support the idea of each pheromone component having a different relative importance in releasing different steps in the behavioural chain.     

HUMF13A01 in autochthonous Basques and in genetically related populations

A population gentics study was carried out on 678 Basque individuals using the short tandem repeat HUMF13A01. Thirteen different alleles were detected. This population is in Hardy-Weinberg equilibrium. The singularity of the Basque population’s HUMF13A01 allele frequencies is displayed in the European context, through some genetic similarities are shown, especially with some neighbouring and culturally related populations, and with other populations with which Basques may have shared ancient common roots, such as the Sardinians.     

Assessing the climate change effects on the distribution pattern of the Azerbaijan Mountain Newt (Neurergus crocatus)

Climate change is a grave danger for humans and a looming threat to Earth's biodiversity in the twenty-first century. Assessing the vulnerability of species to climate change is critical for practical conservation efforts. Due to their limited dispersal ability, amphibians are one of the most vulnerable groups of vertebrates to climate change. Among them, the species that inhabit mountains suffer a tremendous amount of climate change-induced pressures. We, therefore, adopted the Azerbaijan Mountain Newt (Neurergus crocatus), which currently inhabits Northwest Iran, North Iraq, and Southeast Turkey, as a case study for assessing the effects of climate change on the distribution patterns of mountain amphibians. By applying the species distribution models (SDMs) in this study, we tried to hindcast the species distribution area in the past and illustrate the impacts of climate change on its distribution in the present and future (the 2050s and 2070s) climate conditions. Also, the patch metrics have been deployed for identifying habitat fragmentation. Our results indicate a more than 50% rise in the species’ current suitable habitats compared to its glacial refugia. The suitable habitat is expected to gradually decrease in RCP 2.6 and RCP 8.5. Among the three countries in which the species occurs, its distribution overlaps with protected areas only in Iraq. The number of habitat patches will grow and reach approximately 20 to 60 patches by 2070 and the average area of the patches will decrease throughout this time. Aside from the numerous threats that endanger the species, climate change puts the long-term existence of Azerbaijan Newt in jeopardy. The results of this study stress the urgent need for taking extreme measures on the species management and conserving its remnant habitat patches.