14 research outputs found
Spoligotyping and Drug Resistance Analysis of Mycobacterium tuberculosis Strains from National Survey in China
BACKGROUND: Tuberculosis (TB), caused by Mycobacterium tuberculosis complex (MTBC), is one of the major causes of death in the world today. Although China has the second largest global case rate of tuberculosis, a systematic study of TB prevalence in China has not been completed. From 2006 to 2007, the base line surveillance of tuberculosis was carried out by Ministry of Health, and more than 4000 representative strains were selected from 31 provinces in China. METHODOLOGY/PRINCIPAL FINDINGS: The aim of the present research was to survey the genotypes of representative Mycobacterium tuberculosis (M. tuberculosis) strains from China using spacer oligonucleotide typing (spoligotyping), and to analyze the relationship between genotype and drug resistance for the first time. A total of 4017 clinical isolates were collected from 2007 to 2008 throughout China. Among those M. tuberculosis isolates, 2500 (62.2%) isolates were Beijing genotypes. The percentage of Beijing genotypes in northern China was higher than in southern China (76.5% vs. 53.2%). Additionally, the frequencies of rifampin-resistant, ofloxacin-resistant and multidrug-resistant isolates were significantly higher in Beijing genotype strains than non-Beijing strains. Furthermore, a novel genotype named "China Southern genotype (CS)" was only isolated from Fujian and Guangdong provinces. Hence, it is very practical to uncover the reason for prevalence of the CS type in southern China. CONCLUSIONS/SIGNIFICANCE: In conclusion, Beijing family genotypes were still the predominant genotype throughout China, which exhibited a greater correlation with rifampin-resistance, ofloxacin-resistance and MDR phenotypes than other TB spoligotypes, and some regions of China showed several unique characters in the distribution of M. tuberculosis genotypes. Our research represents an important contribution for the TB control and research community, which completes broad pictures on drug resistance levels and distribution of M. tuberculosis strain types over China
Pathways towards coexistence with large carnivores in production systems
Coexistence between livestock grazing and carnivores in rangelands is a major challenge in terms of sustainable agriculture, animal welfare, species conservation and ecosystem function. Many effective non-lethal tools exist to protect livestock from predation, yet their adoption remains limited. Using a social-ecological transformations framework, we present two qualitative models that depict transformative change in rangelands grazing. Developed through participatory processes with stakeholders from South Africa and the United States of America, the models articulate drivers of change and the essential pathways to transition from routine lethal management of carnivores towards mutually beneficial coexistence. The pathways define broad actions that incorporate multiple values in grazing systems including changes to livestock management practices, financial support, industry capacity building, research, improved governance and marketing initiatives. A key fnding is the new concept of ‘Predator Smart Farming’, a holistic and conscientious approach to agriculture, which increases the resilience of landscapes, animals (domesticated and wild) and rural livelihoods. Implementation of these multiple pathways would lead to a future system that ensures thriving agricultural communities, secure livelihoods, reduced violence toward animals, and landscapes that are productive and support species conservation and coexistence
Delineating fine-scale genetic units in amphibians: probing the primacy of ponds
The population structure of pond-breeding amphibians is shaped by their distinct breeding foci, but it is
unclear to what extent this is reflected in the fine-scale distribution of genetic diversity. We used microsatellite
genotypes to investigate the genetic signatures of 24 populations of European newts, Triturus
cristatus and T. marmoratus, inhabiting 21 ponds in a confined study area (7.5 · 3.5 km) in western France.
Employing a Bayesian clustering approach based on individual genotypes that minimises departures from
Hardy–Weinberg equilibrium and linkage disequilibrium, no evidence was found for within-pond substructuring.
Subjecting all sampled ponds simultaneously to this procedure revealed a clear signal of
partitioning, with the most likely number of clusters however below the actual number of ponds (seven in T.
cristatus, three in T. marmoratus). A more hierarchical Bayesian approach, with pond as analysis unit, was
achieved to separate ponds from genetically more meaningful units, and reduced the T. cristatus populations
to 11 clusters, and the T. marmoratus populations to five clusters. We were unable to specify a
minimum nearest-neighbour distance where ponds are separate units, probably due to both historical and
current demographic processes. The implications for strategies to manage and conserve endangered
amphibians in human-altered landscapes are discussed
Homothallism: an umbrella term for describing diverse sexual behaviours
Sexual reproduction is notoriously complex in fungi with species able to produce sexual progeny
by utilizing a variety of different mechanisms. This is even more so for species employing multiple sexual
strategies, which is a surprisingly common occurrence. While heterothallism is relatively well understood in
terms of its physiological and molecular underpinnings, homothallism remains greatly understudied. This can be
attributed to it involving numerous genetically distinct mechanisms that all result in self-fertility; including primary
homothallism, pseudohomothallism, mating type switching, and unisexual reproduction. This review highlights
the need to classify these homothallic mechanisms based on their molecular determinants and illustrates what is
currently known about the multifaceted behaviours associated with homothallism.The University of Pretoria, the Department
of Science and Technology (DST)/National Research Foundation
(NRF) Centre of Excellence in Tree Health Biotechnology and the
Genomics Research Institute (University of Pretoria Institutional
Research Theme) as well grants from the National Research Foundation
of South Africa (including Grant specific unique reference number
(UID) 83924).http://www.imafungus.orgam201