Armillaria species are important root rot pathogens with a wide host range and a worldwide distribution. The taxonomy of these fungi has been problematic for many years but the understanding of the relationships between them has been substantially improved through the application of DNA sequence comparisons. In this study, relationships between different Armillaria species were determined using elongation factor 1-alpha DNA sequence data for the first time. A total of 42 isolates, representing the majority of Armillaria species, with diverse geographic distributions and hosts, were included in this study. PCR amplification yielded products of 600 bp for all the isolates. Phylogenetic trees resulting from parsimony analysis showed that this gene region is useful for studying relationships between species. Generally, results were similar to those emerging from previous comparisons using ITS and IGS-1 sequence data. Phylogenetic trees generated from the dataset grouped the African taxa in a strongly supported clade, basal to the rest of the Armillaria species included in the study. The Armillaria species originating from the Northern Hemisphere formed a monophyletic group. Within this group, isolates of A. mellea constituted four subclades, representing their geographical origin. The phylogenetic relationships among species from the Southern Hemisphere were not entirely resolved. However, A. pallidula, A. fumosa and A. hinnulea grouped in a strongly supported clade and isolates of A. limonea formed a sister clade with those of A. luteobubalina. This is the first time a single-copy protein coding gene has been used to study phylogenetic relationships in Armillaria, and overall the data support previously held views regarding the relationships between species.

Variations in cultural and biochemical characteristics have been used to group 20 Armillaria isolates collected from different hosts and regions in Zimbabwe. Morphological features, including colony type and rhizomorph characteristics in vitro, rhizomorph characteristics from inoculum buried in soil, and features of basidiocarps produced in vitro on wood, millet and oranges, divided the Zimbabwean isolates into three morphologically distinct groups, designated I, II and III. Biochemical attributes involving isozyme and protein patterns studied by electrophoresis and isoelectric focusing also indicated three groups which corresponded precisely with the three groups observed for morphological studies. Isozyme analyses of pectin lyase (PL), pectin methylesterase (PME), beta‐1,3‐glucanase, nonspecific esterases and putative suberinases were important in grouping the isolates. Pectin lyase and pectin methylesterase patterns gave the clearest and mostly easily interpreted results. Total protein patterns by SDS–polyacrylamide gel electrophoresis also showed some group‐specific bands. Cluster and principal component analyses of the data confirmed the separation of the Zimbabwean Armillaria isolates into three distinct groups.

Modeling the interaction of Tuberculosis (TB) and AIDS (HIV) drugs in the treatment of the TB/HIV co-infection shows that the treatment of Mtb (Mycobacterium tuberculosis) and AIDS improves. The administration of HIV drugs without TB drugs during co-infection favors the treatment of HIV, but the patient will eventually die of the Mtb opportunistic infection. Reducing the interaction of TB and HIV drugs and increasing the performance (efficiency of inhibition) of Reverse Transcriptase Inhibitors (RTIs) in CD4+ T cells improves the treatment of HIV and leads to the preferential replication of HIV particles in macrophages. The simultaneous administration of TB and HIV drugs is to be recommended for it prevents patients from dying of the Mtb opportunistic infection.AIDS, co-infection, highly active anti-retroviral therapy (HAART), Mycobacterium tuberculosis, TB chemotherapy,

Armillaria species are amongst the most important pathogens of trees and have a world-wide distribution. In recent years, the taxonomy of Northern Hemisphere Armillaria spp. has been extensively treated, but those occurring in Africa are poorly known. Previously, isolates of Armillaria from Zimbabwe have been grouped based on morphology and biochemical tests. In this study, six isolates representing the three previously characterized groups of Armillaria spp. occurring in Zimbabwe were analysed using DNA-based techniques. Three distinct clusters emerged from both PCR-RFLP and analysis of sequence data for the IGS-1 rRNA operon. The three groups corresponded to those previously identified based on morphology and biochemical tests. Differences in IGS-1 sequences strongly suggest that the Zimbabwean groups represent three distinct taxa. Isolates belonging to Group I, previously assumed to be to A. heimii, were similar to those identified as A. fuscipes from South Africa and La Reunion. Group II isolates resided in a clade apart from all other isolates and appear to represent A. heimii. The remaining isolates residing in Group III clustered with isolates from Zambia and Cameroon. These are different from A. heimii and A. fuscipes and apparently represent an undescribed taxon.

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