A comprehensive multigene phylogeny of Phylloporia (Hymenochaetaceae, Basidiomycota), with an emphasis on tropical African species.

Scutellaria is a large, subcosmopolitan genus of around 360 species (Paton 1990). There are 8 species in Africa; the 4 tropical species are dealt with in this paper. Three species have a North African/Mediterranean distribution: S. orientalis L. is found in the mountains of Morocco, S. columnae All. in Algeria and S. rubicunda Hornem. sens. lat. in Libya. S. racemosa Pers., originally from temperate S. America, is naturalized in South Africa. The aim of this paper is to provide a key to and describe the four tropical African species. The tropical African species of Scutellaria were previously revised by Baker (1990), who recognized 6 species. Four of these, S. schweinfurthii Briq., S. paucifolia Baker, S. livingstonei Baker and S. debeerstii Briq. differ only in leaf morphology. When developmental variation is taken into account, these differences no longer merit specific recognition and therefore only one species, S. schweinfurthii, is recognized. Forms with long, narrowly ovate or linear leaves, referable to the type of S. schweinfurthii, occur only in Ethiopia, S Sudan and NW Uganda. Specimens from further south or west tend to have smaller, broader leaves. Two subspecies are therefore recognized, subsp. schweinfurthii and subsp. paucifolia (Baker) Paton (see Map 1). Of the tropical African species, S. violascens Giirke, S. polyadena Briq. and S. schweinfurthii Briq., with glabrous nutlets, internal pericarp glands and no pericarp air spaces, belong to the 'S. violascens' species-group defined in Paton (1990). The remaining species, S. arabica, belongs in the 'S. albida' species-group. This species has hairs on the nutlet papillae, lacks internal pericarp glands and has pericarp air spaces.

Marine durability of heartwoods obtained from tropical African and European species against marine borer attacks in underwater exposure in Turkish coasts was investigated. Test hangers including wood species of 18 European and 15 African wood species were fastened to test area and exposed at a depth of 6 m along the coasts of seas (East and West Black Sea, Marmara Sea, Aegean, East and West coasts of mediterranean in Turkey seashore). Most European wood samples suffered severe attacks from boring organisms. On the other hand, some tropical African species (Lophira alata, Nauclea diderichii, Tieghemella heckelii, Chlorophora excelsa, Distemonanthus benthamianus, Pterocarpus soyauxii and Millettia laurentii) showed high natural marine durability in all seas, while the rest of them were only

Requirement of the carboxy-terminal domain of RNA polymerase II for the transcriptional activation of chromosomal c-fos and hsp70A genes

As the first step in the analysis of the transcription process in the African trypanosome, Trypanosoma brucei, we have started to characterise the trypanosomal RNA polymerases. We have previously described the gene encoding the largest subunit of RNA polymerase II and found that two almost identical RNA polymerase II genes are encoded within the genome of T. brucei. Here we present the identification, cloning and sequence analysis of the gene encoding the largest subunit of RNA polymerase III. This gene contains a single open reading frame encoding a polypeptide with a Mr of 170 kD. In total, eight encoding a polypeptide with a Mr of 170 kD. In total, eight highly conserved regions with significant homology to those previously reported in other eukaryotic RNA polymerase largest subunits were identified. Some of these domains contain functional sites, which are conserved among all eukaryotic largest subunit genes analysed thus far. Since these domains make up a large part of each polypeptide, independent of the RNA polymerase class, these data strongly support the hypothesis that these domains provide a major part of the transcription machinery of the RNA polymerase complex. The additional domains which are uniquely present in the largest subunit of RNA polymerase I and II, respectively, two large hydrophylic insertions and a C-terminal extension, might be a determining factor in specific transcription of the gene classes.

The gross morphology of the pollen of all southern African species and subspecies of Justicia and Siphonoglossa was investigated, as well as that of eight tropical African species of Justicia. The following pollen types were found in the southern African species of Justicia: two- or three-colporate, each with the margocolpus either entire or broken up into areolae, and two-porate areolate pollen. One tropical African species had the colpus very short, and in another tropical African species it was replaced by an extra row of areolae. All Siphonoglossa species had two-colporate pollen with areolae and long colpi. The southern African species of Justicia could be separated from Siphonoglossa on pollen characters, and some sections of Justicia could also be distinguished on the same basis.

New material of a species initially thought to be undescribed appears to match the description of the previously published species, Stachys nemorivaga Briq. This neglected species came to light when the two authors were revising Stachys for Flora Zambesiaca and Flora of Tropical East Africa, and looking at Stachys for the Flora of Ethiopia. Stachys nemorivaga was previously known only from the holotype (from material collected in Angola) which was destroyed in Berlin during the Second World War. It has subsequently been collected in Zambia and Zaire as well as a further collection in Angola. Stachys is a large sub-cosmopolitan genus in the Labiatae, subfamily Lamioideae (Cantino et al. 1992) which includes about 450 species (Codd 1985). The genus is mostly centred in the Mediterranean region of Europe and Turkey, although about 80 species (Epling 1934) occur in N. and S. America (32 of which are confined to N. America (Mulligan & Munro 1989). In Africa over 40 species occur in South Africa (Codd 1985), over 20 species in north Africa, 10 species in northeast tropical Africa, 8 species in south tropical Africa, 6 species in east tropical Africa, 3 species in west tropical Africa and 2 species in the Congolian region (one of which is S. nemorivaga). A number of species within the genus are widely cultivated for agricultural (Chinese Artichoke-S. affinis L.), horticultural (S. coccinea (L.) Trev., S. germanica L., S. byzantinia C. Koch. and others) and medicinal purposes (S. officinalis (L.) Trev. used in Europe, and S. cuneata Banks ex Benth. and S. linearis Burch. ex Benth. in South Africa (Codd 1985) to name but a few). Briquet (1894) placed Stachys nemorivaga in sect. Stachys [Stachyotypus) Dum.] subsect. Ruderales Benth. and then in 1896 placed it in sect. Stachys [Eustachys Briq. ] subsect. Rectae Boiss. Although Bhattercharjee (1980), proposed an infrageneric classification of Stachys, she did not consider the tropical African species in detail. In tropical Africa the native species fall within three groups (Sebsebe and Harley 1992), section Stachys, section Ambleia Benth. and a further new section which will be considered by Sebsebe & Harley in a subsequent paper. The different sections are distinguished by a different combination of trichome types and each of the sections occupy a different phytogeographical region. Section

Microsporidia Evolved from Ancestral Sexual Fungi

Genomic sequences for the large subunit of human RNA polymerase II corresponding to a part of the fifth exon were inserted into an expression vector at the carboxy-terminal end of the beta-galactosidase gene. The in-frame construct produced a 125-kilodalton fusion protein, containing approximately 10 kilodaltons of the large subunit of RNA polymerase II and 116 kilodaltons of beta-galactosidase. The purified bacterially produced fusion protein inhibited specific transcription from the adenovirus type 2 major late promoter, while beta-galactosidase had no effect. This effect of the fusion protein was during RNA elongation, not at the level of initiation, resembling the faithfully initiated but incomplete transcripts produced with purified factors in the absence of SII. Similarly, monoclonal antibody 2-7B, which reacts with the RNA polymerase II region represented in the fusion protein, inhibited specific transcription at the level of elongation in a whole-cell extract. Both monoclonal antibody 2-7B and the fusion protein, although unable to inhibit purified RNA polymerase II in a nonspecific transcription assay, selectively blocked the stimulation elicited by transcription elongation factor SII on the activity of the purified enzyme in vitro. This suggests that the fusion protein traps the SII in nonstimulatory interactions and that antibody 2-7B inhibits SII binding to RNA polymerase II. Thus, this suggests that an SII-binding contact required for specific RNA elongation resides within the fifth exon region of the largest RNA polymerase II subunit.

Genomic sequences for the large subunit of human RNA polymerase II corresponding to a part of the fifth exon were inserted into an expression vector at the carboxy-terminal end of the beta-galactosidase gene. The in-frame construct produced a 125-kilodalton fusion protein, containing approximately 10 kilodaltons of the large subunit of RNA polymerase II and 116 kilodaltons of beta-galactosidase. The purified bacterially produced fusion protein inhibited specific transcription from the adenovirus type 2 major late promoter, while beta-galactosidase had no effect. This effect of the fusion protein was during RNA elongation, not at the level of initiation, resembling the faithfully initiated but incomplete transcripts produced with purified factors in the absence of SII. Similarly, monoclonal antibody 2-7B, which reacts with the RNA polymerase II region represented in the fusion protein, inhibited specific transcription at the level of elongation in a whole-cell extract. Both monoclonal antibody 2-7B and the fusion protein, although unable to inhibit purified RNA polymerase II in a nonspecific transcription assay, selectively blocked the stimulation elicited by transcription elongation factor SII on the activity of the purified enzyme in vitro. This suggests that the fusion protein traps the SII in nonstimulatory interactions and that antibody 2-7B inhibits SII binding to RNA polymerase II. Thus, this suggests that an SII-binding contact required for specific RNA elongation resides within the fifth exon region of the largest RNA polymerase II subunit.

The largest subunit of the RNA polymerase II of Trypanosomacruzi lacks the repeats in the carboxy-terminal domain and is encoded by several genes

Genomic and cDNA clones homologous to the RpII215 gene of Drosophila were isolated from Arabidopsis thaliana and assigned to a single copy gene encoding a transcript of 6.8 kb. Nucleotide sequence analysis of Arabidopsis genomic and cDNAs revealed a striking homology to yeast, Caenorhabditis, Drosophila and mouse genes encoding the largest subunit of RNA polymerase II. The Arabidopsis gene rpII215 contains 13 introns, 12 of which interrupt the coding sequence of a protein of 205 kDa. The position of the first intron is conserved between plant and animal genes, while an intron located in the 3' untranslated region of the rpII215 gene is unique to Arabidopsis. Common domains present in all known largest subunits of eucaryotic RNA polymerase II were identified in the predicted sequence of the Arabidopsis RpII215 protein. Both the order and the position of N-terminal Zn2+ finger and of DNA and alpha-amanitin binding motifs are conserved in Arabidopsis. The C-terminal region of the Arabidopsis protein contains 15 consensus and 26 variant YSPTSPS repeats (CTDs). Highly conserved structure among the various C-terminal domains suggests that the largest subunit of RNA polymerase II in plants may also interact with transcription factors and with protein kinases that control the cell cycle as in other organisms.

Mapping and phenotypic analysis of spontaneous isatin-β-thiosemicarbazone resistant mutants of vaccinia virus

The tropical African Laetiporus species are revised, based on morphological, ecological, distribution, and phylogenetic data. Laetiporus discolor, originally described from insular Mauritius, is accepted for the species spanning over the African eastern mountain ranges. Laetiporus oboensis and Laetiporus tenuiculus are described as new from the African equatorial insular São Tomé, based on phylogenetic, morphological, and distribution data. Laetiporus oboensis is characterized by compound basidiomes, with densely imbricated pilei in pale orange tint, a lobed margin, 3–4 pores/mm, and basidiospores averaging 4.8 × 3.7 μm. Laetiporus tenuiculus has mostly solitary, small, thin basidiomes, with pale flesh to pale orange pileus, an incised margin, 4–5 pores/mm, and basidiospores averaging 5.4 × 4.2 µm. A fourth species, known from two isolates from Ethiopian highlands, but for which voucher specimens were not available for description, is uncertain. These four species form an African endemic lineage, whose distribution is Afromountainous.

The alpha-amanitin domain or domain f of the largest subunit of RNA polymerases is one of the most conserved of these enzymes. We have found that the C-terminal part of domain f can be swapped between yeast RNA polymerase II and III. An extensive mutagenesis of domain f of C160, the largest subunit of RNA polymerase III, was carried out to better define its role and understand the mechanism through which C160 participates in transcription. One mutant enzyme, C160-270, showed much reduced transcription of a non-specific template at low DNA concentrations. Abortive synthesis of trinucleotides in a dinucleotide-primed reaction proceeded at roughly wild-type levels, indicating that the mutation did not affect the formation of the first phosphodiester bond, but rather the transition from abortive initiation to processive elongation. In specific transcription assays, on the SUP4 tRNA gene, pausing was extended but the rate of RNA elongation between pause sites was not affected. Finally, the rate of cleavage of nascent RNA transcripts by halted mutant RNA polymerase was increased approximately 10-fold. We propose that the domain f mutation affects the transition between two transcriptional modes, one being adopted during abortive transcription and at pause sites, the other during elongation between pause sites.

We previously purified RNA polymerase II transcription factor delta from rat liver and found that it has an associated DNA-dependent ATPase (dATPase) activity. In this report, we show that delta is also closely associated with a protein kinase activity that catalyzes phosphorylation of the largest subunit of RNA polymerase II. Kinase activity copurifies with transcription and DNA-dependent ATPase (dATPase) activities when delta is analyzed by anion- and cation-exchange HPLC as well as by sucrose gradient sedimentation, arguing that delta possesses all three activities. Phosphorylation of the largest subunits of both rat and yeast RNA polymerase II is stimulated by DNA, whereas phosphorylation of a synthetic peptide containing multiple copies of the carboxyl-terminal heptapeptide repeat is not. Although both ATP and GTP appear to function as phosphate donors, GTP is utilized less than 10% as well as ATP. These findings suggest that delta may exert its action in transcription at least in part through a mechanism involving phosphorylation of the largest subunit of RNA polymerase II.