Additions to the mycobiota of the invasive weed Miconia calvescens (Melastomataceae)

Miconia calvescens (Melastomataceae) is a shrub or small tree native to the Neotropics that has become one of the worst invaders of forest ecosystems, particularly in Pacific islands such as Hawaii and French Polynesia. It has been a target for biological control for more than 10 y, both with arthropod and pathogen natural enemies. Until now Colletotrichum gloeosporioides f. sp. miconiae was the only organism to be used in biological control against this weed. This fungus was introduced both in Hawaii and in French Polynesia in the late 1990s/early 2000s, where it has caused some damage to the weed, but it became evident that additional agents are needed to achieve adequate control. Exploratory surveys for plant pathogens as potential biocontrol agents of M. calvescens were undertaken in Brazil, Costa Rica and Ecuador and yielded a diverse list of pathogens, including one phytoplasma, two nematodes, one oomycete and numerous fungi. A study including the description of five fungal species found attacking M. calvescens was published recently. Herein the following additional fungi also belonging to the mycobiota of M. calvescens are described: Hyalosphaera ornata sp. nov, Microsphaeropsis miconiae sp. nov., Myrothecium miconiae sp. nov., Phyllachora miconiiphila sp. nov., as well as Hyalosphaera miconiae, Lembosia melastomatum and Microsphaeropsis clidemiae, which are recorded here for the first time on this host. Although preliminary our observations of damage to M. calvescens caused by these seven fungal species did not indicate any potential for use in classical biological control.

Brazilian mycobiota of the aquatic weed Sagittaria montevidensis

Nine species of fungi on the aquatic weed Sagittaria montevidensis (arrowhead) in southern and southeastern Brazil were collected, identified, described and illustrated in a survey for possible biological control agents against this weed. Seven of them are anamorphic fungi, Alternaria alternata, Botrytis cinerea, Cercospora apii, Cercospora sagittariae, Colletotrichum gloeosporioides, Plectosporium alismatis and Pseudocercospora arthrospora, and two smut fungi, Doassansiopsis deformans and Narasimhania alismatis. All represent new host records or new geographic localities for occurrences of the fungi. Pseudocercospora arthrospora is new to science. It differs from known species of genus Pseudocercospora mainly by its subhyaline and disarticulating conidia and host. This fungus is close to Thedgonia but can be distinguished for this genus by its conidiogenesis. Based on the description and disease symptoms Cylindrocarpon sagittariae, recorded on S. trifolia from Japan, is regarded here as a later synonym of Plectosporium alismatis. Preliminary observations of the fungi in the field and in culture suggest that four of these have potential for use as biocontrol agents against S. montevidensis, namely C. sagittariae, C. gloeosporioides, P. alismatis and P. arthrospora.

Calidion bombacis, a new combination for Uredo bombacis with the record of Bombacopsis glabra (Bombacaceae) as a new host from Brazil

The new combination Calidion bombacis is proposed for the rust species formerly known as Uredo bombacis. This nomenclatural change is based on the examination of newly collected material of this fungus from a new host, Bombacopsis glabra from Brazil, and reexamination of the isotype. Until now this fungus was only known to occur in Asia (China, India and Sri Lanka). Therefore, this is also the first record of this fungus from the Neotropics.

Archaeal histones: structures, stability and DNA binding

Structures, stability and DNA-binding properties have been established for archaeal histones from mesophiles, thermophiles and hyperthermophiles. Most archaeal histones are simply histone folds that are stabilized by dimer formation. Archaeal histones and the histone folds of the eukaryotic nucleosome core histones share a common ancestry and bind and wrap DNA similarly using conserved residues. The histone-fold residues that stabilize dimer–dimer interactions within an archaeal histone core contribute to determining archaeal histone–DNA affinity.

Mutational analysis of archaeal histone-DNA interactions

Site-specific mutagenesis of the hmfB gene cloned from the archaeon Methanothermus fervidus, followed by expression in Escherichia coli, has been used to generate approximately 90 recombinant (r) variants of the archaeal histone HMfB. The abilities of these variants to form stable archaeal nucleosome-containing complexes with linear pBR322 DNA, and with an 89 bp restriction fragment of this DNA have been determined. Variants that failed to form such complexes, based on negative gel-shift assays, had substitutions at the N terminus or within the alpha1, L1 and L2 regions of the rHMfB histone fold, at sites predicted to be homologous to eucaryal histone fold residues that contact the DNA in the eucaryal nucleosome. Variants that failed to give gel shifts were further assayed for their abilities to facilitate ligase-catalyzed circularization of a linear 88 bp DNA molecule, and to reduce the ellipticity of a DNA solution at 275 nm (theta(275)). Consistent with cooperative but independent sites of DNA binding, a combination of three residue substitutions, one each in alpha1, L1 and L2, was required to generate a rHMfB variant with no detectable DNA binding based on gel shift, circularization and theta(275) reduction assays.

Relapse with multibacillary leprosy caused by rifampicin sensitive organisms following paucibacillary multidrug therapy

Many leprosy patients treated with multidrug therapy (MDT) had previously received dapsone (DDS) monotherapy for many years. We report here 2 such patients treated with modified paucibacillary MDT composed of rifampicin and DDS who subsequently relapsed with multibacillary leprosy 5 and 6 years after release from treatment. Isolates of Mycobacterium leprae from both patients were resistant to DDS but sensitive to rifampicin, suggesting that the relapses were caused by rifampicin sensitive 'persister' organisms. The implications of this for surveillance of patients released from treatment (RFT) and the management of relapsed patients is discussed.

Advantages, indications, and the manufacturing of melted PVC waterpipe splints

There are several indications when to use splints in the treatment of leprosy. PVC waterpipe is a cheap and easily available material in developing countries. Its advantages, indications, and the manufacturing of splints are described.

The role of IgM antiphenolic glycolipid-1 antibodies in assessing household contacts of leprosy patients in a low endemic area

This study was carried out to assess the role PGL-1 antibodies may have to play in assisting with early diagnosis in close contacts of leprosy patients. Blood samples were collected from patients and contacts. It was found that 6.9% of index cases and 1% of healthy contacts were positive for PGL-1 antibody. None of the healthy contacts developed clinical leprosy and all had become seronegative at follow-up. We conclude that screening for PGL-1 antibodies has a limited role in the screening of healthy contacts and may not be of use in low endemic areas.