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A letter to the editor is presented describing the equipment used in measuring the incidence of medullation in wool.

Prolonged exposure to high temperatures can cause heat-related illnesses and accelerate death, especially in the elderly. We developed a locally-appropriate Healthy Environment Assessment Tool, or 'HEAT' tool, to assess heat-health risks among communities. HEAT was co-developed with stakeholders and practitioners/professionals from the Rustenburg Local Municipality (RLM), a setting in which heat was identified as a risk in an earlier study. Feedback was used to identify vulnerable groups and settings in RLM, consider opportunities and barriers for interventions, and conceptualize a heat-health vulnerability assessment tool for a heat-resilient town. Using information provided by the RLM Integrated Development Plan, the HEAT tool was applied in the form of eight indicators relating to heat-health vulnerability and resilience and areas were evaluated at the ward level. Indicators included population, poverty, education, access to medical facilities, sanitation and basic services, public transport, recreation/community centres, and green spaces. Out of 45 wards situated in the municipality, three were identified as critical risk (red), twenty-eight as medium-high risk (yellow), and six as low risk (green) in relation to heat-health vulnerability. Short-term actions to improve heat health resilience in the community were proposed and partnerships between local government and the community to build heat health resilience were identified.

The thoracic bristle pattern of Drosophila results from the spatially restricted expression of the achaete-scute (ac-sc) genes in clusters of cells, mediated by the activity of many discrete cis-regulatory sequences. However, ubiquitous expression of sc or asense (ase) achieved with a heterologous promoter, in the absence of endogenous ac-sc expression, and the activity of the cis-regulatory elements, allows the development of bristles positioned at wild-type locations. We demonstrate that the products of the genes stripe, hairy, and extramacrochaetae contribute to rescue by antagonizing the activity of Sc and Ase. The three genes are expressed in specific but overlapping spatial domains of expression that form a prepattern that allows precise positioning of bristles. The redundant mechanisms might contribute to the robustness of the pattern. We discuss the possibility that patterning in trans by antagonism is ancestral and that the positional cis-regulatory sequences might be of recent origin.

Two distinct roles are described for Dorsal, Dif and Relish, the three NF-kappaB/Rel proteins of Drosophila, in the development of the peripheral nervous system. First, these factors regulate transcription of scute during the singling out of sensory organ precursors from clusters of cells expressing the proneural genes achaete and scute. This effect is possibly mediated through binding sites for NF-kappaB/Rel proteins in a regulatory module of the scute gene required for maintenance of scute expression in precursors as well as repression in cells surrounding precursors. Second, genetic evidence suggests that the receptor Toll-8, Relish, Dif and Dorsal, and the caspase Dredd pathway are active over the entire imaginal disc epithelium, but Toll-8 expression is excluded from sensory organ precursors. Relish promotes rapid turnover of transcripts of the target genes scute and asense through an indirect, post-transcriptional mechanism. We propose that this buffering of gene expression levels serves to keep the neuro-epithelium constantly poised for neurogenesis.

Ninety-six isolates of Klebsiella pneumoniae and K. oxytoca were recovered from wild mammals in Australia. 14.6% of these bacteria produce killing phenotypes that suggest the production of bacteriocin toxins. Cloning and sequencing of the gene clusters encoding two of these killing phenotypes revealed two instances of a bacteriocin associated with a bacteriophage gene, the first such genetic organization described. The newly identified klebicin C gene cluster was discovered in both K. pneumoniae and K. oxytoca. The newly identified klebicin D gene cluster was detected in K. oxytoca. Protein sequence comparisons and phylogenetic inference suggest that klebicin C is most closely related to the rRNase group of colicins (such as colicin E4), while klebicin D is most closely related to the tRNase group of colicins (such as colicin D). The klebicin C and D gene clusters have similar genetic and regulatory organizations. In both cases, an operon structure is inferred consisting of a phage-associated open reading frame and klebicin activity and associated immunity genes. This novel bacteriophage/bacteriocin organization may provide a novel mechanism for the generation of bacteriocin diversity in Klebsiella.

Microbes produce an extraordinary array of microbial defense systems. These include broad-spectrum classical antibiotics critical to human health concerns; metabolic by-products, such as the lactic acids produced by lactobacilli; lytic agents, such as lysozymes found in many foods; and numerous types of protein exotoxins and bacteriocins. The abundance and diversity of this biological arsenal are clear. Lactic acid production is a defining trait of lactic acid bacteria. Bacteriocins are found in almost every bacterial species examined to date, and within a species, tens or even hundreds of different kinds of bacteriocins are produced. Halobacteria universally produce their own version of bacteriocins, the halocins. Streptomycetes commonly produce broad-spectrum antibiotics. It is clear that microbes invest considerable energy in the production and elaboration of antimicrobial mechanisms. What is less clear is how such diversity arose and what roles these biological weapons play in microbial communities. One family of microbial defense systems, the bacteriocins, has served as a model for exploring evolutionary and ecological questions. In this review, current knowledge of how the extraordinary range of bacteriocin diversity arose and is maintained in one species of bacteria, Escherichia coli, is assessed and the role these toxins play in mediating microbial dynamics is discussed.