No abstract

Real-time chemical imaging of bacterial activities can facilitate a comprehensive understanding of the dynamics of biofilm structures and functions. Synchrotron-radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy can yield high spatial resolution and label-free vibrational signatures of chemical bonds in biomolecules, but the abundance of water in biofilms has hindered SR-FTIR's sensitivity in investigating bacterial activity. We developed a simple open-channel microfluidic system that can circumvent the water-absorption barrier for chemical imaging of the developmental dynamics of bacterial biofilms with a spatial resolution of several micrometers. This system maintains a 10 microm thick laminar-flow-through biofilm system that minimizes both the imaging volume in liquid and the signal interference from geometry-induced fringing. Here we demonstrate the ability of the open-channel microfluidic platform to maintain the functionality of living cells while enabling high-quality SR-FTIR measurements. We include several applications that show how microbes in biofilms adapt to their immediate environments. The ability to directly monitor and map bacterial changes in biofilms can yield significant insight into a wide range of microbial systems, especially when coupled to more sophisticated microfluidic platforms.

Like most cities in developing countries, Uganda's capital city, Kampala, is experiencing urbanisation leading to an increase in population, and rapid development of peri-urban (informal) settlements. More than 60% of the city's population resides in these settlements which have the lowest basic service levels (sanitation, water supply, solid waste collection, stormwater and greywater disposal). A review of earlier studies on infrastructure development and sustainability within Kampala's peri-urban settlements, field surveys in a typical peri-urban settlement in the city (Bwaise III Parish), and structured interviews with key personnel from the National Water and Sewerage Corporation (NWSC), Kampala City Council (KCC), and the National Environment Management Authority (NEMA) were undertaken. Findings on current environmental health practices as well as perspectives of local communities and interviewed institutions on problems, constraints and possible solutions to basic service provision are presented. The implications of these viewpoints for possible environmental health interventions are presented.

Determining the transient chemical properties of the intracellular environment can elucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms that enable some obligate anaerobic bacteria to survive a sudden exposure to oxygen. Here we used high-resolution Fourier transform infrared (FTIR) spectromicroscopy to continuously follow cellular chemistry within living obligate anaerobes by monitoring hydrogen bond structures in their cellular water. We observed a sequence of well orchestrated molecular events that correspond to changes in cellular processes in those cells that survive, but only accumulation of radicals in those that do not. We thereby can interpret the adaptive response in terms of transient intracellular chemistry and link it to oxygen stress and survival. This ability to monitor chemical changes at the molecular level can yield important insights into a wide range of adaptive responses.Desulfovibrio ͉ hydrogen bond ͉ synchrotron FTIR spectromicroscopy ͉ oxygen stress ͉ cellular water

Using a fluorescein di-β-D-galactopyranoside (FDG) substrate we show that in live cells of an estrogen-sensitive yeast strain RMY/ER-ERE with human estrogen receptor (ERα) gene and the lacZ gene which encodes β-galactosidase, the uptake of 17 β-estradiol (E2) and the subsequent production of β-galactosidase enzyme occur quite rapidly, with maximal enzyme-catalyzed product formation evident after about 30 minutes of exposure to E2. This finding which agrees with the well-known rates of enzyme-catalyzed reactions could have implications for shortening the duration of environmental sample screening and monitoring regimes using yeast-based estrogen assays, and the development of biosensors for environmental estrogens to complement quantification methods.

In urban areas of Uganda, management of waste which consists of at least 70% organic content is accomplished by collection and disposal in landfills, resulting in emission of landfill gases among other impacts. Meanwhile, the limited number of wastewater and sludge treatment plants makes further management of sewage and faecal sludge generated from urban areas a major challenge. Thus, integrated sanitation systems which consider combined management of organic waste streams, i.e., bio waste, animal waste, sewage and faecal sludge, are proposed. The sanitation systems consist of a combination of anaerobic digestion and other technologies such as composting, incineration among others. Moreover, the systems also promote resource recovery in the form of biogas and organic fertilizer. The environmental feasibility of the integrated sanitation systems was investigated using life cycle assessment method. The results indicated that resource recovery contributed to the environmental feasibility of these sanitation systems. The more resources that were recovered from the sanitation systems, the lower the environmental impact.

Little is known about how children in humanitarian contexts experience self-wetting. Children can wet themselves due to having the medical condition of urinary incontinence (the involuntary leakage of urine), or due to them not wanting to or not being able to use the toilet facilities available (social or functional incontinence). Self-wetting is a global public health challenge: the physical health of children can suffer; they can miss out on educational and social opportunities; they may face increased protection risks; and the emotional effect on daily life can be significantly negative. The Story Book methodology was developed to facilitate conversations with children aged five to eleven in humanitarian contexts (specifically refugee settlements in Adjumani District, Uganda; and refugee camps in Cox’s Bazar, Bangladesh) about self-wetting to understand how humanitarian professionals can best meet the needs of children that wet themselves. This paper has evaluated how far the Story Book methodology meets the specific requirements of conducting research a) in a humanitarian context; b) with young children; and c) on a personal and highly sensitive topic. Data has been used from Story Book sessions held with children in Adjumani District and Cox’s Bazar, and from semi-structured interviews held with adults known to have participated in the planning and/or facilitation of the sessions. The evaluation found that although the Story Book methodology provided deep insights into how children in humanitarian contexts experience self-wetting, it was not always implemented as designed; it is not practical to implement in humanitarian settings; and it was not acceptable to all participants and facilitators as a research tool. Changes have been recommended to improve the methodology as a research tool to better understand how children experience personal health issues, but even with such changes the methodology will remain better suited to non-humanitarian contexts.

A yeast-based assay protocol developed for detecting oestrogenic activity in activated sludge (AS) supernatant is described. The protocol used Saccharomyces cerevisiae construct RMY/ER-ERE with human oestrogen receptor (ERα) and lacZ reporter genes, and was developed by modifying existing assays for use with AS samples from batch experiments. The method was able to detect total oestrogenic activity (without prior extraction) in supernatants of AS spiked with 17β-oestradiol (E2) with a detection limit of 0.03 ngE2-equivalent/ℓ and an overall quantification limit of 100 ngE2-equivalent/ℓ. Mean E2-induced oestrogenic activity recoveries of >56% were obtained from the spiked samples.