Continuous detection of viable micro-organisms by chemiluminescence

System monitors quality of reclaimed water continuously and automatically. Incubated samples are compared with unincubated ones by measuring their respective chemiluminescence

Wall Drag on Free-Moving Ciliated Micro-Organisms

It is generally assumed that wall drag on free-moving, self-propelled or passively moving micro-organisms is not significant under normal observation conditions. Yet the point at which such drag becomes significant has not been determined quantitatively. By comparing the relative velocities of sinking as well as swimming ciliates in tubes of various bore widths it has been determined that wall drag on sinking cells is about 8% significant at 108-132 body radii (or minor semi-axes) from the cell surface while the corresponding range for swimming cells is less than 1-4·2 body radii. These results are compared with the mathematical approximations for Stokes radius R_8 and depth of penetration of diffusing vorticity δ which characterize steady and quasi-steady Stokes flow respectively around a solid body. It is found that the asymptotic nature of the velocity profile of steady flow is reflected in the lack of agreement between R_8 and the measured distance for 8% drag. Conversely, the sharp gradient (or propulsive envelope) of the quasi-steady velocity profile is reflected in the substantial agreement between δ and the measured distance for > 0% drag. It is suggested that the given formula for δ which includes allowance for a propagated wave is a valid measure of the thickness of the quasi-steady region and that observations on motile ciliates be restricted to organisms at least 4 cell radii from the nearest wall if measurements free of wall-drag effects are to be obtained

Microbial degradation of dimethylsulphide and related C1-sulphur compounds: organisms and pathways controlling fluxes of sulphur in the biosphere

Dimethylsulphide (DMS) plays a major role in the global sulphur cycle. It has important implications for atmospheric chemistry, climate regulation, and sulphur transport from the marine to the atmospheric and terrestrial environments. In addition, DMS acts as an info-chemical for a wide range of organisms ranging from micro-organisms to mammals. Micro-organisms that cycle DMS are widely distributed in a range of environments, for instance, oxic and anoxic marine, freshwater and terrestrial habitats. Despite the importance of DMS that has been unearthed by many studies since the early 1970s, the understanding of the biochemistry, genetics, and ecology of DMS-degrading micro-organisms is still limited. This review examines current knowledge on the microbial cycling of DMS and points out areas for future research that should shed more light on the role of organisms degrading DMS and related compounds in the biosphere

A porous prolate-spheroidal model for ciliated micro-organisms

A fluid-mechanical model is developed for representing the mechanism of propulsion of a finite ciliated micro-organism having a prolate-spheroidal shape. The basic concept is the representation of the micro-organism by a prolate-spheroidal control surface upon which certain boundary conditions on the tangential and normal fluid velocities are prescribed. Expressions are obtained for the velocity of propulsion, the rate of energy dissipation in the fluid exterior to the cilia layer, and the stream function of the motion. The effect of the shape of the organism upon its locomotion is explored. Experimental streak photographs of the flow around both freely swimming and inert sedimenting Paramecia are presented and good agreement with the theoretical prediction of the streamlines is found

Chemical pretreatment for the distillation of urine

Pretreatment of urine prevents micro-organism growth in boiler and kills micro-organisms in condenser. Chemicals also clean evaporation surface, fix ammonia in boiling chamber, and suppress foaming

The impact of Paradise shelducks (Tadorna variegata) on pastoral communities and their role as reservoirs af agricultural diseases : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Ecology, Massey University, Auckland

Since its habitat expansion, due to human land clearance for farmland, paradise shelducks (Tadorna variegata) have established a firm foothold in the New Zealand agricultural environment. Paradise shelducks feed primarily on agricultural pasture and consequently compete directly with livestock for resources. As a result many farmers consider paradise shelducks to be a pest. In addition, it is a common perception that paradise shelducks contaminate agricultural land with their faeces. Although there is a wealth of information on the impacts of waterfowl on agricultural industries and diseases associated with waterfowl, no studies have specifically looked at the potential impact paradise shelducks pose on New Zealand's agricultural practices. The aims of this study were to 1) determine the presence and prevalence of pathogenic micro-organisms in paradise shelduck faeces and their associated environment, 2) evaluate the findings in terms of transmission routes and the relative risk to livestock and humans, 3) determine whether paradise shelducks have an affect on primary pasture production and composition, and 4) estimate the daily food intake rates of paradise shelducks. This study was based on a population of paradise shelducks in Tawharanui Regional Park over each of four seasons from 2006-2007. The prevalence of pathogenic micro-organisms was determined by paradise shelduck faecal surveys for selected bacteria and parasites. Surveys were conducted for flock birds and breeding pairs Additionally, faecal samples of sympatric species and water troughs were analysed. The impacts of paradise shelducks on pastoral communities was assessed by means of an exclusion experiment, consisting of two types of exclosure; a 'closed' exclosure to exclude all animals including paradise shelducks, and an 'open' exclosure to exclude livestock, but to allow access for paradise shelducks. Daily food intake rates for paradise shelducks were estimated from observational foraging data and necropsies ot paradise shelducks. Results show that no isolates of Salmonella. Campylobacter Yersinia. Cyrptospordium or Giardia were found. Relatively low prevalences of non haemolytic and alpha haemolytic Streptococci. Enterococcus, Bacillus, Clostridium perfringens, Proteus mirablis, strongyle eggs and Coccidia eggs were found. Additionally. E. coli was consistently isolated from the faecal samples throughout the sampling period. However, the serotypes of the micro-organisms isolated were not determined, so no conclusions could be drawn in relation to their pathogenicity. Furthermore, no significant correlations were found between the number of accumulated faeces sampled and the presence or prevalences of the micro-organisms isolated. It also appears that sampling during the driest times of the year will yield the highest presence of micro-organisms in paradise shelduck faeces. An array of micro-organisms, similar to those found in paradise shelduck faeces, were found in pukekos and house sparrow faeces as well as high contamination levels of faecal indicators in troughs. No conclusive transmission routes for the micro-organisms were found. Paradise shelducks were found to have a significant impact on pasture production and to selectively graze white clover (Trifolium repens). Furthermore, it was estimated that the paradise shelducks had a foraging intake rate of 104±15g/day of pasture dry matter. The results confirmed that paradise shelducks can have an affect on agricultural land. A more long term study in different regions is required to evaluate the full extent to which paradise shelducks affect agricultural production in New Zealand