Biomass relationship to growth and phosphate uptake ofPseudomonas fluorescens,Escherichia coli andAcinetobacter radioresistens in mixed liquor medium

The ability ofPseudomonas fluorescens, Escherichia coli andAcinetobacter radioresistenns to remove phosphate during growth was related to the initial biomass as well as to growth stages and bacterial species. Phosphate was removed by these bacteria under favourable conditions as well as under unfavourable conditions of growth. Experiments showed a relationship between a high initial cell density and phosphate uptake. More phosphate was released than removed when low initial cell densities (10²–10⁵ cells ml^–1) were used. At a high initial biomass concentration (10⁸ cells ml^–1), phosphate was removed during the lag phase and during logarthmic growth byP. fluorescens. Escherichia coli. at high initial biomass concentrations (10⁷ cells ml^–1), accumulated most of the phosphate during the first hour of the lag phase and/or during logarithmic growth and in some cases removed a small quantily of phosphate during the stationary growth phase.Acinetobacter radioresistens, at high initial cell densities (10⁶, 10⁷ cells ml^–1) removed most of phosphate during the first hour of the lag phase and some phosphate during the stationary growth phase.Pseudomonas fluorescens removed phosphate more thanA. radioresistens andE. coli with specific average ranges from 3.00–28.50 mg L^–1 compared to average ranges of 4.92–17.14 mg L^–1 forA. radioresistens and to average ranges of 0.50–8.50 mg L^–1 forE. coli.     

Cryptosporidium species and subtypes in river water and riverbed sediment using next-generation sequencing

This study uncovered the prevalence, harboured species, and subtype diversity of Cryptosporidium species in river water and its sediment from the Apies River in South Africa. Cryptosporidium spp. concentrations in freshwater and its sediment were determined using Ziehl-Neelsen staining and quantitative Polymerase Chain Reaction (qPCR) techniques. Next-generation sequencing (NGS) targeting the 60 kDa glycoprotein (gp60) gene of Cryptosporidium spp. was performed to reveal the species, subtype families and subtypes harboured in freshwater and its sediment. Although the results revealed that water samples had a higher prevalence (30%) compared with sediment (28%), the number of observable Cryptosporidium spp. oocysts in sediment samples (ranging from 4.90 to 5.81 log₁₀ oocysts per 1 Liter) was higher than that of river water samples (ranging from 4.60 to 5.58 log₁₀ oocysts per 1 L) using Ziehl-Neelsen staining. The 18S ribosomal ribonucleic acid (rRNA) gene copy of Cryptosporidium in riverbed sediments ranged from 6.03 to 7.65 log₁₀, whereas in river water, it was found to be between 4.20 and 6.79 log₁₀. Subtyping results showed that in riverbed sediments, Cryptosporidium parvum accounted for 40.72% of sequences, followed by Cryptosporidium hominis with 23.64%, Cryptosporidium cuniculus with 7.10%, Cryptosporidium meleagridis with 4.44% and the least was Cryptosporidium wrairi with 2.59%. A considerable percentage of reads in riverbed sediment (21.25%) was not assigned to any subtype. River water samples had 45.63% of sequences assigned to C. parvum, followed by 30.32% to C. hominis, 17.99% to C. meleagridis and 5.88% to C. cuniculus. The data obtained are concerning, as Cryptosporidium spp. have intrinsic resistance to water treatment processes and low infectious doses, which can pose a risk to human health due to the various uses of water (for human consumption, leisure, and reuse).     

The curious case of Hermodice carunculata (Annelida: Amphinomidae): evidence for genetic homogeneity throughout the Atlantic Ocean and adjacent basins

Over the last few decades, advances in molecular techniques have led to the detection of strong geographic population structure and cryptic speciation in many benthic marine taxa, even those with long‐lived pelagic larval stages. Polychaete annelids, in particular, generally show a high degree of population divergence, especially in mitochondrial genes. Rarely have molecular studies confirmed the presence of ‘cosmopolitan’ species. The amphinomid polychaete Hermodice carunculata was long considered the sole species within its genus, with a reported distribution throughout the Atlantic and adjacent basins. However, recent studies have indicated morphological differences, primarily in the number of branchial filaments, between the East and West Atlantic populations; these differences were invoked to re‐instate Hermodice nigrolineata, formerly considered a junior synonym of H. carunculata. We utilized sequence data from two mitochondrial (cytochrome c oxidase subunit I, 16S rDNA) markers and one nuclear (internal transcribed spacer) marker to examine the genetic diversity of Hermodice throughout its distribution range in the Atlantic Ocean, including the Mediterranean Sea, the Caribbean Sea, the Gulf of Mexico and the Gulf of Guinea. Our analyses revealed generally low genetic divergences among collecting localities and between the East and West Atlantic, although phylogenetic trees based on mitochondrial data indicate the presence of a private lineage in the Mediterranean Sea. A re‐evaluation of the number of branchial filaments confirmed differences between East and West Atlantic populations; however, the differences were not diagnostic and did not reflect the observed genetic population structure. Rather, we suspect that the number of branchial filaments is a function of oxygen saturation in the environment. Our results do not support the distinction between H. carunculata in the West Atlantic and H. nigrolineata in the East Atlantic. Instead, they re‐affirm the older notion that H. carunculata is a cohesive species with a broad distribution across the Atlantic Ocean.     

Combining chlorination and chloramination processes for the inhibition of biofilm formation in drinking surface water system models

AIMS: The aim of this study was to investigate the inhibition of biofilm formation on stainless steel (SS) and galvanized mild steel (MS) in chlorine (AFC(1)) and chlorine-monochloramine treated waters (AFC(2)M). METHODS AND RESULTS: Disinfection was carried out using 2.5 mg l(-1) free chlorine followed by 1.5 mg l(-1) monochloramine, with non-disinfected water used as control water. Results of the standard spread plate procedure, DAPI epifluorescence microscopy and scanning electron microscopy revealed bacterial colonization of SS and MS exposed to non-disinfected and chlorinated waters between 24 and 720 h, while no bacterial adhesion was detected on SS and MS exposed to AFC(2)M between 48 and 504 h. CONCLUSIONS: The inability of bacteria to grow on SS and MS was observed only when 0.35 mg l(-1) residual monochloramine was maintained throughout the system. SIGNIFICANCE AND IMPACT OF THE STUDY: This demonstrates the inability of chlorine alone to inhibit bacterial growth and suggests a combination of chlorine and monochloramine as a more effective treatment for drinking water, especially for rural communities with very poor source waters in Africa.     

Application of the Three Rs to challenge assays used in vaccine testing: Tenth report of the BVAAWF/FRAME/RSPCA/UFAW Joint Working Group on Refinement

This report aims to facilitate the implementation of the Three Rs (reduction, refinement and replacement) in the testing of vaccines for regulatory and other purposes. The focus is predominantly on identification of reduction and refinement opportunities in batch potency testing but the principles described are widely applicable to other situations that involve experimental infections of animals. The report should also help to interpret the requirements of the European Pharmacopoeia with regard to the use of alternative tests, humane endpoints and other refinements. Two specific worked examples, for batch potency testing of Clostridium chauvoei and canine leptospira, with recommendations for harmonisation of international test requirements for these and other vaccines, are provided as appendices online.     

Evaluation and selection of tandem repeat loci for a Brucella MLVA typing assay

Background  

The classification of Brucella into species and biovars relies on phenotypic characteristics and sometimes raises difficulties in the interpretation of the results due to an absence of standardization of the typing reagents. In addition, the resolution of this biotyping is moderate and requires the manipulation of the living agent. More efficient DNA-based methods are needed, and this work explores the suitability of multiple locus variable number tandem repeats analysis (MLVA) for both typing and species identification.     

Home Office licence abstracts--an assessment

Since late in 2004, brief abstracts of projects licensed under the Animals (Scientific Procedures) Act 1986 have been published on the Home Office website. These are produced by the Project Licence Holders, and their publication is seen by the Home Office as contributing to greater openness and to greater public understanding of the use of animals in science, and how it is regulated. Here, we assess the value of the database for this purpose, based on an examination of the 1400 abstracts published up to January 2008. The abstracts are generally strong on justification, but often very poor at describing the likely effects on the animals used. In many cases, they lack basic information on the procedures applied, and the numbers, and even the species, of animals involved. A significant number of projects lack abstracts altogether. In order to ensure that the database gives a complete and balanced picture of animal use in research, we consider that it should be mandatory to submit an abstract, which should include at least the species and numbers of animals used, the adverse effects they are likely to experience, and the severity limits assigned to the procedures applied to them. The value of the database would also be improved greatly, if it were more readily searchable, at least by species, level of severity, and broad area of research.     

Algal contact as a trigger for coral disease

Diseases are causing alarming declines in reef‐building coral species, the foundation blocks of coral reefs. The emergence of these diseases has occurred simultaneously with large increases in the abundance of benthic macroalgae. Here, we show that physical contact with the macroalga Halimeda opuntia can trigger a virulent disease known as white plague type II that has caused widespread mortality in most Caribbean coral species. Colonies of the dominant coral Montastraea faveolata exposed to algal transplants developed the disease whereas unexposed colonies did not. The bacterium Aurantimonas coralicida, causative agent of the disease, was present on H. opuntia sampled close to, and away from diseased corals, indicating that the alga serves as a reservoir for this pathogen. Our results suggest that the spread of macroalgae on coral reefs could account for the elevated incidence of coral diseases over past decades and that reduction of macroalgal abundance could help control coral epizootics.     

Molecular and immunological characterization of the major outer membrane proteins of Brucella

Abstract Saccharomyces cerevisiae exponentially growing in basic or 0.7 M NaCl medium were isotopically labelled with ³⁵S-methionine, followed by protein separation and quantification by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) combined with computerised image analysis. The electrophoretic separation resolved about 650 proteins of which 13 displayed significant and at least 2-fold changes in rate of synthesis during saline growth. By sequencing of 2D-PAGE resolved proteins, one of the 8 induced spot, p42.9/5.5, was shown to correspond to the full length (containing the N-terminal extension) product of the GPD 1 gene encoding the cytoplasmic glycerol 3-phosphate dehydrogenase. The expression of the TDH 3 gene, glyceraldehyde 3-phosphate dehydrogenase, and the ENO 2 gene, enolase, decreased during growth in NaCl medium, declines hypothesised to have an impact on the flux to glycerol.     

Nitrogen fixation and diversity of benthic cyanobacterial mats on coral reefs in Curaçao

Coral Reefs - Benthic cyanobacterial mats (BCMs) have increased in abundance on coral reefs worldwide. However, their species diversity and role in nitrogen fixation are poorly understood. We...