Distribution and occurrence of bacterial fish diseases in the different cultural facilities of Lake Kainji area

Fish farming practices in the Lake Kainji Area of Nigeria are categorized under seven main cultural facilities, namely, earthen ponds/reservoirs, indoor/outdoor concrete tanks, plastic tanks, floating cages/hapas, aquaria, sewage and feral conditions. The presence of Bacteria isolates associated with diseased fish conditions varied significantly (P<0.05) with different cultural facilities. The highest bacteria isolates and bacterial disease incidence, 33% and 46% respectively, was associated with diseased fish in the indoor/outdoor concrete tanks. The least incidence of bacteria isolates (3.5%) and blue bacterial disease (3%) was associated with diseased fish in the aquaria and feral conditions. Nine Gram-negative and two Gram-positive bacteria genera were isolated during this investigation. Pseudomonas spp. (23.6%) and Staphylococcus spp. (14.3%), were the predominant Gram-negative and Gram-positive bacteria genera in the different cultural facilities, respectively. This paper highlights the relevance of occurrence and distribution of bacteria isolates associated with diseased fish to bacterial fish diseases under different cultural facilities

Watershed monitoring and the TMDL modeling to assess bacterial loading in estuarine environments to improve management

Shellfish bed closures along the North Carolina coast have increased over the years seemingly concurrent with increases in population (Mallin 2000). More and faster flowing storm water has come to mean more bacteria, and fecal indicator bacterial (FIB) standards for shellfish harvesting are often exceeded when no source of contamination is readily apparent (Kator and Rhodes, 1994). Could management reduce bacterial loads if the source of the bacteria where known? Several potentially useful methods for differentiating human versus animal pollution sources have emerged including Ribotyping and Multiple Antibiotic Resistance (MAR) (US EPA, 2005). Total Maximum Daily Load (TMDL) studies on bacterial sources have been conducted for streams in NC mountain and Piedmont areas (U.S. EPA, 1991 and 2005) and are likely to be mandated for coastal waters. TMDL analysis estimates allowable pollutant loads and allocates them to known sources so management actions may be taken to restore water to its intended uses (U.S. EPA, 1991 and 2005). This project sought first to quantify and compare fecal contamination levels for three different types of land use on the coast, and second, to apply MAR and ribotyping techniques and assess their effectiveness for indentifying bacterial sources. Third, results from these studies would be applied to one watershed to develop a case study coastal TMDL. All three watershed study areas are within Carteret County, North Carolina. Jumping Run Creek and Pettiford Creek are within the White Oak River Basin management unit whereas the South River falls within the Neuse River Basin. Jumping Run Creek watershed encompasses approximately 320 ha. Its watershed was a dense, coastal pocosin on sandy, relic dune ridges, but current land uses are primarily medium density residential. Pettiford Creek is in the Croatan National Forest, is 1133 ha. and is basically undeveloped. The third study area is on Open Grounds Farm in the South River watershed. Half of the 630 ha. watershed is under cultivation with most under active water control (flashboard risers). The remaining portion is forested silviculture.(PDF contains 4 pages)

Gut microbiota promote hematopoiesis to control bacterial infection

The commensal microbiota impacts specific immune cell populations and their functions at peripheral sites, such as gut mucosal tissues. However, it remains unknown whether gut microbiota control immunity through regulation of hematopoiesis at primary immune sites. We reveal that germ-free mice display reduced proportions and differentiation potential of specific myeloid cell progenitors of both yolk sac and bone marrow origin. Homeostatic innate immune defects may lead to impaired early responses to pathogens. Indeed, following systemic infection with Listeria monocytogenes, germ-free and oral antibiotic-treated mice display increased pathogen burden and acute death. Recolonization of germ-free mice with a complex microbiota restores defects in myelopoiesis and resistance to Listeria. These findings reveal that gut bacteria direct innate immune cell development via promoting hematopoiesis, contributing to our appreciation of the deep evolutionary connection between mammals and their microbiota.

On methods of evaluation of bacterial production. [Translation from: Lietuvas TSR Mokslu Akademijos Darbai, C Serija 2(55) 3-9, 1971.]

By now a great deal of work is known concerning the methods of determining the production of bacteria or similar questions; among these the problems of a common terminology is discussed. The article discusses formulae of production of bacterial populations over time.

Experimental culture of algal balls (Cladophora sauteri). Retention of original shape [Translation from: Bull.Jap.Soc.Phycol. Vol. 10, (1), p. 23-27, 1962]

It was on July 1960 when 10 algal balls were acquired for exhibition at Suma Aquarium, Kobe. Permission to remove the specimens from the Lake Akan Reserve was given by the National Nature Reserve Committee. Algal balls, as a rule, lose their natural beauty when they are kept in an ordinary tank for a certain length of time. In an effort to retain the natural beauty it was decided to exhibit them in culture. This paper summarises the findings of this experiments with Cladophora sauteri. The author concludes that serious consideration has to be given as to the intensity of light, the sunlight, the water temperature and the nutrition for algal balls in culture in order to retain the natural beauty and shape.

Bacterial production of nitrate in aquatic systems: progress report. Nitrate-loss processes in raw water

This short interim progress report builds on previous progress reports which have described the quantification of the process both within and between lakes of different degrees of eutrophication. These data indicated that slight changes in methodology, particularly when investigating sediment deposits, could grossly affect the measured activity. The aim of the present research was an attempt to rationalize these differences. If this could be achieved it would enable meaningful interpretation of published data obtained using different methods and therefore enlarge the available database. In addition some observations have been made on the production of nitrite by Grasmere profundal sediment slurries sampled during the circulation period.

Variation in bacterial populations in time and space

Obtaining a reliable estimate of the bacterial population is one of the main problems facing the bacterial ecologist. The author discusses the various methods available and concludes that the observed variability in bacterial populations depends on the sampling interval used.

Decomposition in lake sediments: bacterial action and interaction

This review discusses the processes involved in the decomposition of organic carbon derived initially from structural components of algae and other primary producers. It describes how groups of bacteria interact in time and space in a eutrophic lake. The relative importance of anaerobic and aerobic processes are discussed. The bulk of decomposition occurs within the sediment. The role of bacteria in the nitrogen cycle and the iron cycle, and in sulphate reduction and methanogenesis as the terminal metabolism of organic carbon are described.

A preliminary investigation of Elastomer Visible Implant (EVI)tag retention rates and the effect of tagging on the growth and survival of barbel (Barbus barbus L.).

The Elastomer Visible Implant system (EVI) is a relatively new technique for batch marking fish. The aim of this study was to assess retention rates and the possible effects of tagging on the growth and mortality of barbel, Barbus barbus, (81-197mm, fork length) over approximately 2 months using a syringe injection system.

Adenylate Cyclase Toxin promotes bacterial internalisation into non phagocytic cells

Bordetella pertussis causes whooping cough, a respiratory infectious disease that is the fifth largest cause of vaccine-preventable death in infants. Though historically considered an extracellular pathogen, this bacterium has been detected both in vitro and in vivo inside phagocytic and non-phagocytic cells. However the precise mechanism used by B. pertussis for cell entry, or the putative bacterial factors involved, are not fully elucidated. Here we find that adenylate cyclase toxin (ACT), one of the important toxins of B. pertussis, is sufficient to promote bacterial internalisation into non-phagocytic cells. After characterization of the entry route we show that uptake of "toxin-coated bacteria" proceeds via a clathrin-independent, caveolae-dependent entry pathway, allowing the internalised bacteria to survive within the cells. Intracellular bacteria were found inside non-acidic endosomes with high sphingomyelin and cholesterol content, or "free" in the cytosol of the invaded cells, suggesting that the ACT-induced bacterial uptake may not proceed through formation of late endolysosomes. Activation of Tyr kinases and toxin-induced Ca2+-influx are essential for the entry process. We hypothesize that B. pertussis might use ACT to activate the endocytic machinery of non-phagocytic cells and gain entry into these cells, in this way evading the host immune system.

Effect of towing speed on retention of zooplankton in bongo nets

Long-term time series of zooplankton data provide invaluable information about the fluctuations of species abundance and the stability of marine community structure. These data have demonstrated that environmental variability have a profound effect on zooplankton communities across the Atlantic basin (Beaugrand et al., 2002; Frank et al., 2005; Pershing et al., 2005). The value of these time series increases as they lengthen, but so does the likelihood of changes in sampling or processing methods. Sam-pling zooplankton with nylon nets is highly selective and biased because of mesh selectivity, net avoidance, and damage to fragile organisms. One sampling parameter that must be standardized and closely monitored is the speed of the net through the water column. Tow speed should be as fast as possible to minimize net avoid-ance by the organisms, but not so fast as to damage soft bodied zooplankters or extrude them through the mesh (Tranter et al., 1968; Anderson and Warren, 1991).

Surveying bacterial human pathogens in shrimp culture in Thailand

Any presence of bacterial human pathogen in shrimp products may be of public health concern. This note concludes that Salmonella do not appear to constitute a part of the microbial flora where shrimp culture is practiced in Thailand. Vibrio cholerae 01, the cause of cholera are rarely recovered from the environment with no isolates containing genes encoding cholera toxin. Further studies are needed to describe the prevalence of bacterial human pathogens in shrimp culture, especially determination of possible postharvest cross-contamnation with these pathogens

Avaliação microbiológica, detecção e susceptibilidade a antimicrobianos de potenciais enteropatógenos das famílias Enterobacteriaceae e Vibrionaceae em mexilhões Perna perna da praia de Itaipu, Niterói-RJ

Por serem organismos filtradores, os mexilhões devem ser extraídos para consumo somente de águas com padrões microbiológicos regulamentados pelo Conselho Nacional do Meio Ambiente, uma vez que intoxicações alimentares de origem bacteriana são as consequências mais comuns relacionadas ao consumo destes moluscos. Após a retirada dos costões, estes organismos passam por processos de fervura, lavagem, acondicionamento em sacos plásticos e transporte até a chegada ao mercado onde são comercializados; etapas estas, realizadas sem cuidados assépticos. Objetivando avaliar a qualidade microbiológica de mexilhões Perna perna coletados na praia de Itaipu, Niterói, RJ; após a sua fervura; e comercializados no Mercado São Pedro, foram realizadas contagens de coliformes totais e termotolerantes e pesquisa de Escherichia coli, Salmonella spp. e Vibrio spp. por metodologia convencional e molecular em amostras obtidas destes locais. Pelo teste de disco-difusão foi observado o perfil de resistência das cepas isoladas. Do total de amostras analisadas (27) apenas 3 dos mexilhões que sofreram processo de aferventação, 1 do comercializado e 3 do in natura, se encontravam dentro dos padrões aceitáveis pela legislação. Não houve diferença significativa entre as contagens de coliformes termotolerantes dos diferentes mexilhões analisados, mas sim entre os períodos seco e chuvoso. Somente uma das nove coletas de água mostrou-se própria para o cultivo de mexilhões (até 14 CF/mL). Foram isoladas e caracterizadas fisiológicamente, 77 estirpes da espécie E. coli, sendo confirmadas molecularmente por PCR os sorotipos EPEC, STEC e EAEC; 4 cepas Salmonella spp. sendo apenas uma confirmada por PCR; e das 57 cepas caracterizadas como Vibrio spp., 51 foram confirmadas por PCR, sendo 46 Vibrio spp., 2 V. cholerae, 1 V. vulnificus, 1 V. parahaemolyticus e 1 V. mimicus. Entre as estirpes de E. coli, 13% apresentaram multirresistência e 15,6% apresentaram resistência múltipla. A estirpe de Salmonella spp. se mostrou sensível a todos os antimicrobiados testados. Das estirpes de Vibrio spp. testadas, 68,6% apresentaram multirresistência e 72,5% apresentaram resistência múltipla. A partir da pesquisa de genes direto do caldo de enriquecimento foi possível detectar todos os genes pesquisados, com exceção para os sorotipos de Salmonella e V. cholerae. Baseado nos resultados do presente trabalho pode-se inferir que os mexilhões, amplamente comercializados no município de Itaipú, podem se constituir em risco para a saúde pública dos consumidores no Rio de Janeiro, necessitando dos órgãos competentes uma eficiente fiscalização nos pontos de venda e cultivo destes moluscos.

Blue Crab, Callinectes sapidus, Retention Rates in Different Trap Meshes

Percent escapements of blue crabs, Callinectes sapidus, by size and sex were determined for commercially available 38.1 mm square and hexagonal meshes and for five experimental squares. Commercial trap mesh sizes retained excessive numbers of sublegal blue crabs. Based on the criteria of maximizing sublegal crab escapement without an unacceptable loss of legal blue crabs, the 44.4 mm square (as measured from the inside of adjacent corners) was optimum and superior to either trap mesh used by fishermen.