Screening environmental samples for source-specific bacteriophage hosts using a method for the simultaneous pouring of 12 petri plates

A simple apparatus was developed to allow 12 petri plates to be poured simultaneously by hand. It was used when screening bacterial isolates from sewage and dog feces for their ability to detect phages from these sources. This was done to assess the ease with which source-specific phage hosts can be isolated from these sources of fecal pollution. Host bacteria that consistently detected phages from sewage were easily isolated from sewage. These bacterial isolates did not detect phages from dog feces. Host bacteria were not isolated from dog feces even after screening hundreds of colonies from fecal samples from six dogs. Journal of Industrial Microbiology & Biotechnology (2000) 24, 124–126. Received 06 July 1999/ Accepted in revised form 05 November 1999     

Analysis of genetic changes in radiated and non-radiated bulk oat (Avena sativa L.) populations

Summary In both radiated and non-radiated oat populations inbreeding coefficients increased more slowly than was expected on the assumption of full selfing and equal selective values for homozygotes and heterozygotes. Assuming 1% outcrossing for oats and a selective value of 1.0 for the mean, the heterozygotes for two loci governing crown rust reaction have an advantage of 50% over the homozygotes. This study supports previous observations that the heterozygote often has a decided advantage in predominantly self-pollinated crops.     

Statistical techniques for detection of major genes in animal breeding data

Summary Statistical techniques for detection of major loci and for making inferences about major locus parameters such as genotypic frequencies, effects and gene action from field-collected data are presented. In field data, major genotypic effects are likely to be masked by a large number of environmental differences in addition to additive and nonadditive polygenic effects. A graphical technique and a procedure for discriminating among genetic hypotheses based on a mixed model accounting for all these factors are proposed. The methods are illustrated by using simulated data.Journal Paper No. J-12733 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1901     

Growth and survival ofAzospirillum brasilense andArthrobacter giacomelloi in binary continuous culture

Summary Azospirillum brasilense andArthrobacter giacomelloi were grown in single and mixed succinate-limited continuous cultures at a partial oxygen pressure of 0.01atm. Growth, viability and survival during nutrient starvation were examined at various dilution rates. At D=0.05 h^–1, K_s values for succinate consumed were calculated.Arthrobacter giacomelloi viability was inversely related to dilution rate whereasAzo. brasilense was directly related. Slightly lower values of viability were obtained in mixed culture, but the ratio between the microorganisms was constant. The survival ofArth. giacomelloi in single culture decreased with increasing growth rate while survival ofAzo. brasilense was directly related to dilution rate. Acetylene reduction activity was generally very low in both single and mixed cultures. Respiration rate was also determined and the mixed culture showed an oxygen uptake rate higher than that of single cultures.Research work supported by CNR, Italy. Special grant I.P.R.A. Sub-project 1. Paper N. 317.     

Antigenic profiles of human,bovine and canine articular chondrocytes

Summary Human, bovine and canine articular chondrocytes have been shown to bear cartilage matrix, chondrocyte-specific and histocompatibility antigens. These cell-surface antigens of chondrocytes were demonstrated both simultaneously and separately either by complement-mediated cytotoxicity or by immunohistochemical reactions. The chondrocyte-specific antigens involve subsets of species-common and species-specific determinants, which are also present on the surfaces of rib and laryngeal chondrocytes. In addition to these antigens, human and calf articular chondrocytes also express unique cell-surface components that are capable of producing a blastogenic stimulation of autologous T-lymphocytes in vitro. These putative autoantigens segregated from lymphocytes in vivo could be released in trauma and in inflammatory joint diseases triggering the immune system of the host.     

Some characteristics of monolayers of 1-palmitoyl-2-oleoyl-phosphatidylglycerol with and without dipalmitoylphosphatidylcholine during dynamic compression and expansion

Some properties of monolayers of $\text{1-}\text{palmitoyl}\text{-2-}\text{oleoyl}\text{-sn-}\text{glycero}\text{-3-}\text{phospho}\text{-rac-}\text{glycerol}$ (POPG) alone or of POPG in mixtures with $\text{1,2-}\text{dipalmitoyl}\text{-sn-}\text{glycero}\text{-3-}\text{phosphocholine}$ (DPPC) have been measured near 35°C during dynamic compression and expansion at 3.6 cm²·s^?1. (2) The mean values of minimum surface tension (corresponding to maximum surface pressure) which could be obtained with pure POPG monolayers at high compression ranged from 15 to 18 mN·m^?1 in the presence of Na⁺, Ca²⁺ or low pH (2.0) in the subphase. (3) The presence of Ca²⁺ or low pH in the subphase increased the collapse plateau ratios obtained on cyclic compression. This might represent enhanced respreading into the monolayer of pure POPG from a collapsed form during reexpansion of the surface. (4) Monolayers containing 10% or 30% POPG and 90% or 70% DPPC could be compressed to surface tensions approaching zero. (5) In such mixed monolayers, 10% or 30% POPG did not appear to enhance respreading, as measured by collapse plateau ratios, in the presence of Na⁺ or Ca²⁺ in the subphase.     

A comparative study of ciliated protozoa communities in activated-sludge plants

Abstract: Ciliated protozoa present in ten activated sludge plants at Madrid (Spain) were identified. The abundance of key groups of ciliates was determined at each plant; attached ciliates made up the most abundant and representative group. Multivariate statistical analysis was employed to study relationships between ciliates and both the physico-chemical and operational parameters of the plants. Partial correlation analysis revealed: (1) The indicator value of attached ciliates in assessing management and performance of the activated sludge process, (2) the relationship of swimming ciliates with short-aged sludges and lower quality effluents and (3) the direct association between swimming-crawling ciliates and bad settlement conditions of the sludge. Factor analysis showed the associations of the most frequent species of ciliates with the operational parameters of the plants, suggesting the indicator value of some of the species: Vorticella striata was related with poor quality of effluent; Aspidisca cicada with stable plant conditions, and Litonotus lamella with a deficiently settling sludge.     

Keratinolytic fungi in sewage sludge

Sewage sludge from the Upper Silesia Region of Poland were surveyed for keratinolytic fungi. Out of 100 Petri dishes examined, 89 were positive for these micro-organisms. Altogether, 185 fungal appearances belonging to 10 species were observed. Trichophyton terrestre with its teleomorph Arthroderma quadrifidum, T. ajelloi with A. uncinatum, Microsporum gypseum with Arthroderma sp., and Chrysosporium keratinophilum with Aphanoascus keratinophilus prevailed in the sludges. The sewage treatment technologies together with the sludge structure, humidity and pH were found to be critical factors determining the occurrence of keratinolytic fungi in the sludge environment. The qualitative and quantitative composition of keratinolytic fungi could be a useful tool in evaluation of sludge treatment processes.