Some features of coagulase positive staphylococci from bovine milk. II. Comparison of conventional techniques and the API Staph system

A total of 150 isolates of Staphylococcus aureus were subjected to the tests on the API Staph system. Of these, 50 were also tested by conventional methods, using the same tests as those found on the API Staph strips. Applying the principles of numerical taxonomy, the relationship between these isolates was 82% and more. Tests for the metabolism of sucrose and N-acetyl-glucosamine and for the production of argenine dihydrolysate and urease appear to be superfluous in the identification of S. aureus in this system.     

Effects of supplementing pregnant heifers with methionine or melatonin on the anatomy and other characteristics of their lateral hind claws

Three groups of four primiparous Holstein-Friesian heifers were fed throughout pregnancy either a control diet or that diet supplemented with either 5 to 6 g per day of rumen-protected intestinally available methionine or 25 mg melatonin. They were euthanased three days after calving. The dietary supplements had no effect on the impression hardness or the concentrations of cysteine and methionine in samples of claw horn collected from a range of sites, or on the areas of erosion in the sole and heel. Significant differences were recorded for the hardness of the horn in the order wall >sole >heel. These differences were associated with higher concentrations of cysteine and lower concentrations of methionine in samples of horn from the dorsal wall than in samples from the prebulbar region of the sole. There were no significant differences attributable to the dietary supplements in the soft tissue anatomy of the solear dermis and epidermis.     

Development and evaluation of a high-throughput,low-cost genotyping platform based on oligonucleotide microarrays in rice

Background  

We report the development of a microarray platform for rapid and cost-effective genetic mapping, and its evaluation using rice as a model. In contrast to methods employing whole-genome tiling microarrays for genotyping, our method is based on low-cost spotted microarray production, focusing only on known polymorphic features.     

Rapid flow cytometric analysis of the cell cycle in intact plant tissues

Mechanical chopping of plant tissues in the presence of mithramycin released intact nuclei representative of the cells within the tissues. The amount of nuclear DNA in the homogenates of monocotyledonous and dicotyledonous plants was accurately and rapidly determined by flow microfluorometry, and the distribution of nuclei involved in the cell cycle was charted for tissues selected from different physical locations or developmental stages.     

No DNA loss in autotetraploids of Arabidopsis thaliana

To address the issue of genome evolution in autopolyploids and particularly to investigate whether rapid sequence elimination also occurs in autopolyploids as in allopolyploids, amplified fragment length polymorphism (AFLP) fingerprinting was employed to examine a large number of genomic loci in F₁ hybrids between two different autotetraploids of Arabidopsis thaliana accessions, namely Ler and Col. Using this approach, perfect additivity in the F₁ hybrids was found between the newly‐formed autopolyploids when compared with their parental lines. Using flow cytometry, the study was extended in a quantitative manner, in which the nuclear DNA contents in one autotetraploid A. thaliana accession Ler, was determined. The increase in genome size of the autotetraploid line was additive. Taken together, no evidence was found for genome size reduction due to autopolyploidization of A. thaliana. The results indicating that there was no DNA loss in autotetraploid A. thaliana suggest that a different type of genome evolution may occur in autopolyploids during the initial stages of their formation when compared with allopolyploids.     

Identification of genomic regions that exhibit sexual dimorphism for size and muscularity in cattle

Sexual dimorphism, the phenomenon whereby males and females of the same species are distinctive in some aspect of appearance or size, has previously been documented in cattle for traits such as growth rate and carcass merit using a quantitative genetics approach. No previous study in cattle has attempted to document sexual dimorphism at a genome level; therefore, the objective of the present study was to determine whether genomic regions associated with size and muscularity in cattle exhibited signs of sexual dimorphism. Analyses were undertaken on 10 linear-type traits that describe the muscular and skeletal characteristics of both males and females of five beef cattle breeds: 1,444 Angus (AA), 6,433 Charolais (CH), 1,129 Hereford, 8,745 Limousin (LM), and 1,698 Simmental. Genome-wide association analyses were undertaken using imputed whole-genome sequence data for each sex separately by breed. For each single-nucleotide polymorphism (SNP) that was segregating in both sexes, the difference between the allele substitution effect sizes for each sex, in each breed separately, was calculated. Suggestively (P ≤ 1 × 10⁻⁵) sexually dimorphic SNPs that were segregating in both males and females were detected for all traits in all breeds, although the location of these SNPs differed by both trait and breed. Significantly (P ≤ 1 × 10⁻⁸) dimorphic SNPs were detected in just three traits in the AA, seven traits in the CH, and three traits in the LM. The vast majority of all segregating autosomal SNPs (86% in AA to 94% in LM) had the same minor allele in both males and females. Differences (P ≤ 0.05) in allele frequencies between the sexes were observed for between 36% (LM) and 66% (AA) of the total autosomal SNPs that were segregating in both sexes. Dimorphic SNPs were located within a number of genes related to muscularity and/or size including the NAB1, COL5A2, and IWS1 genes on BTA2 that are located close to, and thought to be co-inherited with, the MSTN gene. Overall, sexual dimorphism exists in cattle at the genome level, but it is not consistent by either trait or breed.     

Detecting the undetectable: Characterization,optimization, and validation of an eDNA detection assay for the federally endangered dwarf wedgemussel,Alasmidonta heterodon (Bivalvia: Unionoida)

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Human-altered and human-transported (HAHT) soils in the U.S. soil classification system

ABSTRACT

Human-altered and human-transported (HAHT) soils are widespread across the globe and are concentrated near where people live and work. Although some of the HAHT soils are significant because they can be hazardous to human, animal, and plant health, most are not mapped or classified to the same extent as agricultural soils. The purpose of this article is to discuss the occurrence, types, and importance of HAHT soils and to document the historical and proposed classification of HAHT soils in Soil Taxonomy. There are two main forms of materials that define HAHT soils: human-altered soils formed in human-altered materials (HAM) from the soil surface to 50 cm (or to bedrock if shallower) or more and human-transported soils formed in human-transported materials (HTM) from the soil surface to 50 cm (or to bedrock if shallower) or more. The HAHT soils mainly occur in urban areas, transportation corridors, mined lands, landfills, filled shallow water, and agricultural areas on anthropogenic landforms. Hazards include danger from radioactivity, pollution, content of hazardous artifacts, or presence on unstable landforms that may fail during heavy rains or earthquakes. The HAHT soils are extensive, and their extent is growing. In the past, few HAHT soils were described or classified adequately because the U.S. Soil Taxonomy system was established for agricultural and other naturally occurring soils. However, HAHT soils are now being recognized and classified in many soil classification systems at very high levels. A new soil order is proposed for U.S. Soil Taxonomy that would include the most obvious profoundly and intentionally altered HAHT soils. A discussion and justification is given for an unofficial proposal. Input will be collected from international groups of scientists, and modifications of the unofficial proposal are expected. The long-term result of establishing a new soil order will be to enable proper classification, allocation, and mapping of HAHT soils worldwide.     

Elemental and redox analysis of single bacterial cells by x-ray microbeam analysis

High-energy x-ray fluorescence measurements were used to make elemental maps and qualitative chemical analyses of individual Pseudomonas fluorescens strain NCIMB 11764 cells. Marked differences between planktonic and adhered cells were seen in the morphology, elemental composition, and sensitivity to Cr(VI) of hydrated cells at spatial scales of 150 nm. This technology can be applied to natural geomicrobiological systems.