Ontogeny of hepatic methionine catabolic enzyme activities (Transmethylation and Transsulphuration) and associated physiological amino acids in E10-21 chick embryos and D1-49 broilers

Developmental changes in hepatic methionine adenosyltransferase, cystathionine β-synthase, cystathionase, and glycine N-methyltransferase were determined in broiler chick embryos and hatched chicks by using radiometric and spectrometric methods. Hepatic free methionine, S-adenosylmethionine, S-adenosylhomocysteine, homocysteine, cystathionine, and cysteine levels were also investigated. Results showed an increase in hepatic MAT activity from E10 to E21 during embryogenesis, suggesting greater transmethylation rates throughout the rapid embryonic growth and development period. A strong positive correlation between embryo BW and MAT activity also supports this idea. The MAT specific activity continued to increase after hatching, but there was a negative correlation between chick BW and MAT activities from D1 to D49. This may indicate different MAT isozymes exist for chick embryo hepatic tissue compared to hepatic tissue of hatched chick and growing broilers. The developmental pattern of MAT isozymes could be critical for methionine metabolism to cope with the demand imposed on the embryo, chicks, and growing broilers. Additionally, the specific activity of hepatic CBS in chick embryos was determined to be lower compared to that observed in older broilers (35 and 49 days). Since liver CBS specific activity is at the lowest point from D1-7 in young chicks, the ability to convert adequate homocysteine to cysteine through transsulphuration may be limiting for cysteine synthesis at this time. Steady-state hepatic homocysteine levels in chick embryos and chicks may be a function of the rates of homocysteine formation, remethylation, and catabolism via the transsulphuration pathway. The present study indicates young chicks from D1 to D7 may have a limited ability for adequate transsulphuration; therefore, dietary cystine may be needed for optimum performance.     

Utilizing technology to enhance laboratory–client interaction while encouraging best behavior

As client interactions with veterinary diagnostic laboratories have evolved, so have client expectations: faster results, enhanced accessibility to cases, and more seamless data transfer from the laboratory database; all of these factors have encouraged the evolution of diagnostic laboratory systems. This evolution started with 24-h access to laboratory results via the web, yet data quality remained at the mercy of the person filling out the form. If bad (incomplete) information was flowing in, then the data coming out was equally bad (incomplete or inconsistent). By designing a web-based system integrated into our existing reporting platform, the Iowa State University Veterinary Diagnostic Laboratory (ISU-VDL) set out to improve the quality of submission data by including the premises identification number (PIN) and obtaining consistent location data, all while presenting to the client an easy-to-use interface. Efforts continued by incentivizing the use of this tool and client submission practices. As clients transitioned, data have become more complete, resulting in easier queries and an improved ability to leverage the diagnostic data. To further enhance the client experience, a streamlined daily reporting summary was designed to communicate laboratory results succinctly. The use of these web-based tools had a positive impact on the quality and consistency of the diagnostic data. As new ideas develop, the ISU-VDL strives to foster continuous improvement and positively impact the clients’ experience.     

Foliar damage to ornamental trees sprinkler-irrigated with reuse water

The extent of foliar damage to ornamental trees irrigated with treated sewage effluent (reuse water) may be a significant factor dictating the extent of reuse water implementation on golf courses, schools and parks in the arid southwestern United States. An experiment was conducted on 20 tree species to determine the extent of foliar damage when sprinkler-irrigated with reuse water, municipal water or a synthesized saline water. Irrigations (168) were applied over a 16-month period via 183-cm raised sprinkler heads, to plots that contained the trees in a dual-pot system. Plant water status, growth, tissue ion concentrations and an index of visual damage (IVD) were assessed at different times throughout the experiment. A higher IVD (greater foliar damage) was reported for most species when sprinkler-irrigated with either reuse or synthesized saline water. However, six species showed significant foliar damage even when irrigated with municipal water. The accumulation of Cl in the tissue was shown to be a species-dependent response, with tissue Cl concentrations varying by as much as a factor of 5. When a backward stepwise multiple regression analysis was conducted on the normalized (reuse-municipal) IVD and tissue ion concentrations, all ions except Na were eliminated from the correlation (Index (reuse - municipal)=0.79+0.62Na (reuse - municipal), r=0.72***, n=20). Wax content on the leaves in the reuse (0.310 mg cm^-2) and saline treatments (0.546 mg cm^-2) and the increase in wax content with time (young leaves/May vs mature leaves/July) suggested a possible stress response. Based on the results of this experiment, we believe the number of woody ornamental trees that can tolerate spray irrigation of reuse water in the hot dry environment of southern Nevada to be limited.     

Effect of phosphate-solubilizing bacteria and vesicular-arbuscular mycorrhizae on tomato growth and soil microbial activity

The interaction of vesicular-arbuscular mycorrhizae (VAM) and phosphate-solubilizing bacteria (PSB) on plant growth, soil microbial activities, and the production of organic acids was studied in non-sterile soil containing hydroxyapatite and glucose. Glomus etunicatum (VAM), a fungus, and Enterobacter agglomerans, a bacterium able to solubilize insoluble phosphate, were used as inocula. Three treatments and a control were used: inoculation with E. agglomerans (treatment E), inoculation with G. etunicatum (treatment G), inoculation with E. agglomerans+G. etunicatum (treatment E+G) and the control (C). Inoculation with E, G, or E+G had increased plant growth by days 35, 55, and 75 compared with the control. Microbial biomass carbon (C) and alkaline phosphatase activity in the rhizosphere generally increased with time. Alkaline phosphatase activity was higher in treatments G and E+G compared with the control at 35 and 55 days. The highest acid phosphatase activity was observed in treatment E at 35 days; however, this markedly decreased with time. A significantly higher soluble phosphorus (P) concentration was observed in treatments E and E+G on day 55 compared with C. However, there was no significant difference in soluble P concentration in the rhizosphere between treatments with time. The P concentration was greatest in all treatments on day 55. The highest oxalic acid concentration was observed in the rhizosphere of the non-sterile soil in E+G on day 35. Total N and P uptake in plants from treatments E and G were higher compared with the control. However, the highest N and P uptake was observed in treatment E+G. This study suggests a synergistic interaction between E. agglomerans and G. etunicatum. Received: 3 January 1997     

Solubilization of hydroxyapatite by Enterobacter agglomerans and cloned Escherichia coli in culture medium

Phosphate-solubilizing bacteria (PSB) possessing the ability to solubilize insoluble inorganic phosphate were isolated from the rhizosphere soil of wheat. A laboratory study was conducted to investigate the solubilization of phosphate by a known PSB, Enterobacter agglomerans, and by a genetically manipulated bacterium, Escherichia coli. A second laboratory study investigated the release of P from E. agglomerans compared with known acids. For the first laboratory study, a cosmid (pHC79) library of phosphate-solubilizing gene(s) from E. agglomerans chromosome DNA was constructed in E. coli JM109. The clone JM109 (pKKY) showing phosphate solubilization properties was screened on standard medium containing hydroxyapatite (HY). The P concentration significantly increased at 5 and 10 days for JM109 (pKKY) compared with JM109 (pHC79), the control. Although the P concentration increased, there was no significant change in their pHs. Furthermore, an increase in colony-forming units (CFUs) was seen at 5 and 10 days for JM109 (pKKY) but not for JM109 (pHC79). Artificial acidification of the culture medium with HCl, citric acid, oxalic acid, and lactic acid was achieved by shaking for 48h. Acidification with these selected acids solubilized more HY than E. agglomerans growing for 42h at similar pHs. However, a high P concentration was measured in culture medium with E. agglomerans growing for 84h despite similar pHs. Our results suggest that acid production may play an important role in HY solubilization, but is not the sole reason for the increase in P concentration in culture medium. Received: 12 February 1996     

Effect of management practices and cropping systems on earthworm abundance and microbial activity in Sanborn Field: a 115-year-old agricultural field

Sanborn Field, an agricultural demonstration field at the University of Missouri-Columbia, has over 100 years of cropping histories and management practices implemented at this site. We examined the effect of these cropping systems and management practices on earthworm populations and microbial activity. A field experiment was conducted to characterize and quantify earthworms and to determine the microbial activity in the same selected plots. We sampled 14 plots at the site, six of which were the original plots established in 1888 with the same cropping histories and management, and eight of which had been modified over the years to accommodate changing farmer needs and scientific questions. Earthworms and soil samples were collected in the spring and fall of 1999. Aporrectodea trapezoides, Aporrectodea caliginosa, and Lumbricus terrestris were the dominant species found in this field. Lumbricus terrestris was commonly associated with the no-tillage plot at Sanborn Field. Due partly to soil moisture conditions, most of the species were found and identified during the spring. Microbial activity, as expected, was greatest during the spring. Manure, no-tillage and crop rotations that include legumes had the greatest earthworm abundance and microbial activity. In general, where no fertility treatments were added to soil or where food sources were lacking, earthworm abundance decreased significantly. The abundance of earthworms found in this field reflected the cropping history and management practices used recently and within the last 100 years. In most cases, microbial activity showed similar trends as earthworm density. However, some dynamic microbial transformations, like nitrification, do not always follow the same trend as potential soil quality biotic indicators. Earthworms, along with microbial activity, may serve as useful soil quality indicators in sustained and short-term field trials.     

A comparison of badger activity in two areas of high and low bovine tuberculosis incidence of Northern Ireland

During 2005, a field survey of badger activity was carried out to evaluate differences between two areas with different levels of bovine tuberculosis (annual herd incidences of 16% and 4%) and to assess the awareness of herd keepers in relation to badgers. A random selection of herd keepers was interviewed and their farm land surveyed for the presence of badgers. The survey end point for each farm was the discovery of an active badger sett. Participation was very high in both areas (>80%). Evidence of badger activity was recorded on a higher proportion of farms in the area with a high tuberculosis herd incidence. However, when the difference in quality of agricultural land within each area was taken into account, a statistically significant association was not demonstrated. This suggests that the quality of agricultural land is a major determinant in the location of active badger setts. Nevertheless, the study did demonstrate the potential for increased exposure of cattle to badgers in the high incidence area. Herd keepers accurately identified the presence of badger setts on their land (positive predictive value=97%) but herd keepers reporting the absence of badger setts/activities on their land were found to be less accurate. Overall, the conclusions from this study tend to reflect the findings observed in other studies.