Water chemistry and nitrogen source affect foliar uptake efficiency in ‘champion’ bermudagrass

Abstract

Given the growing adoption and use of recycled irrigation across the turfgrass industry, there is importance in understanding the effects of irrigation chemistry on N uptake efficiency as it relates to various soluble N sources. The objective of this study was to determine interactive effects of three soluble N sources (ammonium sulfate, potassium nitrate, and urea) and three irrigation water sources (reverse osmosis (R.O.), sodic potable, and 2.5 dS m^?1 saline (SA)) on turfgrass performance and ¹⁵N nitrogen uptake efficiency following foliar N fertilization. Results demonstrated that although all water and N source treatments produced above-acceptable levels of quality in Champion bermudagrass, both N and water source significantly impacted nitrogen uptake efficiency. Following an eight-hour uptake period, approximately 40 to 70% of foliar-applied N (from a 0.5?g N m^?2 application) was recovered across all N sources. The highest uptake efficiency was noted with ammonium sulfate and urea treatments, with noticeably lower recoveries of N detected with potassium nitrate fertilization. Ammonium sulfate produced similar or improved turf quality to other N sources under R.O. and sodic potable irrigation, but reduced turf quality and green cover under saline irrigation. When water sources containing moderately high salinity levels (2.5 dS m^?1) are used, potassium nitrate (KNO₃) may provide the greatest turfgrass quality, however, its uptake efficiency may be lower than other N sources. The results suggest that soluble N source and tank mix and/or irrigation water chemistry may be important considerations for maximizing foliar uptake efficiency and minimizing potential for environmental loss.     

In situ Evidence for the Association of Total Coliforms and Escherichia coli with Suspended Inorganic Particles in an Australian Reservoir

The results of a field experiment that investigated the in situ association of total coliforms (TC) and E. coli (EC) with suspended inorganic particles in a drinking water reservoir are presented. The experimental program measured TC and EC at various locations and at multiple depths in a medium sized Australian reservoir subject to continuous inflow forcing. Particle concentrations and size distributions were measured using a LISST (Laser In Situ Scattering Transmissometer) profiler. Correlations between the particle measurements and the bacteria were calculated to provide in situ evidence for the association of TC and EC with suspended inorganic particles. Both TC and EC correlated most strongly with fine particles between 3.2 and 4.5 μm. Development of a simple Lagrangian model of the inflow for particles and microbes additionally provided insight into the relative roles of dilution, sedimentation, and inactivation for the bacteria. The model results and the correlations support the theory that high association with the small particles was due to their high number concentration and the effective surface area available for attachment. It was also evident that the majority of bacteria (> 80%) were physically associated with the suspended particles and allowed a quantitative estimate of the net sedimentation rate. Bacterial attachment and the concomitant increase in settling should be considered when modeling bacterial dynamics, during design of monitoring programs and when implementing pathogen risk management strategies.     

Companion animal preventive care at a veterinary teaching hospital — Knowledge,attitudes, and practices of clients

Preventive care is the cornerstone of health. However, veterinary staff to client (pet owner) communication of disease prevention may be limited resulting in increased pet risk. Our objectives were to evaluate knowledge, attitudes, and practices of clients regarding vaccination and parasite control and describe information sources influencing client preventive care. Over a 6-week period, clients visiting a veterinary teaching hospital in Prince Edward Island, Canada, were invited to complete a written questionnaire. Of those invited, 81% (105/129) completed the questionnaire. Respondents reported low (19 to 33%) to moderate (66 to 79%) coverage for canine “lifestyle” and core vaccines, respectively. Half of the participants reported that they had concern for their pet’s health from endo/ectoparasites compared to concern for their/household member’s health (27%), despite 45% reporting a person at increased zoonotic risk in their household. Veterinarians (89 to 92%) and online information (39 to 51%) were the highest client-reported resources for vaccine and parasite education. Our work provides a baseline for preventive care practices and highlights a need for improvement.     

Evaluation of biological and economic efficiency of the All Heifer,No Cow beef production system using a system dynamics model based on 6 yr of demonstration herd data

Alternative management strategies with no cows and all heifers may improve biological and economic efficiency of beef production. The All Heifer, No Cow (AHNC) beef production system involves insemination of nulliparous heifers with female sex-selected semen (FSS) to produce primarily female calves that are early weaned at 3 mo of age. Dams are finished on a high concentrate diet and harvested before 30 mo of age. The objectives of this research were to: 1) build a dynamic model of an AHNC beef production system to quantify system biological and economic efficiency; 2) compare effects of utilizing FSS vs. conventional semen on biological and economic efficiency; 3) evaluate what-if scenarios to determine the effects on biological and economic efficiency of changing variables ±5%, 10%, 15%, and 20% from initial observed values; and 4) evaluate the effects on biological and economic efficiency of changing variables ±10% from initial observed values. A model was built over a 21-yr horizon using Stella Architect. Biological parameter values in the model were based on the 6 yr of data collected from the management of an AHNC demonstration herd. In the model animal, total digestible nutrients (TDN) intake, hot carcass weight (HCW), and age at harvest were randomized. Feed, animal, and carcass prices included in the model were based on 10 yr of historical U.S. price data. Key response variables were biological and economic efficiency (mean ± SD). Biological efficiency was defined as the ratio of output (kilograms of HCW produced) to input (lifetime kilograms of feed TDN consumed), and economic efficiency was measured using a benefit–cost ratio (BCR) and unit variable cost (UVC). Over 40 simulation runs, the predicted mean biological efficiency was 0.0714 ± 0.0008. Economic efficiency was 0.95 ± 0.02 and US $445.41 ± 0.06 for BCR and UVC, respectively. Biological and economic efficiency was improved in the conventional semen scenario; biological efficiency was 0.0738 ± 0.0008, and BCR and UVC were 0.99 ± 0.04 and US $407.24 ± 0.006, respectively. Under this parameterization and market conditions, the AHNC beef production system failed to achieve profitability under any scenario that was evaluated. However, this review did not account for the potential increased genetic benefit from a decreased generation interval and the reduction in feed energy in comparison to a conventional cow/calf system.     

Efficient system of artificial oil bodies for functional expression and purification of recombinant nattokinase in Escherichia coli

Nattokinase, a serine protease, and pronattokinase, when expressed in Escherichia coli, formed insoluble aggregates without enzymatic activity. For functional expression and purification, nattokinase or pronattokinase was first overexpressed in E. coli as an insoluble recombinant protein linked to the C terminus of oleosin, a structural protein of seed oil bodies, by an intein fragment. Artificial oil bodies were reconstituted with triacylglycerol, phospholipid, and the insoluble recombinant protein thus formed. Soluble nattokinase was subsequently released through self-splicing of intein induced by temperature alteration, with the remaining oleosin-intein residing in oil bodies and the leading propeptide of pronattokinase, when present, spontaneously cleaved in the process. Active nattokinase with fibrinolytic activity was harvested by concentrating the supernatant. Nattokinase released from oleosin-intein-pronattokinase exhibited 5 times higher activity than that released from oleosin-intein-nattokinase, although the production yields were similar in both cases. Furthermore, active nattokinase could be harvested in the same system by fusing pronattokinase to the N terminus of oleosin via a different intein linker, with self-splicing induced by 1,4-dithiothreitol. These results have shown a great potential of this system for bacterial expression and purification of functional recombinant proteins.     

Local-scale diversity of Yersinia pestis: A case study from Ambohitromby,Ankazobe District,Madagascar

Plague is a re-emerging zoonotic disease and a major public health concern in several portions of the world, especially in Madagascar. We report on the presence of different subtypes of Yersinia pestis co-occurring in the same locality. After confirmation of a human plague case in Ambohitromby Commune (Ankazobe District) via isolation of Y. pestis, we undertook small mammal trapping to identify the circulation of Y. pestis amongst rodents in this locality; blood samples were collected from rodents for seroprevalence analysis. Of the 60 individuals of Rattus rattus captured, one yielded an isolate of Y. pestis, 13 others were positive for F1 antigen of Y. pestis using a rapid diagnostic test, and 4 were PCR positive targeting the caf1 and pla genes; 28/60 (46.7%) of the captured R. rattus were seropositive for Y. pestis. Whole-genome SNP analyses revealed that the two isolates obtained from the human case, and the R. rattus belonged to two different subtypes of Y. pestis (s05 and s13, respectively) that were circulating concurrently in Ambohitromby in 2016. Three Y. pestis subtypes (s03, s05 and s13) have now been isolated from Ambohitromby. Subtype s05 had been persisting there for >10 years but one or both of the other subtypes may have been introduced from the Central Highlands region as they were not observed in previous years (s13) or only observed once previously (s03). High seroprevalence against Y. pestis in R. rattus suggests that a portion of the local murine population may have acquired resistance to Y. pestis. Future research should focus on genomically characterizing Y. pestis strains circulating in Ankazobe District and other plague-endemic regions of Madagascar to better understand the overall phylogeography of Y. pestis.     

Whole-genome analysis of photosynthetic prokaryotes

The process of photosynthesis has had profound global-scale effects on Earth; however, its origin and evolution remain enigmatic. Here we report a whole-genome comparison of representatives from all five groups of photosynthetic prokaryotes and show that horizontal gene transfer has been pivotal in their evolution. Excluding a small number of orthologs that show congruent phylogenies, the genomes of these organisms represent mosaics of genes with very different evolutionary histories. We have also analyzed a subset of "photosynthesis-specific" genes that were elucidated through a differential genome comparison. Our results explain incoherencies in previous data-limited phylogenetic analyses of phototrophic bacteria and indicate that the core components of photosynthesis have been subject to lateral transfer.