Effect of dairy cow genotype and concentrate feed level on cow performance and enteric methane emissions during grazing

The current study (40 cows in a 2 × 2 factorial arrangement) compared methane (CH4) emissions from two dairy cow genotypes (Holstein-Friesian [HF], and Swedish Red × [Jersey × Holstein-Friesian] [Crossbred]) offered two levels of concentrate supplementation (3.0 or 6.0 kg/cow per day) while grazing. Enteric CH4 emissions were measured using the SF6 technique on three occasions over a 16 week period, while intakes were estimated using performance data. Increasing concentrate level increased milk and energy corrected milk (ECM) yields, had no effect on CH4 emissions (g day-1) and CH4 emissions per kg dry matter (DM) intake, while reducing CH4/ECM yield. Crossbreds produced milk with higher milk fat and protein contents than HF cows, but ECM yield did not differ between genotypes. Daily CH4 production (g day-1), and CH4 production per kg ECM yield was unaffected by genotype. Methane yield (g kg-1 DM intake) was higher with the Crossbred cows, although DM intake was estimated in this study, and this result should be interpreted with some caution. Thus HF and Crossbred cows had similar CH4 emissions

Identification by PCR signature-tagged mutagenesis of attenuated Salmonella Pullorum mutants and corresponding genes in a chicken embryo model

A key feature of the fowl-specific pathogen Salmonella Pullorum is its vertical transmission to progeny via the egg. In this study, PCR signature-tagged mutagenesis identified nine genes of a strain of S. Pullorum that contributed to survival in the chicken embryo during incubation. The genes were involved in invasion, cell division, metabolism and bacterial defence. The competition index in vivo and in vitro together with a virulence evaluation for chicken embryos of all nine mutant strains confirmed their attenuation

Innovative use of industrially produced steel slag powders in asphalt mixture to replace mineral fillers

Using steel slag to partially replace the natural aggregate in asphalt mixture to produce high-performance asphalt mixture has gained significant interest in recent years as a value-added option to recycle steel slag. However, the poor homogeneity of the material properties of steel slag aggregates remains a concern for this recycling approach. In this study, an innovative method of using industrially produced steel slag powder (SSP) to replace the mineral filler in asphalt mixture was proposed to address this concern. Five fillers, including four SSP fillers, obtained by grinding different steel slag aggregates with an industrialized production line, and one conventional limestone powder (LP) filler, were evaluated. The chemical compositions and micro-morphologies of the SSPs were first characterized to evaluate the material homogeneity and gain insights into the advantages of using SSPs as fillers. Then, asphalt mixtures with different fillers were designed and produced, and their moisture stability, rutting resistance, and low-temperature crack resistance, were characterized. It was found that the industrially produced SSPs possessed homogeneous properties, and improved the compatibility between filler particles and asphalt binder. Besides, the asphalt mixtures with SSP fillers showed better resistance to the moisture damage, permanent deformation, low-temperature crack in terms of fracture energy, than the asphalt mixture with LP filler. Therefore, it was concluded that using SSPs as a replacement of mineral fillers in asphalt mixture provided a reliable and value-added solution to recycle steel slag

Measurements of methane emissions and energy and nitrogen utilisation for quantifying the carbon footprint of young Holstein cattle

The desire to develop national greenhouse gas (OHO) emission inventories and mitigation strategies to reduce carbon footprint of cattle production systems, has prompted interest to fill the knowledge gap of OHO emission from young cattle in the UK. The current UK government funded study was undertaken over a two-year period to evaluate the effects of gender (steers vs. heifers) of growing Holstein cattle (6 to 22 months of age) on enteric methane emissions and energy and nitrogen utilisation and then to use these data to develop prediction models for quantification of carbon footprint of the dairy production sector. Twenty 5-month old Holstein cattle (10 steers and 10 heifers) were used in successive 28 d feeding period, with measurements undertaken at age of 6, 12, 18 and 22 months, to investigate the effects on feed intake, live weight gain, energy and nitrogen (N) utilisation and enteric methane (CH4) emission. Throughout the study, cattle were offered a diet for ad libitum intake containing a single perennial ryegrass silage mixed with concentrates. In the first period, the concentrate supplement was offered at a ratio of 550 g/kg of dry matter (DM), while it was given at a fixed rate of 2 kg DM daily in other 3 periods. During each measurement period, the cattle were housed as a single group in cubicle accommodation for the first 20 d, then individually in metabolism units for the next 3 d, and then in indirect open-circuit respiration calorimeter chambers for the final 5 d with feed intake, faeces and urine outputs and gaseous exchange measured during the last 4 d.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The Molecular Mechanism of Ethylene-Mediated Root Hair Development Induced by Phosphate Starvation

<div><p>Enhanced root hair production, which increases the root surface area for nutrient uptake, is a typical adaptive response of plants to phosphate (Pi) starvation. Although previous studies have shown that ethylene plays an important role in root hair development induced by Pi starvation, the underlying molecular mechanism is not understood. In this work, we characterized an <i>Arabidopsis</i> mutant, <i>hps5</i>, that displays constitutive ethylene responses and increased sensitivity to Pi starvation due to a mutation in the ethylene receptor ERS1. <i>hps5</i> accumulates high levels of EIN3 protein, a key transcription factor involved in the ethylene signaling pathway, under both Pi sufficiency and deficiency. Pi starvation also increases the accumulation of EIN3 protein. Combined molecular, genetic, and genomic analyses identified a group of genes that affect root hair development by regulating cell wall modifications. The expression of these genes is induced by Pi starvation and is enhanced in the <i>EIN3</i>-overexpressing line. In contrast, the induction of these genes by Pi starvation is suppressed in <i>ein3</i> and <i>ein3eil1</i> mutants. EIN3 protein can directly bind to the promoter of these genes, some of which are also the immediate targets of RSL4, a key transcription factor that regulates root hair development. Based on these results, we propose that under normal growth conditions, the level of ethylene is low in root cells; a group of key transcription factors, including RSL4 and its homologs, trigger the transcription of their target genes to promote root hair development; Pi starvation increases the levels of the protein EIN3, which directly binds to the promoters of the genes targeted by RSL4 and its homologs and further increase their transcription, resulting in the enhanced production of root hairs. This model not only explains how ethylene mediates root hair responses to Pi starvation, but may provide a general mechanism for how ethylene regulates root hair development under both stress and non-stress conditions.</p></div

The dominant-negative effect of the <i>hps5</i> mutation.

<p>(A), Morphology of 7-day-old seedlings of the WT, <i>hps5</i>, and three <i>35S</i>::<i>mERS1</i> transgenic lines grown on P+ and P- media. (B), A close view of the root tips of the seedlings in (A). In (A) and (B), the numbers at the top are the names of the transgenic lines.</p

ChIP-qPCR assays of the binding of the EIN3 to the promoters of ten selected genes.

<p>Chromatins from the WT and <i>35S</i>::<i>EIN3-GFP</i> transgenic plants were isolated and immuno-precipitated with GFP-Trap. The levels of enrichment of the precipitated DNA fragments were quantified by qPCR assays. An actin gene fragment was amplified as the internal control. Values are means ± SD of three replicates. Experiments were repeated two times with similar results. Asterisks indicate a significant difference from the WT (<i>t</i>-test, P < 0.05).</p

Accumulation of EIN3 protein in WT, <i>hps5</i>, and ACC-treated seedlings grown under P+ and P- conditions.

<p>(A) Western blot analysis of EIN3 proteins in WT and <i>hps5</i> seedlings. (B) Western blot analysis of EIN3 proteins in WT plants treated or not treated with 10 μM ACC. In (A) and (B), the antibodies raised against native EIN3 protein were used. The proteins extracted from the seedlings of the <i>EIN3 OX</i> line were used as the positive control of EIN3 protein. (C) Confocal analysis of the accumulation of EIN3-GFP in the root tips of 7-day-old <i>35S</i>::<i>EIN3-GFP</i> seedlings grown under various conditions.</p