Temperature and nutrient stoichiometry interactively modulate organic matter cycling in a pelagic algal-bacterial community

A microcosm experiment was conducted to investigate the interactive effects of rising sea-surface temperature and altered nutrient stoichiometry on the biogeochemical cycling of organic matter in a pelagic algal–bacterial assemblage. Natural seawater, containing a mixed bacterial community, was inoculated with an axenic culture of the bloom-forming diatom species Skeletonema costatum. A factorial combination of three temperatures, simulating weak to strong warming as projected for the end of the 21st century, and either nitrogen (N)-replete or -deficient growth conditions were applied. Depending on the type of nutrient limitation, the mixed algal–bacterial communities displayed pronounced differences in the accumulation and microbial utilization of organic matter in response to warming. Under N-deficient conditions, the build-up of organic matter occurred, irrespective of temperature, dominantly in the particulate pool, and only small amounts of dissolved material accumulated. The subsequent bacterial consumption of organic matter was low, as indicated by measurements of bacterial secondary production and extracellular enzyme activities, and remained also largely unaffected by an increase in temperature from 4°C up to 12°C. Contrastingly, warming resulted in a distinct temperature-dependent increase in the accumulation of dissolved organic carbon compounds under N-replete growth conditions. Moreover, rising temperature notably stimulated the bacterial activity, indicating an enhanced flow of organic matter through the microbial loop. These findings suggest that there will be strong shifts in the biogeochemical cycling of organic matter in the upper ocean in response to increased temperature and nutrient loading that will affect pelagic food-web structures and the biological sequestration of organic matter

The Disappearance of Moral Choice in Serially Reproduced Narratives

How do narratives influence moral decision-making? Our ongoing studies use serial reproduction of narratives, that is multiple retellings as in the telephone game, of morally ambiguous situations. In particular, we tested stories that include a minor misdemeanor, but leave open whether the wrongdoer will be punished by a bystander. It turns out that serial reproduction (retelling) of stories tends to eliminate the possibility of intervention by the bystander under certain conditions. We reason that this effect can be explained either by preferences of the readers or by the reader\u27s discomfort to get involved. A second finding is that retellings of third-person narratives of moral situations lead to a higher degree of change and invention of the outcome than first-person narratives

First Report of ‘CandidatusLiberibacter asiaticus’ Associated with Huanglongbing in Sweet Orange in Ethiopia

Huanglongbing (HLB) is a serious disease of citrus worldwide. Three different ‘Candidatus Liberibacter’ species are associated with HLB: ‘Ca. Liberibacter asiaticus’, ‘Ca. L. africanus’, and ‘Ca. L. americanus’ (1). ‘Ca. L. africanus’ and its vector, Trioza erytreae, are both heat sensitive, and when present, occur in citrus when temperatures remain below 30 to 32°C. In Africa, ‘Ca. L. africanus’ and T. erytreae have been reported in South Africa, Zimbabwe, Malawi, Burundi, Kenya, Somalia, Ethiopia, Cameroon, and Madagascar (1). Inspection of citrus trees in orchards and budwood sources in nurseries located in the warmer citrus-growing areas of Tigray and North Wollo in northern Ethiopia revealed nearly 100 trees with symptoms of leaf yellowing with a blotchy mottle pattern, dead branches, and decreased fruit quality and yield. Two symptomatic sweet orange budwood trees and three symptomatic orchard plants were sampled in April 2009, along with three healthy-looking sweet orange plants. DNA was extracted from 200 mg of desiccated leaf midribs using the CTAB method (4) and subjected to conventional PCR using the primer pairs A2/J5 (2) and OI2/23S1 (3) that amplify the ribosomal protein gene in the rplKAJL-rpoBC operon and the 16S/23S ribosomal intergenic regions, respectively, of ‘Ca. L. africanus’ and ‘Ca. L. asiaticus’. Positive PCR reactions were obtained for all five symptomatic samples with both primer pairs. PCR amplicons of 703 bp (A2/J5) and 892 bp (OI2/23S) recovered from two of these samples were purified, cloned, and sequenced. BLAST analysis revealed that the nucleotide sequences we obtained for the ribosomal protein (GenBank Accessions Nos. GQ890155 and GQ890156) shared 100% identity with each other and 99% identity with sequences of ‘Ca. L. asiaticus’ from Brazil (DQ471904), Indonesia (AB480161), China (DQ157277), and Florida (CP001677). Similarly, the 16S/23S ribosomal intergenic sequences (GU296538 and GU296539) shared 100% identity with each other and 99% identity with homologous ‘Ca. L. asiaticus’ sequences from Brazil (DQ471903), Indonesia (AB480102), China (DQ778016), and Florida (CP001677) and contained two tRNA genes as occurs in ‘Ca. L. asiaticus’ but not in ‘Ca. L. africanus’ (3). To our knowledge, this is the first report of ‘Ca. L. asiaticus’ in Africa. The presence of ‘Ca. L. asiaticus’ is a threat for warmer citrus-growing areas of Africa that are less favorable for ‘Ca. L. africanus’ and T. erytreae. In areas where ‘Ca. L. asiaticus’ was confirmed, symptomatic trees must be promptly eradicated and surveys to determine spread of the disease and its vectors are necessary

Site and Extent of Digestion of Finishing Diets Containing Syngenta Enhanced Feed Corn

Four ruminally and duodenally fistulated steers were utilized to evaluate the effects of Syngenta Enhanced Feed Corn™ containing an alpha amylase enzyme trait (SYT- EFC) compared to the isoline parental control corn without the alpha amylase enzyme trait (Negative Isoline) on site and extent of digestion in finishing diets. Cattle fed SYT- EFC dry rolled corn had numerically greater postruminal starch digestibility, excreted lower fecal starch, and had greater total tract starch digestibility compared to cattle fed Negative Isoline corn. These data would suggest that cattle are able to utilize more starch from corn containing the SYT- EFC trait, which has resulted in greater gains and efficiencies

Impact of Corn Silage Inclusion on Nutrient Digestion and Rumen Fermentation in Finishing Cattle

A digestion study was conducted comparing different inclusions of corn silage used as a roughage source on digestibility, feeding behavior and rumen environment. Treatments consisted of 3 inclusions of corn silage at 0, 7.5 and 15% of the diet DM, and a control treatment with 7.5% alfalfa. As expected, increasing available energy and decreasing roughage (either silage or alfalfa) showed an increase in diet digestibility and ruminal propionate concentrations. However, average ruminal pH was least, with more time spent in subacute acidosis (pH \u3c 5.3) when cattle were fed no roughage. These data suggest that feeding cattle increasing silage inclusions as a roughage source prevented ruminal conditions from entering and remaining in subacute acidosis. Feeding corn silage at 15% gave similar digestibility responses compared to 7.5% alfalfa. Including silage as a roughage source at 15% could help prevent acidosis and digestive upset in feedlot cattle

Impact of Syngenta Enogen Feed Corn on Finishing Cattle Performance and Carcass Characteristics

Two finishing experiments were conducted to evaluate Syngenta Enogen Feed Corn containing an alpha amylase enzyme trait compared to the near negative isoline control corn at two locations on cattle performance and carcass characteristics. No statistical differences were observed for final BW, DMI, ADG, or F:G for steers fed Syngenta Enogen Feed Corn versus the near negative isoline control corn. Fat depth and calculated yield grade were greater for steers fed Syngenta Enogen Feed Corn; however, HCW and marbling scores were not different. Previous research has observed a 2.6% to 16.4% decrease in F:G when Syngenta Enogen Feed Corn was fed; however, under this study a 1.6% reduction in F:G was observed

High-speed, high-resolution observations of shaped-charge jets undergoing particulation

Image-converter (IC) camera photography has provided spectacular images and quantitative records of liner collapse and early jet formation in shaped charges. We have extended the application of the IC camera to observations of shaped charge jet surfaces undergoing particulation. Sequential, high-resolution photographs were taken following the same 10-cm portion of jet at 2.5-{mu}s intervals. Simultaneous color rotating-mirror framing camera photographs and 450-keV flash x-ray radiographs were also taken of the same region. This combination provides a detailed record of the evolution of surface structure during jet necking and particulation. In the high-resolution photographs, individual features on the jet surfaces as small as {approximately}100 {mu}m can easily be detected and followed as they evolve over time. The jet surface structure is rough with overlapping slip dislocation lines running along the surface at 45{degree} to either side of the jet axis. This is similar to the texture that develops in long rods undergoing static tension. We discuss the implications of these images for increasing jet particulation times

Impact of Feeding Distillers Grains With or Without Oil Removal As Well As Supplemental Corn Oil on Nutrient Digestibility by Finishing Cattle

A digestion trial was conducted to determine the effects of the removal of corn oil from modified distillers grains plus solubles (MDGS) and the impact of supplemental corn oil on finishing cattle nutrient digestion. Four treatments were evaluated: a corn control diet (CON), 40% de-oiled MDGS (DO MDGS), or 38% de-oiled MDGS plus 2% corn oil (MDGS + Oil) formulated to equal the fat content of FF MDGS, or 40% full fat MDGS (FF MDGS). Treatment differences were observed for digestibility of dry matter, organic matter, and fiber, but not for fat. When oil was added to de-oiled MDGS, digestibility was decreased for dry matter, organic matter, and fiber when compared to de-oiled or full fat MDGS. Digestibility values from feeding DGS relative to corn control diets do not follow the same trend, digestible energy increases with DGS feeding, but OM digestibility decreases with DGS feeding

Effects of Syngenta Enogen Feed Corn containing an α-amylase trait on finishing cattle performance and carcass characteristics

Two experiments evaluated the effects of feeding a new corn hybrid, containing an α-amylase enzyme trait, Syngenta Enogen Feed Corn (SYT-EFC), on feedlot performance and carcass characteristics at two locations. Experiment 1 utilized 300 calffed steers (298.5 ± 16.3 kg of BW) at the University of Nebraska–Lincoln Eastern Nebraska Research and Extension Center Mead, NE. Treatments were designed as a 2 × 2 + 1– factorial arrangement with factors consisting of 1) corn type (SYT-EFC or conventional [CON]) and 2) byproduct type (with or without Sweet Bran [SB]), or a BLEND of STY-EFC and CON without SB. In Exp. 2, 240 crossbred, calf-fed steers (287.6 ± 15.4 kg of BW) were utilized at the University of Nebraska–Lincoln Panhandle Research and Extension Center near Scottsbluff, NE. Steers were fed SYT-EFC, CON, BLEND, or CON with a commercial α-amylase enzyme supplement (CON-E). In Exp. 1, there was an interaction for ADG (P = 0.05) and G:F (P = 0.02). Steers fed SYT-EFC with SB had greater ADG and G:F than CON; however, in diets without SB, SYT-EFC and CON were not different resulting in a 10.1% change in G:F when steers were fed SYT-EFC in SB compared with CON and only 1.6% change between SYT-EFC and CON without SB. Energy values, based on performance data, resulted in a 6.5% and 8.3% change in NEm and NEg, respectively, for steers fed SYT-EFC and CON with SB and 1.6% change for both NEm and NEg for steers fed SYT-EFC and CON without SB. For the main effect of corn trait, steers fed SYT-EFC had greater marbling scores, fat depth, and calculated yield grade compared with CON (P ≤ 0.03). In diets without SB, there was no difference between SYT-EFC, CON, or BLEND for DMI, final BW, ADG, G:F, NEm, or NEg (P ≥ 0.35). In Exp. 2, cattle fed SYT-EFC, BLEND, or CON-E had greater final BW, ADG, and G:F than cattle fed CON (P ≤ 0.03). On average, NEm and NEg were 4.9% and 7.0% greater, respectively, for steers fed amylase enzyme treatments compared with CON (P ≤ 0.01). Hot carcass weights were greater in steers fed α-amylase treatments compared with CON (P \u3c 0.01). Feeding Syngenta Enogen Feed Corn, which contains an α-amylase enzyme trait, at both locations improved feed efficiency in finishing cattle diets containing WDGS or SB

Evaluation of Protein from Distillers Grains in Finishing Diets on Nutrient Digestibility

A metabolism trial was conducted to evaluate protein from modified distillers grains plus solubles (MDGS) in finishing diets on nutrient digestibility and ruminal fermentation characteristics. Isolated protein from corn was not different than MDGS for dry matter, organic matter, or neutral detergent fiber digestibility. However, steers fed MDGS tended to have lower total tract organic matter digestibility compared to corn and protein from corn. Protein had greater total tract organic matter and starch digestibility than MDGS. Protein from corn did not contribute towards the lower digestibility of MDGS. Protein is more easily digestible than the other components in distillers grains plus solubles