Living Mulch Establishment in Row Crop Systems for Sustainable Biofuels Production

With increasing removal of maize (Zea mays L.) stover for cellulosic biofuels or livestock bedding and feedstuffs, there exists a need to ensure natural resources-related issues such as soil erosion, nitrate leaching, and loss of organic matter content are appropriately managed. Perennial groundcover offers a tenable solution for alleviating these problems associated with maize stover removal from conventional cropping systems. We conducted a field study to ascertain the expected cost of perennial groundcover establishment on the primary crop of economic interest and groundcover success under a maize or soybean (Glycine max L.) crop. To test this concept, we established either Kentucky bluegrass (KB) (Poa pratensis L.) or creeping red fescue (CF) (Festuca rubra L.) as living mulch (LM) concurrently with either maize or soybean, documenting impacts on crop maturity, leaf area index (LAI), normalized difference vegetation index (NDVI), stand density, yield components, grain yield, and C and N. First-year maize and first- and second-year soybean in the no LM control yielded on average 13.00, 3.38, and 4.86 Mg ha-1, respectively, 30, 84, and 27% greater than LM systems. However, yield did not statistically significantly differ in the second site year between the no LM and LM maize. Moreover, perennial groundcover treatments did not affect expected ethanol yield in the second year, averaging 5,459 l ha-1 in year two over all treatments). These results indicate that further research is needed to achieve groundcover establishment and subsequent natural resources benefits in row crop production while minimizing impact on yield

Most \u3cem\u3eCaenorhabditis elegans\u3c/em\u3e MicroRNAs are Individually Not Essential for Development or Viability

MicroRNAs (miRNAs), a large class of short noncoding RNAs found in many plants and animals, often act to post-transcriptionally inhibit gene expression. We report the generation of deletion mutations in 87 miRNA genes in Caenorhabditis elegans, expanding the number of mutated miRNA genes to 95, or 83% of known C. elegans miRNAs. We find that the majority of miRNAs are not essential for the viability or development of C. elegans, and mutations in most miRNA genes do not result in grossly abnormal phenotypes. These observations are consistent with the hypothesis that there is significant functional redundancy among miRNAs or among gene pathways regulated by miRNAs. This study represents the first comprehensive genetic analysis of miRNA function in any organism and provides a unique, permanent resource for the systematic study of miRNAs

Living Mulch for Sustainable Maize Stover Biomass Harvest

The Renewable Fuels Standard mandate provides enhanced opportunity for maize (Zea mays L.) stover use as a bioenergy feedstock. Living mulch (LM) offers a possible solution for the natural resources constraints associated with maize stover biomass harvest. A two site-year study was conducted near Boone and Kanawha, IA, in both maize following maize (MM) and maize following soybean [Glycine max (L.) Merr.] (SM) sequences to evaluate the impact of established and chemically suppressed Kentucky bluegrass (Poa pratensis L.) (KB) ‘Ridgeline’, ‘Wild Horse’, ‘Oasis’, and ‘Mallard’ blend and creeping red fescue (Festuca rubra L.) (CF) ‘Boreal’ as LM on three maize hybrids (population sensitive, population insensitive, and yield stable). Maize grain yield for the no LM treatments in the MM and SM sequences was 12.0 and 13.2 Mg ha-1, respectively, at Boone and 12.8 and 14.8 Mg ha-1, respectively, at Kanawha, 23-73% greater than the LM treatment. Ethanol yield (L ha-1) was 12-119% greater, protein concentration was ≤9% greater, and starch concentration was ≤1% lower in the no LM treatment maize than LM treatment maize. Maize hybrid by cover interaction was significant for parameters including total aboveground biomass and protein concentration at Boone, with inconsistent maize hybrid responses to the LM system. Stover yield, stover quality, stover C and N, leaf area index (LAI), maize plant density, maize maturity, and sequence year in the MM sequence were also evaluated. Results emphasize the need for maize hybrid and LM system compatibility and effective LM suppression techniques

Weak seed-pairing stability and high target-site abundance decrease the proficiency of lsy-6 and other microRNAs

Most metazoan microRNAs (miRNAs) target many genes for repression, but the nematode lsy-6 miRNA is much less proficient. Here we show that the low proficiency of lsy-6 can be recapitulated in HeLa cells and that miR-23, a mammalian miRNA, also has low proficiency in these cells. Reporter results and array data indicate two properties of these miRNAs that impart low proficiency: their weak predicted seed-pairing stability (SPS) and their high target-site abundance (TA). These two properties also explain differential propensities of small interfering RNAs (siRNAs) to repress unintended targets. Using these insights, we expand the TargetScan tool for quantitatively predicting miRNA regulation (and siRNA off-targeting) to model differential miRNA (and siRNA) proficiencies, thereby improving prediction performance. We propose that siRNAs designed to have both weaker SPS and higher TA will have fewer off-targets without compromised on-target activity.National Institutes of Health (U.S.) (grant GM067031)Seoul National University (Research Settlement Fund)Howard Hughes Medical Institute (Investigator

Man versus Machine versus Ribozyme

A microfluidic device has been constructed to carry out the automated, continuous evolution of ribozymes. A comparison with manual efforts reveals that both are capable of far flung forays into sequence space

Perennial cover crop influences on soil C and N and maize productivity

New management systems are needed that enhance the sustainability of crop residue harvesting for use as feedstock in the emerging biofuel industry. We investigated whether a novel perennial cover crop management system, designed to overcome yield drag, would enhance sustainability of maize (Zea mays L.) residue harvesting. Overall the perennial cover crop treatments (Kentucky bluegrass (Poa pratensis L.) (BG) and creeping red fescue (Festuca rubra L.) (RF)) increased the soil potential mineralizable N (8.5 %), decreased the loss of total soil organic C (10.1 %) and N (6.5 %) relative to the no-cover crop controls (with (RR) and without (RS) removal of crop residues). Respired CO2, measured during 28 day incubations, decreased in the following order: RF\u3eRS≈BG\u3eRR for both in-row and in-between-row samples implying high microbial activity under cover crop treatments. SPAD readings, growth stage, and end of season maize-stalk nitrate test results varied by site-year but were consistent with soil NH4+/NO3- dynamics. Results indicate that competition between the maize and perennial cover crops for water and N resources was weather dependent. Although previous research documented that the management system employed was able to overcome the yield drag associated with perennial cover crops, in our study maize yields for the perennial cover crop treatments were only one third the yields for the controls. Overall, we conclude that the perennial cover crop system is capable of enhancing the sustainability of maize residue harvesting, but more work is needed to overcome the yield drag which may be caused by perennial cover crops under some conditions

Kempsey, New South Wales : How social and political divisions in Kempsey’s early history impacted the town’s economic and environmental development to 1865, and its ongoing susceptibility to disaster

This study addresses the question: how did social and political divisions influence the
 economic and environmental development of Kempsey during the colonial period up
 to 1865? Primary documents including personal letters, journals, memoirs, political
 and governmental papers, along with a range of colonial newspapers have been
 studied and interpreted to form a social historical solution to the question. Due to the
 range of sources available for this investigation, a variation of methodologies has been
 employed, with particular emphasis on an empirical qualitative analysis. In addition to
 considering existing non-scholarly thematic histories of the Macleay Valley, this
 thesis draws existing scholarly investigations together and builds upon them, looking
 into the interdependence between society and environment, politics and geographical
 developments, culture and social movements to piece together the story of Kempsey
 and uncover the key events which have led to long lasting impacts on the town. No
 other scholarly study of this kind has been undertaken to bring the entire complex and
 multifaceted story of Kempsey’s early years into one scholarly investigation.
 Implications for this study highlight the important factor that powerful social and
 political divisions in a community have when important decisions about town
 planning, environmental protection, and issues of social justice need to be addressed.
 These divisions can lead to catastrophic outcomes that could impact generations to
 follow, as shown in the tumultuous history of Kempsey, New South Wales

The influence of microRNAs and poly(A) tail length on endogenous mRNA–protein complexes

Background: All mRNAs are bound in vivo by proteins to form mRNA-protein complexes (mRNPs), but changes in the composition of mRNPs during posttranscriptional regulation remain largely unexplored. Here, we have analyzed, on a transcriptome-wide scale, how microRNA-mediated repression modulates the associations of the core mRNP components eIF4E, eIF4G, and PABP and of the decay factor DDX6 in human cells. Results: Despite the transient nature of repressed intermediates, we detect significant changes in mRNP composition, marked by dissociation of eIF4G and PABP, and by recruitment of DDX6. Furthermore, although poly(A)-tail length has been considered critical in post-transcriptional regulation, differences in steady-state tail length explain little of the variation in either PABP association or mRNP organization more generally. Instead, relative occupancy of core components correlates best with gene expression. Conclusions: These results indicate that posttranscriptional regulatory factors, such as microRNAs, influence the associations of PABP and other core factors, and do so without substantially affecting steady-state tail length.National Institutes of Health (U.S.) (Grant K99GM102319)National Institutes of Health (U.S.) (Grant T32GM007753)National Institutes of Health (U.S.) (Grant R01GM067031)National Institutes of Health (U.S.) (Grant R35GM118135)Natural Sciences and Engineering Research Council of Canada (Discovery Grant

Potential Role of miRNAs in Developmental Haemostasis

MicroRNAs (miRNAs) are an abundant class of small non-coding RNAs that are negative regulators in a crescent number of physiological and pathological processes. However, their role in haemostasis, a complex physiological process involving multitude of effectors, is just beginning to be characterized. We evaluated the changes of expression of miRNAs in livers of neonates (day one after birth) and adult mice by microarray and qRT-PCR trying to identify miRNAs that potentially may also be involved in the control of the dramatic change of hepatic haemostatic protein levels associated with this transition. Twenty one out of 41 miRNAs overexpressed in neonate mice have hepatic haemostatic mRNA as potential targets. Six of them identified by two in silico algorithms potentially bind the 3′UTR regions of F7, F9, F12, FXIIIB, PLG and SERPINC1 mRNA. Interestingly, miR-18a and miR-19b, overexpressed 5.4 and 8.2-fold respectively in neonates, have antithrombin, a key anti-coagulant with strong anti-angiogenic and anti-inflammatory roles, as a potential target. The levels of these two miRNAs inversely correlated with antithrombin mRNA levels during development (miR-19b: R = 0.81; p = 0.03; miR-18a: R = 0.91; p<0.001). These data suggest that miRNAs could be potential modulators of the haemostatic system involved in developmental haemostasis