36,155 research outputs found

    Suitability of the Pollen Grains, Ricinus communis and Helianthus annuus as Food for Six Species of Phytoseiid Mites (Acari: Phytoseiidae)

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    Laboratory studies were conducted on the acceptability of pollen grains of Ricinus communis (L.) and Helianthus annuus L. to Amblyseius zaheri Yousef and El-Borolossy, Euseius yousefi Zaher and El-Borolossy, Amblyseius lindquisti Schuster and Pritchard, Typhlodromus balanites El-Badry, Typhlodromus sennarensis El-Badry and Amblyseius cabonus (Schicha) as indicated by effect on development, survival, oviposition and life table parameters. A. zaheri and E. yousefi had a shorter developmental period on both pollen grains than A. lindquisti. Development was not completed in case of T. balanites, T. sennarensis and A. cabonus. A. zaheri and E. yousefi showed the highest oviposition rate when fed R. communis compared to H. annuus. A. lindquisti failed to lay any eggs when fed on both pollen grains. On both predator species, a diet of R. communis provided the shortest generation time (T) relatively, greatest female longevity and mean total fecundity (f) which resulted in the highest net reproductive rate (Ro) value (41.46 and 43.28 expected females per female), intrinsic rate of increase (rm = 0.279 and 0.258) and finite rate of increase (er m = 1.322 and 1.294 per day) for A. zaheri and E. yousefi respectively

    Impact of polyester and cotton microfibers on growth and sublethal biomarkers in juvenile mussels

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    Anthropogenic microfibres are a prevalent, persistent and globally distributed form of marine debris. Evidence of microfibre ingestion has been demonstrated in a range of organisms, including Mytilus spp. (mussels), but the extent of any impacts on these organisms are poorly understood. This study investigates, for the first time, the effect of exposing juvenile mussels to polyester and cotton microfibres at environmentally relevant concentrations (both current and predicted future scenarios) over a chronic timescale (94 days). Sublethal biomarkers included growth rate, respiration rate and clearance rate. Mussels were exposed to polyester (median length 149 µm) and cotton (median length 132 µm) microfibres in three treatments: polyester (~ 8 fibres L−1), polyester (~ 80 fibres L−1) and cotton (~ 80 fibres L−1). Mussels exposed to 80 polyester or cotton microfibres L−1 exhibited a decrease in growth rate of 35.6% (polyester) and 18.7% (cotton), with mussels exposed to ~ 80 polyester microfibres L−1 having a significantly lower growth rate than the control population (P < 0.05). This study demonstrates that polyester microfibres have the potential to adversely impact upon mussel growth rates in realistic future scenarios, which may have compounding effects throughout the marine ecosystem and implications for commercial viability

    Transcriptome sequencing reveals the effects of circRNA on testicular development and spermatogenesis in Qianbei Ma goats

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    Circular RNAs (circRNAs) play an important role in regulating the mammalian reproductive system, especially testicular development and spermatogenesis. However, their functions in testicular development and spermatogenesis in the Qianbei Ma goat, the Guizhou endemic breed are still unclear. In this study, tissue sectioning and circRNAs transcriptome analysis were conducted to compare the changes of morphology and circular RNAs gene expression profile at four different developmental stages (0Y, 0-month-old; 6Y, 6-month-old; 12Y, 12-month-old; 18Y, 18-month-old). The results showed that the circumferences and area of the seminiferous tubule gradually increased with age, and the lumen of the seminiferous tubule in the testis differentiated significantly. 12,784 circRNAs were detected from testicular tissues at four different developmental stages by RNA sequencing, and 8,140 DEcircRNAs (differentially expressed circRNAs) were found in 0Y vs. 6Y, 6Y vs. 12Y, 12Y vs. 18Y and 0Y vs. 18Y, 0Y vs. 12Y, 6Y vs. 18Y Functional enrichment analysis of the source genes showed that they were mainly enriched in testicular development and spermatogenesis. In addition, the miRNAs and mRNAs associated with DECircRNAs in 6 control groups were predicted by bioinformatics, and 81 highly expressed DECircRNAs and their associated miRNAs and mRNAs were selected to construct the ceRNA network. Through functional enrichment analysis of the target genes of circRNAs in the network, some candidate circRNAs related to testicular development and spermatogenesis were obtained. Such as circRNA_07172, circRNA_04859, circRNA_07832, circRNA_00032 and circRNA_07510. These results will help to reveal the mechanism of circRNAs in testicular development and spermatogenesis, and also provide some guidance for goat reproduction

    Shellfish Stocks and Fisheries Review 2022: an assessment of selected stocks

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    This review presents information on the status of selected shellfish stocks in Ireland. In addition, data on the fleet and landings of shellfish species (excluding Nephrops and mussels) are presented. The intention of this annual review is to present stock assessment and management advice for shellfisheries that may be subject to new management proposals or where scientific advice is required in relation to assessing the environmental impact of shellfish fisheries especially in areas designated under European Directives. The review reflects the recent work of the Marine Institute (MI) in the biological assessment of shellfish fisheries and their interaction with the environment. The information and advice presented here for shellfish is complementary to that presented in the MI Stock Book on demersal and pelagic fisheries. Separate treatment of shellfish is warranted as their biology and distribution, the assessment methods that can be applied to them and the system under which they are managed, all differ substantially to demersal and pelagic stocks. Shellfish stocks are not generally assessed by The International Council for the Exploration of the Sea (ICES) and although they come under the competency of the Common Fisheries Policy they are generally not regulated by EU TAC and in the main, other than crab and scallop, are distributed inside the national 12 nm fisheries limit. Management of these fisheries is within the competency of the Department of Agriculture, Food and Marine (DAFM). A co-operative management framework introduced by the Governing Department and BIM in 2005 (Anon 2005), and under which a number of fishery management plans were developed, was, in 2014, replaced by the National and Regional Inshore Fisheries Forums (NIFF, RIFFs). These bodies are consultative forums, the members of which are representative of the inshore fisheries sector and other stakeholder groups. The National forum (NIFF) provides a structure with which each of the regional forums can interact with each other and with the Marine Agencies, DAFM and the Minister. Management of oyster fisheries is the responsibility of The Department of Environment, Climate and Communications, implemented through Inland Fisheries Ireland (IFI). In many cases, however, management responsibility for oysters is devolved through Fishery Orders or Aquaculture licences to local co-operatives. The main customers for this review are DAFM, RIFFs, NIFF and other Departments and Authorities listed above.EMFAF; Government of Irelan

    Biological impacts of marine heatwaves

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    Climatic extremes are becoming increasingly common against a background trend of global warming. In the oceans, marine heatwaves (MHWs)—discrete periods of anomalously warm water—have intensified and become more frequent over the past century, impacting the integrity of marine ecosystems globally. We review and synthesize current understanding of MHW impacts at the individual, population, and community levels. We then examine how these impacts affect broader ecosystem services and discuss the current state of research on biological impacts of MHWs. Finally, we explore current and emergent approaches to predicting the occurrence and impacts of future events, along with adaptation and management approaches. With further increases in intensity and frequency projected for coming decades, MHWs are emerging as pervasive stressors to marine ecosystems globally. A deeper mechanistic understanding of their biological impacts is needed to better predict and adapt to increased MHW activity in the Anthropocene

    Relationship of Gonadotropin-Releasing Hormones (GnRH) Induction to Reproductive Performance in Batur Sheep

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    Experiments were performed to determine the relationship of Gonadotropin-Releasing Hormone (GnRH) induction to estrus activity and pregnancy rate of Batur sheep. Twenty Batur sheep were synchronized to estrus using intramuscularly injection of 2 ml PGF2α that repeated in 11-day intervals. GnRH was given intramuscularly on the 9th day for 10 Batur sheep, and 10 others were not injected as a control. Reproductive performance included estrus intensity, estrus onset, mating time period, and pregnancy rate. The data were analyzed by regression correlation tests, and chi-square test were used for pregnancy rate. The statistical analysis results showed that the induction of GnRH has a very significant relationship (P&lt;0.01) to the intensity and onset of estrus as well as the time-mating period it has a significant relationship (P&lt;0.05). The pregnancy rate was significantly different (P&lt;0.05) between control and GnRH-induced in Batur sheep. The results showed that GnRH induction contributed to the intensity of estrus, the onset of estrus, and the time-mating period of 37.88, 42.79, and 22.16%, respectively. The pregnancy rate in Batur sheep induced by GnRH compared to controls has 25.0% increased. It can conclude that GnRH induction was able to improve reproductive performance in Batur shee

    The effect of hypoxia on Daphnia magna performance and its associated microbial and bacterioplankton community: A scope for phenotypic plasticity and microbiome community interactions upon environmental stress?

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    The depletion of oxygen as a result of increased stratification and decreased oxygen solubility is one of the most significant chemical changes occurring in aquatic ecosystems as a result of global environmental change. Hence, more aquatic organisms will be exposed to hypoxic conditions over time. Deciphering the effects of hypoxia on strong ecological interactors in this ecosystem’s food web is critical for predicting how aquatic communities can respond to such an environmental disturbance. Here (sub-)lethal effects of hypoxia and whether these are genotype specific in Daphnia, a keystone species of freshwater ecosystems, are studied. This is especially relevant upon studying genetic responses with respect to phenotypic switches upon environmental stress. Further, we investigated the effect of hypoxia on the Daphnia microbial community to test if the microbiome plays a role in the phenotypic switch and tolerance to hypoxia. For this, two Daphnia genotypes were exposed for two weeks to either hypoxia or normoxia and host performance was monitored together with changes in the host associated and free-living microbial community after this period. We detected phenotypic plasticity for some of the tested Daphnia performance traits. The microbial community of the bacterioplankton and Daphnia associated microbial community responded via changes in species richness and community composition and structure. The latter response was different for the two genotypes suggesting that the microbiome plays an important role in phenotypic plasticity with respect to hypoxia tolerance in Daphnia, but further testing (e.g., through microbiome transplants) is needed to confirm this

    Recent advances using genetic analyses in waterhemp

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    Amaranthus tuberculatus (Moq.) Sauer is a driver weed species within maize and soybean production systems in the Midwestern United States. The development of herbicide resistance is a contributing factor leading to management challenges in the species. Recently, non-target-site herbicide resistance has been increasingly associated with new evolutionary events, further limiting the potential for effective herbicide programs to control the weed, leading to a need for new management options. Understanding the genetic diversity present within the A. tuberculatus gene pool, including for key traits such as non-target-site herbicide resistance and dioecy, may contribute to the advancement of effective management strategies. Inheritance, segregation, and linkage mapping of non-target-site resistance was conducted in two A. tuberculatus populations, one from Illinois and the other from Nebraska, to the Group 27 herbicide, tembotrione. Resistance in the two populations appeared to be derived from different evolutionary events, as it displayed dominant inheritance and multigenic segregation in the Nebraska population whereas it displayed additive, single-gene inheritance in the Illinois population. Genetic mapping was only successful for the Nebraska population, in which two quantitative trait loci (QTL) were identified. Candidate gene models associated with the dioecy trait were identified using two properties: uniqueness to the male-specific region and the presence of purifying selection. Of the 147 gene models predicted to be contained within the male-specific region, three fulfilled both filtering criteria: 00g213060, 00g213110 and 00g277460. GO-term enrichment analysis of the 1-Kbp proximal promoter region suggested that 00g213060 may prove interesting due to enrichment of terms associated with floral initiation and floral organ development. Hybridization studies and gene-flow experiments were conducted between A. tuberculatus and its close phylogenetic neighbor, A. arenicola. Under directed crosses, hybridization fecundity was comparable to those of intraspecific crosses. Results from pollen-competition experiments suggested that gene flow from A. tuberculatus to A. arenicola will occur frequently even in the presence of an intraspecific pollen donor. The studies described within this dissertation have made significant contributions to the understanding of non-target-site herbicide resistance, and the total genetic diversity of A. tuberculatus, both in the context of target traits such as dioecy and to the gene pool as a whole. Two QTL associated with resistance to a Group 27 herbicide were identified from a Nebraska A. tuberculatus population, and an Illinois population was determined to have evolved the trait independently. A single candidate gene model with a high likelihood to play a role in the dioecy trait was identified within the male-specific region of A. tuberculatus. Finally, I present evidence that A. arenicola may be within the primary gene pool of A. tuberculatus and could contribute to weedy adaptation in the species.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste

    The place where curses are manufactured : four poets of the Vietnam War

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    The Vietnam War was unique among American wars. To pinpoint its uniqueness, it was necessary to look for a non-American voice that would enable me to articulate its distinctiveness and explore the American character as observed by an Asian. Takeshi Kaiko proved to be most helpful. From his novel, Into a Black Sun, I was able to establish a working pair of 'bookends' from which to approach the poetry of Walter McDonald, Bruce Weigl, Basil T. Paquet and Steve Mason. Chapter One is devoted to those seemingly mismatched 'bookends,' Walt Whitman and General William C. Westmoreland, and their respective anthropocentric and technocentric visions of progress and the peculiarly American concept of the "open road" as they manifest themselves in Vietnam. In Chapter, Two, I analyze the war poems of Walter McDonald. As a pilot, writing primarily about flying, his poetry manifests General Westmoreland's technocentric vision of the 'road' as determined by and manifest through technology. Chapter Three focuses on the poems of Bruce Weigl. The poems analyzed portray the literal and metaphorical descent from the technocentric, 'numbed' distance of aerial warfare to the world of ground warfare, and the initiation of a 'fucking new guy,' who discovers the contours of the self's interior through a set of experiences that lead from from aerial insertion into the jungle to the degradation of burning human feces. Chapter Four, devoted to the thirteen poems of Basil T. Paquet, focuses on the continuation of the descent begun in Chapter Two. In his capacity as a medic, Paquet's entire body of poems details his quotidian tasks which entail tending the maimed, the mortally wounded and the dead. The final chapter deals with Steve Mason's JohnnY's Song, and his depiction of the plight of Vietnam veterans back in "The World" who are still trapped inside the interior landscape of their individual "ghettoes" of the soul created by their war-time experiences
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