104 research outputs found
A Histological Assessment of the Reproductive Cycle of the Sea Urchin, Lytechinus variegatus
The regular echinoid Lytechinus variegatus is a valuable model for the study of early embryological development. Lytechinus variegatus inhabits nearshore seagrass beds in the Gulf of Mexico and Caribbean, and the species ranges from the Carolinas along the US Atlantic coast to Brazil. Evaluating the natural reproductive cycle of L. variegatus will aid in understanding its role in community structure and in the management of this resource when housed in the laboratory. From April 2001 to September 2003, at intervals of 4—6 weeks, L. variegatus (41−50 mm diameter; n = 32 individuals/collection) were collected at Eagle Harbor in St. Joseph’s Bay, FL. A histological staging system for gamete development and maturation of the gonad was devised for female and male L. variegatus. The annual minimum gonad index was observed in September or October and increased to a maximum in March or April. A period of nutrient storage and limited gametogenic activity along the germinal epithelium in the fall and winter preceded spring gamete production and maturation. Observations of the mature reproductive stage in L. variegatus were associated with the new and full moon, suggesting that lunar cycle or tides influenced the timing of spawning. Peak periods of spawning occurred in spring and, occasionally, in the summer. Spawning probably did not occur from October to January. These data indicate field collections can be timed for early spring to ensure gravid adults for developmental studies
Effect of Temperature on Gamete Production and Biochemical Composition of Gonads in the Sea Urchin Lytechinus variegatus
Temperature is one of the most important proximate factors affecting the biology of ectothermal organisms. In the sea urchin, Lytechimus variegatus, the reproductive cycle in wild populations is correlated with changing water temperature, suggesting that reproduction may be dependent, in part, on temperature. Adult L. variegatus (ca. 35.63 ± 1.24 g wet weight, 40-mm diameter) were collected in October 2001 from St. Joseph Bay, FL (30°N, 85.5°W) and transported to the University of Alabama at Birmingham. Sea urchins were placed into nine 80-liter aquaria (n = eight sea urchins per aquarium) maintained in enclosed incubators (n = three aquaria per incubator) at a specific constant temperature of 16, 22, or 28°C and 32 ppt salinity synthetic seawater (Instant Ocean). Within each aquarium, individuals were maintained in 1-liter containers with recirculation and were fed daily a formulated feed ad libitum for 8 wk. At the end of week 8, final measurements of each individual were recorded, individuals were dissected, gonads were measured, and gonad histology and biochemistry were analyzed. Gonad weights were highest for individuals held at the 22°C treatment, but did not vary between individuals held at 16 or 28°C. The acinus volume in the gonad was occupied primarily by nutritive phagocytes at all temperature treatments. In females, gamete volumes were highest for females held at 22°C, whereas gamete volumes were not different for females held at 16 or 28°C. In males, gamete volumes were significantly lower at 28°C, and gamete volumes were not different between males held at 16 or 22°C. Gamete volumes were small in all temperature treatments, suggesting that gamete production had not substantially advanced within the 8-wk study period. The cellular ultrastructure of the nutritive phagocytes varied with temperature. Vacuolated nutritive phagocytes were common in the acini of individuals held at 16°C, and globulated nutritive phagocytes were common in the acini of individuals held at 28°C, Females held at 22°C had the highest protein content in the gonad, and protein content was not different between females held at 16 or 28°C. The amount of lipid was highest for males held at 16°C and did not differ between males held at 22 or 28°C. These data lead us to suggest that L. variegatus utilize different nutrient allocation strategies in the gonad in response to temperature, which could affect the reproductive success of the species if subjected to long-term changes in seawater temperature
The changing landscape of conservation science funding in the United States
To understand the changing role of funding sources in shaping conservation science in the United States, we analyzed acknowledgments from published studies, trends in research funding, and survey responses from conservation scientists. Although the U.S. federal government was the most frequently acknowledged source of support overall, U.S. foundations and NGOs were the predominant sources for tropical and socioeconomic research. Acknowledgments of foundation support for conservation research increased over the last two decades, while recognition of federal funds declined. Concordant trends in funding and acknowledgments indicated a changing landscape for conservation science, in which federal support has not kept pace with the growth in conservation research efforts or needs. Survey responses from conservation scientists about their funding sources were consistent with acknowledgment data, and most (64%) indicated that shifts in funding sources and amounts affected the type of research they conduct. Ongoing changes in the funding landscape shape the direction of conservation research and may make conservation science more vulnerable to economic recessions
Forest carbon emissions from cropland expansion in the Brazilian Cerrado biome.
Abstract. Land use, land use change, and forestry accounted for two-thirds of Brazil?s greenhouse gas emissions profile in 2005. Amazon deforestation has declined by more than 80% over the past decade, yet Brazil?s forests extend beyond the Amazon biome. Rapid expansion of cropland in the neighboring Cerrado biome has the potential to undermine climate mitigation efforts if emissions from dry forest and woodland conversion negate some of the benefits of avoided Amazon deforestation. Here, we used satellite data on cropland expansion, forest cover, and vegetation carbon stocks to estimate annual gross forest carbon emissions from cropland expansion in the Cerrado biome. Nearly half of the Cerrado met Brazil?s definition of forest cover in 2000 (?0.5 ha with ?10% canopy cover). In areas of established crop production, conversion of both forest and non-forest Cerrado formations for cropland declined during 2003?2013. However, forest carbon emissions from cropland expansion increased over the past decade in Matopiba, a new frontier of agricultural production that includes portions of Maranhão, Tocantins, Piauí, and Bahia states. Gross carbon emissions from cropland expansion in the Cerrado averaged 16.28 Tg C yr1 between 2003 and 2013, with forest-to-cropland conversion accounting for 29% of emissions. The fraction of forest carbon emissions from Matopiba was much higher; between 2010?2013, large-scale cropland conversion in Matopiba contributed 45% of total Cerrado forest carbon emissions. Carbon emissions from Cerrado-tocropland transitions offset 5%?7% of the avoided emissions from reduced Amazon deforestation rates during 2011?2013. Comprehensive national estimates of forest carbon fluxes, including all biomes, are critical to detect cross-biome leakage within countries and achieve climate mitigation targets to reduce emissions from land use, land use change, and forestry
Benefits of calorie restriction in mice are mediated via energy imbalance, not absolute energy or protein intake
We thank Jifeng Huang and Xuemei Cao for their assistance with mouse care and data collection, the UAB Small Animal Phenotyping Core for body composition and indirect calorimetry measures, and the UAB Metabolism Core for hormone and metabolite assessments. We also acknowledge and thank the Biological Services Unit staff in Aberdeen for their help with animal care in facilities at the University of Aberdeen.Peer reviewe
Do UK universities communicate their brands effectively through their websites?
This paper attempts to explore the effectiveness of UK universities’ websites. The area of branding in higher education has received increasing academic investigation, but little work has researched how universities demonstrate their brand promises through their websites. The quest to differentiate through branding can be challenging in the university context, however. It is argued that those institutions that have a strong distinctive image will be in a better position to face a changing future. Employing a multistage methodology, the web pages of twenty UK universities were investigated by using a combination of content and multivariable analysis. Results indicated ‘traditional values’ such as teaching and research were often well communicated in terms of online brand but ‘emotional values’ like social responsibility and the universities’ environments were less consistently communicated, despite their increased topicality. It is therefore suggested that emotional values may offer a basis for possible future online differentiation
Womens satisfaction with their breast prosthesis: What determines a quality prosthesis
The aim of this study is to determine what factors constitute a quality prosthesis and ascertain which factors affect prosthesis satisfaction. Sixty-four women who received full funding for their prosthesis and 38 women who received their hospital’s usual fundingwere recruited. Women rated the information provided about breast prostheses very highly, with 85% reporting that it was "very good" or "excellent." Satisfaction was significantly associatedwith how well the prosthesis fit (1 week,p=.001; 3 months,p=.01), level of comfort (3 months,p=.005), and appearance of the prosthesis when worn (6 months,p = .001). Quality was significantly associated with how well it fit (1 week,p = .001; 3months,p = .001), how natural it felt (1 week,p = .001; 6months,p=.01), the weight of the prosthesis (3 months,p=.003), and appearance when worn (6 months,p = .03). The results will be used to improve women’s access to a quality prosthesis. <br /
Characterization of the Viral Microbiome in Patients with Severe Lower Respiratory Tract Infections, Using Metagenomic Sequencing
The human respiratory tract is heavily exposed to microorganisms. Viral respiratory tract pathogens, like RSV, influenza and rhinoviruses cause major morbidity and mortality from respiratory tract disease. Furthermore, as viruses have limited means of transmission, viruses that cause pathogenicity in other tissues may be transmitted through the respiratory tract. It is therefore important to chart the human virome in this compartment. We have studied nasopharyngeal aspirate samples submitted to the Karolinska University Laboratory, Stockholm, Sweden from March 2004 to May 2005 for diagnosis of respiratory tract infections. We have used a metagenomic sequencing strategy to characterize viruses, as this provides the most unbiased view of the samples. Virus enrichment followed by 454 sequencing resulted in totally 703,790 reads and 110,931 of these were found to be of viral origin by using an automated classification pipeline. The snapshot of the respiratory tract virome of these 210 patients revealed 39 species and many more strains of viruses. Most of the viral sequences were classified into one of three major families; Paramyxoviridae, Picornaviridae or Orthomyxoviridae. The study also identified one novel type of Rhinovirus C, and identified a number of previously undescribed viral genetic fragments of unknown origin
An HLA-E-targeted TCR bispecific molecule redirects T cell immunity against Mycobacterium tuberculosis
Peptides presented by HLA - E, a molecule with very limited polymorphism, represent attractive targets for T cell receptor (TCR) - based immunotherapies to circumvent the limitations imposed by the high polymorphism of classical HLA genes in the human population. Here, we describe a TCR - based bispecific molecule that potently and selectively binds HLA - E in complex with a peptide encoded by the inhA gene of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis in humans. We reveal the biophysical and structural bases underpinning the potency and specificity of this molecule and demonstrate its ability to redirect polyclonal T cells to target HLA - E - expressing cells transduced with mycobacterial inhA as well as primary cells infected with virulent Mtb. Additionally, we demonstrate elimination of Mtb - infected cells and reduction of intracellular Mtb growth. Our study suggests an approach to enhance host T cell immunity against Mtb and provides proof of principle for an innovative TCR - based therapeutic strategy overcoming HLA polymorphism and therefore applicable to a broader patient population
Nutrient intakes and nutritional biomarkers in pregnant adolescents: a systematic review of studies in developed countries
Background: Babies born to adolescent mothers have been shown to have poorer outcomes compared to those born to adults. Nutritional status may have an important role to play in improving the health of pregnant adolescents; however there is a lack of evidence regarding the adequacy of adolescent diets during pregnancy. This systematic review aims to examine what is known about the nutritional status of adolescent pregnant women. Methods: A systematic search of the literature identified 21 studies which met the inclusion criteria for the review. Primary research papers using any methods were included where they were published in English between January 1995 and May 2015 and included measurements of nutrient intakes or biological markers of nutritional status in pregnant women aged 11-19 years. Individual study data was first summarised narratively before study means were pooled to give an estimate of nutritional status in the population. Results: The results show that individual studies reported intakes of energy, fibre and a number of key micronutrients which were below recommended levels. Biological markers of iron and selenium status also showed cause for concern. Pooled analysis of individual means as a percentage of UK Dietary Reference Intakes showed intakes of vitamin D (34.8 % CI 0-83.1) to be significantly below recommendations (p=0.05). Serum selenium levels were also found to be low (61.8 μg/L, CI 39-84). Conclusions: This review has identified a number of areas where the nutritional status of pregnant adolescents is sub-optimal, which may have implications for the health of adolescent mothers and their babies. It was not however possible to examine the impact of supplement use or socio-demographic characteristics which limits the interpretation these results. Further work is needed to establish the characteristics of those most at risk within this population, how this differs from adult pregnant women and the role of supplementation in achieving adequate nutrition
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