مجال التميز | تميز دراسي وبحثي |
البحوث المنشورة |
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البحث (1): | |
عنوان البحث: | Determining the total energy budget of the tick Ixodes ricinus |
رابط إلى البحث: | https://link.springer.com/content/pdf/10.1007/s10493-020-00479-1.pdf |
تاريخ النشر: | 13/03/2020 |
موجز عن البحث: | Precise and accessible techniques for measuring metabolic responses to environmental stress are essential to allow the likely impacts of climate and climate change on tick distribution, abundance and phenology to be predicted. A more detailed understanding of the metabolic profile of ticks may also help the complex responses to pathogen infection and effects on transmission to be evaluated. Here, a series of biochemical protocols employing spectrophotometric methods are used to determine the entire energy budget of ticks. Protein, carbohydrate, total lipid, neutral lipid and glycogen were measured in individual Ixodes ricinus nymphs and adults. Two key trends were identified: in adults, protein was relatively more abundant than in nymphs, whereas in nymphs, glycogen and carbohydrate were more abundant than in adults, with glycogen alone composing 39% of the mass of metabolites in nymphs compared to 15 and 10% in females and males, respectively. The methods used were able to successfully separate neutral lipids from the polar phospholipids and the importance of distinguishing stored from structural lipid in estimates of lipid reserves is emphasised. The results demonstrate that the spectrophotometric approaches deliver relatively rapid and reliable estimates of the total energetic budget and can be used to quantify the metabolic profiles of individual ticks, demonstrating their suitability for use in ecological and epidemiological studies. |
البحث (2): | |
عنوان البحث: | Metabolic rate and resource depletion in the tick Ixodes ricinus in response to temperature |
رابط إلى البحث: | https://link.springer.com/article/10.1007/s10493-020-00568-1 |
تاريخ النشر: | 11/11/2020 |
موجز عن البحث: | Understanding the effects of temperature on the metabolic activity and the rate of depletion of energy reserves by Ixodes ricinus can represent an important contribution to explaining patterns of tick activity and the likely impacts of environmental change on tick and tick-borne disease risk. Here, a cohort of I. ricinus nymphs, males, and females was collected and placed into incubators at temperatures of between 5 and 30 °C. The protein, carbohydrate, total lipid, neutral lipid, and glycogen levels were measured for nymphs for up to 70 days and adults up to 42 days. In nymphs, at day 0, glycogen was the most abundant metabolite followed by carbohydrate, with relatively low concentrations of protein and lipids. For males, the concentrations of different metabolites were relatively similar. In contrast, for females, concentrations of glycogen and carbohydrate were relatively low compared to those of protein and neutral lipids. Significant exponential declines in metabolite concentrations of all metabolites were detected over time for all life-cycle stages and at all temperatures. Nymphs generally showed lower rates of resource depletion than adults at all temperatures. The lower thresholds for metabolic activity were estimated to be between −10 and −5 °C. The Q10 values, which describe the thermal sensitivity of metabolic rate, were estimated to be relatively low (1.5 for nymphs, 1.71 for males, and 1.63 for females) compared to insects where they are typically around 2.5 (range: 1.5–3), and this is considered to be an adaptation to increase survival during the extended inter-feed intervals. |
المؤتمرات العلمية |
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المؤتمر (1): | |
عنوان المؤتمر: | The British Society for Parasitology |
تاريخ الإنعقاد: | 15/04/2019 |
مكان الإنعقاد: | Manchester. UK |
طبيعة المشاركة: | Poster and Oral presentation |
عنوان المشاركة: | The metabolic energy budget of the tick Ixodes ricinus: effects of seasons |
ملخص المشاركة: | The work described in the currently is aimed to investigate the effects of temperature on the rate of depletion of energy reserves by nymphal and adult Ixodes ricinus. A cohort of nymphs, males and females were collected from the field, divided into groups and placed into incubators at temperatures of 5 °C, 10 °C, 15 °C, 20 °C, 25 °C and 30 °C. For nymphs the protein, the total water-soluble carbohydrates, total lipid, neutral lipid and glycogen levels were measured at days 0, 14, 28, 42, 56 and 70. For the adult males and females the measurements were performed only on days 0, 14, 28 and 42. In nymphs, the rate of soluble carbohydrates and glycogen utilisation was higher than in males or females and the concentrations of neutral lipids (a proxy for stored lipids) were significantly affected by higher temperatures (20-30 °C). In tick adults, the concentrations of protein and structural lipid (phospholipid) responded rapidly to changes in treatment time and the ambient temperature. |
المؤتمر (2): | |
عنوان المؤتمر: | The 27th Conference of the World Association for the Advancement of Parasitology Conference (WAAVP 2019) |
تاريخ الإنعقاد: | 11/07/2019 |
مكان الإنعقاد: | Wisconsin, United States |
طبيعة المشاركة: | Poster presentation |
عنوان المشاركة: | Spectrophotometric Analysis to Understand Ticks’ Nutrients and Behaviors |
ملخص المشاركة: |
The spread of tick-borne diseases in many parts of the world represents a significant health challenge for livestock and companion animals despite many advancements in the understanding of tick biology. Of crucial importance to the success of a tick species to reproduce and thrive in its specific environmental niche is the ability to efficiently obtain, store and metabolise the key bio-nutrients from their blood meal. Neither the metabolic requirements of developing ticks nor the allocation of resources to development have been studied extensively. Therefore, many aspects of tick physiology remain unclear. In the present work, a range of biochemical assays were used to estimate the seasonal patterns of free sugar (glucose), glycogen, lipid and protein accumulation through the life cycle of ticks in s.w. England. A total of 1.303 nymphs, males and females were analysed over the course of a year. The metabolic patterns observed provide a direct insight into the feeding history and life-history partitioning of resource during tick development. |
سعيد محمد ناصر الأسمري
دكتوراه
العلوم والتقنية
Bristol University