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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Respiration rates and Factors which Influence the levels of Carbohydrates and Lipids in Honey Bee Eggs (<I>Apis mellifera </I>Linnaeus)

Mackasmiel, Lucas Aloyse Mugah 21 May 1999 (has links)
Respiration rates and changes in the amount of nutrients in queen-laid and worker-laid eggs of the honey bee, <I>Apis mellifera</I> L., were determined for the 3 days of embryonic development. Respiration was quantified by measuring the amount of CO₂ produced during 13 hr of artificial incubation at four temperature treatments: 28°C, 31°C, 34°C, 36°C (± 0.5°C). The amounts of lipids and carbohydrates were also quantified in the eggs of queens and laying workers on day 1, 2 and 3 using high performance thin layer chromatography. The mean respiration rate for fertilized and unfertilized eggs from queens was 0.1 ± 0.0 µL CO₂/hr/egg, the same as the mean respiration rate obtained for unfertilized eggs from laying workers. The results of carbohydrate analysis showed a total of 2.4 ± 0.6 µg/egg total sugars in the fertilized eggs of queens, an equivalent of 8.3% on a dry weight basis, while unfertilized eggs contained a total of 1.4 ± 0.4 µg/egg total sugars, equivalent of 6.3% on a dry weight basis. Total lipids, excluding fatty acids, were 10.7 ± 6.1 µg/egg (37.4%) for fertilized eggs and 8.4 ± 1.3 µg/egg (40.8%) for unfertilized eggs. The respiration rate at 34°C was 0.17 ± 0.01 µL CO<sub>2</sub>/hr/egg on day 1, the same as day 1 at 36°C. Day 2 respiration rates were 0.13 ± 0.04 µL CO₂/hr/egg and 0.15 ± 0.01 µL CO₂/hr/egg, respectively. On day three, 0.22 ± 0.01 µL CO₂/hr/egg was recorded at 34°C and 0.24 0.01 µL CO₂/hr/egg at 36°C. At low temperatures of 28°C and 31°C, a respiration rate of 0.12 ± 0.01 µL CO₂/hr/egg was recorded on day 1, for eggs held at both temperatures. Day 2 results were 0.07 ± 0.01 µL CO₂/hr/egg at 28°C and 0.11 ± 0.01 µL CO₂/hr/egg at 31°C, while 0.07 ± 0.01 and 0.12 ± 0.01 µL CO₂/hr/egg, respectively, were measured on day 3. Mortality results, as indicated by pre-emergence embryos, showed that 75% developed at 34°C compared to 37.5% at 36°C. Low temperatures of 28°C had 12.5% developing to pre-emergence stage while 50% developed at 31°C. Respiratory results showed significant differences (p=0.05) between the different days of incubation and temperature treatments, respectively. No significant difference was observed between the fertilized eggs and unfertilized eggs from queens at the same temperature treatment. The comparison of unfertilized eggs from queens and those from laying workers also showed no significant difference. The regression (R²=0.65) was significant (P=0.05) when CO₂ output on all the days and temperature treatments were compared. The amount of nutrients in the eggs of queens and those of laying workers, were significantly different (P=0.05) depending on egg type and age. No significant difference was observed between the colonies headed by queens or those of laying workers. Although the queen-laid eggs showed a relatively higher mean value for carbohydrates than worker-laid eggs, the reverse was the case for lipids. On comparing the amount of nutrients per unit weight for queen-laid and worker-laid eggs, no significant differences were observed. From the results obtained, inferences were made about the natural differences between the eggs from queens, and those produced by laying workers. / Master of Science
2

Minéralisation in situ de la matière organique le long de la colonne d'eau : application sur une station eulérienne.

Robert, Anne 26 September 2012 (has links)
Le cycle du carbone est régi principalement par les phénomènes de production et de reminéralisation de la matière organique le long de la colonne d'eau. Les acteurs principaux de cette reminéralisation sont les procaryotes hétérotrophes, dont les actions peuvent être mesurées sur l'ensemble de la colonne d'eau via la respiration procaryotique. Au cours de ce travail de thèse, un suivi à long terme et en temps réel des conditions hydrologiques et biogéochimiques (température potentielle, salinité et oxygène dissous, O2) a été mené entre 2008 et 2010 en Méditerranée Nord Occidentale, sur le site ANTARES. Ces observations ont permis de mettre en évidence les influences d'évènements ponctuels (convection hivernale d'eau profonde) par advection sur ces paramètres hydrologiques et biogéochimiques. Ces influences, directes ou indirectes, vont également avoir des incidences sur la concentration en matière organique et donc sur le potentiel reminéralisateur du milieu profond. Le suivi temporel de la concentration d'O2 a également permis de mettre en évidence une diminution de la concentration globale de 2.6 µmol O2 dm-3 a-1, sur une période de trois ans. Le développement au sein du laboratoire et en collaboration avec le Centre de Physique des Particules de Marseille (CPPM) d'un nouvel outil en équipression, le IODA6000 (In situ Oxygen Dynamics Autosampler), mesurant directement et à haute fréquence la dynamique de l'O2 a permis d'obtenir des vitesses de respiration procaryotique à 2000 m de profondeur depuis décembre 2009 sur le site ANTARES. / The carbon cycle is mostly driven by production and remineralisation processes which are constraining organic matter concentration along the water column. The main actors of the remineralisation are the heterotrophic prokaryotes, which actions can be measured from surface to deep by the prokaryotic respiration. During this PhD thesis, a long term real time monitoring of hydrological and biogeochemical conditions (potential temperature, salinity and dissolved oxygen O2) has been carried out between 2008 and 2010 in the North Occidental Mediterranean Sea, at the ANTARES site. Influence of punctual events has been observed which seem to be related to winter deep sea convection and subsequent advection, changing hydrological and biogeochemical properties observed at the ANTARES site. These direct or indirect modifications will have consequences on the organic matter concentration and therefore on the deep-sea remineralisation potential. The temporal monitoring of O2 concentration has also allow us to estimate the deep water oxygen consumption of 2.6 µmol O2 dm-3 a-1, during a three year period. The development in our laboratory in collaboration with Centre de Physique des Particules de Marseille (CPPM) of a new equipressured tool, the IODA6000 (In situ Oxygen Dynamics Autosampler), measuring directly and at high frequency the O2 concentration, allowed us to measure PR rates at 2000 m depth since December 2009 at the ANTARES site. This unique ongoing time series shows a mean prokaryotic respiration rates higher (0.2 µmol O2 dm-3 d-1) than expected by literature (5.5 10-3 µmol O2 dm-3 d-1), with a high temporal variability (from 8 10-3 to 0.5 µmol O2 dm-3 d-1).

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