4,079 research outputs found
Foraging Effects of the Invasive Alien Fish Pterygoplichthys on Eggs and First-Feeding Fry of the Native Clarias macrocephalus in Thailand
No full textABSTRACT Native to Latin America, the sailfi n armored catfi sh Pterygoplichthys has been introduced to Thailand for the ornamental fi sh industry. This invasive species has fl ourished in nature and may threaten aquatic resources, especially of indigenous freshwater fi sh due to its foraging activities. This study investigated the biological impacts of the sailfi n armored catfi sh on the eggs and the fi rst-feeding fry of the Thai native catfi sh, Clarias macrocephalus that are found in similar habitats. The results showed that small, medium and large Pterygoplichthys fed on up to 95% or more of native catfi sh eggs within 24 hr. Pterygoplichthys also consumed the fi rst-feeding fry of C. macrocephalus. The average consumption of fi rst-feeding fry by small, medium and large Pterygoplichthys was 26.3±7.2, 71.8±23.5 and 86.3±13.7%, respectively. These results clearly indicated that the consumption of the catfi sh eggs was much higher than for the fi rst-feeding fry primarily due to the fact that the eggs were immobile and accessible. In addition, the consumption rates of fi rst-feeding fry by the armored catfi sh were positively correlated with the size of Pterygoplichthys (correlation coeffi cient = 0.6238, P < 0.01). In conclusion, Pterygoplichthys can destroy the eggs and fi rst-feeding fry of the native catfi sh Clarias macrocephalus and has the potential to reduce the populations of Thai native fi sh species
The transcription and notation of Elizabeth Fry's journal 1780-1845
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis proposes to explain the production of Fry's journal and make available to researchers a full transcription of the autobiographical journal of Elizabeth Fry. This journal tells Fry's life story in an episodic diary format that encapsulates the last forty-eight years of her life. The justification for the production of the transcription and the motivation behind It: The thesis will investigate the importance of Fry's Journal in the evolution of the diary genre. It will justify the huge undertaking entailed in making a full transcription of Fry's journal and will discuss the condition of the journal books and their different locations. How these factors contributed to the delay in producing a transcription earlier will be considered. What motivated Fry to write her journal and what influenced her to continue the process unabated for all her adult life? The reasons Fry had originally given for her journal production changed as her journal evolved and her life priorities changed. I will investigate the destruction of Fry's early journal books and her reasoning behind such editorial interference and her motivation for keeping others. Finally this section will close with an analysis of Fry's journal in order to establish what class within the diary genre it belongs. Dyslexia and its effect on Fry's journal text and the editorial procedures adopted: This part of this thesis discusses the indicators of dyslexia within the journal text and their
effect on the journal's production. I explain the resulting methodology adopted to alleviate the destructive effect that dyslexia had on the journal text. I have limited the editorial interventions undertaken when producing the transcription as I wished to maintain the integrity of Fry's journal. The final part of the thesis evaluates Fry's journal by making a
comparison with a contemporary journal. The journal I used for comparison was written by
Deborah Darby, a woman who shared many of Fry's life experiences. This thesis will
establish Fry's journal as belonging to that elite group of great diarists that includes Pepys. The appendices: these consist of a short biography of Fry with a published work explaining her role in the founding of modern nursing. A glossary of Quakers and the Gurney family terminology and finally a bibliography and the first two books, from Fry's journal with notes
Wellesly Sh. W. to Mr. James Meredith (2 October 1962)
No full textSigned by Wellesly Sh. W.https://egrove.olemiss.edu/mercorr_pro/1531/thumbnail.jp
The survey of vital condition on Sturgeon fry, when they were released into Tajan River by tagging
No full textThis Tajan river in / April/ 2000 and was followed to one year of Four stations selected from estuary to farah Abad station. Sampling occured to limited: (the survey of characteristic and choloride toxins in above limited in relative of three stations. Forty thousands species of Acipenser persicus fry with the different average weights were delivered fry were tagged and then the tagged fish were released in released stations in the different times. The fishing stations and the survival time in fry in the river, determination of upper and down streams in releasing area, Nutrition, Microbial diseases and estimation of catch populations in repeated fishing were evaluated. The physico - chemical characteristics of water and the evaluation of condamination were surveyed in the river. In addition, .the- evaluation of frequency and biomass (such as benthos and zooplankton were surveyed in the river). Finally, the effective factors in the mortality of fry in relative before and after releasing, the best place for releasing area of fry in the river was introduced into execution selection. The survival time of fry is low in the river and it depends on the distant between from the releasing area to estuary and the releasing time. Fry were passed from estuary after 24 hours and fry were approached to the sea after 48 hours and also the peak migration of them has been from 12 p.m to 3 a.m. The internal migrations don't have toward Upper River and these migrations have toward the sea. Fry haven't fed in survival time but after fourteen days, they caught in coastal section. The gammaridea and hypania (type of hypercilia) were fed by them. Before the releasing, fry have been contaminated by bacterial agents. The contamination rate was 3.3% but after releasing and passed from estuary have not been contaminated. The survey of the chemical and physical features in area indicated that the salinity was ascended higher than six ppt in third decade of April. The other factors indicated a healthy ecosystem. Of course, the increasing of salinity was related to Debi in water that approached to zero. The survey of choloride toxins in water indicated that were lack of difficult survey area in rivers. These toxins have been compared to another toxins such as hexa - choloro - benzen (a -HCB) that this concentration has a high in estuary. The evaluations the biomass of nutrition (Benthos and zooplankton) in the river indicated in the relative to benthic condition was included six classes. They contain bottom invertebrates, they have been identified 11 families and 9 species and so they consist of Insecta, Olighocheata class, Crustancea class, hypercilia class, Crustacea class, Bivalva class, Gastropoda class, it is obvious that the estuary station have a high biomass of benthic organisms and it has higher variation species than other stations. The zooplankton condition, In addition, it is belong to zooplankton that was identified to Rotatoria - Cladocera - Copepoda- Barnacles - Protozoa and forminofera as the beginning of spring season. Zooplanktons have a high variation but the end season, they have a below amount. Although, the gill net has one (cm) in mesh that sturgeon fry entrapped them the main effective factor of mortality about sturgeon's fry took place when sturgeon's fry entered into the sea. But the qoopegative company net of fishing, sturgeon's - fry caught in by catch that this agent were threatened when sturgeon's fry entered in to the sea. The evaluating of two stations for releasing the fry (research and farah Abad stations), the .research station (distance 500 m from estuary) has the best area for the releasing. the sturgeon's fry (fingerling) was introduced into the excution section . Key word Tajan river, Acipenser persicus (Sturgeon's fry gillnet) - nutrition, Microbal diseases, Choloride toxins.Iranian Fisheries Science Research InstitutePublishe
Histopathological effects and toxicity of atrazine herbicide in Caspian kutum, Rutilus frisii kutum, fry
No full textThis study aimed to investigate the toxic effects of atrazine herbicide on the fry of Caspian kutum (Rutilus frisii kutum, Kamensky, 1901). First the 96-h LC50 of the fry were exposed to atrazine at the concentration of 24.95 ppm was determined. Then the toxicity of this herbicide on Caspian kutum fry exposed to the concentration of 12.47ppm (1/2 LC50), for four days was measured and compared with a control group. Comparison of the length, weight and condition factor showed no significant differences between atrazine exposed and control group. The concentration of Na+, K+, Ca2+, Mg2+ and Cl- in the whole body of fry in control and atrazine exposure groups were as the following order: Ca2+>K+>Na+>Cl->Mg2+ and Ca2+>Na+>K+>Mg2+>Cl-, respectively. Results showed that the concentration of all these ions were higher in atrazine exposure group than control group, except for Cl-, and the only significant differences was found in Na+ concentration. Major histopathological effects of atrazine on the gills were hyperplasia and thickening of the filaments, separation of the pavement cells of the lamellae epithelium from the pillar cells and swelling of the epithelial cells. Results of the present study showed that atrazine could affect the ion composition of the body, and caused major damages in gill epithelium even at sublethal concentration and acute exposure, but had no effects on the growth parameters
Histopathological effects and toxicity of atrazine herbicide in Caspian Kutum, Rutilus frisii kutum, fry
No full textThis study aimed to investigate the toxic effects of atrazine herbicide on the fry of Caspian Kutum (Rutilus frisii kutum, Kamensky, 1901). First the 96-h LC50 of the fry were exposed to atrazine at the concentration of 24.95 ppm was determined. Then the toxicity of this herbicide on Caspian kutum fry exposed to the concentration of 12.47ppm (1/2 LC50), for four days was measured and compared with a control group. Comparison of the length, weight and condition factor showed no significant differences between atrazine exposed and control group. The concentration of Na+, K+, Ca2+, Mg2+ and Cl- in the whole body of fry in control and atrazine exposure groups were as the following order: Ca2+>K+> Na +> Cl- >Mg2+ and Ca2+>Na+>K+>Mg2+>Cl-, respectively. Results showed that the concentration of all these ions were higher in atrazine exposure group than control group, except for Cl-, and the only significant differences was found in Na+ concentration. Major histopathological effects of atrazine on the gills were hyperplasia and thickening of the filaments, separation of the pavement cells of the lamellae epithelium from the pillar cells and swelling of the epithelial cells. Results of the present study showed that atrazine could affect the ion composition of the body, and caused major damages in gill epithelium even at sublethal concentration and acute exposure, but had no effects on the growth parameters.Publishe
SMA-SH: Modified styrene maleic acid copolymer for functionalization of lipid nanodiscs
No full textChallenges in purification and subsequent functionalization of membrane proteins often complicate their biochemical and biophysical characterization. Purification of membrane proteins generally involves replacing the lipids surrounding the protein with detergent molecules, which can affect protein structure and function. Recently, it was shown that styrene–maleic acid copolymers (SMA) can dissolve integral membrane proteins from biological membranes into nanosized discs. Within these nanoparticles, proteins are embedded in a patch of their native lipid bilayer that is stabilized in solution by the amphipathic polymer that wraps the disc like a bracelet. This approach for detergent-free purification of membrane proteins has the potential to greatly simplify purification but does not facilitate conjugation of functional compounds to the membrane proteins. Often, such functionalization involves laborious preparation of protein variants and optimization of labeling procedures to ensure only minimal perturbation of the protein. Here, we present a strategy that circumvents several of these complications through modifying SMA by grafting the polymer with cysteamine. The reaction results in SMA that has solvent-exposed sulfhydrils (SMA-SH) and allows tuning of the coverage with SH groups. Size exclusion chromatography, dynamic light scattering, and transmission electron microscopy demonstrate that SMA-SH dissolves lipid bilayer membranes into lipid nanodiscs, just like SMA. In addition, we demonstrate that, just like SMA, SMA-SH solubilizes proteoliposomes into protein-loaded nanodiscs. We covalently modify SMA-SH-lipid nanodiscs using thiol-reactive derivatives of Alexa Fluor 488 and biotin. Thus, SMA-SH promises to simultaneously tackle challenges in purification and functionalization of membrane proteins.BN/Marie-Eve Aubin-Tam LabBN/Andreas Engel La
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The Effect of Temperature on the Survival of Chinook Eggs and Fry
No full textTemperature data from above and below the Cougar Dam collected by the U.S. Geological Survey prior to the construction of the temperature control structure was analyzed to determine how the di®ering temperature regimes a®ect the growth and survival of threatened spring- run Chinook salmon. An ARIMA time-series model was used to approximate each temperature record and a MATLAB program was written to simulate the growth of an individual Chinook salmon from egg to fry. Given a spawning distribution, the model was used to grow several hundred ¯sh in each temperature regime for a given period of time, and the distributions of ¯sh weights were recorded in histograms. The distributions of ¯sh weights above and below the dam were signi¯cantly di®erent (p < 0:001) and the temperature regime above the dam produced larger ¯sh than the temperature regime below the dam (p < 0:001). We conclude that the temperature regime below the dam (prior to the construction of the temperature control structure) is less conducive to the survival of Chinook than the temperature regime above
Omega-3 fatty acid eicospentaenoic acid attenuates MPP+-induced neurodegeneration in fully differentiated human SH- SY5Y and primary mesencephalic cells
No full textEicosapentaenoic acid ( EPA), a neuroactive omega-3 fatty acid, has been demonstrated to exert neuroprotective effects in experimental models of Parkinson's disease ( PD), but the cellular mechanisms of protection are unknown. Here, we studied the effects of EPA in fully differentiated human SH-SY5Y cells and primary mesencephalic neurons treated with MPP+. In both in-vitro models of PD, EPA attenuated an MPP+-induced reduction in cell viability. EPA also prevented the presence of electron-dense cytoplasmic inclusions in SH-SY5Y cells. Then, possible mechanisms of the neuroprotection were studied. In primary neurons, EPA attenuated an MPP+-induced increase in Tyrosine-related kinase B (TrkB) receptors. In SH-SY5Y cells, EPA down-regulated reactive oxygen species and nitric oxide. This antioxidant effect of EPA may have been mediated by its inhibition of neuronal NADPH oxidase and cyclo-oxygenase-2 ( COX-2), as MPP+ increased the expression of these enzymes. Furthermore, EPA prevented an increase in cytosolic phospholipase A2 ( cPLA2), an enzyme linked with COX-2 in the potentially pro-inflammatory arachidonic acid cascade. Lastly, EPA attenuated an increase in the bax:bcl-2 ratio, and cytochrome c release. However, EPA did not prevent mitochondrial enlargement or a decrease in mitochondrial membrane potential. This study demonstrated cellular mechanisms by which EPA provided neuroprotective effects in experimental P
Effects of Na Neutralization Level on the SH Behaviour after Ballistic Tests of EMAA Based Ionomers
No full textEthylene-co-methacrylic acid (EMAA) based ionomers have thermo-mechanical properties strongly dependent on neutralization level of acid groups. Research revealed also how these materials are able to heal after ballistic impacts. In order to better understand the role of neutralization level on the Self-Healing (SH) behaviour, mechanical and ballistic tests on EMAA copolymers, neutralized with different amount of Na ions, were performed in different experimental conditions. The SH capability was studied by shooting bullets at low velocity (180 m/s) and mid velocity (400 m/s); different testing conditions such as sample thickness and bullet diameter were examined. In all impact tests, spherical projectiles were used. These experiments allowed to define a critical ratio between sample thickness and bullet diameter below which the SH behaviour does not appear. After ballistic damage, the healing efficiency was evaluated by applying a pressure difference through tested samples. Subsequently, morphology analysis of the impacted areas was made observing all tested samples by Scanning Electron Microscope (SEM). These analysis revealed different characteristic features in the damaged zones of tested polymers impacted at different projectile speed. Obtained results show how the Na ions content influences the SH capability; in particular the EMAA copolymer with the highest Na neutralization level does not show a complete hole closure after low velocity impact test. Conversely, increasing projectile speed, all the polymers exhibit nearly the same SH behaviour
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