In vivo time-lapse imaging of the retina in the developing zebrafish (Danio rerio)

Digitisation of this thesis was sponsored by Arcadia Fund, a charitable fund of Lisbet Rausing and Peter Baldwin

In Vivo Time-Lapse Imaging of Cell Divisions during Neurogenesis in the Developing Zebrafish Retina

AbstractTwo-photon excitation microscopy was used to reconstruct cell divisions in living zebrafish embryonic retinas. Contrary to proposed models for vertebrate asymmetric divisions, no apico-basal cell divisions take place in the zebrafish retina during the generation of postmitotic neurons. However, a surprising shift in the orientation of cell division from central-peripheral to circumferential occurs within the plane of the ventricular surface. In the sonic you (syu) and lakritz (lak) mutants, the shift from central-peripheral to circumferential divisions is absent or delayed, correlating with the delay in neuronal differentiation and neurogenesis in these mutants. The reconstructions here show that mitotic cells always remain in contact with the opposite basal surface by means of a thin basal process that can be inherited asymmetrically

Photocatalytic Activation and Reduction of CO2 to CH4 over Single Phase Nano Cu3SnS4::A Combined Experimental and Theoretical Study

In view of their ability to absorb visible light and their high surface catalytic activity, metal sulfides are rapidly emerging as promising candidates for CO 2 photoreduction, scoring over the traditional oxide-based systems. However, their low conversion efficiencies due to serious radiative recombination issues and poor stability restrict their real-life applicability. Enhancing their performance by coupling them with other semiconductor-based photocatalysts or precious noble metals as cocatalysts makes the process cost intensive. Herein, we report the single-phase ternary sulfide Cu 3SnS 4 (CTS) as a robust visible-light photocatalyst for selective photoreduction of CO 2 to CH 4. It showed a remarkable 80% selectivity for CH 4 evolution with the rate of 14 μmol/g/h, without addition of any cocatalyst or scavenger. The mechanistic pathway for catalytic activity is elucidated by first principle calculations and in situ ATR, which imply a formaldehyde pathway of hydrocarbon production. The Cu-Sn termination of the surface is shown to be the key factor for competent CO 2 absorption and activation as confirmed from our X-ray spectroscopy measurements and first principle calculations. This study provides a foundation and insights for the rational design of sulfide-based photocatalysts to produce renewable fuel. </p

Hypolipidemic activity of Coriandrum sativum in diabetic dyslipidemic rats

Background: Metabolic syndrome is described as the clustering of obesity, aberrant glucose metabolism, dyslipidemia and hypertension. A characteristic pattern, termed diabetic dyslipidemia, consists of low HDL, increased triglycerides and postprandial lipemia. This pattern is most frequently seen in type 2 diabetes and may be a treatable risk factor for subsequent cardiovascular disease. This study was designed to compare the hypolipidemic activity of Coriandrum sativum L. with the standard antidiabetic drug, metformin in streptozotocin induced diabetic rats.Methods: Streptozotocin (STZ) was used to induce diabetes in the rats. The hypolipidemic activity of Coriandrum sativum seed extract was compared to the standard drug metformin. 4 groups (n=8) (normal control, diabetic control, streptozotocin+Coriandrum sativum and streptozotocin+metformin). The drugs were administered once daily for 28 days following which lipid profile was estimated on 28th day by using blood sample collected from the retro-orbital space.Results: STZ induced diabetes and also lead to dyslipidemia. Oral administration of CS seed extracts significantly lowered total cholesterol (TC), LDL:HDL ratio, TC:HDL ratio, thus, reducing the cardiovascular risk. HDL levels were slightly increased with CS seed extract compared to diabetic control group but not statistically significant. There was also statistically insignificant reduction in the atherogenic index with CS seed extract compared to diabetic control.Conclusions: CS seed extract (40 mg/kg) orally may have considerable therapeutic benefit as a hypolipidemic agent and can be suggested as a potential dietary add on

Antidiabetic activity of Coriandrum sativum in streptozotocin induced diabetic rats

Background: Diabetes mellitus (DM) can be defined as chronic hyperglycemia due to lack in insulin secretion and/or action. This study was designed to compare the antidiabetic activity of Coriandrum sativum L. with the standard antidiabetic drug, Metformin in Streptozotocin induced diabetic rats.Methods: Streptozotocin (STZ) was used to induce diabetes in the rats. Standard drug was metformin and test drug were Coriandrum sativum seed extract. 4 groups of 8 rats each were taken (normal control, diabetic control, streptozotocin + Coriandrum sativum and streptozotocin + metformin). Blood Sugar Levels (BSL) and HbA1C levels were estimated on day 0, 14 and 28 and day 28 respectively.Results: Streptozotocin administration resulted in significant rise in BSL. This rise was reduced with the administration of CS seed extract, but the reduction was more with chronic administration. It also reduced the HbA1C levels but couldn’t attain total normoglycemia. However, the reduction of BSL was superior with Metformin compared to the test drug.Conclusions: Oral administration of Coriandrum sativum seed extract at a dose of 40 mg/kg has shown antihyperglycemic activity in streptozotocin induced diabetic rats. Thus, Coriandrum sativum may have considerable therapeutic benefit as an antidiabetic agent and can be suggested as a potential dietary add on

A study to evaluate the analgesic activity of Origanum vulgare in mice using hot plate method

Background: The International Association for Study of pain, has defined pain as actual or potential tissue damage or described in terms of such damage. But the burden of unwanted side effects with current regimens are high. To explore the potential of Ayurveda drugs, this study is done by using Origanum vulgare.Methods: In vivo model used-Hot plate method. Origanum vulgare (84 mg/kg p.o) was administered in mice. The analgesic activity was studied by recording the reaction time after administration of the drug at frequent intervals up to 3 hrs. The results were analysed by ANOVA and Tukey’s test. P value <0.05 was considered as significant. Pentazocine showed statistically prolongation in the reaction time after 30 min as compared to Origanum vulgare.Results: In hot plate method, pentazocine showed statistically significant increase in the reaction time after 30 min of administration as compared to control group. However, Origanum vulgare in a dose of 84 mg/kg showed significantly increase in the reaction time after 30 min of administration as compared to control group. On comparing pentazocine and Origanum vulgare, pentazocine showed highly significant increase in the reaction time after 30 min as compared to Origanum vulgare at 84 mg/kg dose.Conclusions: From the present study, it was concluded that extract of Origanum vulgare exerted analgesic activity in both the models. However, it was less potent than pentazocine. Thus, Origanum vulgare can be used in mild to moderate painful conditions

A study to evaluate the analgesic activity of Origanum vulgare in mice using tail flick method

Background: Pain is a complex experience consisting of physiological and psychological response to a noxious stimulus. Analgesics like opiates and non-steroidal anti-inflammatory drugs are commonly used for relieving pain but are associated with various unwanted side effects; therefore this study was conducted by using Origanum vulgare for their analgesic efficacy.Methods: In vivo model used was tail flick method. Origanum vulgare (84 mg/kg p.o) was administered in mice. The analgesic activity was studied by recording the reaction time after administration of the drug at frequent intervals up to 3 hours. The results were analysed by ANOVA and Tukey’s test. P-value <0.05 was considered as significant. Pentazocine showed statistically prolongation in the reaction time after 30 min as compared to Origanum vulgare.Results: In tail flick method, pentazocine showed statistically significant increase in the reaction time after 30 min of administration as compared to control group. However, Origanum vulgare in a dose of 84 mg/kg showed significant increase in the reaction time after 30 min of administration as compared to control group. On comparing pentazocine and Origanum vulgare, pentazocine showed highly significant increase in the reaction time after 30 min as compared to Origanum vulgare at 84 mg/kg dose.Conclusions: From the present study, it was concluded that extract of Origanum vulgare exerted analgesic activity in both the models. However, it was less potent than pentazocine. Thus, Origanum vulgare can be used in mild to moderate painful conditions