Aquatic Animal Diagnosis

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What is the purpose of decalcification in tissue preparation?

To facilitate infiltration with paraffin wax

To remove calcium ions from the tissue (correct)

To remove excess alcohol from the tissue

To make the tissue firm for sectioning

What is the ideal thickness of tissue sections for routine histopathological studies?

10-12 μm

15-20 μm

5-7 μm (correct)

3-5 μm

What is the primary function of xylene in tissue preparation?

Decalcification

Clearing (correct)

Impregnation

Dehydration

What is the ideal temperature for incubating culture plates for bacterial colonies?

25-30°C Signup and view all the answers

What is the optimal percentage of ethyl alcohol for dehydrating tissues?

50-70% Signup and view all the answers

What is the purpose of hematoxylin and eosin (H & E) staining?

To facilitate histological diagnosis of viral diseases Signup and view all the answers

What is the primary focus of the first level of diagnosis?

Physical examination and gross external features Signup and view all the answers

What is the ideal sample for diagnostic purposes?

Moribund fish Signup and view all the answers

What is the recommended volume of fixatives to be used for each specimen?

5-10 times the volume of the specimen Signup and view all the answers

What is the purpose of fixation of samples?

To preserve the sample for further analysis Signup and view all the answers

What is the recommended fixation time for 10% neutral buffered formalin (NBF)?

24h Signup and view all the answers

What is the name of the fixative that is best for shrimp histology?

Davidson’s Alcohol Formalin Acetic acid (AFA) Signup and view all the answers

What are the important gross external signs among finfishes?

Lesions, hemorrhage, color changes, fin erosion, fouling, bulging, and corneal eye opacity Signup and view all the answers

What is the purpose of archiving facilities in a laboratory?

To store test records and relevant data Signup and view all the answers

What is the color of the Gram - bacteria after Gram staining?

Red/Pink Signup and view all the answers

What is the indicator used in the oxidase test?

Indophenol blue Signup and view all the answers

What is the product of fermentation of glucose?

Lactic acid Signup and view all the answers

What is the purpose of the Voges-Proskauer test?

To detect the production of acetoin Signup and view all the answers

What is the principle of the catalase test?

To detect the presence of enzyme catalase Signup and view all the answers

What is the purpose of the nitrate reduction test?

To detect the reduction of nitrate to nitrite Signup and view all the answers

What is the principle of the ONPG test?

To detect the production of β-galactosidase Signup and view all the answers

What is the purpose of the Kirby-Bauer disc diffusion method?

To detect the presence of bacterial susceptibility Signup and view all the answers

What is the principle behind indirect immunofluorescence?

Using an unlabeled second antibody directed towards the first antibody Signup and view all the answers

What is the main application of ELISA?

To quantify the amount of antigen or antibody in a sample Signup and view all the answers

What is the main difference between direct and indirect immunofluorescence?

Direct immunofluorescence uses a fluorochrome-tagged primary antibody Signup and view all the answers

What is the purpose of bioassay?

To test for toxicity using living organisms Signup and view all the answers

What is the purpose of dot blot hybridization?

To detect the unfractionated DNA or RNA molecules fixed on a membrane Signup and view all the answers

What are the major components of PCR?

Primers, Target DNA, dNTPs, and Thermostable DNA polymerase Signup and view all the answers