SAFE MICROSCOPIC TECHNIQUES FOR AMATEURS Slide Mounting by Walter Dioni

Author:Walter Dioni [Dioni, Walter]
Language: eng
Format: epub
Published: 2014-06-01T07:00:00+00:00

CHAPTER 3A: Formulae Derived From Fructose FG—FructoseGlycerol Medium Brun’s medium was formulated to use glucose as the “sugar” ingredient. I have modified the formula to replace the glucose with fructose (in my case, Karo syrup).

Fructose at a 76% concentration 24 ml

Glycerol 3 ml

Antiseptic (I use Listerine) 3 ml

2

1 The first picture [1] shows the

surface of a fly wing, and the

second [2] the border of the

same. The picture [3] is from

the epithelium of the underside

of a leaf, showing one stomata

and the nuclei of two marginal

cells. The fourth (opposite

page) is the compound image

of the 5th leg from a female of

a species of Diaptomus, a

genus of copepod

(crustaceans). The sixth is the

ovisac (a sac in which the 3 female carries the eggs). All

were taken of slides mounted in

FG. The wings were stored in alcohol 70%. The epithelia was fixed for

5 24 hrs in AFA (a fi xative composed of Alcoh o l, Formalin, and Acetic acid) and the picture taken with the 100x object i v e (1000x), The copepods were fixed more than a month ago in lactocupric, a

fixative that I will discuss in a future article, and this specimen was washed in water for ten minutes and directly transferred to the mounting media. As we will see in other images, this is responsible for the collapse of the eggs. Some intermediate steps through glycerinated water can prevent this.

6

A modification that is also working for me is the addition of lactic acid as a clearing agent

FGL - Modified Brun’s medium Fructose (76% concentration) 21 ml Glycerol 3 ml Lactic acid 3 ml Antiseptic 3 ml

These two media, give good results with the test objects but take longer to dry. I estimate the drops so they don’t exceed the coverslip, and twenty four hours later I seal, with the same care as with a glycerin mountant. If not well sealed the coverslip continues to be "slippery" for more than a week.

The following images show examples. The first two [wing] & [epit] are similar to the FG pictures. The Diaptomus female in the third picture [ovisac] has adhered the ovisac, and also two spermatophores (sperm packets). Comments as in the FG case. The last three pictures are from a mosquito larva, fixed in alcohol 70% and first cleared in lactoglycerol, before being mounted in FGL. The head shows clearly the interior structure with the brain lobules, the nerves connecting to the eyes, several muscles and other sensitive organs. The ventral side of the head shows part of the buccal armature. The air tube is part of the caudal complex I depicted and labelled in the first article; you may wish to reread as a reminder of the anatomical features.

FGL, wing

FGL, epit FGL, ovisac

FGL, larva head FGL, telson setae

FGL, ventral head

Please refer to text for imageFGL, airtube

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