Tardigrades are water-dwelling, eight-legged, segmented micro-animals. They were first discovered by the German zoologist Johann August Ephraim Goeze in 1773. The name Tardigrada was given three years later by the Italian biologist Lazzaro Spallanzani. They have been found everywhere: from mountain tops to the deep sea and mud volcanoes (Wikipedia).
Tardigrades, often called water bears or moss piglets, are near-microscopic animals with long, plump bodies and scrunched-up heads. They have eight legs, and hands with four to eight claws on each. While strangely cute, these tiny animals are almost indestructible and can even survive in outer space. Tardigrade is a phylum, a high-level scientific category of animal. (Humans belong in the Chordate phylum — animals with spinal cords.) There are over 1,000 known species within Tardigrade. Water bears can live just about anywhere. They prefer to live in sediment at the bottom of a lake, on moist pieces of moss or other wet environments. They can survive a wide range of temperatures and situations (https://www.livescience.com/57985-tardigrade-facts.html)
I went looking for tardigrades today in St Michael’s church graveyard in Lichfield, Staffordshire, UK. No success – sadly – so you won’t see tardigrades in the photo and video below. However, the samples I obtained from moss on gravestones, some lichen off trees and a sample from a wood chipping pile, revealed a range of life shown in the video below.
Vorticella on a commercial stained slide, viewed using Zeiss IM microscope at different magnifications. Damian and I have previously seen Vorticella live in local pond water samples – see previous posts.
I used the Bresser MikOkular camera in “new” trinocular head (second hand from ebay) – this differs from previous trinocular head in that this is the one that is recommended in the Zeiss IM microscope handbook. I noted that the previous head, although it works, has small black ring around outside of field of view that I assume means field stop is too small for scope. This new one does not have this. This new one also provides 23mm ocular attachment on trinocular port, into which the Diagnostic Instruments adapter fits directly without needing a clamp.
I also tried out a dark field condenser on microscope today – did not work well – not sure why – so photos below are back to the phase condenser that came with the microscope, used without phase annulus (i.e. in bright field mode).
x63 objective (slide upside down so light only has to go through coverslip in this inverted microscope – 63x objective has only limited working distance). This is a panorama of 17 panes, joined using Microsoft’s Image Composite Editor:
This is where the epi-illumination technique comes into its own. The following pictures are of a UK 1£ coin – showing up surface relief differences and tiny scratches that are not otherwise visible to naked eye.
I have used the white balance adjust function in the Bresser MikroCamLabII software (camera control software) to remove the effect of the colour tinge imparted by the mirror in the filter cube on the microscope.
Following photos x4 objective:
Helicon Focus stack – interestingly this does not appear to have improved a great deal on above best focus image:
The following images are taken on the Zeiss IM microscope using epi-illumination with the Zeiss 46 63 01 – 9901 filter cube from which I removed the filters. They show the effect of the coloured semi-silvered mirrors that remain in situ – these are required to direct the light and without them the microscope would not provide epi-illumination. Perhaps I can exchange them for non-pigmented mirrors in future?
Human-skin-commercial-slide-x20-obj-Kholer-illum-red-mirror-190218I.png – comparison image to above – same field of view – shows that epi-illumination is low contrast compared to transmitted light, particularly on this type of specimen. I have read similar in an article on Micscape website:
Comparison image of Aspergillus via transmitted light:
The following picture is a photo composite created from a video that goes through focus using Helicon Focus stacking software – this allows the best bits of focus at different levels to be combined:
I have purchased a spare second hand polarising filter cube. The Zeiss IM microscope (similar to IM35) uses an epi-illumination system for epi-fluorescence. However it was not designed with simple bright-light epi-illumination in mind. I am hoping that I can adapt this filter cube to allow me to introduce epi-illumination in bright-field on this scope.
My first step is to remove the fluorescence filters from the cube. These are extremely expensive filters so I want to ensure that I keep them carefully and know where to put them back if I wish to put the cube back to normal. Removal of the filters is very easy – a plastic ring holds them in and is very simple to remove.
I have 3 of these filter cubes. I am not sure if they have same filters or not so I have taken photos below during removal of the filters from this cube in order that I know how to replace them in the future.
List of filters included on filter cube:
The following pictures show the cube with the filters in situ, before removal:
Removal of filters from the cube:
The two filters at front (one each side) have labels on each filter. The following photos show the labels on those filters:
After filters are removed, it is possible to see the semi-silvered mirrors within the filter cube. The following pictures show that these are them selves coloured. I do not know how this will affect epi-illumination. They may removal too much light for effective epi-illumination and therefore require replacement or allow enough light that I can leave them in situ. I can easily see through them by eye allow they do give colour tinge to view:
I was very excited to obtain a second hand trinocular head for my Zeiss IM microscope. However, when I took the phototube off the head, I wasxshocked to find it rusted inside- this was on both the phototube and head where they attached to each other.
The picture below shows the rust on the head. The good news is that this is the only place with rust. I took the head apart and there is no rust inside. So, I guess moisture has just got into this bit which was made of unprotected steel. The sellers are unlikely to have known it was there as I doubt they ever had reason to take the phototube off the head.
My wife suggested I do some research on the internet to find out the best way to remove this rust. I came up with italic acid as a particularly powerful rust remover, although with warnings to open windows due to the fumes. This sounded like the beasty I needed so I ordered some from the all-encomposing ebay. It arrived last week so I had a go this weekend at using it to remove the rust.
I started with phototube. This is just a simple metal tube so there are no optics to ruin. I prepared the italic acid solution – a few teaspoons in hot water stirred with an ice lolly stick (I did not want acid to ruin our household spoons!) I then prepared a shallow glass container of the acid (I did not know whether the acid would burn through plastic although I suspect it would be OK as the italic acid crystals were sent in a plastic container).
The following picture shows the container plus the amazing result of sitting the phototube is the acid for only a couple of minutes. The rust just disappeared as if by magic! Immrsion in this acid is very effective. A good wash under the tap followed to wash off the acid then 30 minutes in the oven at very low temperature to dry it out thoroughly so it did not immediately rust again. A light covering oil finished the job.