Except when noted otherwise, the included images are personal pictures obtained with a digital camera of 0.4 Mpx. integrated into my National Optical DC3-163-P microscope equipped with planachromatic optics. (Ocular 10x, Objectives: x4 (NA 0.10), x10 (NA 0.25), x40 (NA 0.65) and x100 HI (NA 1.25)). The original ones have been captured at 640 x 480 px. and reduced or trimmed as was necessary to include them in this work. All picture formatting work was made in Photo Paint. In each picture's legend the objective upon which it was taken is indicated, just as a suggestion of the power used. The widest illustration in this page is 960 pixels, half width pictures, are therefore 460 pixels, which correspond to the real size of a 640 px. picture.

Pseudoscorpion, arthropod from the litter, mounted in PVA-G; excellent photomicrography kindly communicated by Mike André, one of my North American correspondents.

The amateur microscopist likes to explore the micro-world of fresh or marine waters. The diversity and beauty of the species that populate them are enough to captivate their interest for many hours that generally would be extended to days, months, or years.

This is the world of free living creatures, which move at will in the medium in which they live, even though they often crawl or glide over live or inanimate substrata. To explore those diverse habitats can be an infinite occupation, and it is normally the first task that the amateur assigns himself.

A few examples of free living aquatic organisms are included below.

Naidid oligocheta of free life - x4, blue toning	Macrostomum, a turbellaria of free life - x4 Oblique Illumination

Marine Nematode, ovoviviparous, of the psammon of a beach of "Isla mujeres", Cancún; the image is a mosaic composed with photos taken with the objective 10x, original size 1933 x 825 pixels.

A heliozoan, x100, bright field	Rotifer of the genus Philodina, x40, Rheinberg filter, blue center, yellow periphery

A Cladocera of the family Chydoridae, mosaic of 8 images, x10, bright field. It lives between the floating plants.	Copepod of the Cyclopidae family, mosaic of 12 images, x 10, common inhabitant of plankton.

But living species have developed diverse styles of life, in addition to free life.

Some (many) of those aquatic species live fixed to a substrate, they are sedentary, adhering to stones and other animated or inanimate substrates.

Collotheca, rotifer sessile, x10, bright field,  from a pool in a plant garden at  Cancún.	Tokophrya, protozoa, with sucking tentacles, x100, bright field. Three images amalgamated with CombineZ 3.0, from a brackish water aquarium, Cancún.	Stentor muelleri, x40, bright field from a brackish water aquarium, Cancún.

Others are even associated to other species (algae for example) without causing any damage to them. Although they cannot be considered "free", they are yet independent beings. They need the live substrate only for a support.

There are the epiphytes (i.e: they live on plants).

Cyanobacteria, of the Chamaesiphonaceae family, epiphytic on algae of the genus Cladophora, in the photos there are several stages of the reproductive cycle, x100 HI, bright field, from one brackish water aquarium, Cancún. The color is the real one the pigment this cyanophycea had.

 and the epizoics (those that live on animals).

Micro-peritrichs, fixed on the egg package of a female of a Diaptomid from Durango, Mx. fixed with GALA, mounted in PVA-G. Bright field, x100 HI.

MUTUALISM - Of these last associations of species there are some which imply that the “living support" is not only a substrate, but that shows the development of dependency relationships (denominated "mutualism") between the associate species.

Commensalism (one of the forms of mutualism) is a type of relationship in which one of the members are more or less passive, whereas the other benefits from the relation without damaging its associate. The following image, typical of a “commensal” must necessarily be large so that its structure is well appraised.

Temnocephala pignalberiae, Dioni, 1967 – Commensal on crabs from the Paraná River.  Mosaic of 6 images, bright field x4. Preparation made by Prof. Cristina Damborenea (Univ.de la Plata, Rep. Argentina). This and other Temnocephala will be described in a special article.

Symbiosis implies that both organisms benefit from each other by the intimate relation established between them. The most well known and complete example are the lichens, among the plants and termites among the animals. Lichens are classified in genus and species although in fact each “species” is an intimate and indissoluble relationship between a species of alga and another one of fungus.

Left.- hand made section of a lichen, trimmed from a picture posted to the "Forum Mikroscopia", by Advocat Andre (Aphylla) on 01/08/05. He describes an upper layer of hypha, underwhich there is a green layer of algae continued by the bluish medula and a lower grayish layer both of which are also hyphae. I have never seen such a clear illustration of the structure of a lichen. Right. - magnificent drawings, made by J. Leydi of termite symbionts. He didn't know of planachromatics, apochromatics, photomicrographic cameras, and so on. Surf the web for drawings by Joseph Leydi to see his impressive plates of protista.

A more spectacular symbiosis, with probably the older origins, although it has been accepted only recently (after 1980), is the one of all living cells with its mitochondria. According to the concepts accepted today (although sometimes still discussed) mitochondria are protobacteria (prokaryotic organisms, that is to say, without nucleus) with aerobic breathing, that introduced itself into eukaryotic cells (those with nucleus but which were anaerobic) obtaining food and protection, and offering them true power factories and the possibility of using the oxygen which by that time began to dominate the atmospheric gases.

In the following elementary references, you can see in addition to a summary of the modern theories some illustrations of the structure of mitochondria.

HTTP:they //en.wikipedia.org/wiki/Endosymbiotic_theory

Today it is unthinkable for the cellular operation of all living beings to occur without these symbionts.

There is nevertheless a habitat that the amateurs explore exceptionally and if he does, it is generally when he is already an advanced microscopist. It is no less interesting and it can be really fascinating. It is the world of the animals that choose

to live at the expense of other living species: they are the PARASITES.

Each species of plant or animal has several parasites, generally specific, which is to say that they only live on that species, and normally in a well defined niche (place and environment). Apart from my picture of gregarines below (fig 1), the presented few examples are only to suggest the enormous variety of parasitic species, and have been obtained and modified from the Internet. It must be greatly acknowledged the contribution of those who share their images, and have contributed effectively to the extension of knowledge of this form of microscopic invertebrate life.

It must be clear that numerous vegetable parasites exist; but they are mostly out of the sphere of knowledge of this author.

1- gregarines (protozoa, apicomplexa) from the intestine of a naidid, x100 HI, oblique illumination, teinted blue. 2 - Echinococcus granulosus, a cestode that parasitises dogs as an adult. 3 - an acarina parasite of domestic dogs and cats. 5 - a blood parasite, a flagellate of the genus Trypanosoma. 6 - a nematode parasite on plants. 7 - one of the well known fleas.

This is the first article in a short series that tries to introduce the microscopists with a spirit of adventure to the investigation of this specialized habitat that just as the outer world offers a great diversity, and demands a variety of techniques to be investigated.

I could have selected as a subject, a frog or toad, with the certainty to find more parasite diversity.

In them it is easy to locate trypanosomes in the blood, apicomplexa (previously called esporozoa) in the gall bladder, a variety of trematodes (Digenea) (different species according to the location) in the mouth, stomach, thin intestine and rectum, and also in the urinary bladder, and even in the lungs, where they are also located specific nematodes. If this is not enough they also have cestodes in its intestines. And have even external parasites like red acarii that adheres to their skin.

But surely, although this choice would be most beneficial, probably, and for several reasons, it is not the best one for a first experience of amateur microscopists into the investigation of those who live hidden in the inner world.

I have then chosen a bug that only very few people consider a friendly pet: the cockroach.  The added picture shows a Periplaneta americana, the most common cockroach in México taken with the Cannon Power Shot A300. Natural size.

 
The second and third parts of this series are dedicated to this interesting insect and to the even more interesting parasites that are associated with it.

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