Vorticella Sighting October 29, 2008

Although the Cyclops was missing in this observation, several Vorticella were identified using 40x magnification and the reference book The Ciliated Protozoa (John D. Carliss, 1979 London,Pergamon Press 2nd edition page 273). At first observation, there were at least 6 of these, mostly around the center of the tank, seemingly attached by stalks to the Utricaria plant. Several were apparently light green, others with no discernable color. The outer "lip" is covered in cilia, giving the appearance of a spinning outer "gear" which is apparently used for motility as well as feeding. When shaken or disturbed, these organisms contract into a smaller, spherical shape and do not move again for several seconds. Using resources cited below, it was surmised that these are adult Vorticellae, that the stalk is called a Spasmoneme, and that they are free-swimming until adulthood when they have found an appropriate food source and something to use as an anchor.
"VORTICELLA
Genome Structure
Like some other ciliates, Vorticella has a deviant genetic code. UAA, a traditional stop codon, instead translates for glutamate.
The small subunit rRNA (SSrRNA) gene has proved crucial for distinguishing between Vorticella species. Because different species are physically very similar, it is difficult to tell them apart by morphological characteristics alone. SSrRNA has proved a much more effective method of classification and identification.
Cell Structure and Metabolism
Vorticella are sessile organisms. However, young Vorticella are free-swimming. Adult forms attach to substrates with contractile stalks. This stalk is a filamentous organelle called the spasmoneme. Adults can also be free-swimming if these stalks are cut. They can also detach themselves if food supplies are scarce and they need to find a new location. The spasmoneme has three cellular membranes, an extracellular matrix, and an outer sheath. These stalks coil upon contraction. It is believed that the contraction is a defense mechanism to protect Vorticella from environmental hazards such as turbulent water. Contractions also help Vorticella capture food.
Vorticella are referred to as Peritrichs, meaning that their cilia are concentrated around the mouth end of the organism, but nowhere else on the body. In the event that Vorticella becomes motile, temporary cilia will form around the body. However, once the organism has anchored itself, these cilia will disappear.
Vorticella are heterotrophic organisms. They prey on bacteria. Vorticella use their cilia to create a current of water (vortex) to direct food towards its mouth.
Typically, Vorticella reproduce via binary fission. The new organism splits from the parent and swims until it can find something on which to anchor itself. They are also capable of sexual reproduction. "
From:http://microbewiki.kenyon.edu/index.php/Vorticella


Also in evidence were a multitude of small, very fast Paramecia as well as brownish, fairly stable diatoms.

Calculating measurements under microscope

Calculating measurements under a microscope
You have an object under the microscope. The field of view is a circle of light. Using a low power objective, place a steel rule under the microscope. Let's say the field is 2.5mm, or 2500 microns under a 4x objective. Using a 40x objective, therefore reduces the field by 10, so it is now 250 microns
The object is smaller than that. You have already roughly measured the field and for that lens on your microscope You already know the object's length is smaller than 250µm. If your calculation gives something bigger than that, there is an error. Next, to calculate the object's length, first identify what you mean by the length. Once you have identified the length, figure out what portion of the field it covers. It may help you to imagine dividing the field into half, then dividing a half into two quarters, then dividing a quarter into two eighths, until you get to the size of the organism. That fraction times the field is the approximate length of the organism. Here, the organism's length is about 1/4 of a field, or 0.25 X 250µm = 62.5µm. To get the width: either do all of that again for the width, or eyeball the animal and estimate the width as a fraction of the length. For our organism we might say width = about 1/3 of length.
Fungi » Calculating measurements under a microscope Copyright © 2002–2008 by Blueswami.com. All rights reserved.

Feeding Time October 24, 2008

Feeding Time October 24, 2008
On Thursday October 24, 2008 one pellet of "Atison's Betta Food" was added to each Micro Aquaria. It is made by Ocean Nutrition, Aqua Pet Americas, 3528 West 500 South, Salt Lake City, UT 84104. Ingredients: Fish meal, wheat flower, soy meal, krill meal, minerals, vitamins and preservatives. Analysis: Crude Protein 36%; Crude fat 4.5%; Crude Fiber 3.5%; Moisture 8% and Ash 15%

Male Adult Copepod (Cyclops)

From http://fmel.ifas.ufl.edu/COPEPODS.HTM

This is the twitchy moving clear critter seen on Oct 22.

Macrocyclops as Biological Mosquito Control

From: http://fmel.ifas.ufl.edu/COPEPODS.HTM

Larval Control with Copepods
Biological control is an attractive alternative to chemical .
Macrocyclopspesticides for the supression of mosquito pests and disease vectors (Lounibos and Frank 1994) Copepods for biological control have not yet been field tested in south Florida. We are maintaining cultures of several copepod species at FMEL and are conducting experimental trials with Macrocyclops albidus, one of the more promising predatory species.

Copepod predation (AVI)
We are testing the cyclopoid copepod Macrocyclops albidus (Jurine) for biological control of mosquitoes in laboratory microcosms, in controlled field conditions, and in a long-term field experiment using discarded tires. Preliminary results indicate that this predator is highly efficient in controlling mosquitoes in all three settings, reaching close to 90% reduction in larval survival under field conditions and exceeding the recommended predation rates for

Visiting Scientist from the PedroKouri Institute of Tropical Medicineprepares larvae for experiment.effective mosquito control in laboratory experiments. The predator is most effective on 1-4 day old larvae. Alternate food and habitat structure significantly influenced the predation rates on mosquito larvae.

Introducing copepodsand mosquito larvae intothe experimental tires.Once established, the copepod has been able to maintain long-term reproducing populations in the field. This copepod species is a promising candidate for control of mosquito larvae because it is a widespread and highly effective predator that is capable of establishing and maintaining populations under a wide variety of field conditions. Additionally, M. albidus is relatively easy to culture, maintain, and deliver to the target areas.
Summary

Mosquito larvae survival in the Roundhouse experiments. M. albidus is an effective predator of mosquito larvae in artificial containers and capable of drastically reducing larval populations. Marten, considers that other species, such as Mesocyclops longisetus and Mesocyclops aspericornis may be better suited for biological control in tropical areas because they maintain larger population sizes than M. albidus (Marten 1990b and pers. comm.). However, in this study, population sizes of M. albidus in field tires were much higher than previously reported from more temperate (Marten 1990b) and tropical (Marten et al. 1994) areas. Also, because of its cold-hardiness M. albidus should be better able to maintain year-round populations in subtropical areas than species recommended for the tropics, and may be able to survive even under extreme conditions (e.g. record cold weather) which in the sub-tropics are usually of short duration For example, Schreiber et al. (1996) reported sharp declines in the populations of Mesocyclops longisetus in field tires when water temperatures dropped below 5 C, but, as previously stated, M. albidus is known to survive for months at 0 C. This species demonstrated kill rates that are more than appropriate for mosquito control and is able to survive on alternate prey when larval mosquito populations are low. In the practical sense, this species is also a good candidate for use as a mosquito control agent. The species has a worldwide distribution so seed stocks should be easy to obtain, and practical and legal problems associated with exotic species introductions would not apply. Large numbers of copepods can be produced in a small space as they can be grown in small plastic pools, plastic garbage cans, and similar inexpensive containers; and cultures do not require heavy maintenance and are relatively inexpensive to maintain. Large numbers of copepods can be kept in water in a refrigerator for months, they can survive in soil and detritus that is only slightly damp (Marten 1989), and they are not killed by many pesticides commonly used for mosquito control (Marten 1989, Tietze et al. 1994). The lag (if any) between introduction of predator populations and effective mosquito control can be eliminated by initial treatment with larvicides or Bti (Tietze et al. 1994) or simultaneous introduction of other predators such as Toxorhynchites spp. (Schreiber et al. 1996). Another attractive strategy to eliminate the lag is to introduce the copepods in early spring, when mosquito populations have not built up yet and mosquito control personnel are not as busy as during the "heavy" part of the mosquito season. Work still needs to be done on effective strategies for large-scale deployment of the copepods. However, standard spray equipment can be easily modified and calibrated to dispense intact copepods (Marten 1989), and the fact that they can withstand almost-dry conditions means that storage and transport can be accomplished without having to also store and transport large quantities of water.

Pond Life Identification Page 10/26/08

http://extension.usu.edu/aitc/teachers/pdf/microorg/activities/pondlife.pdf

Excellent chart of basic pond life

Observation 10/22/08

Notable Changes this week:

Water had evaporated substantially, leaving about ony 25-30% of original moisture. Added fresh water from lab source (distilled?) as a refill. Noted several green organisms not noticed before. One is a Desmid, about 12 of these near center of tank, slowly moving, more like floating. These are identified under 40x microscoope, look like European cucumbers, and are apparently single celled because of the single nucleus at the restrictum. Also noted 3 or 4 Pleurotonea, also green, stick-shaped, also single cell with a distinct dividing line in the center.

Also, one prevously unnoticed animal, possible the Cyclops from last week in another life phase. Also, what were previouslt thought to be paramecia are more likely Spirostome, pictured and described below. Information from: http://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/pond/index.html

The genus Spirostomum contains some of the largest Ciliates. The species pictured on this page, Spirostomum ambiguum, can grow to to a size of more than 4 millimetres. It can therefore be seen without the help of a microscope. When observed swimming in a little jar of pond water it looks like a little worm. Only with the help of a microscope you can see that it is a ciliate. The cell of this unicellular is totally covered with hairlike 'cilia'. On the picture you can see the rows of cilia running like a spiral along the body.
One of the remarkable things of Spirostomum is the way it can contract. The organism can contract it's body to 1/4 of it's length in 6-8 millisec which is the fastest contraction known in any living cell. When observing the creature under the microscope it is easy to watch the contraction by gently touching the sample.

Like many large single celled organisms (giant amoebas, or Stentor: the trumpet animalcule) it has not one nucleus but many. The nucleii form a long strand, like a string of pearls, visible as the lighter structure in the right image.
Spirostomum, like many cilates, feeds on bacteria. They are swept into the mouth opening with a row of specialized fused cilia. The mouth opening is very small and can be found on the side of the body.

These critters move in a spiral, slow fashion.

A variety of Desmids are shown below. The cucumber shaped one ant the more stick-shaped Pleurotoneum are in the study tank. Photo from
DESMIDS
by Wim van Egmond

http://www.microscopy-uk.org.uk/index.html?http://www.microscopy-uk.org.uk/pond/index.html