Friday, June 28, 2013

Mossy Algae under a Microscope

If you have ever walked along a river or stream you have probably noticed a mossy green alage on the rocks. If you try to step on the rocks, it is slippery.

Image: W. Bourland
This green, soft algae is referred to as cladophora. Cladophora is also known as "river weed" and in Laos it is even eaten as a delicacy in the form of dry sheets, similar to Japanese nori.

Cladophora is a filamentous bloom, meaning it is an algae with longer tendrils. It is often found on rocks in streams or rivers and growing around waterfalls. When viewed under a high power biological microscope, then longer tendrils have multiple fingers that shoot off of each branch.

Image: W. Bourland

Wednesday, June 26, 2013

Darkfield Illumination in Stereo Microscopes

Darkfield observation in stereo microscopy requires a specialized stand that contains a reflection mirror and light-shielding plate to direct a hollow cone of illumination towards the specimen at oblique angles.

The principal elements of darkfield illumination are the same for both stereo microscopes and more conventional compound (biological) microscopes, which often are equipped with complex multi-lens condenser systems.

One example of a simple add-on darkfield kit for a stereo microscope is shown below. The darkfield kit drops into the stage plate position on the MW5-L5 stereo zoom microscope.

Darkfield on a stereo microscope.
Gemologists often use darkfield for viewing diamonds and precious stones. Gemology microscopes therefore typically have a darkfield feature built into the gem stereo microscope stand.

The GEMZ-5 gemology microscope shown above has an arrow pointing to the built-in darkfield unit on the microscope.

Monday, June 24, 2013

The Kidney

Kidneys are organs that serve several essential regulatory roles in most mammals. Kidneys regulate electrolytes, they are essential to the urinary system, and they regulate blood pressure as well as filtering the blood to remove wastes.

Image courtesy Gray's Anatomy
The kidneys primary function is to filter wastes out of the body by creating urine. The kidneys also play a role in separating waste from vital nutrients and allowing the body to absorb these vital nutrients.

Kidney image courtesy Fr. Dr. Julia Enrick
The image above of a kidney was captured using a biological microscope and the Jenoptik C5 microscope camera.

Friday, June 21, 2013

Microscope Objective Abbreviation Guide

Microscope objective lenses (particularly those made for biological microscopes) often have abbreviations inscribed on them that can at times be confusing. The list below may help you decipher exactly what the inscription on your microscope objective lens stands for.
 ABBREVIATION  & Explanation:
  • ACHRO = Achromatic aberration correction
  • EF = Extended field (The field of view is less than plan)
  • PL, PLAN, PLANO = Flat field optical correction
  • N, NPL = Normal field of view plan
  • UPLAN = Universal plan (Brightfield, darkfield, polarized light)
  • LU = Luminous universal (brightfield, darkfield, DIC, polarized light)
  • PLAN APO = Apochromatic and flat field correction
  • FL, FLUOR, FLUAR = Fluorite aberration correction
  • L, LL, LD, LWD = Long working distance
  • ELWD = Extra long working distance
  • SLWD = Super long working distance
  • CORR, CR = Correction collar
  • I, IRIS = Adjustable numerical aperture with iris diaphragm
  • OIL, OEL = Oil Immersion
  • WATER, WI, WASSER = Water Immersion
  • HI = Homogeneous Immersion
  • GLY = Glycerin Immersion
  • DIC, NIC = Differential or Nomarski interference contrast
  • CF, CFI = Chrome-Free or Chrome-Free infinity corrected
  • ICS = Infinity color-corrected system
  • RMS = Royal Microscopical Society objective thread size
  • M25, M32 = Metric 25mm or 32mm objective thread
  • PHASE, PH, PC = Phase contrast
  • PH 1, 2, 3 = Phase condenser annulus 1, 2, 3
  • DL, DLL, DM, BM = For phase contrast: dark low, dark low low, dark medium, dark bright
  • PL, PLL = For phase contrast: positive low, positive low low
  • PM = For phase contrast: positive medium
  • NL, NM, NH = For phase contrast: negative low, negative medium, negative high contrast
  • P, PO, POL, SF = Strain-free, made for polarized light
  • U, UV, Universal = UV transmitting for UV-excited epifluorescence
  • M = Metallographic (no cover slip is used)
  • NC, NCG = No cover slip
  • EPI = Epi illumination
  • TL = Transmitted light
  • BBD, HD, B/D = Bright or dark field (Hell, Dunkel)
  • D, DF = Darkfield
  • H = For use with a heated stage
  • U, UT = For use with a universal stage
  • DI, MI, TI = Interferometry, Noncontact, Multiple Beam (Tolanski)

Tuesday, June 18, 2013

Kids Microscope Project: Dust

This is a simple and fun microscope project for kids of all ages.

What you need:
Kids microscope for science project.
Student Microscope

Collect the dust with your finger if it is thick enough on a window sill or in a door jam. Another great source for interesting dust to observe is from the vacuum cleaner. An intake vent for air is a great place to collect dust - look at your hair dryer or the fan vent on your computer.

If using a stereo microscope, place a small amount of dust on the glass stage. Try viewing the dust with only the light from beneath the stage, then only the light from above, and finally both lights together. What differences do you notice? Can you find any specific particles such as insect legs or carpet fibers? What about small rocks - can you tell what they are made out of?

If using a biological microscope place a small amount of dust (you may want to use an old toothbrush to do this) on the glass slide and place it beneath the microscope starting at 40x magnification. Once you have the dust particles in focus, move the slide a bit to view other particles. What do you see? Draw images of the particles you see. After you have viewed the dust a bit, you may want to place it on a depression slide with a cover slip and add a small drop of water. How do the particles change when water is added?

If you have captured some images of dust under the microscope we would love to see them posted on the Microscope World Facebook page.

Friday, June 14, 2013

Types of Microscope Plan Objective Lenses

Biological microscope objective lenses are available in several options. Each of these microscope objective lens options are described below.

Achromat Objectives - these are the most basic high power microscope objectives. Typically the outer edge of the circular image seen through the microscope will be slightly out of focus due to the curvature of the lens.

Semi-Plan Achromat Objectives - these are one step up from basic microscope objectives in that the field of view (circular image) has been corrected a bit and the outer edges will be in focus more than the standard achromat lens. However, the entire field of view will not be a completely flat and focused field - the very outer edge will still be a bit out of focus.

Plan Achromat Objectives - these microscope objectives have been corrected for lens curvature and the entire image plane is flat and in focus - including the edges of the image.

Plan Apochromat Objectives - these microscope objectives are also referred to as Plan Apo. These objectives have been corrected for four colors chromatically and spherically. Plan apochromat objective lenses are the best objectives to use for critical resolution and color photomicrography. These objectives typically have a shallower depth of field.

Plan Fluorite Objectives - these microscope objective lenses are corrected for four wavelengths, but not quite as extensively as plan apochromat objectives are. Plan fluorite objectives are well suited for photomicrography and are typically a bit less expensive than plan apochromat objectives.

If you are looking for a specific type of microscope objective lens please email Microscope World for further information.

Tuesday, June 11, 2013


Autotrophs are organisms that produce complex organic compounds (such as fat, carbohydrates or proteins) from simple substances that are found it the surroundings generally by using light from photosynthesis. These organisms make their own food by "fixing" carbon dioxide - basically they self-feed. Photoautotroph plants fix carbon using energy from the sun. Chemoautotrophs use chemical energy.

On land, most photosynthesis is performed by multicellular life (plants), but in the ocean, nearly all photosynthesis is done by single-celled organisms. The most abundant photosynthetic organism on earth is a prokaryote.

Bacteria is a prokaryote. The image below of bacteria was captured using the digital biological microscope MW4-HD2 with phase contrast.

Bacteria captured under the microscope at 1000x magnification.

You can learn more about prokaryotes in the ocean here.

Friday, June 7, 2013

Viruses In the Ocean

Viruses are the smallest and most abundant components of plankton. They range in size from 0.02 – 0.2um in diameter. In one liter of surface seawater you would find up to 10 billion viruses!

When most people think of a virus they associate it with sickness, but viruses are essential to the regulation of saltwater and freshwater ecosystems. Most marine viruses are bacteriophages, infecting the bacteria in aquatic microbial communities, and are harmless to plants and animals.

Virus particles (virions) are not alive in that they have no metabolism, no mobility with which to swim, and they do not grow. Instead, new viruses are assembled within a host cell. In order to replicate, a virus must contact an appropriate host cell and transfer its genetic material to the inside of that cell. Once inside, the viral genome directs the host cell to produce new virions. When these newly created virions exit the host cell (often killing the cell in the process), they are again lifeless particles drifting in the sea, waiting another chance encounter with the right type of cell.

Viruses are so small that they can only be viewed with a scanning electron microscope, or they can also be detected as small dots using epifluorescence microscopy with a sufficiently bright fluorescent DNA stain.

Wednesday, June 5, 2013

Where are Algae found?

In our previous post, we discussed the four characteristics that make up algae. We will now move on to the algae habitat.

Algae commonly grow in any habitat that is moist or where standing water can be found. This includes fresh water, salt water, ice, air, and even in or on other organisms or substrate. In most areas algae fare better in summer rather than winter.

Algae are often regularly found in communities, living within many other different species of plankton, algae, and zooplankton. These communities can tell a lot about the health of an ecosystem. For example, a community of Euglena (a type of Algae), Scenedesmus (genus of Algae - specifically of the Chlorophyceae) and Selenastrum likely indicates a body of water that is rich in mineral and organic nutrients.

Water may be tested for algae content by placing a sample of water on a well depression slide, covering it with a cover slip and viewing at 40x, 100x, or 400x under a biological microscope.

Image of Selenastrum courtesy of Silken Tent.
Image of Scenedesmus courtesy EPA.

Monday, June 3, 2013

What are Algae?

Algae are organisms that have evolved over time and have the following four things in common:

  1. Algae are simple organims that do not have vascular tissue. Brown algae is the only exception.
  2. The reproductive structures of algae do not have a protective layer surrounding them.
  3. Algae are photoautotrphic, which means that they produce their own food through photo synthesis (using sunlight, water and CO2). Euglena is an exception to this rule, as they ingest other organisms for food because they do not have chloroplasts.
  4. Similar to plants, algae contains chlorophyll. However, not all algae would be classified as plants.
Algae is best viewed through a high power light microscope (also known as a compound microscope or biological microscope). 

Green algae captured at 40x magnification with the BA310 microscope and a 5mp microscope camera.

Blue green algae captured at 100x magnification with the BA310 microscope and a 5mp microscope camera.