what does a negative result for the endospore test indicate about the organism? positive results indicate that the cell has the ability to form spores, while negative results indicate that the cell does not produce spores.

So a positive control for the Endospore stain would be a bacterium that produces endospores; a negative control would be any type of bacteria that are not endospore producers. The Endospore stain is used to identify bacteria that can produce tough, dormant spores.

Essentially, endospore stain is a differential stain. As such, it allows for the differentiation of structures and thus the characterization of a cell based on its physical and chemical nature.

If you get a positive result for the spore stain, it indicates (barring contamination)that the organismSECTION 3 Microscopy and Staining 14produces spores. A negative result for the sporestain might mean the organism cannot producespores, or CAN and just ISN’T.

When decolorized with acid alcohol color washes off the vegetative cells and makes them colorless. Since the counterstain nigrosin is negatively charged, bacterial cells don’t easily take up the counterstain. Therefore, vegetative cells appear colorless, endospores stain red, and the background is black.

positive/negative: endospores stain green and may be seen inside cells or outside cells. endospore negative cells stain red with no evidence of green staining. ex. bacillus subtilis and clostridium are examples of endospore positive bacteria.

Some suitable negative stains include ammonium molybdate, uranyl acetate, uranyl formate, phosphotungstic acid, osmium tetroxide, osmium ferricyanide and auroglucothionate. These have been chosen because they scatter electrons strongly and also adsorb to biological matter well.

Spore-forming bacteria include Bacillus (aerobic) and Clostridium (anaerobic) species. The spores of these species are dormant bodies that carry all the genetic material as is found in the vegetative form, but do not have an active metabolism.

Negative staining produces an outline or silhouette of the organisms against a colorful background (Figure 2). Because cells typically have negatively charged cell walls, the positive chromophores in basic dyes tend to stick to the cell walls, making them positive stains.

The main benefit of a gram stain is that it helps your doctor learn if you have a bacterial infection, and it determines what type of bacteria are causing it. This can help your doctor determine an effective treatment plan.

Do NOT decolorize for a full minute! The decolorizer should stay on the slide for no more than 15 seconds! If the decolorizer is left on too long, even gram positive cells will lose the crystal violet and will stain red.

Though gram-negative bacteria are harder to destroy, gram-positive bacteria can still cause problems. Many species result in disease and require specific antibiotics.

5 Types of Bacteria According to Gram Staining: Coccus – These are rounded or spherical in shape and may occur in chains or clusters. These occurs abundantly in the environment and also as a normal commensal on the human body (in nostrils, skin, oral cavity and genitals).

The Gram-positive cocci are the leading pathogens of humans. It is estimated that they produce at least a third of all the bacterial infections of humans, including strep throat, pneumonia, otitis media, meningitis, food poisoning, various skin diseases and severe types of septic shock.

Cocci Examples Cocci that are in pairs are known as diplococci (examples include, Streptococcus pneumoniae and Neisseria gonorrhoeae). Streptococci are cocci strings (e.g. Streptococcus pyogenes). Staphylococci are colonies of cocci that are irregular (grape-like) (e.g. Staphylococcus aureus).

Top Ten Bacteria

1. Wolbalchia spp. A poster-child for selfishness, and arguably the most successful parasite on the planet.
2. Desulforudis audaxviator.
3. Deinococcus radiodurans.
4. Myxococcus xanthus.
5. Yersinia pestis.
6. Escherichia coli.
7. Salmonella typhimurium.
8. Epulopiscium spp.

Types

• Spherical: Bacteria shaped like a ball are called cocci, and a single bacterium is a coccus. Examples include the streptococcus group, responsible for “strep throat.”
• Rod-shaped: These are known as bacilli (singular bacillus).
• Spiral: These are known as spirilla (singular spirillus).

Individual bacteria can assume one of three basic shapes: spherical (coccus), rodlike (bacillus), or curved (vibrio, spirillum, or spirochete).

Traits that can be valuable aids to identification are combinations of cell shape and size, gram stain reaction, acid-fast reaction, and special structures including endospores, granules, and capsules.

Most bacteria come in one of three basic shapes: coccus, rod or bacillus, and spiral.

The three basic shapes are a square, a triangle and a circle.

The arc (think: circle) is the strongest structural shape, and in nature, the sphere is the strongest 3-d shape. The reason being is that stress is distributed equally along the arc instead of concentrating at any one point. Storage silos, storage tanks, diving helmets, space helmets, gas tanks, bubbles, planets, etc.

1. natural shape – a shape created by natural forces; not man-made. shape, form – the spatial arrangement of something as distinct from its substance; “geometry is the mathematical science of shape” leaf form, leaf shape – any of the various shape that leaves of plants can assume.

Shape is the property of a two-dimensional form, usually defined by a line around it or by a change in color. There are two main types of shapes, geometric and organic.

Shapes fit easily into two basic categories: geometric and organic. are easy to recognize, such as circles, squares, and triangles.

The square, circle, and triangle are the most basic shapes on Earth, supporting structures both synthetic and natural.

In the visual arts, shape is a flat, enclosed area of an artwork created through lines, textures, colours or an area enclosed by other shapes such as triangles, circles, and squares. Likewise, a form can refer to a three-dimensional composition or object within a three-dimensional composition.