Morphology
reality, the ‘
morphology of the bacterium’ exclusively trusts confidently upon a number of factors,
namely :
the strain under investigation,
nature of the culture medium,
temperature and time of incubation,
age of the culture, and
the number of ‘subculture’ it has been subjected to.
Importantly, the various characteristic features that may be observed from such meticulous
investigational studies are : shape, size, arrangement, motility, flagella, spores, and capsules.
The
variants observed in the above cited physical characteristic features may be stated as under :
Shape :
spherical, rod shaped, comma shaped, spiral shaped, filamentous.
Axis of organism :
straight, curved.
Length and breadth :
mostly variable.
Sides of organism :
convex, concave, parallel, irregular.
Ends of organism :
tapering, rounded, straight.
Shape :
club shaped, giant forms, navicular, swollen, shadow shaped.
Arrangement
: in pairs, in tetrads, packs of eight, in chains (short or long) e.g., cocci ; in short
and long chains at random
e.g., bacilli ; in single or in ‘S’ or in spiral forms .e.g., vibrios.
Motility :
non-motile, sluggishly motile, actively motile or may show darting motility.
Forms :
atrichate (i.e., without flagella) ; monotrichate ; lophotrichate ; amphitrichate ; peritrichate ;
Spores :
oval, spherical, ellipsoidal, having same width or wider than the prevailing bacillary
body ; equatorial, subterminal or terminal.
Capsules :
may or may not be present.
Techniques used :
Electron microscopy ; phase-contrast microscopy ; background illumination ;and hanging drop preparations.