failure to properly culture microorganisms may result in experiments being
unsuccessful. Microorganisms can be divided into bacteria, yeasts, fungi, and
actinomycetes.
1. Bacteria
Quantitatively, a large number of marine bacteria are aerobic or facultative
anaerobic bacteria. They generally have low nutrient demands and belong
to the category of heterotrophic bacteria. In addition to seawater, bacteria
also inhabit sediment on the ocean floor, the inner and outer surfaces of
other marine organisms, and the carcasses or excretions of other organisms.
In the case of Gram-positive types, heterotrophic bacteria may be identified
by sugar fermentation, oxidase activity, the presence or absence of pigments in the body, movement, the presence or absence of flagella, and salt
demands. They include Aeromonas, Vibrio, Cytophaga, Flavobacterium,
Pseudomonas, Alteromonas, Chromobacterium, Caulobator, Acinetobactor, and Moraxella. Gram-negative types may be classified by shape
(bacillus and coccus) or by the presence or absence of motility, catalase
activity, sugar fermentation, and mycelium formation. They include
Clostridium, Bacillus, Lactobacillus, Streptomyces, Nocardia, Athrobactor, Corynebacterium, Staphylococcus, Micrococcus, and yeasts.
2. Actinomycetes
Marine actinomycetes remain an unexplored area. While large numbers of
coastal actinomycetes are believed to drift inland, some are thought to
produce new secondary metabolites due to their adaptations to the marine
environment.
3. Yeasts
In addition to land environments, yeasts exist in seawater, in soil on the
ocean floor, and in sediments, plankton, seaweeds, and higher plants and
animals. Most of the 180 species reported to date are distributed across
land and sea; around 20 species exist solely in marine environments.
Physiological characteristics of marine yeasts include strong salt tolerance,
a preference for low temperatures (failing to grow above 25 °C), and an
optimal pH around neutral. In terms of nutrient demands, they are capable
of growing in oligotrophic open-sea conditions.
10.2.3 Sampling of Marine Organism Specimens
Organisms inhabiting marine environments are very diverse in sampling sites,
types, and shapes, ranging from microscopic plankton to large plants and animals,
from the poles to tropical regions, and from tideland to the deep sea bottom. They
are also extremely diverse in size, quantity, and specimen properties.
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10 Marine Natural Substances
unsuccessful. Microorganisms can be divided into bacteria, yeasts, fungi, and
actinomycetes.
1. Bacteria
Quantitatively, a large number of marine bacteria are aerobic or facultative
anaerobic bacteria. They generally have low nutrient demands and belong
to the category of heterotrophic bacteria. In addition to seawater, bacteria
also inhabit sediment on the ocean floor, the inner and outer surfaces of
other marine organisms, and the carcasses or excretions of other organisms.
In the case of Gram-positive types, heterotrophic bacteria may be identified
by sugar fermentation, oxidase activity, the presence or absence of pigments in the body, movement, the presence or absence of flagella, and salt
demands. They include Aeromonas, Vibrio, Cytophaga, Flavobacterium,
Pseudomonas, Alteromonas, Chromobacterium, Caulobator, Acinetobactor, and Moraxella. Gram-negative types may be classified by shape
(bacillus and coccus) or by the presence or absence of motility, catalase
activity, sugar fermentation, and mycelium formation. They include
Clostridium, Bacillus, Lactobacillus, Streptomyces, Nocardia, Athrobactor, Corynebacterium, Staphylococcus, Micrococcus, and yeasts.
2. Actinomycetes
Marine actinomycetes remain an unexplored area. While large numbers of
coastal actinomycetes are believed to drift inland, some are thought to
produce new secondary metabolites due to their adaptations to the marine
environment.
3. Yeasts
In addition to land environments, yeasts exist in seawater, in soil on the
ocean floor, and in sediments, plankton, seaweeds, and higher plants and
animals. Most of the 180 species reported to date are distributed across
land and sea; around 20 species exist solely in marine environments.
Physiological characteristics of marine yeasts include strong salt tolerance,
a preference for low temperatures (failing to grow above 25 °C), and an
optimal pH around neutral. In terms of nutrient demands, they are capable
of growing in oligotrophic open-sea conditions.
10.2.3 Sampling of Marine Organism Specimens
Organisms inhabiting marine environments are very diverse in sampling sites,
types, and shapes, ranging from microscopic plankton to large plants and animals,
from the poles to tropical regions, and from tideland to the deep sea bottom. They
are also extremely diverse in size, quantity, and specimen properties.
352
10 Marine Natural Substances