Terrestrial microorganisms

The held of marine natural products chemistry, which encompasses the study of the chemical structures and biological activities of secondary metabolites produced by marine plants, animals, and microorganisms, began in earnest in the early 1960s. " This is in stark contrast to the study of terrestrial plant natural... 

The underlying assumption driving marine natural products chemistry research is that secondary metabolites produced by marine plants, animals, and microorganisms will be substantially different from those found in traditional terrestrial sources simply because marine life forms are very different from terrestrial life forms and the habitats which they occupy present very different physiological and ecological challenges. The expectation is that marine organisms will utilize completely unique biosynthetic pathways or exploit unique variations on well established pathways. The marine natural products chemistry research conducted to date has provided many examples that support these expectations. 

Endosulfan is released to the environment mainly as the result of its use as an insecticide. Significant contamination is limited to areas where endosulfan is manufactured, formulated, applied, or disposed of. The compound partitions to the atmosphere and to soils and sediments. Endosulfan can be transported over long distances in the atmosphere, but the compound is relatively immobile in soils. It is transformed by hydrolysis to the diol and by microorganisms to a number of different metabolites. It is bioconcentrated only to low levels and does not biomagnify in terrestrial or aquatic food chains. 

Extensive studies on the effect of substrate concentration and on the bioavailability of the substrate to the appropriate microorganisms have employed samples of natural lake water supplemented with suitable nutrients. There are few additional details that need to be added since the experimental methods are straightforward and present no particular difficulties. Considerable use has also been made of a comparable methodology to determine the fate of agrochemicals in the terrestrial environment. 

Figure 2 Terrestrial plant and soil microorganism secondary metabolites currently used as drugs...

Soil is the central organizer of the terrestrial ecosystem. Soil constituents, be they minerals, organic matter, or microorganisms, are of prime importance in governing interactive physical, chemical, and biological processes in soil environments. 

Dec J, Bollag J-M, Huang PM, Senesi N (2002) Impact of interactions between microorganisms and soil colloids on transformation of organic pollutants. In Huang PM, Bollag J-M, Senesi N (eds) Interactions between soil particles and microorganisms. Impact on Terrestrial Ecosystem, vol 8, IUPAC Series of Analytical and Physical Chemistry of Environmental Systems, Wiley, Chichester, UK, pp 323-378... 

Data on nickel toxicity to terrestrial invertebrates are scarce. A soil concentration of 757 mg/kg DW soil is lethal to 50% of earthworms (Eisenia foetida) in 14 days, and higher concentrations of 1200 to 12,000 mg/kg DW soil for shorter periods produced reduced growth and survival in the same species (WHO 1991). Earthworms are less sensitive to nickel if the medium is rich in microorganisms and organic matter, thus, making the nickel less bioavailable (WHO 1991). 

Here we will describe the methods that are used to derive critical limits for soil, based on direct ecotoxicological effects on microorganisms and plants. The indirect approaches (food web models) to derive critical limits for soil based on critical limits for terrestrial fauna such as MPC values for target organisms will be also considered. 

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