Kill vegetation

Iodophors are complexes of iodine with a surface-active agent such as polyvinyl pyrrolidone (PVP povidone-iodine). Iodophors retain the activity of iodine. They kill vegetative bacteria, mycobacteria, fungi, and lipid-containing viruses. They may be sporicidal upon prolonged exposure. Iodophors can be used as antiseptics or disinfectants, the latter containing more iodine. The amount of free iodine is low, but it is released as the solution is diluted. An iodophor solution must be diluted according to the manufacturer s directions to obtain full activity. 

The first synthetic herbicide12 was 2,4-dichlorophenoxy-acetic acid (11.7). The one used in largest volume today is atrazine, which is typical of a group of triazine herbicides. Glyphosate (very low mammalian toxicity) is used extensively to kill vegetation nonselectively.13 Alachlor is a typ-... 

Pesticides do not always go where they are intended to go and, if they do, they do not always stay there. In aerial spraying, 50-75% of the spray can miss the target.51 If the insecticide lands on areas adjacent to the field it can harm natural insect pollinators and predators. If an herbicide lands on adjacent areas, it can kill vegetation that is the home of natural predators and pollinators. Sensitive crops in adjacent Helds can be killed. If the crop is young, most of an insecticidal spray ends up on the ground. 

Endospores can remain dormant for thousands of years. This durability and the fact that some very virulent bacteria produce endospores is the reason that they are so dangerous. They are resistant to processes that normally kill vegetative cells. 

These substances do not kill bacterial spores, mycobacterium (TB), or all viruses. Low-level disinfectants can kill vegetative bacteria, fungi, and some lipid-coated viruses such as HIV. Use low-level disinfectants such as QACs on floors, countertops, furniture, and plastic or metal housing of machines. QAC disinfectants contain their active ingredients as n-alkyl dimethyl ethylbenzyl... 

The term pasteurization is used today to apply to mild heat treatment of foods that is less drastic than sterilization. It is used to kill organisms that are relatively low in thermal resistance compared to those for which the more drastic sterilization processes are designed to eliminate. Pasteurization usually involves killing vegetative microorganisms and not heat-resistant spores. 

In case of a significant contamination, the bioreactors are cleaned and steamed at ambient pressure with the temperature reaching 80-100°C, sufficient to kill vegetative cells and fungal spores. 

DISINFECTANT A chemical agent that kills VEGETATIVE bacteria, fungi, and viruses, but not necessarily spores. 

Sulfur is assimilated by plants as the sulfate ion, S04 . In addition, in areas where the atmosphere is contaminated with SOj, sulfur may be absorbed as sulfur dioxide by plant leaves. Atmospheric sulfur dioxide levels have been high enough to kill vegetation in some areas (see Chapter 11). However, some experiments designed to show SO2 toxicity to plants have resulted in increased plant growth where there was an unexpected sulfur deficiency in the soil used for the experiment. 

Vegetation submerged from inundation of areas upstream from landslide dams also can be dated radiometrically. Similarly, landslides into lakes can submerge and kill vegetation that can be dated. 

Cells of strain 10716 cultured in environments containing less than 6 X 10 M Mn+2 are unable to synthesize detectable quantities of bacitracin (Weinberg and Tonnis, 1966). When 2 X 10" M Mn+ is supplied to such cultures during the maximum stationary phase, the peptide appears in detectable concentrations in culture supernatants within four hr. However, if a quantity of chloramphenicol sufficient to suppress protein synthesis but not to kill vegetative cells is added either simultaneously or within two hr following the addition of Mn+, bacitracin is not formed. Apparently, in cells deprived of the metalhc ion, synthesis of either amino acid racemases or peptide assembly enzymes is suppressed (Weinberg and Tonnis, 1966). 

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