The Life of Bacteria

The Antibacterial Activity of Honey: 1. The nature of the antibacterial activity

Soils were collected from two locations at six sites on each of eight soil types. After sieving, soil CO2 evolution was measured at three moisture contents and at 5, 10, 15 and 20°C. Our objectives were to (i) establish a regression model for the relationships between CO2 evolution, temperature and soil moisture content, and (ii) to investigate which aspects of this regression apply universally and which are specific to individual soil types. The same soil samples were used at the different temperatures, giving CO2 data which were repeated or longitudinal measurements. This experimental structure has implications for the covariance structure of the data. A preliminary analysis of the data showed that a natural logarithmic transformation of CO2 evolution rates was effective both in linearizing the mean response and in stabilizing its variance. When CO2 evolution was expressed as ln(ml CO2 kg−1 loss-on-ignition h−1) and the soil moisture content as a proportion of the water-holding capacity, the shapes of the curves of CO2 evolution against moisture content and the positions of their maxima became more similar than when CO2 evolution and soil moisture content were expressed on an oven-dry weight basis. The average responses of ln(ml CO2 kg−1 LOI h−1) of the soil types to temperature over the range 5–20°C were remarkably close to a set of parallel straight lines. This resulted in the formulation of a model in which: (a) the mean value of ln(ml CO2 kg−1 LOI h−1) at each site within a given soil type can be described by a regression which is linear on temperature and quadratic on soil moisture content; (b) the mean value of the linear coefficient of temperature is common to all the soil types studied; and (c) the mean values of the intercept, and of both the linear and quadratic coefficients of moisture, vary stochastically between soil types. A classification of soil types on the basis of their mean regression coefficients is: (i) brown calcareous earths, typical brown earths, (ii) mimic alluvial gley soils, (iii) typical brown podzolic soils, podzols, stagnohumic gley soils, stagnopodzols, (iv) raw peat soils.

Relationships between CO2 evolution, moisture content and temperature for a range of soil types

Hormesis: U-shaped dose responses and their centrality in toxicology

Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, New Zealand Introduction Honey is gaining acceptance by the medical profession for use as an antibacterial agent for the treatment of ulcers and bed sores, and other surface infections resulting from burns and wounds 4,135 . In many cases it is being used with success on infections not responding to standard antibiotic and antiseptic therapy. Its effectiveness in rapidly clearing up infection and promoting healing is not surprising in light of the large number of research findings on its antibacterial activity, covered in Part 1 of this review (Bee World 73(1): 5-28, 1992).

/pdf/the-antibacterial-activity-of-honey-2-variation-in-the-27awbu2zk5.pdf

The antibacterial activity of honey: 2. Variation in the potency of the antibacterial activity

Several categories of biological microstructures 1.9± billion years old are here described, illustrated, and referred to a group of early thallophytes that includes the thread bacteria and the blue-green algae. These microstructures were almost surely autotrophic and in the line of evolution toward green-plant photosynthesis, if not themselves oxygen producers. Geochemical evidence has been interpreted by some to imply that the contemporaneous atmosphere was essentially anoxygenic (reducing), and by others to indicate an atmosphere rich in oxygen. These conflicting interpretations may be reconciled by a hypothesis, based on demonstrable fossil organisms, that calls for local centers of biologic oxygen generation.

https://science.sciencemag.org/content/sci/148/3666/27.full.pdf

Significance of the Gunflint (Precambrian) Microflora: Photosynthetic oxygen may have had important local effects before becoming a major atmospheric gas.

The Life of Bacteria

Citations

The Antibacterial Activity of Honey: 1. The nature of the antibacterial activity

Relationships between CO2 evolution, moisture content and temperature for a range of soil types

Hormesis: U-shaped dose responses and their centrality in toxicology

The antibacterial activity of honey: 2. Variation in the potency of the antibacterial activity

Significance of the Gunflint (Precambrian) Microflora: Photosynthetic oxygen may have had important local effects before becoming a major atmospheric gas.

Related Papers (5)

The Life of Bacteria

Bacterial chemistry and physiology

Bacteria and bedscreens

GenomeComplexity ofMethanogenic Bacteria

Ammoniaproduction byintestinal bacteria