An improved method for the semicontinuous culture of bacterial populations of Nuclepore membrane filters

The present paper describes an improved method for the semicontinuous culture of bacterial populations on Nuclepore membrane filters. The filters, placed on swimming rings, are incubated in direct contact with the water surface of the flow system, and examined by fluorescence microscopy. The growth activity of both, pure cultures and natural bacterial populations, measured in the flow system is compared to the activity measured in a conventional culture system (incubation of membrane filters on the surface of paper disc saturated with incubation medium). The flow system increases the number and the spectrum of colony forming cells. The reasons for the superiority of the flow system are discussed

Enzymatic decomposition of proteins and carbohydrates in marine sediments : methodology and field observations during spring

Microbial biomass, concentrations and enzymatic decomposition rates of proteins and carbohydrates were analysed during spring 1980 from a 10 m sediment station in the Kiel Bight. During March, a considerable increase in total organic matter, proteins and carbohydrates was observed, followed by a decrease during April. The accumulation of organic matter in the sediment could be traced back to the breakdown of the algal spring bloom. Activity rates of (α-amylase, ß-D-glucosidase and proteolytic enzymes paralleled the variation pattern in concentrations of carbohydrates and proteins. During the decomposition processes, a drastic shift in the protein to carbohydrate ratio was observed. The dominating part of the enzymes involved in the decomposition of organic material obviously arose from autolysis of the algae cells themselves. After an initial depression, microbial biomass increased, obviously due to the availability of suitable substrates for microbial growth following the decomposition processes

A new method for fluorescence staining of bacterial populations on membrane filters

This article describes and discusses a new method for the fluorescence microscopic examination of bacteria on Nuclepore membrane filters. The bacteria, which have been concentrated by filtration, are stained with a solution of acridine orange. Then the filters are destained with isopropyl alkohol and xylene. This method makes it possible to recognize small bacteria and to distinguish them from detritus. Dieser Beitrag beschreibt und diskutiert eine neue Methode zur fluoreszenzmikroskopischen Untersuchung von Bakterien auf Nuclepore-Membranfiltern. Die durch Filtration angereicherten Keime werden mit einer Akridinorange-Lösung gefärbt. AnschlieBend werden die Filter mit Isopropanol und Xylol entfärbt. Diese Methode ermöglicht es, auch kleine Bakterien zu erkennen und sie von Detritus zu unterscheiden

Bakteriologische Untersuchungen im Auftriebsgebiet vor der westafrikanischen Küste und im Sediment des Küstenschelfes

With the increasing aging of an upwelling body of water, a pronounced rise in the saprophyte counts was found at first in the surface water and later also in the deeper zones. They increased, for example, at a depth of 15 meters, from 30-50 to 250 bacteria/ml, which represents a production of 4 X 10-3 mg bacterial C/m3 water. Different bacteria populations were included on the medium used for isolation, which was prepared with both sea-water and fresh water. On the former, which had relatively few species represented, the spectrum ranged from whitish to yellowish-white halophilic marine bacteria. On the tap water medium, however, dominated a spectrum of white or vividly pigmented bacteria, comprising many species, with maximal development in fresh water. It is supposed that bacteria of terrestrial origin are involved here, which are possibly carried to the sea by sand or dust storms. With regard to the colony forms, no difference between the bacteria populations within or without the upwelling water could be determined. The greatest bacterial infiltration of the sediment was found on the surface (between 16 X 103 and 80 X 103 bacteria/cm3). Already in the upper 2 cm, a strong reduction of the saprophyte count was determined, together with a relative increase of those bacteria which possess a greater range of ecological amplitude. The saprophyte counts on the sediment surface decreased with an increase of water depth. On 21 strains of bacteria isolated from the open waters, investigations were carried out on their morphological characteristics and the most important metabolic reactions