A plasmid involved in chloramphenicol production in Streptomyces venezuelae: evidence from genetic mapping.

To test the hypothesis that chloramphenicol production in Streptomyces venezuelae depends on the presence of a plasmid, mapping analysis was carried out by using eight markers in addition to chloramphenicol production and melanoid pigment formation. The sequence of the eight markers was determined on a circular linkage map as follows: -his-ade-str-leu-lys-met-ilv-pro-(his-). This sequence resulted in the frequency of quadruple crossover (q.c.o.) recombinants having the lowest value, 3-2 to 4-9%. However, the character of chloramphenicol non-production, which was obtained by incubating mycelia with acriflavin, was not required to explain the results. From these results and other tests, it is concluded that chloramphenicol production is controlled by a plasmid. This plasmid appeared to be non-transferable in conjugation.     

Methods for the determination of deoxyribonucleic Acid homologies in streptomyces

Variations of the membrane filter technique for deoxyribonucleic acid (DNA) hybridizations were studied with respect to Streptomyces species. At the temperatures required for specific hybridization of DNA with the high melting temperature (T_m) characteristic of Streptomyces, large amounts (up to 97%) of filter-bound DNA became eluted, in all reaction mixtures studied, within 21 hr. In most solutions this leaching was increased by the presence of sheared denatured DNA. Incubation of DNA-loaded filters in a solution of 50% formamide containing 6× standard saline citrate, at 48 C for 40 hr, was judged to be the best set of conditions tested based on relatively good retention of immobilized DNA, very low hybridization with unrelated DNA of a similarly high T_m (from Sarcina lutea), and the formation of complexes similar in thermal stability to the native DNA. The expression of results as sheared DNA bound in relation to long-chain DNA retained is recommended when a high concentration of sheared DNA relative to immobilized DNA is used.     

Factors Affecting Infection of Protoplasts with Deoxyribonucleic Acid of Actinophage PK-66

To establish a method for transmission of genetic materials in the genus Streptomyces, the conditions of infection of protoplasts of S. kanamyceticus by actinophage PK-66 deoxyribonucleic acid (DNA) were studied. The protoplasts of Streptomyces were prepared by treatments with lysozyme and trypsin. The infectivity of the phage DNA was enhanced by the presence of NaCl in the medium. The optimal concentration of the protoplasts for infection with DNA was 7 x 10(7) to 4 x 10(8)/ml. A proportional relationship was found between the infectivity and the DNA concentration within a certain range. The maximal production of mature phage was achieved after 19 hr of incubation. The number of phage propagated in the infection mixture reached 10(4) plaque-forming units per ml under the appropriate conditions. The phage DNA infected not only protoplasts prepared from S. kanamyceticus but also those prepared from S. violaceoniger and S. acidomyceticus, which were resistant to intact phage PK-66.     

Land use/cover change and its drivers: a case in the watershed of Lake Kasumigaura, Japan

Land use/land cover (LULC) changes in the watershed (2,157 km²) of Lake Kasumigaura during 1979–1996 (Period-1: 1979–1990, Period-2: 1990–1996) were analyzed, and their socio-economic and biophysical drivers were compared using time-series, high-quality GIS datasets in order to examine the characteristics of a model forecasting the future LULC. The changes occurred over an area of more than 90 km² during the overall period at changing rates of 0.22% year⁻¹ in Period-1 and 0.25% year⁻¹ in Period-2. Forestland decreased most in both periods at changing rates of 0.45% year⁻¹ in Period-1 and 0.61% year⁻¹ in Period-2. However, predominant changing patterns differed, i.e., from forest to golf course in Period-1 and from forest to artificial field in Period-2. Particularly in Period-2, a significant LULC change was observed in an area of high population increase on the edge of an already high-population area. Relationships examined among LULC change, population, and rate of population change suggested that the urbanized area was highly resistant to LULC change, and that such change was less frequent in areas of population decline. Statistical analyses indicated that the most influential drivers for total LULC changes were population in Period-1 and distance from the Tokyo Station in Period-2. Since the change potentials differed between the periods, we could not assume a stationary process for the corresponding drivers. Somewhat low S values (indices for demonstrability) show that LULC changes in the watershed of Lake Kasumigaura occurred rather randomly, probably resulting in fragmentation of the landscape.     

A new genus Squamophis of Asteroschematidae (Echinodermata, Ophiuroidea, Euryalida) from Australia

Squamophis, a new genus of brittle star is described. Two species are included in the genus: Squamophis amamiensis (Okanishi & Fujita, 2009) from south-western Japan and Squamophis albozosteressp. n. from north-western Australia. Squamophisgen. n. is distinguished from the other genera of the family Asteroschematidae by the following characters: each radial shield is single-layered and is completely covered by plate-shaped epidermal ossicles, and the relative length of the longest arm spine throughout the arms is as long as the length of the corresponding arm segment. Squamophis albozosteressp. n. is distinguished from Squamophis amamiensis in having white, slightly domed, plate-shaped epidermal ossicles on the aboral side of the body, the ossicles on aboral and lateral portion of the arms form transverse rows, and the other part of aboral side of disc and basal to middle portion of arms are brown but tip of the arms are light purple.     

A taxonomic review of the genus Astrocharis Koehler (Echinodermata: Ophiuroidea: Asteroschematidae), with a description of a new species

A revision of the genus Astrocharis Koehler (Echinodermata: Ophiuroidea: Asteroschematidae) is based on 41 specimens, including three syntypes of Astrocharis virgo Koehler, one syntype of Astrocharis ijimai Matsumoto and the holotype of Astrocharis gracilis Mortensen. Astrocharis gracilis is a junior subjective synonym of A. ijimai. A. virgo and A. ijimai are redescribed. A new species, Astrocharis monospinosa is described from southwestern Japan. A tabular key to the three species of the genus Astrocharis is provided.     

Proteome-wide identification of lysine propionylation in thermophilic and mesophilic bacteria: Geobacillus kaustophilus,Thermus thermophilus,Escherichia coli,Bacillus subtilis,and Rhodothermus marinus

Extremophiles - Recent studies have revealed the physiological significance of post-translational lysine acylations such as acetylation in the regulation of various cellular processes. Here, we...