Inhibition of growth of Bradyrhizobium japonicum bacteroid by spermidine and spermine in yeast extract

Abstract

Bacteroids are defined as the symbiotic forms of Rhizobium or Bradyrhizobium cells in the root nodules of their legume host. The differentiation to bacteroids involves various physiological changes and may be associated with some genetical changes. Single-colony isolates from a nodule formed by a Bradyrhizobium strain often differed in their effectiveness and intrinsic antibiotic resistance (Weaver and Wright 1987; Ozawa unpublished data). Detailed analysis of the changes in the gene structure requires the isolation of individual bacteroids from a nodule. However it has been reported that the viability of bacteroids in culture is very low and only a small fraction of a bacteroid population could produce colonies on yeast extract-mannitol (YEM) agar (Sutton et al. 1977). Bergersen (1974) concluded that the reversion of bacteroids to the vegetative, growing form is very rare.     

Stand structure and plant species occurrence in forest edge habitat along different aged roads on Okinawa Island, southwestern Japan

We compared stand structure and plant species occurrence on the shoulders of 3-, 10- and 20-year-old roads in a subtropical evergreen broad-leaved forest to document temporal changes in edge effects of forest roads. We recorded 154 vascular species in the study plots, including 3 non-native species. We used generalized linear mixed models to analyze changes in forest structure and plant species composition in relationship to the distance from forest roads. The spatial patterns in stand structure at different distances from roads differed with road age. The large canopy openness on the edge of 3-year-old roads decreased with time after the construction. A progressive decrease in tree height on roadsides was observed after the road construction, suggesting tall trees could not withstand the dry and windy roadside environment. The edge effect on the canopy tended to be larger at higher elevation sites. The spatio-temporal pattern of species occurrence based on distance from roads differed by species. Typical pioneer species such as Schima wallichii and Eurya japonica increased along the edge, while less aggressive pioneer species and understory species decreased. As time passed after the road construction, some climax and understory species decreased at the forest edge, while other climax and understory species increased. The modeling methods proposed in this study could be applied to different roadside and edge study sites.     

Relationship between serum biochemical values and marbling scores in Japanese Black steers.

In order to obtain available biochemical parameters related to the marbling score (MS), by which the meat was graded from 1 to 12 in Japan, serum biochemical values were examined in 13 Japanese Black steers during the fattening stages. The steers were divided into high MS (8-11) and low MS (4-5) groups and the fattening stage was also divided into 4 stages according to their feed contents; Stage I (11-13 month-old; 0-4 months after the fattening (af)), II (5-9 months af), III (10-14 months af), and IV (15-20 months af). High MS group showed significantly higher levels in glucose and urea nitrogen (at Stage I), albumin/globulin ratio (at Stage II), and magnesium (at Stage I and III), and lower level in vitamin A (at Stage III) than low MS group. These biochemical parameters, indicating conditions of steers during the fattening stages, are considered to have a possibility related to MS in fattening steers.     

Behavior of monolignol glucosides in angiosperms

To examine the behavior of cinnamaldehyde and cinnamyl alcohol glucosides in lignifying tissues, angiosperms were subjected to tracer experiments using radioisotope-labeled and stable isotope-labeled glucosides. The aglycone from coniferaldehyde glucoside was efficiently incorporated into guaiacyl and syringyl lignin as a cinnamyl alcohol unit. The aglycone from coniferin was also incorporated into guaiacyl and syringyl lignin. However, some of the coniferin-derived aglycone that was incorporated into lignin passed through a cinnamaldehyde form prior to dehydrogenative polymerization. When coniferin was administered together with coniferaldehyde glucoside, syringyl units were rarely synthesized from coniferin via the cinnamyl alcohol stage, whereas numerous syringyl units were synthesized from coniferaldehyde glucoside. These observations suggest that the coniferaldehyde form is crucial for the biosynthesis of syringyl lignin in angiosperms.     

Effect of cooled and chlorinated chiller water on Campylobacter and coliform counts on broiler carcasses during chilling at a middle-size poultry processing plant

To evaluate the effect of cooled and chlorinated chill water for Campylobacter and coliforms at a middle-size processing plant which was considered to be difficult for eliminate pathogenic bacteria on carcasses, following three conditions were examined; keeping temperature at < 20, < 10 and < 10°C, and chlorine concentration at < 50, < 50 and 50 to 70 ppm during processing in experiment 1, 2 and 3 respectively. Fifteen prechill and 15 postchill carcasses were examined in each experiment. In lower temperature of experiment 2, decreasing rate (%) of coliforms was significantly higher (P<0.01) than that in experiment 1. In higher chlorination of experiment 3, no Campylobacter was detected from all postchill carcasses.     

Infectivity to hosts of the endogenous stages of chicken and murine Cryptosporidium.

Five groups of 4 mice each were inoculated with 10(6) Cryptosporidium muris oocysts. They were necropsied on days 2, 4, 6, 8 and 10. The stomach mucosa from each group were made into 10% suspension in physiological saline and were orally inoculated to 2 mice each. Recipients given suspension from infected mice on day 6, 8 and 10 shed oocysts from 6, 9 and 6, respectively. Similarly, White Leghorn received 10(6) Cryptosporidium sp. oocysts were killed daily between 1 and 6 days. Recipients given bursa of Fabricius or caecum of donor birds on days 4, 5 and 6 shed oocysts. The endogenous stages of murine and chicken Cryptosporidium were able to infect the appropriate host.