The Shift-Work Accident Rate is More Related to the Shift Type than to Shift Rotation

The current study investigated the accident rates across morning, late, and night shifts in rotating shift-workers employed in two different shift rotations at the same steel work factory. A retrospective analysis has been performed of accident data (N = 578) over a 5-year period (2003 through 2007) of 730 male shift-workers employed in either a clockwise (mean age of the workers 38.1 ± SD 9.8 years) or counterclockwise rotation (mean age 38.0 ± SD 10.1 years) with comparable work conditions. The overall accident rate across the 24-h day was not significantly different between clockwise and counterclockwise shift rotation. In both shift-work rotations, morning shifts as opposed to night shifts exhibited a significantly higher accident rate. There was no significant difference between late shifts and morning or night shifts in either shift rotation. The increased accident rate in the morning shift at this steel factory could be related to the early starting time of the shift and to this shift being more labor intensive in both shift rotations. These findings suggest that work-related factors must be considered in addition to shift-work schedules when investigating accident rates in rotating shift-workers.     

Community evolution increases plant productivity at low diversity

Species extinctions from local communities negatively affect ecosystem functioning. Ecological mechanisms underlying these impacts are well studied, but the role of evolutionary processes is rarely assessed. Using a long‐term field experiment, we tested whether natural selection in plant communities increased biodiversity effects on productivity. We re‐assembled communities with 8‐year co‐selection history adjacent to communities with identical species composition but no history of co‐selection (‘naïve communities’). Monocultures, and in particular mixtures of two to four co‐selected species, were more productive than their corresponding naïve communities over 4 years in soils with or without co‐selected microbial communities. At the highest diversity level of eight plant species, no such differences were observed. Our findings suggest that plant community evolution can lead to rapid increases in ecosystem functioning at low diversity but may take longer at high diversity. This effect was not modified by treatments simulating co‐evolutionary processes between plants and soil organisms.     

Sequencing of multiple clostridial genomes related to biomass conversion and biofuel production

Modern methods to develop microbe-based biomass conversion processes require a system-level understanding of the microbes involved. Clostridium species have long been recognized as ideal candidates for processes involving biomass conversion and production of various biofuels and other industrial products. To expand the knowledge base for clostridial species relevant to current biofuel production efforts, we have sequenced the genomes of 20 species spanning multiple genera. The majority of species sequenced fall within the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Species were chosen based on representation in the experimental literature as model organisms, ability to degrade cellulosic biomass either by free enzymes or by cellulosomes, ability to rapidly ferment hexose and pentose sugars to ethanol, and ability to ferment synthesis gas to ethanol. The sequenced strains significantly increase the number of noncommensal/nonpathogenic clostridial species and provide a key foundation for future studies of biomass conversion, cellulosome composition, and clostridial systems biology.     

Complete genome sequence of Ignisphaera aggregans type strain (AQ1.S1)

Ignisphaera aggregans Niederberger et al. 2006 is the type and sole species of genus Ignisphaera. This archaeal species is characterized by a coccoid-shape and is strictly anaerobic, moderately acidophilic, heterotrophic hyperthermophilic and fermentative. The type strain AQ1.S1(T) was isolated from a near neutral, boiling spring in Kuirau Park, Rotorua, New Zealand. This is the first completed genome sequence of the genus Ignisphaera and the fifth genome (fourth type strain) sequence in the family Desulfurococcaceae. The 1,875,953 bp long genome with its 2,009 protein-coding and 52 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Pullulanase synthesis in Klebsiella (Aerobacter) aerogenes strains growing in continuous culture

1. Pullulanase synthesis was studied in 16 classified (N.C.I.B.) strains and in an industrial strain (R) of Klebsiella aerogenes grown in chemostats containing maltose as inducer and sole carbon source. 2. Maximum synthesis was associated with carbon-limited growth at a low dilution rate (about 0.2h(-1)). The enzyme remained firmly cell-bound and seemed to be located on the cell surface. 3. Three strains had high activity (R, N.C.I.B. 5938, 8017), twelve were intermediate, and two (N.C.I.B. 8153, 9146) had negligible activity but were inducible with pullulan. 4. Pullulan similarly induced low, but adequate, activity in the other strains in conditions (nutrient limitation other than carbon-limitation) in which pullulanase was otherwise very seriously repressed. Nevertheless, in carbon limitation pullulan induced no more enzyme than did maltose, maltotriose or oligosaccharide mixtures, and ;hyperactivity' never developed on protracted culture. 5. Cyclic AMP relieved the transient repression produced by adding glucose to maltose-limited cultures and a further change to glucose-limited conditions led to constitutive pullulanase synthesis. 6. Amylomaltase and alpha-glucosidase activities were also examined but in less detail. 7. The presence of pullulanase in maltose-limited growth is discussed, but no clear function can be assigned to it at present. The molar growth yields for all the strains were very similar, and no correlation was found between the overgrowth of one strain by another and pullulanase activity. Further, any function as a general branching enzyme in polysaccharide synthesis seems unlikely.     

Cell surface antigens on erythroid cells: A comparison of normal and anemic (WW) mice

Cell surface antigens of normal and anemic ($\text{W}\text{W}$) mouse erythroid cells have been examined in cytotoxicity assays with two rat antisera. When tested on fetal liver cells, a rat anti-erythroblast serum recognized antigen(s) present on erythroid cells early in development, while rat anti-adult red blood cell serum recognized antigen(s) present on mature erythroid cells. Each of these sera had different activity on normal (+/+ or $\text{W}\text{+}$) as compared to anemic ($\text{W}\text{W}$) erythroid cells.     

Complete genome sequence of the halophilic and highly halotolerant Chromohalobacter salexigens type strain (1H11(T))

Chromohalobacter salexigens is one of nine currently known species of the genus Chromohalobacter in the family Halomonadaceae. It is the most halotolerant of the so-called 'moderately halophilic bacteria' currently known and, due to its strong euryhaline phenotype, it is an established model organism for prokaryotic osmoadaptation. C. salexigens strain 1H11(T) and Halomonas elongata are the first and the second members of the family Halomonadaceae with a completely sequenced genome. The 3,696,649 bp long chromosome with a total of 3,319 protein-coding and 93 RNA genes was sequenced as part of the DOE Joint Genome Institute Program DOEM 2004.     

Microsatellite DNA analysis shows that greater sage grouse leks are not kin groups

The spectacular social courtship displays of lekking birds are thought to evolve via sexual selection, but this view does not easily explain the participation of many males that apparently fail to mate. One of several proposed solutions to this 'lek skew paradox' is that kin selection favours low-ranking males joining leks to increase the fitness of closely related breeders. We investigated the potential for kin selection to operate in leks of the greater sage grouse, Centrocercus urophasianus, by estimating relatedness between lekking males using microsatellite DNA markers. We also calibrated these estimates using data from known families. Mean relatedness within leks was statistically indistinguishable from zero. We also found no evidence for local clustering of kin during lek display, although males tended to range closer to kin when off the lek. These results make kin selection an unlikely solution to the lek skew paradox in sage grouse. Together with other recent studies, they also raise the question of why kin selection apparently promotes social courtship in some lekking species, but not in others.