Positive and negative impacts of plants on acid production in exposed acid sulphate soils

This study examined the impact of plants on acid sulphate soils with the aim of determining whether plants are able to reduce acid production. The study was conducted with clayey acid sulphate soil under controlled conditions with treatments lasting up to 24 weeks and measurements made in the top 0?C60 mm of soil. pH profiles in the soil were strongly dependent on soil moisture and the pattern of irrigation. When bare soil was allowed to dry down without further irrigation, there was very little acidification of either the surface or subsurface layers. Planting of Phragmites accelerated soil drying and caused extensive cracking and acidification of the subsoil under simulated drought conditions. Under a wetting and drying regime, both Phragmites and a surface spreading grass Paspalum increased soil acidification, while a surface spreading herbaceous shrub Cotula had little effect on acidification. There was no evidence that live plants could ameliorate acid sulphate soils. However, application of dead plant matter to the surface of the soil was effective in reducing acidification, especially if submerged.     

Cyclic nucleotide levels in regenerating liver

Cyclic AMP and cyclic GMP levels were measured in rat liver at various times following partial hepatectomy. Cyclic AMP levels show an initial rapid dropfollowed by a biphasic increase while cyclic GMP remains at an almost constant level throughout the time period examined.     

Resource Holding Potential and the Outcome of Aggressive Interactions between Paired Male <Emphasis Type="Italic">Aegus chelifer chelifer</Emphasis> (Coleoptera: Lucanidae) Stag Beetles

Interactions between male stag beetles usually involve aggressive behavior using their long mandibles as weapons to compete with rival males over females. Considerable variation exists within populations in male body size, and may affect their behavior and the outcome of male-male contests. We investigated the aggressive interactions between male Aegus chelifer chelifer, a small tropical stag beetle species. Morphological traits in relation to aggressiveness and the outcome of fights were examined in laboratory-reared beetles. The fight-engagement ratios of major and minor morph males were not significantly different and analyses revealed that the size of body parts had more effect on the fighting success than the weapon part (mandibles). The probability of winning a contest was higher in males with a larger head width (HW), and so HW was considered as the resource holding potential (RHP). No effects of the trait size on the initiation of fights or aggressive intensity was found. Relationships between the fight duration and RHP were not significantly consistent with any assessment strategies, but were close to the mutual assessment model.     

Recruitment of TBK1 to cytosol‐invading Salmonella induces WIPI2‐dependent antibacterial autophagy

Mammalian cells deploy autophagy to defend their cytosol against bacterial invaders. Anti‐bacterial autophagy relies on the core autophagy machinery, cargo receptors, and “eat‐me” signals such as galectin‐8 and ubiquitin that label bacteria as autophagy cargo. Anti‐bacterial autophagy also requires the kinase TBK1, whose role in autophagy has remained enigmatic. Here we show that recruitment of WIPI2, itself essential for anti‐bacterial autophagy, is dependent on the localization of catalytically active TBK1 to the vicinity of cytosolic bacteria. Experimental manipulation of TBK1 recruitment revealed that engagement of TBK1 with any of a variety of Salmonella‐associated “eat‐me” signals, including host‐derived glycans and K48‐ and K63‐linked ubiquitin chains, suffices to restrict bacterial proliferation. Promiscuity in recruiting TBK1 via independent signals may buffer TBK1 functionality from potential bacterial antagonism and thus be of evolutionary advantage to the host.     

Insights into virus evolution and membrane biogenesis from the structure of the marine lipid-containing bacteriophage PM2

Recent, primarily structural observations indicate that related viruses, harboring no sequence similarity, infect hosts of different domains of life. One such clade of viruses, defined by common capsid architecture and coat protein fold, is the so-called PRD1-adenovirus lineage. Here we report the structure of the marine lipid-containing bacteriophage PM2 determined by crystallographic analyses of the entire approximately 45 MDa virion and of the outer coat proteins P1 and P2, revealing PM2 to be a primeval member of the PRD1-adenovirus lineage with an icosahedral shell and canonical double beta barrel major coat protein. The view of the lipid bilayer, richly decorated with membrane proteins, constitutes a rare visualization of an in vivo membrane. The viral membrane proteins P3 and P6 are organized into a lattice, suggesting a possible assembly pathway to produce the mature virus.     

Microarray analysis of defined Mycobacterium tuberculosis populations using RNA amplification strategies

Background

Halibuts are commercially important flatfish species confined to the North Pacific and North Atlantic Oceans. We have determined the complete mitochondrial genome sequences of four specimens each of Atlantic halibut (Hippoglossus hippoglossus), Pacific halibut (Hippoglossus stenolepis) and Greenland halibut (Reinhardtius hippoglossoides), and assessed the nucleotide variability within and between species.

Results

About 100 variable positions were identified within the four specimens in each halibut species, with the control regions as the most variable parts of the genomes (10 times that of the mitochondrial ribosomal DNA). Due to tandem repeat arrays, the control regions have unusually large sizes compared to most vertebrate mtDNAs. The arrays are highly heteroplasmic in size and consist mainly of different variants of a 61-bp motif. Halibut mitochondrial genomes lacking arrays were also detected.

Conclusion

The complexity, distribution, and biological role of the heteroplasmic tandem repeat arrays in halibut mitochondrial control regions are discussed. We conclude that the most plausible explanation for array maintenance includes both the slipped-strand mispairing and DNA recombination mechanisms.