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In a set of laboratory experiments, we examined competition for phosphorus between algae and bacteria under various carbon:phosphorus (C:P) supply ratios in spatially homogeneous and heterogeneous microcosms. Experimental results were compared to those predicted by theoretical models of resource competition. In the spatially heterogeneous microcosm, algae that were inferior competitors for P persisted in vessels with high local C:P supply ratios that would cause exclusion in the spatially homogeneous microcosms. Resource competition theory, adapted to this system, provided a starting point for explaining these results. Spatial structure can enhance local diversity because locally inferior competitors are transported from source habitats into sink habitats where they would otherwise be excluded. Such local sources were determined by their resource supply ratios. These results verify the hypothesis that spatial processes enhance local diversity when a system of local habitats is divided into sources and sinks in such a way that each persisting species has at least one source within the system. However, existing theoretical models did not accurately predict distributions of competitor abundance within this experimental system.

Objective To determine which chains of inter-a-inhibitorAs well as H1 and H2, the crystals from both sexes contained a protein band at #33 kDa. In many cases (IaI) are present in urine and whether they are also found in calcium oxalate (CaOx) crystals generated in there appeared to be no direct relationship between the proteins detected in the crystals and the urine human urine. Materials and methods Fresh urine specimens were colsamples from which they were derived, which probably reflects the well known instability of IaI and the lected from five women and five men with no previous history of stone disease. An aliquot of each urine was occurrence of a range of bikunin fragments in urine. Conclusion These results show for the first time that H1 retained for analysis, the remainder treated with a standard load of oxalate and the CaOx crystals precipiand H2 are present in human urine and urinary CaOx crystals, that the bikunin chain of IaI is not the only tated from each specimen demineralized with ethylenediamine tetracetic acid. The resulting organic extracts part of the molecule capable of participating in CaOx crystallization in urine, and in theory at least, in the from crystals and their corresponding urine samples were subjected to sodium dodecyl sulphate gel elecregulation of crystallization events in stone formation.

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SummaryThe plant genome is partitioned across three distinct subcellular compartments: the nucleus, mitochondria, and plastids. Successful coordination of gene expression among these organellar genomes and the nuclear genome is critical for plant function and fitness. Whole genome duplication events (WGDs) in the nucleus have played a major role in the diversification of land plants and are expected to perturb the relative copy number (stoichiometry) of nuclear, mitochondrial, and plastid genomes. Thus, elucidating the mechanisms whereby plant cells respond to the cytonuclear stoichiometric imbalance that follow WGDs represents an important yet underexplored question in understanding the evolutionary consequences of genome doubling. We used droplet digital PCR (ddPCR) to investigate the relationship between nuclear and organellar genome copy numbers in allopolyploids and their diploid progenitors in both wheat and Arabidopsis. Polyploids exhibit elevated organellar genome copy numbers per cell, largely preserving the cytonuclear stoichiometry observed in diploids despite the change in nuclear genome copy number. To investigate the timescale over which cytonuclear stoichiometry may respond to WGD, we also estimated organellar genome copy number in Arabidopsis synthetic autopolyploids and in a haploid-induced diploid line. We observed corresponding changes in organellar genome copy number in these laboratory-generated lines, indicating that at least some of the cellular response to cytonuclear stoichiometric imbalance is immediate following WGD. We conclude that increases in organellar genome copy numbers represent a common response to polyploidization, suggesting that maintenance of cytonuclear stoichiometry is an important component in establishing polyploid lineages.Significance StatementWhole genome duplications (WGD) have the potential to alter the stoichiometric balance between nuclear and organellar genomes. We used two separate diploid-polyploid complexes to show that plant cells with WGD exhibit elevated mitochondrial and plastid genome copy numbers, both immediately in lab-generated lines and in natural polyploids.