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Laboratory bioassays were conducted between 2014-2016 at Wayne State University in cooperation with USGS to determine if different species of cyanobacteria influence quagga mussel spawning and fertilization success. The data describes the algal cultures tested and their density/concentration, the number of individuals tested, and the spawning and fertilization success of quagga mussels exposed to the cyanobacteria and those that were not (control).
Recent studies suggest the necessity of understanding the interactive effects of predation and productivity on species coexistence and prey diversity. Models predict that coexistence of prey species with different competitive abilities can be achieved if inferior resource competitors are less susceptible to predation and if productivity and/or predation pressure are at intermediate levels. Hence, predator effects on prey diversity are predicted to be highly context dependent: enhancing diversity from low to intermediate levels of productivity or predation and reducing diversity of prey at high levels of productivity or predation. While several studies have examined the interactive effects of herbivory and productivity on primary producer diversity, experimental studies of such effects in predator-prey systems are rare. We tested these predictions using an aquatic field mesocosm experiment in which initial density of the zooplankton predator Notonecta undulata and productivity were manipulated to test their interactive effects on diversity of seven zooplankton, cladoceran species that were common in surrounding ponds. Two productivity levels were imposed via phosphorus enrichment at levels comparable to low and intermediate levels found within neighboring natural ponds. We used open systems to allow for natural dispersal and behaviorally-mediated numerical responses by the flight-capable predator. Effects of predators on zooplankton diversity depended on productivity level. At low and high productivity, prey species richness declined while at high productivity it showed a unimodal relationship with increasing the predator density. Effects of treatments were weaker when using Pielou's evenness index or the inverse Simpson index as measures of prey diversity. Our findings are generally consistent with model predictions in which predators can facilitate prey coexistence and diversity at intermediate levels of productivity and predation intensity. Our work also shows that the functional form of the relationship between prey diversity and predation intensity can be complex and highly dependent on environmental context.
Elucidating the cold tolerance mechanism of Paeonia lactiflora, which is one of the most valuable ornamental and medicinal plants in Asia, fundamentally impacts its breeding and production. The glycerol-3-phosphate acyltransferase (GPAT) gene plays a pivotal role in cold resistance in a variety of plant species. The researchers in this study cloned the P. lactiflora GPAT gene, determined its expression pattern, and tested its role in cold resistance. They obtained the full-length P. lactiflora GPAT gene using tissue-cultured seedlings and real-time polymerase chain reaction and rapid amplification of cDNA ends analyses. They named this gene PlGPAT in P. lactiflora. Phylogenetic analysis indicates that the PlGPAT gene is closely related with the GPAT genes in core eudicots. The phylogenetic tree containing 31 angiosperm species based on GPAT protein sequences is largely consistent with the known phylogeny in flowering plants. They conducted a time-course PlGPAT expression analysis and demonstrated that PlGPAT expression is correlated with low-temperature stress. Our results suggest that the PlGPAT gene plays an important role in regulating cold resistance in P. lactiflora.
This study examines the whether there is a phylogenetic structure to such episodes of changes in encephalization across mammals. Researchers used phylogenetic techniques to analyze brain mass, body mass and encephalization quotient (EQ) among 630 extant mammalian species. All data on body mass and brain mass of mammals were collected from published literature sources, except for brain masses measured directly from post-mortem specimens the researchers' own collections, and have been entered into a MySQL database.