Identification Of Kentucky Land Snail Species

Land snails are members of the Phylum Mollusca and the Class Gastropoda. The importance of land snails to their native ecosystems has been greatly underestimated and understudied. For example, land snails play a huge role in the cycling of micronutrients in their ecosystems, they are active in the dispersal of plant seeds and fungal spores, and they have been shown to be bioindicators for vertebrates of conservation concern. They also contribute to the ecosystem by leaving their shells behind when they die, which is then used as a source of calcium carbonate by many species, and used in the formation of limestone. There are approximately 194 native species of snails in Kentucky, not including the 10 introduced species. The purpose of this investigation was to learn the morphology of land snail shells in order to improve identification skills. Important features used to identify land snails include the shell shape, the diameter of the shell, the reflection of the aperture lip, the umbilicus, the teeth associated with the aperture, and the number of whorls. Several local genera such as Punctum, Discus, and Haplotrema have a distinctly wide umbilicus, while genera such as Glyphyalinia, Stenotrema, and Mesodon are considered perforate to imperforate, or without an open umbilicus. The genera Triodopsis, Euchemotrema, Inflectarius, and Xolotrema all have large teeth in the aperture that can be used to identify the species based on the size and position of the teeth. This research was supported by a Morehead State University Undergraduate Research Fellowship.https://scholarworks.moreheadstate.edu/celebration_posters_2021/1005/thumbnail.jp

Fire-related cues and germination from the soil seed bank of senescent remnants of mallee vegetation on Eastern Kangaroo Island

Plant communities dominated by narrow-leaved mallee (Eucalyptus cneorifolia) are almost entirely confined to north-eastern Kangaroo Island, South Australia, an area which has been extensively cleared for agriculture. Consequently, surviving examples consist mostly of small remnants which are thought to be senescent due to the exclusion of fire. This senescence is associated with the loss of many native understory species. Prescribed burns have been suggested as a management tool to stimulate the restoration of native plants from the soil seed bank; however, no seed bank studies have previously been conducted on Kangaroo Island and the seed bank literature usually focuses on particular species rather than on plant communities. We conducted an experiment to investigate the effects of the fire-related cues heat and smoke on the germination of plants from the seed bank in soil sampled from 10 long-ungrazed narrow-leaved mallee sites on Kangaroo Island. Eighty trays of soil were monitored in a controlled glasshouse for five months after being subjected to heat and/or smoke treatments. The overall number of native, but not exotic, plant species germinating from the soil seed bank was significantly increased by all three fire-related treatments (heat, smoke and heat plus smoke) compared with the control (no fire-related treatment). Different plant life forms exhibited varying responses to heat and smoke treatments. The results of this study illustrate that the application of fire-related treatments to soil seed banks in controlled glasshouse conditions can stimulate the recruitment of native species, including several species of conservation concern. These findings also indicate the potential of using these treatments for the ex situ germination of fire dependent species for revegetation purposes and indicate aspects of prescribed burns that may be important for restoring different components of native vegetation

Chemical Reaction Networks in a Laplacian Framework

The study of the dynamics of chemical reactions, and in particular unusual phenomena such as oscillation has led to the development of mathematical strategies for understanding the equations governing their behavior. One feature of this development is the recognition that dynamical properties of a chemical reaction can be predicted from graph theoretical properties of a certain network, called a Chemical Reaction Network or CRN. It is a remarkable fact that much of the dynamics of these complicated systems of polynomial differential equations can, to a large extent, be understood by looking at an associated linear operator determined by an underlying chemical reaction network. In this paper, we use this perspective to drastically simplify the traditional treatment of the standard results pertaining to so-called deficiency zero systems of CRN theory. This also allows us to present novel proofs entirely in the more natural context of directed graph Laplacians, with minimal chemistry-specific language. In this way we provide an even more accessible introduction to the deficiency zero theory for the average mathematics student with little or no knowledge of chemistry.Comment: 21 pages, 3 figure

TCF4 deletions in Pitt-Hopkins Syndrome.

International audiencePitt-Hopkins syndrome (PHS) is a probably underdiagnosed, syndromic mental retardation disorder, marked by hyperventilation episodes and characteristic dysmorphism (large beaked nose, wide mouth, fleshy lips, and clubbed fingertips). PHS was shown to be caused by de novo heterozygous mutations of the TCF4 gene, located in 18q21. We selected for this study 30 unrelated patients whose phenotype overlapped PHS but which had been initially addressed for Angelman, Mowat-Wilson, or Rett syndromes. In 10 patients we identified nine novel mutations (four large cryptic deletions, including one in mosaic, and five small deletions), and a recurrent one. So far, a total of 20 different TCF4 gene mutations have been reported, most of which either consist in deletion of significant portions of the TCF4 coding sequence, or generate premature stop codons. No obvious departure was observed between the patients harboring point mutations and large deletions at the 18q21 locus, further supporting TCF4 haploinsufficiency as the molecular mechanism underling PHS. In this report, we also further specify the phenotypic spectrum of PHS, enlarged to behavior, with aim to increase the rate and specificity of PHS diagnosis