Untersuchungen zum Einfluss des D-Laktatblutspiegels auf Azidose, Körperhaltung und Verhalten bei Kälbern mit Neugeborenendurchfall

Some calves with neonatal diarrhea and distinctly disturbed general condition have elevated blood levels of D-lactate and respond poorly to the usual correction of acidosis. This observation led to this prospective study with the objective to elucidate whether calves with elevated D-lactate levels require higher doses of sodium bicarbonate and more frequent treatments than calves with normal D-lactate levels. Among the calves admitted to the clinic between September, 2002, and March, 2003, 73 calves with an age of up to 3 weeks were included in this study. Further selection criteria were diarrhea (according to the history or upon admission), and metabolic acidosis with a base excess below -10 mmol/l. Exclusion criteria were hypoglycemia, hyperkalemia, evidence of myodystrophy, severe bronchopneumonia, and navel ill requiring surgical intervention. Within the period of investigation (24 hours) the calves received a standardized therapy but no anti-inflammatory drugs and no oral rehydration solutions. Dosage of sodium bicarbonate was calculated using the formula body weight x base deficit x 0.6 and administered in a volume of 2.5 liters within 3.5 hours. During the subsequent 20 hours the calves received infusions of 0.9 % sodium chloride in volumes corresponding to the estimated fluid loss. Blood samples were taken before the infusion and after four and 24 hours and assayed for D-lactate concentration and base excess; additionally, behavior and posture of the calves were recorded. Voluntary milk intake at the first regular feeding after the end of the investigation was also recorded. Approximately 85 % of the calves had elevated D-lactate levels. Significant correlations between D-lactate levels and both behavior and posture were found, allowing for a relatively reliable diagnosis of hyper-D-lactatemia on the basis of clinical signs. Posture and behavior seemed to be more strongly influenced by D-lactate than by degree of acidosis. No correlations were found between either D-lactate level or base excess, and milk intake. Mean D-lactate concentration decreased very little after the first four hours, whereas a distinct drop was observed after the subsequent 20 hours. A possible explanation for this finding is that metabolism of D-lactate increases after the normalization of blood pH. Significant correlations between D-lactate levels and base excess after the sodium bicarbonate infusion indicate that calves with elevated D-lactate levels have received to little buffer. Furthermore significant correlations between D-lactate levels and base excess after 24 hours indicate that those calves, which still had elevated D-lactate levels after this period of time, in most cases required a repeated treatment with buffer. Conclusion: Calves with clinical evidence of D-lactate acidosis require higher doses of buffer and possibly repeated treatments

Heterozygous Variants in KMT2E Cause a Spectrum of Neurodevelopmental Disorders and Epilepsy.

We delineate a KMT2E-related neurodevelopmental disorder on the basis of 38 individuals in 36 families. This study includes 31 distinct heterozygous variants in KMT2E (28 ascertained from Matchmaker Exchange and three previously reported), and four individuals with chromosome 7q22.2-22.23 microdeletions encompassing KMT2E (one previously reported). Almost all variants occurred de novo, and most were truncating. Most affected individuals with protein-truncating variants presented with mild intellectual disability. One-quarter of individuals met criteria for autism. Additional common features include macrocephaly, hypotonia, functional gastrointestinal abnormalities, and a subtle facial gestalt. Epilepsy was present in about one-fifth of individuals with truncating variants and was responsive to treatment with anti-epileptic medications in almost all. More than 70% of the individuals were male, and expressivity was variable by sex; epilepsy was more common in females and autism more common in males. The four individuals with microdeletions encompassing KMT2E generally presented similarly to those with truncating variants, but the degree of developmental delay was greater. The group of four individuals with missense variants in KMT2E presented with the most severe developmental delays. Epilepsy was present in all individuals with missense variants, often manifesting as treatment-resistant infantile epileptic encephalopathy. Microcephaly was also common in this group. Haploinsufficiency versus gain-of-function or dominant-negative effects specific to these missense variants in KMT2E might explain this divergence in phenotype, but requires independent validation. Disruptive variants in KMT2E are an under-recognized cause of neurodevelopmental abnormalities

Competition and feeding ecology in two sympatric Xenopus species (Anura: Pipidae)

CITATION: Vogt, S., et al. 2017. Competition and feeding ecology in two sympatric Xenopus species (Anura: Pipidae). PeerJ, 5:e3130, doi:10.7717/peerj.3130/table-1.The original publication is available at https://peerj.comPublication of this article was funded by the Stellenbosch University Open Access Fund.The widespread African clawed frog (Xenopus laevis) occurs in sympatry with the IUCN Endangered Cape platanna (Xenopus gilli) throughout its entire range in the south-western Cape, South Africa. In order to investigate aspects of the interspecific competition between populations of X. laevis and X. gilli, an assessment of their niche differentiation was conducted through a comprehensive study on food composition and trophic niche structure at two study sites: the Cape of Good Hope (CoGH) and Kleinmond. A total of 399 stomach contents of X. laevis (n = 183) and X. gilli (n = 216) were obtained together with samples of available prey to determine food preferences using the Electivity index (E*), the Simpson’s index of diversity (1 − D), the Shannon index (H′), and the Pianka index (Ojk). Xenopus gilli diet was more diverse than X. laevis, particularly in Kleimond where the Shannon index was nearly double. Both species were found to consume large amounts of tadpoles belonging to different amphibian species, including congeners, with an overall higher incidence of anurophagy than previously recorded. However, X. laevis also feeds on adult X. gilli, thus representing a direct threat for the latter. While trophic niche overlap was 0.5 for the CoGH, it was almost 1 in Kleinmond, suggesting both species utilise highly congruent trophic niches. Further, subdividing the dataset into three size classes revealed overlap to be higher in small frogs in both study sites. Our study underlines the importance of actively controlling X. laevis at sites with X. gilli in order to limit competition and predation, which is vital for conservation of the south-western Cape endemic.https://peerj.com/articles/3130/Publisher's versio

Are invasive populations characterized by a broader diet than native populations?

International audienceBackground. Invasive species are among the most significant threats to biodiversity. The diet of invasive animal populations is a crucial factor that must be considered in the context of biological invasions. A broad dietary spectrum is a frequently cited characteristic of invasive species, allowing them to thrive in a wide range of environments. Therefore, empirical studies comparing diet in invasive and native populations are necessary to understand dietary requirements, dietary flexibility, and the associated impacts of invasive species.Methods. In this study, we compared the diet of populations of the African clawed frog, Xenopus laevis in its native range, with several areas where it has become invasive. Each prey category detected in stomach contents was assigned to an ecological category, allowing a comparison of the diversity of ecological traits among the prey items in the diet of native and introduced populations. The comparison of diets was also performed using evenness as a niche breadth index on all sampled populations, and electivity as a prey selection index for three out of the six sampled populations.Results. Our results showed that diet breadth could be either narrow or broad in invasive populations. According to diet and prey availability, zooplankton was strongly preferred in most cases. In lotic environments, zooplankton was replaced by benthic preys, such as ephemeropteran larvae.Discussion. The relative proportions of prey with different ecological traits, and dietary variability within and between areas of occurrence, suggest that X. laevis is a generalist predator in both native and invasive populations. Shifts in the realized trophic niche are observed, and appear related to resource availability. Xenopus laevis may strongly impact aquatic ecosystems because of its near complete aquatic lifestyle and its significant consumption of key taxa for the trophic relationships in ponds

Impacts of Climate Change on the Global Invasion Potential of the African Clawed Frog <i>Xenopus laevis</i> - Fig 2

<p>Global shift maps derived from Maxent illustrating predicted gains (dark violet) and losses (dark blue) of environmentally suitable space for different climate change scenarios; <b>A)</b> IPCC RCP2.6, <b>B)</b> IPCC RCP4.5, <b>C)</b> IPCC RCP6, <b>D)</b> IPCC RCP8.5.</p

Environmentally suitable space given as percent of the world’s surface area for current climatic conditions and projections onto climate change scenarios.

<p>Percentages refer to the SDM-MESS area; values increasing with climate change scenarios are displayed in bold.</p