Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment

Biodiversity is rapidly declining, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades.

Promoting Amphibian Conservation through the College Classroom: Detection of Batrachochytrium dendrobatidis among Local Amphibians

Many global amphibian declines have been linked to the fungal pathogen Batrachochytrium dendrobatidis (Bd). The knowledge on Bd distribution provides a fundamental basis for amphibian conservation planning. Yet, such Bd distribution information is currently insufficient, in particular at a regional scale. The college classroom provides an excellent opportunity to expand the knowledge of Bd distribution. Here we provide an example of such research projects to detect Bd prevalence among local amphibians in a college course setting and present the results of work conducted in central Pennsylvania, USA. We collected toe clips and conducted PCR assays of six species, Plethodon cinereus, Desmognathus fuscus, Notophthalmus viridescens, Lithobates catesbeianus, L. clamitans, and L. sylvaticus (59 individuals). Four groups of students independently conducted entire projects, orally presented their findings, and submitted manuscripts to the professor at the end of the semester. This example demonstrates that it is feasible for an undergraduate class to complete a Bd-detection project within a single semester. Such a project not only contributes to Bd research but also promotes conservation education among students through hands-on research experiences. We found Bd infection in only one sample of N. viridescens, but no sign of infection in the rest of the samples. As a relatively high prevalence of Bd has been reported in surrounding areas, our results suggest spatial heterogeneity in Bd occurrence at a regional scale and thus, the need for continued efforts to monitor Bd prevalence.

[Adhesions and abdominal pain]

Adhesions occur with a high incidence after intra-abdominal surgery but can also develop due to infections, radiation or for idiopathic reasons. The formation of adhesions is initiated by tissue damage and is the result of peritoneal tissue repair involving the activation of the inflammatory system and the coagulation cascade. Acute small bowel obstruction is one of the most common complications and should be diagnosed rapidly using clinical examination and radiological imaging. A complete obstruction is life threatening and in a high percentage of patients requires rapid surgical intervention by laparotomy or laparoscopy depending on the clinical situation and the patients history. Despite numerous investigations, there is no reliable, commonly used method to prevent intra-abdominal adhesions. Minimizing tissue damage and foreign body exposure, avoiding spillage of intestinal and biliary contents as well as a laparoscopic approach seem to have a beneficial effect on the formation of intra-abdominal adhesions.

[Intrathoracic esophageal perforation of unknown cause in four horses] Intrathorakale Oesophagusperforation ungeklärter Genese bei vier Pferden

Three horses (age 17 - 23 years) were referred to the equine clinic of the University of Berne due to colic, fever, tachycardia and tachypnea. All horses showed pleural effusion. Clinical findings in 2 of the horses were highly suggestive of an intra-thoracic esophageal perforation. Severe septic pleuropneumonia without suspicion of an esophageal lesion was diagnosed in the 3rd horse. In addition, an 11 year old stallion was referred to the equine clinic for treatment of a presumptive large colon impaction. The horse was given laxatives after nasogastric intubation. Subsequent dramatic clinical deterioration and signs consistent with severe pleuropneumonia suggest that esophageal perforation had occurred when passing the nasogastric tube. All 4 horses were euthanized due to a poor prognosis. Esophageal perforation was diagnosed or confirmed post mortem in all cases. A hypertrophy of the tunica muscularis of the intra-thoracic esophagus was found in 3 of 4 horses.

Experience with a gravitational valve in the management of symptomatic overdrainage in children with shunts

Symptomatic overdrainage in children with shunt-treated hydrocephalus represents one of the more difficult shunt-related diseases and may require repeated surgery. Gravity-assisted valve design has become a standard device to avoid overdrainage in many European pediatric hydrocephalus centers. However, the use of a gravitational valve for relieving symptoms associated with overdrainage has not yet been addressed. The goal of this study was to evaluate the effectiveness of a gravitational valve in the treatment of symptomatic overdrainage in children with shunts.

Inhibition of the human epithelial calcium channel TRPV6 by 2-aminoethoxydiphenyl borate (2-APB)

TRPV6, a highly calcium-selective member of the transient receptor potential (TRP) channel superfamily, is a major pathway for calcium absorption in the fetal and adult body. It is expressed abundantly in the duodenum, the placenta and exocrine tissues. TRVP6 was postulated to contribute to store-operated calcium channel (SOC) activity in certain cell types such as exocrine cells. In this study, we tested 2-APB, a widely used SOC inhibitor on human TRPV6 (hTRPV6) activity using fluorescence imaging, patch clamp and radioactive tracer techniques in transiently and stably transfected HEK293 cells. We found that the basal calcium and cadmium influx was higher in HEK293 cells transfected with hTRPV6 than in non-transfected cells. 2-APB inhibited hTRPV6 activity in both transient and stably transfected cells. This effect was slightly sensitive toward extracellular calcium. The extracellular sodium concentration did not affect the inhibition of hTRPV6 by 2-APB. However, N-methyl-d-glucamine significantly diminished the inhibitory effect of 2-APB presumably through direct interaction with this compound. Furthermore, 2-APB inhibited the activity of TRPV6 orthologs but not human TRPV5. 2-APB may serve as a parental compound for the development of therapeutic strategies specifically targeting the hTRPV6 calcium channel.

[Spontaneous and post-therapeutic cartilage repair: evaluation criteria.]

Articular cartilage has poor reparative capacities, and once damaged cartilage lesions remain chronic and can lead to osteoarthritis. Over the last decade, several innovative therapies have been introduced to promote the regeneration of articular cartilage while sustaining sufficient mechanical stress and permitting a pain free motion. An important measure of outcome is the morphological characterization of the repair tissue in order to allow for cross-study evaluation. The International Cartilage Repair Society has developed a analogue visual scale to quantify repair tissue, which is described in this paper.