University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Microbial interactions affect sources of priming induced by cellulose

Abstract: The recently developed 3-source-partitioning approach: addition of 14 C labeled organics to soil after C3–C4 vegetation changes, was used to distinguish C sources in three compartments, namely CO 2 , microbial biomass and dissolved organic C (DOC) during decomposition of labeled cellulose. Microbial community structure (based on PLFA composition) and functions (based on enzyme activities and on microbial growth parameters) revealed mechanisms and drivers of priming effects (PE) induced by cellulose addition. 14 C-cellulose input caused negative PE within the first week and was accompanied by fast consumption of unlabelled DOC and its incorporation into microbial biomass. Microbial activation however, was not confirmed by substrate-induced respiration, nor by hydrolytic enzymes activity or by PLFA changes. A remarkable exception was a 2-fold increase in protozoan PLFA. Such an increase indicates that microorganisms feeding on cellulose and on DOC were quickly grazed by protozoans acting as a driver of microbial succession. This experimentally demonstrates the functioning of the microbial interactions: protozoan grazers provided for rapid recycling of nutrients and facilitated the succession of cellulose-degrading microorganisms during the second week of cellulose decomposition. An increase in the activity of cellulolytic enzymes caused short-term real PE accompanied by increase in abundance of slow-growing fungi and G(−) bacteria. Long-term real PE observed between 14 and 60 days after cellulose input was due to decomposition of SOM-originated hemicelluloses by fungi and G(+) bacteria. The CO 2 released by primed soil organic matter (SOM) decomposition was originated mainly from C younger than 12 years (63%) and only 37% were older than 12 years despite the recent and old C contributed almost equally (51 and 49%, respectively) to SOM under Miscanthus giganteus . This indicates that the SOM pools are involved in PE according to their availability. Despite 71% of the applied cellulose-C was sequestered in the soil, the net soil C-gain amounted only for 28% of the applied cellulose-C after factoring in the C losses by the PE. Our study emphasizes the role of food webs in the PE dynamics: cellulose input served as a driver activating the food chain through the microbial loop.

Effects of civility and reasoning in user comments on perceived journalistic quality

Abstract: Journalists are increasingly concerned that offensive and banal user comments on news websites might alienate readers and damage quality perceptions. To explore such presumed effects, we investigated the impact of civility and reasoning (and lack thereof) in user comments on perceptions of journalistic quality. An experiment revealed that unreasoned comments decrease an article’s perceived informational quality, but only in unknown news brands. Incivility in comments had an unconditionally negative effect on the perceived formal quality of an article. Neither civility nor reasoning improved the assessments of journalistic quality, as compared to a comment-free version. On the contrary, we observed a trend showing that the mere presence of comments deteriorates the perceived quality of an article.

Differential Expression of SNMP-1 and SNMP-2 Proteins in Pheromone-Sensitive Hairs of Moths

Abstract: In moths the detection of female-released sex pheromones involves hairlike structures on the male antenna. These long sensilla trichodea usually contain 2-3 chemosensory neurons accompanied by several supporting cells. Previous studies have shown that the pheromone-specific neurons are characterized by a "sensory neuron membrane protein" (SNMP) which is homologous to the CD36 family and localized in the dendrite membrane. By employing the SNMP-2 sequence from Manduca sexta we have isolated cDNAs that encode SNMP-2 proteins from Heliothis virescens (HvirSNMP-2) and Antheraea polyphemus (ApolSNMP-2). To elucidate the topographic and cell type-specific expression of these SNMP subtypes, 2-color in situ hybridization experiments were performed with tissue sections through the male antennae. For H. virescens, a specific probe for the pheromone receptor HR13 was used to identify pheromone-responsive neurons. It was found that HvirSNMP-1 and HR13 were coexpressed in the same cells; in contrast, HvirSNMP-2 was not expressed in HR13 cells but rather in cells that surrounded the HR13 neurons, apparently the supporting cells. A corresponding expression pattern was also found for ApolSNMP-1 and ApolSNMP-2 on the antenna of male A. polyphemus. Our results indicate that SNMP-1s and SNMP-2s are differentially expressed in cells of pheromone-sensitive sensilla and suggest distinct functions for the 2 SNMP subtypes in the olfactory system.