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.

A 7,272-year tree-ring chronology for western Europe

Abstract: Long tree-ring chronologies provide a unique calendrical record that is of value for archaeological dating, climatic and post-glacial studies. They also form a standard for the calibration of the radiocarbon time scale. The world's longest continuous tree-ring chronology is based on the bristlecone pine (Pinus aristata and Pinus longaeva) growing in the White Mountains of California1–3. The great age of living and sub-fossil trees of this species enabled a continuous tree-ring sequence of 8,681 years to be established, providing absolutely dated wood samples for the first radiocarbon calibration4,5. We have now established an unbroken west European tree-ring sequence spanning the past 7,272 years.

Bean pathogenesis-related (PR) proteins deduced from elicitor-induced transcripts are members of a ubiquitous new class of conserved PR proteins including pollen allergens.

Abstract: We have searched for induced transcripts in a cDNA library derived from bean cell suspension cultures treated with an elicitor fromColletotrichum lindemuthianum. Six independently isolated cDNAs corresponding to rapidly induced small mRNAs have been classified by their DNA sequence and slightly different induction behaviour into two groups. 5′- and 3′-untranslated regions exhibit little similarity, but the deduced small acidic proteins designated PvPR1 and PvPR2 are 89% identical. No relationship was found with the well-characterized PR1 proteins from tobacco. However, the PvPR proteins are closely related to pI49 in pea (64% identity), pSTH2 in potato (41 % identity) and PcPR1-1 in parsley (39% identity), which are also induced in response to elicitor or microbial attack. Moreover, a major pollen allergen in birch (Betv1) has a 44% identity with PvPR1 proteins. These similarities establish a ubiquitous class of conserved defense-related proteins and suggest a common yet still unknown function. Southern blot analysis indicates that PvPR protein gene organization is highly complex with an estimated copy number of more than 12 genes.

Preparation and purification of DNA from insects for AFLP analysis

Abstract: Analysis of amplified fragment length polymorphism (AFLP) has the potential to become a powerful new DNA fingerprinting technique for studying genetic relationships and genetic diversity in arthropods. Since DNA of high quality is a crucial prerequisite for AFLP analysis we evaluated the applicability of six protocols (one fast and four complex methods with phenol-chloroform treatments as well as one CTAB-based method) for extracting DNA from insect material and three additional DNA purification steps. The most rapid DNA isolation method did not produce DNA suitable for AFLP analysis. Among four complex methods tested, two protocols resulted in comparatively low yields of DNA that was therefore not used as template for AFLP analysis. The other two complex methods with phenol treatments and a CTAB-based DNA extraction protocol provided DNA suitable for AFLP assay. An additional purification of the DNA using spermine precipitation revealed a few extra bands in an AFLP gel that were masked in unpurified DNA. Therefore spermine precipitation is recommended for AFLP templates.