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R Zettl

Publications and source records attributed to R Zettl.

25 records · Page 2Linked to original sources
PubMed1994

Photoaffinity labeling of Arabidopsis thaliana plasma membrane vesicles by 5-azido-[7-3H]indole-3-acetic acid: identification of a glutathione S-transferase.

We used 5-azido-[7-3H]indole-3-acetic acid (5-azido-[7-3H]IAA), a photoaffinity analogue of the plant hormone indole-3-acetic acid (IAA), to search for auxin-binding proteins in Arabidopsis thaliana membranes. We identified an auxin-binding protein with a molecular mass of 24 kDa (Atpm24) in microsomes as well as in plasma membrane vesicles. Atpm24 was solubilized by 1% Triton X-100 and partially purified. A cDNA clone (Atpm24.1) corresponding to Atpm24 was isolated. The amino acid sequence predicted from the Atpm24.1 cDNA contains 212 amino acid residues with a relative molecular mass of 24,128 Da. Data base searches revealed that the predicted protein has homology to glutathione S-transferases (GSTs; EC 2.5.1.18). When Atpm24.1 was expressed in Escherichia coli, we found a high level of GST activity in the bacterial extracts. We have analyzed the substrate specificity of this protein and found that cumene hydroperoxide and trans-stilbene oxide but not trans-cinnamic acid or IAA-CoA were substrates. A role for this GST in physiological processes of plants is discussed.

Affinity Labels↗
PubMed1994

[Operation planning of secondary interventions after polytrauma].

A prospective study of 135 secondary operations (> 24 h after trauma) in patients with multiple injuries (ISS 40.6 pts) was performed to determine specific and unspecific indicators of the inflammatory response that may indicate the degree of risk of postoperative organ failure in these patients. On the morning of the operation each patients' data were recorded and blood samples were collected. Patients were divided in those in whom respiratory, renal and/or hepatic failure developed or preexisting organ failure worsened by more than 20% from baseline within 2 days after the operation and those who had no complications. In 29 patients who were operated upon between 24 and 72 h after trauma only the pO2/FiO2 ratio allowed discrimination between the two groups. The overall accuracy of this parameter as a predictor of postoperative organ failure was 83%, with a sensitivity of 78% and a specificity of 85%. In 106 patients with secondary operations later than 72 h after trauma, neutrophil elastase, C-reactive protein and platelet count revealed the highest predictive accuracy, with cut-off values of 250 ng/ml, 11 mg/dl and 180 x 10(6)/ml, respectively. The combined accuracy of these three parameters in prediction of postoperative organ failure was 79% (sensitivity 73%, specificity 83%). In this group of patients the pO2/FiO2 ratio was of less value and blood pressure, heart rate, renal function parameters, lactate and coagulation parameters were of no value.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Reaction↗
PubMed1992

An auxin-binding protein is localized to the plasma membrane of maize coleoptile cells: identification by photoaffinity labeling and purification of a 23-kda polypeptide.

Plasma membrane vesicles were isolated from maize (Zea mays L.) coleoptile tissue by aqueous two-phase partitioning and assayed for homogeneity by the use of membrane-specific enzymatic assays. Using 5-azido-[7-3H]indole-3-acetic acid ([3H]N3IAA), we identified several IAA-binding proteins with molecular masses of 60 kDa (pm60), 58 kDa (pm58), and 23 kDa (pm23). Using Triton X-114, we were able to selectively extract pm23 from the plasma membrane. We show that auxins and functional analogues compete with [3H]N3IAA for binding to pm23. We found that PAB130, a polyclonal antibody raised against auxin-binding protein 1 (ABP-1), recognized ABP-1 as well as pm23. This suggests that pm23 shares common epitopes with ABP-1. In addition, we identified an auxin-binding protein with a molecular mass of 24 kDa (pm24), which was detected in microsomal but not in plasma membrane vesicle preparations. Like pm23 this protein was extracted from membrane vesicles with Triton X-114. We designed a purification scheme allowing simultaneous purification of pm23 and pm24. Homogeneous pm23 and pm24 were obtained from coleoptile extracts after 7000-fold purification.

Journal Article↗
PubMed1992

5'-Azido-[3,6-3H2]-1-napthylphthalamic acid, a photoactivatable probe for naphthylphthalamic acid receptor proteins from higher plants: identification of a 23-kDa protein from maize coleoptile plasma membranes.

1-Naphthylphthalamic acid (NPA) is a specific inhibitor of polar auxin transport that blocks carrier-mediated auxin efflux from plant cells. To allow identification of the NPA receptor thought to be part of the auxin efflux carrier, we have synthesized a tritiated, photolabile NPA analogue, 5'-azido-[3,6-3H2]NPA ([3H2]N3NPA). This analogue was used to identify NPA-binding proteins in fractions highly enriched for plasma membrane vesicles isolated from maize coleoptiles (Zea mays L.). Competition studies showed that binding of [3H2]N3NPA to maize plasma membrane vesicles was blocked by nonradioactive NPA but not by benzoic acid. After incubation of plasma membrane vesicles with [3H2]N3NPA and exposure to UV light, we observed specific photoaffinity labeling of a protein with an apparent molecular mass of 23 kDa. Pretreatment of the plasma membrane vesicles with indole-3-acetic acid or with the auxin-transport inhibitors NPA and 2,3,5-triiodobenzoic acid strongly reduced specific labeling of this protein. This 23-kDa protein was also labeled by addition of 5-azido-[7-3H]indole-3-acetic acid to plasma membranes prior to exposure to UV light. The 23-kDa protein was solubilized from plasma membranes by 1% Triton X-100. The possibility that this 23-kDa polypeptide is part of the auxin efflux carrier system is discussed.

Journal Article↗
PubMedDate not supplied

[Hallux valgus: a therapy concept and its outcome from 1993 to 1996].

INTRODUCTION: Aim of this study is to present the treatment concept and the results of hallux valgus surgery of our department. PATIENTS AND METHODS: The criteria for decision making are 1st intermetatarsal angle, congruency of the first metatarsophalangeal joint and sesamoid position. According to our concept we performed between 1993 and 1996 42 Chevron osteotomies for mild, 138 Chevron with lateral soft tissue release (Chevron + LSR) for moderate and 93 basal crescentic (Mann) osteotomies with lateral soft tissue release for severe hallux valgus deformities. RESULTS: 31 Chevron, 118 Chevron with lateral soft tissue release and 80 basal crescentic osteotomies (Mann) were seen at an average follow up of 19 months (12-29) after a Chevron, respectively. 16 months (12-43) after Chevron with lateral soft tissue release and 18 months (12-32) after a basal crescentic osteotomy. 83% of all patients classified the results of the surgery as "very satisfactory" and "satisfactory". The average hallux valgus angle was corrected from preoperatively. 25.3 degrees (Chevron), 29.9 degrees (Chevron + LSR) and 41.8 degrees (Mann) to 16.5 degrees (Chevron), 12.1 degrees (Chevron + LSR) and 14.1 degrees (Mann) at final follow up, the average first intermetatarsal angle was corrected from preoperatively 12.1 degrees (Chevron), 14.0 degrees (Chevron + LSR) and 17.4 degrees (Mann) to 7.9 degrees (Chevron), 5.8 degrees (Chevron + LSR) and 7.8 degrees (Mann) at final follow up. CONCLUSION: Our analysis of the three osteotomies revealed that with this differentiated concept we were able to achieve excellent and good results in more than 80% of our patients. Only with a treatment plan that includes different procedures to address the various stages of hallux valgus can one achieve the optimum result for the patient.

Adult↗