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Rocholl M, Ludewig M, Skudlik C, Wilke A. [Occupational skin cancer : Prevention and recommendations for UV protection as part of the treatment approved by the public statutory employers' liability insurance]. Hautarzt 2019; 69:462-470. [PMID: 29704211 DOI: 10.1007/s00105-018-4171-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In Germany, approximately 2 to 3 million employees work in outdoor professions. They are exceptionally exposed to solar ultraviolet (UV) radiation for a large part of their daily working time. Cumulative UV exposure is associated with a significantly increased risk of skin cancer for outdoor workers from various occupational groups (e. g. landscape and horticulture, agriculture and forestry, fisheries and seafaring, construction and trade, as well as sports teachers, lifeguards and mountain guides). Since 1 January 2015, squamous cell carcinoma and multiple actinic keratosis due to natural UV radiation can be recognised as occupational disease No. 5103 by the German statutory social accident insurance. Reducing cumulative UV exposure is the main prevention aspect of this type of skin damage. Therefore, technical, organisational and personal UV protection measures should be implemented in the professional and private environment. Moreover, they have to be regularly used in an appropriate way. In addition to guideline-oriented therapy, training and counselling of patients with already existing actinic skin damage or a recognised occupational disease No. 5103 is therefore of particular importance. The focus should be on improving the individual UV protection behaviour. This article gives an overview of current recommendations for UV protection in the professional environment. It outlines possible solutions for patient counselling in terms of UV protection in everyday practice.
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Affiliation(s)
- M Rocholl
- Abteilung Dermatologie, Umweltmedizin und Gesundheitstheorie, Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland. .,Institut für interdisziplinäre Dermatologische Prävention und Rehabilitation (iDerm), Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland.
| | - M Ludewig
- Abteilung Dermatologie, Umweltmedizin und Gesundheitstheorie, Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland.,Institut für interdisziplinäre Dermatologische Prävention und Rehabilitation (iDerm), Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland
| | - C Skudlik
- Abteilung Dermatologie, Umweltmedizin und Gesundheitstheorie, Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland.,Institut für interdisziplinäre Dermatologische Prävention und Rehabilitation (iDerm), Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland
| | - A Wilke
- Abteilung Dermatologie, Umweltmedizin und Gesundheitstheorie, Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland.,Institut für interdisziplinäre Dermatologische Prävention und Rehabilitation (iDerm), Universität Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Deutschland
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Schares G, Bangoura B, Randau F, Goroll T, Ludewig M, Maksimov P, Matzkeit B, Sens M, Bärwald A, Conraths F, Opsteegh M, Van der Giessen J. High seroprevalence of Toxoplasma gondii and probability of detecting tissue cysts in backyard laying hens compared with hens from large free-range farms. Int J Parasitol 2017; 47:765-777. [DOI: 10.1016/j.ijpara.2017.07.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/04/2017] [Accepted: 07/11/2017] [Indexed: 01/05/2023]
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Bangoura B, Zöller B, Koethe M, Ludewig M, Pott S, Fehlhaber K, Straubinger R, Daugschies A. Experimental Toxoplasma gondii oocyst infections in turkeys (Meleagris gallopavo). Vet Parasitol 2013; 196:272-7. [DOI: 10.1016/j.vetpar.2013.03.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 10/27/2022]
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Pott S, Koethe M, Bangoura B, Zöller B, Daugschies A, Straubinger RK, Fehlhaber K, Ludewig M. Effects of pH, sodium chloride, and curing salt on the infectivity of Toxoplasma gondii tissue cysts. J Food Prot 2013; 76:1056-61. [PMID: 23726205 DOI: 10.4315/0362-028x.jfp-12-519] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Toxoplasma gondii is one of the most common zoonotic parasites in the world. The parasite causes no or mild symptoms in immunocompetent humans. However, a high potential hazard exists for seronegative pregnant women and immunocompromised patients. The consumption of meat containing tissue cysts or oocyst-contaminated vegetables and fruits or the handling of cat feces poses a high risk of infection with T. gondii. It is known that raw minced meat, raw fresh sausages, and locally produced raw meat products are possible causes of T. gondii infection. The infectivity of T. gondii tissue cysts in meat products depends, among other factors, on the pH and the salt concentration. Therefore, the impact of these two factors on the tissue cysts was examined. For this purpose, dissected musculature and brain from experimentally infected mice (donor mice) were placed in a cell culture medium (RPMI 1640). The medium was adjusted to different pH values (pH 5, 6, and 7) with lactic acid and to different salt concentrations (2.0, 2.5, and 3.0%) with sodium chloride (NaCl) or nitrite-enriched curing salt (NCS) for the various tests. After storage at 4°C for different time periods, the materials were fed to bioassay mice. Later, the brains were examined for presence of T. gondii to assess the infectivity. The data show that T. gondii tissue cysts have a high pH tolerance. Cysts were infectious in the muscle for up to 26 days (pH 5). In contrast to their tolerance to pH, cysts were very sensitive to salt. Muscle cysts survived at an NaCl concentration of up to 2.0% only, and for no longer than 8 days. At NaCl concentrations of 2.5 and 3.0%, the cysts lost their infectivity after 1 day. When NCS instead of NaCl was used under the same conditions, T. gondii muscle cysts retained infectivity for only 4 days at 2.0%. Consequently, NCS (NaCl plus 0.5% nitrite) has a stronger effect on T. gondii cysts than does common table salt. Sausages produced with low NaCl concentration and short contact times pose a potential risk for susceptible individuals.
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Affiliation(s)
- S Pott
- Institute of Food Hygiene, University of Leipzig, An den Tierkliniken 1, 04103 Leipzig, Germany
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Mitterer-Istyagin H, Ludewig M, Bartels T, Krautwald-Junghanns ME, Ellerich R, Schuster E, Berk J, Petermann S, Fehlhaber K. Examinations on the prevalence of footpad lesions and breast skin lesions in B.U.T. Big 6 fattening turkeys in Germany. Part II: Prevalence of breast skin lesions (breast buttons and breast blisters). Poult Sci 2011; 90:775-80. [PMID: 21406362 DOI: 10.3382/ps.2010-01142] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This project involves the prevalence of breast skin alterations (breast buttons, blisters, purulent bursitis) in male and female fattened turkeys (British United Turkeys Big 6) from conventional intensive farming. In this case, 24 turkey farms across Germany and 11,860 turkeys (5,740 toms, 6,120 hens) were clinically examined, and 16,200 birds (8,400 hens, 7,800 toms) were evaluated on slaughter lines at 7 turkey abattoirs. Each turkey farm included examination of at least 3 consecutive fattening cycles. Especially in the meat examinations, breast skin alterations were a frequent discovery, particularly in the form of breast buttons. The turkey toms exhibited a prevalence of 27.15%, and the toms were affected significantly more frequently (P < 0.001) by these variations than the turkey hens (7.77%). It is possible that the higher BW of the male specimens leads to increased lying times and is therefore connected with more severe strain on the breast region. The increased fattening period of the turkey toms (slaughtering at wk 21 to 22 of life) vs. the female specimens (slaughtering at wk 15 to 17 of life) must be discussed as a cause. Breast blisters and bursitis sternalis were discovered with a prevalence of 7.36 and 1.24% in toms and more seldom in hens, at 0.30% and 0.15%. Large differences in prevalence were partially recognizable between individual farms as well as between the 3 fattening cycles on a farm. Breast buttons and breast blisters are pathological skin variations for which the etiology is multifactorial. Clear correlations between the prevalence of breast skin alterations and the manner of rearing the birds were not able to be determined. An improvement in this situation, which is considered very problematic from the perspective of bird protection and economics, may be achieved only via cooperation to achieve optimized rearing methods, management, and breeding practices.
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Affiliation(s)
- H Mitterer-Istyagin
- Institute of Food Hygiene, Faculty of Veterinary Medicine, University of Leipzig, Germany.
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Krautwald-Junghanns ME, Ellerich R, Mitterer-Istyagin H, Ludewig M, Fehlhaber K, Schuster E, Berk J, Petermann S, Bartels T. Examinations on the prevalence of footpad lesions and breast skin lesions in British United Turkeys Big 6 fattening turkeys in Germany. Part I: prevalence of footpad lesions. Poult Sci 2011; 90:555-60. [PMID: 21325225 DOI: 10.3382/ps.2010-01046] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present study demonstrates the prevalence of footpad lesions in turkeys and their level of expression in both live birds and in carcasses. In clinical investigations of 11,860 turkeys (5,740 males, 6,120 females) of the strain British United Turkeys Big 6, individuals of all the observed flocks showed alterations to the plantar skin. In general, the degree and severity of skin alterations were higher in the 16th week of life than in the 6th or 11th week of life. Epithelial necrosis, however, was already apparent in about 45% of individuals in the 6th week of life. At this point, deep lesions on the footpad surface were still rare findings. In the 11th week of life, such skin changes were apparent in 14.7% of males and 25.7% of hens. In general, the feet of male turkeys were less affected by footpad damage than those of females in the subsequent fattening period. In hens, the prevalence of lesions of the footpads at wk 16 of age was 60.0%, almost twice as high as in males of the same age group (33.8%). A comparison of the findings from the right and left feet showed that the state of the 2 extremities was correlated (Spearman correlation: r = 0.830). During the visual inspection of 16,200 slaughtered turkeys (7,800 males, 8,400 hens), almost all carcasses studied showed alterations to the footpad skin. Only 2.1% of males and 0.6% of females were without lesions. The most frequently observed lesions measured up to 2 cm in diameter (males: 59.2%; hens: 57.7%). Pronounced skin lesions of the footpad (males: 21.1%; females: 29.5%) and necrosis of the superficial epithelium (males: 17.5%; females: 12.1%) were less common. Foot abscesses were diagnosed only sporadically (males: 0.1%; females: 0.1%).
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Ricke J, Thormann M, Rühl R, Jungnickel K, Ludewig M, Pech M, Peters N, Wieners G, Fischbach F. MR-fluoroskopisch geführte Brachytherapie hepatozellulärer Karzinome an einem offenen Hochfeld-MRT: Sicherheit und Effektivität. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1252549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Jungnickel K, Lohfink K, Bunke J, Ludewig M, Ricke J, Fischbach F. Evaluation der online Thermometrie während MR-gestützter RFA zur Prognose des Ablationserfolges. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1252923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Ricke J, Thormann M, Mohnike K, Jungnickel K, Ludewig M, Peters N, Wieners G, Pech M, Fischbach F. Sicherheit und Effektivität der Brachytherapie kolorektaler Karzinome unter MR-Fluoroskopie an einem offenen Hochfeld-MRT. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1252550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Ricke J, Thormann M, Pech M, Wybranski C, Gaffke G, Wieners G, Jungnickel K, Ludewig M, Fischbach F. Bildgeführte Brachytherapie unter MR-Fluoroskopie: Technik und erste Ergebnisse. ROFO-FORTSCHR RONTG 2009. [DOI: 10.1055/s-0029-1221592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Jungnickel K, Gaffke G, Lohfink K, Fischbach F, Will K, Bunke J, Ludewig M, Großer O, Omar A, Ricke J. MR-Thermometrie während Radiofrequenzablation in vitro am offenen 1.0 Tesla MRT. ROFO-FORTSCHR RONTG 2009. [DOI: 10.1055/s-0029-1221313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zöller G, Waßmann K, Ludewig M, Ringert RH. Extrakorporale Stoßwellenlithotripsie eines Nierenbeckenausgußsteines bei einem 15 Monate alten Säugling. Aktuelle Urol 2008. [DOI: 10.1055/s-2008-1060632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kopka J, Ludewig M, Müller-Röber B. Complementary DNAs encoding eukaryotic-type cytidine-5'-diphosphate-diacylglycerol synthases of two plant species. Plant Physiol 1997; 113:997-1002. [PMID: 9085581 PMCID: PMC158221 DOI: 10.1104/pp.113.3.997] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cytidine diphosphate (CDP)-diacylglycerol synthase (cytidine triphosphate:phosphatidate cytihyltransferase, EC 2.7.7.41) catalyzes the formation of CDP-diacylglycerol, which is the precursor of phosphatidylinositol, phosphatidylglycerol, and cardiolipin. We report the first cloning, to our knowledge, of two plant cDNAs, StCDS1 and AtCDS1, coding for CDP-diacylglycerol synthase from potato (Solanum tuberosum) and Arabidopsis thaliana, respectively. The two proteins belong to the eukaryotic type of CDP-diacylglycerol synthase and contain eight predicted transmembrane-spanning domains. We analyzed gene expression in shoot and root tissues of potato plants and demonstrated enzyme activity by expression of N-terminally truncated, recombinant StCDS1 in Escherichia coli.
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Affiliation(s)
- J Kopka
- Institut für Genbiologische Forschung Berlin, Germany
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Ludewig M, Weidner W, Ringert RH. [Percutaneous drainage of renal and perirenal abscesses. 2 case reports]. Fortschr Med 1994; 112:337-40. [PMID: 7959506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Undetected and untreated renal and perinephritic abcesses are associated with high morbidity and mortality rates. Thanks to the technique of ultrasonography and computed tomography, it is now possible to identify a suspected abscess early on. As treatment, percutaneous drainage has proved both effective and associated with only few side effects. Two cases are reported, one with renal, one with perinephritic abscess, both of which were successfully treated with percutaneous drainage.
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Affiliation(s)
- M Ludewig
- Klinik und Poliklinik für Urologie, Universität Göttingen
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Abstract
Multiple sclerosis is a disease both of the CNS compartment in which a localized immune response occurs, and of the peripheral immune compartment. The causative agent is unknown, though viruses are suspected to be among the candidates. Here a hypothesis is proposed, that apart from viruses, also activated granulocytes of the host might trigger a sensitization against self, insofar as they are suited to modify self-proteins. The modification results from the action of endogenous o-quinones which are generated by activated granulocytes. o-quinones are chemically reactive and couple to proteins producing new epitopes. Modified self-proteins then may sensitize the immune system or break the immune tolerance. Granulocytes thus not only effectively eliminate pathogens, but cause damage to tissues of the host, by proteinases as described in inflammation, or by endogenous o-quinones as proposed here for multiple sclerosis and its models.
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Affiliation(s)
- M Ludewig
- Institute of Biochemistry, Martin-Luther-University Halle-Wittenberg, Germany
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Zöller G, Ludewig M, Kallerhoff M, Zappel H. [Extracorporeal shockwave lithotripsy in the treatment of pediatric urolithiasis]. Monatsschr Kinderheilkd 1991; 139:768-71. [PMID: 1775143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The 2nd generation lithotripter LITHOSTAR plus was used for extracorporeal shock wave lithotripsy of 9 kidney stones, 2 ureteral calculi and 2 bladder stones in 10 children 15 months to 17 years old. Ultrasonic stone localization was used in 2 children, x-ray guided stone localization in 8 children. General anesthesia was necessary in 6 children. A stone free rate of 60% was achieved after 1 treatment. Except for one 14-year old boy no adjuvant procedures like percutaneous nephrostomy or ureteral stents were applied. No major complications were encountered.
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Affiliation(s)
- G Zöller
- Urologische Klinik, Georg-August-Universität, Göttingen
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Zöller G, Wassmann K, Ludewig M, Blech M, Ringert RH. [Extracorporeal shockwave lithotripsy with combined ultrasound and roentgenologic calculus localization. Initial clinical experiences with the Lithostar plus]. Urologe A 1990; 29:338-41. [PMID: 2291259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Since the introduction of extracorporeal shock wave lithotripsy for non-invasive treatment of renal and ureteral stones, lithotripter units have relied on either fluoroscopic or ultrasound stone localization. While ultrasound stone localization reduces X-ray exposure and facilitates treatment of radiolucent renal stones, fluoroscopic stone localization is superior in the detection of ureteral stones. Since April 1989 we have been using the Lithostar plus, a new lithotriptor system, which provides both fluoroscopic and ultrasound stone localization. After treatment of 108 patients, the initial data suggest that this system combines the advantages of both localization principles, while being as efficient as other second-generation lithotriptor units in bringing about the disintegration of renal and ureteral stones.
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Affiliation(s)
- G Zöller
- Urologische Universitätsklinik Göttingen
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Ludewig M, Dörffling K, Seifert H. Abscisic acid and water transport in sunflowers. Planta 1988; 175:325-333. [PMID: 24221869 DOI: 10.1007/bf00396337] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/1987] [Accepted: 02/17/1988] [Indexed: 06/02/2023]
Abstract
The role of abscisic acid (ABA) in the transport of water and ions from the root to the shoot of sunflower plants (Helianthus annuus) was investigated by application of ABA either to the root medium or to the apical bud. The exudation at the hypocotyl stump of decapitated seedlings was measured with and without hydrostatic pressure (0-0.3 MPa) applied to the root. All ABA concentrations tested (10(-10)-10(-4) mol·l(-1)) promoted exudation. Maximal amounts of exudate (200% of control) were obtained with ABA at 10(-6)·mol·l(-1) and an externally applied pressure of 0.1 MPa. The effect was rapid and long-lasting, and involved promotion of ion release to the xylem (during the first hours) as well as an increase in hydraulic conductivity. Abscisic acid applied to the apical bud had effects similar to those of the rootapplied hormone. Increased rates of exudation were also obtained after osmotic stress was applied to the root; this treatment increased the endogenous level of ABA in the root as well as in the shoot. Water potentials of the hypocotyls of intact plants increased when the roots were treated with ABA at 5°C, whereas stomatal resistances were lowered. The results are consistent with the view that ABA controls the water status of the plant not only by regulating stomatal transpiration, but also by regulating the hydraulic conductivity of the root.
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Affiliation(s)
- M Ludewig
- Institut für Allgemeine Botanik, Universität Hamburg, Ohnhorststrasse 18, D-2000, Hamburg 52, Federal Republic of Germany
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Abstract
Cells of Acinetobacter calcoaceticus strain 69-V contain an aminopeptidase that cleaves L-leucine amide, leucylglycine or leucine hydrazide with high efficiency. Leucine 4-nitroanilide and hydrazide are hydrolyzed to less than 0.1% and 1%, resp. of leucine amide. Grown on acetate-NH4+ medium the activity of the enzyme in the cytoplasm is increased 5-fold compared with cells grown on a casamino acid medium or on yeast extract. In these cases the specific activity of the unpurified enzyme is about 5 nkat/mg for the cytoplasmic and membrane-bound enzyme species as well. Up to 30% of the aminopeptidase activity were found mainly in intracytoplasmic membranes, less in cytoplasmic membranes and only traces in outer membranes, presumably as contaminations. It is solubilized by detergents but not by high salt concentrations. An addition of antipain or Z-Ala2-Phe-CH3 before cell rupture did not change the distribution of the enzyme. A mixture of EDTA and 1.10-phenanthroline diminished the membrane-bound enzyme from 11.4% to 4.3% and leupeptin or E-64 increased it to 20%. The enzyme is regarded as leucine aminopeptidase (LAP) bound to intracytoplasmic membranes.
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Affiliation(s)
- M Ludewig
- Institut für Biochemie der Martin-Luther-Universität, Halle/Salle, DDR
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Tietz A, Ludewig M, Dingkuhn M, Dörffling K. Effect of abscisic acid on the transport of assimilates in barley. Planta 1981; 152:557-561. [PMID: 24301160 DOI: 10.1007/bf00380827] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/1981] [Accepted: 05/13/1981] [Indexed: 06/02/2023]
Abstract
The effect of abscisic acid (ABA) on assimilate transport in barley was investigated in two parallel experiments. First, the effect upon [(14)C]sucrose transport from the flag leaf to the ear of a single ABA application made at different stages of growth of the fruits was investigated; the effect was measured 24 h after treatment. Second, the effect of a single application of ABA made at the same stages of growth as above on grain weight of the mature plant was investigated. In both types of experiments ABA was applied once to the ear of different plants as an aqueous solution (10(-3)-10(-5) M), one to five weeks after anthesis. [(14)C] sucrose was applied by means of agar blocks. Parallel to these experiments, the endogenous content of ABA was investigated in the developing grains. When ears were treated with ABA two or four weeks after anthesis, an increase of up to 70% in the (14)C-transport from the flag leaf to the ear was observed within a 24-h period after treatment (short duration experiments). At these growth stages the endogenous concentrations of ABA were low. In sharp contrast, ABA, especially in a concentration of 10(-3) M, decreased (14)C-import from the flag leaf when applied three weeks after anthesis. At this stage the endogenous ABA content had reached its maximum. Long duration experiments with a single application of ABA to the car two weeks after anthesis resulted in a marked increase of weight per thousand kernels. ABA applications made earlier or later than two weeks after anthesis either reduced the grain weight or had no effect. It is concluded that ABA is involved in the regulation of assimilate transport from the leaves to the grains, possibly by influencing the unloading of sieve tubes in the ears. Promotion or inhibition of assimilate import by exogenously applied ABA may depend on the developmental stage of the grains and on the endogenous ABA level.
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Affiliation(s)
- A Tietz
- Institut für Allgemeine Botanik der Universität Hamburg, Jungiusstraße 6, D-2000, Hamburg 36, Federal Republic of Germany
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Abstract
In the present paper the reactivity of histidyl residues of leucine aminopeptidase from bovine eye lens was studied by dye-sensitized photooxidation and by carbethoxylation of the enzyme protein using diethylpyrocarbonate. Of all the different amino acids modified by photooxidation only histidine is connected with the enzymic acticity, whereas tyrosine seems to be involved in structure stabilization. By changing the pH and varying the effectors (Mg2+ and/or dodecylsulfate) of the reaction mixture a different number of histidyl residues of the enzyme protein is caused to react with diethylpyrocarbonate. No secondary reactions with tyrosyl or tryptophyl residues could be observed by spectrophotometric investigations. The enzyme modified by one of the above-mentioned methods shows changes in the capacity of Mn2+ binding measured by autoradiography as well as in the degree of enhancement of enzymic activity by Mn2+ or Mg2+ ions. Of the 48 histidyl residues of the enzyme (Mr = 326000) up to 2 histidyl residues per subunit (Mr = 54000) may be involved in Mn2+ or Mg2+ binding and up to 4 histidyl residues have a strong influence on Zn2+ binding.
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Ludewig M, Lasch J, Kettmann U, Frohne M, Hanson H. The influence of anions on enzymic activity and metal cation binding of leucine aminopeptidase. Enzymologia 1971; 41:59-67. [PMID: 4329993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Hanson H, Glässer D, Ludewig M, Mannsfeldt HG, John M. [Structural and activity identity of leucine aminopeptidase from pig kidney and bovine lens, and comparison with particulate aminopeptidase from pig kidney]. Hoppe Seylers Z Physiol Chem 1967; 348:689-704. [PMID: 5601648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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