Distribution of viral antigen and development of lesions after experimental infection of calves with a BVDV 2 strain of low virulence.

To examine the virus-host interaction in subclinical bovine viral diarrhea virus (BVDV) infections, the spread of a BVDV 2 strain of low virulence to different organs and the development of lesions were investigated. Eight colostrum-deprived, clinically healthy, 2-3-month-old calves were intranasally inoculated with 10(6) tissue culture infective dose of the naturally occurring BVDV 2 strain 28508-5 of low virulence, and 2 served as controls. Two calves each were euthanized at days 3, 6, 9, and 13 postinoculation (pi). Representative tissues were processed for histology and immunohistology. Signs of overt clinical disease were absent. However, a mild temperature elevation at days 7 or 8 pi and a moderate decrease of circulating lymphocytes occurred in all inoculated calves. The BVDV antigen was detected at day 3 pi in several lymphoid tissues. At day 6 pi, BVDV antigen was found widespread in lymphoid tissues and multifocally in intestinal epithelial cells but was associated with no or subtle lesions only. At day 9 pi, much less BVDV antigen was detectable, but there was severe depletion of lymphoid tissues. At day 13 pi, BVDV antigen had been cleared from most lymphoid tissues that were at variable phases of depletion and recovery. In conclusion, the BVDV strain of low virulence spread to lymphoid tissues and intestinal epithelial cells but was rapidly eliminated. Transient depletion of lymphoid tissues was followed by recovery.     

Phosphorus speciation in sediments from the Baltic Sea,evaluated by a multi-method approach

Journal of Soils and Sediments - Phosphorus (P) is a crucial element for living organisms at both land and sea, but simultaneously, it can cause environmental problems especially in marine...     

The effect of stage of maturity and storage on the respiratory quotient of potato tubers

Summary A respiratory quotient for the tuber, during development, of about 1,0 is succeeded by a variable quotient during the senescence and death of the foliage, harvesting, and the early weeks of storage. Later a quotient of about 1,0 is again observed, but later still there is a considerable increase above this value, suggesting a greater participation of an anaerobic cycle or cycles.

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Zusammenfassung Der Atmungsquotient der Knolle liegt w?hrend der Entwicklung ungef?hr bei 1,0. Diesem folgt w?hrend des Alterns und Absterbens des Krautes, zur Zeit der Ernte und in den ersten Wochen der Lagerung ein ver?nderlicher Quotient. Sp?ter kann wieder ein Quotient von 1,0 beobachtet werden. Noch sp?ter steigt dieser Wert erheblich an, was auf eine st?rkere Beteiligung eines oder mehrerer anaerobischer Atmungszyklen schliessen l?sst.

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Résumé A un quotient respiratoire du tubercule, pendant le développement, d'environ 1, succède un quotient variable durant la sénescence et la mort du feuillage, la récolte et les premières semaines de la conservation. Plus tard on observe de nouveau un quotient respiratoire de 1 environ, mais, plus tard encore, il y a un accroissement considérable au-dessus de cette valeur, faisant supposer une participation plus grande d'un ou de plusieurs cycles anaérobies.

     

Langerhans cells facilitate epithelial DNA damage and squamous cell carcinoma

Polyaromatic hydrocarbons (PAHs) are prevalent, potent carcinogens, and 7,12-dimethylbenz[a]anthracene (DMBA) is a model PAH widely used to study tumorigenesis. Mice lacking Langerhans cells (LCs), a signatory epidermal dendritic cell (DC), are protected from cutaneous chemical carcinogenesis, independent of T cell immunity. Investigation of the underlying mechanism revealed that LC-deficient skin was relatively resistant to DMBA-induced DNA damage. LCs efficiently metabolized DMBA to DMBA-trans-3,4-diol, an intermediate proximal to oncogenic Hras mutation, and DMBA-treated LC-deficient skin contained significantly fewer Hras mutations. Moreover, DMBA-trans-3,4-diol application bypassed tumor resistance in LC-deficient mice. Additionally, the genotoxic impact of DMBA on human keratinocytes was significantly increased by prior incubation with human-derived LC. Thus, tissue-associated DC can enhance chemical carcinogenesis via PAH metabolism, highlighting the complex relation between immune cells and carcinogenesis.     

A MADS-box gene necessary for fruit ripening at the tomato ripening-inhibitor (rin) locus

Tomato plants harboring the ripening-inhibitor (rin) mutation yield fruits that fail to ripen. Additionally, rin plants display enlarged sepals and loss of inflorescence determinacy. Positional cloning of the rin locus revealed two tandem MADS-box genes (LeMADS-RIN and LeMADS-MC), whose expression patterns suggested roles in fruit ripening and sepal development, respectively. The rin mutation alters expression of both genes. Gene repression and mutant complementation demonstrate that LeMADS-RIN regulates ripening, whereas LeMADS-MC affects sepal development and inflorescence determinacy. LeMADS-RIN demonstrates an agriculturally important function of plant MADS-box genes and provides molecular insight into nonhormonal (developmental) regulation of ripening.