Saliva chromogranin A in growing pigs: A study of circadian patterns during daytime and stability under different storage conditions

Salivary chromogranin A (CgA) is considered to be a biomarker of activation of the sympatho-adrenomedullary system, and has recently been proposed as a useful indicator of the acute stress response in pigs. The aim of the present study was to determinate whether salivary CgA concentrations in healthy growing pigs exhibits any circadian pattern during the daytime, and to evaluate its stability under different storage conditions. A total of 80 pigs (40 in spring and another 40 in autumn) of two different ages and genders were used. To establish the circadian pattern, saliva samples were collected at 07.00, 11.00, 15.00 and 19.00 h on two consecutive days. Pooled samples were used for the stability study and were measured on the day of sampling and periodically for up to 360 days later. Samples were stored at 4 °C, ?20 °C or ?80 °C and the effect of repeated freezing and thawing was also evaluated.No circadian pattern was detected for salivary CgA in either season and there were no significant effects of gender or age. However, mean salivary CgA concentrations were significantly higher (P < 0.0001) in the pigs sampled in autumn, compared to those sampled in the spring. Short term storage at 4 °C is recommended for up to 2 days, whereas frozen samples can be stored for 1 year at ?20 °C or ?80 °C, without substantial reduction in CgA values. In addition, samples can be frozen and thawed up to seven times without significant loss of the biomarker.     

Disposition of plasma creatinine in non-azotaemic and moderately azotaemic cats

The objectives of this study were to compare assay methods for plasma creatinine (Pl-creat) in cats and to describe the disposition of creatinine and iohexol in 12 healthy and moderately azotaemic cats. Exogenous creatinine and iohexol were injected simultaneously by intravenous bolus, and repeated blood samples were taken to determine the pharmacokinetic parameters of each marker. Pl-creat was assayed by high-performance liquid chromatography (HPLC), Jaffé and enzymatic methods. The enzymatic method was shown to be more reliable than the Jaffé method. Two stereoisomers, exo- and endo-iohexol were identified. The plasma clearance of creatinine (2.3+/-0.66 ml/min/kg) was significantly higher (P<0.001) than that of exo-iohexol (1.7+/-0.40 ml/min/kg). The volume of distribution (447+/-97 ml/kg) and elimination half-life (181+/-77 min) of creatinine were also higher (P<0.001) than those of exo- and endo-iohexol. The estimated daily endogenous production of creatinine was 65+/-23 mg/kg. None of the pharmacokinetic parameters was changed by the azotaemic status of the animals.     

Soil organic carbon fractions and humic substances are affected by land uses of Caatinga forest in Brazil

Caatinga is a Brazilian dry ecosystem that occupies around 1 million km² and is one of the largest tropical dry forests of the world. About 46% of the area that was originally covered has been deforested. Land use can cause pronounced reduction in soil carbon stocks that play a major role in the global carbon cycle. The objective of this study was to improve our understanding of the effect of land use on oxidizable carbon fractions, total carbon stocks and humic substances in different layers of soil in a Brazilian semi-arid region. We analyzed soils from tropical dry forest (TDF), forest succession with Anadenanthera falcata (ANA), with Tabebuia alba (TAB), secondary scrubby regeneration (SCR), and non-irrigated maize (MS). Forests showed larger fractions of more labile carbon, except for TDF. The most recalcitrant fraction of carbon stock, humin fraction stock, with the different land use decreased by 38–53% compared to TDF. Oxidizable carbon fractions, carbon stocks, and humic fraction stocks were able to differentiate the successional land uses and agricultural cover from TDF, mainly in the 0–5?cm layer. Our results show that changes in land use, especially with ANA forest succession, showed a larger labile carbon fraction, indicating easy decomposition and loss. Our results provide an alternative tool for the management of deforested areas in tropical dry caatinga ecosystems. This would contribute to the conservation of dry forest systems and could serve as guideline for sustainable management of agriculturally impacted caatinga areas.     

New polyphenolic compounds with xanthylium skeletons formed through reaction between (+)-catechin and glyoxylic acid

The reaction between (+)-catechin and glyoxylic acid was studied in a model solution system. The major (+)-catechin carboxymethine-linked dimer was isolated and shown to proceed to new polyphenolic compounds exhibiting absorption maxima around 440 and 460 nm. Three yellow pigments were obtained by incubation of the 8-8 colorless isomer. One was the previously reported xanthylium compound NJ2 with a maximum at 440 nm. The other two, showing absorption maxima at 460 nm, were obtained separately by incubation of the colorless dimer in hydroethanolic or methanolic medium. Structural elucidation of these two new yellow pigments was achieved by means of MS and 1D and 2D NMR techniques and showed that they were, respectively, ethyl and methyl esters of NJ2. The fact that these compounds were not obtained when NJ2 was incubated in hydromethanolic or ethanolic medium showed that esterification took place before the formation of the xanthylium chromophores. The detection of the esterified colorless compounds and the corresponding xanthene intermediates confirmed the postulated mechanism. New pigments exhibiting a strong absorption at 560 nm were also observed.     

Structural observations during androgenic microspore culture of the 4c1 genotype of Zea mays L.

Summary The capacity of the maize genotype 4c1 to regenerate microcalli and embryos from cultured microspores has been examined by comparing various cold pretreatments and culture media, using microspores and pollen at different stages of development. Viability of cultured cells was tested with FDA and their development was traced with light and fluorescence microscopy using DAPI as a nuclear dye.It was found that a pre-incubation of dissected flowers floating in a liquid nutrient medium at 8°C during 10–14 days was most successful for the induction of cell division. Among the developmental stages tested only the microspores appeared to regenerate. Subculture at 25°C in the same liquid medium, supplemented with 0.1 mg/l TIBA, gave highest rates of microspore division, i.e. up to 70% at 4 to 6 days of culture.All pathways described earlier for maize androgenic embryogenesis were observed within the 4c1 genotype. Symmetric divisions occurred in cultured microspores but most frequently asymmetric divisions lead to the formation of microcalli within 12 days of culture. In at least 60% of all dividing microspores cells were derived from the generative nucleus. Microcalli further developed either into loose or compact calli. Compact calli formed embryo-like structures.Abbreviations DAPI 4,6-diamidino-2-phenylindole - Dicamba 3,6-dichloro-2-methoxy benzoic acid - 2,4D 2,4 dichlorophenoxyacetic acid - FDA fluorescein diacetate - PAA phenylacetic acid - TIBA 2,3,5-triiodobenzoic acid - YP medium Yu-Pei basal salt medium