Establishment of proliferative cell nuclear antigen gene as an internal reference gene for polymerase chain reaction of a wide range of archival and fresh mammalian tissues.

Polymerase chain reaction (PCR) from paraffin-embedded tissues provides a powerful tool to amplify DNA from a variety of recent and archival material. Because DNA from paraffin-embedded samples is more degraded than from fresh material, the amplification of reference genes is essential to exclude false-negative results. This study describes the use of the proliferative cell nuclear antigen (PCNA) gene as a reference gene in a range of animal species and in humans. The PCNA-PCR to amplify a fragment extending from exon 5 through exon 6 and including the intervening intron 6 gave a reproducible pattern, with a 280-base pair (bp) band from canine, equine, bovine, ovine, and caprine samples showing high sequence homology. Porcine, guinea pig, tiger, and lion samples, however, gave an additional fragment of approximately 197 bp. The whole intron 6 from these fragments is missing, possibly representing a pseudogene. In feline samples only the 197-bp fragment could be detected. This study shows that the PCNA gene is highly conserved across a broad range of animal species and is well suited as an internal control for PCR analysis in veterinary medicine.     

Rapid determination of polyphenols and vitamin C in plant-derived products

Polyphenols, widely spread in our diet by the consumption of plant food products, are commonly determined using Folin-Ciocalteu reagent that interacts with other different reducing nonphenolic substances and leads to an overestimation of polyphenol content. In this paper we report an optimized Folin-Ciocalteu method to specifically determine the contents of total polyphenols and vitamin C. After the optimal conditions for the colorimetric assay were set, solid-phase extraction (Oasis HLB (hydrophilic-lipophilic balance)) was carried out to eliminate the water-soluble reducing interferences including vitamin C. Colorimetric correction was thus performed by subtracting interfering substances contained in the water washing extract from the raw extract. Moreover, vitamin C present in the water washing extract can be destroyed by heating and thus colorimetrically deduced. This procedure was set up with synthetic solutions and validated on different extracts from fruit products.     

Impact of soil stockpiling and mining rehabilitation on earthworm communities

As key ‘ecosystem engineers’, earthworms improve mineralization of organic matter, plant growth, soil quality, and are an important component of many terrestrial food webs. Under appropriate conditions, they are therefore likely to accelerate the restoration of soil ecosystem function after mining.Conserving naturally occurring populations and facilitating their recolonisation appears as the most efficient way to increase earthworms’ overall effect. The impact of mining activities and restoration measures on New Zealand endemic earthworm communities was tested. Earthworm biomass and diversity were compared in four different habitat types.Mining activities, not surprisingly, are shown here to have a detrimental impact on earthworm communities. Soil stockpiling induces anaerobic conditions at and below a depth of 1 m, where earthworms do not survive. The use of stockpiled soil for vegetation replanting therefore leads to low diversity and low abundance of earthworms. An alternative restoration technique consisting in transferring vegetation and soil units (the vegetation direct transfer) was efficient in preserving earthworm populations with earthworm biomass and diversity not significantly different from those observed in undisturbed areas. Based on these results, we recommend vegetation direct transfer (VDT) to be prioritised whenever it is logistically and economically feasible. When VDT is not applicable, low stockpiles should be prioritised as they will comprise a higher proportion of good quality soil (at the surface) and a lower proportion of anaerobic and compacted soil (below 1 m depth at the studied site).     

Extraction, detection, and quantification of flavano-ellagitannins and ethylvescalagin in a Bordeaux red wine aged in oak barrels

An extraction procedure and an analytical method have been developed to detect and quantify for the first time a series of ellagitannin derivatives formed in wine during aging in oak barrels. The method involves a preliminary purification step on XAD7 HP resin followed by a second purification step on TSK 40 HW gel. The resulting extract is analyzed for compound identification and quantitative determination by high-performance liquid chromatography-electrospray ionization-mass spectrometry in single ion recording mode. Reference compounds, which are accessible through hemisynthesis from the oak C-glycosidic ellagitannin vescalagin, were used to build calibration curves, and chlorogenic acid was selected as an internal standard. This method enabled us to estimate the content of four flavano-ellagitannins and that of another newly identified wine polyphenol, beta-1-O-ethylvescalagin, in a Bordeaux red wine aged for 18 months in oak barrels. All five ellagitannin derivatives are derived from the nucleophilic substitution reaction of vescalagin with the grape flavan-3-ols catechin and epicatechin or ethanol.     

The “soil microbial loop” is not always needed to explain protozoan stimulation of plants

Protozoa stimulate plant growth, but we do not completely understand the underlying mechanisms, and different hypotheses seek to explain this phenomenon. To test these hypotheses, we grew the grass Yorkshire fog (Holcus lanatus) in pots with soil, which contained either (1) no organisms but bacteria – or (2) bacteria and protozoa. Half of the pots received a glucose treatment so as to mimic an additional root exudation. We measured plant growth and plant nitrogen uptake, along with various microbial pools and processes that support plant growth. Protozoan presence significantly enhanced soil nitrogen mineralization, plant nitrogen uptake from organic nitrogen sources, plant nitrogen content, and plant growth. By contrast, we found no evidence that glucose addition, mimicking root exudation, increased soil nitrogen availability and plant nitrogen uptake. Moreover, although protozoan presence affected bacterial community structure, it did not affect the proportion of IAA-producing bacteria in the community or plant root morphology. These results refute the “soil microbial loop” hypotheses, which suggest that protozoan stimulation of plant growth results from complex interactions between plant roots, bacteria and protozoa. Our experiment thus favours the simple explanation that increased nitrogen availability is the key factor behind the positive protozoan effect on plant growth. To exploit natural resources in an efficient and environmentally friendly way, we need to understand in detail the functioning of ecosystems. This study stresses that to achieve this, it is still urgent, besides investigating intricate food-web and signal compound interactions, also to focus on the basic stoichiometric and energetic aspects of organisms.     

家禽腺胃炎和肌胃糜烂的研究动态

<正>1肌胃和腺胃的功能腺胃呈橄榄型,体积差异大,其主体细胞分泌胃酸,降低胃内容物的pH值,使胃蛋白酶分解蛋白质。黏膜细胞分泌黏液保护胃表面的上皮细胞不会被胃酸所侵蚀,防止食物磨擦。     

Compatibility of turkey herpesvirus-infectious bursal disease vector vaccine with Marek's disease rispens vaccine injected into day-old pullets

Mixtures of turkey herpesvirus (HVT) and Rispens poultry vaccines have been used worldwide for over 20 yr, mainly for vaccination of future layers and breeders. With increasing virulence of Marek's disease (MD) virus strains, vaccination strategies are evolving toward the use of vaccines combining HVT and Rispens. A single vaccination either in ovo or at 1 day of age with the HVT + infectious bursal disease (IBD) vector vaccine is efficient against IBD. However, with vaccination programs that include a hatchery administration of the HVT + IBD vaccine, additional protection against very virulent and very virulent-plus MD viruses is needed, especially for layers and breeders. This study looked at the combination of four commercially available Rispens vaccines with the HVT + IBD vector vaccine injected at 1 day of age. MD challenge tests that were superior to 90% in relative score in all the groups vaccinated with both vaccines showed that the mixture of HVT + IBD and Rispens vaccines had no effect on clinical protection against MD, and IBD challenge tests showed that the mixture of HVT + IBD and Rispens vaccines had no effect on clinical protection against IBD, which was equal to 100% protection in all the groups vaccinated with both vaccines.