Volatile compounds produced in cheese by pseudomonas strains of dairy origin belonging to six different species

Production of volatile compounds by seven Pseudomonas strains belonging to six different species, Ps. brenneri, Ps. graminis, Ps. libanensis, Ps. lundensis, Ps. putida, and Ps. rhodesiae, was investigated, with the aim of elucidating their possible contribution to the volatile profile of cheese. Laboratory-scale cheeses were made from pasteurized milk of low bacterial counts separately inoculated with approximately 10(5) colony-forming units/mL of each Pseudomonas strain and ripened for 12 days at 10 degrees C. A total of 122 volatile compounds were identified in cheeses by GC-MS of the dynamic headspace. The abundance of 62 compounds, belonging to eight chemical groups (aldehydes, ketones, acids, esters, alcohols, hydrocarbons, benzene compounds, and sulfur compounds) increased during ripening for at least one of the strains. Most groups of volatile compounds were more abundant in the outer part of cheeses than in the inner part, in agreement with the aerobic metabolism of the genus Pseudomonas and coinciding with the higher counts in the outer part. Production of volatile compounds in cheese by Pseudomonas was shown to be species-dependent.     

Evaluation of different sampling methods and results of real-time PCR for detection of feline herpes virus-1, Chlamydophila felis and Mycoplasma felis in cats

Objective To investigate how different sampling techniques affect detection of DNA from feline herpes virus Type 1 (FHV-1), Chlamydophila felis and Mycoplasma felis and to study the correlation between positive test results and clinical signs in cats. Animals Fifty-one cats; 24 with ocular signs and 27 healthy control cats. Procedures Samples were collected from all cats using cotton swabs, conjunctival and corneal biopsies, and corneal scrapings. Samples were analyzed for presence of FHV-1, C. felis, M. felis, and feline DNA, defined by 28S rDNA, by using real-time PCR. Results In affected cats, FHV-1 was detected in only one cat; C. felis and M. felis were not detected in any affected cats. None of the three organisms was detected in any control cats. Feline DNA was demonstrated in all conjunctival samples, in 82% of corneal swabs, 92% of corneal scrapings, and 100% of keratectomy samples. Conclusions Because of the generally low detection rate for FHV-1, C. felis, and M. felis DNA in this study, differences regarding sampling technique could not be determined and correlation between positive test results and degree of clinical signs could not be made. Detection of feline DNA in most samples irrespective of sampling technique, suggests a low prevalence of FHV-1, C. felis and M. felis in this population of cats.     

Chemical characterization of oak heartwood from Spanish forests of Quercus pyrenaica (Wild.). Ellagitannins, low molecular weight phenolic, and volatile compounds

The need for new sources of quality wood supply for cooperage has led to looking into the possibility of utilizing Quercus pyrenaica Wild. oak, a species native to the Iberian peninsula, as an alternative to other European (Quercus robur and Qurecus petraea) and American (Quercus alba) oaks. The low molecular weight phenolic composition, ellagitannins, and volatile compounds (including a wide range of compound families such as volatile phenols, furanic compounds, lactones, phenyl ketones, other lignin-derived compounds, and volatile compounds related to off-flavors) of green heartwood from Spanish forest regions were studied by HPLC and GC, in order to know its enological characteristics. The chemical composition of Q. pyrenaica is similar to that of other species commonly used in cooperage to make barrels, showing only quantitative differences that were more significant with respect to American than to French species. The four provenance regions studied showed similar chemical composition, with high variability among individuals, often higher than the variability among regions of provenance, but in line with that described in other European and American oak woods. Therefore, this species must be considered to be suitable for aging wine.     

Volatile compounds and sensorial characterization of wines from four Spanish denominations of origin, aged in Spanish Rebollo (Quercus pyrenaica Willd.) oak wood barrels

The evolution of almost 40 oak-related volatile compounds and the sensorial characteristics of red wines from four Spanish denominations of origin (DOs) (Bierzo, Toro, Ribera de Duero, and Rioja) during aging in barrels made of Rebollo oak wood, Quercus pyrenaica, were studied and compared to the same wines aged in American and French oak barrels. Each oak wood added unique and special characteristics to the wine, and in addition, each wine showed a different ability to extract the compounds, which result in these characteristics from the oak wood. In general, wines aged in Q. pyrenaica wood were characterized by high levels of eugenol, guaiacol, and other volatile phenols. In regards to compounds like cis-whiskylactone or maltol, the behavior of this wood is very similar to that of American oaks. When considering phenolic aldehydes and ketones, the levels of these compounds are intermediate between those of French and American woods and depend greatly on the type of wine. The type of oak, on the other hand, does not affect the chromatic characteristics of the wines. In sensory analysis, the biggest differences are found in the olfactory phase. Among the four DOs studied, wine aged in Q. pyrenaica presented the highest notes of wood, with more aromas of roasting, toasting, milky coffee, spices, or wine-wood interactions. The wines aged in barrels made of Q. pyrenaica wood were highly regarded, and preference was shown for them over those same wines when they had been aged in barrels of American or French oak.     

Encapsulation of quercetin and myricetin in cyclodextrins at acidic pH

The in vitro formation of quercetin- and myricetin-cyclodextrin inclusion complexes in acidic medium has been characterized using the enzymatic system horseradish peroxidase, which oxidizes those flavonols in the presence of H2O2. The presence of cyclodextrins (CDs) in the reaction medium inhibited flavonol oxidation due to the complexation of the flavonol in the hydrophobic cavity of CDs. This inhibitory effect depends on the complexation constant Kc between flavonol and the CD type used. The Kc for quercetin and myricetin with the different types of CD used was calculated by nonlinear regression of the inhibition curves obtained in the presence of CDs. In both cases (quercetin and myricetin), the Kc values obtained followed the order hydroxypropyl-beta-CDs > maltosyl-beta-CDs > beta-CDs, reflecting the greater affinity of modified cyclodextrins for the studied flavonols compared with their parental beta-CDs. Moreover, the complexation efficiency (CE) values for HP-beta-CDs and quercetin or myricetin were calculated (267.4 and 5.3, respectively), indicating that HP-beta-CDs are more efficient for the complexation of quercetin than myricetin in the studied conditions, despite of the K c values being very similar in both cases.     

Serum protein response and renal failure in canine Babesia annae infection

Babesia annae piroplasms have recently been recognised as a cause of infection and disease among dogs in Europe. The pathogenesis and clinical implications of this emerging disease remain poorly understood. We conducted this study to describe the electrophoretic profiles associated with the infection and to determine if B. annae associated azotaemia is caused by renal failure. We examined by microscopy 2,979 canine blood samples submitted to a diagnostic laboratory in NW Spain between September 2001 and April 2002. Small ring-shaped piroplasms were detected in blood smears of 87 samples and the identity of 58 of these presumptive cases were confirmed by PCR. This group of 58 infected dogs and a reference group of 15 healthy non-infected dogs were our study population. For all the dogs, serum protein response to -albumin, alpha-1 globulin, alpha-2 globulin, beta globulin and gamma globulin- was measured by capillary electrophoresis. The response of infected and non-infected dogs was compared and within infected dogs, the response of those with azotaemia (19) was compared with that of non-azotaemic dogs (39). Infected dogs presented a significant elevation of total proteins and all the different globulin fractions, and significantly lower levels of albumin compared to non-infected dogs. Among infected dogs, those presenting azotaemia had significantly lower concentrations of total proteins, albumin, beta and gamma globulins, and significantly higher values of alpha-2 globulin. Specific gravity was below the threshold of 1,025 for all dogs with azotaemia for which a urine sample was available (7) suggesting that azotaemia, in these dogs was of renal origin. Azotaemic dogs had higher concentrations of cholesterol and triglycerides, probably as a result of a liver compensatory response to the loss of proteins. We conclude that serum protein response in B. annae infected dogs corresponds to the pattern of a haemolytic syndrome with intense inflammatory reaction and that the azotaemia associated to the infection is very likely of renal origin.     

Ultrastructural Changes and Production of a Xanthan-Like Polysaccharide Associated with Scald of Sugarcane Leaves Caused by Xanthomonas albilineans

Leaf scald is a vascular disease of sugarcane caused by Xanthomonas albilineans. Scalded leaves show white-yellowish streaks alternating with green zones in parallel to the main veins. These zones develop large bulliform cells, probably as a consequence of the wilting process. Moreover, a gum exudate occludes phloem and bundle vessels, and partially enters mesophyll cells. Some lysigenic cavities appear near the xylem. However, the white-yellowish streaks show both phloem and xylem completely occluded by the gum and the overall mesophyll appears to be full of this bacterial secretion, as revealed by scanning electron microscopy. The gum in conducting tissues has been purified from juice obtained from scalded stalks by precipitation with isopropyl alcohol and size-exclusion chromatography. It was identified as a xanthan-like polysaccharide and found to be composed of glucose, mannose and glucuronic acid by acidic hydrolysis and capillary electrophoresis.     

Gender differences in non-specific immune response to exercise in the lactate threshold: a study in equine athletes

Gender differences have not been shown in relation to the immune system in athletic horses. The aim of the present paper was to elucidate gender differences in the non-specific immune response of the polymorphonuclear neutrophil (PMN), plasma glucose and in hormones before and after an exercise in the lactate threshold (LT). A group of 12 Anglo-Arabian horses (6 females and 6 males, 4-7 years old) was observed. A submaximal exercise test was carried out at the LT. The results showed that males had a higher PMN percentage, plasma glucose values, Adherence index (AI) and random migration than females. Also, females showed significant negative correlations between cortisol and catecholamines with PMN and glucose with phagocytosis, and positive ones between AI and catecholamines. In males, negative correlations were established between random migration and chemotaxis with cortisol, and positive ones between cortisol and phagocytosis.     

Response of young hydroponically grown tomato plants to phenolic acids

Phenolic acids—excreted both as root exudates and by microorganisms—are of interest in cultivation systems of different horticultural crops since they have been claimed to accumulate in closed hydroponic growing systems. The aim of the present investigation was to assess the phytotoxic effects when hydroponically grown tomato plants are exposed to phenolic acids in the root environment. The tomato plants were grown in static aerated culture and exposed to benzoic, caffeic, chlorogenic, ferulic, p-hydroxybenzoic, salicylic and vanillic acid at concentrations of 50, 100, 150, 200 and 400 μM in the fresh nutrient solution. The highest concentration of all tested compounds significantly reduced fresh and dry weights. Salicylic and ferulic acid affected plants already at 150 and 200 μM while effects were less pronounced for p-hydroxybenzoic and chlorogenic acid. Chlorophyll fluorescence analysis did not result in any significant difference between any of the tested acids or concentrations. No clear dose-related pattern was obtained with respect to number of leaves and plant length. Visual assessment showed that the most deleterious effects appeared on the roots, which were discoloured and/or had slimy coatings when exposed to the phenolic acids. The uptake of several mineral nutrients was influenced at the highest concentration of all studied compounds. Significantly more bacteria were enumerated in the nutrient solution treated with phenolic acids compared to the controls. Most of the phenolic acids were degraded after 2 days during the start of the trial and within 1 day at the end of the trial. Concentrations phytotoxic to small tomato plants were 1000-fold higher than the natural concentrations measured before. Instead of potentially harmful, the relevance of certain phenolic acids as antimicrobial substances should be considered.     

The effect of different extraction techniques on extraction yield, total phenolic, and anti-radical capacity of extracts from Pinus radiata Bark

The performance of four techniques, conventional maceration, Soxhlet extraction, microwave assisted extraction (MAE), and ultrasound assisted extraction (UAE), for extraction of Pinus radiata bark, in one and several stages, were evaluated. For each technique, the mass extracted (g extract/g bark), total phenols (by Folin-Cicalteau), and tannin (by precipitation) concentration and anti-radical capacity (diphenyl-picrylhydrazyl, DPPH) were quantified. In one stage, the extracted mass increased in the following order: maceration < UAE < MAE < Soxhlet (p < 0.05). The total phenols and tannin levels were also higher with the Soxhlet technique. With additional extraction stages, only the samples produced with MAE and UAE techniques improved their parameters. Additionally, MAE extracts presented a higher anti-radical capacity than does Soxhlet and Pycnogenol^® extracts. Therefore, MAE was a simple and rapid method that was useful for extraction of P. radiata bark. Scanning electron micrographs (SEM) provided evidence of the mechanical effects on cell walls, mainly evidenced by cell destruction produced by Soxhlet, MAE, and UAE on the bark. In contrast, maceration only results in slightly ruptured cell pores, which could explain its low extraction yield.