Pathogens of bark beetles (Coleoptera: Curculionidae) in Bulgarian forests

The occurrence and prevalence of bark beetle pathogens in forest stands in Bulgaria were investigated in 944 specimens belonging to 21 bark beetle species. Protozoa, microsporidia, fungi and nematodes occurred in 19 of all investigated species. The infections were found in the gut (nematodes, gregarines, microsporidia), gonads (microsporidia) and hemolymph (nematodes) of the infected insects. Protozoan species (Gregarina typographi, Gregarina spp.) were detected in eight bark beetle species. Morphometric data about G. typographi and Gregarina spp. are presented. The prevalence of the gregarines varied between 1.4% and 64.2%. Microsporidia of the genera Nosema and Chytridiopsis were revealed in three bark beetle species. The prevalence of microsporidia ranged between 1.5% and 11.8%. This is the first report of a microsporidium in Taphrorychus villifrons and of gregarines in T. villifrons, Pityogenes bistridentatus, P. conjunctus, and Orthotomicus erosus. The fungus Beauveria bassiana was found in 3.4% of Hylurgops palliatus specimens. Nematodes (in gut and haemolymph) were revealed in 19 bark beetle species and their prevalence varied between 10% and 98.5%.     

Mass spectrometry of intact V-type ATPases reveals bound lipids and the effects of nucleotide binding

The ability of electrospray to propel large viruses into a mass spectrometer is established and is rationalized by analogy to the atmospheric transmission of the common cold. Much less clear is the fate of membrane-embedded molecular machines in the gas phase. Here we show that rotary adenosine triphosphatases (ATPases)/synthases from Thermus thermophilus and Enterococcus hirae can be maintained intact with membrane and soluble subunit interactions preserved in vacuum. Mass spectra reveal subunit stoichiometries and the identity of tightly bound lipids within the membrane rotors. Moreover, subcomplexes formed in solution and gas phases reveal the regulatory effects of nucleotide binding on both ATP hydrolysis and proton translocation. Consequently, we can link specific lipid and nucleotide binding with distinct regulatory roles.     

The dipeptidyl peptidase IV inhibitor NVP-DPP728 reduces plasma glucagon concentration in cats

Glucagon-like peptide-1 (GLP-1) analogues and inhibitors of its degrading enzyme, dipeptidyl peptidase IV (DPPIV), are interesting therapy options in human diabetics because they increase insulin secretion and reduce postprandial glucagon secretion. Given the similar pathophysiology of human type 2 and feline diabetes mellitus, this study investigated whether the DPPIV inhibitor NVP-DPP728 reduces plasma glucagon levels in cats. Intravenous glucose tolerance tests (ivGTT; 0.5 g/kg glucose after 12 h fasting) and a meal response test (test meal of 50% of average daily food intake, offered after 24 h fasting) were performed in healthy experimental cats. NVP-DPP728 (0.5–2.5 mg/kg IV or SC) significantly reduced glucagon output in all tests and increased insulin output in the ivGTT. Follow-up studies will investigate the potential usefulness as therapy in diabetic cats.     

Innovative light management to improve production sustainability,overall quality,and the phenolics composition of nectarine (Prunus persica cv. Stark Red Gold)

Summary

This research was conducted under the framework of the ISAFRUIT Project and aimed to investigate the effects of different light micro-environments on the final overall quality of nectarine fruit production. Experiments were conducted in a commercial orchard of the nectarine (Prunus persica) ‘Stark Red Gold’ during 2006 and 2007. Reflective mulches were laid down in the inter-row spaces in mid-May. Those environmental conditions affected by mulching such as temperature and reflected light were monitored until fruit harvest. Fruit production per tree was enhanced by mulch-treatment in both years, but the differences were statistically significant only in 2006, when the average fruit weight was also enhanced. Nectarines became more ripe in the 2006 season, whereas no differences in the main fruit quality indices were detected in 2007.The concentrations of phenolic compounds in ripe nectarines were positively enhanced in both years. The increase in concentration of overall phenolic compounds (in mg 100 g^?1 fresh weight) was calculated to be approx. 60% in 2006 and 2007, indicating an interesting improvement of the nutraceutical and anti-oxidant potential of nectarines. Experiments were also conducted using UV plus white light irradiation under controlled conditions. The accumulation of phenolic compounds, specifically anthocyanin concentrations, in nectarines previously screened using paper bags were determined at different times after irradiation. The results clearly indicated an inducing effect of UV plus white light irradiation on the synthesis and accumulation of anthocyanins in fruit skin. The consequences for the colour and health potential of nectarines are discussed.     

Evaluation of phenolic compounds and antioxidant activity of blueberries and modelization by artificial neural networks

ABSTRACT

The study aimed at evaluating the influence of different production conditions, conservation, and extraction procedures on the total phenolic compounds and antioxidant activity of blueberries by DPPH and ABTS methods. The production factors considered were origin, altitude of the farm location, and age of the bushes. The conservation conditions considered were freezing as opposed to the fresh product. The extraction procedures included two different solvents and two orders of extraction. The data analysis was carried out by training artificial neural networks to model the data and extract information from the model.

The results obtained revealed that the type of extract and the order of extraction influenced the concentrations of phenolic compounds as well as the antioxidant activity of the different samples studied. Also the origin of the farms from where the blueberries were harvested significantly influence those properties, showing that the blueberries from Oliveira do Hospital had less phenolic compounds and lower antioxidant activity. Also older bushes at higher altitudes seem to produce berries richer in these properties. Regarding conservation, no influence was observed for phenols but a slight influence could be detected for antioxidant activity.     

Impact of storage conditions on the apple allergen Mal?d?1

Consumption of fresh apple fruits can induce allergic reactions in humans. The apple allergen Mal?d?1 is responsible for these allergic reactions in humans in Central Europe and North America. Biosynthesis of Mal?d?1 depends on apple cultivar, and its concentration increases with time during fruit storage. However, data on the impact of different fruit storage conditions during long-term storage are scarce. Hence, the Mal?d?1 contents of eight apple cultivars were analyzed for this study during long-term storage in a cold chamber as well as under controlled atmosphere conditions (CA). After harvest, apple fruits were stored for 12, 20, 28 or 36 weeks in a cold-chamber at +?2?°C or as under controlled atmosphere conditions of 1.5?% CO₂, 1.5?% O₂ at +?2?°C. Mal?d?1 content in apple fruit of all eight cultivars examined increased during fruit storage. In most cases, differences between Mal?d?1 of apple fruits stored in the cold chamber and under CA conditions were significant, but inconsistent. In apple cv. ??Elise??, fruits stored in the cold chamber contained more Mal?d?1 compared with those stored in CA, whereas the situation reversed in other varieties like cv. ??Boskoop??. The greatest Mal?d?1 content was measured in fruits of cvs. ??Golden Delicious?? and ??Gala??, whereas the smallest Mal?d?1 level was in cvs. ??Elise?? and ??Pinova?? over the whole storage time. Overall, this experiment showed the complexity of the relationship between the Mal?d?1 content, allergenicity of apple fruits, different cultivars, storage conditions and storage time. Persons allergic to apple fruits should consume the fruits as fresh as possible or only after a limited storage time. Furthermore, they should prefer apple varieties with a low content of allergenic proteins, such as cv. ??Elise?? or cv. ??Boskoop?? as a cultivar known for its large polyphenol content.