The role of fruit drinks in daily diet of some Osijek inhabitants, Croatia

The aim of the study was to assess the role of fruit drinks in daily diet of Osijek inhabitants. A special questionnaire was administered to 199 patients visiting a family physician's office during December 2003. The concentration of vitamin C (L-ascorbic acid) was determined in 42 commercially available fruit drinks. Only 11% (22/199) of study subjects did not take fruit drinks. The mean concentration of vitamin C in all samples was 150.10 +/- 166.83 mg/L. The questionnaire revealed that 89% (177/199) of study subjects using fruit drinks were taking a mean of 0.4 L of fruit drink per day, yielding a mean of 60.04 mg of vitamin C, i.e. 100% of the recommended daily allowance of 60 mg. Study results indicated fruit drinks to be a significant source of vitamin C in daily diet, however, great variation in vitamin C intake according to socioeconomic status of study subjects and type of fruit drink should be noted.     

HIV-1 Diversity,Transmission Dynamics and Primary Drug Resistance in Angola

Objectives

To assess HIV-1 diversity, transmission dynamics and prevalence of transmitted drug resistance (TDR) in Angola, five years after ART scale-up.

Methods

Population sequencing of the pol gene was performed on 139 plasma samples collected in 2009 from drug-naive HIV-1 infected individuals living in Luanda. HIV-1 subtypes were determined using phylogenetic analysis. Drug resistance mutations were identified using the Calibrated Population Resistance Tool (CPR). Transmission networks were determined using phylogenetic analysis of all Angolan sequences present in the databases. Evolutionary trends were determined by comparison with a similar survey performed in 2001.

Results

47.1% of the viruses were pure subtypes (all except B), 47.1% were recombinants and 5.8% were untypable. The prevalence of subtype A decreased significantly from 2001 to 2009 (40.0% to 10.8%, P = 0.0019) while the prevalence of unique recombinant forms (URFs) increased>2-fold (40.0% to 83.1%, P<0.0001). The most frequent URFs comprised untypable sequences with subtypes H (U/H, n = 7, 10.8%), A (U/A, n = 6, 9.2%) and G (G/U, n = 4, 6.2%). Newly identified U/H recombinants formed a highly supported monophyletic cluster suggesting a local and common origin. TDR mutation K103N was found in one (0.7%) patient (1.6% in 2001). Out of the 364 sequences sampled for transmission network analysis, 130 (35.7%) were part of a transmission network. Forty eight transmission clusters were identified; the majority (56.3%) comprised sequences sampled in 2008–2010 in Luanda which is consistent with a locally fuelled epidemic. Very low genetic distance was found in 27 transmission pairs sampled in the same year, suggesting recent transmission events.

Conclusions

Transmission of drug resistant strains was still negligible in Luanda in 2009, five years after the scale-up of ART. The dominance of small and recent transmission clusters and the emergence of new URFs are consistent with a rising HIV-1 epidemics mainly driven by heterosexual transmission.     

In situ cell retention of a CHO culture by a reverse‐flow diafiltration membrane bioreactor

Heterogeneities occur in various bioreactor designs including cell retention devices. Whereas in external devices changing environmental conditions cannot be prevented, cells are retained in their optimal environment in internal devices. Conventional reverse‐flow diafiltration utilizes an internal membrane device, but pulsed feeding causes temporal heterogeneities. In this study, the influence of conventional reverse‐flow diafiltration on the yeast Hansenula polymorpha is investigated. Alternating 180 s of feeding with 360 s of non‐feeding at a dilution rate of 0.2 h^?1 results in an oscillating DOT signal with an amplitude of 60%. Thereby, induced short‐term oxygen limitations result in the formation of ethanol and a reduced product concentration of 25%. This effect is enforced at increased dilution rate. To overcome this cyclic problem, sequential operation of three membranes is introduced. Thus, quasi‐continuous feeding is achieved reducing the oscillation of the DOT signal to an amplitude of 20% and 40% for a dilution rate of 0.2 h^?1 and 0.5 h^?1, respectively. Fermentation conditions characterized by complete absence of oxygen limitation and without formation of overflow metabolites could be obtained for dilution rates from 0.1 h^?1 – 0.5 h^?1. Thus, sequential operation of three membranes minimizes oscillations in the DOT signal providing a nearly homogenous culture over time. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1348–1355, 2014     

Brucella β 1,2 Cyclic Glucan Is an Activator of Human and Mouse Dendritic Cells

Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella β 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella β 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glucans showed neither toxicity nor immunogenicity compared to LPS and triggered antigen-specific CD8⁺ T cell responses in vivo. These cyclic glucans also enhanced antigen-specific CD4⁺ and CD8⁺ T cell responses including cross-presentation by different human DC subsets. Brucella β 1,2 cyclic glucans increased the memory CD4⁺ T cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-CD40 antibody and antigens from both hepatitis C virus and Mycobacterium tuberculosis. Thus cyclic glucans represent a new class of adjuvants, which might contribute to the development of effective antimicrobial therapies.     

Cryopreservation at −20 and −70 °C of Pleurotus ostreatus on Grains

Alternative substrates for cryopreservation at −20 °C have been little explored for basidiomycetes and could bring new possibilities of lower cost cryopreservation. Nevertheless, freezing temperatures between −15 and −60 °C are very challenging because they frequently result in cryoinjuries. The objective of this study was to evaluate substrates associated to cryoprotective agents for Pleurotus ostreatus cryopreservation at −20 or −70 °C in order to develop alternative techniques for basidiomycete cryopreservation. P. ostreatus was grown on potato dextrose agar or whole grains of oat, wheat, rice or millet and transferred to cryovials with cryoprotective solution with 1 % dimethyl sulfoxide, 5 % glycerol, 10 % saccharose, 4 % glucose, 6 % polyethylene glycol-6000 or 5 % malt extract. The mycelium in the cryovials were cryopreserved at −20 or −70 °C and recovered for evaluation of the mycelial growth viability after 1 and 3 years. Both substrates and cryoprotectants affect the viability of the mycelial growth cryopreserved at −20 or −70 °C; wheat grains combined with cryoprotectants such as saccharose or glucose are effective for keeping mycelium viable after cryopreservation at −20 °C for 1 or 3 years; for cryopreservation at −70 °C after 1 or 3 years, any substrate combined with any cryoprotectant is effective for preserving the mycelium viable, except for millet grains with polyethylene glycol after 3 years; semi-permeable cryoprotective agents such as saccharose and glucose are the most effective for cryopreservation at −20 or −70 °C for at least 3 years.     

Detection of the first incidence of Akodon paranaensis naturally infected with the Jabora virus strain (Hantavirus) in Brazil

We characterised hantaviruses circulating in different Akodon rodent species collected in midwestern Santa Catarina (SC), southern Brazil, where the Jabora hantavirus (JABV) strain was first identified in Akodon montensis. Genetic and phylogenetic analyses based on a partial S segment indicated that, in SC, Akodon paranaensis and A. montensis carried the same type of hantavirus. Additionally, we conducted the first genomic characterisation of the complete S segment from the Brazilian JABV strain. This is the first report of A. paranaensis infected with the JABV.     

Properties of baked foams based on cassava starch, sugarcane bagasse fibers and montmorillonite

The objectives of this work were to develop biodegradable trays from cassava starch, sugarcane fibers and Na-montmorillonite (Na-MMT) using a baking process and to study the effects of these components on the microstructure and physicochemical and mechanical properties of the trays. All formulations resulted in well-shaped trays with densities between 0.1941 and 0.2966 g/cm³. The addition of fibers and Na-MMT resulted in less dense and less rigid trays. As observed in the water sorption isotherms, the increase in the equilibrium moisture content was more pronounced when the samples were stored at RH (relative humidity) above 75%. The foams had high water absorption capacities (>50%) when immersed in water (1 min). The studied processing conditions resulted in good nanoclay dispersion, leading to the formation of an exfoliated structure. The trays developed in this study represent an alternative for the packaging of foods with low water contents.     

Posttranslational Modification of 6-Phosphofructo-1-Kinase in Aspergillus niger

Two different enzymes exhibiting 6-phosphofructo-1-kinase (PFK1) activity were isolated from the mycelium of Aspergillus niger: the native enzyme with a molecular mass of 85 kDa, which corresponded to the calculated molecular mass of the deduced amino acid sequence of the A. niger pfkA gene, and a shorter protein of approximately 49 kDa. A fragment of identical size also was obtained in vitro by the proteolytic digestion of the partially purified native PFK1 with proteinase K. When PFK1 activity was measured during the proteolytic degradation of the native protein, it was found to be lost after 1 h of incubation, but it was reestablished after induction of phosphorylation by adding the catalytic subunit of cyclic AMP-dependent protein kinase to the system. By determining kinetic parameters, different ratios of activities measured at ATP concentrations of 0.1 and 1 mM were detected with fragmented PFK1, as with the native enzyme. Fructose-2,6-biphosphate significantly increased the V_max of the fragmented protein, while it had virtually no effect on the native protein. The native enzyme could be purified only from the early stages of growth on a minimal medium, while the 49-kDa fragment appeared later and was activated at the time of a sudden change in the growth rate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of sequential purifications of PFK1 enzymes by affinity chromatography during the early stages of the fungal development suggested spontaneous posttranslational modification of the native PFK1 in A. niger cells, while from the kinetic parameters determined for both isolated forms it could be concluded that the fragmented enzyme might be more efficient under physiological conditions.     

Lipid-specific binding of the calcium-dependent antibiotic daptomycin leads to changes in lipid polymorphism of model membranes

Daptomycin is a cyclic anionic lipopeptide with an antibiotic activity that is completely dependent on the presence of calcium (as Ca2+). In a previous study [Jung et al., 2004. Chem. Biol. 11, 949-957], it was concluded that daptomycin underwent two Ca2+-dependent structural transitions, whereby the first transition was solely dependent on Ca2+, while the second transition was dependent on both Ca2+ and the presence of negatively charged lipids that allowed daptomycin to insert into and perturb bilayer membranes with acidic character. Differences in the interaction of daptomycin with acidic and neutral membranes were further investigated by spectroscopic means. The lack of quenching of intrinsic fluorescence by the water-soluble quencher, KI, confirmed the insertion of the daptomycin Trp residue into the membrane bilayer, while the kynurenine residue was inaccessible even in an aqueous environment. Differential scanning calorimetry (DSC) indicated that the binding of daptomycin to neutral bilayers occurred through a combination of electrostatic and hydrophobic interactions, while the binding of daptomycin to bilayers containing acidic lipids primarily involved electrostatic interactions. The binding of daptomycin to acidic membranes led to the induction of non-lamellar lipid phases and membrane fusion.