<Emphasis Type="Italic">Rubellimicrobium roseum</Emphasis> sp. nov., a Gram-negative bacterium isolated from the forest soil sample

A novel pink-coloured, non-spore-forming, non-motile, Gram-negative bacterium, designated YIM 48858^T, is described by using a polyphasic approach. The strain can grow at pH 6.5–9 (optimum at pH 7) and 25–30°C (optimum at 28°C). NaCl is not required for its growth. Positive for oxidase and catalase. Urease activity, nitrate reduction, starch and Tween 80 tests are negative reaction. 16S rRNA gene sequence similarity studies showed that strain YIM 48858^T is a member of the genus Rubellimicrobium, with similarities of 96.3, 95.7 and 95.5% to Rubellimicrobium mesophilum MSL-20^T, Rubellimicrobium aerolatum 5715S-9^T and Rubellimicrobium thermophilum DSM 16684^T, respectively. Q-10 was the predominant respiratory ubiquinone as in the other members of the genus Rubellimicrobium. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphoglycolipid, glycolipid and the major fatty acids were C18:1 ω7c, C16:0 and C10:0 3-OH, which are very different from the valid published species. The DNA G + C content was 67.7 mol%. Both phylogenetic and chemotaxonomic evidence supports that YIM 48858^T is a novel species of the genus Rubellimicrobium, for which the name Rubellimicrobium roseum sp. nov. is proposed. The type strain is YIM 48858^T (=CCTCC AA 208029^T =KCTC 23202^T).     

Behavioural phenotype affects social interactions in an animal network

Animal social networks can be extremely complex and are characterized by highly non-random interactions between group members. However, very little is known about the underlying factors affecting interaction preferences, and hence network structure. One possibility is that behavioural differences between individuals, such as how bold or shy they are, can affect the frequency and distribution of their interactions within a network. We tested this using individually marked three-spined sticklebacks (Gasterosteus aculeatus), and found that bold individuals had fewer overall interactions than shy fish, but tended to distribute their interactions more evenly across all group members. Shy fish, on the other hand, tended to associate preferentially with a small number of other group members, leading to a highly skewed distribution of interactions. This was mediated by the reduced tendency of shy fish to move to a new location within the tank when they were interacting with another individual; bold fish showed no such tendency and were equally likely to move irrespective of whether they were interacting or not. The results show that animal social network structure can be affected by the behavioural composition of group members and have important implications for understanding the spread of information and disease in social groups.     

Functional expression of human pyruvate carboxylase for reduced lactic acid formation of Chinese hamster ovary cells (DG44)

To investigate the effect of human pyruvate carboxylase (hPC) on lactate formation in Chinese hamster ovary (CHO) cell lines, FLAG-tagged hPC was introduced into a dihydrofolate-deficient CHO cell line (DG44). Three clones expressing high levels of hPC, determined by Western blotting using an anti-FLAG monoclonal antibody, and a control cell line were established. Immunocytochemistry revealed that a substantial amount of expressed hPC protein was localized in the mitochondria of the cells. hPC expression did not impair cell proliferation. Rather, it improved cell viability at the end of adherent batch cultures with the serum-containing medium probably because of reduced lactate formation. Compared with control cells, specific lactate production rate of the three clones was decreased by 21–39%, which was because of a decreased specific glucose uptake rate and yield of lactate from glucose. Reduced lactate formation by hPC expression was also observed in suspension fed-batch cultures using a serum-free medium. Taken together, these results demonstrate that through the expression of the hPC enzyme, lactate formation in CHO cell culture can be efficiently reduced.     

Characteristics of Environmental <Emphasis Type="Italic">Paracoccidioides brasiliensis</Emphasis> Isolates

The ecological niche or exact habitat of the fungus Paracoccidioides brasiliensis is not known, and few isolates have been obtained from the environment. In this study, ten isolates were analyzed with respect to antigenic composition, serology, pathogenicity, and molecular aspects. Gp43 is considered to be the molecular basis for the serodiagnosis of paracoccidioidomycosis; however, in this study only six of the environmental isolates secreted this molecule (four in great amounts and two in small amounts). Other molecules were also produced. When exoantigens from these isolates were tested using immunodiffusion, only four preparations were positive by ID tests. However, when these exoantigens were tested by ELISA, all of them except one were able to detect anti-P. brasiliensis antibodies. In Western blot assays, these exoantigens showed different reactivities. Isolates that secreted gp43 presented positive reactions for this molecule, and isolates that did not secrete gp43 gave positive reactions for other minor molecules. RAPD analysis revealed that there is great genetic variation between these environmental isolates. These isolates were non-pathogenic: no mortality was observed among the inoculated mice during an 18-month follow-up period.     

Biogenic and Risk Elements in Wines from the Slovak Market with the Estimation of Consumer Exposure

Wine consumption delivers macroelements and microelements necessary for the proper metabolism. On the other hand, wine can be an important source of toxic metals. The aim of this study was to estimate the concentrations of Ca, Cd, Cu, Fe, Hg, Mg, Ni, Pb, and Zn in the Slovak and non-Slovak wines. The concentration of metals was evaluated with respect to the type, the alcohol content, and the age of Slovak wine. The general scheme of concentrations found was as follows Ca > Mg > Fe > Zn > Pb > Cd > Ni > Cu > Hg. The type of wine and the alcohol content do not have a significant impact on metal concentrations. Also, the age of wine has no influence on the mean concentration of metals, except for Zn. Metal concentrations in Slovak and non-Slovak wines indicate similar contents of metals, except for Ni. The contribution to both dietary reference values (DRVs) and provisional tolerable weekly intake (PTWI) evaluations in the Slovak wine suggested low dietary exposure to Ca, Cu, Fe, Mg, Ni, Zn, Cd, Hg, and Pb, respectively. However, we do not suggest that the consumption of all Slovak wines is healthy. The maximum Pb concentrations in Slovak wines exceed the maximum permitted level proposed by the European Commission. This might be proved by the results of the margin of the exposure (MOE) value evaluation in the samples containing the maximum Pb concentrations, showing a high risk of CKD and SBP in high and extreme consumption groups.     

Influence of Surfactants on Lipase Fat Digestion in a Model Gastro-intestinal System

In the present study, we use a model gastro-intestinal system to study the influence of different food-grade surface-active molecules (Sn-2 monopalmitin, β-lactoglobulin, or lysophosphatodylcholine) on lipase activity. The interfacial activity of lipase and surfactants are assessed with the pendant drop technique, a commonly used tensiometry instrument. A mathematical model is adopted which enables quantitative determination of the composition of the water–oil interface as a function of bulk surfactant concentration in the water–oil mixtures. Our results show a decrease in gastric lipolysis when interfacially active molecules are incorporated into a food matrix. However, only the Sn-2 monopalmitin caused a systematic decrease in triglyceride hydrolysis throughout the gastro-intestinal tract. This effect is most likely due to exclusion of both lipase and triglyceride from the water–oil interface together with a probable saturation of the solubilization capacity of bile with monoglycerides. Addition of β-lactoglobulin or lysophopholipids increased the hydrolysis of fat after the gastric phase. These results can be attributed to an increasing interfacial area with lipase and substrate present at the interface. Otherwise, β-lactoglobulin, or lysophopholipids reduced fat hydrolysis in the stomach. From the mathematical modeling of the interface composition, we can conclude that Sn-2 monopalmitin can desorb lipase from the interface, which, together with exclusion of substrate from the interface, explains the gradually decreased triglyceride hydrolysis that occurs during the digestion. Our results provide a biophysics approach on lipolysis that can bring new insights into the problem of fat uptake.     

The Interactions of Glutathione-Capped CdTe Quantum Dots with Trypsin

Due to their unique fluorescent properties, quantum dots present a great potential for biolabelling applications; however, the toxic interactions of quantum dots with biopolymers are little known. The toxic interactions of glutathione-capped CdTe quantum dots with trypsin were studied in this paper using synchronous fluorescence spectroscopy, fluorescence emission spectra, and UV–vis absorption spectra. The interaction between CdTe quantum dots and trypsin resulted in structure changes of trypsin and inhibited trypsin's activity. Fluorescence emission spectra revealed that the quenching mechanism of trypsin by CdTe quantum dots was a static quenching process. The binding constant and the number of binding sites at 288 and 298 K were calculated to be 1.98 × 10⁶ L mol⁻¹ and 1.37, and 6.43 × 10⁴ L mol⁻¹ and 1.09, respectively. Hydrogen bonds and van der Waals' forces played major roles in this process.     

Familiar soil conditions help Pinus ponderosa seedlings cope with warming and drying climate

Changes in temperature and moisture as a result of climate forcing can impact performance of planted trees. Tree performance may also be sensitive to new soil conditions, for example, brought about by seeds germinating in soils different from those colonized by ancestral populations. Such “edaphic constraint” may occur with natural migration or human‐assisted movement. Pinus ponderosa seedlings, sourced from one location (“home” site), were grown across a field environmental gradient in either their original home soil or in soils from two different “away” sites. Seedlings were inoculated with site‐specific soil organisms by germinating seeds in living soil. After 6 months, the inoculated seedlings were transplanted into sterilized soils from the home or away sites. This experimental design allowed us to uncouple the importance of abiotic and biotic soil properties and test (1) how biotic and abiotic soil properties interact with climate to influence plant growth and stress tolerance, and (2) the role of soil biota in facilitating growth in novel environments. Seedlings grew least in hotter and drier away sites with away soil biota. Home soil biota ameliorated negative impacts on growth of hotter and drier away sites. Measurements of photosynthetic rate, stomatal conductance, and chlorophyll florescence (Fv/Fm) suggest that edaphic constraint reduced growth by increasing tree water stress. Results suggest that success of Ponderosa pine plantings into warming environments will be enhanced by pre‐inoculation with native soil biota of the seed source.     

Mitochondrial dysfunction in platelets and hippocampi of senescence-accelerated mice

Senescence-accelerated mice (SAM) strains are useful models to understand the mechanisms of age-dependent degeneration. In this study, measurements of the mitochondrial membrane potential (Δψ_m) of platelets and the Adenosine 5^′-triphosphate (ATP) content of hippocampi and platelets were made, and platelet mitochondria were observed in SAMP8 (faster aging mice) and SAMR1 (aging resistant control mice) at 2, 6 and 9 months of age. In addition, an Aβ-induced (Amyloid beta-protein) damage model of platelets was established. After the addition of Aβ, the Δψ_m of platelets of SAMP8 at 1and 6 months of age were measured. We found that platelet Δψ_m, and hippocampal and platelet ATP content of SAMP8 mice decreased at a relatively early age compared with SAMR1. The platelets of 6 month-old SAMP8 showed a tolerance to Aβ-induced damages. These results suggest that mitochondrial dysfunction might be one of the mechanisms leading to age-associated degeneration in SAMP mice at an early age and the platelets could serve as a biomarker for detection of mitochondrial function and age related disease.