Liquefaction of glutinous rice and aroma formation in tapé preparation by ragi

Ragi is an Indonesian inoculum to prepare a fermented food called tapé. Sweet tapé with high aroma was produced by inoculation of ragi on steamed glutinous rice and incubation at 30°C for 3 d. Microorganisms found in ragi were identified as Rhizopus sp., Saccharomycopsis sp., and Streptococcus sp. Steamed glutinous rice was liquefied and saccharified by the amylases produced by Rhizopus and aroma was formed by a mixed culture of Rhizopus and Saccharomycopsis. Liquefaction was not caused by the amylases of Saccharomycopsis even though it produced high activity of α-amylase. A higher level of aroma was formed by inoculation of Streptococcus in a mixed culture of Rhizopus and Saccharomycopsis sp.     

A β-glucosidase from <Emphasis Type="Italic">Oenococcus oeni</Emphasis> ATCC BAA-1163 with potential for aroma release in wine: cloning and expression in <Emphasis Type="Italic">E. coli</Emphasis>

Lactic acid bacteria (LAB) are responsible for olfactory changes in wine during malolactic fermentation (MLF). A side characteristic of MLF is the release of grape derived aroma compounds from their glycosylated precursors by β-glycosidase activities of these bacteria. Apart from Oenococcus oeni, which is regarded as the most promising species for MLF, glycosidic activities have also been observed in wine related members of the genera Lactobacillus and Pediococcus. Nevertheless, information on the involved enzymes including their potential use in winemaking is limited. In this study we report that β-glucosidases with similar protein sequences can be identified in the genomes of Lactobacillus brevis, O. oeni and Leuconostoc mesenteroides. TTG serves as start codon for the glucosidase gene of O. oeni. The β-glucosidase of O. oeni ATCC BAA-1163 was expressed in E. coli and partially characterized. The enzyme displayed characteristics similar to β-glucosidases isolated from L. brevis and L. mesenteroides. A pH optimum between 5.0 and 5.5, and a K _m of 0.17 mmol L⁻¹ pNP-β-d-glucopyranoside were determined. A glycosyltransferase activity was observed in the presence of ethanol. The enzyme from O. oeni was capable to hydrolyze glycosides extracted from Muskat wine. This study also contains a report on glycosidase activities of several LAB species including Oenococcus kitaharae.     

Biotechnological production of γ-decalactone,a peach like aroma,by <Emphasis Type="Italic">Yarrowia lipolytica</Emphasis>

The request for new flavourings increases every year. Consumer perception that everything natural is better is causing an increase demand for natural aroma additives. Biotechnology has become a way to get natural products. γ-Decalactone is a peach-like aroma widely used in dairy products, beverages and others food industries. In more recent years, more and more studies and industrial processes were endorsed to cost-effect this compound production. One of the best-known methods to produce γ-decalactone is from ricinoleic acid catalyzed by Yarrowia lipolytica, a generally regarded as safe status yeast. As yet, several factors affecting γ-decalactone production remain to be fully understood and optimized. In this review, we focus on the aromatic compound γ-decalactone and its production by Y. lipolytica. The metabolic pathway of lactone production and degradation are addressed. Critical analysis of novel strategies of bioprocess engineering, metabolic and genetic engineering and other strategies for the enhancement of the aroma productivity are presented.     

Green tea aroma fraction reduces β-amyloid peptide-induced toxicity in Caenorhabditis elegans transfected with human β-amyloid minigene

Green tea is a popular world-wide beverage with health benefits that include preventive effects on cancer as well as cardiovascular, liver and Alzheimer’s diseases (AD). This study will examine the preventive effects on AD of a unique aroma of Japanese green tea. First, a transgenic Caenorhabditis elegans (C. elegans) CL4176 expressing human β-amyloid peptide (Aβ) was used as a model of AD. A hexane extract of processed green tea was further fractionated into volatile and non-volatile fractions, named roasty aroma and green tea aroma fractions depending on their aroma, by microscale distillation. Both hexane extract and green tea aroma fraction were found to inhibit Aβ-induced paralysis, while only green tea aroma fraction extended lifespan in CL4176. We also found that green tea aroma fraction has antioxidant activity. This paper indicates that the green tea aroma fraction is an additional component for prevention of AD.     

Molecular pharming — VLPs made in plants

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Dynamics in the microbial cytome — single cell analytics in natural systems

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Nitrogen-Vacancy color center in diamond — emerging nanoscale applications in bioimaging and biosensing

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IF<Subscript>1</Subscript> distribution in HepG2 cells in relation to ecto–F<Subscript>0</Subscript>F<Subscript>1</Subscript>ATPsynthase and calmodulin

F₀F₁ATPsynthase is now known to be expressed as a plasma membrane receptor for several extracellular ligands. On hepatocytes, ecto–F₀F₁ATPsynthase binds apoA–I and triggers HDL endocytosis concomitant with ATP hydrolysis. Considering that inhibitor protein IF₁ was shown to regulate the hydrolytic activity of ecto–F₀F₁ATPsynthase and to interact with calmodulin (CaM) in vitro, we investigated the subcellular distributions of IF₁, calmodulin (CaM), OSCP and β subunits of F₀F₁ATPsynthase in HepG2 cells. Using immunofluorescence and Western blotting, we found that around 50% of total cellular IF₁ is localized outside mitochondria, a relevant amount of which is associated to the plasma membrane where we also found Ca²⁺–CaM, OSCP and β. Confocal microscopy showed that IF₁ colocalized with Ca²⁺–CaM on plasma membrane but not in mitochondria, suggesting that Ca²⁺–CaM may modulate the cell surface availability of IF₁ and thus its ability to inhibit ATP hydrolysis by ecto–F₀F₁ATPsynthase. These observations support a hypothesis that the IF₁–Ca²⁺–CaM complex, forming on plasma membrane, functions in the cellular regulation of HDL endocytosis by hepatocytes.     

Somewhat in control — the role of transcription in regulating microbial metabolic fluxes

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The role of CS<Subscript>2</Subscript> in CS<Subscript>2</Subscript>/NMP mixed solvent in weakening the hydrogen bond of OH–N in coal: a DFT investigation

The interaction processes of trace amounts of N-methyl-2-pyrrolidinone (NMP), CS₂/NMP (1:1 by volume) and pure NMP solvent with the hydrogen bond of OH?N in coal were constructed and simulated by density functional theory methods. The distances and bond orders between the main related atoms, and the hydrogen bond energy of OH?N were calculated. The calculated results show that pure NMP solvent does not weaken the hydrogen bond of OH?N in coal. However, trace amounts of NMP and CS₂/NMP (1:1 by volume) have a strong capacity to weaken the hydrogen bond of OH?N in coal. The H2–N3 distances are elongated from 1.87 Å to 3.80 Å and 3.44 Å, the bond orders of H2–N3 all disappear, and the corresponding hydrogen bond energies of OH?N in coal decrease from 45.72 kJ mol^?1 to 7.06 and 11.24 kJ mol^?1, respectively. These results show that CS₂ added to pure NMP solvent plays an important role in releasing the original capacity of NMP to weaken the hydrogen bond of OH?N in coal, in agreement with experimental observations.     

Spatial variation in flux, δ<Superscript>13</Superscript>C and δ<Superscript>2</Superscript>H of methane in a small Arctic lake with fringing wetland in western Greenland

Small lakes in northern latitudes represent a significant source of CH₄ to the atmosphere that is predicted to increase with warming in the Arctic. Yet, whole-lake CH₄ budgets are lacking as are measurements of δ¹³C-CH₄ and δ²H-CH₄. In this study, we quantify spatial variability of diffusive and ebullitive fluxes of CH₄ and corresponding δ¹³C-CH₄ and δ²H-CH₄ in a small, Arctic lake system with fringing wetland in southwestern Greenland during summer. Net CH₄ flux was highly variable, ranging from an average flux of 7 mg CH₄ m^?2 d^?1 in the deep-water zone to 154 mg CH₄ m^?2 d^?1 along the lake margin. Diffusive flux accounted for ~8.5 % of mean net CH₄ flux, with plant-mediated and ebullitive flux accounting for the balance of the total net flux. Methane content of emitted ebullition was low (mean ± SD 10 ± 17 %) compared to previous studies from boreal lakes and wetlands. Isotopic composition of net CH₄ emissions varied widely throughout the system, with δ¹³C-CH₄ ranging from ?66.2 to ?55.5 ‰, and δ²H-CH₄ ranging from ?345 to ?258 ‰. Carbon isotope composition of CH₄ in ebullitive flux showed wider variation compared to net flux, ranging from ?69.2 to ?49.2 ‰. Dissolved CH₄ concentrations were highest in the sediment and decreased up the water column. Higher concentrations of CH₄ in the hypoxic deep water coincided with decreasing dissolved O₂ concentrations, while methanotrophic oxidation dominated in the epilimnion based upon decreasing concentrations and increasing values of δ¹³C-CH₄ and δ²H-CH₄. The most depleted ¹³C- and ²H-isotopic values were observed in profundal bottom waters and in subsurface profundal sediments. Based upon paired δ¹³C and δ²H observations of CH₄, acetate fermentation was likely the dominant production pathway throughout the system. However, isotopic ratios of CH₄ in deeper sediments were consistent with mixing/transition between CH₄ production pathways, indicating a higher contribution of the CO₂ reduction pathway. The large spatial variability in fluxes of CH₄ and in isotopic composition of CH₄ throughout a single lake system indicates that the underlying mechanisms controlling CH₄ cycling (production, consumption and transport) are spatially heterogeneous. Net flux along the lake margin dominated whole-lake flux, suggesting the nearshore littoral area dominates CH₄ emissions in these systems. Future studies of whole-lake CH₄ budgets should consider this significant spatial heterogeneity.     

Variation in leaf and soil δ<Superscript>15</Superscript>N in diverse tree species in a lowland dipterocarp rainforest,Malaysia

Key message

Large variations in leaf δ ¹⁵ N in Bornean tropical rainforest trees may indicate that various tropical species have species-specific strategy for nitrogen uptake under low soil nutrient conditions, including root symbiotic microorganisms such as ectomycorrhiza.

Abstract

Lowland tropical rainforests in Southeast Asia are characterized by high species diversity despite limited soil nutrient conditions. The plant nitrogen isotope ratio (δ¹⁵N) reflects plant uptake of soil nitrogen. We analyzed δ¹⁵N values and nitrogen content (N %) in leaves and roots of 108 woody species with different types of symbiotic microorganisms, of different life forms (emergent, canopy, sub-canopy, understory, and canopy gap species), and from different families in a Bornean lowland dipterocarp forest to gain more insight into the diversity of nitrogen uptake strategy in the rhizosphere. Leaf δ¹⁵N values in the species studied varied largely from ?7.2 to 5.0 ‰, which is comparable to the values of known Asian trees including temperate, sub-tropical, and tropical mountain forests. Leaf δ¹⁵N also varied significantly among both life forms and families, though the phylogenetically independent contrast (PIC) relationships were not statistically significant among life form, family, and symbiotic types. Some families showed specific leaf δ¹⁵N values; Dipterocarpaceae, the dominant family in the canopy layer with symbiotic ectomycorrhiza in Southeast Asia, had small intraspecific variation and higher leaf δ¹⁵N values (0.03 ‰) compared with species exhibiting arbuscular mycorrhiza, whereas several families such as Burseraceae, Euphorbiaceae, and Myrtaceae showed large interspecific variation in leaf δ¹⁵N (e.g., from ?7.2 to 5.0 ‰ in Euphorbiaceae). These variations suggest that tropical species may have family- or species-specific strategy, such as root symbiotic microorganisms, for nitrogen uptake under low-nutrient conditions in tropical rainforests in Southeast Asia.

     

Genotype × region and genotype × production level interactions in Holstein cows

The identification of the presence of genotype by environment interaction effects on important traits in Holstein cattle allows for the use of international genetic evaluations and a more efficient design of regional genetic evaluation programmes. The aim of this study was to determine the genotype × environment interaction effects in Chilean Holstein dairy cattle through the analysis of records corresponding to calvings between 1998 and 2015. Herds were classified in the central and southern regions of Chile based on herd location as well as by high and low levels of production environments based on the fat plus protein yield averages per herd within each region. The central region has a Mediterranean climate and a confined production system while the southern region has a humid temperate climate and a production system based on grazing with supplementation. Traits studied were milk yield (MY), fat yield (FY), protein yield (PY), fat content (FC) and protein content (PC) by lactation, age at first calving (AFC) and calving interval (CI). Several four-trait mixed animal models were applied to environmental category data as different traits, which included herd-year-calving season (herd-year-birth season for AFC) and lactation number as fixed effects, and animal additive genetic, sire-herd, permanent environment and residual effects as random effects. Genetic correlations (r_g) for MY, FY, FC, PC and CI were found to decrease as differences between environmental categories increased. The r_g between the most extreme environmental categories considered in this study for AFC (0.26) was the only one found statistically lower than 0.60. Genetic correlation values statistically lower than 0.80 (P < 0.05) were observed for AFC, CI, MY, FY and PY between some environmental categories. If separate genetic evaluations are adopted as practical criteria when the value of r_g is lower than 0.60, the consequence of improving a multi-trait economic breeding objective in this population is likely to be small unless extreme environmental categories are considered. However, a moderate decrease in selection response and re-ranking of selection candidates is expected for AFC, CI and yield traits when selection is performed in different environmental conditions. Genotype × environment interaction effects involving production systems in a Mediterranean climate and confinement vs. Temperate Oceanic climate and grazing with supplementation, and between two fat plus protein yield level categories within each environment, were at most moderate for the studied traits.     

Somatic Embryogenesis and in vitro Flowering in <Emphasis Type="Italic">Saposhnikovia divaricata</Emphasis>

Efficient somatic embryogenesis (SE) and in vitro flowering and fruiting were achieved in Saposhnikovia divaricata (Turcz.) Schischk. Friable embryogenic callus developed from the root, internode, and leaf explants on Murashige and Skoog medium (MS) with 2.26 μM 2,4-dichlorophenoxyacetic acid (2,4-D), and subsequently developed into somatic embryos on MS medium containing 4–5% sucrose, 1.74 μM naphthaleneacetic acid (NAA), 4.44 μM 6-benzylaminopurine (BA), and 1.90 μM abscisic acid (ABA). Then the mature embryos were separated and transferred onto MS with 3% sucrose and 0.6% agar for further development and conversion to plantlets. In vitro flowering and fruiting were obtained when the subcultures were carried out for over 15 months. Paclobutrazol (PP333) or ethephon (ETH) at low levels promoted flowering significantly. Also, abnormal rootless somatic embryos of S. divaricata could form flowers and fruits in vitro.