Developing lactic acid bacteria starter cultures for wholemeal rye flour bread with improved functionality, nutritional value, taste, appearance and safety

Starter cultures composed of lactic acid bacteria (LAB) were developed based on the genotypic and phenotypic characterisation of isolates belonging to dominant groups of bacteria in spontaneous rye wholemeal sourdoughs. Combinations of strains have been evaluated on an industrial scale in the sourdough fermentation process. Wholemeal rye bread was prepared using sourdoughs obtained with 3 new starter cultures, and compared to bread made using the commercial culture (LV2). All newly developed cultures used for the preparation of wholemeal rye bread allowed to obtain better quality products as compared to the LV2 based bread. The best results were obtained when the culture containing Lactiplantibacillus plantarum 2MI8 and exopolysaccharide (EPS)-producing Weissella confusa/cibaria 6PI3 strains was applied. The addition of yeast during sourdough breads production, especially the one prepared from mentioned above starter culture, significantly improved their organoleptic properties, their volume and crumb moisture was increased, and also the crumb acidity and hardness was reduced. Fermentation of rye wholemeal dough, especially without the yeast addition, resulted in a significant reduction in the content of higher inositol phosphates as compared to the applied flour, which is associated with improved bioavailability of minerals. The results of this study prove that the investigated new starter cultures can be successfully applied in wholemeal rye bread production.

Inositol Phosphates and Retroviral Assembly: A Cellular Perspective

Understanding the molecular mechanisms of retroviral assembly has been a decades-long endeavor. With the recent discovery of inositol hexakisphosphate (IP6) acting as an assembly co-factor for human immunodeficiency virus (HIV), great strides have been made in retroviral research. In this review, the enzymatic pathways to synthesize and metabolize inositol phosphates (IPs) relevant to retroviral assembly are discussed. The functions of these enzymes and IPs are outlined in the context of the cellular biology important for retroviruses. Lastly, the recent advances in understanding the role of IPs in retroviral biology are surveyed.

Development of SNP Set for the Marker-Assisted Selection of Guar (Cyamopsis tetragonoloba (L.) Taub.) Based on a Custom Reference Genome Assembly

Guar gum, a polysaccharide derived from guar seeds, is widely used in a variety of industrial applications, including oil and gas production. Although guar is mostly propagated in India, interest in guar as a new industrial legume crop is increasing worldwide, demanding the development of effective tools for marker-assisted selection. In this paper, we report a wide-ranging set of 4907 common SNPs and 327 InDels generated from RADseq genotyping data of 166 guar plants of different geographical origin. A custom guar reference genome was assembled and used for variant calling. A consensus set of variants was built using three bioinformatic pipelines for short variant discovery. The developed molecular markers were used for genome-wide association study, resulting in the discovery of six markers linked to the variation of an important agronomic trait—percentage of pods matured to the harvest date under long light day conditions. One of the associated variants was found inside the putative transcript sequence homologous to an ABC transporter in Arabidopsis, which has been shown to play an important role in D-myo-inositol phosphates metabolism. Earlier, we suggested that genes involved in myo-inositol phosphate metabolism have significant impact on the early flowering of guar plants. Hence, we believe that the developed SNP set allows for the identification of confident molecular markers of important agrobiological traits.

Effects of Nitrogen Sources in Phytase Production on Bacterial Strains Isolated from Malaysia’s Hot Spring

Efficient strategies for phytase production gained increasing importance as more applications require high amounts of phytase for the market. Four phytase-producing bacterial strains isolated from Malaysia’s hot springs were used in this study to determine the effect of nitrogen sources on phytase production. All of the strains were screened out by applying halozone method which shows all of the strains were definitely positive phytase producer. Phytase Screening Medium (PSM) with soybean extract as substrate was used as a cultivation medium. Optimised condition with 1.0 % (w/v) of glucose (as carbon source), pH 5.5 and 37°C temperature was applied. Yeast extract and peptone were used to identify optimum nitrogen source in maximum phytase production. Quantitative analysis observed were optical density, colony forming unit, pH values and phytase activity to identify the effect of nitrogen source in phytase production. The finding was bacterial strain L3 as the best producer in producing maximum phytase (0.2162 U/mL) with optimised condition using yeast extract as nitrogen source. Findings in this study proved that yeast extract act as the optimum nitrogen source which contribute to maximum phytase production as supported by previous studies. This study can provide an efficient strategy to produce maximum phytase as few studies stated that phytase is an application tool in functional food production that consists of myo-inositol phosphates that is believed to have important pharmacological effects.

Abstract for the Organic Phosphorus 2013 conference - Panama City, Panama

Organic phosphorus (Po) compounds in soil often comprise a large component of soil total P (up to 84% for pasture), and represent a potentially significant source of P for agricultural production. Information on the quantities and forms of soil Po remains relatively limited, but we do know that inositol phosphates and their numerous metal-ion derivatives often constitute the dominant form of soil total Po. In addition, other phosphate esters, such as sugar phosphates, phospholipids and nucleic acids have often been identified in smaller quantities within soils. Various soil microorganisms, such as mycorrhizal fungi and phosphate-solubilising microorganisms (PSMs), can access inositol phosphates and other Po compounds. These microorganisms play an important role in the mineralisation of soil Po and the release of inorganic phosphorus compounds to soil solution or for direct plant uptake. Our research aims to explore the extent to which the coupled microbial and enzyme system with agricultural soils might be manipulated in order to increase the value derived from soil Po compounds as part of agricultural production. Specifically, we describe research focussed on inoculation experiments in which selected fungal and bacterial strains, alongside extracellular phosphatase enzymes, are trialled for their efficacy with respect to the mineralisation and solubilisation of Po compounds within soils. For example, arbuscular mycorrhizas (AMs) belonging to the phylum Glomeromycota could be introduced to soil ecosystems in order to benefit from the symbiotic endobacteria living inside the fungus whose genes are involved in mineral P acquisition. Such AMs could be mixed with strains of some of the most beneficial PSMs for Po mineralisation, e.g. Azospirillum spp., Bacillus spp., Penicillium spp. and Rhizobium spp. In addition, bacterial strains such as Bacillus amyloliquefaciens FZB24, FZB42 and FZB45, could be inoculated in soils due to their ability to secrete extracellular phosphatase enzymes. Our research focuses on the extent to which inoculations could increase the availability of phosphorus within soils for agricultural production, focussing largely on livestock farms and associated grass quality and yields. In particular, we will examine whether inoculation of livestock slurries and manures provides a vector for indirect manipulation of soil microbial and enzyme systems within livestock farms. The ultimate aim of this approach is to reduce the reliance of agricultural production on finite inorganic phosphorus fertiliser reserves.

Stable isotope phosphate labelling of diverse metabolites is enabled by a family of 18O-phosphoramidites

Stable isotope labelling is state-of-the-art in quantitative mass spectrometry, yet often accessing the required standards is cumbersome and very expensive. As 18O can be derived from heavy water (H218O), it is comparably cheap and particularly suited for labelling of phosphorylated compounds, provided the introduction is straight-forward and phosphate neutral loss in the ion source can be avoided. Here, a unifying synthetic concept for 18O-labelled phosphates is presented, based on a family of modified 18O2‑phosphoramidite reagents. This flexible toolbox offers access to major classes of biologically highly relevant phosphorylated metabolites as their isotopologues including - but not limited to - nucleotides, inositol phosphates, -pyrophosphates, and inorganic polyphosphates. 18O-enrichment ratios >95% and good yields are obtained consistently in gram-scale reactions, while enabling late-stage labelling. We demonstrate the utility of the 18O labelled inositol phosphates and pyrophosphates by assignment of these metabolites from different biological matrices, such as mammalian cell lysates, slime mold and plant samples. We demonstrate that phosphate neutral loss is negligible in an analytical setup employing capillary electrophoresis electrospray ionization triple quadrupole mass spectrometry.

A Role for Inositol Pyrophosphates in the Metabolic Adaptations to Low Phosphate in Arabidopsis

Phosphate is a major plant macronutrient and low phosphate availability severely limits global crop productivity. In Arabidopsis, a key regulator of the transcriptional response to low phosphate, phosphate starvation response 1 (PHR1), is modulated by a class of signaling molecules called inositol pyrophosphates (PP-InsPs). Two closely related diphosphoinositol pentakisphosphate enzymes (AtVIP1 and AtVIP2) are responsible for the synthesis and turnover of InsP8, the most implicated molecule. This study is focused on characterizing Arabidopsis vip1/vip2 double mutants and their response to low phosphate. We present evidence that both local and systemic responses to phosphate limitation are dampened in the vip1/vip2 mutants as compared to wild-type plants. Specifically, we demonstrate that under Pi-limiting conditions, the vip1/vip2 mutants have shorter root hairs and lateral roots, less accumulation of anthocyanin and less accumulation of sulfolipids and galactolipids. However, phosphate starvation response (PSR) gene expression is unaffected. Interestingly, many of these phenotypes are opposite to those exhibited by other mutants with defects in the PP-InsP synthesis pathway. Our results provide insight on the nexus between inositol phosphates and pyrophosphates involved in complex regulatory mechanisms underpinning phosphate homeostasis in plants.

A Shigella type 3 effector protein co-opts host inositol pyrophosphates for activity

Shigella spp. cause diarrhea by invading human intestinal epithelial cells. Effector proteins delivered into target host cells by the Shigella type 3 secretion system modulate host signaling pathways and processes in a manner that promotes infection. The effector OspB activates mTOR, the central cellular regulator of growth and metabolism, and potentiates the inhibition of mTOR by rapamycin. The net effect of OspB on cell monolayers is cell proliferation at infectious foci. To gain insights into the mechanism by which OspB potentiates rapamycin inhibition of mTOR, we employ in silico analyses to identify putative catalytic residues of OspB and show that a conserved cysteine-histidine dyad is required for this activity of OspB. In a screen of an over-expression library in Saccharomyces cerevisiae, we identify a dependency of OspB activity on inositol pyrophosphates, a class of eukaryotic secondary messengers that are distinct from the inositol phosphates known to act as cofactors for bacterial cysteine proteases. We show that inositol pyrophosphates are required for OspB activity not only in yeast, but also in mammalian cells - the first demonstration of inositol pyrophosphates being required for virulence of a bacterial pathogen in vivo.

Bioactivity of Inositol Phosphates

Inositol phosphates (IPs) are a huge and complex family of biomolecules, important in regulating vital cellular functions, signal transduction, energy transmission, and ion channels physiology and serving as structural components of cell membranes [...]