The time response of anaerobic digestion microbiome during an organic loading rate shock

Knowledge of connections between operational conditions, process stability, and microbial community dynamics is essential to enhance anaerobic digestion (AD) process efficiency and management. In this study, the detailed temporal effects of a sudden glycerol-based organic overloading on the AD microbial community and process imbalance were investigated in two replicate anaerobic digesters by a time-intensive sampling scheme. The microbial community time response to the overloading event was shorter than the shifts of reactor performance parameters. An increase in bacterial community dynamics and in the abundances of several microbial taxa, mainly within the Firmicutes, Tenericutes, and Chloroflexi phyla and Methanoculleus genera, could be detected prior to any shift on the reactor operational parameters. Reactor acidification already started within the first 24 h of the shock and headed the AD process to total inhibition in 72 h alongside with the largest shifts on microbiome, mostly the increase of Anaerosinus sp. and hydrogenotrophic methanogenic Archaea. In sum, this work proved that AD microbial community reacts very quickly to an organic overloading and some shifts occur prior to alterations on the performance parameters. The latter is very interesting as it can be used to improve AD process management protocols.

     

Ammonia beccarii and Ammonia tepida (Foraminifera): morphofunctional arguments for their distinction

New observations from Yeu Island and the Bay of Bourgneuf on the Atlantic coast of France show that Ammonia beccarii s.s. and Ammonia tepida have different morphofunctional adaptations to their habitats and environments. Adult A. beccarii s.s. may be epiphytic, living on the calcareous alga Corallina officinalis or on the red alga Gigartina acicularis along rocky shores, while A. tepida is endopelic, living in sediments of brackish environments. Rapid 3-D emission of pseudopodia from interlocular spaces on both umbilical and spiral sides of adult A. beccarii s.s. can support its test within the seaweed framework. This behaviour is characteristic of phytal species. Thus, it appears that the major difference between A. beccarii s.s. and A. tepida is the presence of large interlocular spaces on spiral side of the former, corresponding to a potential morphofunctional adaptation to the epiphytic mode of life. We believe that these observations could help to solve the long-lasting A. beccarii problems of specific distinction.     

Epithelial organization: may the force be with you

Multicellular organization is determined by the balance of forces between cells as much as by the expression of genes. A recent study in Drosophila combines physical modeling with experimental measurements and mechanical perturbations to shed light on the processes that influence cell patterns in vivo.     

Divergent Cardiopulmonary Actions of Heme Oxygenase Enzymatic Products in Chronic Hypoxia

Background

Hypoxia and pressure-overload induce heme oxygenase-1 (HO-1) in cardiomyocytes and vascular smooth muscle cells (VSMCs). HO-1^−/− mice exposed to chronic hypoxia develop pulmonary arterial hypertension (PAH) with exaggerated right ventricular (RV) injury consisting of dilation, fibrosis, and mural thrombi. Our objective was to indentify the HO-1 product(s) mediating RV protection from hypoxic injury in HO-1^−/− mice.

Methodology/Principal Findings

HO-1^−/− mice were exposed to seven weeks of hypoxia and treated with inhaled CO or biliverdin injections. CO reduced right ventricular systolic pressure (RVSP) and prevented hypoxic pulmonary arteriolar remodeling in both HO-1^−/− and control mice. Biliverdin had no significant effect on arteriolar remodeling or RVSP in either genotype. Despite this, biliverdin prevented RV failure in the hypoxic HO-1^−/− mice (0/14 manifested RV wall fibrosis or thrombus), while CO-treated HO-1^−/− mice developed RV insults similar to untreated controls. In vitro, CO inhibited hypoxic VSMC proliferation and migration but did not prevent cardiomyocyte death from anoxia-reoxygenation (A-R). In contrast, bilirubin limited A-R-induced cardiomyocyte death but did not inhibit VSMC proliferation and migration.

Conclusions/Significance

CO and bilirubin have distinct protective actions in the heart and pulmonary vasculature during chronic hypoxia. Moreover, reducing pulmonary vascular resistance may not prevent RV injury in hypoxia-induced PAH; supporting RV adaptation to hypoxia and preventing RV failure must be a therapeutic goal.     

Non-invasive assessment of embryonic sex in cattle by metabolic fingerprinting of in vitro culture medium

The objective of this work was to determine whether metabolic fingerprinting of spent bovine embryo culture media using Fourier transform infrared spectroscopy (FTIR) correlates with embryonic sex. Embryos were produced in vitro from oocytes collected from cows slaughtered in an abattoir. Day-6 embryos were individually cultured in synthetic oviduct fluid for 24 h, prior to the time (Day-7) intended for embryo transfer or cryopreservation. Culture medium was analyzed by FTIR. Embryos were sexed by a PCR procedure based on amelogenin gene amplification or transferred to a recipient and sex observed at birth. Media samples from embryos diagnosed as male (n = 47) or female (n = 70) were individually collected and evaluated using FTIR. The spectra obtained were analyzed according to metabolomic profile of embryo culture media and embryonic sex. The discrimination capability of the classifiers was assessed for accuracy, sensitivity (female), sensitivity (male) and area under the ROC curve (AUC). Performance of sex prediction (%) was high within early blastocysts + blastocysts (74.4 ± 10.2, accuracy; 0.749 ± 0.099, AUC) and excellent for expanded blastocysts (86.0 ± 12.6, accuracy; 0.898 ± 0.094, AUC). A combination of metabolomic and bioinformatic analysis provides a non-invasive mean of embryonic sex analysis.     

Treatment with cholesterol-loaded methyl-β-cyclodextrin increased the cholesterol in rabbit oocytes,but did not improve developmental competence of cryopreserved oocytes

Membrane cholesterol:phospholipids ratio is an important determinant of cell chilling sensitivity. At low temperatures, major membrane destabilisation occurs when the membrane undergoes a phase transition. To increase membrane fluidity and stability during cooling and thus increase oocyte cryoresistance, cholesterol has been added to the plasma membrane. This study was conducted to determine if cholesterol could be incorporated into rabbit oocytes by incubation with cholesterol-loaded methyl-β-cyclodextrin (CLC) and if added cholesterol could improve the developmental ability of cryopreserved oocytes after parthenogenetic activation or intracytoplasmic sperm injection. Fresh, frozen and vitrified oocytes incubated with CLC containing 20% NBD-labelled cholesterol (NBD-CLC) were evaluated using confocal microscopy. Fluorescence intensity was higher in fresh oocytes than in cryopreserved ones. Pre-treating rabbit oocytes with 1 mg of NBD-CLC/mL did not improve cleavage and developmental rates after cryopreservation. Results showed that treatment with CLC increased the cytoplasmic cholesterol content, but did not improve cleavage rate and developmental competence of cryopreserved oocytes.     

First occurrence of Caprella scaura Templeton, 1836 (Crustacea: Amphipoda) on off-coast fish farm cages in the Mediterranean Sea

The non-indigenous caprellid Caprella scaura Templeton, 1836, native to the western Indian Ocean, was firstly recorded in the Mediterranean Sea in 1994, and all Mediterranean populations discovered to date are related to shoreline areas. A total of ten fish farms were sampled off the coasts of Spain (4), Italy (1), Croatia (2), Greece (1) and Malta (2). This is the first time that C. scaura has been reported from off-coast areas. Reproducing populations have been detected in fouling communities of three tuna farms off the coast of Croatia and Malta, which also signifies the first confirmed record of this species in both countries. The occurrence of successfully established and thriving populations of C. scaura Templeton, 1836 at floating off-coast fish farms underlines the importance of these structures as stepping stones in the species.     

Powering morphogenesis: multiscale challenges at the interface of cell adhesion and the cytoskeleton

Among the defining features of the animal kingdom is the ability of cells to change shape and move. This underlies embryonic and postembryonic development, tissue homeostasis, regeneration, and wound healing. Cell shape change and motility require linkage of the cell’s force-generating machinery to the plasma membrane at cell–cell and cell–extracellular matrix junctions. Connections of the actomyosin cytoskeleton to cell–cell adherens junctions need to be both resilient and dynamic, preventing tissue disruption during the dramatic events of embryonic morphogenesis. In the past decade, new insights radically altered the earlier simple paradigm that suggested simple linear linkage via the cadherin–catenin complex as the molecular mechanism of junction–cytoskeleton interaction. In this Perspective we provide a brief overview of our current state of knowledge and then focus on selected examples highlighting what we view as the major unanswered questions in our field and the approaches that offer exciting new insights at multiple scales from atomic structure to tissue mechanics.     

Characterization of a region of plasmid pBL1 of Brevibacterium lactofermentum involved in replication via the rolling circle model.

The minimal region for autonomous replication of pBL1, a 4.5-kb cryptic plasmid of Brevibacterium lactofermentum ATCC 13869 that has been used to construct a variety of corynebacterium vectors, was shown to be contained on a 1.8-kb HindII-SphI DNA fragment. This region contains two open reading frames (ORFs) (ORF1 and ORF5) which are essential for pBL1 replication in B. lactofermentum. Accumulation of single-strand intermediates in some of the constructions indicates that plasmid pBL1 replicates via the rolling circle replication model; its plus strand and minus strand were identified by hybridization with two synthetic oligonucleotide probes complementary to each pBL1 strand. ORF1 seems to encode the Rep protein and showed partial homology with sequences for Rep proteins from Streptomyces plasmids which replicate via rolling circle replication such as pIJ101, pSB24, and pJV1.     

Male mice produced by in vitro culture have reduced fertility and transmit organomegaly and glucose intolerance to their male offspring

It has been reported that suboptimal in vitro culture (IVC) of mouse embryos can affect the postnatal expression of epigenetically sensitive alleles, resulting in altered postnatal growth, organ dimensions, health, and behavior in the offspring. Although these detrimental impacts on the offspring are well described, the relative contribution of the IVC-produced fathers is unclear. In this work, we have analyzed if suboptimal IVC (achieved by altering the culture medium by the addition of FCS) can affect male fertility and if organ size and glucose clearance, two of the adverse effects produced by suboptimal IVC conditions, were transmitted to the next two generations. IVC-produced males had lower sperm concentrations (5.8 × 10(6) spermatozoa in IVC vs. 14.5 × 10(6) spermatozoa in control), and these sperm exhibited decreased overall motility (49.6% vs. 72.8% in control) and progressive motility (22.6% vs. 32.2% in control). Fertility tests demonstrated that the percentage of pregnancies was reduced for IVC males (35% for IVC-produced males vs. 86% for in vivo controls). These features were related to a modified gene expression pattern in adult male testes, showing an altered gene expression in genes involved in DNA repair and apoptosis that was confirmed by TUNEL assay. Regarding the IVC related adverse phenotype transmitted to offspring, male glucose intolerance was shown only in F1 and F2 male but not female offspring. The same occurred with male abnormalities in the organ size of the liver, which were transmitted to F1 and F2 males but not to F1 females; moreover, analysis of the F0, F1, and F2 males revealed greater coefficients of variance in body weight and glucose intolerance than the control group. Finally, we analyzed, through gene silencing, the effect of IVC on the mRNA expression at the blastocyst stage for 11 known gene expression modifiers of epigenetic reprogramming. Suboptimal IVC reduced the expression of Kap1, Sox2, Hdac1, Dnmt1, and Dnmt3a, suggesting a molecular epigenetic role for gene expression modifiers in the origin and transmission of these abnormal phenotypes.