Seasonal and wastewater stream variation of trace organic compounds in a dairy processing plant aerobic bioreactor

Bioreactors are often an integral part of dairy factory efforts to reduce the biological oxygen demand of their wastewater. In this study, infeed, mixed liquor and supernatant samples of an aerobic bioreactor used by a dairy factory in South-Eastern Australia were analyzed for nutrients and organic compounds using gas chromatography-mass spectrometry and physicochemical analyses. Despite different concentrations of organic inputs into the bioreactor, nutrients and trace organic compounds were reduced significantly (i.e. average concentration of trace organic compounds: infeed = 1681 μg/L; mixed liquor = 257 μg/L; supernatant = 23 μg/L). However, during one sampling period the bioreactor was adversely affected by the organic loading. Trace organic compounds in the samples were predominantly fatty acids associated with animal products. The analyses suggest that it is possible to trace a disruptive input (i.e. infeed with high organic carbon concentrations) into an aerobic bioreactor by measuring concentrations of fatty acids or ammonia.     

Mapping field-scale spatial patterns of size and activity of the denitrifier community

There is ample evidence that microbial processes can exhibit large variations in activity on a field scale. However, very little is known about the spatial distribution of the microbial communities mediating these processes. Here we used geostatistical modelling to explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes. We observed a non-random distribution pattern of the size of the denitrifier community estimated by quantification of the denitrification genes copy numbers with a macro-scale spatial dependence (6–16 m) and mapped the distribution of this functional guild in the field. The spatial patterns of soil properties, which were strongly affected by presence of cattle, imposed significant control on potential denitrification activity, potential N₂O production and relative abundance of some denitrification genes but not on the size of the denitrifier community. Absolute abundance of most denitrification genes was not correlated with the distribution patterns of potential denitrification activity or potential N₂O production. However, the relative abundance of bacteria possessing the nosZ gene encoding the N₂O reductase in the total bacterial community was a strong predictor of the N₂O/(N₂ + N₂O) ratio, which provides evidence for a relationship between bacterial community composition based on the relative abundance of denitrifiers in the total bacterial community and ecosystem processes. More generally, the presented geostatistical approach allows integrated mapping of microbial communities, and hence can facilitate our understanding of relationships between the ecology of microbial communities and microbial processes along environmental gradients.     

Subcellular localisation of VEGF in different pituitary cells. Changes of its expression in oestrogen induced prolactinomas

Summary Vascular endothelial growth factor (VEGF) is an important angiogenic factor in the pituitary gland. The objective of this study was to unveil the VEGF subcellular localisation in different pituitary cell types and to evaluate changes in its expression at different time intervals after oestrogen stimulation. A relevant feature demonstrated was the identification of this cytokine in the nucleus and cytoplasm of lactotrophs, somatotrophs and gonadotrophs, as well as in follicle-stellate cells of male rats. Oestrogen treatment increased the number of VEGF immunopositive cells and its expression detected differentially by western blot in both nucleus and cytoplasm of pituitary cells when compared to the control. At ultrastructural level VEGF appeared associated with nucleolus and euchromatin involving a possible internal autocrine loop. In lactotrophs, the predominant cell of the tumour, VEGF was immunodetected in RER, Golgi complex, and vesicular organelles, supporting further the association with an auto-paracrine effect exerted by VEGF. The nucleus/cytoplasm ratio of VEGF revealed a prevalent accumulation of VEGF in the cytoplasm. The presence of VEGF in the nucleus may probably be associated with a translocation to this cell compartment. This study demonstrated a cytoplasmic and nuclear immunolocalisation of VEGF in normal and tumoural adenohypophyseal cells. In the course of prolactinoma development, the oestrogen stimulated VEGF expression in tumoural cells, promoting a vascular adaptation which contributes to growth and progression of the tumour.     

Siderophore uptake in bacteria and the battle for iron with the host; a bird’s eye view

Siderophores are biosynthetically produced and secreted by many bacteria, yeasts, fungi and plants, to scavenge for ferric iron (Fe³⁺). They are selective iron-chelators that have an extremely high affinity for binding this trivalent metal ion. The ferric ion is poorly soluble but it is the form of iron that is predominantly found in oxygenated environments. Siderophore uptake in bacteria has been extensively studied and over the last decade, detailed structural information for many of the proteins that are involved in their transport has become available. Specifically, numerous crystal structures for outer membrane siderophore transporters, as well as for soluble periplasmic siderophore-binding proteins, have been reported. Moreover, unique siderophore-binding proteins have recently been serendipitously discovered in humans, and the structures of some of their siderophore-complexes have been characterized. The binding pockets for different ferric-siderophores in these proteins have been described in great molecular detail. In addition to highlighting this structural information, in this review paper we will also briefly discuss the relevant chemical properties of iron, and provide a perspective on our current understanding of the human and bacterial iron uptake pathways. Potential clinical uses of siderophores will also be discussed. The emerging overall picture is that iron metabolism plays an extremely important role during bacterial infections. Because levels of free ferric iron in biological systems are always extremely low, there is serious competition for iron and for ferric-siderophores between pathogenic bacteria and the human or animal host.     

The Significance of Genetic Polymorphisms within and between Founder Populations of Ceratitis capitata (Wied.) from Argentina

Background

The Mediterranean fruit fly Ceratitis Capitata (DIPTERA: Tephritidae) is a major agricultural pest in Argentina. One main cause for the success of non-contaminant control programs based on genetic strategies is compatibility between natural and laboratory germplasms.A comprehensive characterization of the fruit fly based on genetic studies and compatibility analysis was undertaken on two founder populations from the provinces of Buenos Aires and Mendoza, used in pioneering sterile male technique control programmes in our country. The locations are 1,000 km apart from each other.

Methodology/Principal Findings

We compared the genetic composition of both populations based on cytological, physiological and morphological characterization. Compatibility studies were performed in order to determine the presence of isolation barriers. Results indicate that the Buenos Aires germplasm described previously is partially different from that of the Mendoza population. Both laboratory colonies are a reservoir of mutational and cytological polymorphisms. Some sexual chromosome variants such as the XL and the YL resulting from attachment of a B-chromosome to the X-chromosome or Y-chromosome behave as a lethal sex-linked factor. Our results also show incompatibility between both germplasms and pre-zygotic isolation barriers between them. Our evidence is consistent with the fact that polymorphisms are responsible for the lack of compatibility.

Conclusions

The genetic control mechanism should be directly produced in the germplasm of the target population in order to favour mating conditions. This is an additional requirement for the biological as well as economic success of control programs based on genetic strategies such as the sterile insect technique. The analysis of representative samples also revealed natural auto-control mechanisms which could be used in modifying pest population dynamics.     

Reciprocal regulation of nuclear import of the yeast MutSα DNA mismatch repair proteins Msh2 and Msh6

DNA mismatch recognition is performed in eukaryotes by two heterodimers known as MutSα (Msh2/Msh6) and MutSβ (Msh2/Msh3) that must reside in the nucleus to function. Two putative Msh2 nuclear localization sequences (NLS) were characterized by fusion to green fluorescent protein (GFP) and site-directed mutagenesis in the context of Msh2. One NLS functioned in GFP targeting assays and both acted redundantly within Msh2. We examined nuclear localization of each of the MutS monomers in the presence and absence of their partners. Msh2 translocated to the nucleus in cells lacking Msh3 and Msh6; however, cells lacking Msh6 showed significantly decreased levels of nuclear Msh2. Furthermore, the overall protein levels of Msh2 were significantly diminished in the absence of Msh6, particularly if Msh2 lacked a functional NLS. Msh3 localized in the absence of Msh2, but Msh6 localization depended on Msh2 expressing functional NLSs. Overall, the nuclear levels of Msh2 and Msh6 decline when the other partner is absent. The data suggest a stabilization mechanism to prevent free monomer accumulation in the cytoplasm.     

Dysregulated lipid metabolism in hepatocellular carcinoma cancer stem cells

Molecular Biology Reports - According to the stem cell theory for cancer, hepatocellular carcinomas are sustained by a group of cancer stem cells (CSCs) which are responsible for resistance to...     

Immune failure in the absence of profound CD4+ T-lymphocyte depletion in simian immunodeficiency virus-infected rapid progressor macaques

A fraction of simian immunodeficiency virus (SIV)-infected macaques develop rapidly progressive disease in the apparent absence of detectable SIV-specific antibody responses. To characterize the immunopathogenesis of this syndrome, we studied viral load, CD4+ T-lymphocyte numbers as well as cellular and humoral immune responses to SIV and other exogenous antigens in four SIVsm-infected rhesus macaques that progressed to AIDS 9 to 16 weeks postinoculation. Each of these animals exhibited high levels of viremia but showed relatively preserved CD4 T lymphocytes in blood and lymphoid tissues at the time of death. Transient SIV-specific antibody responses and cytotoxic T-lymphocyte responses were observed at 2 to 4 weeks postinoculation. Two of the macaques that were immunized sequentially with tetanus toxoid and hepatitis A virus failed to develop antibody to either antigen. These studies show that the SIV-infected rapid progressor macaques initially mounted an appropriate but transient cellular and humoral immune response. The subsequent immune defect in these animals appeared to be global, affecting both cellular and humoral immunity to SIV as well as immune responses against unrelated antigens. The lack of CD4 depletion and loss of humoral and cellular immune responses suggest that their immune defect may be due to an early loss in T helper function.     

Induction of disease by a molecularly cloned highly pathogenic simian immunodeficiency virus/human immunodeficiency virus chimera is multigenic

One of three full-length infectious molecular clones of SHIV(DH12R), designated SHIV(DH12R-CL-7) and obtained from productively infected rhesus monkey peripheral blood mononuclear cells, directed rapid and irreversible loss of CD4+ T cells within 3 weeks of its inoculation into Indian rhesus monkeys. Induction of complete CD4+ T-cell depletion by SHIV(DH12R-CL-7) was found to be dependent on inoculum size. The acquisition of this pathogenic phenotype was accompanied by the introduction of 42 amino acid substitutions into multiple genes of parental nonpathogenic SHIV(DH12). Transfer of the entire SHIV(DH12R-CL-7) env gene into the genetic background of nonpathogenic SHIV(DH12) failed to confer the rapid CD4+ T-lymphocyte-depleting syndrome; similarly, the substitution of gag plus pol sequences from SIV(smE543) for analogous SIV(mac239) genes in SHIV(DH12R-CL-7) attenuated the pathogenic phenotype. Amino acid changes affecting multiple viral genes are necessary, but insufficient by themselves, to confer the prototypically rapid and irreversible CD4+ T-cell-depleting phenotype exhibited by molecularly cloned SHIV(DH12R-CL-7).     

The Fate of Threatened Coastal Dune Habitats in Italy under Climate Change Scenarios

Coastal dunes worldwide harbor threatened habitats characterized by high diversity in terms of plant communities. In Italy, recent assessments have highlighted the insufficient state of conservation of these habitats as defined by the EU Habitats Directive. The effects of predicted climate change could have dramatic consequences for coastal environments in the near future. An assessment of the efficacy of protection measures under climate change is thus a priority. Here, we have developed environmental envelope models for the most widespread dune habitats in Italy, following two complementary approaches: an “indirect” plant-species-based one and a simple “direct” one. We analyzed how habitats distribution will be altered under the effects of two climate change scenarios and evaluated if the current Italian network of protected areas will be effective in the future after distribution shifts. While modeling dune habitats with the “direct” approach was unsatisfactory, “indirect” models had a good predictive performance, highlighting the importance of using species’ responses to climate change for modeling these habitats. The results showed that habitats closer to the sea may even increase their geographical distribution in the near future. The transition dune habitat is projected to remain stable, although mobile and fixed dune habitats are projected to lose most of their actual geographical distribution, the latter being more sensitive to climate change effects. Gap analysis highlighted that the habitats’ distribution is currently adequately covered by protected areas, achieving the conservation target. However, according to predictions, protection level for mobile and fixed dune habitats is predicted to drop drastically under the climate change scenarios which we examined. Our results provide useful insights for setting management priorities and better addressing conservation efforts to preserve these threatened habitats in future.