alpha-Ketoglutarate (AKG) absorption from pig intestine and plasma pharmacokinetics

To study the absorption, metabolism and kinetics, the AKG (in different concentrations) was administered intravenously, intra-portally, orally and directly into the ileum or duodenum of pigs, chronically fitted with portal and jugular catheters and T-shaped cannula at the duodenum and ileum. Additionally, this study was conducted to determine the influence of low pH, Fe(2+) or/and SO on AKG gut absorption and conversely FeSO(4) and FeSO(4)/AKG on Fe(2+) gut absorption. It is concluded that AKG was significantly better absorbed from the upper small intestine than from the distal sections. Furthermore, low pH, Fe(2+) and/or SO ions enhanced AKG absorption. The AKG administered to the portal vein was rapidly eliminated from the blood (half-life less than 5 min). The short lifetime for AKG is probably dependent on quick metabolism in the enteorcyetes and liver. However, the prolonged half-life can be related to its low AKG blood concentration. The Fe(2+) concentrations in blood increased after FeSO(4) and FeSO(4)/AKG duodenal infusion. The implication of above observations is important for practical application of the AKG in animal and human nutrition as well in medicine.     

Functional divergence of former alleles in an ancient asexual invertebrate

Theory suggests it should be difficult for asexual organisms to adapt to a changing environment because genetic diversity can only arise from mutations accumulating within direct antecedents and not through sexual exchange. In an asexual microinvertebrate, the bdelloid rotifer, we have observed a mechanism by which such organisms could acquire the diversity needed for adaptation. Gene copies most likely representing former alleles have diverged in function so that the proteins they encode play complementary roles in survival of dry conditions. One protein prevents desiccation-sensitive enzymes from aggregating during drying, whereas its counterpart does not have this activity, but is able to associate with phospholipid bilayers and is potentially involved in maintenance of membrane integrity. The functional divergence of former alleles observed here suggests that adoption of asexual reproduction could itself be an evolutionary mechanism for the generation of diversity.     

Susceptibility of humic acids from soils with various contents of metals to microbial utilization and transformation

Humic acids (HAs) from a pseudogley soil with various metal contents were added as supplemental sources of nutrients, or as the sole sources of carbon or nitrogen, to aerobic cultures of complex microbial populations indigenous to the same individual soils. Depending on nutrient conditions in the individual cultures and origin of HAs, between 44% and 67% of the added HAs were utilized. The lowest utilization rate was obtained for HAs from soil heavily contaminated with Mg. The overall carbon mineralization in the microbial cultures was significantly reduced in the presence of HAs. Simultaneously, the formation of microbial biomass was enhanced up to 261%. Variovorax (Alcaligenes) paradoxus, Pseudomonas fluorescens, and a yeast Cryptococcus sp. have been identified as the dominant microbial species utilizing HAs. The individual HA preparations re-isolated from the microbial cultures exhibited distinct changes in elemental and structural characteristics. Diminished contents of ash and alterations in infra-red absorptions indicated a splitting of organic and mineral components in HAs exposed to microbial activities.     

Role of IFN-α during the acute stage of a swine influenza virus infection

Cytokines, especially interferon-alpha (IFN-α) are important in controlling influenza virus infections. To investigate the role of IFN-α in influenza, the swine IFN-α neutralizing monoclonal antibody (Ab) K9 was applied in a swine model of influenza A virus infection. First, the optimal dose and route for administration of the IFN-α neutralizing Abs was determined. Based on those results, the effect of the Abs on a swine influenza virus infection was investigated. Pigs were inoculated intratracheally with 10^6.0 mean egg infectious dose (EID₅₀) A/Swine/Belgium/1/98 (H1N1) virus. At the time of challenge and 18 h later, they were injected intratracheally and intraperitoneally with a high dose of IFN-α neutralizing Abs or control Abs. The animals were euthanized at 0, 24, 30, 48 and 72 h after inoculation. At 24 and 30 h, IFN-α levels in broncho-alveolar lavage fluid of K9 recipient animals were strongly suppressed, and this coincided with reduced IL-6 and IL-12 levels. TNF-α and IL-1 levels were unaffected compared to those in the control Ab treated group. Importantly, the onset and peak of clinical symptoms in IFN-α neutralizing Abs treated animals were delayed by 24 h, simultaneously with the suppression of IFN-α, but there was no obvious effect on virus replication and lung pathology. These results suggest an important role for IFN-α in IL-6 and IL-12 induction and a role of all three cytokines in the symptoms of swine influenza.     

The impact of climate change on the yield and quality of Saaz hops in the Czech Republic

The impact of climate change on the production and quality of hops Humulus lupulus will depend on future weather conditions in the growing season. Our simulations suggest that hops will be particularly vulnerable to a change in climate. Even with the modest warming so far experienced yields have stagnated and quality declined. Recorded observations show an increase in air temperature which is associated with an earlier onset of hop phenological phases and a shortening of the vegetation period. Simulations using future climate predict a decline in both yields, of up to 7–10%, and α-acid content, of up to 13–32%, the latter a major determinant of quality. The concentration of hop cultivation in a comparatively small region in the Czech Republic makes it more vulnerable than if the crop were grown in more areas with different climates. Thus climate change may gradually lead to changes in the regionalization of hop production. Policy assistance may be necessary for the adaptation of the Czech hop growing industry to changed climatic conditions.     

Plasmid transfer between introduced and indigenous bacteria in leaf litter, soil and vermicompost as affected by soil invertebrates

 Plasmid transfer between introduced strains of Pseudomonas stutzeri JM302 (pLV1013), Pseudomonas putida PAW340 (pLV1017), Pseudomonas aeruginosa PAO5 (RP4), and Enterobacter cloacae MF10 (RP4), all of them harbouring genetically modified or naturally occurring plasmids and bacteria indigenous to oak leaf litter, soddy-podzolic soil or vermicompost was monitored using non-sterile laboratory microcosms inhabited by the millipede Pachyiulus flavipes, the woodlouse Armadillidium vulgare, or the earthworms Aporrectodea caliginosa and Eisenia fetida, respectively. Plasmid transfer from genetically modified Streptococcus faecalis JH2-2 (pAMβ₁) to Bacillus thuringiensis var. israelensis 1-5 under similar conditions was also followed. A recombinant conjugative plasmid (pLV1017) encoding resistance to antibiotics and expressing catechol 2,3-dioxygenase was transferred into two facultatively anaerobic gram-negative bacteria, isolated from the excrement of A. vulgare. Presumed transconjugants of the facultatively anerobic gram-negative bacteria given above were isolated from the leaves and soil (four strains) and the excrement of the invertebrates (11 strains). They carried the same plasmids and exhibited the same enzymatic activity as the respective inoculant strains; for most of them, however, DNA fingerprints were slightly different. Transfer from S. faecalis JH2-2 to B. thuringiensis var. israelensis of a naturally occurring plasmid, pAMb₁, encoding resistance to erythromycin was observed in vermicompost. Received: 18 November 1997     

Past and present potential of the Adriatic deep sea sediments to produce methane hydrates

Journal of Soils and Sediments - There is a growing understanding that methane hydrates (MHs) distributed globally in permafrost and deep sea sediments present an enormous unconventional reservoir...     

Fumonisins affect the intestinal microbial homeostasis in broiler chickens,predisposing to necrotic enteritis

Fumonisins (FBs) are mycotoxins produced by Fusarium fungi. This study aimed to investigate the effect of these feed contaminants on the intestinal morphology and microbiota composition, and to evaluate whether FBs predispose broilers to necrotic enteritis. One-day-old broiler chicks were divided into a group fed a control diet, and a group fed a FBs contaminated diet (18.6 mg FB1+FB2/kg feed). A significant increase in the plasma sphinganine/sphingosine ratio in the FBs-treated group (0.21 ± 0.016) compared to the control (0.14 ± 0.014) indicated disturbance of the sphingolipid biosynthesis. Furthermore, villus height and crypt depth of the ileum was significantly reduced by FBs. Denaturing gradient gel electrophoresis showed a shift in the microbiota composition in the ileum in the FBs group compared to the control. A reduced presence of low-GC containing operational taxonomic units in ileal digesta of birds exposed to FBs was demonstrated, and identified as a reduced abundance of Candidatus Savagella and Lactobaccilus spp. Quantification of total Clostridium perfringens in these ileal samples, previous to experimental infection, using cpa gene (alpha toxin) quantification by qPCR showed an increase in C. perfringens in chickens fed a FBs contaminated diet compared to control (7.5 ± 0.30 versus 6.3 ± 0.24 log10 copies/g intestinal content). After C. perfringens challenge, a higher percentage of birds developed subclinical necrotic enteritis in the group fed a FBs contaminated diet as compared to the control (44.9 ± 2.22% versus 29.8 ± 5.46%).

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0234-8) contains supplementary material, which is available to authorized users.     

Colonization factors of Campylobacter jejuni in the chicken gut

ABSTRACT: Campylobacter contaminated broiler chicken meat is an important source of foodborne gastroenteritis and poses a serious health burden in industrialized countries. Broiler chickens are commonly regarded as a natural host for this zoonotic pathogen and infected birds carry a very high C. jejuni load in their gastrointestinal tract, especially the ceca. This eventually results in contaminated carcasses during processing. Current intervention methods fail to reduce the colonization of broiler chicks by C. jejuni due to an incomplete understanding on the interaction between C. jejuni and its avian host. Clearly, C. jejuni developed several survival and colonization mechanisms which are responsible for its highly adapted nature to the chicken host. But how these mechanisms interact with one another, leading to persistent, high-level cecal colonization remains largely obscure. A plethora of mutagenesis studies in the past few years resulted in the identification of several of the genes and proteins of C. jejuni involved in different aspects of the cellular response of this bacterium in the chicken gut. In this review, a thorough, up-to-date overview will be given of the survival mechanisms and colonization factors of C. jejuni identified to date. These factors may contribute to our understanding on how C. jejuni survival and colonization in chicks is mediated, as well as provide potential targets for effective subunit vaccine development.