Evidences of lateral gene transfer between archaea and pathogenic bacteria

Acquisition of new genetic material through horizontal gene transfer has been shown to be an important feature in the evolution of many pathogenic bacteria. Changes in the genetic repertoire, occurring through gene acquisition and deletion, are the major events underlying the emergence and evolution of bacterial pathogens. However, horizontal gene transfer across the domains i.e. archaea and bacteria is not so common. In this context, we explore events of horizontal gene transfer between archaea and bacteria. In order to determine whether the acquisition of archaeal genes by lateral gene transfer is an important feature in the evolutionary history of the pathogenic bacteria, we have developed a scheme of stepwise eliminations that identifies archaeal-like genes in various bacterial genomes. We report the presence of 9 genes of archaeal origin in the genomes of various bacteria, a subset of which is also unique to the pathogenic members and are not found in respective non-pathogenic counterparts. We believe that these genes, having been retained in the respective genomes through selective advantage, have key functions in the organism’s biology and may play a role in pathogenesis.     

Natural products as starting points for future anti-malarial therapies: going back to our roots?

Background

Population movements along the Thailand-Cambodia border, particularly among highly mobile and hard-to-access migrant groups from Cambodia and Myanmar, are assumed to play a key role in the spread of artemisinin resistance. Data on treatment-seeking behaviours, knowledge and perceptions about malaria, and use of preventive measures is lacking as characteristics of this population prevent them from being represented in routine surveillance and the lack of a sampling frame makes reliable surveys challenging.

Methods

A survey of migrant populations from Cambodia and Myanmar was implemented in five selected rural locations in Thailand along the Thai-Cambodian border using respondent driven sampling (RDS) to determine demographic characteristics of the population, migratory patterns, knowledge about malaria, and health-care -seeking behaviours.

Results

The majority of migrants from Myanmar are long-term residents (98%) with no plans to move back to Myanmar, understand spoken Thai (77%) and can therefore benefit from health messages in Thai, have Thai health insurance (99%) and accessed public health services in Thailand (63%) for their last illness. In comparison, the majority of Cambodian migrants are short-term (72%). Of the short-term Cambodian migrants, 92% work in agriculture, 18% speak Thai, 3.4% have Thai health insurance, and the majority returned to Cambodia for treatment (45%), self-treated (11%), or did not seek treatment for their last illness (27%).

Conclusion

Most highly mobile migrants along the Thai-Cambodia border are not accessing health messages or health treatment in Thailand, increasing their risk of malaria and facilitating the spread of potentially resistant Plasmodium falciparum as they return to Cambodia to seek treatment. Reaching out to highly mobile migrants with health messaging they can understand and malaria diagnosis and treatment services they can access is imperative in the effort to contain the spread of artemisinin-resistant P. falciparum.     

An Investigation of the Soil Property Changes and Heavy Metal Accumulation in Relation to Long-term Wastewater Irrigation in the Semi-arid Region of Iran

Concentrations and spatial distribution of Zn, Cu, Cd, and Pb along two landscapes including a wastewater-irrigated area and a control area were determined to assess the impact of long-term wastewater irrigation and landscape properties on heavy metal contamination. Some disturbed and undisturbed soil samples were taken from soil trenches and soil cores, located on three main landscape positions (upper slope, midslope, and lower slope) in northwestern Iran. The investigation showed that the mean concentration of the heavy metals followed the order Zn > Cu > Pb > Cd in the wastewater-irrigated soil and Pb > Zn > Cu > Cd in the control soils. On average, compared to similar positions in the control region, the wastewater-irrigated regions contained 3.0 (midslope) to 4.9 (lower slope), 2.7 (midslope) to 4.6 (lower slope), 3.3 (upper slope) to 4.1 (lower slope), and 1.7 (upper slope) to 2.6 (lower slope) times higher amounts of Zn, Cu, Cd, and Pb, respectively. Significant positive relationships (P < 0.05) were recorded between the heavy metals concentration with <0.002 mm particle-size fraction and organic matter content, the fractions linked to runoff and soil erosion. It is believed that the two soil fractions play a crucial role in the distribution of the metals along the wastewater-irrigated landscape. Despite the significant increase of heavy metals (P < 0.05) in the wastewater-irrigated soils compared with control soils, the concentration of all evaluated metals was below the maximum accepted limits (Zn < 300 mg/kg, Cu < 100 mg/kg, Cd < 5 mg/kg, and Pb < 100 mg/kg), and grouped as “not-enriched” to “moderately-enriched” categories regarding the topsoil enrichment index. Overall, the lower slope was shown to be more contaminated with the heavy metals compared to the other positions.     

Au-Catalyzed Silicon Nanoneedles Synthesized from Pure Silane Gas at Various RF Powers on Silicon Substrate by VHF-PECVD

Silicon nanonowires (SiNWs) were synthesized with approximately 100 nm/min by very-high-frequency plasma-enhanced chemical vapor deposition method via a vapor–liquid–solid mechanism. Pure silane gas was deposited on Au-coated silicon substrates at various radio frequency (RF) powers varied from 5 to 20 W, keeping other deposition parameters constant. Synthesized SiNWs were needle-like shape with an ultra-sharp tip diameter of about 10 nm and a length about 3 μm, which differs from the standard cylindrical nanowire produced by similar techniques. Furthermore, it was shown that the average length of nanoneedles augmented with the increase of RF power. High-resolution transition electron microscopy displayed that the nanowires were composed of a crystalline Si core with an amorphous oxide shell. Raman spectroscopy also revealed the presence of crystalline Si in the grown Si nanoneedles.     

Interleukin-6 enhances insulin secretion by increasing glucagon-like peptide-1 secretion from L cells and alpha cells

Exercise, obesity and type 2 diabetes are associated with elevated plasma concentrations of interleukin-6 (IL-6). Glucagon-like peptide-1 (GLP-1) is a hormone that induces insulin secretion. Here we show that administration of IL-6 or elevated IL-6 concentrations in response to exercise stimulate GLP-1 secretion from intestinal L cells and pancreatic alpha cells, improving insulin secretion and glycemia. IL-6 increased GLP-1 production from alpha cells through increased proglucagon (which is encoded by GCG) and prohormone convertase 1/3 expression. In models of type 2 diabetes, the beneficial effects of IL-6 were maintained, and IL-6 neutralization resulted in further elevation of glycemia and reduced pancreatic GLP-1. Hence, IL-6 mediates crosstalk between insulin-sensitive tissues, intestinal L cells and pancreatic islets to adapt to changes in insulin demand. This previously unidentified endocrine loop implicates IL-6 in the regulation of insulin secretion and suggests that drugs modulating this loop may be useful in type 2 diabetes.     

Filamentous fungi in good shape: microparticles for tailor-made fungal morphology and enhanced enzyme production

Filamentous fungi such as Aspergillus?niger are important biocatalysts for industrial production of various enzymes as well as organic acids or antibiotics. In suspended culture these microorganisms exhibit a complex morphology which typically has a strong influence on their production properties. In this regard, we have recently shown that the addition of inorganic micro particles to the culture medium is a straightforward and elegant approach to precisely tame fungal morphology. For A.?niger a full range of morphological forms from pellets with different diameters to free mycelium could be adjusted by supplementation with talc powder. Aluminium oxide particles similarly affected morphology, showing that this effect is largely independent of the chemical particle composition.?Exemplified for different recombinant A.?niger strains enzyme production could be strongly enhanced by the addition of microparticles. This was demonstrated for the production of fructofuranosidase, an important high-value biocatalyst for pre-biotic fructo-oligosaccharides, by recombinant A.?niger. In a microparticle enhanced fed-batch process, a highly productive mycelium could be achieved. The enzyme titre of 2800?U/mL finally reached was more then tenfold higher then that of any other process reported so far. Here we provide additional insights into the novel production process. This includes the confirmation of the highly selective production of the target enzyme fructofuranosidase using MALDI-TOF?MS analysis. Moreover, we show that the obtained enzyme suspension can be efficiently used with minimal pre-treatment for the biosynthesis of short chain fructooligosaccharides of the inulin type, such as 1-kestose and 1-nystose, prebiotics with substantial commercial interest. In particular, these compounds are highly attractive for human consumption, since they have been shown to reduce the risk of colon cancer. In summary, the use of microparticles opens a new avenue of engineering fungal morphology into the desired form for specific production processes.     

Planktic foraminiferal biostratigraphy of theMaastrichtian sedimentary beds at Ain Mdeker,northeastern Tunisia

Maastrichtian Foraminifera from the sedimentary beds at Ain Mdeker are recorded and identified. The fauna examined is found to be clearly Tethyan in composition. On the basis of this fauna, four planktic foraminiferal zones, the Globotruncana falsostuarti Zone, the Rugotruncana gansseri Zone, the Abathomphalus mayaroensis Zone and the Globotruncana falsocalcarata Zone are distinguished in the Maastrichtian of the sequence studied. These zones are futher compared with the zones established in equivalent strata in the sequence at El Kef, the most complete sequence in Tunisia. In addition to the index species only the biostratigraphically most important species from the fauna studied are illustrated.     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

Solid-phase parallel synthesis of 4-beta-D-ribofuranosylpyrazolo[4,3-d]pyrimidine nucleosides

The synthesis of pyrazolo[4,3-d]pyrimidine nucleoside library using solid-phase parallel synthesis methodology is described. Glycosylation of the trimethylsilyl (TMS) derivative of 1- and 2-(methyl)-1H and 2H-pyrazolo[4,3-d]pyrimidine-5,7-(4H, 6H)-dione (5) with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose in the presence of TMS triflate provided two novel protected nucleosides 6 and 7. The structures of 6 and 7 were assigned by 1H and 2D NMR experiments. Nucleosides 6 and 7 were then transformed to the key intermediates 12 and 15 respectively. Reaction of 12 and 15 with MMTCl resin in the presence of 2,6-lutidine afforded the necessary scaffolds B and C. Different amines (96) were introduced selectively by nucleophilic substitution on scaffolds B and C using solid-phase parallel semi-automated synthesizer. Cleavage of the products from the solid support with 30% HFIP in a parallel fashion yielded nucleoside libraries simultaneously, and they were analyzed and characterized by high-throughput LC-MS.