Gain and Loss of Multiple Genes During the Evolution of Helicobacter pylori

Sequence diversity and gene content distinguish most isolates of Helicobacter pylori. Even greater sequence differences differentiate distinct populations of H. pylori from different continents, but it was not clear whether these populations also differ in gene content. To address this question, we tested 56 globally representative strains of H. pylori and four strains of Helicobacter acinonychis with whole genome microarrays. Of the weighted average of 1,531 genes present in the two sequenced genomes, 25% are absent in at least one strain of H. pylori and 21% were absent or variable in H. acinonychis. We extrapolate that the core genome present in all isolates of H. pylori contains 1,111 genes. Variable genes tend to be small and possess unusual GC content; many of them have probably been imported by horizontal gene transfer. Phylogenetic trees based on the microarray data differ from those based on sequences of seven genes from the core genome. These discrepancies are due to homoplasies resulting from independent gene loss by deletion or recombination in multiple strains, which distort phylogenetic patterns. The patterns of these discrepancies versus population structure allow a reconstruction of the timing of the acquisition of variable genes within this species. Variable genes that are located within the cag pathogenicity island were apparently first acquired en bloc after speciation. In contrast, most other variable genes are of unknown function or encode restriction/modification enzymes, transposases, or outer membrane proteins. These seem to have been acquired prior to speciation of H. pylori and were subsequently lost by convergent evolution within individual strains. Thus, the use of microarrays can reveal patterns of gene gain or loss when examined within a phylogenetic context that is based on sequences of core genes

Circular and inclusive utilization of alternative proteins: A European and Mediterranean perspective

Current European, and particularly Mediterranean, agricultural production systems heavily depend on protein imports to cover the nutritional needs of farmed animals and fish. To increase their resilience, the EU is in search of efficient, sustainable, and locally produced alternative proteins. Insects and algae have recently gained much attention due to their ability to bioconvert agro-industrial side-streams into valuable resources. Legumes are known for their high protein content; however, certain species, such as lupins and fava beans, have been overlooked and underused as food and feed. Additionally, microbial fermentation can be used in parallel with insects, algae, and legumes, to efficiently transform them into food and feed. This contribution describes the challenges and chances associated with the utilization of these alternative protein sources for food and feed applications

Utilization of Renewable Biomass and Waste Materials for Production of Environmentally-Friendly, Bio-based Composites

The introduction of renewable biomass into a polymer matrix is an option competing with other possibilities, such as energy recovery and/or re-use in the carbonized state, or production of chemicals, such as, in the case of ligno-cellulosic waste, concentrates on the production of simple sugars, then possibly leading to the development of biopolymers. These competitive applications have also some interest and market, however with a considerable energy, water and materials consumption, due also to the not always high yielding. Other possibilities for renewable biomass are therefore being used as fillers to increase mechanical performance of polymers or to allow e.g., the absorption of toxic chemicals. This review concentrates on the use of biomass as close as possible to the “as received” state, therefore avoiding whenever suitable any thermal treatment. More specifically, it focuses on its introduction into the three categories of oil-based (or bio-based replacement) of engineered polymers, into industrial biopolymers, such as poly(lactic acid) (PLA) and self-developed biopolymers, such as thermoplastic starch (TPS)

Anaerobic biodegradation of organochlorine pesticides in contaminated soil - Significance of temperature and availability

Anaerobic biodegradation of the pesticides: ¿-hexachlorocyclohexane, methoxychlor, o,p'- and p,p'-DDT in field polluted soil was tested at 12, 22 and 30 °C, using methanogenic granular sludge as inoculum. The contaminants were removed quite effectively at all temperatures and their removal rates increased 1.2–1.7 times with the increase in temperature. In most cases pesticide concentrations after an initial substantial decline remained almost constant until the end of experiment. These residual concentrations were also temperature dependent and they were 1.4–8.2 times higher at 12 °C than at 30 °C. DDT was degraded via DDD and accumulation of this metabolite was lower (19–64%) than the corresponding amount of removed DDT, especially at higher temperatures. Further transformation of DDD was confirmed by formation of p,p'-dichlorobenzophenone. Additional experiment demonstrated that removal was limited to readily desorbing fractions of pesticides, while their desorption-resistant fractions persisted in the soil. However, DDD metabolite was only partially removed despite its good desorbabilit

Food waste as nutrient source in heterotrophic microalgae cultivation

Glucose, free amino nitrogen (FAN), and phosphate were recovered from food waste by fungal hydrolysis using Aspergillus awamori and Aspergillus oryzae. Using 100. g food waste (dry weight), 31.9. g glucose, 0.28. g FAN, and 0.38. g phosphate were recovered after 24. h of hydrolysis. The pure hydrolysate has then been used as culture medium and nutrient source for the two heterotrophic microalgae Schizochytrium mangrovei and Chlorella pyrenoidosa, S. mangrovei and C. pyrenoidosa grew well on the complex food waste hydrolysate by utilizing the nutrients recovered. At the end of fermentation 10-20. g biomass were produced rich in carbohydrates, lipids, proteins, and saturated and polyunsaturated fatty acids. Results of this study revealed the potential of food waste hydrolysate as culture medium and nutrient source in microalgae cultivation. © 2013 Elsevier Ltd