Macroinvertebrate communities of mediterranean ponds (North Iberian Plateau): importance of natural and human-induced variability

1. The effects of natural and human‐induced variability on the composition of macroinvertebrate communities of 28 ponds located in the North Iberian Plateau (Spain) were studied to determine the best predictors of community structure. 2. Constrained ordination was used to identify the main factors explaining the among‐pond variance in abundance (as catch per unit effort) of total macroinvertebrate and Chironomidae assemblages and trophic structure (functional feeding groups). 3. Variance partitioning showed that human disturbance (represented by a pond condition index, total phosphorus concentration and pesticides) was the best predictor of macroinvertebrate community structure, whereas factors, such as habitat and biotic variables were of secondary importance. Factors controlling the chironomid community were broadly similar to those acting on the whole community of macroinvertebrates. In contrast, trophic structure was mainly determined by habitat and biotic variables. 4. Our results show that macroinvertebrates may be used as effective indicators of the ecological status of Mediterranean ponds. The Chironomidae deserve special attention because they were the dominant group in the study ponds and the strongest explanatory variable for their distribution was degradation.     

Effect of prebiotic substances on growth,fatty acid profile and probiotic characteristics of <Emphasis Type="Italic">Lactobacillus brevis</Emphasis> NM101-1

Utilization of both probiotics and prebiotics in diet supplements and food products has gained a great interest because of their health benefits. In the present study, the effect of 6 commercially available prebiotic substances on the growth, acidifying activity, fatty acid profile and probiotic characteristics of Lactobacillus brevis NM101-1 was investigated in vitro for the development of synbiotic preparations. The results indicated the selective fermentability of prebiotics by the probiotic bacterial strain and absence of metabolism by pathogenic bacteria. Garlic and onion extracts as well as chicory flour as sources of inulin were the best carbon sources for growth and acidifying activity of the strain. The addition of onion extract to the medium exerted a significant influence on acetic acid production. However, the highest biosynthesis of lactic acid was recorded in the presence of glucose. Supplementation of MRS medium with prebiotic substances caused an increase in the ratio of unsaturated to saturated fatty acids of bacterial cells. Furthermore, resistance to gastrointestinal conditions, hydrophobicity and inhibition of bacterial pathogens as international guidelines for probiotics were enhanced by a combination of probiotic L. brevis and prebiotics which indicated that a convenient prebiotic substance have to be chosen for each probiotic bacterial strain for potential synbiotic preparation.     

Improvement of Lactobacillus brevis NM101-1 grown on sugarcane molasses for mannitol,lactic and acetic acid production

The conversion of sugarcane molasses for the production of lactic acid, acetic acid, and mannitol was enhanced by subjecting Lactobacillus brevis NM101-1 wild strain to various doses of gamma irradiation. Four mutants (LM-1-LM-4) obtained at gamma ray doses of 30, 60, 90, and 120 Gy produced higher levels of lactic acid, acetic acid, and mannitol than the wild-type. Among all the mutants tested, LM-3 strain showed the highest mannitol and acetic acid production which reached 198.95 and 96.86 g/l, respectively. On the other hand, mutant LM-1strain exhibited the best performance with respect to lactic acid production (143.73 g/l). Random amplified polymorphic DNA polymerase chain reaction technique (RAPD-PCR) using three primers (RP, R5, and M13) was used in order to detect the variation in DNA profile in response to gamma irradiation treatments. RAPD analysis indicated the appearance and disappearance of DNA polymorphic bands at different gamma ray doses. The results showed the potential of these mutants to be potential candidates for economical production of mannitol, lactic and acetic acids from molasses on a commercial scale.     

Metabolic engineering of Cyanobacteria and microalgae for enhanced production of biofuels and high‐value products

A lot of research has been performed on Cyanobacteria and microalgae with the aim to produce numerous biotechnological products. However, native strains have a few shortcomings, like limitations in cultivation, harvesting and product extraction, which prevents reaching optimal production value at lowest costs. Such limitations require the intervention of genetic engineering to produce strains with superior properties. Promising advancements in the cultivation of Cyanobacteria and microalgae have been achieved by improving photosynthetic efficiency through increasing RuBisCO activity and truncation of light‐harvesting antennae. Genetic engineering has also contributed to final product extraction by inducing autolysis and product secretory systems, to enable direct product recovery without going through costly extraction steps. In this review, we summarize the different enzymes and pathways that have been targeted thus far for improving cultivation aspects, harvesting and product extraction in Cyanobacteria and microalgae. With synthetic biology advancements, genetically engineered strains can be generated to resolve demanding process issues and achieve economic practicality. This comprehensive overview of gene modifications will be useful to researchers in the field to employ on their strains to increase their yields and improve the economic feasibility of the production process.     

Spread and impact of introduced conifers in South America: Lessons from other southern hemisphere regions

The history of conifers introduced earlier elsewhere in the southern hemisphere suggests that recent invasions in Argentina, Brazil, Chile and Uruguay are likely to increase in number and size. In South Africa, New Zealand and Australia, early ornamental introductions and small forestry plantations did not lead to large‐scale invasions, while subsequent large plantations were followed with a lag of about 20–30 years by troublesome invasions. Large‐scale conifer plantation forestry in South America began about 50–80 years later than in South Africa, Australia and New Zealand, while reports of invasions in South America lagged behind those in the latter nations by a century. Impacts of invading non‐native conifers outside South America are varied and include replacement of grassland and shrubland by conifer forest, alteration of fire and hydrological regimes, modification of soil nutrients, and changes in aboveground and belowground biotic communities. Several of these effects have already been detected in various parts of South America undergoing conifer invasion. The sheer amount of area planted in conifers is already very large in Chile and growing rapidly in Argentina and Brazil. This mass of reproductive trees, in turn, produces an enormous propagule pressure that may accelerate ongoing invasions and spark new ones at an increasing rate. Regulations to control conifer invasions, including measures to mitigate spread, were belatedly implemented in New Zealand and South Africa, as well as in certain Australian states, inspired by observations on invasions in those nations. Regulations in South America are weaker and piecemeal, but the existing research base on conifer invasions elsewhere could be useful in fashioning effective regulations in South America. Pressure from foreign customers in South Africa has led most companies there to seek certification through the Forestry Stewardship Council; a similar programme operates in Australia. Such an approach may be promising in South America.     

Synthesis and CYP24A1 inhibitory activity of N-(2-(1H-imidazol-1-yl)-2-phenylethyl)arylamides

A series of N-(2-(1H-imidazol-1-yl)-2-phenylethyl)arylamides were prepared, using an efficient three- to five-step synthesis, and evaluated for their inhibitory activity against human cytochrome P450C24A1 (CYP24A1) hydroxylase. Inhibition ranged from IC₅₀ 0.3–72 μM compared with the standard ketoconazole IC₅₀ 0.52 μM, with the styryl derivative (11c) displaying enhanced activity (IC₅₀ = 0.3 μM) compared with the standard, providing a useful preliminary lead for drug development.     

Parasite genetic differentiation by habitat type and host species: molecular epidemiology of Schistosoma japonicum in hilly and marshland areas of Anhui Province, China

Schistosoma japonicum , a parasite of significant public health importance in parts of China and Southeast Asia, is a true generalist pathogen with over 40 species of mammals suspected as definitive host reservoirs. In order to characterize levels of parasite gene flow across host species and identify the most important zoonotic reservoirs, S. japonicum larvae (miracidia) were sampled from a range of definitive host species in two contrasting habitat types within Anhui Province, China: a low-lying marshland region, and a hilly region, where animal reservoir populations may be predicted to differ substantially. Miracidia samples were genotyped using seven multiplexed microsatellite markers. Hierarchical F -statistics and clustering analyses revealed substantial geographical structuring of S. japonicum populations within Anhui, with strong parasite genetic differentiation between habitat types. Within most villages, there was very little or no parasite genetic differentiation among host species, suggesting frequent S. japonicum gene flow, and thus also transmission, across species. Moreover, the data provide novel molecular evidence that rodents and dogs are potentially very important infection reservoirs in hilly regions, in contrast to bovines in the marshland regions. The parasite genetic differentiation between habitat types might therefore be associated with contrasting host reservoirs. The high levels of parasite gene flow observed across host species in sympatric areas have important implications for S. japonicum control, particularly in hilly regions where control of infection among wild rodent populations could be challenging.