Enhanced methane production in a two-phase anaerobic digestion plant, after CO2 capture and addition to organic wastes.

Cost-effective technologies are needed to reach the international greenhouse gas (GHG) reduction targets in many fields, including waste and biomass treatment. This work reports the effects of CO(2) capture from a combustion flue gas and its use in a newly-patented, two-phase anaerobic digestion (TPAD) process, to improve energy recovery and to reduce CO(2) emissions. A TPAD process, fed with urban wastewater sludge, was successfully established and maintained for several months at pilot scale. The TPAD process with injection of CO(2) exhibits efficient biomass degradation (58% VSS reduction), increased VFA production during the acidogenic phase (leading to VFA concentration of 8.4 g/L) and high biomethane production (0.350 S m(3)/kg(SSV); 0.363 S m(3)/m(3)(react) · d). Moreover, CO(2) intake in the acid phase has a positive impact on the overall GHG balance associated to biomethane production, and suggests an improved solution for both emission reduction and biomass conversion into biomethane.

Adhesion, autoaggregation and hydrophobicity of 13 strains of Bifidobacterium longum.

To identify bacterial traits related to adhesion ability in human bifidobacteria, 13 strains of Bifidobacterium longum isolated from human gastric juice and intestine were studied. Strains were tested for their capability to adhere to Caco-2 cells and classified as adhesive (Adh+) or non-adhesive (Adh-). Adh+ and Adh- strains were then investigated for their autoaggregation ability and surface hydrophobicity. Comparing the properties of Adh+ and Adh-, we observed that strains were able to adhere to cell monolayers if they autoaggregate and manifest a good degree of hydrophobicity as determined by microbial adhesion to hydrocarbons. These two traits could be used for preliminary screening to identify potentially adherent isolates.

Autoaggregation and adhesion ability in a Bifidobacterium suis strain.

On the basis of autoaggregation ability, two different phenotypes (Agg+ and Agg-) were selected from a strain (BSu895) of Bifidobacterium suis. The relationship between autoaggregation and adhesion of bacteria to intestinal tissue was investigated by observing the adhesivity of the two phenotypic variants to ileum and colon tissue pieces collected from six new-born piglets. The results suggest that there is a good relationship between autoaggregation and adhesion as variant Agg+ (autoaggregating) has a stronger adhesion ability than Agg- (non-autoaggregating).

Modification of muscle proteins IEF patterns in a fish Lebistes reticulatus, related to diet, immunization and genetic selection.

The effects of some environmental and genetic factors on the isoelectric focusing (IEF) patterns of muscle proteins from a fish Lebistes reticulatus (Cyprinodonts) were investigated. Of two diets applied the restricted one resulted in a loss of bands in the IEF patterns of the treated fishes muscle homogenate. Instead immunization gave an increase in both number and intensity of IEF bands in (4.0-6.0; 7.0-7.9) pH ranges which are typical of immunoglobulins. Lastly IEF patterns from random and assortative mating animals were compared, resulting in loss of IEF-bands in the inbred lines. Results showed that IEF of muscle proteins could be an excellent method to evaluate the response by fish phenotypes to environmental or genetic factors.

Karyotypic variability in plants of Solanum melongena regenerated from callus grown in presence of culture filtrate of Verticillium dahliae.

Plantlets were regenerated from calli derived from leaf expiants of three genotypes of Solanum melongena (two parental genotypes and their hybrid). The cytological analysis showed that a) plants regenerated were all mixoploid, b) toxic medium (basal medium added with filtrate culture of Verticillium dahliae) was able to evidence karyotypic differences between genotypes not displayed by plants regenerated from callus grown on control medium, c) chromosomal mosaicism persists up to plant maturity and also in the selfed progeny. The results are discussed in terms of a selective process involving genes controlling chromosome number and/or a direct effect of toxic medium on the activity of the same genes.

[Proposed model for evaluation of toxicity in antineoplastic chemo-hormonotherapy]. / Proposta di un modello di valutazione della tossicità in chemio-ormonoterapia antiblastica.

A detailed code for the evaluation of side-effects due to antiblastics in accordance with clinical, pharmacological and chronobiological parameters is described. Eight types of toxicity are recognised: systemic or local, cutaneous and adnexal, gastroenteric, haematochemical, cardiovascular, respiratory, genital and urinary, and nervous. Improvement of the objectivity and comparability of results in clinical oncology is proposed by means of a balanced points system for the expression of such effects, and methods for the summary expression of the toxicity of a single case or a uniform group of cases. The method of evaluation proposed also permits statistical comparison between different treatment protocols.

Univariate and multivariate analysis on phenotypic divergence in Phleum.

An analysis of phenotypic and genetic variability was performed on Phleum ambiguum populations obtained by vegetative propagation and grown in different environments. The investigation on a single character and the canonical analysis on several plant traits indicate that, while genetic variability (h(2)) is essentially constant, phenotypic variance and covariance are affected by different environments and successive clonations. The observed changes seem not to be reversible when plants, transferred to a different environment, are returned to the original one. Within-clones variability seems to be affected by environmental conditions without being directly related to them. The results reported seem to be in good agreement with the phenotypic divergence hypothesis.

Differential mutagenic response in selected lines of Drosophila melanogaster.

The mutagenic efficiency of ionizing radiations has been tested on different lines of Drosophila melanogaster. It has been shown that differential lethal effects are obtained when irradiated females from different lines are mated to flies carrying heterozygous lethal genes. The results seem not to be attributable to differential expression of the lethality in the various crosses performed with the irradiated flies. This might suggest that gene activity is involved in the expression of the mutagenic effects of radiations.

A multivariate analysis of dominance inDrosophila.

Eleven wing measurements in twoDrosophila melanogaster lines (Canton and FLL) and their reciprocal crosses were analyzed by a multivariate technique in order to investigate changes in variability when dominance is manifested. FLL line was obtained by artificial selection for short wing applied on one measurement on the rightwing. Differences between left and right wing were observed in variabilities after selection. The comparison between F1 and parental populations shows that there is strong evidence for non-additivity which is manifested by a component of the variability due to multiple regression. This is interpreted as meaning that relationships between characters are affected in the heterozygote in a non-additive way, apparently due to interactions among the developmental patterns of the characters considered. It is suggested that a "character" should be defined in such a way as to include its developmental patterns, in order to achieve a better understanding of the dominance phenomenon.

Interaction between artificial and natural selection.

In order to understand how divergence may appear within a gene pool without limitations on gene flow, experiments were performed to investigate whether the genetic structure of a population may be effective in controlling the response to natural selection. Starting from plateaued populations of Drosophila melanogaster selected for wing length on the two sexes separately, the response to natural selection was studied after artificial selection had been discontinued. The results show that populations derived from artificial selection applied to the different sexes respond to subsequent natural selection in dissimilar ways, so as to suggest that the relationships between fitness and wing length have been changed. A second experiment comparing the response to natural and to artificial reversed selection suggests that different genes or gene complexes may be involved in wing length determination: these different genes show a dissimilar response in the different sexes and to natural and artificial selection. This variety of responses suggests that the interactions of different genes or gene complexes with artificial and natural selection could possibly lead to differentiation within the population.

Quantitative inheritance and divergence inDrosophila populations.

Divergent sub-populations were obtained following relaxation of artificial selection for short wing in a population ofDrosophila melanogaster. Different results were obtained by relaxing the selection pressure in lines resulting from different selection procedures. The divergence was actually observed between lines derived by reciprocal crosses between vestigial and wild-type heterozygotes belonging to the same selection line. There was a difference in phenotypic variability in the two sub-lines from the start, which might be responsible for the differential response to natural selection. No difference in reproductive fitness has been detected between the divergent lines. The results can not be easily understood in the framework of an additive polygenic model; it is suggested that some complex interaction may be involved, acting on the developmental processes. It seems, however, safe to suggest that the divergence observed is determined by factors which are present in the FM line.

Differential response to selection on the two sexes in Drosophila melanogaster.

Artificial selection for short wing was performed in two Drosophila melanogaster populations with partially different gene pools: the C populations were derived from a Canton stock while the H lines were derived from a cross between Canton and a b, cn, vg strain. It is shown that in both populations selection on females (CF, HF) was more effective than selection on males (CM, HM). This difference cannot be explained in terms of differences in additive genetic variability between the two sexes because: (1) both sexes contribute to the genetic variability utilized by selection applied to one sex only, and (2) switching selection pressure on females in the M lines does not result in a response comparable to that obtained in the F populations; this rules out almost completely recombination as the responsible agent for the differences between the selection limits reached by M and F selections.-These results, together with several additional observations concerning sexual dimorphism, fitness and the effect of natural selection, suggest that a complex interaction should be involved in the differential response of M and F lines, controlling the wing length phenotype.

The relationship between fitness and response to selection in Drosophila melanogaster.

The relationship between the selection response exhibited by a morphological trait and the correlated response observed on fitness values has been investigated to improve our understanding of micro-and macro-evolutionary processes. The research was designed to test the validity of the "homeostatic" and "metric deviation" models (Robertson 1956). The results show that: 1) correlated changes in fertility values are larger when selection for minus-variant wing length is applied to males than when it is performed on females, 2) within each of the selected lines, M, F and MF, the reproductive fitness of the populations obtained from vg/vg x +/vg crosses differs from that of the populations derived from +/vg X vg/vg crosses, 3) reproductive fitness values of populations derived from vg/vg X +/vg crosses are fairly constant in selected lines obtained by means of different selective procedures, while mean wing length changes; the corresponding populations from +/vg X vg/vg crosses show, on the contrary, a proportionality between fitness and selected trait values. The lack of consistency of these results with the currently accepted hypotheses on the relationship between selection response and correlated changes in fitness leads to the conclusion that the two models considered do not satisfactorily interpret our results; these are better explained by a developmental relationship between fitness and selected trait.

Selection and recombination in Drosophila melanogaster.

Artificial selection for wing length in Drosophila melanogaster resulted in changed crossing-over frequencies between three marker genes on the 2nd chromosome, b, cn and vg.The results suggest that artificial selection is a causal agent in producing the observed changes; moreover it is suggested that the modifications in cross-over frequency are controlled by extra-nuclear factors.