Leveraging browse and grazing forage estimates to optimize index-based livestock insurance.

African pastoralists suffer recurrent droughts that cause high livestock mortality and vulnerability to climate change. The index-based livestock insurance (IBLI) program offers protection against drought impacts. However, the current IBLI design relying on the normalized difference vegetation index (NDVI) may pose limitation because it does not consider the mixed composition of rangelands (including herbaceous and woody plants) and the diverse feeding habits of grazers and browsers. To enhance IBLI, we assessed the efficacy of utilizing distinct browse and grazing forage estimates from woody LAI (LAIW) and herbaceous LAI (LAIH), respectively, derived from aggregate leaf area index (LAIA), as an alternative to NDVI for refined IBLI design. Using historical livestock mortality data from northern Kenya as reference ground dataset, our analysis compared two competing models for (1) aggregate forage estimates including sub-models for NDVI, LAI (LAIA); and (2) partitioned biomass model (LAIP) comprising LAIH and LAIW. By integrating forage estimates with ancillary environmental variables, we found that LAIP, with separate forage estimates, outperformed the aggregate models. For total livestock mortality, LAIP yielded the lowest RMSE (5.9 TLUs) and higher R2 (0.83), surpassing NDVI and LAIA models RMSE (9.3 TLUs) and R2 (0.6). A similar pattern was observed for species-specific livestock mortality. The influence of environmental variables across the models varied, depending on level of mortality aggregation or separation. Overall, forage availability was consistently the most influential variable, with species-specific models showing the different forage preferences in various animal types. These results suggest that deriving distinct browse and grazing forage estimates from LAIP has the potential to reduce basis risk by enhancing IBLI index accuracy.

The type and quantity of dietary fat and carbohydrate alter faecal microbiome and short-chain fatty acid excretion in a metabolic syndrome 'at-risk' population.

INTRODUCTION AND OBJECTIVES: An obese-type human microbiota with an increased Firmicutes:Bacteroidetes ratio has been described that may link the gut microbiome with obesity and metabolic syndrome (MetS) development. Dietary fat and carbohydrate are modifiable risk factors that may impact on MetS by altering the human microbiome composition. We determined the effect of the amount and type of dietary fat and carbohydrate on faecal bacteria and short chain fatty acid (SCFA) concentrations in people 'at risk' of MetS. DESIGN: A total of 88 subjects at increased MetS risk were fed a high saturated fat diet (HS) for 4 weeks (baseline), then randomised onto one of the five experimental diets for 24 weeks: HS; high monounsaturated fat (MUFA)/high glycemic index (GI) (HM/HGI); high MUFA/low GI (HM/LGI); high carbohydrate (CHO)/high GI (HC/HGI); and high CHO/low GI (HC/LGI). Dietary intakes, MetS biomarkers, faecal bacteriology and SCFA concentrations were monitored. RESULTS: High MUFA diets did not affect individual bacterial population numbers but reduced total bacteria and plasma total and LDL-cholesterol. The low fat, HC diets increased faecal Bifidobacterium (P=0.005, for HC/HGI; P=0.052, for HC/LGI) and reduced fasting glucose and cholesterol compared to baseline. HC/HGI also increased faecal Bacteroides (P=0.038), whereas HC/LGI and HS increased Faecalibacterium prausnitzii (P=0.022 for HC/HGI and P=0.018, for HS). Importantly, changes in faecal Bacteroides numbers correlated inversely with body weight (r=-0.64). A total bacteria reduction was observed for high fat diets HM/HGI and HM/LGI (P=0.023 and P=0.005, respectively) and HS increased faecal SCFA concentrations (P<0.01). CONCLUSION: This study provides new evidence from a large-scale dietary intervention study that HC diets, irrespective of GI, can modulate human faecal saccharolytic bacteria, including bacteroides and bifidobacteria. Conversely, high fat diets reduced bacterial numbers, and in the HS diet, increased excretion of SCFA, which may suggest a compensatory mechanism to eliminate excess dietary energy.

Inter-comparison of hemispherical conical reflectance factors (HCRF) measured with four fibre-based spectrometers.

We describe the results of an experiment designed to compare the radiometric performance of four different spectroradiometers in ideal field conditions. A carefully designed experiment where instruments were simultaneously triggered was used to measure the Hemispherical Conical Reflectance Factors (HCRF) of four targets of varying reflectance. The experiment was in two parts. Stage 1 covered a 2 hour period finishing at solar noon, where 50 measurements of the targets were collected in sequence. Stage 2 comprised 10 rapid sequential measurements over each target. We applied a method for normalising full width half maximum (FWHM) differences between the instruments, which was a source of variability in the raw data. The work allowed us to determine data reproducibility, and we found that lower-cost instruments (Ocean Optics and PP Systems) produced data of similar radiometric quality to those manufactured by Analytical Spectral Devices (ASD -here we used the ASD FieldSpec Pro) in the spectral range 400-850 nm, which is the most significant region for research communities interested in measuring vegetation dynamics. Over the longer time-series there were changes in HCRF caused by the structural and spectral characteristics of some targets.

Human 76p: A new member of the gamma-tubulin-associated protein family.

The role of the centrosomes in microtubule nucleation remains largely unknown at the molecular level. gamma-Tubulin and the two associated proteins h103p (hGCP2) and h104p (hGCP3) are essential. These proteins are also present in soluble complexes containing additional polypeptides. Partial sequencing of a 76- kD polypeptide band from these complexes allowed the isolation of a cDNA encoding for a new protein (h76p = hGCP4) expressed ubiquitously in mammalian tissues. Orthologues of h76p have been characterized in Drosophila and in the higher plant Medicago. Several pieces of evidence indicate that h76p is involved in microtubule nucleation. (1) h76p is localized at the centrosome as demonstrated by immunofluorescence. (2) h76p and gamma-tubulin are associated in the gamma-tubulin complexes. (3) gamma-tubulin complexes containing h76p bind to microtubules. (4) h76p is recruited to the spindle poles and to Xenopus sperm basal bodies. (5) h76p is necessary for aster nucleation by sperm basal bodies and recombinant h76p partially replaces endogenous 76p in oocyte extracts. Surprisingly, h76p shares partial sequence identity with human centrosomal proteins h103p and h104p, suggesting a common protein core. Hence, human gamma-tubulin appears associated with at least three evolutionary related centrosomal proteins, raising new questions about their functions at the molecular level.

Gut microbiota and health: connecting actors across the metabolic system.

Overweight-related metabolic diseases are an important threat to health in the Western world. Dietary habits are one of the main causative factors for metabolic syndrome, CVD and type 2 diabetes. The human gut microbiota is emerging as an important player in the interaction between diet and metabolic health. Gut microbial communities contribute to human metabolism through fermentation of dietary fibre and the result of intestinal saccharolytic fermentation is production of SCFA. Acetate, propionate and butyrate positively influence satiety, endocrine system, glucose homeostasis, adipogenesis, lipid oxidation, thermoregulation, hepatic gluconeogenesis, endothelial function and gut barrier integrity, and these mechanisms have all been linked to protection from type 2 diabetes, hypertension and cardiovascular health. The gut microbiota is also involved in bile acid metabolism and regulating their cell signalling potential, which has also been shown to modify pathways involved in metabolic health. Similarly, the gut microbiota renders recalcitrant plant polyphenols into biologically active small phenolic compounds which then act systemically to reduce metabolic disease risk. This review summarises how dietary patterns, specific foods and a healthy lifestyle may modulate metabolic health through the gut microbiota and their molecular cross-talk with the host.

Organization of ventral tegmental area projections to the ventral tegmental area-nigral complex in the rat.

The ventral tegmental area (VTA) is a nodal link in reward circuitry. Based on its striatal output, it has been subdivided in a caudomedial part which targets the ventromedial striatum, and a lateral part which targets the ventrolateral striatum [Ikemoto S (2007) Dopamine reward circuitry: two projection systems from the ventral midbrain to the nucleus accumbens-olfactory tubercle complex. Brain Res Rev 56:27-78]. Whether these two VTA parts are interconnected and to what extent the VTA innervates the substantia nigra compacta (SNc) and retrorubral nucleus (RR) are critical issues for understanding information processing in the basal ganglia. Here, VTA projections to the VTA-nigral complex were examined in rats, using Phaseolus vulgaris leucoagglutinin (PHA-L) as anterograde tracer. The results show that the dorsolateral VTA projects to itself, as well as to the dorsal tier of the SNc and RR, largely avoiding the caudomedial VTA. The ventrolateral VTA innervates mainly the interfascicular nucleus. The components of the caudomedial VTA (the interfascicular, paranigral and caudal linear nuclei) are connected with each other. In addition, the caudomedial VTA (especially the paranigral and caudal linear nuclei) innervates the lateral VTA, and, to a lesser degree, the SNc and RR. The caudal pole of the VTA sends robust, bilateral projections to virtually all the VTA-nigral complex, which terminate in the dorsal and ventral tiers. Modest inputs from the medial supramammillary nucleus to ventromedial parts of the VTA-nigral complex were also identified. In double-immunostained sections, PHA-L-labeled varicosities were sometimes found apposed to tyrosine hydroxylase-positive neurons in the ventral mesencephalon. Overall, the results underscore that VTA projections to the VTA-nigral complex are substantial and topically organized. In general, these projections, like the spiralated striato-nigro-striatal loops, display a medial-to-lateral organization. This anatomical arrangement conceivably permits the ventromedial striatum to influence the activity of the lateral striatum. The caudal pole of the VTA appears to be a critical site for a global recruitment of the mesotelencephalic system.

Selection and characterization of aerobic bacteria capable of degrading commercial mixtures of low-ethoxylated nonylphenols.

AIMS: Isolation and characterization of new bacterial strains capable of degrading nonylphenol ethoxylates (NPnEO) with a low ethoxylation degree, which are particularly recalcitrant to biodegradation. METHODS AND RESULTS: Seven aerobic bacterial strains were isolated from activated sludges derived from an Italian plant receiving NPnEO-contaminated wastewaters after enrichment with a low-ethoxylated NPnEO mixture. On the basis of 16S rDNA sequence, the strains were positioned into five genera: Ochrobactrum, Castellaniella, Variovorax, Pseudomonas and Psychrobacter. Their degradation capabilities have been evaluated on two commercial mixtures, i.e. Igepal CO-210 and Igepal CO-520, the former rich in low ethoxylated congeners and the latter containing a broader spectrum of NPnEO, and on 4-n-nonylphenol (NP). The strains degraded Igepal CO-210, Igepal CO-520 and 4-n-NP all applied at the initial concentration of 100 mg l(-1), by 35-75%, 35-90% and 15-25%, respectively, after 25 days of incubation. CONCLUSIONS: Some of the isolated strains, in particular the Pseudomonas strains BCb12/1 and BCb12/3, showed interesting degradation capabilities towards low ethoxylated NPnEO congeners maintaining high cell vitality. SIGNIFICANCE AND IMPACT OF THE STUDY: Increased knowledge of bacteria involved in NPnEO degradation and the possibility of using the isolated strains in tailored process for a tertiary biological treatment of effluents of wastewater treatment plants.

Anaerobic codigestion of the mechanically sorted organic fraction of a municipal solid waste with cattle manure in packed microcosms under batch conditions.

Packed microcosms, consisting of 0.6 L-flask filled with tire chips (TC, a non-cost-recyclable non-biodegradable material) or ceramic cubes, were employed in the wet batch mesophilic anaerobic codigestion of a mechanically sorted organic fraction of a municipal solid waste with cattle manure. Two different waste mixtures were digested within four successive batch experiments, performed by collecting the digested waste and by refilling each microcosm with the same experimental mixture. Methane production yields related to the first experiment were comparable to those of non-packed identically developed microcosms, while they significantly grew during all the following experiences. No CH4-production lag-phase was observed since the second batch experiment. Similar results were obtained for both packing materials: however, the highest methane yields were achieved within bioreactors packed with TC in the presence of a mixture in which the volatile suspended solids (VSS) provided by the municipal waste represented the 55% of the total ones. Under such condition, a methane yield corresponding to the biochemical methane potential (BMP) calculated through a 6-month experiment with non-packed microcosms (176 ml/gVS) was attained in about 1/4 of the time. Importantly, the BMP can significantly grow up as a consequence of the approach described in this study.

Efferent connections of the rostral linear nucleus of the ventral tegmental area in the rat.

The ventral tegmental area (VTA) is crucially involved in brain reward, motivated behaviors, and drug addiction. This district is functionally heterogeneous, and studying the connections of its different parts may contribute to clarify the structural basis of intra-VTA functional specializations. Here, the efferents of the rostral linear nucleus (RLi), a midline VTA component, were traced in rats with the Phaseolus vulgaris leucoagglutinin (PHA-L) technique. The results show that the RLi heavily innervates the olfactory tubercle (mainly the polymorph layer) and the ventrolateral part of the ventral pallidum, but largely avoids the accumbens. The RLi also sends substantial projections to the magnocellular preoptic nucleus, lateral hypothalamus, central division of the mediodorsal thalamic nucleus, lateral part of the lateral habenula and supraoculomotor region, and light projections to the prefrontal cortex, basolateral amygdala, and dorsal raphe nucleus. A similar set of projections was observed after injections in rostromedial VTA districts adjacent to RLi, but these districts also send major outputs to the lateral ventral striatum. Overall, the data suggest that the RLi is a distinct VTA component in that it projects primarily to pallidal regions of the olfactory tubercle and to their diencephalic targets, the central division of the mediodorsal thalamic nucleus and the lateral part of the lateral habenula. Because the rat RLi reportedly contains a lower density of dopaminergic neurons as compared with most of the VTA, its unusual projections may reflect a non-dopaminergic, putative GABAergic, phenotype, and this distinctive cell population seemingly extends beyond RLi boundaries into the laterally adjacent VTA. By being connected to the central division of the mediodorsal thalamic nucleus (directly and via ventral striatopallidal system) and to the magnocellular preoptic nucleus, the RLi and its surroundings may play a role in olfactory-guided behaviors, which are part of the approach responses associated with appetitive motivational states.

The gut microbiota and lipid metabolism: implications for human health and coronary heart disease.

Coronary heart disease (CHD) is the leading cause of mortality in Western societies, affecting about one third of the population before their seventieth year. Over the past decades modifiable risk factors of CHD have been identified, including smoking and diet. These factors when altered can have a significant impact on an individuals' risk of developing CHD, their overall health and quality of life. There is strong evidence suggesting that dietary intake of plant foods rich in fibre and polyphenolic compounds, effectively lowers the risk of developing CHD. However, the efficacy of these foods often appears to be greater than the sum of their recognised biologically active parts. Here we discuss the hypothesis that beneficial metabolic and vascular effects of dietary fibre and plant polyphenols are due to an up regulation of the colon-systemic metabolic axis by these compounds. Fibres and many polyphenols are converted into biologically active compounds by the colonic microbiota. This microbiota imparts great metabolic versatility and dynamism, with many of their reductive or hydrolytic activities appearing complementary to oxidative or conjugative human metabolism. Understanding these microbial activities is central to determining the role of different dietary components in preventing or beneficially impacting on the impaired lipid metabolism and vascular dysfunction that typifies CHD and type II diabetes. This approach lays the foundation for rational selection of health promoting foods, rational target driven design of functional foods, and provides an essential thus-far, overlooked, dynamic to our understanding of how foods recognised as "healthy" impact on the human metabonome.

Viral expression, oncogenicity, and antigenicity of a mouse salivary gland tumor and two cell lines derived from it.

An in vitro cell line (SGT) derived from a mouse submaxillary gland adenocarcinoma (TGS) containing A and B viral particles maintained its oncogenicity only for newborn isogeneic hosts (C3H/He mice) immunosuppressed with antithymocyte serum. Inoculation into adult isogeneic animals did not cause tumor but provided partial protection against a challenge with TGS cells. The loss of oncogenicity for nonimmunosuppressed isogeneic hosts was accompanied by the acqusition of oncogenicity for adult, nonimmunosuppressed, xenogeneic hosts (golden hamsters) given subcutaneous inoculations of SGT cells on the back. From the tumor grown in the hamster, which is histologically similar to the original tumor of the mouse, an in vitro cell line (HWS) was derived. The comparative analysis of the 2 cell lines, SGT and HWS, led to the following conclusions: (a) the karyological pattern of the 2 cell lines in virtually the same; (b) the cell surface antigenic pattern is similar for the 2 cell lines, as determined by colony inhibition test and cytotoxicty test; (c) the cells of the HWS line behave serologically as a mouse-hamster hybrid, also as determined by colony inhibition and cytotoxicity tests; (d) both cell lines have only intracytoplasmic viral particles of the A type; and (e) agglutination with the plant lectins concanavalin A and wheat germ agglutinin occurs at lower concentrations of agglutinin for HWS cells than for SGT cells.

T-RFLP analysis of bacterial communities in cyclodextrin-amended bioreactors developed for biodegradation of polychlorinated biphenyls.

In this study, T-RFLP analysis was used to determine the structure and spatial distribution of the indigenous bacterial community of an actual-site PCB-contaminated soil treated in aerobic packed-bed loop reactors (PBLRs) in the absence or in the presence of a mixture of randomly methylated beta-cyclodextrins (RAMEB) at 0.5 or 1% w/w. RAMEB was found to significantly enhance the aerobic bioremediation of soil with effects that increased proportionally with the concentration at which it was applied. At the end of treatment (180 days), T-RFLP analysis of the soil samples collected from the top and bottom regions of the PBLRs showed a series of 50 single T-RFs. Remarkably, the number of T-RFs was significantly lower (13-22) in samples collected from different sections of the RAMEB-amended bioreactors with respect to equivalent samples collected from the RAMEB-free reactor. Cluster analysis based on the presence or the absence of T-RFs peaks revealed high similarity, inside each reactor, between the top and bottom parts of its soil bed. Soil samples collected at the top and bottom regions of the two bioreactors amended with RAMEB, clustered together while the equivalent samples of the bioreactor without RAMEB formed a separate cluster which was distantly related to the soil samples obtained from the parallel amended bioreactor. Notably, T-RFLP analyses combined with extensive sequencing of 16S rDNA allowed us to tentatively allocate a series of bacterial species corresponding to specific peaks of the T-RFLP profiles and to determine their phylogenetic affiliation.

Biodegradation of hydroxylated and methoxylated benzoic, phenylacetic and phenylpropenoic acids present in olive mill wastewaters by two bacterial strains.

Two aerobic bacterial strains, a chlorophenol-degrading bacterium characterized in this work as a Ralstonia sp. LD35 on the basis of the sequence of the gene encoding for 16S ribosomal RNA, and Pseudomonas putida DSM 1868, capable of metabolizing 4-methoxybenzoic acid, were tested for their capacity to degrade monocyclic aromatic acids responsible for the toxicity of olive mill wastewaters (OMWs). Both strains possess interesting and complementary degradation capabilities in resting cell conditions: Ralstonia sp. LD35 was found to metabolize 4-hydroxybenzoic, 4-hydroxyphenylacetic, 3,4-dihydroxycinnamic and cinnamic acid, whereas DSM 1868 was capable of metabolizing 4-hydroxy-3-methoxybenzoic, 3,4-dimethoxybenzoic and 4-hydroxy-3,5-dimethoxybenzoic acid, as well as 4-hydroxybenzoic and 4-hydroxyphenylacetic acid. The kinetic parameters describing the growth of the two strains on the same compounds were determined in growing-cell batch conditions, and showed that both strains presented high affinity and high specific growth rates towards all assayed substrates. In addition, the two strains were capable of growing on and extensively biodegrading a mixture of monocyclic aromatic acids commonly found at high concentrations in OMWs, and of growing on a 20% dilution of a natural OMW. All these features make the two strains attractive candidates for the development of a biotechnological process for the biodegradation of aromatic compounds found in OMWs.

Characterization of catechol- and chlorocatechol-degrading activity in the ortho-chlorinated benzoic acid-degrading Pseudomonas sp. CPE2 strain.

Pyrocatechase activity was studied in the Pseudomonas sp. CPE2 strain, which is capable of growing on 2-chlorobenzoic and 2,5-dichlorobenzoic acid, giving rise to catechol and 4-chlorocatechol, respectively, as intermediate metabolites. The CPE2 crude extract was found to metabolize both catechol and 4-chlorocatechol. Enzymatic as well as phenotypic studies performed both on this strain and on a mutant strain lacking the chlorocatechol-degrading genes were consistent with the presence of two catechol-cleaving enzymes, one active mainly against catechol (pyrocatechase I) and the other with broader substrate specificity (pyrocatechase II). The latter enzyme also appeared to be induced when CPE2 cells were grown on 2-chlorobenzoic acid, thus contributing to catechol metabolism, in addition to pyrocatechase I. Despite the presence of a large plasmid in CPE2 cells, the chlorocatechol-degrading genes, highly homologous to the clc operon, were located on the chromosome. The selection at relatively high frequency of mutant strains with altered growth capabilities and which lacked the chlorocatechol-degrading genes suggests a transposon-like character for these catabolic genes in the CPE2 strain.

Polychlorinated biphenyl degradation activities and hybridization analyses of fifteen aerobic strains isolated from a PCB-contaminated site.

Fifteen bacterial strains using biphenyl as sole carbon and energy source, obtained from different positions and depths of a polychlorinated biphenyl (PCB)-contaminated area, were analyzed for their basic metabolic phenotypes and subjected to genomic DNA hybridization screening for the presence of well characterized bph operons such as those of Pseudomonas pseudoalcaligenes KF707 and Rhodococcus globerulus P6. Most of the isolates belonged to the gamma-subdivision (Pseudomonas stutzeri, P. plutida, P. fluorescens and Vibrio logei species) and to the beta-subdivision (genera Alcaligenes, Comamonas, Ralstonia) of the Proteobacteria. All the isolates were able to cometabolize different low chlorinated PCB congeners. Among the dichlorinated biphenyls tested, a lower degradation capacity was observed for the di-ortho substituted congeners, whereas high levels of degradation were observed for the di-meta and di-para isomers, whether they were chlorinated on one or on both rings. The PCB congeners nonsubstituted in the 2,3 or 2,3 and 3,4 positions were also degraded by most of the isolated strains, which were, however, unable to significantly metabolize PCBs with more than 3 chlorine atoms. Five of the isolated strains were also able to degrade some of the tri- and tetrachlorobiphenyls tested. Southern hybridization analysis showed a strong homology between four of the fifteen isolated strains and the bph operon obtained from P. pseudoalcaligenes strain KF707. Conversely, none of the isolates here examined showed homology with the bph operon of R. globerulus strain P6. In line with this, the KF707 bph probe strongly hybridized with DNA of a significant number of bacterial colonies obtained from selected locations in the contaminated area using biphenyl-supplemented minimal medium agar plates.

Use of exogenous specialised bacteria in the biological detoxification of a dump site-polychlorobiphenyl-contaminated soil in slurry phase conditions

The possibility of biologically detoxifying a contaminated soil from an Italian dump site containing about 1500 mg/kg (in dry soil) of polychlorinated biphenyls was studied in the laboratory in this work. The soil, which contained indigenous aerobic bacteria capable of growing on biphenyl or on monochlorobenzoic acids at concentration of about 300 CFU per g of air-dried soil, was amended with inorganic nutrients, saturated with water and treated in aerobic 3-L batch slurry reactors (soil suspension at 20% w/v). Either Pseudomonas sp. CPE1 strain, capable of cometabolising low-chlorinated biphenyls into chlorobenzoic acids, or a bacterial co-culture capable of aerobically dechlorinating polychlorobiphenyls constituted by this bacterium and the two chlorobenzoic acid degrading bacteria Pseudomonas sp. CPE2 strain and Alcaligenes sp. CPE3 strain, were used as inocula (final concentration of about 10(8) CFU/mL for each bacterium), in the absence and in the presence of biphenyl (4 g/kg of air dried soil). Significant soil polychlorobiphenyl depletions were observed in all the reactors after 119 days of treatment. The soil inoculation with the sole CPE1 was found to slightly enhance the polychlorobiphenyl depletions (about 20%) and the soil detoxification; the effect was higher in the presence of biphenyl. The use of the polychlorobiphenyl mineralising bacterial co-culture as inoculum resulted in a strong enhancement of the depletions of both the soil polychlorobiphenyls (from 50 to 65%) and of the original soil ecotoxicity. The bacterial biomass inoculated was found to implant into the soil; the higher specialised biomass availability thus reached in the inoculated soil was probably responsible of a more extensive biodegradation of polychlorobiphenyls and therefore of the higher detoxification yields observed in the inoculated reactors. The soil ecotoxicity, measured through two different soil contact assays, i.e., the Lepidium sativum germination test and the Collembola mortality test, was often found to decrease proportionally with the soil polychlorobiphenyl concentration. Copyright 1999 John Wiley & Sons, Inc.

Cyclodextrin effects on the ex-situ bioremediation of a chronically polychlorobiphenyl-contaminated soil

The possibility of enhancing the intrinsic ex-situ bioremediation of a chronically polychlorinated biphenyl-contaminated soil by using cyclodextrins was studied in this work. The soil, contaminated with a large array of polychlorinated biphenyls and deriving from a dump site where it has been stored for about 10 years, was found to contain indigenous cultivable aerobic bacteria capable of utilising biphenyl and chlorobenzoic acids. The soil was amended with inorganic nutrients and biphenyl, saturated with water, and treated in aerobic batch slurry- and fixed-phase reactors. Hydroxypropyl-beta-cyclodextrin and gamma-cyclodextrin, added to both reactor systems at the concentration of 10 g/L at the 39th and 100th days of treatment, were found to generally enhance the depletion rate and extent of the soil polychlorobiphenyls. Despite some abiotic losses could have affected the depletion data, experimental evidence, such as the production of metabolites tentatively characterized as chlorobenzoic acids and chloride ion accumulation in the reactors, indicated that cyclodextrins significantly enhanced the biological degradation of the soil polychlorobiphenyls. This result has been ascribed to the capability of cyclodextrins of enhancing the availability of polychlorobiphenyls in the hydrophilic soil environment populated by immobilised and suspended indigenous soil microorganisms. Both cyclodextrins were metabolised by the indigenous soil microorganisms at the concentration at which they were used. Therefore, cyclodextrins, both for their capability of enhancing the biodegradation of soil polychlorobiphenyls and for their biodegradability, can have the potential of being successfully used in the bioremediation of chronically polychlorinated biphenyl-contaminated soils. Copyright 1998 John Wiley & Sons, Inc.

Microbial reductive dechlorination of pre-existing PCBs and spiked 2,3,4,5,6-pentachlorobiphenyl in anaerobic slurries of a contaminated sediment of Venice Lagoon (Italy).

Abstract Reductive dechlorination of polychlorinated biphenyls (PCBs) pre-existing (at approximately 1 mg kg(-1)) in a marine sediment of Porto Marghera (Venice Lagoon, Italy) was investigated in anaerobic slurries developed in water of the same contaminated site. Some microcosms were pasteurized whereas others were amended with 2-bromoethanesulfonic acid, molybdate or eubacteria-inhibiting antibiotics (without and in the presence of exogenous carbon sources) to preliminarily characterize the microbial populations involved in the process. Bioconversion of highly chlorinated PCBs into tri- and di-chlorinated, ortho-substituted biphenyls was detected from the 11th week of incubation both in the non-amended and in the pasteurized microcosms, where a significant consumption of sulfate and no methane production were observed. Conversely, no significant PCB transformation was detected in the microcosms with molybdate, where no sulfate consumption and a significant methane evolution occurred. Neither was PCB transformation observed in the microcosms supplemented with antibiotics and exogenous carbon sources, where a strong methane evolution and no sulfate consumption were recorded until the 11th week. The addition of exogenous 2,3,4,5,6-pentachlorobiphenyl showed preferential dechlorination at the meta and para positions, and did not significantly influence the onset of pre-existing PCB dechlorination. These results indicate that endogenous PCBs pre-existing in the marine sediment underwent reductive dechlorination. They also suggest that the process was not 'primed' upon 2,3,4,5,6-pentachlorobiphenyl addition, and was likely to be mediated by sulfate-reducing, spore-forming bacteria.

An aerobic fixed-phase biofilm reactor system for the degradation of the low-molecular weight aromatic compounds occurring in the effluents of anaerobic digestors treating olive mill wastewaters.

An aerobic co-culture, prepared by combining Ralstonia sp. LD35 and Pseudomonas putida DSM1868, was recently found to be capable of extensively degrading many of the hydroxylated and/or methoxylated benzoic, phenylacetic and 3-phenyl-2-propenoic acids occurring in the olive mill wastewaters (OMWs). In the perspective of developing a biotechnological process for the degradation of low-molecular weight (MW) aromatic compounds occurring in the effluents of anaerobic digestors treating OMWs, the capability of this bacterial co-culture of biodegrading a synthetic mix of the above mentioned compounds and the aromatic compounds of an anaerobic OMW-treatment plant effluent in the physiological state of immobilised cells was investigated. Two aerobic fixed-bed biofilm reactors were developed by immobilising the co-culture cells on Manville silica beads and on polyurethane foam cubes. Both supports were found to give rise to a microbiologically stable and biologically active biofilm. The two biofilm reactors were found to be similarly capable of rapidly and completely biodegrading the components of a synthetic mix of nine monocyclic aromatic acids typically present in OMWs and the low-MW aromatic compounds occurring in the anaerobic effluent in batch conditions. However, in the same conditions, the silica bead-packed reactor was found to be more effective in the removal of high-MW phenolic compounds from the anaerobic effluent with respect to the polyurethane cube-packed reactor. These results are encouraging in the perspective of using the co-culture as immobilized cells for developing a continuous biotechnological process for the post-treatment of effluents with low-MW aromatic compounds produced by anaerobic digestors treating OMWs.

Winter biology of Aedes albifasciatus (Diptera: Culicidae) from Córdoba, Argentina.

Host-seeking females of Aedes albifasciatus (Macquart) were collected from April to September 1997, kept under seminatural conditions, and offered sugar solution and blood. Daily survival of females ranged from 0.91 to 0.96, with blood fed females living longer than sugar fed females. Overall, 43% of engorged females completed a gonotrophic cycle, and 15% of them refed and completed a second gonotrophic cycle. The life expectancy of females emerging at the end of summer was longer than those that emerged during winter. Immature developmental time and the developmental threshold were estimated by regression. Embryo development was recorded during autumn, winter, and spring, with a duration of 5-9 d. The developmental threshold for eggs was estimated to be 2.28 degrees C. Egg mortality varied from 0.51 to 0.74. The development time for larva and pupa was between 16 and 29 d and was significantly correlated with temperature. The developmental threshold for larvae and pupae was estimated to be 4.75 degrees C. A greater proportion of females than males emerged when temperatures averaged < or = 18 degrees C. Larval and pupal mortality was high at temperatures below the developmental threshold. Aedes albifasciatus females remained gonotrophically active and immature development continued during winter in Córdoba (10 degrees C isotherm).