Chemical composition of the Tatra Mountain lakes: Recovery from acidification

Ninety-one lakes distributed along the Tatra Mountains (most of lakes > 1 ha and 65% of lakes > 0.01 ha) were sampled and analysed for ionic and nutrient composition in September 2004 (15 years after reduction in acid deposition). Eighty-one lakes were in alpine zone and ten lakes in Norway spruce forest. The results were compared to similar lake surveys from 1994 (the beginning of water recovery from acidification) and 1984 (maximum acidification). Atmospheric deposition of SO ₄ ^2? and inorganic N decreased 57% and 35%, respectively, in this region from the late 1980s to 2000. Lake water concentrations of SO ₄ ^2? and NO ₃ ^? have decreased both by ～50% on average (to 23 and 19 μmol L^?1, respectively, in 2004) since 1984. While the decrease in SO ₄ ^2? concentrations was stable throughout 1984–2004, most of the NO ₃ ^? decrease occurred from 1994 to 2004. The declines in SO ₄ ^2? and NO ₃ ^? concentrations depended on catchment coverage with vegetation, being most rapid for SO ₄ ^2? in forest lakes and for NO ₃ ^? in rocky lakes. Concentrations of the sum of base cations (dominated by Ca²⁺) significantly decreased between 1984 and 2004, with the highest change in rocky lakes. Most of this decline occurred between 1994 and 2004. Acid neutralising capacity (ANC) did not change in the 1984–1994 period, but increased on average by 29 μmol L^?1 between 1994 and 2004, with the highest change in rocky lakes. Over the last decade, the proportion of lakes with ANC > 150 μmol L^?1 increased from 15% to 21% and that of ANC < 20 μmol L^?1 decreased from 37% to 20%. The highest decline in H⁺ and Al concentrations occurred in the most acid lakes. On a regional basis, no significant change was observed for total phosphorus, total organic nitrogen, and dissolved organic carbon (DOC) in the 1994–2004 period. However, these parameters increased in forest lakes, which exhibited an increasing trend in DOC concentrations, inversely related (P < 0.001) to their decreasing ionic strength (30% on average in 1994–2004).     

Evolution of resident bird breeding phenology in a landscape with heterogeneous resource phenology and carryover effects

It is generally expected that, in environments with pronounced seasonal resource peaks, birds’ reproductive success will be maximised when nestlings’ peak food demand coincides with the timing of high food availability. However in certain birds that stay resident over winter, earlier breeding leads juveniles to join the winter flock earlier, which by the prior residence effect increases their success in breeding territory competition. This trade-off between reproduction and competition may explain why, in certain species, breeding phenology is earlier and asynchronous with the resource. This study extends a previous model of the evolution of breeding phenology in a single habitat type to a landscape with two habitat types: ‘early’ and ‘late’ resource phenology. The offspring’s natal habitat type has a carryover effect upon their competitive ability regardless of which habitat type they settle in to potentially breed. We find that, when the difference in resource phenology between habitats is small (weak carryover effect), breeding phenology in the late habitat evolves to occur earlier and more asynchronously than in the early habitat, to compensate for the competitive disadvantage to juveniles raised there. However if the difference is large (strong carryover effect), then the reproductive cost of earlier breeding outweighs the benefit of the compensation, so instead breeding phenology in the late habitat evolves to become more synchronous with the resource. Recruitment is generally asymmetric, from early to late habitat type. However if the early habitat is less frequent in the landscape or produces fewer offspring, then the asymmetry is reduced, and if there is some natal habitat-type fidelity, then recruitment can have an insular pattern, i.e. most recruits to each habitat type come from that same habitat type. We detail the different scenarios in which the different recruitment patterns are predicted, and we propose that they have implications for local adaptation.     

Auxin-like activity of extract from hypertrophied tissue of <Emphasis Type="Italic">Acacia eburnea</Emphasis> infected with <Emphasis Type="Italic">Ravenelia esculenta</Emphasis>

Ravenelia esculenta Naras. and Thirum. is a rust, pathogenic to Acacia eburnea Willd. The infection leads to hypertrophy changing the morphology with bizarre shapes of plant organs. Healthy and infected tissues were subjected to extraction of IAA and indole derivatives and were estimated by spectrophotometric methods. The hypertrophy produced was presumed to be due to increase in the indole-3-acetic acid (IAA) content in the infected tissue, however, the amount of IAA in infected tissues decreased with the progression of disease. Concomitantly, the infected tissue showed the presence of a novel, slow migrating, indole derivative on TLC. Cultured shoot tips of Withania somnifera were dosed with the methanolic extract of the infected hypertrophied tissue (MEHT) (0.25, 0.5, 0.75, 1.00 and 1.25 mg/l). The stimulation in shoot growth along with profuse rooting was observed in a dose dependent manner with maximum at 1.00 and 1.25 mg/l concentration.     

Spatio-temporal tumour model for analysis and mechanism of action of intracellular drug accumulation

We have developed a one-dimensional tumour simulator to describe the biodistribution of chemotherapeutic drugs to a tumoral lesion and the tumour cell’s response to therapy. A three-compartment model is used for drug dynamics within the tumour. The first compartment represents the extracellular space in which cells move, the second corresponds to the intracellular fluid space (including cell membrane) which is in direct equilibrium with the extracellular space, and the third is a non-exchangeable compartment that represents sequestered drug which is trapped in the nucleus to damage the cellular DNA, directly triggering cell death. Analytical and numerical techniques (Finite Element Method) are used to describe the tumour’s response to therapy and the effect of parameter variation on the drug concentration profiles in the three compartments.     

Fuzzy logic feedback control for fed-batch enzymatic hydrolysis of lignocellulosic biomass

A fuzzy logic feedback control system was developed for process monitoring and feeding control in fed-batch enzymatic hydrolysis of a lignocellulosic biomass, dilute acid-pretreated corn stover. Digested glucose from hydrolysis reaction was assigned as input while doser feeding time and speed of pretreated biomass were responses from fuzzy logic control system. Membership functions for these three variables and rule-base were created based on batch hydrolysis data. The system response was first tested in LabVIEW environment then the performance was evaluated through real-time hydrolysis reaction. The feeding operations were determined timely by fuzzy logic control system and efficient responses were shown to plateau phases during hydrolysis. Feeding of proper amount of cellulose and maintaining solids content was well balanced. Fuzzy logic proved to be a robust and effective online feeding control tool for fed-batch enzymatic hydrolysis.     

Diversity of halophilic microorganisms: Environments,phylogeny, physiology,and applications

The phylogenetic diversity of microorganisms living at high salt concentrations is surprising. Halophiles are found in each of the three domains: Archaea, Bacteria, and Eucarya. The metabolic diversity of halophiles is great as well: they include oxygenic and anoxygenic phototrophs, aerobic heterotrophs, fermenters, denitrifiers, sulfate reducers, and methanogens. The diversity of metabolic types encountered decreases with salinity. The upper salinity limit at which each dissimilatory process takes place is correlated with the amount of energy generated and the energetic cost of osmotic adaptation. Our understanding of the biodiversity in salt-saturated environments has increased greatly in recent years. Using a combination of culture techniques, molecular biological methods, and chemotaxonomic studies, we have obtained information on the nature of the halophilic Archaea as well as the halophilic Bacteria that inhabit saltern crystallizer ponds. Several halophilic microorganisms are being exploited in biotechnology. In some cases, such as the production of ectoine, the product is directly related to the halophilic behavior of the producing microorganism. In other cases, such as the extraction of β-carotene from Dunaliella or the potential use of Haloferax species for the production of poly-β-hydroxyalkanoate or extracellular polysaccharides, similar products can be obtained from non-halophiles, but halophilic microorganisms may present advantages over the use of non-halophilic counterparts. Journal of Industrial Microbiology & Biotechnology (2002) 28, 56–63 DOI: 10.1038/sj/jim/7000176 Received 20 May 2001/ Accepted in revised form 20 June 2001     

Solid cultures of thrips-pathogenic fungi Isaria javanica strains for enhanced conidial productivity and thermotolerance

Entomopathogenic fungi have great potential to control agricultural and horticultural insect pests, however optimizing conidial production systems to demonstrate high productivity and stability still needs additional efforts for successful field application and industrialization. Although many virulent entomopathogenic fungal isolates have been viewed as potential candidates in a laboratory environment, very few of the isolates are being used in practice for application in agricultural fields as commercial products. I. javanicus is an entomopathogenic fungus that is parasitic to various diverse coleopteran and lepidopteran insects and thought good candidate as biopesticdes. In this work, the basic characteristics of two entomopathogenic fungi, I. javanica FG340 and Pf04, were investigated in morphological examinations, genetic identification, and virulence against Thrips palmi, and then the feasibility of various grains substrates for conidial production was assessed, particularly focusing on conidial productivity and thermotolerance. Isaria javanica FG340 and Pf04 conidia were solid-cultured on 12 grains for 14?days in a Petri dish. Of the tested Italian millet, perilla seed, millet and barley-based cultures showed high conidial production. The four-grain media yielded >1?×?10⁹ conidia/g of I. javanica FG340 and Pf04. Pf04 strain had enhanced thermotolerance up to 45?°C when cultured on Italian millet. In application, it was easy to make a conidial suspension using the cultured grains, and several surfactants were tested to release the conidia. This work suggests several possible inexpensive grain substrates by which to promote conidial production combined with enhanced stability against exposure to high temperature.     

The α-<Emphasis Type="SmallCaps">l</Emphasis>-fucosidase from <Emphasis Type="Italic">Sulfolobus solfataricus</Emphasis>

Glycoside hydrolases form hyperthermophilic archaea are interesting model systems for the study of catalysis at high temperatures and, at the moment, their detailed enzymological characterization is the only approach to define their role in vivo. Family 29 of glycoside hydrolases classification groups α-l-fucosidases involved in a variety of biological events in Bacteria and Eukarya. In Archaea the first α-l-fucosidase was identified in Sulfolobus solfataricus as interrupted gene expressed by programmed −1 frameshifting. In this review, we describe the identification of the catalytic residues of the archaeal enzyme, by means of the chemical rescue strategy. The intrinsic stability of the hyperthermophilic enzyme allowed the use of this method, which resulted of general applicability for β and α glycoside hydrolases. In addition, the presence in the active site of the archaeal enzyme of a triad of catalytic residues is a rather uncommon feature among the glycoside hydrolases and suggested that in family 29 slightly different catalytic machineries coexist.     

Diverse origins of enzymes involved in the biosynthesis of chloroplast peptidoglycan

Chloroplasts are believed to be descendants of ancestral cyanobacteria that had peptidoglycan layer between the outer and the inner membranes. Historically, the glaucophyte Cyanophora paradoxa and the rhizopod Paulinella chromatophora were believed to harbor symbiotic cyanobacteria having peptidoglycan, which were conventionally named “cyanelles”. In addition, the complete set of genes involved in the synthesis of peptidoglycan has been found in the moss Physcomitrella patens and some plants and algae. The presence of peptidoglycan-like structures was demonstrated by a new metabolic labeling technique in P. patens. However, many green algae and all known red algae lack peptidoglycan-related genes. That is the reason why we questioned the origin of peptidoglycan-synthesizing enzymes in the chloroplasts of the green algae and plants. We performed phylogenetic analysis of ten enzymes involved in the synthesis of peptidoglycan exploiting the Gclust homolog clusters and additional genomic data. As expected, all the identified genes encoded in the chromatophore genome of P. chromatophora were closely related to cyanobacterial homologs. In the green algae and plants, only two genes, murA and mraY, were found to be closely related to cyanobacterial homologs. The origins of all other genes were diverse. Unfortunately, the origins of C. paradoxa genes were not clearly determined because of incompleteness of published genomic data. We discuss on the probable evolutionary scenarios to explain the mostly non-cyanobacterial origins of the biosynthetic enzymes of chloroplast peptidoglycan: A plausible one includes extensive multiple horizontal gene transfers during the early evolution of Viridiplantae.     

Iron supplementation promotes in vitro shoot induction and multiplication of <Emphasis Type="Italic">Baptisia australis</Emphasis>

C₄ plants can efficiently accumulate CO₂ in leaves and thus reduce wasteful oxygen fixation by the RuBisCO enzyme. Three C₄ enzymes, namely carbonic anhydrase (CA), phosphoenol pyruvate (PEPC) and pyruvate orthophosphate dikinase (PPDK), were over expressed in Oryza sativa L. ssp. indica var. Khitish under the control of green tissue specific promoters PD_54o, PEPC and PPDK, respectively. Integration of these genes was confirmed by Southern hybridization. The relative expression of PEPC, CA and PPDK were, respectively, 6.75, 6.57 and 3.6-fold higher in transgenic plants compared to wild type plants (control). Photosynthetic efficiency of the transgenic plants increased significantly along with a 12?% increase in grain yield compared to wild type plants. Compared to control plants, transgenic plants also showed phenotypic changes such as increased leaf blade size, root biomass, and plant height and anatomical changes such as greater leaf vein number, bundle sheath cells, and bulliform cells. Our findings indicate that the combined over expression of these three enzymes is an efficient strategy for incorporating beneficial physiological and anatomical features that will enable subsequent yield enhancement in C₃ rice plants.