Effects of common soil anions and pH on the uptake and accumulation of perchlorate in lettuce

A mechanistic understanding of perchlorate () entry into plants is important for establishing the human health risk associated with consumption of contaminated produce and for assessing the effectiveness of phytoremediation. To determine whether common soil anions affect uptake and accumulation in higher plants, a series of competition experiments using lettuce (Lactuca sativa L.) were conducted between (50 nM) and (4–12 mM), (1–10 mM), or Cl⁻ (5–15 mM) in hydroponic solution. The effects of (0–5 mM) and pH (5.5–7.5) on uptake were also examined. Increasing in solution significantly reduced the amount of taken up by green leaf, butter head, and crisphead lettuces. Sulfate and Cl⁻ had no significant effects on uptake in lettuce over the concentrations tested. Increasing pH significantly reduced the amount of taken up by crisphead and green leaf lettuces, whereas increasing significantly reduced uptake in butter head lettuce. The inhibition by across all lettuce genotypes suggests that may share an ion carrier with , and the decrease in uptake with increasing pH or provides macroscopic evidence for cotransport across the plasma membrane.     

Long-term changes in nutrient concentrations of the Changjiang River and principal tributaries

We present long-term nutrient data on the Changjiang River (Yangtze River) at six hydrological stations and eight principal tributaries during the period 1958–1985. Three patterns of temporal changes were observed in nitrate and nitrite : minimal variations in the upper catchment area, rapid increases in the middle watershed towards the end of the 1970s, and a gradual increase in the lower drainage basin. Prior to the 1970s, the level of throughout the Changjiang River system remained fairly constant. In the 1980s, however, this changed, with the lowest values in the upper Changjiang changing rapidly to the highest in the middle reaches and then declining slowly but steadily in the lower courses. Compared to and ammonium and soluble reactive phosphorus (SRP) showed smaller increases or no long-term variations, while dissolved silica (DSi) concentration generally decreased at most stations. These three patterns of and changes in the Changjiang River system were reflective of the difference in chemical fertilizer use and landscape features (e.g., slope, soil type and water body area) of the drainage basins of the primary tributaries. The decreases in DSi were most likely attributed to a reduction in suspended sediment loading due to dam constructions and increasing diatom consumption. The increase in and with a reduction in DSi concentrations in the Changjiang River could have significant effects on the stoichiometric balance of nutrients delivered to the East China Sea and the ecosystem in this dynamic region.     

Use of isotopic signatures to assess the food web in a tropical shallow marine ecosystem of Southeastern Brazil

A dual isotope approach was used to assess the relative importance of terrestrial vegetation detritus and other primary producers in the trophic web of Flamengo Sound (Ubatuba, SP), SE Brazil, surrounded by the Atlantic Rain Forest. Primary producers showed distinct C signatures and the observed values suggest that little terrestrial or bulk sediment organic matter enter the food web of the sound. Suspended particulate organic matter (POM, supports the bulk of the consumers, with some contribution by macroalgae . Consumers C values ranged from −17.4 to . At least three trophic levels were detectable in the food web. The N value of POM was , while that of sediment and detritus was . The N values of suspension feeding benthic invertebrates were 8.2–, deposit feeders 8.3–, and carnivores 10.7–. Values for fishes were for detritivore, 11.4– for benthic feeders, 12.4– for zooplanktivores, and for piscivores/benthic invertebrate feeders. Squid mean value was . There is a reasonable agreement between feeding habits information from the literature and N values from this study. In the sound, the first and second trophic steps seem to be about 1– higher than those of similar organisms studied in temperate waters and this may reflect an input of allochtonous anthropogenic nitrogen enriched in ¹⁵N from human activities.     

Topological research on diamagnetic susceptibilities of organic compounds

A novel molecular connectivity index, , based on the adjacency matrix of molecular graphs and novel atomic valence connectivities, , for predicting the molar diamagnetic susceptibilities of organic compounds is proposed. The is defined as: , where and E_i are the atomic valence connectivity and the valence orbital energy of atom i, respectively. A good QSPR model for molar diamagnetic susceptibilities can be constructed from and using multivariate linear regression (MLR). The correlation coefficient r, standard error, and average absolute deviation of the MLR model are 0.9918, 5.56 cgs, and 4.26 cgs, respectively, for the 721 organic compounds tested (training set). Cross-validation using the leave-one-out method demonstrates that the MLR model is highly reliable statistically. Using the MLR model, the average absolute deviations of the predicted values of molar diamagnetic susceptibility of another 360 organic compounds (test set) is 4.34 cgs. The results show that the current method is more effective than literature methods for estimating the molar diamagnetic susceptibility of an organic compound. The MLR method thus provides an acceptable model for the prediction of molar diamagnetic susceptibilities of organic compounds. Figure Plot of calculated vs experimental values of molar diamagnetic susceptibilities using the multivariate linear regression (MLR) model (Eq. 8)     

A bias correction for estimates of effective population size based on linkage disequilibrium at unlinked gene loci*

Analysis of linkage disequilibrium (=mean squared correlation of allele frequencies at different gene loci) provides a means of estimating effective population size (N _e) from a single sample, but this method has seen much less use than the temporal method (which requires at least two samples). It is shown that for realistic numbers of loci and alleles, the linkage disequilibrium method can provide precision comparable to that of the temporal method. However, computer simulations show that estimates of N _e based on for unlinked, diallelic gene loci are sharply biased downwards ( in some cases) if sample size (S) is less than true N _e. The bias is shown to arise from inaccuracies in published formula for when S and/or N _e are small. Empirically derived modifications to for two mating systems (random mating and lifetime monogamy) effectively eliminate the bias (residual bias in % in most cases). The modified method also performs well in estimating N _e in non-ideal populations with skewed sex ratio or non-random variance in reproductive success. Recent population declines are not likely to seriously affect , but if N has recently increased from a bottleneck can be biased downwards for a few generations. These results should facilitate application of the disequilibrium method for estimating contemporary N _e in natural populations. However, a comprehensive assessment of performance of with highly polymorphic markers such as microsatellites is needed.The US Governmentȁ9s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Efficient sampling of RNA secondary structures from the Boltzmann ensemble of low-energy

We adapt here a surprising technique, the boustrophedon method, to speed up the sampling of RNA secondary structures from the Boltzmann low-energy ensemble. This technique is simple and its implementation straight-forward, as it only requires a permutation in the order of some operations already performed in the stochastic traceback stage of these algorithms. It nevertheless greatly improves their worst-case complexity from to , for n the size of the original sequence. Moreover the average-case complexity of the generation is shown to be improved from to in an Boltzmann-weighted homopolymer model based on the Nussinov–Jacobson free-energy model. These results are extended to the more realistic Turner free-energy model through experiments performed on both structured (Drosophilia melanogaster mRNA 5S) and hybrid (Staphylococcus aureus RNAIII) RNA sequences, using a boustrophedon modified version of the popular software UnaFold. This improvement allows for the sampling of greater and more significant sets of structures in a given time.      

Hydrochemical fluctuations and crustacean community composition in an ephemeral saline lake (Sua Pan,Makgadikgadi Botswana)

Fluctuating hydrochemistry, as a result of extreme hydrological regimes, imposes major physiological constraints on the biota of ephemeral saline lakes. While the inverse relationship between salinity and zooplankton species richness is well-known across salinity gradients, few studies have documented closely the response of zooplankton to seasonal changes in salinity. Weekly sampling during two flood seasons at Sua Pan, an intermittent saline lake in central Botswana demonstrated the importance of spatial and temporal salinity gradients for crustacean community composition, associated with a decline in species richness, from 11 to three species. Conductivity ranged between 320 and 125,800 μS cm⁻¹ during seasonal flooding; changing from dominance by and , Ca²⁺ and Mg²⁺, at the beginning of the floods, to NaCl dominated waters as the lake dried out and salinities increased. pH estimates generally ranged between 8.6 and 10, with maximum values recorded during initial flooding. Crustaceans comprised mainly Branchinella spinosa, Moina belli, Lovenula africana and Limnocythere tudoranceai, all of which occurred across a wide range of salinities, while halotolerant freshwater species (Metadiaptomus transvaalensis, Leptestheria striatochonca and the ostracods Plesiocypridopsis aldabrae, Cypridopsis newtoni and a newly identified Potamocypris species) disappeared above conductivities of 1,500 μS cm⁻¹. A unique crustacean composition in southern Africa was attributed to Sua Pans’ rare chemical composition among southern African saline lakes; flood waters on Sua Pan contained a higher proportion of Na⁺ and , and less K⁺, Mg²⁺ and than over 80% of records from salt pans elsewhere in southern African. The freshwater species of crustaceans in Sua Pan were similar to those found in other southern Africa lakes, and these similarities decreased in lakes with higher pH and proportions of Na, and less SO₄ and Mg in their chemical composition. The predominant saline tolerant species on Sua Pan, however, showed a greater similarity to those in saline lakes in southern and East Africa with higher proportions of and, particularly, Mg²⁺ in their chemical composition. Handling editor: J. M. Melack     

Seven new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from colubrid snakes of Guatemala and a discussion of what to call ellipsoid tetrasporocystic, dizoic coccidia of reptiles

During a survey of Guatemalan herpetofauna in the summers of 1998–2000, 29 presumed new species of Eimeria Schneider, 1875 were found, seven of which have a distinct elongate-ellipsoidal shape (L/W ratio ≥ 1.7) and are described herein. Six of the seven new species are similar in oöcyst length, width and L/W ratio and sporocyst length, width and L/W ratio, lack a micropyle, oöcyst residuum, Stieda body, sub- and parastieda bodies, have a polar granule and sporocyst residuum, and their sporocysts appear to have dehiscence sutures. The seventh is slightly smaller and has sporocysts with a Stieda body. The new species are: E. coniophanes n. sp – whose sporulated oöcysts from Coniophanes fissidens are 29.2×14.9 (27–31×13–16) m, with sporocysts m; E. coniophis n. sp. –from Conophis lineatus are 32.0×16.5 (30–34×14–18) m, with sporocysts m; E. dryomarchoni n. sp. – from Drymarchon corais are 32.2×17.7 (31–34×17–19) m, with sporocysts m; E. leptophis n. sp. – from Leptophis mexicanus are 29.5×17.0 (28–31×16–18) m, with sporocysts m; E. oxybelis n. sp. – from Oxybelis aeneus are 31.8×16.5 (29–33×15–18) m, with sporocysts m; and E. scaphiodontophis n. sp. – from Scaphiodontophis annulatus are 30.0×15.3 (28–33×14–16) m, with sporocysts m. Sporulated oöcysts of E. siboni n. sp. from Sibon nebulata are 24.3×14.2 (21–27×13–16) m, with sporocysts m and with a Stieda body. We conclude that until all aspects of each life-cycle are known, it is prudent at this time to name all tetrasporocystic dizoic coccidia from snakes as members of Eimeria rather than place some of them in Choleoeimeria Paperna & Landsberg, 1989.     

Regional Assessment of N Saturation using Foliar and Root \varvec {\delta}^{\bf 15}{\bf N}

N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar than the regional driver of N deposition. Foliar increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root was more tightly coupled to forest floor properties than was foliar . We observed a pattern of decreasing foliar values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar included species composition and climate. Relationships between foliar and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar , due to the importance of ammonium deposition in this region. Our results suggest that examining values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.     

A Novel Approach for Bioremediation of a Coastal Marine Wastewater Effluent Based on Artificial Microbial Mats

A novel alternative for wastewater effluent bioremediation was developed using constructed microbial mats on low-density polyester. This biotechnology showed high removal efficiencies for nitrogen and phosphorous in a short retention time (48 h): 94% for orthophosphate (7.78 g m³ d⁻¹), 79% for ammonium (11.30 g m⁻³ d⁻¹), 78% for nitrite (7.46 g m⁻³ d⁻¹), and 83% for nitrate (8.55 g m⁻³ d⁻¹). The microbial mats were dominated by Cyanobacteria genera such as Chroococcus sp., Lyngbya sp., and bacteria of the subclass Proteobacteria representative of the Eubacteria Domain. Nitzschia sp. was the dominant Eukaryote Domain. Various N and P substrates in the wastewater permit the growth of self-forming and self-sustaining bacterial, microalgal, and cyanobacterial communities on a polyester support. The result is the continuous, self-sufficient growth of microbial mats. This is an innovative, economical, and environmentally safe alternative for the treatment of wastewater effluents in coastal marine environments.     

Inheritance of foliar stable carbon isotope discrimination and third-year height in Pinus taeda clones on contrasting sites in Florida and Georgia

Quantifying foliar stable carbon isotope discrimination (Δ) is a powerful approach for understanding genetic variation in gas exchange traits in large populations. The genetic architecture of Δ and third-year height is described for more than 1,000 clones of Pinus taeda tested on two contrasting sites. for Δ was 0.14 (±0.03), 0.20 (±0.07), and 0.09 (±0.04) at Florida, Georgia, and across sites, respectively. for stable carbon isotope discrimination ranged from 0.25 (±0.03) at the Florida site to 0.33 (±0.03) at the Georgia site, while the across-site estimate of was 0.19 (±0.02). For third-year height, ranged from 0.13 (±0.05) at the Georgia site to 0.20 (±0.06) at the Florida site with an across-site estimate of 0.09 (±0.05). Broad-sense heritability estimates for third-year height were 0.23 (±0.03), 0.28 (±0.03), and 0.13 (±0.02) at the Florida site, Georgia site, and across sites, respectively. Type B total genetic correlation for Δ was 0.70 ± 0.06, indicating that clonal rankings were relatively stable across sites, while for third-year height, rankings of clones were more unstable across the two trials . Third-year height and Δ were negatively correlated at the parental , full-sib family , and clonal levels, suggesting that genetic variation for Δ in P. taeda may be a result of differences in photosynthetic capacity. We conclude that Δ may be a useful selection trait to improve water-use efficiency and for guiding deployment decisions in P. taeda.     

Probing the interactions of the solvated electron with DNA by molecular dynamics simulations: bromodeoxyuridine substituted DNA

Solvated electrons () are produced during water radiolysis and can interact with biological substrates, including DNA. To augment DNA damage, radiosensitizers such as bromo-deoxyuridine (BUdR), often referred to as an “electron affinic radiosensitizer”, are incorporated in place of isosteric thymidine. However, little is known about the primary interactions of with DNA. In the present study we addressed this problem by applying molecular modeling and molecular dynamics (MD) simulations to a system of normal (BUdR·A)-DNA and a hydrated electron, where the excess electron was modeled as a localized (H₂O)₆ anionic cluster. Our goals were to evaluate the suitability of the MD simulations for this application; to characterize the motion of around DNA (e.g., diffusion coefficients); to identify and describe configurational states of close localization to DNA; and to evaluate the structural dynamics of DNA in the presence of . The results indicate that has distinct space-preferences for forming close contacts with DNA and is more likely to interact directly with nucleotides other than BUdR. Several classes of DNA - contact sites, all within the major groove, were distinguished depending on the structure of the intermediate water layer H-bonding pattern (or its absence, i.e., a direct H-bonding of with DNA bases). Large-scale structural perturbations were identified during and after the approached the DNA from the major groove side, coupled with deeper penetration of sodium counterions in the minor groove. Figure A rare configuration showing direct interaction between the solvated electron and DNA, where (yellow) and N7(A16) are H-bonded. The close approach from the major groove side invokes deep Na⁺ (magenta) penetration into the minor DNA groove (Fig. 7a).     

Factors affecting denitrification in agricultural headwater streams in Northeast Ohio,USA

As a result of increased anthropogenic nitrogen (N) loading in surface waters of agricultural watersheds, there is enhanced interest to understand and quantify N removal mechanisms. Denitrification, an important N removal mechanism in aquatic systems, may contribute to reducing N pollution in agricultural headwater streams. However, the key factors controlling this process in lotic systems remain unclear. The objective of our study was to examine the factors regulating rates of denitrification in the sediments of agricultural headwater streams in the mid-western USA. Denitrification rates were variable among streams and treatments (<0.1–28.0 μg N g AFDM⁻¹ h⁻¹) and on average, were higher than those reported for similar headwater streams. Carbon quantity and quality, and pH had no effect on denitrification, while temperature and nitrate ( ) concentrations had a positive effect on rates of denitrification. Specifically, controlled denitrification following Michaelis-Menten kinetics. We calculated a value of k_m (1.0 mg -N L^-1) that was comparable to other studies in aquatic sediments but was well below the median in-stream concentrations (5.2–17.4 mg -N L⁻¹) observed at the study sites. Despite high rates of denitrification, this removal mechanism is most likely saturated in the agricultural headwater streams we examined, suggesting that these systems are not effective at removing in-stream N. Handling editor: D. Ryder     

Genetic differentiation of Rosa canina (L.) at regional and continental scales

We investigated the genetic differentiation of Rosa canina at regional and continental scales to delineate provenance regions for seed collection. Using RAPD technique, we examined eight populations in Brandenburg (Germany) and 13 samples from Bavaria and Hungary. AMOVA and $\upphiWe investigated the genetic differentiation of Rosa canina at regional and continental scales to delineate provenance regions for seed collection. Using RAPD technique, we examined eight populations in Brandenburg (Germany) and 13 samples from Bavaria and Hungary. AMOVA and -statistics revealed a significant differentiation ( = 0.23, P < 0.0001) between accessions from Brandenburg and the two other regions. The interpopulation differentiation in Brandenburg was low ( = 0.13). We found the greatest interpopulation distance between Hungary and Brandenburg (Hoher Fl?ming, = 0.47) and the lowest between Dahmeland and Hoher Fl?ming (both Brandenburg, = 0.01). UPGMA dendrogram and PCA showed a clear disjunction between Brandenburg and other regions. Due to the outcrossing mating and seed dispersal system, the genetic variation within R. canina populations is moderately high (87% for Brandenburg, 76% for Bavaria and Hungary). The significant genetic differentiation at the continental scale suggests lower gene flow with increasing geographical distance and underlines the usefulness of regional provenances for planting.     

3D-QSAR study of microsomal prostaglandin E<Subscript>2</Subscript> synthase(mPGES-1) inhibitors

Microsomal prostaglandin E₂ synthase (mPGES-1) has been identified recently as a novel target for treating pain and inflammation. The aim of this study is to understand the binding affinities of reported inhibitors for mPGES-1 and further to design potential new mPGES-1 inhibitors. 3D-QSAR-CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) - techniques were employed on a series of indole derivatives that act as selective mPGES-1 inhibitors. The lowest energy conformer of the most active compound obtained from systematic conformational search was used as a template for the alignment of 32 compounds. The models obtained were used to predict the activities of the test set of eight compounds, and the predicted values were in good agreement with the experimental results. The 3D-QSAR models derived from the training set of 24 compounds were all statistically significant (CoMFA; q ² = 0.89, r ² = 0.95, , and CoMSIA; q ² = 0.84, r ² = 0.93, , ). Contour plots generated for the CoMFA and CoMSIA models reveal useful clues for improving the activity of mPGES-1 inhibitors. In particular, substitutions of an electronegative fluorine atom or a bulky hydrophilic phenoxy group at the meta or para positions of the biphenyl rings might improve inhibitory activity. A plausible binding mode between the ligands and mPGES-1 is also proposed.     

Sources of variability in spotted owl population growth rate: testing predictions using long-term mark–recapture data

For long-lived iteroparous vertebrates that annually produce few young, life history theory predicts that reproductive output (R) and juvenile survival should influence temporal variation in population growth rate (λ) more than adult survival does. We examined this general prediction using 15 years of mark–recapture data from a population of California spotted owls (Strix occidentalis occidentalis). We found that survival of individuals ≥1 year old (ϕ) exhibited much less temporal variability , where CV is coefficient of variation, than R and that R was strongly influenced by environmental stochasticity. Although λ was most sensitive ( ; log-transformed sensitivity) to ϕ and much less sensitive to either R or juvenile survival (survival rate of owls from fledging to 1 year old; ), we estimated that R contributed as much as ϕ to the observed annual variability in λ. The contribution of juvenile survival to variability in λ was proportional to its These results are consistent with the hypothesis that natural selection may have favored the evolution of longevity in spotted owls as a strategy to increase the probability of experiencing favorable years for reproduction. Our finding that annual weather patterns that most affected R (temperature and precipitation during incubation) and ϕ (conditions during winter related to the Southern Oscillation Index) were equally good at explaining temporal variability in λ supports the conclusion that R and ϕ were equally responsible for variability in λ. Although currently accepted conservation measures for spotted owl populations attempt to enhance survival, our results indicated that conservation measures that target R may be as successful, as long as actions do not reduce ϕ.     

Anaerobic Ammonium Oxidation (Anammox) in Chesapeake Bay Sediments

Anaerobic ammonium oxidation (anammox) has recently been recognized as a pathway for the removal of fixed N from aquatic ecosystems. However, the quantitative significance of anammox in estuarine sediments is variable, and measurements have been limited to a few estuaries. We measured anammox and conventional denitrification activities in sediments along salinity gradients in the Chesapeake Bay and two of its sub-estuaries, the Choptank River and Patuxent River. Homogenized sediments were incubated with ^14/15N amendments of , , and to determine relative activities of anammox and denitrification. The percent of N₂ production due to anammox (ra%) ranged from 0 to 22% in the Chesapeake system, with the highest ra% in the freshwater portion of the main stem of upper Chesapeake Bay, where water column concentrations are consistently high. Intermediate levels of relative anammox (10%) were detected at locations corresponding to tidal freshwater and mesohaline locations in the Choptank River, whereas anammox was not detected in the tidal freshwater location in the Patuxent River. Anammox activity was also not detected in the seaward end of Chesapeake Bay, where water column concentrations are consistently low. The ra% did not correlate with accumulation rate in anoxic sediment incubations, but ra% was related to water column concentrations and salinity. Anammox bacterial communities were also examined by amplifying DNA extracted from the upper Chesapeake Bay sediment with polymerase chain reaction (PCR) primers that are specific for 16S rRNA genes of anammox organisms. A total of 35 anammox-like sequences were detected, and phylogenetic analysis grouped the sequences in two distinct clusters belonging to the Candidatus “Scalindua” genus.     

Bifurcation Analysis of Genetically Engineered Pacemaking in Mammalian Heart

Genetically engineered pacemaking in ventricular cells has been achieved by down-regulation of the time independent inward rectifying current (I _K1), or insertion of the hyperpolarisation-activated funny current (I _f). We analyse the membrane system (i.e. ionic concentrations clamped) of an epicardial Luo-Rudy dynamic cell model using continuation algorithms with the maximum conductance () of I _K1 and I _f as bifurcation parameters. Pacemaker activity can be induced either via Hopf or homoclinic bifurcations. As _K1 is decreased by ≈74%, autorhythmicity emerged via a homoclinic bifurcation, i.e., the periodicity first appear with infinitely large periods. In contrast, the insertion of _f induced periodicity via a subcritical Hopf bifurcation at _f≈ 0.25 mSμF⁻¹. Stable autorhythmic action potentials occurred at _f > 0.329 mSμF⁻¹.     

Insect cells respiratory activity in bioreactor

Specific respiration rate ( ) is a key parameter to understand cell metabolism and physiological state, providing useful information for process supervision and control. In this work, we cultivated different insect cells in a very controlled environment, being able to measure . Spodoptera frugiperda (Sf9) cells have been used through virus infection as host for foreign protein expression and bioinsecticide production. Transfected Drosophila melanogaster (S2) cells can be used to produce different proteins. The objective of this work is to investigate respiratory activity and oxygen transfer during the growth of different insect cells lines as Spodoptera frugiperda (Sf9), Drosophila melanogaster (S2) wild and transfected for the expression of GPV and EGFP. All experiments were performed in a well-controlled 1-L bioreactor, with SF900II serum free medium. Spodoptera frugiperda (Sf9) cells reached 10.7 × 10⁶ cells/mL and maximum specific respiration rate () of 7.3 × 10⁻¹⁷ molO₂/cell s. Drosophila melanogaster (S2) cells achieved 51.2 × 10⁶ cells/mL and of 3.1 × 10^–18 molO₂/cell s. S2AcGPV (expressing with rabies virus glycoprotein) reached 24.9 × 10⁶ cells/mL and of 1.7 × 10^–17 molO₂/cell s, while S2MtEGFP (expressing green fluorescent protein) achieved 15.5 × 10⁶ cells/mL and  = 1.9 × 10⁻¹⁷ molO₂/cell s. Relating to the Sf9, S2 cells reached higher maximum cell concentrations and lower specific respiration rate, which can be explained by its smaller size. These results presented useful information for scale-up and process control of insect cells.     

Survival Chances of Mutants Starting With One Individual

A simple theoretical model of a Darwinian system (a periodic system with a multiplication phase and a selection phase) of entities (initial form of polymer strand, primary mutant and satellite mutants) is given. First case: one mutant is considered. One individual of the mutant appears in the multiplication phase of the first generation. The probabilities to find N individuals of the mutant after the multiplication phase M of the n-th generation (with probability δ of an error in the replication, where all possible errors are fatal errors) and after the following selection phase S (with probability β that one individual survives) are given iteratively. The evolutionary tree is evaluated. Averages from the distributions and the probability of extinction are obtained. Second case: two mutants are considered (primary mutant and new form). One individual of the primary mutant appears in the multiplication phase of the first generation. The probabilities to find N _p individuals of the primary mutant and N _m individuals of the new form after the multiplication phase M of the n-th generation (probability ɛ of an error in the replication of the primary mutant giving the new form) and after the following selection phase S (probabilities β _p and β _m that one individual each of the primary mutant and of the new form survives) are given iteratively. Again the evolutionary tree is evaluated. Averages from the distributions are obtained. The online version of the original article can be found at .