Measurement of eight scalar and dipolar couplings for methine–methylene pairs in proteins and nucleic acids

A new 3D, spin-state-selective coherence transfer NMR experiment is described that yields accurate measurements for eight scalar or dipolar couplings within a spin system composed of a methylene adjacent to a methine group. Implementations of the experiment have been optimized for proteins and for nucleic acids. The experiments are demonstrated for C–C moieties of the third IgG-binding domain from Streptococcal Protein G (GB3) and for C –C groups in a 24-nt RNA oligomer. Chemical shifts of C, C and H (respectively C , C and H ) are dispersed in the three orthogonal dimensions, and the absence of heteronuclear decoupling leads to distinct and well-resolved E.COSY multiplet patterns. In an isotropic sample, the E.COSY displacements correspond to ¹J_CH, ²J_CH2+²J_CH3, ²J_CH, ¹J_CH2+¹J_CH3, ¹J_CH2–²J_H2H3, ¹J_CH3–²J_H2H3, ³J_HH2 and ³J_HH3 for proteins, and ¹J , ²J J , ²J , ¹J +¹J , ¹J J , ¹J J , ³J and ³J in nucleic acids. The experiment, based on relaxation-optimized spectroscopy, yields best results when applied to residues where the methine–methylene group corresponds to a reasonably isolated spin system, as applies for C, F, Y, W, D, N and H residues in proteins, or the C –C groups in nucleic acids. Splittings can be measured under either isotropic or weakly aligned conditions, yielding valuable structural information both through the ³J couplings and the one-, two- and three-bond dipolar interactions. Dipolar couplings for 10 out of 13 sidechains in GB3 are found to be in excellent agreement with its X-ray structure, whereas one residue adopts a different backbone geometry, and two residues are subject to extensive ₁ rotamer averaging. The abundance of dipolar couplings can also yield stereospecific assignments of the non-equivalent methylene protons. For the RNA oligomer, dipolar data yielded stereospecific assignments for six out of the eight C H₂ groups in the loop region of the oligomer, in all cases confirmed by ¹J ^{1} $$" align="middle" border="0"> J , and H resonating downfield of H .Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s10858-005-0175-z.     

The humus layer determines SO<Subscript>4</Subscript><Superscript>2−</Superscript> isotope values in the mineral soil

Biocycling of sulfur (S) has been proposed to play an important role in the recovery of ecosystems following anthropogenic S deposition. Here, we investigated the importance of the humus layer in the biocycling of S in three forested catchments in the Gårdsjön area of southwestern Sweden with differing S inputs and S isotope signature values. These experimental sites consisted of two reference catchments and the Gårdsjön roof experiment catchment (G1), where anthropogenic deposition was intercepted from 1991 until May 2002 by a roof placed over the entire catchment area. Under the roof, controlled levels of deposition were applied, using a sprinkler system, and the only form of S added was marine SO₄²⁻ with a δ of +19.5‰.We installed ion exchange resin bags at the interface between the humus layer and mineral soil at each of the catchments to collect SO₄²⁻ passing through the humus. The resin bags were installed on four occasions, in 1999 and 2000, covering two summer and two winter periods. The ions collected by each bag during these sampling periods were then eluted and their δ values and SO₄²⁻ concentrations determined. The most striking result is that the average δ value in the resin bags was more than 12‰ lower compared to that of the sprinkler water in the G1 roof catchment. There was no increasing trend in the isotope value in the resin bag SO₄²⁻ despite that the roof treatment has been on-going for almost 10 years; the average value for all resin bags was +7.1‰. The highest δ values found in the G1 roof catchment were between +11‰ and +12‰. However, these values were all obtained from resin bags installed at a single sampling location. Throughfall and resin bag δ values were more similar in the two reference catchments: about +7.5‰ in both cases. There was, however, an increase in resin bag δ values during the first winter period, from about +7‰ to +9‰. The resin bag δ value was linearly and positively related (r² = 0.26, p < 0.001) to the amount of SO₄²⁻ extracted from the resin bags, if relatively high amounts (>50 mmol m⁻²) were excluded. High amounts of resin bag SO₄²⁻ seemed to be related to groundwater inputs, as indicated by the δ value. Our results suggest that rapid immobilization of SO₄²⁻ into a large organic S pool may alter the S isotope value and affect the δ values measured in the mineral soil and runoff.     

Formate binding near the redox-active TyrosineD in Photosystem II: consequences on the properties of TyrD

Formate and phosphate affect substantially the rate of tyrosine D (Tyr_D) oxidation and the stability of the radical Tyr in Photosystem II [Hienerwadel R, Boussac A, Breton J and Berthomieu C (1996) Biochemistry 35: 15447–15460]. This observation prompted us to analyze the influence of formate and phosphate on the environment of Tyr_D using FTIR spectroscopy. The ν (CO) IR mode of Tyr at 1503 cm⁻¹ remains unchanged whatever the buffer used at pH 6 and whether formate is present or not in the sample. Similarly, the main IR mode of reduced Tyr_D remains at ≈1250 cm⁻¹ in all tested conditions. We thus conclude that formate does not modify the hydrogen-bonded interactions of Tyr_D and Tyr with neighbouring D2His189 and D2Gln164. In the Tyr_D-state, an IR mode of formate significantly different from that observed in solution, is detected using ¹³C-formate, showing that formate forms a strong electrostatic interaction within PS II. The presence of formate affects also IR bands that may be assigned to an arginine side chain. Upon Tyr formation, formate does not protonate but its binding interaction weakens. A proton uptake by Mes or phosphate buffer is detected, which is not observed when BisTris is used as a buffer. In these latter conditions, IR bands characteristic of the protonation of a carboxylate group of the protein are detected instead. The present IR data and the recent structural model of the Tyr_D environment proposed by Ferreira KN, Iverson TM, Maghlaoui K, Barber J and Iwata S [(2004) Science 303: 1831–1838], suggest that the proton released upon Tyr formation is shared within a hydrogen bonding network including D2Arg294, and CP47Glu364 and that perturbation of this network by formate – possibly binding near D2Arg294 – substantially affects the properties of Tyr_D.     

A set of HA-detected experiments for measuring scalar and residual dipolar couplings

A new set of HCACO based three-dimensional NMR experiments for measuring residual dipolar couplings in proteins is presented. Using spin-state selection and editing in three dimensions, the experiments allow accurate measurement of intraresidual , and scalar and residual dipolar couplings of ¹⁵N/¹³C labeled proteins in D₂O and dilute liquid crystals with minimal spectral crowding. The presented experiments are especially suitable for small or medium sized proline-rich proteins, or proteins that require high pH solvent conditions, making ¹H^N detected experiments unattractive. In addition, the tetrahedral coordination of C is superior to the planar peptide bond for determination of local alignments in partially structured polypeptides. For the efficient use of spectrometer time and to avoid complications arising from the varying magnitude of the alignment tensor during relatively long experiments, the and couplings can also be measured simultaneously in an E.COSY like manner with high accuracy. The pulse sequences are balanced for cross-correlation effects and minimized for relaxation losses. The pulse sequences are tested with a sample of ¹⁵N/¹³C human ubiquitin. We find internuclear vector directions determined from the dipolar couplings to have an excellent correlation with those of ubiquitins refined solution structure.     

Altered expression of an ankyrin-repeat protein results in leaf abnormalities,necrotic lesions,and the elaboration of a systemic signal

Summary The PR-like proteins, class I -1,3-glucanase (GLU I) and chitinase (CHN I), are induced as part of a stereotypic response that can provide protection against viral, bacterial, and fungal pathogens. We have identified two Nicotiana plumbaginifolia ankyrin-repeat proteins, designated lucanohydrolase inding roteins (GBP) 1 and 2, that bind GLU I and CHN I both in vitro and when expressed in yeast cells. Sense as well as antisense transformants of tobacco carrying the GBP1 gene elaborated graft-transmissible acropetally moving signals that induced the downward curling of young leaves. This phenotype was associated with reduced starch, sucrose, and fructose accumulation; the formation of necrotic lesions; and, the induction of markers for the hypersensitive response. GBP1/2 are members of a conserved lant-specific yrin- repeat (PANK) family that includes proteins implicated in carbohydrate allocation, reactive oxygen metabolism, hypersensitive cell death, rapid elicitor responses, virus pathogenesis, and auxin signaling. The similarity in phenotype of PANK transformants and transformants altered in carbohydrate metabolism leads us to propose that PANK family members are multifunctional proteins involved in linking plant defense responses and carbohydrate metabolism.     

High groundwater nitrate concentrations inhibit eutrophication of sulphate-rich freshwater wetlands

During the last 60 years, pollution of the groundwater with has greatly increased in many parts of Europe, as a consequence of excessive use of manure and synthetic fertilisers. Monitoring of groundwater-fed wetlands indicated that sediments with high concentrations had the lowest Fe and concentrations in the pore water. A comparison of two restored open water fens, differing in supply via the groundwater, indicated that the redox potential and the sulphate ( ) reduction rate were lower when the groundwater contained not only but also high concentrations. The lower reduction rates in the -rich open water fen were associated with lower concentrations and the presence of plant species characteristic of clear water. In contrast, the higher reduction rates in the -poor open water fen were associated with very high concentrations and massive development of plant species characteristic of eutrophic environments. Investigations at -rich seepage sites in black alder carrs, showed that high concentrations in the pore water caused chlorosis in the alder carr vegetation, due to lower availability of Fe in the pore water and less Fe uptake by the plants. Experimental desiccation of sediments proved that the -rich seepage sites contained no oxidisable FeS _x , contrary to -poor locations, which became acidified and mobilised extremely high amounts of due to FeS _x oxidation. A laboratory experiment showed that addition to sediments led to reduced releases of Fe, and S^2–, very likely due to the oxidation of reduced Fe and S compounds. Overall, the results confirmed that is an energetically more favourable electron acceptor in anaerobic sediments than Fe and , and that high loads function as a redox buffer, preventing reduction of Fe and . Limited reduction prevents S^2– -mediated mobilisation of from Fe- complexes. At a higher redox potential, reduced Fe, including FeS _x , was oxidised, increasing the content of Fe(III) capable of binding . This prevented increased availability and the concomitant massive development of plant species characteristic of eutrophic environments.     

Compensatory changes in Photosystem II electron turnover rates protect photosynthesis from photoinhibition

Exposure of algae or higher plants to bright light can result in a photoinhibitory reduction in the number of functional PS II reaction centers (n) and a consequential decrease in the maximum quantum yield of photosynthesis. However, we found that light-saturated photosynthetic rates (P_max) in natural phytoplankton assemblages sampled from the south Pacific ocean were not reduced despite photoinhibitory decreases in n of up to 52%. This striking insensitivity of P_max to photoinhibition resulted from reciprocal increases in electron turnover ( )through the remaining functional PS II centers. Similar insensitivity of P_max was also observed in low light adapted cultures of Thalassiosira weissflogii (a marine diatom), but not in high light adapted cells where P_max decreased in proportion to n. This differential sensitivity to decreases in n occurred because was close to the maximum achievable rate in the high light adapted cells, whereas was initially low in the low light adapted cells and could thus increase in response to decreases in n. Our results indicate that decreases in plant productivity are not necessarily commensurate with photoinhibition, but rather will only occur if decreases in n are sufficient to maximize or incident irradiance becomes subsaturating.     

Minimal Functional Unit of Lactate Dehydrogenase

The tetrameric heart isozyme of lactate dehydrogenase (H₄) is modified by p-chloromercuribenzoate (PCMB) to produce the inactive tetramer and then hybridized with native tetrameric muscle isozyme (M₄). The hybrid mixture was isolated by polyacrylamide gel electrophoresis (PAGE) and then stained for enzyme activity and with Coomassie brilliant blue. Only three bands were found on the gels in either case. The hybrid enzymes as isolated by PAGE have half the specific activity of the native muscle enzyme. The electrophoresis properties of HM₃ are very similar to those of HM₃, while the electrophoresis properties of are very similar to those of H₂M₂. The above results strongly suggest that the tetramer having enzymatic activity contains at least two native subunits, and the di-subunit in the tetrameric enzyme is the minimal functional unit.     

Times to exhaustion at 100% of velocity at [(V)\dot]\textO\text2 \dot V{\text{O}}_{\text{2}} max and modelling of the time-limit / velocity relationship in elite long-distance runners

The aim of this study was to measure running times to exhaustion (Tlim) on a treadmill at 100% of the minimum velocity which elicits _{max max} in 38 elite male long - distance runners _max = 71.4 ± 5.5 ml.kg^–1.min^–1 and _max = 21.8 ± 1.2 km.h^–1). The lactate threshold (LT) was defined as a starting point of accelerated lactate accumulation around 4 mM and was expressed in _max. Tlim value was negatively correlated with _max (r = -0.362, p< 0.05) and _max (r = –0.347, p< 0.05) but positively with LT (%v _max) (r = 0.378, p < 0.05). These data demonstrate that running time to exhaustion at _max in a homogeneous group of elite male long-distance runners was inversely related to _max and experimentally illustrates the model of Monod and Scherrer regarding the time limit-velocity relationship adapted from local exercise for running by Hughson et al. (1984) .     

The quantitative genetics of two life history trade-offs in the yellow dung fly in abundant and limited food environments

The trade-offs between body size and development time and between egg size and egg number (clutch size) are central to life history theory, but evidence for them, particularly in terms of genetic correlations, is equivocal. For the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae), we investigated variation in phenotypic and genetic variances and covariances, i.e. heritabilities and genetic correlations, of these life history traits (plus diapause) in benign and stressful larval field or adult laboratory food environments. We found both trade-offs to be weak, as evidenced by low phenotypic and genetic correlations, but stronger in the food limited environments. Broad sense heritabilities were generally significant for all traits considered, whereas the narrow sense heritabilities for egg and clutch size were nil. With regard to the question of how environmental stress affects heritabilities, we found a whole range of responses within one single species depending on the traits considered. All three possible patterns occurred, i.e. increased h² due to increased V_G or decreased decreased h² due to increased and no change in h² due to increased V_G and V_P. These can be explained by the particular ecological circumstances yellow dung flies face in their natural environment. Nevertheless, the majority of patterns was consistent with the idea that stressful conditions amplify phenotypic differences between genotypes. Such variable responses of traits even within one organism underscores the complexity of this issue and may well explain the multiple patterns found in various organisms.Co-ordinating editor: Leimar     

The Influence of Hydroregime on Catch, Abundance And Recruitment of the Catfish, Chrysichthys Nigrodigitatus (Bagridae) and the Bonga, Ethmalosa Fimbriata (Clupeidae) of Southeastern Nigeria's Inshore Waters

This paper investigates the relationship between the hydroclimatic parameters (rainfall and flood index) and the catch, stock abundance and recruitment of the catfish, Chrysichthys nigrodigitatus (Bagridae) and the bonga, Ethmalosa fimbriata (Clupeidae) of southeastern Nigeria's inshore waters. For C. nigrodigitatus, most peaks in the mean biomass and recruitment curves occurred during the 'wet' years, i.e., years for which the percentage deviations of rainfall and flood index from their means remained above their averages. Catch and abundance respectively showed good positive linear correlation with the flood index. E. fimbriata behaved differently; some peaks in the and curves occurred in the 'wet' and some in the 'dry' years; and there was no correlation between the annual catch of bonga and either the rainfall or the flood index. The hypothesis, that linear relationships exist between the interannual variations in the hydroregime and the yearly fluctuations in the catch and population structure of some coastal and estuarine fishes, holds true for the catfish, C. nigrodigitatus, but not for bonga, E. fimbriata.     

Larmor frequency selective model free analysis of protein NMR relaxation

Summary The Lipari-Szabo dynamical formalism is extended by setting the time constants of the Lorentzian terms to and . This analysis is compared to the earlier proposed three-parameter extended model free formalism with regard to the range of equivalence and the advantages of the simplified two-parameter (S _inff ^sup2 ,S _infH ^sup2 ) and (S _inff ^sup2 ,S _infN ^sup2 ) representations. Spectral density components are calculated and compared to those obtained from the spectral density analysis formalism. Protein relaxation data, commonly analyzed in terms of the two-parameter representation, may correspond to a dynamically heterogeneous behaviour that is more appropriately represented in terms of a fast limit order parameter and a second, lower frequency order parameter.     

Estimating the Accuracy of Protein Structures using Residual Dipolar Couplings

It has been commonly recognized that residual dipolar coupling data provide a measure of quality for protein structures. To quantify this observation, a database of 100 single-domain proteins has been compiled where each protein was represented by two independently solved structures. Backbone ¹H–¹⁵N dipolar couplings were simulated for the target structures and then fitted to the model structures. The fits were characterized by an R-factor which was corrected for the effects of non-uniform distribution of dipolar vectors on a unit sphere. The analyses show that favorable values virtually guarantee high accuracy of the model structure (where accuracy is defined as the backbone coordinate rms deviation). On the other hand, unfavorable values do not necessarily suggest low accuracy. Based on the simulated data, a simple empirical formula is proposed to estimate the accuracy of protein structures. The method is illustrated with a number of examples, including PDZ2 domain of human phosphatase hPTP1E. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

A new medium formulation for <Emphasis Type="Italic">in vitro</Emphasis> rooting of carob tree based on leaf macronutrients concentrations

Experiments were performed to optimize the macronutrients concentrations for in vitro rooting of Ceratonia siliqua micropropagated shoots. Several dilutions of Murashige and Skoog (MS) medium were tested: full-strength MS, half-strength MS ( MS), and MS + full N. The frequency of in vitro rooting was enhanced when the MS was used (50 % rooted shoots). Mature leaves from 20 – 30 year-old carob trees and from 2 year-old micropropagated plants were collected and the concentrations of macronutrients (N, P, K, Ca, Mg) assessed. Based on the mineral composition of the leaves a new medium was formulated and compared with the previous ones showing an increment of the rooting frequency to 80 %. Moreover, shoots rooted in the new medium did not show symptoms of apical necrosis that occurred in the other tested media.     

Energetics of vocalization by an anuran amphibian (Hyla versicolor)

Summary The metabolic demands of vocalization byHyla versicolor were determined by measuring oxygen consumption and whole body lactate content of calling animals. A stepwise multiple regression analysis identified both calling rate (calls/h) and call duration (s/call) as significant determinants of oxygen consumption during calling. These two variables accounted for 84% of the total variation in oxygen consumption observed in calling frogs. Aerobic metabolism increased linearly with calling rate and call duration, reaching a peak value of 1.7 ml O₂/(g·h) at the highest vocalization effort. For comparison, metabolic rates of the same individuals were also measured during short bouts of vigorous locomotor exercise induced by mechanical stimulation. The mean value of was only 62% of the peak , and 5 of 13 frogs had rates of oxygen consumption during calling that exceeded their . Whole body lactate levels were measured in two samples of calling frogs, one collected early in the evening (2100–2115 h) and the other 1.5 h later (2230–2245 h). The frogs in the second sample had significantly lower lactate levels (0.10 mg/g) than the frogs collected early in the evening (0.22 mg/g). Hence, vocalization does not entail the use of anaerobic metabolism, although lactate levels may be slightly elevated at the onset of an evening of calling. Calling rates of unrestrained frogs in a large chorus were measured at regular intervals during an evening. During the first half hour of calling, rates increased gradually from an initial mean value of 600 calls/h at 2030 h to nearly 1400 calls/h at 2100 h. These data indicate that acoustic advertisement byHyla versicolor is among the most energetically expensive activities regularly undertaken by any anuran, and indeed, is the most demanding yet measured in an ectothermic vertebrate.Abbreviations resting rate of oxygen consumption - maximum rate of oxygen consumption - rate of oxygen consumption during forced exercise - rate of oxygen consumption during calling     

Chronic nitrate additions dramatically increase the export of carbon and nitrogen from northern hardwood ecosystems

A long-term field experiment was initiated to simulate chronic atmospheric N deposition, a widespread phenomenon in industrial regions of the world. Eight years of experimental nitrate ( ) additions (3 g -N m^–2 per year) to four different northern hardwood forests located along a 500 km geographic gradient dramatically increased leaching losses of -N, dissolved organic carbon (DOC), and dissolved organic nitrogen (DON). During the last two water years, the average increase in solution -N and DON leaching from the -amended plots was 2.2 g N m^–2, equivalent to 72% of the annual experimental N addition. Results indicate that atmospheric N deposition may rapidly saturate some northern hardwood ecosystems across an entire biome in the upper Great Lakes Region of the USA. Changes in soil C and N cycling induced by chronic N deposition have the potential in this landscape to significantly alter the flux of DOC and DON from upland to aquatic ecosystems. Michigan Gradient study site characteristics are similar to those of European forests most susceptible to N saturation.     

EEG Activity in the Process of Measuring-off of Time Intervals by Humans

We recorded EEG from sites C3 and C4 in an experimental situation with internal counting-off of a 20-sec-long time interval, whose beginning and end were limited by the tested subject by pushing a button; 65 adult men and women took part in the tests. In the first experimental series, the subject obtained no real information on the accuracy in production of the interval. In the second series, such information was displayed by feedback visual signals. We calculated means of the measured intervals ( ), coefficient of variation of the realizations (CV), and, in the series with the real feedback, successfulness of measuring-off (normalized number of fits within an acceptable range of the standard interval, 19 to 21 sec). Analysis of the data obtained in the first experimental series for the entire tested group demonstrated the existence of a reverse dependence between the modal frequency of EEG beta rhythm recorded from the left hemisphere in the course of measuring-off of the interval and the value. In the second series, we found significant negative correlation between the beta rhythm power in both hemispheres and CV, that between the alpha rhythm power in the left hemisphere and , and positive correlation between the alpha rhythm frequency in the left hemisphere and successfulness of the interval counting-off. Analysis of the dynamics of EEG of each tested subject demonstrated the existence of mostly reverse dependences between the powers of a few EEG rhythms and duration of the produced interval. We hypothesize that the frequencies of the alpha and beta EEG oscillations play the role of significant indices reflecting the speed of the internal clock of the individual. We also emphasize the complex nature and the high individual variability of the EEG pattern in the course of measuring-off of time intervals.     

Kinetic Modeling of Energy Metabolism and Superoxide Generation in Hepatocyte Mitochondria

Direct nonenzymatic oxidation of semiquinone by oxygen is one of the main sources of superoxide radicals in mitochondria. Using all the known data on hepatocyte mitochondria, we have revealed the correlation between the rate of superoxide generation by the bc ₁complex and the transmembrane potential (). Assuming that the main electrogenic stage of the Qcycle is the electron transfer between the cytochrome bhemes, then the rate of superoxide generation sharply increases when grows from 150 to 180 mV. However, this interrelation is ambiguous. Indeed, the increase of the generation rate with the growth of the potential can occur faster when succinate dehydrogenase is inhibited by malonate than when external ADP is exhausted. When the potential is changed by adding phosphate or potassium (K⁺), the rate of production remains constant, although the comparison of the rates at the same reveals the effect of phosphate or potassium. It turned out that the rate of generation is a function of rather than any of its components. Phosphate and K⁺have practically no influence on , since the change in is compensated by pH. The rate of superoxide generation by the bc ₁complex is a multiple function of the electron-transfer activity of enzymes, the processes determining the membrane potential (e.g., loading), and the oxygen concentration. The kinetic model proposed in this work may serve to understand how the superoxide production is regulated.     

Association between heart rate variability and training response in sedentary middle-aged men

The effect of exercise training on heart rate variability (HRV) and improvements in peak oxygen consumption ( _peak) was examined in sedentary middle-aged men. The HRV and absolute and relative _peak of training (n = 19) and control (n = 15) subjects were assessed before and after a 24-session moderate intensity exercise training programme. Results indicated that with exercise training there was a significantly increased absolute and relative _peak (P < 0.005) for the training group (12% and 11% respectively) with no increase for the control group. The training group also displayed a significant reduction in resting heart rate; however, HRV remained unchanged. The trained subjects were further categorized into high (n = 5) and low (n = 5) HRV groups and changes in _peak were compared. Improvements in both absolute and relative _peak were significantly greater (P > 0.005) in the high HRV group (17% and 20% respectively) compared to the low HRV group (6% and 1% respectively). The groups did not differ in mean age, pretraining oxygen consumption, or resting heart rate. These results would seem to suggest that a short aerobic training programme does not alter HRV in middle-aged men. Individual differences in HRV, however, may be associated with _peak response to aerobic training.     

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.