Temperature and sex dependent effects on cardiac mitochondrial metabolism in Atlantic cod (Gadus morhua L.)

To test the hypothesis that impaired mitochondrial respiration limits cardiac performance at warm temperatures, and examine if any effect(s) are sex-related, the consequences of high temperature on cardiac mitochondrial oxidative function were examined in 10 °C acclimated, sexually immature, male and female Atlantic cod. Active (State 3) and uncoupled (States 2 and 4) respiration were measured in isolated ventricular mitochondria at 10, 16, 20, and 24 °C using saturating concentrations of malate and pyruvate, but at a submaximal (physiological) level of ADP (200 µM). In addition, citrate synthase (CS) activity was measured at these temperatures, and mitochondrial respiration and the efficiency of oxidative phosphorylation (P:O ratio) were determined at [ADP] ranging from 25–200 µM at 10 and 20 °C. Cardiac morphometrics and mitochondrial respiration at 10 °C, and the thermal sensitivity of CS activity (Q₁₀=1.51), were all similar between the sexes. State 3 respiration at 200 µM ADP increased gradually in mitochondria from females between 10 and 24 °C (Q₁₀=1.48), but plateaued in males above 16 °C, and this resulted in lower values in males vs. females at 20 and 24 °C. At 10 °C, State 4 was ~10% of State 3 values in both sexes [i.e. a respiratory control ratio (RCR) of ~10] and P:O ratios were approximately 1.5. Between 20 and 24 °C, State 4 increased more than State 3 (by ~70 vs. 14%, respectively), and this decreased RCR to ~7.5. The P:O ratio was not affected by temperature at 200 μM ADP. However, (1) the sensitivity of State 3 respiration to increasing [ADP] (from 25 to 200 μM) was reduced at 20 vs. 10 °C in both sexes (K_m values 105±7 vs. 68±10 μM, respectively); and (2) mitochondria from females had lower P:O values at 25 vs. 100 μM ADP at 20 °C, whereas males showed a similar effect at 10 °C but a much more pronounced effect at 20 °C (P:O 1.05 at 25 μM ADP vs. 1.78 at 100 μM ADP). In summary, our results demonstrate several sex-related differences in ventricular mitochondrial function in Atlantic cod, and suggest that myocardial oxidative function and possibly phosphorylation efficiency may be limited at temperatures of 20 °C or above, particularly in males. These observations could partially explain why cardiac function in Atlantic cod plateaus just below this species׳ critical thermal maximum (~22 °C) and may contribute to yet unidentified sex differences in thermal tolerance and swimming performance.     

Parameter estimation for a temperature-dependent development model of Thrips palmi Karny (Thysanoptera: Thripidae)

Development of immature Thrips palmi Karny was investigated at 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and 35 °C, 20–40% RH and a photoperiod of 14:10 (L:D) h. Developmental time decreased with increasing temperature up to 32.5 °C in all stages. The total developmental time was longest at 12.5 °C (64.2 days) and shortest at 32.5 °C (9.2 days). The lower developmental threshold was 10.6, 10.6, 9.1, and 10.7 °C for egg, larva, prepupa, and pupa, respectively. The thermal constant required to complete the respective stage was 71.7, 59.2, 18.1, and 36.8DD. The lower threshold temperature and thermal constant were 10.6 °C and 183.3DD, respectively, for total immature development. The nonlinear relationship between developmental rate and temperature was well described by the modified Sharpe and DeMichele biophysical model (r² = 0.905–0.998). The distribution of developmental completion of each stage was described by the 3-parameter Weibull function (r² = 0.855–0.927). The temperature-dependent developmental models of T. palmi developed in this study could be used to predict its seasonal phenology in field and greenhouse vegetable crops.     

Relationship between zinc levels and plasma leptin in hemodialysis patients

Recent evidences suggested a possible relationship between zinc deficiency and leptin levels in pathogenesis of anorexia in chronic kidney disease. The present study addressed the relationship between zinc and leptin in hemodialysis (HD) patients.MethodsFifty HD patients (54.3 ± 12.7 years old, 62% men) were studied and compared to 21 healthy volunteers (50.7 ± 15.7 years old, 43% men). Biochemical data, serum zinc, plasma leptin, IL-6, TNF-α and C-Reactive Protein levels were determined. Anthropometric parameters, food intake and appetite score were also assessed.ResultsThe leptin levels were higher in HD patients (16.1 μg/mL (0.21–118.25) vs 6.0 μg/mL (0.50–23.10)) in healthy volunteers (p = 0.04), whereas serum zinc levels were lower (54.5 ± 16.3 μg/dL) compared to healthy volunteers (78.4 ± 9.4 μg/dL) (p = 0.0001). The plasma leptin was correlated negatively with plasma zinc (r = ?0.33; p = 0.007), energy (r = ?0.38; p = 0.002) and protein intake (r = ?0.34; p = 0.006) and, positively correlated with BMI (r = 0.54; p = 0.0001), % body fat (r = 0.70; p = 0.0001) and conicity index (r = 0.46; p = 0.001). Plasma zinc was associated with hemoglobin (r = 0.30; p = 0.04) and negatively associated with TNF-α (r = ?0.37; p = 0.002) and C-Reactive Protein (r = ?0.37; p = 0.004). There was no correlation among Zn, leptin and appetite score in these patients.ConclusionThis study showed that low plasma zinc levels are negatively associated with high leptin levels in HD patients.     

Clostridium difficile survives minimal temperature recommended for cooking ground meats

We quantified the thermal inhibitory effect of 71 °C (recommended for cooking ground meats), and re-heating at 85 °C, on food- and food-animal-derived Clostridium difficile spores. All C. difficile strains tested (n = 20) survived 71 °C for 2 h, but 90% died within 10 min when re-heated at 85 °C. Current cooking recommendations would need revision to include C. difficile.     

Temperature-dependent development of overwintering Sericinus montela Gray (Lepidoptera: Papilionidae) pupae and its validation

The developmental time and survival of overwintering Sericinus montela Gray pupae were studied at four constant temperatures (15.0, 20.0, 25.0, and 30.0 °C), 40 ± 10% relative humidity, and 10:14 h light:dark cycle. The developmental time of both sexes decreased with increasing temperature between 15.0 °C (70.18 days for females and 55.28 days for males) and 30.0 °C (19.60 days for females and 13.78 days for males). The development periods of females were longer than those of males at each constant temperature. The relationship between the developmental rate and temperature was fitted by a linear model and a nonlinear developmental rate model (Lactin 1). The mortality of overwintered S. montela pupae was lowest at 25.0 °C (16.7%) and highest at 15.0 °C (36.7%). The lower developmental thresholds were 12.38 and 12.16 °C for females and males, respectively. The distribution of development completion for females and males was described by the two-parameter Weibull distribution equation (r² = 0.87 for females and r² = 0.94 for males). The date for the cumulative 50% adult emergence was within one or two days of that predicted using the Lactin 1 model. The temperature-dependent developmental model for S. montela could be applied to predict the timing of spring emergence in different geographical locations and will be helpful in developing a full-cycle phenology model for S. montela.     

Oviposition model of Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae)

The longevity and fecundity of Cnaphalocrocis medinalis were investigated at temperatures of 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 32.5, and 35.0 °C. Adult longevity and fecundity were significantly influenced by temperature. Longevity decreased with increasing temperature: it was highest at 15.0 °C (23.6 ± 3.51 days) and lowest at 35.0 °C (6.4 ± 0.48 days). Fecundity was highest at 25.0 °C (170.5 ± 45.54 eggs) and lowest at 17.5 °C (11.0 ± 3.68 eggs). The oviposition period was longest at 20.0 °C (8.0 ± 1.09 days) and shortest at 35.0 °C (2.3 ± 0.48 days). The oviposition model presented in this study consisted of two reproductive components (total fecundity and age-specific cumulative oviposition rate) and a survival component (age-specific survival rate). The relationship between adult developmental rate and temperature was described by the Lactin 2 model (r² = 0.98, p < 0.0001). The age-specific survival rate was well explained by a sigmoid function (r² = 0.97, p < 0.00001). The age-specific cumulative oviposition rate was best described by the three-parameter Weibull function (r² = 0.99, p < 0.00001). Temperature-dependent fecundity was estimated using the Briere-2 model (r² = 0.94, p < 0.007). Daily egg production of C. medinalis in relation to adult age and temperature was estimated.     

Temperature-dependent development of Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) and their validation in semi-field condition

The developmental time and survival of the immature stages of Cnaphalocrocis medinalis Guenée were studied at nine constant temperatures (15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and 35 °C), 40 ± 10% relative humidity, and a 16:8 h light:dark cycle. The total developmental time decreased with increasing temperature between 15 (115.6 days) and 32.5 °C (20.9 days), but increased above 32.5 °C. The relationship between the developmental rate and temperature was fitted by a linear model and three nonlinear developmental rate models (Logan 6, Briere 1, and Shi et al.). The nonlinear shape of temperature-dependent development was best described by the Briere 1 model (r² = 0.99), and this was supported by statistical information criteria. The total mortality of immature C. medinalis was lowest at 25 °C (67.2%) and highest at 35 °C (98.1%). The distribution of the developmental times of each stage was described by the two-parameter Weibull distribution equation (r² = 0.84–0.96). The predicted date for the cumulative 50% moth emergence was within a variation of one day using the Briere 1 model. The temperature-dependent developmental models for C. medinalis could be applied to determine an optimal management strategy for C. medinalis in paddy fields, and will be helpful in developing a full-cycle phenology model for C. medinalis.     

Behavioral and mortality responses of the bivalves Scrobicularia plana and Cerastoderma edule to temperature,as indicator of climate change's potential impacts

Temperature is one of the most important abiotic factors affected by climate change. It determines physiological processes, ecological patterns and establishes the limits of geographic distribution of species. The induced thermal stress frequently results in physiological and behavioral responses and, in extreme cases, may lead to mortality episodes. Scrobicularia plana and Cerastoderma edule behavioral and mortality responses to temperature were evaluated. Specimens were sampled in the Mondego estuary (Portugal), acclimated and exposed to different temperature treatments (5–35 °C). Individual activity and mortality were registered during 120 h laboratory assays. Both species showed a thermal optimum for their activity (S. plana: 15–23 °C; C. edule: 20–23 °C), and survival was mainly affected by high temperature (S. plana: LC50_120 h = 28.86 °C; C. edule: LC50_120 h = 28.01 °C), with 100% mortality above critical values (≥32 °C). Results further indicated that both species are more affected the higher the temperature and the longer the exposure time. This study indicates that the occurrence of extreme climatic events, especially heat waves, may be particularly impairing for these species.     

Mathematical modeling of Microcystis aeruginosa growth and [D-Leu1] microcystin-LR production in culture media at different temperatures

The effect of temperature (26 °C, 28 °C, 30 °C and 35 °C) on the growth of native CAAT-3-2005 Microcystis aeruginosa and the production of Chlorophyll-a (Chl-a) and Microcystin-LR (MC-LR) were examined through laboratory studies. Kinetic parameters such as specific growth rate (μ), lag phase duration (LPD) and maximum population density (MPD) were determined by fitting the modified Gompertz equation to the M. aeruginosa strain cell count (cells mL⁻¹). A 4.8-fold increase in μ values and a 10.8-fold decrease in the LPD values were found for M. aeruginosa growth when the temperature changed from 15 °C to 35 °C. The activation energy of the specific growth rate (Eμ) and of the adaptation rate (E₁/LPD) were significantly correlated (R² = 0.86). The cardinal temperatures estimated by the modified Ratkowsky model were minimum temperature = 8.58 ± 2.34 °C, maximum temperature = 45.04 ± 1.35 °C and optimum temperature = 33.39 ± 0.55 °C.Maximum MC-LR production decreased 9.5-fold when the temperature was increased from 26 °C to 35 °C. The maximum production values were obtained at 26° C and the maximum depletion rate of intracellular MC-LR was observed at 30–35 °C. The MC-LR cell quota was higher at 26 and 28 °C (83 and 80 fg cell⁻¹, respectively) and the MC-LR Chl-a quota was similar at all the different temperatures (0.5–1.5 fg ng⁻¹).The Gompertz equation and dynamic model were found to be the most appropriate approaches to calculate M. aeruginosa growth and production of MC-LR, respectively. Given that toxin production decreased with increasing temperatures but growth increased, this study demonstrates that growth and toxin production processes are uncoupled in M. aeruginosa. These data and models may be useful to predict M. aeruginosa bloom formation in the environment.     

Human growth hormone-specific aptamer identification using improved oligonucleotide ligand evolution method

LETEG is a method developed and used for the separation and purification of proteins employing a single-step ligand (aptamers) evolution in which aptamers are eluted with an increasing temperature gradient. Using recombinant human growth hormone (rhGH) as the test purification target, and after avoiding cross reactions of aptamers with Bacillus subtilis extracellular proteins by negative SELEX, the effects of time and pH on aptamer binding to rhGH were investigated. The highest binding efficiency of aptamers on rhGH-immobilized microparticles was obtained at pH 7.0. The aptamers that interacted with rhGH were eluted by a multi-stage step-up temperature gradient in ΔT = 10 °C increments within the range T = 55–95 °C; and the strongest affinity binding was disrupted at T = 85 °C where C_Apt = 0.16 μM was eluted. The equilibrium binding data obtained was described by a Langmuir-type isotherm; where the affinity constant was K_D = 218 nM rhGH. RhGH was separated from the fermentation broth with 99.8% purity, indicating that the method developed is properly applicable even for an anionic protein.     

Sources of variation contributing to production and quality attributes of Kyrgyz cashmere in Osh and Naryn provinces: Implications for industry development

We aimed to quantify the sources of variation contributing to the production and quality of cashmere produced in five districts in Osh and Naryn provinces of Kyrgyzstan. In early spring 2008 mid-side cashmere samples were taken from 719 cashmere adult females, and 41 cashmere adult males and castrates. Samples came from 53 villages and a total of 156 farmers’ flocks. For 91 goats from 33 farmers in 13 villages of two districts that had been sampled earlier, cashmere was combed from the goat at the time of a second visit (end of April 2008) when the cashmere would normally be harvested. Following standard cashmere objective measurement, data were examined using general linear modelling to quantify the effects of potential determinants. The mean fibre diameter (MFD) of cashmere differed between provinces (Osh 15.7 μm, Naryn 16.7 μm; P = 4.4 × 10⁻²⁰). About 42% of the cashmere was <16 μm, 48% was 16.0–18.0 μm and 9.5% was >18.0 μm. Most of the cashmere samples were coloured (81%), with 63% black and 19% white. The percentage of cashmere samples that were white declined as MFD increased (26% < 14 μm to 11% of >18 μm). The primary determinants of cashmere MFD of individual goats were age of goat (range 1.46 μm, P = 1.8 × 10⁻¹²) and farm (range 6.5 μm, P = 1.7 × 10⁻¹⁴). The lesser effects detected for sex (range 0.9 μm, P = 0.026) and colour of cashmere (range 1.8 μm, P = 0.023) were based on small sample sizes and are unreliable. Age of goat had important affects on fibre diameter variation (up to 1.7% in coefficient of variation, P = 5.8 × 10⁻⁶) and fibre curvature (2.5–5°/mm, P = 2.1 × 10⁻⁴). By far the greatest effect on fibre curvature was cashmere MFD (P = 3.0 × 10⁻¹⁰⁴) with a smaller effect of sex (about 5°/mm, P = 3.0 × 10⁻⁶). Village effects were detected on fibre diameter variability (range 4.5% in coefficient of variation, P = 0.027) and fibre curvature (range 15°/mm, P = 1.6 × 10⁻⁷). There was a strong negative association between increasing MFD and declining fibre curvature (−5.11 ± 0.181°/mm per 1 μm; P = 7.1 × 10⁻¹²¹; r² = 0.51). Average combed cashmere weight was 164 g, the clean cashmere content was 0.661 and median clean cashmere production was 110 g per goat (range 60–351 g). Combed cashmere production increased with altitude of the village, probably related to different moulting times as spring temperatures warmed up later in higher altitude villages up to 3200 masl. Measurements of combed cashmere MFD were coarser than the mid-side samples taken earlier in the year. There are farmers and cashmere goats in the sampled districts of Kyrgyzstan which produce the finest qualities of commercial cashmere as the vast majority of cashmere is fine, has low variation in fibre diameter and has fibre crimping (curvature) typical of Chinese and Mongolian cashmere. There is substantial scope to increase the production and commercial value of cashmere produced by Kyrgyz goats. In particular, some villages and farmers need to change their buck selection practices if they wish to produce acceptable cashmere. Farmers should separate their finer and white cashmere prior to sale.     

Purification,kinetic and thermodynamic characterization of soluble acid invertase from sugarcane (Saccharum officinarum L.)

We report for the first time kinetic and thermodynamic properties of soluble acid invertase (SAI) of sugarcane (Saccharum officinarum L.) salt sensitive local cultivar CP 77-400 (CP-77). The SAI was purified to apparent homogeneity on FPLC system. The crude enzyme was about 13 fold purified and recovery of SAI was 35%. The invertase was monomeric in nature and its native molecular mass on gel filtration and subunit mass on SDS-PAGE was 28 kDa. SAI was highly acidic having an optimum pH lower than 2. The acidic limb was missing. Proton transfer (donation and receiving) during catalysis was controlled by the basic limb having a pKa of 2.4. Carboxyl groups were involved in proton transfer during catalysis. The kinetic constants for sucrose hydrolysis by SAI were determined to be: k_m = 55 mg ml^?1, k_cat = 21 s^?1, k_cat/k_m = 0.38, while the thermodynamic parameters were: ΔH* = 52.6 kJ mol^?1, ΔG* = 71.2 kJ mol^?1, ΔS* = ?57 J mol^?1 K^?1, ΔG*_E–S = 10.8 kJ mol^?1 and ΔG*_E–T = 2.6 kJ mol^?1. The kinetics and thermodynamics of irreversible thermal denaturation at various temperatures 53–63 °C were also determined. The half -life of SAI at 53 and 63 °C was 112 and 10 min, respectively. At 55 °C, surprisingly the half -life increased to twice that at 53 °C. ΔG*, ΔH* and ΔS* of irreversible thermal stability of SAI at 55 °C were 107.7 kJ mol^?1, 276.04 kJ mol^?1 and 513 J mol^?1K^?1, respectively.     

Long-term decline of brown algal assemblages from southern Brazil under the influence of a nuclear power plant

We investigated long-term trends in brown macroalgal assemblages inhabiting shallow subtidal rocky bottoms under the influence of thermal effluent discharge from the Brazilian nuclear power plant (BNPP). Three operational periods based on the units of the BNPP were analysed: T0 = pre-operational, between the years 1980 and 1983; T1 = operational period of unit 1, between 1988 and 1999; and T2 = operational period of units 1 and 2, between 2005 and 2012. Using generalized linear mixed models (GLMMs), we found significant declines in the numbers of genera and species over time. More than half of the species of brown macroalgae disappeared during T2. In addition, the numbers of macroalgal genera and species were inversely related to the local surface seawater temperatures. Multivariate analyses revealed a clear separation between the years of T2 and those of T0, indicating long-term changes in the community assemblages. Among the most common species in the area, the frequencies of Canistrocarpus cervicornis, Dictyopteris delicatula, Hincksia mitchelliae, Sargassum spp. and Sphacelaria tribuloides decreased during T2, while Padina gymnospora maintained rather high yearly frequencies during T2 (>40%). Our data suggest that seawater temperatures consistently higher than 30 °C together with peaks higher than 35 °C may have triggered the decline in the brown algae on rocky bottoms under the influence of the BNPP discharge. These results from southern Brazil are consistent with studies from other locations that ascribe changes in seaweed diversity to increasing seawater temperatures, highlighting the sensitivity of brown macroalgae to thermal stress and demonstrating their effectiveness as an ecological indicator for monitoring the effects of nuclear power plant effluents on coastal environments.     

Demineralization of crab shell waste by Pseudomonas aeruginosa F722

Crab shell (CS) waste samples (particle size 3–10 and 20–35 mm) were inoculated with the newly isolated Pseudomonas aeruginosa F722 to study the efficiency of microbial demineralization (DM) and deproteinization (DP) in the process of extracting chitin. The inoculated waste was incubated for 7 days at 25, 30 and 35 °C. Various concentrations of glucose were supplemented as carbon source. At the optimal temperature of 30 °C, DM was 92% and DP was 63% DP, whereas the pH dropped from initial pH 8.0 to 4.1. In comparative experiments with different amounts of CS waste, 5% CS waste treatment was shown to be the optimal amount for efficient DM. A positive relationship is correlated between DM and glucose concentration (r² = 0.821), whereas a negative relationship is correlated between DM and pH (r² = 0.793). DP and protease activity were little affected by different crab shell sizes.     

Development of a microfluidic device for determination of cell osmotic behavior and membrane transport properties

An understanding of cell osmotic behavior and membrane transport properties is indispensable for cryobiology research and development of cell-type-specific, optimal cryopreservation conditions. A microfluidic perfusion system is developed here to measure the kinetic changes of cell volume under various extracellular conditions, in order to determine cell osmotic behavior and membrane transport properties. The system is fabricated using soft lithography and is comprised of microfluidic channels and a perfusion chamber for trapping cells. During experiments, rat basophilic leukemia (RBL-1 line) cells were injected into the inlet of the device, allowed to flow downstream, and were trapped within a perfusion chamber. The fluid continues to flow to the outlet due to suction produced by a Hamilton Syringe. Two sets of experiments have been performed: the cells were perfused by (1) hypertonic solutions with different concentrations of non-permeating solutes and (2) solutions containing a permeating cryoprotective agent (CPA), dimethylsulfoxide (Me₂SO), plus non-permeating solute (sodium chloride (NaCl)), respectively. From experiment (1), cell osmotically inactive volume (V_b) and the permeability coefficient of water (L_p) for RBL cells are determined to be 41% [n = 18, correlation coefficient (r²) of 0.903] of original/isotonic volume, and 0.32 ± 0.05 μm/min/atm (n = 8, r² > 0.963), respectively, for room temperature (22 °C). From experiment (2), the permeability coefficient of water (L_p) and of Me₂SO (P_s) for RBL cells are 0.38 ± 0.09 μm/min/atm and (0.49 ± 0.13) × 10⁻³ cm/min (n = 5, r² > 0.86), respectively. We conclude that this device enables us to: (1) readily monitor the changes of extracellular conditions by perfusing single or a group of cells with prepared media; (2) confine cells (or a cell) within a monolayer chamber, which prevents imaging ambiguity, such as cells overlapping or moving out of the focus plane; (3) study individual cell osmotic response and determine cell membrane transport properties; and (4) reduce labor requirements for its disposability and ensure low manufacturing costs.     

Thermal tolerance and preference of exploited turbinid snails near their range limit in a global warming hotspot

Predicted global climate change has prompted numerous studies of thermal tolerances of marine species. The upper thermal tolerance is unknown for most marine species, but will determine their vulnerability to ocean warming. Gastropods in the family Turbinidae are widely harvested for human consumption. To investigate the responses of turbinid snails to future conditions we determined critical thermal maxima (CTMax) and preferred temperatures of Turbo militaris and Lunella undulata from the tropical-temperate overlap region of northern New South Wales, on the Australian east coast. CTMax were determined at two warming rates: 1 °C/30 min and 1 °C/12 h. The number of snails that lost attachment to the tank wall was recorded at each temperature increment. At the faster rate, T. militaris had a significantly higher CTMax (34.0 °C) than L. undulata (32.2 °C). At the slower rate the mean of both species was lower and there was no significant difference between them (29.4 °C for T. militaris and 29.6 °C for L. undulata). This is consistent with differences in thermal inertia possibly allowing animals to tolerate short periods at higher temperatures than is possible during longer exposure times, but other mechanisms are not discounted. The thermoregulatory behaviour of the turban snails was determined in a horizontal thermal gradient. Both species actively sought out particular temperatures along the gradient, suggesting that behavioural responses may be important in ameliorating short-term temperature changes. The preferred temperatures of both species were higher at night (24.0 °C and 26.0 °C) than during the day (22.0 °C and 23.9 °C). As the snails approached their preferred temperature, net hourly displacement decreased. Preferred temperatures were within the average seasonal seawater temperature range in this region. However, with future predicted water temperature trends, the species could experience increased periods of thermal stress, possibly exceeding CTMax and potentially leading to range contractions.     

The carbon flux of global rivers: A re-evaluation of amount and spatial patterns

Global rivers connect three large carbon reservoirs in the world: soil, atmosphere, and ocean. The amount and spatial pattern of riverine carbon flux are essential for the global carbon budget but are still not well understood. Therefore, three linear regression models for riverine DOC (dissolved organic carbon), POC (particulate organic carbon), and DIC (dissolved inorganic carbon) fluxes were established with related generating and transfer factors based on an updated global database. The three models then were applied to simulate the spatial distribution of riverine DOC, POC, and DIC fluxes and to estimate the total global riverine carbon flux. The major conclusions of this study are as follows: the correlation analysis showed that riverine DOC flux is significantly related to discharge (r² = 0.93, n = 109) and soil organic carbon amount (r² = 0.60), POC flux increases with discharge (r² = 0.55, n = 98) and amount of soil erosion (r² = 0.48), and DIC flux is strongly linked to CO₂ consumption by rock weathering (r² = 0.66, n = 111) and discharge (r² = 0.63). In addition, Asia exports more DOC and POC than other continents and North America exports more DIC. The Atlantic Ocean accepts the major portion of riverine DOC, POC, and DIC fluxes of all the oceans. The highest riverine DOC flux occurs in the 0–30°S zone, and the highest riverine POC and DIC fluxes appear in the 30–60°N zone. Furthermore, re-estimation revealed that global rivers export approximately 1.06 Pg C to oceans every year, including 0.24 Pg DOC, 0.24 Pg POC, 0.41 Pg DIC, and 0.17 Pg PIC.     

Temperature-dependent development of Lista haraldusalis (Walker) (Lepidoptera: Pyralidae) on Platycarya strobilacea

The effect of constant temperatures on development and survival of Lista haraldusalis (Walker) (Lepidoptera: Pyralidae), a newly reported insect species used to produce insect tea in Guizhou province (China), was studied in laboratory conditions at seven temperatures (19 °C, 22 °C, 25 °C, 28 °C, 31 °C, 34 °C, and 37 °C) on Platycarya strobilacea. Increasing the temperature from 19 °C to 31 °C led to a significant decrease in the developmental time from egg to adult emergence, and then the total developmental time increased at 34 °C. Egg incubation was the stage where L. haraldusalis experienced the highest mortality at all temperatures. The survival of L. haraldusalis was significantly higher at 25 °C and 28 °C, whereas none of the eggs hatched at 37 °C. Common and Ikemoto linear models were used to describe the relationship between the temperature and the developmental rate for each immature stage of L. haraldusalis. The estimated values of the lower temperature threshold and thermal constant of the total immature stages using Common and Ikemoto linear models were 11.34 °C and 11.20 °C, and 939.85 and 950.41 degree-days, respectively. Seven nonlinear models were used to fit the experimental data to estimate the developmental rate of L. haraldusalis. Based on the biological significance for model evaluation, Ikemoto linear, Logan-6, and SSI were the best models that fitted each immature stage of L. haraldusalis and they were used to estimate the temperature thresholds. These thermal requirements and temperature thresholds are crucial for facilitating the development of factory-based mass rearing of L. haraldusalis.     

Development response of Spodoptera exigua to eight constant temperatures: Linear and nonlinear modeling

Temperature-dependent development of Spodoptera exigua (Hübner) were evaluated at eight constant temperatures of 12, 15, 20, 25, 30, 33, 34 and 36 °C with a variation of 0.5 °C on sugar beet leaves. No development occurred at 12 °C and 36 °C. Total developmental time varied from 120.50 days at 15 °C to 14.50 days at 33 °C. As temperature increased from 15 °C to 33 °C, developmental rate (1/developmental time) of S. exigua increased but declined at 34 °C. The lower temperature threshold (T_min) was estimated to be 12.98 °C and 12.45 °C, and the thermal constant (K) was 294.99 DD and 311.76 DD, using the traditional and Ikemoto–Takai linear models, respectively. The slopes of the Ikemoto–Takai linear model for different immature stages were different, violating the assumption of rate isomorphy. Data were fitted to three nonlinear models to predict the developmental rate and estimate the critical temperatures. The T_min values estimated by Lactin-2 (12.90 °C) and SSI (13.35 °C) were higher than the value estimated by Briere-2 (8.67 °C). The estimated fastest development temperatures (T_fast) by the Briere-2, Lactin-2 and SSI models for overall immature stages development of S. exigua were 33.4 °C, 33.9 °C and 32.4 °C, respectively. The intrinsic optimum temperature (T_Φ) estimated from the SSI model was 28.5 °C, in which the probability of enzyme being in its native state is maximal. The upper temperature threshold (T_max) values estimated by these three nonlinear models varied from 34.00 °C to 34.69 °C. These findings on thermal requirements can be used to predict the occurrence, number of generations and population dynamics of S. exigua.     

Development of electrochemical sulfite biosensor based on SOX/PBNPs/PPY modified Au electrode

A sulfite oxidase (SO_X) (EC 1.8.3.1) purified from Syzygium cumini leaves was immobilized onto Prussian blue nanoparticles/polypyrrole (PBNPs/PPY) nanocomposite film electrodeposited onto the surface of gold (Au) electrode. An electrochemical sulfite biosensor was fabricated using SO_X/PBNPs/PPY/Au electrode as working electrode, Ag/AgCl as standard electrode and Pt wire as auxiliary electrode connected through a potentiostat. The working electrode was characterized by Fourier Transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) at different stages of its construction. The biosensor showed optimum response within 2 s, when operated at 20 mV s⁻¹ in 0.1 M Tris–HCl buffer, pH 8.0 and at 30 °C. Linear range and minimum detection limit were 0.5–1000 μM and 0.1 μM (S/N = 3) respectively. The sensor was evaluated with 95.0% recovery of added sulfite in red wine samples and 1.9% and 3.3% within and between batch coefficients of variation respectively. There was a good correlation (r = 0.96) between red wine samples sulfite value by standard DTNB method and the present method. The sensor was employed for determination of sulfite level in red, white and rose wine samples. The enzyme electrode was used 300 times over a period of 4 months, when stored at 4 °C.