Continuous ethanol production and evaluation of yeast cell lysis and viability loss under very high gravity medium conditions

A combined bioreactor system, composed of a stirred tank and a three-stage tubular bioreactor in series and with a total working volume of 3260 ml, was established. Continuous ethanol production was carried out using Saccharomyces cerevisiae and a very high gravity (VHG) medium containing 280 g l⁻¹ glucose. An average ethanol concentration of 124.6 g l⁻¹ or 15.8% (v) was produced when the bioreactor system was operated at a dilution rate of 0.012 h⁻¹. The yield of ethanol to glucose consumed was calculated to be 0.484 or 94.7% of its theoretical value of 0.511 when ethanol entrapped in the exhaust gas was incorporated. Meanwhile, quasi-steady states and non-steady oscillations were observed for residual glucose, ethanol and biomass concentrations for all of these bioreactors during their operations. Models that can be used to predict yeast cell lysis and viability loss were developed.     

Heligmosomoides polygyrus: inoculum size and glucose, ion, and gas fluxes in the small intestine of mice

Female CDI mice were inoculated with 10, 50, 100, 250, or 500 larvae of Heligmosomoides polygyrus. At Days 7, 9, and 12 after infection, the anterior third of the small intestine was perfused using an in vivo technique. The distribution of worms in the mouse intestine was determined after 7, 9, and 12 days. All worms that were recovered were from the proximal half of the small intestine. When compared to uninfected controls, there was a significant increase (+56%) in glucose absorption of the small intestine at Day 7 after infection with inocula of 50 and 100 larvae; at Day 9, glucose absorption was significantly increased with a 10-larvae inoculum. A decrease in glucose absorption occurred at Days 7 and 9 after infection with a 500-larvae inoculum. Net water absorption was significantly increased (+183%) with the 50- and 100-larvae inocula at Day 7, but was significantly reduced at Day 9 after infection with the 50-, 100-, 250-, and 500-larvae inocula. Both Cl- and Na+ absorption were significantly increased with the 50-, 100-, and 250-larvae inocula at Day 7 after infection; at 9 and 12 days, there was significant net secretion of both ions. In control mice, there was net secretion of K+, while with the 50-, 100-, and 250-larvae inocula on Day 7 there was significant net absorption of K+ ions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synergistic temperature and ethanol effect on<Emphasis Type="Italic"> Saccharomyces cerevisiae</Emphasis> dynamic behaviour in ethanol bio-fuel production

The impact of ethanol and temperature on the dynamic behaviour of Saccharomyces cerevisiae in ethanol biofuel production was studied using an isothermal fed-batch process at five different temperatures. Fermentation parameters and kinetics were quantified. The best performances were found at 30 and 33°C around 120 g l^-1 ethanol produced in 30 h with a slight benefit for growth at 30°C and for ethanol production at 33°C. Glycerol formation, enhanced with increasing temperatures, was coupled with growth for all fermentations; whereas, a decoupling phenomenon occurred at 36 and 39°C pointing out a possible role of glycerol in yeast thermal protection.     

High-density cultivation of Perilla frutescens cell suspensions for anthocyanin production: Effects of sucrose concentration and inoculum size

High-density cultivation of Perilla frutescens cells for anthocyanin production was carried out in both batch and fed-batch modes in a 500-ml shake flask. In fed-batch cultures, a high cell density of 27.7 g dry cells l⁻¹ and a total anthocyanin production of 3.87 g l⁻¹ by intermittent feeding of all medium components except hormones were obtained. In batch cultures, both initial sucrose concentration and inoculum size showed a conspicuous effect on the kinetics of cell growth, sugar consumption, and secondary metabolite (anthocyanins) production by suspended P. frutescens cells. At an inoculum size of 50 g wet cells l⁻¹, the maximum cell density of 38.3 g dry cells l⁻¹ was obtained after 11 days of cultivation at an initial sucrose concentration of 60 g l⁻¹, the highest pigment production of>5.8 g l⁻¹ was attained after 10 days of cultivation at an initial sucrose concentration of 45 g l⁻¹. These amounts of cell mass and anthocyanin pigments were 3.3 and 24 times higher than those at an initial sucrose concentration of 15 g l⁻¹ and inoculum size of 15 g wet cells l⁻¹, respectively.     

Impact of impregnation time and chip size on sugar yield in pretreatment of softwood for ethanol production

Efficient pretreatment is necessary to make the wood-to-ethanol process more feasible. In this study, chips of different sizes were impregnated with SO₂ and steam-pretreated. Dilute-acid pretreatment together with subsequent enzymatic hydrolysis resulted in solubilization of between 69% and 73% of the fermentable sugars (glucose and mannose) in the raw material for the combinations of impregnation times and chip sizes investigated. Shorter impregnation times resulted in slightly lower mannose yields for the larger chips, probably due to poor diffusion of the catalyst. Small differences in glucose yield after enzymatic hydrolysis showed that the overall glucose yield was slightly higher for the smaller chips, however, whether the increased energy demand and cost of size reduction is compensated for by the higher yield, requires techno-economical evaluations.     

Chemical composition and standardized ileal digestibility of crude protein and amino acid in whole yeast and autolyzed yeast derived from sugarcane ethanol production fed to growing pigs

ObjectiveThis research determined the chemical composition and the apparent and standardized ileal digestibility (AID and SID) of crude protein (CP) and amino acids (AA) in whole yeast and autolyzed yeast derived from sugarcane ethanol production fed to growing pigs.MethodsSix growing pigs were randomly allocated in a replicated 3×3 Latin square design with 3 diets and 3 periods of 7 days each, resulting in a total of 6 experimental replications. Three assay diets were formulated using whole yeast, autolyzed yeast, or soybean meal as the sole sources of dietary CP and AA. Pigs were allowed to adapt to the assay diets for 5 days. Thereafter, ileal digesta samples were collected continuously for 8 hours on days 6 and 7.ResultsThere was no difference in the chemical composition between whole yeast and autolyzed yeast, but whole yeast had low digestibility of CP and AA due to the presence of a rigid cell wall. As conducting autolysis can induce cell wall damage, the AID and SID of CP and AA were greater in autolyzed yeast than in whole yeast.ConclusionThe information obtained on the SID of CP and AA in both yeast products can be used for the accurate estimation of the bioavailability of CP and AA in feed formulations. The yeast products derived from sugarcane ethanol production are an alternative protein source in pig diets.     

Ecological correlates of body size in relation to cell size and cell number: patterns in flies, fish, fruits and foliage

Body size is important to most aspects of biology and is also one of the most labile traits. Despite its importance we know remarkably little about the proximate (developmental) factors that determine body size under different circumstances. Here, I review what is known about how cell size and number contribute to phenetic and genetic variation in body size in Drosophila melanogaster, several fish, and fruits and leaves of some angiosperms. Variation in resources influences size primarily through changes in cell number while temperature acts through cell size. The difference in cellular mechanism may also explain the differences in growth trajectories resulting from food and temperature manipulations. There is, however, a poorly recognized interaction between food and temperature effects that needs further study. In addition, flies show a sexual dimorphism in temperature effects with the larger sex responding by changes in cell size and the smaller sex showing changes in both cell size and number. Leaf size is more variable than other organs, but there appears to be a consistent difference between how shade-tolerant and shade-intolerant species respond to light level. The former have larger leaves via cell size under shade, the latter via cell number in light conditions. Genetic differences, primarily from comparisons of D. melanogaster, show similar variation. Direct selection on body size alters cell number only, while temperature selection results in increased cell size and decreased cell number. Population comparisons along latitudinal clines show that larger flies have both larger cells and more cells. Use of these proximate patterns can give clues as to how selection acts in the wild. For example, the latitudinal pattern in D. melanogaster is usually assumed to be due to temperature, but the cellular pattern does not match that seen in laboratory selection at different temperatures.     

The interactive effects of temperature,food level and maternal phenotype on offspring size in Daphnia magna

Invertebrate offspring are usually larger in colder environments. To test for possible effects of covariates (e.g. maternal phenotype and feeding conditions) on this pattern, we performed a laboratory experiment to look at the effect of temperature on newborn weight in the planktonic crustacean Daphnia magna. Three tempèratures (12°C, 16°C and 22°C) and two food levels (10,000 cells ml^–1 and 150,000 cells ml^–1) were used, and offspring were examined from the first five clutches of mothers that had been maintained under the constant experimental conditions for three generations. Preliminary analysis suggested that newborn weight was significantly affected by temperature although patterns in the data were not clear cut. In addition, the covariates mother weight and clutch size were positively and negatively correlated with newborn weight, respectively; and later clutches tended to contain heavier offspring. Therefore, in an effort to control for the effects of the covariates, repeated-measures analysis of covariance was performed using ratio values of newborn weight/mother weight (relative newborn weight) as the dependent variable, clutch size as the covariate and clutch number as the repeated measures term. Now, temperature as a main effect in an ANCOVA model did not significantly influence relative newborn weight. The repeatedmeasure term clutch number also became nonsignificant, indicating that when differences in mother weight due to age were accounted for there were no overall differences in relative newborn weight between clutches from a particular mother. Temperature effects on relative newborn weight were only significant as part of interaction terms with food concentration and with clutch number. Thus there were different weight responses to temperature within food levels, and between clutch numbers within food levels. Under the low-food conditions newborn were heaviest at 16°C, lightest at 12°C and intermediate at 22°C. Conversely, under the high-food condition newborn were lightest at 16°C, heaviest at 12°C and again intermediate at 22°C. However, newborn tended to be heavier under the low food condition, and food concentration was highly significant as a main effect. Mother growth rate showed no significant relationship with newborn weight. It is concluded that direct temperature effects on relative newborn weight are marginal and nonsignificant. Temperature effects through interactions with food concentration and clutch number are important determinants of newborn weight, but relatively speaking account for only a small proportion of observed variance in newborn weight (25%), compared with the direct effect of food concentration (67%).     

不同年际间异子蓬种子大小、萌发能力及结实格局

异子蓬(Borszczowia aralocaspica)为中亚荒漠特有种,在我国仅分布于新疆,其果实具有二型性。对同一生长地2006、2007、2008年异子蓬种子的大小、萌发特性及结实格局进行比较,结果表明:(1)年份和种子类型对种子大小和重量均有显著影响(P<0.05)。(2)2种类型种子具有不同的萌发行为,褐色种子萌发率高(>90%),萌发速度快,而黑色种子萌发率低(2006年的萌发率为31%),萌发速度慢;2种类型种子的萌发指数在不同年际间均差异显著。(3)不同年际间,种子总数、褐色种子数、黑色种子数均具有极显著差异(P<0.001),且随个体的增大黑色种子的比例逐渐减小,褐色种子的比例逐渐增大,并且黑色种子数目均高于褐色种子数目。该研究为深入认识异型种子的生态适应对策提供理论基础。     

Effects of chlorophyll concentration and temperature variation on the reproduction and survival of Temora longicornis (Copepoda, Calanoida) in the Eastern English Channel

The influence of temperature and chlorophyll concentration on egg production, hatching success, female survival and body size of the copepod Temora longicornis was investigated in situ in the coastal waters of the Eastern English Channel. Twenty samples were collected between February and July 2003 three to four times per month. The maximum daily level of egg production of 75.5 eggs female⁻¹ was observed in March, with minima of 10 eggs female⁻¹ in February and July. Between February and March egg production increased with chlorophyll concentration. At the end of March a decrease in egg production corresponded to a strong increase in chlorophyll concentration that indicated a Phaeocystis-dominated bloom. After this period egg production closely followed the temporal variation in chlorophyll concentration with a maximum of 55.3 eggs female⁻¹ in April during a second peak of chlorophyll concentration. Hatching success varied between 60% and 80% and was not influenced by chlorophyll concentration, in situ temperature or any other biological parameter considered in this study. Increases in temperature from February to July paralleled a decrease in body length and an increase in the percentage of spawning females. Mean female survival followed the variation of both temperature and chlorophyll concentration only between April and July. Temperature and chlorophyll concentration affected the reproductive parameters of T. longicornis differently. Female survival and body size were negatively correlated with temperature, while the highest chlorophyll concentrations were not always favourable for egg production. Therefore the quality of food should not be associated with chlorophyll quantity. Furthermore, the maximum values of egg production in this study are the highest recorded for T. longicornis. This study, conducted for the first time in the Eastern English Channel, showed high levels of productivity of T. longicornis despite a decrease of egg production during a Phaeocystis sp. dominated bloom in April.     

Characterization of hybridoma cell responses to elevated pCO(2) and osmolality: intracellular pH, cell size, apoptosis, and metabolism.

CO(2) partial pressure (pCO(2)) in industrial cell culture reactors may reach 150-200 mm Hg, which can significantly inhibit cell growth and recombinant protein production. The inhibitory effects of elevated pCO(2) at constant pH are due to a combination of the increases in pCO(2) and [HCO(-) (3)], per se, and the associated increase in osmolality. To decouple the effects of pCO(2) and osmolality, low-salt basal media have been used to compensate for this associated increase in osmolality. Under control conditions (40 mm Hg-320 mOsm/kg), hybridoma cell growth and metabolism was similar in DMEM:F12 with 2% fetal bovine serum and serum-free HB GRO. In both media, pCO(2) and osmolality made dose-dependent contributions to the inhibition of hybridoma cell growth and synergized to more extensively inhibit growth when combined. Elevated osmolality was associated with increased apoptosis. In contrast, elevated pCO(2) did not increase apoptotic cell death. Specific antibody production also increased with osmolality although not with pCO(2). In an effort to understand the mechanisms through which elevated pCO(2) and osmolality affect hybridoma cells, glucose metabolism, glutamine metabolism, intracellular pH (pHi), and cell size were monitored in batch cultures. Elevated pCO(2) (with or without osmolality compensation) inhibited glycolysis in a dose-dependent fashion in both media. Osmolality had little effect on glycolysis. On the other hand, elevated pCO(2) alone had no effect on glutamine metabolism, whereas elevated osmolality increased glutamine uptake. Hybridoma mean pHi was approximately 0.2 pH units lower than control at 140 mm Hg pCO(2) (with or without osmolality compensation) but further increases in pCO(2) did not further decrease pHi. Osmolality had little effect on pHi. Cell size was smaller than control at elevated pCO(2) at 320 mOsm/kg, and greater than control in hyperosmotic conditions at 40 mm Hg.     

Influence of seawater temperature on growth bands, mineralogy and carbonate production in a bioconstructional bryozoan

The cheilostome bryozoan Pentapora, an important benthic carbonate producer on non-tropical continental shelves, displays seasonal variations in deposition of the calcareous skeleton reflected by ‘winter’ and ‘summer’ growth bands. Studies on colonies from Atlantic and Mediterranean localities show that the ratio of the heights of these growth bands correlates significantly with mean annual range of temperature (MART) and mean annual temperature (MAT). The locality with the lowest MART and MAT showed the greatest wt% of calcite in the winter growth band. The opposite was true for the locality with the highest MART and MAT. Carbonate standing stock and carbonate production estimated for Atlantic localities were an order of magnitude lower than those measured at Mediterranean localities. Variability in skeletal carbonate depositional pattern and mineralogy suggests that fossil and historical collections of Pentapora may be useful indicators of past thermal conditions.     

Acclimation and activity of ammonia-oxidizing bacteria with respect to variations in zinc concentration, temperature, and microbial population

Activity of ammonia-oxidizing bacteria (AOB) to simultaneous variation in Zn²⁺ concentration (0.01-3.5 mg/L), temperature (23-33 °C), and AOB concentration (3-30 × 10⁶ gene copies/mL) in a steel industry wastewater treatment plant was evaluated. Two equations were developed to describe the lag period (i.e., AOB acclimation) and ammonia oxidation rate (i.e., growth of the AOB) depending on the variables. AOB concentration and temperature both had significant effects on lag period and the ammonia oxidation rate. Zn²⁺ concentration only had a significant effect on ammonia oxidation rate at 5% α-level. There was a significant interaction between AOB concentration and temperature for both lag period and ammonia oxidation rate. The effects of the variables were not significant when AOB concentration was higher than 2.0 × 10⁷ copies/mL. There was no visible shift or changes in AOB communities based on DGGE analysis with amoA gene primers.     

Effect of sensitivity to abscisic acid on scaling relationships for biomass production rates and body size in Arabidopsis thaliana

The allometric relationships for plant daily biomass production rates, different measures of body size (dry weight and length) and photosynthetic biomass per plant are reported for two mutants of Arabidopsis thaliana (abi1-1, insensitive to ABA; era1-2, hypersensitive to ABA). Scaling relationships, such as daily rate of growth (G) vs body mass (M), plant body length or plant height (L) vs body mass (M), photosynthetic biomass (M _p ) vs non-photosynthetic biomass (M _n ), and daily rate of growth (G) vs. photosynthetic biomass (M _p ) were significantly different in abi1-1 and era1-2. It is implied that the sensitivity to abscisic acid may change the scaling relationships for plant biomass production rate and body size in Arabidopsis thaliana. Because these scaling relationships are closely related to sensitivity to abscisic acid, they are of importance for phytohormonal ecology.     

The combined influence of sub-optimal temperature and salinity on the in vitro viability of Perkinsus marinus, a protistan parasite of the eastern oyster Crassostrea virginica

Perkinsus marinus is a major cause of mortality in eastern oysters along the Gulf of Mexico and Atlantic coasts. It is also well documented that temperature and salinity are the primary environmental factors affecting P. marinus viability and proliferation. However, little is known about the effects of combined sub-optimal temperatures and salinities on P. marinus viability. This in vitro study examined those effects by acclimating P. marinus at three salinities (7, 15, 25 ppt) to 10 °C to represent the lowest temperatures generally reached in the Gulf of Mexico, and to 2 °C to represent the lowest temperatures reached along the mid-Atlantic coasts and by measuring changes in cell viability and density on days 1, 30, 60 and 90 following acclimation. Cell viability and density were also measured in 7 ppt cultures acclimated to each temperature and then transferred to 3.5 ppt. The largest decreases in cell viability occurred only with combined low temperature and salinity, indicating that there is clearly a synergistic effect. The largest decreases in cell viability occurred only with both low temperature and salinity after 30 days (3.5 ppt, 2 °C: 0% viability), 60 days (3.5 ppt, 10 °C: 0% viability) and 90 days (7 ppt, 2 °C: 0.6 ± 0.7%; 7 ppt, 10 °C: 0.2 ± 0.2%).     

黑莓对水分、盐分和低温逆境的适应性

在南京盆栽条件下,黑莓（Rubus L.spp.)“Hull”品种1年生扦插苗在土壤相对含水量为70%以上时,地上部分和地下部分均生长良好,正常开花结实;土壤相对含水量下降到50%-60%时,地上部分生长明显减弱,地下部分生长受到一定影响,但植株都能存活;土壤相对含水量下降到45%-50%时,地上部分及地下部分均生长不良,部分植株死亡;土壤相对含水量降到30%-35%时,植株无法生存。黑莓“Hull”品种扦插苗是对盐（NaCl)敏感的植物,中度（0.2%)以上盐浓度对生长有明显的抑制作用,相对于地上部分和根系,根颈部所受的影响较小,表现为地上部无新的枝条萌出,无叶片产生;地下部无新根产生;根颈部萌芽数量减少,长度变小,随着盐浓度的增加,生长减慢甚至死亡。轻度（0.1%)盐处理未见有抑制作用。黑莓不同品种的枝条抗冻性不同,所测定的3个品种中,“HuLL”抗冻性最差,LT50为-25.5℃,“Chester”与“Navoho”的抗冻性相近,LT50均为-29℃。     

Production of male flowers does not decrease with plant size in insect‐pollinated Sagittaria trifolia,contrary to predictions of size‐dependent sex allocation

Abstract It has been proposed that relative allocation to female function increases with plant size in animal‐pollinated species. Previous investigations in several monoecious Sagittaria species seem to run contrary to the prediction of size‐dependent sex allocation (SDS), throwing doubt on the generalization of SDS. Plant size, phenotypic gender, and flower production were measured in experimental populations of an aquatic, insect‐pollinated herb Sagittaria trifolia (Alismataceae) under highly different densities. The comparison of ramets produced clonally can reduce confounding effects from genetic and environmental factors. In the high‐density population, 48% of ramets were male without female flowers, but in the low‐density population all ramets were monoecious. We observed allometric growth in reproductive allocation with ramet size, as evident in biomass of reproductive structures and number of flowers. However, within both populations female and male flower production were isometric with ramet size, in contrast to an allometric growth in femaleness as predicted by SDS. Phenotypic gender was not related to ramet size in either population. The results indicated that large plants may increase both female and male function even in animal‐pollinated plants, pointing towards further studies to test the hypothesis of size‐dependent sex allocation using different allocation currencies.     

Mutation of RGG2, which encodes a type B heterotrimeric G protein γ subunit,increases grain size and yield production in rice

Heterotrimeric G proteins, which consist of G_α, G_β and G_γ subunits, function as molecular switches that regulate a wide range of developmental processes in plants. In this study, we characterised the function of rice RGG2, which encodes a type B G_γ subunit, in regulating grain size and yield production. The expression levels of RGG2 were significantly higher than those of other rice G_γ‐encoding genes in all tissues tested, suggesting that RGG2 plays essential roles in rice growth and development. By regulating cell expansion, overexpression of RGG2 in Nipponbare (NIP) led to reduced plant height and decreased grain size. By contrast, two mutants generated by the clustered, regularly interspaced, short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9) system in the Zhenshan 97 (ZS97) background, zrgg2‐1 and zrgg2‐2, exhibited enhanced growth, including elongated internodes, increased 1000‐grain weight and plant biomass and enhanced grain yield per plant (+11.8% and 16.0%, respectively). These results demonstrate that RGG2 acts as a negative regulator of plant growth and organ size in rice. By measuring the length of the second leaf sheath after gibberellin (GA₃) treatment and the GA‐induced α‐amylase activity of seeds, we found that RGG2 is also involved in GA signalling. In summary, we propose that RGG2 may regulate grain and organ size via the GA pathway and that manipulation of RGG2 may provide a novel strategy for rice grain yield enhancement.     

Light, temperature and nutrients as factors in photosynthetic adjustment to an elevated concentration of carbon dioxide

The short-term stimulation of the net rate of carbon dioxide exchange of leaves by elevated concentrations of CO₂ usually observed in C₃ plants sometimes does not persist. Experiments were conducted to test whether the patterns of response to the environment during growth were consistent with the hypotheses that photosynthetic adjustment to elevated CO₂ concentration is due to (1) feedback inhibition or (2) nutrient stress. Soybean [Glycine max (L.) Merr. cv. Williams] and sugar beet (Best vulgaris L. cv. Mono Hye-4) were grown from seed at 350 and 700 μl^? CO₂, at 20 and 25°C, at a photon flux density of 0.5 and 1.0 mmol m^?2 S^?1 and with three nutrient regimes until the third trifoliolate leaf of soybean or the sixth leaf of sugar beet had finished expanding. Net rates of CO₂ exchange of the most recently expanded leaves were then measured at both 350 and 700 μl 1^?1 CO₂. Plants grown at the elevated CO₂ concentration had net rates of leaf CO₂ exchange which were reduced by 33% in sugar beet and 23% in soybean when measured at 350 μl 1^?1 CO₂ and when averaged over all treatments. Negative photosynthetic adjustment to elevated CO₂ concentration was not greater at 20 than at 25°C, was not greater at a photon flux density of 1.0 than at 0.5 mmol m^?2 S^?1 and was not greater with limiting nutrients. Furthermore, in soybean, negative photosynthetic adjustment could be induced by a single night at elevated CO₂ concentration, with net rates of CO₂ exchange the next day equal to those of leaves of plants grown from seed at the elevated concentration of CO₂. These patterns do not support either the feedback-inhibition or the nutrient-stress hypothesis of photosynthetic adjustment to elevated concentrations of CO₂.