Differences In Physiological State Research Articles

Extraction of soluble proteins by bead milling from Tetraselmis chui in two different physiological states

Tetraselmis is an interesting microalga for food products because of its high protein content and surface productivity as well as the possibility to scale up the culture easily. However, this specie is yet understudied compared to other algae such as Chlorella. Different batches of Tetraselmis chui were received from the same supplier, with different morphological properties, probably associated with a difference in physiological state: one batch contained circular and dividing cells and the other flagellated cells. The batches were characterized biochemically in terms of protein, carbohydrate and ash content and the rupturability was tested to characterize their behavior to cell disruption. One batch was found way more fragile than the other. The bead milling of the two batches showed also striking differences in terms of cell disruption kinetic, as well as dry matter repartition after centrifugation and protein recovery yields within the supernatant. Nearly no differences in protein yield were observed after bead milling in comparison to freeze-thawing for the resistant batch, with a final yield of 11 % of the initial proteins. However, a clear protein release was observed for the fragile batch along the milling residence time, with a final protein yield of 32 %. The protein released were characterized by SDS PAGE and zymography and differences were observed, confirming the difference in metabolism. Several physicochemical modifications were applied to the cell lysate to increase the yields using pH, temperature and dilution. This latest modification was the most promising. The results underlined that a difference in physiological state of Tetraselmis chui had a significant impact on the following biorefinery, affecting directly the cell disruption and the protein recovery yields. The valorization of the whole microalgae thus necessitates the finest coupling between upstream and downstream.

Сезонная динамика содержания компонентов антиокислительной системы хвои сосны обыкновенной (Pinus sylvestris L.) в зоне локального теплового воздействия

The seasonal changes in a period of low temperatures and characteristic correlations of some antioxidant system (AOS) components in pine needles influenced by a gas flare are investigated in this study. The parameters taken are total water content (TWC) in needles, peroxidase activity (AP) and selected elements of the antioxidant system of needles, such as content of carotenoids (Car), ascorbic acid (AA), catechins (Cat) and flavanols (Fl). The needles come from Scots pine trees (Pinus sylvestris L.), which grow in a gradient of environmental conditions formed in the zone of thermal field of the gas flare impact (at various distances). The gas flare is situated on the territory of the Khanty-Mansiysk Autonomous Okrug (UGRA) of Russia. Three hypotheses were subject to verification: 1) the thermal field of the gas flare during the low temperature period affects the water exchange and the AOS state of needles; 2) increase in temperature of the environment in the flare impact zone during the autumn-winter period causes the decrease in amount of moisture in needles, which is a trait of oxidative stress in cells; 3) in the functioning of а needle’s AOS, there are correlations between its components, which values depend on distance from the gas flare and environment created by it. It was found that in the thermal field gradient of the flare, there is neither an additional reduction in TWC in needles compared to the background nor signs of change in the state of AOS corresponding to the oxidative stress in the cells. The greatest impact of the gas flare on characteristics of the physiological state of pine needles is observed in the section closest to the flare. It reveals in the higher values of AP, TWC, Car and decrease in concentration of Fl and AA. The seasonal dynamics of the studied traits values do not correlate with the temperature of the environment. It indicates the indirect effect on the regulation of needle’s AOS activity. The factor and correlation analysis of the data indicate a difference in physiological state of pine needles at different distances from the flare. There is no domination of any processes in the functioning of AOS components. The observed correlations between the studied properties change according to distance to the flare. The most stable is a negative AP relationship with ofter parameters, which rise with the increased distance from the flare. The consistency degree of separate AOS components functioning is maximal in background conditions and decreases when approaching the flare. This fact is explained by the modifying effect of the flare on physiological and biochemical processes of the needle’s adaptation to specific climatic conditions of the environment. For citation: Shavnin S.A., Yusupov I.A., Montile A.A., Golikov D.Yu., Marina N.V. Seasonal Dynamics of Content of Antioxidant System Components in Needles of Scots Pine (Pinus sylvestris L.) Trees Situated in the Local Warming Impact Zone. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 2, pp. 38–57. (In Russ.). https://doi.org/10.37482/0536-1036-2023-2-38-57

Plasma protein binding and tissue retention kinetics influence the rate and extent of nicotine delivery to the brain

Nicotine from inhaled combustible cigarette smoke is delivered rapidly to the brain, and sufficient unbound nicotine concentrations exert pharmacological effects. In addition to nicotine, combustible cigarette smoke also contains a significant number of toxicants that trigger perturbations, leading to an altered steady state due to differential expression of proteins. In this study, a physiologically based pharmacokinetic (PBPK) model for inhaled nicotine was used to simulate the influence of lysosomal change-driven tissue retention and plasma protein binding levels on nicotine pharmacokinetics (PK). A 3 × increase in tissue lysosomal volumes lowered the nicotine brain maximum concentration (Cmax) by 20.8%. Similarly, a 50% increase in plasma protein binding also lowered the unbound plasma arterial nicotine Cmax by 39.4%. Such fundamental changes in nicotine disposition due to physiological changes in combustible cigarette smokers will lead to altered nicotine consumption and exposure-responses of other weakly basic drugs. Literature reports indicate that nicotine consumed from non-combustible products do not alter drug exposures, indicating fewer or less severe toxicant-driven perturbations with the use of these products. Although several other parameters influence nicotine PK, this PBPK modeling study shows that increased tissue retention and plasma protein binding reduce nicotine delivery to the brain and could lead to differential consumption of combustible cigarettes. These differences in physiological states among combustible cigarette smokers need to be evaluated and should be considered during therapeutic interventions.

Normalized mutual information of fNIRS signals as a measure for accessing typical and atypical brain activity.

Normalized mutual information (NMI) can be used to detect statistical correlations between time series. We showed possibility of using NMI to quantify synchronicity of information transmission in different brain regions, thus to characterize functional connections, and ultimately analyze differences in physiological states of brain. Resting-state brain signals were recorded from bilateral temporal lobes by functional near-infrared spectroscopy (fNIRS) in 19 young healthy (YH) adults, 25 children with autism spectrum disorder (ASD), and 22 children with typical development (TD). Using NMI of the fNIRS signals, common information volume was assessed for each of three groups. Results showed that mutual information of children with ASD was significantly smaller than that of TD children, while mutual information of YH adults was slightly larger than that of TD children. This study may suggest that NMI could be a measure for assessing brain activity with different development states.

Early social experience has life-long effects on baseline but not stress-induced cortisol levels in a cooperatively breeding fish

In cooperatively breeding cichlid fish, the early social environment has lifelong effects on the offspring's behaviour, life-history trajectories and brain gene expression. Here, we asked whether the presence or absence of parents and subordinate helpers during early life also shapes fluctuating levels of cortisol, the major stress hormone in the cichlid Neolamprologus pulcher. To non-invasively characterize baseline and stress-induced cortisol levels, we adapted the ‘static’ holding-water method often used to collect waterborne steroid hormones in aquatic organisms by including a flow-through system allowing for repeated sampling without handling of the experimental subjects. We used 8-year-old N. pulcher either raised with (+F) or without (−F) parents and helpers in early life. We found that N. pulcher have a peak of their circadian cortisol cycle in the early morning, and that they habituated to the experimental procedure after four days. Therefore, we sampled the experimental fish in the afternoon after four days of habituation. −F fish had significantly lower baseline cortisol levels, whereas stress-induced cortisol levels did not differ between treatments. Thus, we show that the early social environment has life-long effects on aspects of the physiological stress system of the Hypothalamic-Pituitary-Interrenal (HPI) axis. We discuss how these differences in physiological state may have contributed to the specialization in different social and life-history trajectories of this species.

Understanding blood and serum values of the agouti (Dasyprocta spp.): A rodent of the Neotropics with the potential to be domesticated

This short communication is intended to provide information on the blood and serum biochemical parameters of the agouti ( Dasyprocta spp.). Information on blood and serum biochemical parameters of this neo-tropical rodent is very scarce. Three agouti species from the Neotropical region were included in this report: Dasyprocta leporina , Dasyprocta fuliginosa and Dasyprocta prymnolopha . Several blood parameters were similar irrespective of the species, location, physiological state and method of restraint when blood was collected. Some of these parameters were red blood cell count, haemoglobin, haematocrit and mean corpuscular volume. Differences seen in some parameters were attributed to the differences in physiological state or environmental impact on the animal. The literature that was available showed a large time gap of approximately thirty (30) years in the reporting of blood parameters in the agouti. Early work was done in the mid-1970s and then recommenced in the mid-2000s. Some biochemical parameters such as triglycerides, amylase, chloride, sodium, potassium, bilirubin and uric acid were only recorded in the literature once and comparison of values was impossible. These parameters require further investigation which can be done in future studies. The dearth of information on the blood profile of the agouti gives justification for further research to be done in this regard as well as more detailed analysis of the effects that the environment and physiological states may have on haematological and biochemical parameters.

How growth conditions of Euglena gracilis cells influence cellular composition as evidenced by Fourier transform infrared spectroscopy and direct infusion high-resolution mass spectrometry

This study aims to assess the influence of growth and culture conditions of the Euglena gracilis protist on the cellular chemical composition. Fourier transform infrared spectroscopy (FT-IR) and direct infusion Orbitrap electrospray ionization mass spectrometry (ESI-MS) were used in tandem for confirmation of functional groups, and to decipher the normalized percentage abundances of compound classes, molecular species, and aromaticity and oxygenation within each growth condition. Abundances of molecular species and compound classes varied with growth and culture conditions. No major differences in the qualitative FT-IR-based screening of functional groups were found between growth conditions. This contrasts with ESI-MS-based results where polyphenols, carbohydrate, and condensed aromatic compounds were the most abundant in dark-grown conditions with glucose supplementation, revealing the differences in physiological states of the cell in different growth conditions. Dark-grown conditions promoted CHO molecular species while light-grown conditions favored CHON, CHOS, and CHONS molecular species. The dark-grown exponential E. gracilis cells grown in glucose-supplemented media showed the greatest normalized abundances of aromatics, carbohydrate, polyphenols, and protein, which are compound classes typically involved in metal binding.

Insights into Bacterial Milk Spoilage with Particular Emphasis on the Roles of Heat-Stable Enzymes, Biofilms, and Quorum Sensing

Milk spoilage caused by psychrotrophic bacteria and their heat-stable enzymes is a serious challenge for the dairy industry. In many studies, spoilage has been explored based on the simplistic view of undesirable enzymes produced by planktonic cells. Recently, biofilms and quorum sensing (QS) have been suggested as important factors in the deterioration of milk, which opens new avenues for investigation of the processes and challenges. Production and heat stability of enzymes are enhanced in biofilms, mainly because of inherent differences in physiological states and protective shielding by extracellular polymeric substances. QS plays a key role in modulating expression of hydrolytic enzymes and biofilm formation. To date, few studies have been conducted to investigate the complex interplays of enzyme production, biofilm formation, and QS. This review provides novel insights into milk spoilage with particular emphasis on the roles of biofilms and QS and summarizes potential effective strategies for controlling the spoilage of milk.

More than morphology: Differences in food ration drive physiological plasticity in echinoid larvae

Previous studies examining echinoid larval development have observed food-dependent allometric growth in morphological features related to particle capture ability. The aim of the current study was to determine if in conjunction with this morphological plasticity, there was also evidence for physiological plasticity (i.e., food-dependent differences in mass-specific rates and/or energetic efficiencies). Larvae of the Pacific sand dollar, Dendraster excentricus, were fed relatively low and high amounts of algae (1,000 and 10,000algalcellsml−1, respectively). Morphological plasticity was observed, with low-fed larvae possessing longer ciliated bands and postoral arms relative to midline body length and stomach length. Rates of ingestion, metabolism, and growth (protein and lipid biomass) were measured throughout larval development to investigate differences in larval energy partitioning and growth efficiencies. Mass-specific rates of ingestion and respiration were ~2-fold higher in high-fed larvae, indicative of significant differences in physiological state. While total energy ingested reflected the 10-fold difference in feeding concentration, partitioning of energy between growth and metabolism was significantly different. Low-fed larvae possessed higher ingestion-related efficiencies (assimilation, gross growth, and protein growth efficiencies) that decreased with age. High-fed larvae exhibited consistently greater values of net growth efficiency throughout development. This increase was driven by increasing metabolic efficiency of protein deposition. A correlative analysis between rates of ingestion and metabolism demonstrated that both low- and high-fed larvae had a similar cost of feeding of 0.29 (±0.01; SE) μJ (algal cell ingested)−1. These results demonstrate that larval responses to food levels are not just morphologically plastic, but also physiologically plastic. It is important to further understand these mechanisms of physiological plasticity and their potential link to morphology. Such information will result in a more comprehensive understanding of larval growth and factors that influence recruitment success.

Sexual Dimorphism, Age, and Fat Mass Are Key Phenotypic Drivers of Proteomic Signatures.

Validated protein biomarkers are needed for assessing health trajectories, predicting and subclassifying disease, and optimizing diagnostic and therapeutic clinical decision-making. The sensitivity, specificity, accuracy, and precision of single or combinations of protein biomarkers may be altered by differences in physiological states limiting the ability to translate research results to clinically useful diagnostic tests. Aptamer based affinity assays were used to test whether low abundant serum proteins differed based on age, sex, and fat mass in a healthy population of 94 males and 102 females from the MECHE cohort. The findings were replicated in 217 healthy male and 377 healthy female participants in the DiOGenes consortium. Of the 1129 proteins in the panel, 141, 51, and 112 proteins (adjusted p < 0.1) were identified in the MECHE cohort and significantly replicated in DiOGenes for sexual dimorphism, age, and fat mass, respectively. Pathway analysis classified a subset of proteins from the 3 phenotypes to the complement and coagulation cascades pathways and to immune and coagulation processes. These results demonstrated that specific proteins were statistically associated with dichotomous (male vs female) and continuous phenotypes (age, fat mass), which may influence the identification and use of biomarkers of clinical utility for health diagnosis and therapeutic strategies.

Life in the sea of plenty: Seasonal and regional comparison of physiological performance of Euphausia hanseni in the northern Benguela upwelling system

Variability in upwelling events may lead to periods of constrained food availability in the northern Benguela upwelling system (NBUS), thereby affecting the physiological state and metabolic activity of euphausiids. Most attention has so far been paid to seasonal effects but little is known about regional variability. Metabolic activity (expressed by respiration and excretion rates) and physiological state (expressed by reproductive effort and moult activity) in Euphausia hanseni were examined at different stations during austral summer (minimum upwelling) and austral winter (maximum upwelling). Overall, regional differences in physiological state, influencing metabolic activity, were greater than seasonal ones, indicating favourable conditions for growth and reproduction year-round. Higher respiration rates were found for females in more advanced stages of sexual development. Moult stage did not affect oxygen consumption rates, however. The physiological state of E. hanseni at the time of capture may serve as a meaningful indicator of the associated hydrographic conditions in the NBUS, to be further used in eco-system analysis on seasonal or long-term time scales. A latitudinal comparison of species highlights the extraordinary physiological plasticity of euphausiids.

Sources of intraspecific variation in sleep behaviour of wild great tits

Ecologists have recently begun to recognize sleep as a behaviour that is important in animal ecology. The first steps have been taken to characterize sleep in free-living birds, but it is unclear to what extent these results can be generalized between species. To describe sleep behaviour in the wild, we videorecorded great tits, Parus major, in their roosting boxes during two consecutive winters and individuals in captivity for comparison. Here, we examined endogenous and exogenous correlates of sleep behaviour in free-living great tits and addressed the potential confounding issues of studying avian sleep in captivity. Like that in blue tits, Cyanistes caeruleus, sleep behaviour in great tits was strongly related to season, and was affected by sex, age and the environment. Although literature suggests relationships between sleep and risk-taking behaviours, possibly arising from stable differences in physiological state, sleep behaviour appeared to be plastic in great tits, and was not predicted by between-individual variation in exploratory tendencies. Captive tits initiated sleep later than wild individuals, even under natural photoperiodic conditions, suggesting that captivity alters timing and duration of sleep in great tits. Long-term repeatability in sleep behaviour was low for all variables, except morning latency (high repeatability) and evening box entry time, evening latency and frequency of awakenings (no detectable repeatability). Variation in sleep behaviour may largely represent within-individual differences in daily sleep requirements. Our study describes how different observable components of sleep are intercorrelated by providing evidence for significant within-individual correlations between sleep behaviours, which represent the integration of plasticity between traits. Consistent with low repeatability, low between-individual correlations suggest substantial behavioural plasticity in sleep, rather than a correlational structure leading to clear sleep ‘syndromes’. Our study provides quantitative evidence for the factors producing phenotypic plasticity in behavioural sleep in an ecological context.

Fitness, physical activity and BMI in 5- to 6-year-old children; cross-sectional analysis on a sub-sample of children from the WAVES study, UK

Eating in the Absence of Hunger (EAH) is a behavioural trait referring to children’s susceptibility to eating when sated, in response to the presence of palatable snack foods. No study has yet examined whether television (TV) food advertising may provoke EAH behaviours in children. Research has found that exposure to TV food advertising increases food intake in children and that this increase is largest in the obese and thosewith higher habitual exposure to TV adverts. Therefore, this study aims to investigate the effects of TV food adverts in relation to differences in physiological state to observe EAH differences in children. Using a mixed-measures designwith one between-subjects factor (physiological state; hungry or sated) and one within-subjects factor (advert condition; food or non-food), 110 children aged 7–11 were tested on two occasions. Participants were exposed to each of the two types of adverts (in a counterbalanced order) before being given the opportunity to eat ad libitum from a selection of snacks. Height and weight measurements were taken and parental measures of habitual TV exposure collected. Preliminary data show a trend towards significance for increased consumption in the sated group after food advert exposure compared with toy adverts (10 kcal increase; p = 0.407). Sated overweight/obese children showed a significant increase in food consumption after watching TV food adverts compared with toy adverts (25 g increase; p = 0.048). This study may demonstrate that TV adverts serve as food cues triggering consumption in children who are already satisfied.

Relative quantification of beta-casein expression in primary goat mammary epithelial cell lines.

Primary mammary epithelial cell cultures were established from mammary tissue of lactating and non-lactating goats to assess the expression of beta-casein (CSN2) in vitro. Primary cell cultures were established by enzymatic digestion of mammary tissue and characterized using antibodies against cytokeratin 14, cytokeratin 18, and vimentin. The established primary cell lines in the second passage were grown in basal medium on plastic and in hormone-supplemented (lactogenic) medium on plastic and on an extracellular matrix-covered surface, respectively. CSN2 gene expression was evaluated using quantitative reverse transcription PCR. The presence of CSN2 transcripts was detected in all samples, including cells originating from non-lactating goat, grown in basal medium. The presence of CSN2 protein was confirmed using immunofluorescence. Response to the hormonal treatment and cell morphology differed between the cell lines and treatments. In 2 cell lines supplemented with lactogenic hormones in the medium, CSN2 expression was increased, while CSN2 levels in one of the cell lines remained constant, regardless of the treatment. Addition of extracellular matrix showed positive effects on CSN2 transcription activity in 1 of the cell lines, while in the other 2 showed no statistically significant effects. CSN2 expression appeared to depend on subtle differences in physiological state of the starting tissue material, growth conditions, cell types present in the culture, and methods used for cell culture establishment. Further studies are necessary to identify factors that determine hormone-responsiveness and transcriptional activity of milk protein genes in goat primary mammary cell cultures.

Habitat Quality Affects Early Physiology and Subsequent Neuromotor Development of Juvenile Black-Capped Chickadees

In songbirds, the ability to learn and render the species-specific song is influenced by the development of both the song nuclei in the brain and the syrinx (bird's vocal apparatus) early in the bird's life. In black-capped chickadees (Poecille atricapillus), habitat quality is known to affect song structure, with birds in high-quality habitat (mature forest) having a higher song consistency than birds in low-quality habitat (young forest). Although this difference is suspected to stem from differences in development, the developmental status of juvenile birds in either habitat remains unexplored. In this study, we used ptilochronology and feather corticosterone to compare the conditional state of juvenile chickadees in young and mature forest during two distinct periods of song learning - the sensory phase, which occurs prior to settlement, and the sensorimotor phase, which occurs post-settlement. A sample of juvenile males was captured and euthanized several weeks prior to their first breeding season to compare the development of song center nuclei and syrinx in both habitats. The corticosterone levels of natally-grown feathers were greater among birds that settled in mature than young forests - as these feathers were grown pre-settlement, they reflect differences in physiology during the sensory phase. This difference in conditional state is reflected by differences in syrinx and song center nuclei development later during the sensorimotor phase - birds in young forest have smaller syrinx, and moderately-larger RA, than birds in mature forest. Those differences could be responsible for the difference in consistency in song structure observed across habitats. The difference in physiological state across habitats, combined with potential compounding effect of differences in winter resources between habitats, could influence the difference in syrinx and neural development seen in juvenile males during the early spring, and influence the male's ability to learn and render their species-specific song.

Vitamin E supplementation during the dry period in dairy cattle. Part II: Oxidative stress following vitamin E supplementation may increase clinical mastitis incidence postpartum

The aim of this study was to evaluate, retrospectively, which physiological states influenced the effect of vitamin E supplements during the dry period on the level of oxidative stress at 2 wk antepartum. Furthermore the effect of oxidative stress at 2 wk antepartum on the risk of clinical mastitis in early lactation was investigated. Cows experience oxidative stress around calving. Vitamin E is able to decrease oxidative stress by scavenging free radicals. Normally, vitamin E radicals formed when vitamin E reacts with free radicals are regenerated by a network of other antioxidants, termed the “vitamin E regeneration system” (VERS). In case of vitamin E supplementation, VERS should be sufficient to regenerate formed vitamin E radicals; if not, oxidative stress might increase instead of decrease. Additionally, the level of oxidative stress and vitamin E might be important physiological states to evaluate before supplementation. In a clinical trial, 296 cows on 5 farms were randomly divided into 2 groups, supplemented with a mineral mix between dry off and calving that supplied 3,000 or 135 IU/d, respectively. Blood samples collected at dry off and 2 wk antepartum were analyzed for vitamin E, reactive oxygen metabolites, ferric-reducing ability of plasma, glutathione peroxidase, and malondialdehyde. Cows were allocated retrospectively into 8 subgroups based on the level of oxidative stress, vitamin E, and VERS status at dry off. To evaluate whether differences in physiological states at dry off influenced the effect of vitamin E supplementation on the level of oxidative stress, group effects (supplemented vs. control) were studied with Student's t-test for all 8 subgroup at 2 wk antepartum. Differences in physiological states at dry off influenced the effect of vitamin E supplements. In 2 insufficient VERS subgroups, the supplemented group had higher levels of free radicals at 2 wk antepartum compared with the control group. Relative risk calculation was used to study the effect of oxidative stress at 2 wk antepartum on the incidence of mastitis in the first 100 d of lactation. Higher levels of oxidative stress at 2 wk antepartum were related to higher risk of clinical mastitis. In conclusion, not every dry cow responded well to high vitamin E supplementation. This subgroup analysis provides a possible explanation for the unexpected adverse effects observed in the clinical trial.

On the role of metabolic activity on the transport und deposition of Pseudomonas fluorescens in saturated porous media

A study was conducted to understand the role of cell concentration and metabolic state in the transport and deposition behaviour of Pseudomonas fluorescens with and without substrate addition. Column experiments using the short-pulse technique (pulse was equivalent to 0.028 pore volume) were performed in quartz sand operating under saturated conditions. For comparison, experiments with microspheres and inactive (killed) bacteria were also conducted. The effluent concentrations, the retained particle concentrations and the cell shape were determined by fluorescent microscopy. For the transport of metabolically-active P. fluorescens without substrate addition a bimodal breakthrough curve was observed, which could be explained by the different breakthrough behaviour of the rod-shaped and coccoidal cells of P. fluorescens. The 70:30 rod/coccoid ratio in the influent drastically changed during the transport and it was about 20:80 in the effluent and in the quartz sand packing. It was assumed that the active rod-shaped cells were subjected to shrinkage into coccoidal cells. The change from active rod-shaped cells to coccoidal cells could be explained by oxygen deficiency which occurs in column experiments under saturated conditions. Also the substrate addition led to two consecutive breakthrough peaks and to more bacteria being retained in the column. In general, the presence of substrate made the assumed stress effects more pronounced. In comparison to microspheres and inactive (killed) bacteria, the transport of metabolically-active bacteria with and without substrate addition is affected by differences in physiological state between rod-shaped and the formed stress-resistant coccoidal cells of P. fluorescens.

Relative exposure to fine particulate matter and VOCs between transport microenvironments in Dublin: Personal exposure and uptake

To compare the relative exposure to and uptake of air pollutants between modes of commuter transport, measurements of personal exposure to PM 2.5 and traffic-related VOCs were obtained over an 18-month period. In total, 468 samples were recorded comprising journeys equally divided between the four main modes of commuter transport in Dublin, Ireland: the private car, pedestrian, public bus and cyclist. Samples were recorded along two fixed routes approaching/exiting the city centre at fixed times of the day (morning and evening peak traffic flows, 08:00–09:00 and 17:00–18:00). Samples were measured using a high flow gravimetric personal sampler for PM 2.5 and a low flow vacuum operated bag sampler for VOCs. Sampling was always carried out simultaneously between two modes of transport to ensure a direct comparison regardless of meteorological and traffic conditions. Significant differences were found between the personal exposures recorded in the four modes investigated. The car commuter was found to have the highest exposure to VOCs, while the bus commuter was found to have the highest exposure to PM 2.5. The pedestrian was consistently found to have the lowest exposure. Significant differences were also found between the two fixed routes investigated. However, as there were differences in physiological states, exposure durations and exposure levels between the four modes of transport, it was deemed necessary to estimate the total uptake of pollutants by means of a numerical human respiratory tract model. The results showed the cyclist to have the highest deposition of PM 2.5 in the lungs followed by the bus, pedestrian and car. The car passenger had the highest absorption of VOCs followed by the cyclist, pedestrian and bus. Hence, the findings of the human respiratory tract model give a significantly different impression of relative uptake of pollutants to the relative exposure concentrations found initially.

Food availability and physiological state of sea urchin larvae (Strongylocentrotus purpuratus)

Food availability is highly variable in the ocean. Many species of marine invertebrates have a larval form that depends upon exogenous nutrients for growth, yet there are few biochemical and physiological indices for determining changes in the nutritional status of larvae. In this study, the effects of food availability on biochemical compositions and metabolic processes of larvae of the sea urchin, Strongylocentrotus purpuratus, were determined. Larvae were cultured under different food concentrations (fed-to-excess and unfed) and a suite of biological processes assayed, ranging from measurements at the level of the whole organism to that of specific molecules. These data were normalized to DNA content (an index of cell number) to allow comparisons of physiological rates in larvae of different sizes. Changes in the following were measured during larval growth: free amino acid pool, protein, lipid classes (cholesterol, free fatty acids, hydrocarbons, phospholipids, triacylglycerol), enzyme activities (Na+, K+-ATPase and citrate synthase), and respiration rates. In growing larvae, the two key components that showed differential cell-specific content relative to unfed larvae were glycine in the free amino acid pool and phospholipids. Additionally, several lipid classes were detectable only in fed larvae (cholesterols, free fatty acids, and hydrocarbons). While triacylglycerols were present in eggs and utilized during pre-feeding development, they were not re-accumulated at detectable levels in feeding larvae. Respiration rates, protein content, and enzyme activities were all similar on a cell-specific basis, showing that these variables did not provide useful indices of differences in physiological state between fed and unfed larvae. In contrast, measurements of the cell-specific content of glycine and certain lipid classes did provide useful indices of physiological state of larvae. Application of these indices could potentially allow for determinations of nutritional state of larvae in the ocean.

Fatty acids reduce the tensile strength of fungal hyphae during cephalosporin C production in Acremonium chrysogenum

Fragmentation rate constants, which can be used to estimate the tensile strength of fungal hyphae, were used to elucidate relationships between morphological changes and addition of fatty acids during cephalosporin C production in Acremonium chrysogenum M35. The number of arthrospores increased gradually during fermentation, and, in particular, was higher in the presence of rice oil, oleic acid or linoleic acid than in their absence. Because supplementation of rice oil or fatty acids increased cephalosporin C, we concluded that differentiation to arthrospores is related to cephalosporin C production. To estimate the relative tensile strengths of fungal hyphae, fragmentation rate constants (k (frag)) were measured. When rice oil, oleic acid, or linoleic acid were added into medium, fragmentation rate constants were higher than for the control, and hyphal tensile strengths reduced. The relative tensile strength of fungal hyphae, however was not constant presumably due to differences in physiological state.