Effects of maternal identity and incubation temperature on snapping turtle (Chelydra serpentina) metabolism

Individual variation in physiological traits may have important consequences for offspring survivorship and adult fitness. Variance in offspring phenotypes is due to interindividual differences in genotype, environment, and/or maternal effects. This study examined the contributions of incubation environment, maternal effects, and clutch identity to individual variation in metabolic rates in the common snapping turtle, Chelydra serpentina. We measured standard metabolic rate, as determined by oxygen consumption, for 246 individuals representing 24 clutches at 15 degrees and 25 degrees C, and we measured standard metabolic rates additionally for 34 individuals at 20 degrees and 30 degrees C. Standard metabolic rate for 34 snapping turtles measured at 15 degrees, 20 degrees, 25 degrees, and 30 degrees C increased with increasing temperature. Mean standard metabolic rate for 246 individuals was 0.247 microL O(2) min(-1) g(-1) at 15 degrees C and 0.919 microL O(2) min(-1) g(-1) at 25 degrees C. At 15 degrees C, mass at hatching, individual mass, and egg mass had no significant effects on metabolic rate, but at 25 degrees C, mass at hatching, individual mass, and egg mass did have significant effects on metabolic rate. Incubation temperature had no significant effect on metabolic rate at 15 degrees, but it did have a significant effect at 25 degrees C. Clutch identity had a significant effect on metabolic rate at both 15 degrees and 25 degrees C. Interindividual variation in standard metabolic rate due to incubation temperature, and especially clutch identity, could have large effects on energy budgets. Results suggest that there were both environmental and genetic effects on standard metabolic rate.     

The energetics of endotrophic development in the frog Geocrinia vitellina (Anura: Myobatrachinae).

The energetics of endotrophic development, where the nutrition required to complete metamorphosis is provided solely by yolk, has seldom been quantified. The energy cost of development to metamorphosis of the endotrophic Australian frog Geocrinia vitellina was measured using bomb calorimetry and closed-system respirometry. Dry yolk had an energy density of 26.4 J x mg(-1), and an average 2.8-mm-diameter ovum contained 144 J. Incubation at 15 degrees C produced a froglet of 5.8 mm snout-vent length, containing 88 J in 87 d, with 11% of residual yolk in the gut, which is markedly less than the 50% recorded in another endotroph, Eleutherodactylus coqui. Geocrinia vitellina lost 56 J of metabolic energy during development to metamorphosis at 15 degrees C, and the total production efficiency was 61.0%. A review of published egg energy densities found a mean for amphibians of 25.1 kJ x g(-1), significantly lower than the mean of 27.1 kJ x g(-1) for reptiles. Moreover, available amphibian data suggest that endotrophic species have high yolk energy densities and low mass-specific rates of oxygen consumption relative to exotrophic species (with feeding larvae); consequently, large ovum size may not necessarily be prerequisite for endotrophic development.     

Wiping behavior, skin resistance, and the metabolic response to dehydration in the arboreal frog Phyllomedusa hypochondrialis

Several species of arboreal frogs secrete lipids from cutaneous glands and wipe these secretions over the body surfaces to reduce evaporative water losses. Following wiping, frogs become immobile in water-conserving postures, and some have suggested they are torpid. Here we report wiping behaviors and the physiological correlates of immobile postures in the arboreal monkey frog Phyllomedusa hypochondrialis. Skin resistance to water loss was comparatively high, and rates of evaporation were as low as 4% of that from a free water surface. Standard rates of metabolism (SMR) varied from 89 microL O2 h(-1) at 18 degrees C to 316 microL O2 h(-1) at 34 degrees C and were sensitive to both temperature (T) and body mass (W; mL O2 h(-1) = 0.016W0.642 x 10(0.030T)). The mean SMR did not change significantly during four consecutive days of dehydration when animals lost 19%-34% of body mass. Therefore, it appears these frogs do not routinely depress metabolic rates following wiping. However, some individuals that lost higher percentages of body water exhibited trends of decreasing oxygen consumption, suggesting that suppression of metabolic rates might occur at greater levels of body water deficit or perhaps during a slower course of dehydration than imposed by our experiments (e.g., individuals that are secluded during periods of drought).     

Detection of testosterone propionate administration in horse hair samples

A sensitive and specific method has been developed to detect semi-quantitatively testosterone in horse hair samples. The method involved a washing step with sodium dodecylsulfate aqueous solution. The mane and tail hair samples (100mg) were dissolved in 1 mL of sodium hydroxide for 15 min at 95 degrees C in the presence of d3-boldenone used as internal standard. The next three steps involved diethyl ether extraction and a solid phase extraction on Isolute C18 (EC) cartridges eluted with methanol. The residue was derivatized by adding 100 microL of acetonitrile and 30 microL of PFPA then incubating for 15 min at 60 degrees C. After evaporation, 30 microL of hexane was added and 2.5 microL was injected into the column (a bonded phase fused silica capillary column DB5MS, 30 m x 0.25 mm i.d. x 0.25 microm film thickness) of a Trace GC chromatograph. In order to improve the sensitivity of the method, damping gas flow has been optimized. Testosterone was identified in MS(2) full scan mode on the Polaris Q instrument. The assay was capable of detecting less than 1 pg mg(-1). The recovery was close to 90%. The analysis of tail and mane samples collected from a gelding horse having received a single dose of testosterone propionate (1 mg kg(-1)) showed the presence of testosterone in the range of 1-6 pg mg(-1) in hair collected during 5 months after administration.     

Regulation of body temperature and energy requirements of hibernating alpine marmots (Marmota marmota)

Body temperature and metabolic rate were recorded continuously in two groups of marmots either exposed to seasonally decreasing ambient temperature (15 to 0 degrees C) over the entire hibernation season or to short-duration temperature changes during midwinter. Hibernation bouts were characterized by an initial 95% reduction of metabolic rate facilitating the drop in body temperature and by rhythmic fluctuations during continued hibernation. During midwinter, we observed a constant minimal metabolic rate of 13.6 ml O(2) x kg(-1) x h(-1) between 5 and 15 degrees C ambient temperature, although body temperature increased from 7.8 to 17.6 degrees C, and a proportional increase of metabolic rate below 5 degrees C ambient temperature. This apparent lack of a Q(10) effect shows that energy expenditure is actively downregulated and controlled at a minimum level despite changes in body temperature. However, thermal conductance stayed minimal (7.65 +/- 1.95 ml O(2) x kg(-1) x h(-1) x degrees C(-1)) at all temperatures, thus slowing down cooling velocity when entering hibernation. Basal metabolic rate of summer-active marmots was double that of winter-fasting marmots (370 vs. 190 ml O(2) x kg(-1) x h(-1)). In summary, we provide strong evidence that hibernation is not only a voluntary but a well-regulated strategy to counter food shortage and increased energy demands during winter.     

Effects of temperature on energy cost and timing of embryonic and larval development of the terrestrially breeding moss frog, Bryobatrachus nimbus

The Australian moss frog, Bryobatrachus nimbus, oviposits four to 16 large eggs in terrestrial nests constructed in moss or lichen in subalpine regions of southern Tasmania. Nidicolous larvae overwinter beneath snow, reaching metamorphosis without feeding after 395 d, the longest development time known for an endotrophic anuran. However, a few clutches develop more quickly and metamorphose before winter. This study examines the effect of temperature on development time and energy expenditure by measuring temperatures and developmental stages in field nests as well as rates of oxygen consumption (Vo2), developmental stage, body mass, and energy content in the laboratory at three relevant temperatures (5 degrees, 10 degrees, 15 degrees C). Eggs and larvae reared at 5 degrees C differentiated very slowly, and their development time far exceeded those in natural nests, but development times at 10 degrees and 15 degrees C averaged 277 and 149 d, respectively, and were shorter than field incubation times. Generally, respiration rates of aquatic hatchlings were low in comparison with other species but increased with larval age and jumped about 25% higher near metamorphosis when larvae were able to air breathe. The mean energy density was 26.0 J mg(-1) for the dry ova and 20.6 J mg(-1) for a dry gut-free froglet, and total production efficiency was 61.5%. We developed a model based on the relationships between incubation temperature and V&d2;o2 to estimate the respiratory cost of development to metamorphosis, the first such study for an amphibian. The cost was 177 J at 15 degrees C, 199 J at 10 degrees C, and at least 249 J at 5 degrees C, and we predicted that continual development at 5 degrees C would lead to premature yolk depletion because it equalled the 249 J contained in fresh ova. Continuously logged field-nest temperatures and interpolation of laboratory data provided estimates of development rates, Vo2, and respiratory energy costs in field nests. Development to metamorphosis required between 185 and 234 J when larvae overwintered, but completion of metamorphosis before winter saved 123 J. However, the advantage of emergence in warmer months, when conditions are suitable for feeding and growth, may offset the greater energy cost of overwintering.     

Energy metabolism during larval development of green and white abalone,Haliotis fulgens and H. sorenseni

An understanding of the biochemical and physiological energetics of lecithotrophic development is useful for interpreting patterns of larval development, dispersal potential, and life-history evolution. This study investigated the metabolic rates and use of biochemical reserves in two species of abalone, Haliotis fulgens (the green abalone) and H. sorenseni (the white abalone). Larvae of H. fulgens utilized triacylglycerol as a primary source of endogenous energy reserves for development ( approximately 50% depletion from egg to metamorphic competence). Amounts of phospholipid remained constant, and protein dropped by about 30%. After embryogenesis, larvae of H. fulgens had oxygen consumption rates of 81.7 +/- 5.9 (SE) pmol larva(-1) h(-1) at 15 degrees C through subsequent development. The loss of biochemical reserves fully met the needs of metabolism, as measured by oxygen consumption. Larvae of H. sorenseni were examined during later larval development and were metabolically and biochemically similar to H. fulgens larvae at a comparable stage. Metabolic rates of both species were very similar to previous data for a congener, H. rufescens, suggesting that larval metabolism and energy utilization may be conserved among closely related species that also share similar developmental morphology and feeding modes.     

Evidence of UCP1-independent regulation of norepinephrine-induced thermogenesis in brown fat

To study the thermal response of interscapular brown fat (IBF) to norepinephrine (NE), urethan-anesthetized rats (1.2 g/kg ip) maintained at 28-30 degrees C received a constant venous infusion of NE (0-2 x 10(4) pmol/min) over a period of 60 min. IBF temperatures (T(IBF)) were recorded with a small thermistor fixed under the IBF pad. Data were plotted against time and expressed as maximal variation (Deltat degrees C). Saline-injected rats showed a decrease in T(IBF) of approximately 0.6 degrees C. NE infusion increased T(IBF) by a maximum of approximately 3.0 degrees C at a dose of 10(4) pmol x min(-1) x 100 g body wt(-1). Surgically thyroidectomized (Tx) rats kept on 0.05% methimazole showed a flat response to NE. Treatment with thyroxine (T(4), 0.8 microg x 100 g(-1) x day(-1)) for 2-15 days normalized mitochondrial UCP1 (Western blotting) and IBF thermal response to NE, whereas iopanoic acid (5 mg x 100 g body wt(-1) x day(-1)) blocked the effects of T(4). Treatment with 3,5, 3'-triiodothyronine (T(3), 0.6 microg x 100 g body wt(-1) x day(-1)) for up to 15 days did not normalize UCP1 levels. However, these animals showed a normal IBF thermal response to NE. Cold exposure for 5 days or feeding a cafeteria diet for 20 days increased UCP1 levels by approximately 3.5-fold. Nevertheless, the IBF thermal response was only greater than that of controls when maximal doses of NE (2 x 10(4) pmol/min and higher) were used. Conclusions: 1) hypothyroidism is associated with a blunted IBF thermal response to NE; 2) two- to fourfold changes in mitochondrial UCP1 concentration are not necessarily translated into heat production during NE infusion.     

Measurement of amoxicillin in plasma and gastric samples using high-performance liquid chromatography with fluorimetric detection

A rapid, selective and sensitive HPLC assay has been developed for the routine analysis of amoxicillin in rat plasma, gastric juice aspirate and gastric tissue which is applicable to low concentrations of amoxicillin (<1 microg mL(-1)) or small sample volumes. Amoxicillin was converted, via an internal rearrangement, to form a fluorescent product which was subsequently recovered using liquid-liquid extraction. A Kromasil ODS 3 microm (150 x 3.2 mm I.D.) column was maintained at 40 degrees C and used with a mobile phase consisting of methanol-water (55:45, v/v). Fluorimetric detection was at an lambda(ex) of 365 nm and an lambda(em) of 445 nm. The limits of quantitation for amoxicillin were 0.1 microg mL(-1) for gastric juice aspirate (500 microL), 0.5 microg mL(-1) for plasma (50 microL) and 0.075 microg g(-1) for gastric tissue (250 mg). The method was linear up to at least 15 microg mL(-1) in gastric juice aspirate, up to 200 microg mL(-1) in plasma and up to 100 microg g(-1) in gastric tissue, with inter- and intra-day RSDs being less than 19%. The assay has been applied to the measurement of amoxicillin in rat plasma, gastric juice aspirate and gastric tissue for pharmacokinetic studies in individual rats.     

Effects of centrifugation, glycerol level, cooling to 5 degrees C, freezing rate and thawing rate on the post-thaw motility of equine sperm

Five experiments evaluated the effects of processing, freezing and thawing techniques on post-thaw motility of equine sperm. Post-thaw motility was similar for sperm frozen using two cooling rates. Inclusion of 4% glycerol extender was superior to 2 or 6%. Thawing in 75 degrees C water for 7 sec was superior to thawing in 37 degrees C water for 30 sec. The best procedure for concentrating sperm, based on sperm motility, was diluting semen to 50 x 10(6) sperm/ml with a citrate-based centrifugation medium at 20 degrees C and centrifuging at 400 x g for 15 min. There was no difference in sperm motility between semen cooled slowly in extender with or without glycerol to 5 degrees C prior to freezing to -120 degrees C and semen cooled continuously from 20 degrees C to -120 degrees C. From these experiments, a new procedure for processing, freezing and thawing semen evolved. The new procedure involved dilution of semen to 50 x 10(6) sperm/ml in centrifugation medium and centrifugation at 400 x g for 15 min, resuspension of sperm in lactose-EDTA-egg yolk extender containing 4% glycerol, packaging in 0.5-ml polyvinyl chloride straws, freezing at 10 degrees C/min from 20 degrees C to -15 degrees C and 25 degrees C/min from -15 degrees C to -120 degrees C, storage at -196 degrees C, and thawing at 75 degrees C for 7 sec. Post-thaw motility of sperm averaged 34% for the new method as compared to 22% for the old method (P<0.01).     

Controlled bioassay systems for determination of lethal infective doses of tissue homogenates containing Taura syndrome or white spot syndrome virus

In vivo bioassay is the predominant method for evaluating the infectivity of materials potentially harboring viable shrimp pathogens and determining the relative susceptibility of shrimp species to viral infections. A controlled bioassay system for white spot syndrome virus (WSSV) and Taura syndrome virus (TSV) was developed utilizing 260 ml tissue culture flasks modified with an air exchange vent. Individual shrimp (1.00 +/- 0.25 g) were placed in separate flasks containing artificial seawater (100 to 150 ml) and held in an incubator at 27 degrees C. After a 48 h acclimation period, shrimp were either injected intramuscularly with viral inoculum or exposed to virus-laden water. Water was exchanged and shrimp were fed a commercial food pellet daily except 24 h post-infection (p.i.). Bioassays were performed with serial dilutions of stock viral preparations and shrimp mortality was recorded for 7 d p.i. Mortality rates of test animals permitted the estimation of the lethal infective doses, LD50 and LD90. The LD50 of the TSV injection preparation was estimated at viral dilutions of 1:7.692 x 10(7) (Trial 1) and 1:6.667 x 10(7) (Trial 2). The LD50s of 2 different WSSV injection preparations were estimated at 1:4.444 x 10(6) and 1:4.505 x 10(6). The LD50 for the TSV waterborne challenge was 1:9916 (Trial 1) and 1:15 710 (Trial 2) at 20 degrees C and 1:1272 at 27 degrees C. A second waterborne TSV inoculum challenge at 27 degrees C produced an LD50 of 1:2857. WSSV doses used in the waterborne challenge only reached 39% mortality, which did not allow for the estimation of effective lethal doses. Bioassay by injection proved to be a more reliable method of estimating viral infectivity compared to waterborne method. The dose-response curves developed can serve as a basis for controlled comparisons of relative levels of viral infectivity of specific tissue preparations and for controlled comparisons of relative susceptibility of shrimp species or stocks to viral pathogens.     

Energy balance and cold adaptation in the octopus Pareledone charcoti

A complete energy balance equation is calculated for the Antarctic octopus Pareledone charcoti at 0 degrees C. Energy used in respiration, growth, and excretion of nitrogenous and faecal waste, was recorded along with the total consumption of energy through food, for three specimens of P. charcoti (live weights: 73, 51 and 29 g). Growth rates were very slow for cephalopods, with a mean daily increase in body weight of only 0.11%. Assimilation efficiencies were high, between 95.4 and 97.0%, which is consistent with previous work on octopods. The respiration rate in P. charcoti was low, with a mean of 2.45 mg O(2) h(-1) for a standard animal of 150 g wet mass at 0 degrees C. In the North Sea octopus Eledone cirrhosa, respiration rates of 9.79 mg O(2) h(-1) at 11.5 degrees C and 4.47 mg O(2) h(-1) at 4.5 degrees C for a standard animal of 150 g wet mass were recorded. Respiration rates between P. charcoti and E. cirrhosa were compared using a combined Q(10) value between P. charcoti at 0 degrees C and E. cirrhosa at 4.5 degrees C. This suggests that P. charcoti are respiring at a level predicted by E. cirrhosa rates at 4.5 and 11.5 degrees C extrapolated to 0 degrees C along the curve Q(10)=3, with no evidence of metabolic compensation for low temperature.     

Blood and extracellular fluid volume in whole body and tissues of the Pacific hagfish, Eptatretus stouti

Whole-body and 20 individual-tissue (51)Cr-RBC (red cell space; RCS) and (99)Tc-diethylenetriaminepentaacetic acid (extracellular space; ECS) spaces were measured in seven unanesthetized Pacific hagfish (Eptatretus stouti). Volume indicators were administered via a dorsal aortic cannula implanted the previous day. Blood samples were collected at 6, 12, 18, and 24 h after injection. Tissues were removed at 24 h and radioactivity was measured; tissue water content (percent of wet weight) was determined by desiccation at 95 degrees C for 48 h. Mixing rates of both indicators were identical and were essentially complete by 12 h, indicating that blood convection is the rate-limiting process. At 24 h, the whole-body RCS was 19.3+/-2.1 mL kg(-1) body weight, and the ECS was 338.5+/-15.2 mL kg(-1) body weight. Blood volume estimated from the 24-h RCS and the mean central hematocrit (14%) was 137.9 mL kg(-1) body weight. Liver RCS (118.6+/-30.5 microL g(-1) tissue weight) was twice that of any other tissue and was also the most variable, ranging from 59 to 263 microL g(-1), whereas liver ECS (406.0+/-34.3 microL g(-1)) was in the range of other tissues, and water content (66.9%+/-3.5%) was low. Gill RCS (55.9+/-5.7 microL g(-1)), ECS (415.3+/-37.7 microL g(-1)), and percent water (83.1%+/-0.8%) were higher than most other tissues. RCS, ECS, and percent water were consistently lowest in ovum (1.1+/-0.02 microL g(-1), 111.1+/-4.3 microL g(-1), 51.3%+/-3.5%, respectively). Tongue, notocord, and myotome had generally lower RCS (2.1+/-0.4, 2.2+/-0.5, 7.1+/-0.1 microL g(-1), respectively) and ECS (121.2+/-7.0, 246.3+/-17.4, 185.3+/-16.7 microL g(-1), respectively), although their water content was in the midrange (74.7+/-0.5, 81.2+/-1.6, 74.4%+/-0.6%, respectively). Skin had a low RCS (6.8+/-1.1) and midrange ECS (387.5+/-28.0) but very low water content (61.2%+/-2.1%). These findings confirm that hagfish blood volume is at least twice as large as other fish, whereas our estimate of extracellular fluid volume is larger than previously reported and more in line with the predicted interstitial volume. RCS, ECS, and water content vary, often independently, between tissues, which may perhaps be indicative of specific tissue needs or functions. A distinct spleen is lacking in hagfish, and the liver appears to serve this function by sequestering red cells. To our knowledge, this is the first report of tissue ECS in Myxiniformes.     

Performance enhancement in rally car drivers via heat acclimation and race simulation

To investigate the combined use of an interactive racecar simulator and heat acclimation on psychomotor (driving) performance, eight rally drivers underwent 4 days of repeated heat (50 degrees C) exposure (1 h x day(-1)) during which they performed a simulated rally drive (3x12-min stages each separated by a 2-min break), after first cycling for 15 min at 125 W to induce some degree of fatigue and heat storage prior to beginning the rally. During the rally stages, a generic set of pace notes were read to the subject by a co-driver. In each simulation, sweat loss, heart rate, core (rectal) and skin temperatures were recorded and driving and psychomotor performance were assessed by recording stage times and time to complete a psychomotor test. Levels of physiological and perceived thermal strain were also recorded. Significant decreases in rally stage times (88 s; P<0.005), psychomotor test time (18 s; P<0.01), final core (0.25 degrees C; P<0.001) and skin (0.44 degrees C; P<0.005) temperatures, heart rate (16 beats x min(-1); P<0.05) and physiological (15 W x m(-2); P<0.005) and perceived thermal (3.7 units; P<0.01) strain were evident by the end of the final simulation, and a significant (P<0.05) increase in sweat sensitivity (+0.33 g x h(-1) x degrees C(-1)) was also recorded. These results suggest that both heat acclimation and race simulation can improve the psychomotor performance of rally drivers, although the relative contribution of each factor was not determined here. However, in a practical setting, these factors would not be used in isolation. After performing the acclimation and simulation protocol prior to an actual rally, drivers subjectively reported improvements in tolerating a high thermal load and in their ability to control the rally vehicle.     

Body temperature, heart rate and oxygen consumption of normothermic and heterothermic western jumping mice (Zapus princeps)

1. Heart rates and oxygen consumption were measured for normothermic, hibernating, and arousing Zapus princeps. 2. Rectal and oral body temperature were monitored and differential rates of rewarming of the body were recorded. 3. Lengths of periodic arousals differ in two stages of hibernation; days 50-80 arousal durations were 12 hr, 43 min while days 140-210 were 10 hr, 28 min. 4. Total energy budget of hibernation was calculated for a 295 day hibernation cycle based on the utilization of 18,020 cc of oxygen for that period. The calculated utilization of fat would be 8.97 g while the observed use was 9.5-11.1 g.     

Development of foamed emulsion bioreactor for air pollution control

A new type of bioreactor for air pollution control has been developed. The new process relies on an organic-phase emulsion and actively growing pollutant-degrading microorganisms, made into a foam with the air being treated. This new reactor is referred to as a foamed emulsion bioreactor (FEBR). As there is no packing in the reactor, the FEBR is not subject to clogging. Mathematical modeling of the process and proof of concept using a laboratory prototype revealed that the foamed emulsion bioreactor greatly surpasses the performance of existing gas-phase bioreactors. Experimental results showed a toluene elimination capacity as high as 285 g(toluene) m(-3) (reactor) h(-1) with a removal efficiency of 95% at a gas residence time of 15 s and a toluene inlet concentration of 1-1.3 g x m(-3). Oxygen limited the reactor performance at toluene concentration above about 0.7-1.0 g x m(-3); consequently, performance was significantly improved when pure oxygen was added to the contaminated air. The elimination capacity increased from 204 to 408 g x m(-3) h(-1) with >77% toluene removal at toluene inlet concentrations of 2-2.2 g x m(-3). Overall, the results show that the performance of the FEBR far exceeds that of currently used bioreactors for air pollution control.     

Nonfaecal and faecal losses of Pomadasys commersonni (Teleostei: Pomadasyidae) feeding on the surf clam, Donax serra

1. The nonfaecal and the faecal production of Pomadasys commersonni, a marine teleost, were investigated at 15, 20 and 25 degrees C. 2. Nonfaecal nitrogen excreted by starved and fed P. commersonni consisted mainly of ammonia-N. 3. The mass component b of the equation, AE = aMb (AE, ammonia-N in Mg-N/hr; M, fish mass in g) ranged from 0.68-0.72 and 0.71-0.75 for starved and fed fish, respectively, and was temperature-independent. 4. The mean percentage of the food energy lost as nonfaecal energy (exogenous plus endogenous) was 4.38 +/- 2.68%. 5. The faeces had a low energy content and ranged from 2.09 to 4.25 kJ/g. 6. Assimilation efficiencies showed some variation and ranged from 7.34 to 99.34% for dry matter and from 96.02 to 99.89% for energy. 7. The mean combined energy loss was 11.77% of the ingested energy.     

Hydroxyeicosatetraenoic acids are increased in bronchoalveolar lavage fluid of endotoxemic pigs

We hypothesized that lipoxygenase metabolites of arachidonic acid might be produced during endotoxin-induced acute respiratory failure (ARF) observed in young pigs. We used radioimmunoassay (RIA) to determine the presence of 5-hydroxyeicosatetraenoic acid (5-HETE), 12-HETE, and 15-HETE in bronchoalveolar lavage fluid (BALF) of saline (n=12)- and endotoxin (n=18)- treated pigs. Endotoxin, infused at 5 μg/kg for 1 hr followed by 2 μg/kg/hr for an average of 3 hrs, caused pulmonary hypertension, a biphasic increase in pulmonary vascular resistance, hypoxemia, bronchoconstriction, leukopenia, and thrombocytopenia. Relative to saline controls, the levels of immunoreactive (i)-5-HETE (816 ± 209 pg/ml), i-12-HETE (1589 ± 517 pg/ml), and i-15-HETE (448 ± 78 pg/ml) were significantly ) increased in BALF recovered from endotoxemic pigs at postmortem. Relative to control BALF i-HETE concentrations, the endotoxin values were 3.5x, 5.1x, and 2.8x higher for i-5-HETE, i-12-HETE, and i-15-HETE, respectively. We conclude that during porcine endotoxemia, the 5-, 12-, and 15-lipoxygenase pathways are activated and that HETES might be involved in the pathophysiology of endotoxin-induced ARF.     

The isolation and use of iron-oxidizing,moderately thermophilic acidophiles from the Collie coal mine for the generation of ferric iron leaching solution

Moderately thermophilic, iron-oxidizing acidophiles were enriched from coal collected from an open-cut mine in Collie, Western Australia. Iron-oxidizers were enriched in fluidized-bed reactors (FBR) at 60 degrees C and 70 degrees C; and iron-oxidation rates were determined. Ferrous iron oxidation by the microbiota in the original coal material was inhibited above 63;C. In addition to four iron-oxidizers, closely related to Sulfobacillus spp that had been earlier isolated from the 60 degrees C FBR, one heterotroph closely related to Alicyclobacillus spp was isolated. The Alicyclobacillus sp. isolated from the Collie coal mine tolerated a lower pH than known Alicyclobacillus spp and therefore may represent a new species. The optimum temperature for growth of the iron-oxidizing strains was approximately 50 degrees C and their maximum temperatures were approximately 60 degrees C. The FBR was adjusted to operate at 50 degrees C and was inoculated with all of the isolated iron-oxidizing strains. At 60 degrees C, an iron-oxidation rate of 0.5 g Fe(2+) l(-1) x h(-1) was obtained. At 50 degrees C, the iron-oxidation rate was only 0.3 g Fe(2+) l(-1) x h(-1). These rates compare favourably with the iron-oxidation rate of Acidianus brierleyi in shake-flasks, but are considerably lower than mesophilic iron-oxidation rates.