Influences of carotenoid supplementation on the integrated antioxidant system of a free living endangered passerine, the hihi (Notiomystis cincta)

The integrated antioxidant system is recognised as an essential component of an organisms self maintenance. Our knowledge of this system, however, is largely restricted to species of economic importance. The health and productivity benefits these dietary based compounds provide make them increasingly relevant for study in wildlife ecology. The aim of this research was to identify numerous components of this integrated system in a free living and endangered passerine bird, the hihi. In addition experimental supplementation with carotenoids was used to investigate the modulatory interactions with other members of the antioxidant system. Our results identified lutein and zeaxanthin as the carotenoids utilised by hihi (82% and 17% of total carotenoids respectively in control samples of egg yolk, 84% and 16% of total carotenoids respectively in control samples of nestling plasma), and that vitamin E was represented by both alpha- and gamma-tocopherol. Retinol was also present, as was selenium in surprisingly high concentrations (599.64, 91.76, 377.72 ng/g fresh weight Se in control samples of yolk, albumin and plasma, respectively). Supplementation of lutein and zeaxanthin not only increased their presence in egg yolk (F(1,10)=14.285, P=0.005 and F(1,10)=9.606, P=0.015, respectively) and nestling plasma (F(1,19)=35.126, P<0.001 and F(1,19)=28.597, P<0001, respectively) but also led to increased selenium concentration in egg yolk (F(1,10)=7.213, P=0.028), increased retinol concentration in nestling plasma (F(1,19)=4.272, P=0.054) and decreased alpha-tocopherol concentration in nestling plasma (F(1,19)=5.122, P=0.037). These results provide detail of the antioxidant system in novel taxa and importantly highlight interaction between these various compounds. Given their increased application in productivity and health in agriculture and human medicine we highlight the potential application of this knowledge in wildlife ecology and conservation.     

Molecular characterization of microsporidia indicates that wild mammals Harbor host-adapted Enterocytozoon spp. as well as human-pathogenic Enterocytozoon bieneusi

Over 13 months, 465 beavers, foxes, muskrats, otters, and raccoons were trapped in four counties in eastern Maryland and examined by molecular methods for microsporidia. A two-step nested PCR protocol was developed to amplify a 392-bp fragment of the internal transcribed spacer region of the rRNA gene of Enterocytozoon spp., with the use of primers complementary to the conserved regions of published nucleotide sequences. Fifty-nine PCR-positive samples were sequenced. Multiple alignments of these sequences identified 17 genotypes of Enterocytozoon spp. (WL1 to WL17); of these, 15 have not been reported before. Most of the genotypes were found in multiple species of wildlife and belonged to a major group consisting of all the previously described Enterocytozoon bieneusi genotypes from human and domestic animals. Some of the isolates from muskrats and raccoons formed two distinct groups. Results of this study indicate that fur-bearing mammals, especially those closely associated with surface water, can be a potential source of human-pathogenic E. bieneusi. However, there are also host-adapted Enterocytozoon genotypes in wildlife, which may represent species different from E. bieneusi and have no apparent public health significance. This is the first report of E. bieneusi in wildlife.     

Clinico-Pathologic Findings in Young Pigs Fed Different Levels of Selenium,Vitamin E and Antioxidant

A randomized, blocked 23 factorial experiment was conducted with 48 young pigs. The treatment factors were: 2 levels of selenium (55 and 115 µg/kg), 2 levels of vitamin E (3 and 53 mg/kg) and 2 levels of the antioxidant feed additive Ethoxyquin (0 and 150 mg/kg). All pigs were kept in single pens and fed ad libitum throughout the experimental period of 9 weeks, i.e. from 3 to 12 weeks of age. Plasma, heart, liver and muscle Se levels as well as whole blood glutathione peroxidase activity (EC 1.11.1.9 GSH-Px) were significantly higher in pigs given a dietary supplement of Se than in pigs given no supplement of Se (P ≤ 0.001). The Se-supplemented pigs showed a tendency to lower mean serum transaminase activity (ASAT and ALAT) than unsupplemented pigs, but the influence was significant (P ≤ 0.05) only for the ALAT activity. Blood vit. E levels were higher for pigs receiving a supplement of vit. E than for unsupplemented pigs (P ≤ 0.001), and so was the resistance of red blood cells against lipid peroxidation (ELP), as expressed by lower ELP values. There were no effects of Ethoxyquin supplementation on the biochemical variables included in the study. The histological examination of heart muscle showed that the score for changes was negatively influenced by both Se and vit. E supplement (P ≤ 0.001) and to some extent also by Ethoxyquin supplement (P ≤ 0.05). The histological picture of m. long dorsi was influenced only by the vit. E supplement (P ≤ 0.01). No histological changes were found in the liver in this study. There were inverse relationships between whole blood GSH-Px defluorescence time and blood Se, and between ELP and whole blood vit. E (P ≤ 0.001).     

Molecular Characterization of Microsporidia Indicates that Wild Mammals Harbor Host-Adapted Enterocytozoon spp. as well as Human-Pathogenic Enterocytozoon bieneusi

Over 13 months, 465 beavers, foxes, muskrats, otters, and raccoons were trapped in four counties in eastern Maryland and examined by molecular methods for microsporidia. A two-step nested PCR protocol was developed to amplify a 392-bp fragment of the internal transcribed spacer region of the rRNA gene of Enterocytozoon spp., with the use of primers complementary to the conserved regions of published nucleotide sequences. Fifty-nine PCR-positive samples were sequenced. Multiple alignments of these sequences identified 17 genotypes of Enterocytozoon spp. (WL1 to WL17); of these, 15 have not been reported before. Most of the genotypes were found in multiple species of wildlife and belonged to a major group consisting of all the previously described Enterocytozoon bieneusi genotypes from human and domestic animals. Some of the isolates from muskrats and raccoons formed two distinct groups. Results of this study indicate that fur-bearing mammals, especially those closely associated with surface water, can be a potential source of human-pathogenic E. bieneusi. However, there are also host-adapted Enterocytozoon genotypes in wildlife, which may represent species different from E. bieneusi and have no apparent public health significance. This is the first report of E. bieneusi in wildlife.     

Heat increment of feeding and its thermoregulatory benefit in the muskrat (Ondatra zibethicus)

The calorigenic effect of feeding and its potential benefit in defraying thermoregulatory costs and attenuating immersion hypothermia of adult muskrats were investigated. A single session of feeding on aquatic vegetation was sufficient to raise the metabolic rate of muskrats for a period of at least 5 h. The peak postprandial rate of oxygen consumption averaged 1.42 times the level established for fasted animals, and the heat increment of feeding accounted for about 40% of the metabolizable energy intake of muskrats. There was no evidence of a postprandial rise in oxygen consumption of muskrats that entered water at 18–19°C after feeding. In aquatic trials, average and minimum steady-state oxygen consumption rates of fed muskrats were similar to, or even lower than values recorded from fasted animals, implying substitution of heat increment of feeding for thermoregulatory heat production. Our data did not support the hypothesis that heat increment of feeding retards body cooling in water. Net body temperature decline in water was actually higher in fed animals than in fasted controls. However, since previously fed muskrats also entered water at an elevated body temperature, the final body temperature (at 30 min immersion) was similar in all groups. These findings suggest that metabolic heat generated incidental to preimmersion feeding could provide a thermoregulatory benefit to muskrats by reducing the need for active thermogenesis in water.     

The comparison of immobility time in experimental rat swimming models

Rat swimming models have been used in studies about stress and depression. However, there is no consensus about interpreting immobility (helplessness or adaptation) in the literature. In the present study, immobility time, glucose and glycogen mobilization, corticosterone and the effect of desipramine and diazepam were investigated in two different models: swimming stress and the forced swimming test. Immobility time was lower in swimming stress than in the forced swimming test. Both swimming models increased corticosterone levels in comparison with control animal levels. Moreover, swimming stress induced higher corticosterone levels than the forced swimming test did [F(2,14)=59.52; p<0.001]. Liver glycogen content values differed from one another (swimming stress相似文献   

Effects of aging on hematology and serum clinical chemistry in chimpanzees (Pan troglodytes)

A number of age-related changes in physiological functions have been identified in macaques and humans. However, few studies have examined physiological aging in chimpanzees, despite the increasing age of the chimpanzee population. We documented age-related changes in seven hematology and 17 clinical chemistry parameters in 49 adult chimpanzees (17 males, 32 females) as a comparative viewpoint with human and macaque aging. Longitudinal data were analyzed using weighted linear and quadratic mixed effects regression models. Male chimpanzees exhibited a significant age-related increase in anemia risk, based on significant decreases in hemoglobin (F(1,49)=12.45, P=0.0009) and hematocrit (F(1,49)=15.42, P=0.0003). Both sexes exhibited significant age-related decreases in both kidney and liver function. Decreases in kidney function were noted by significant increases in blood urea nitrogen (F(1,45)=3.92, P=0.036) and creatinine (F(1,50)=5.63, P=0.022) as well as changes in electrolyte (i.e., sodium, potassium, phosphorous, chloride) balance. Declining liver function was based on significant increases in globulin (F(1,46)=32.34, P<0.0001) and decreases in albumin (F(1,48)=23.42, P<0.0001). These changes were most evident beginning at 25-30 years of age in males and 30-35 years of age in females. We recommend amending chimpanzee age classes to categorize males over 25 years and females over 30 years as aged.     

Photo- and antioxidative protection,and a role for salicylic acid during drought and recovery in field-grown<Emphasis Type="Italic"> Phillyrea angustifolia</Emphasis> plants

Mechanisms of photo- and antioxidative protection, the extent of oxidative stress, and salicylic acid accumulation in leaves of Phillyrea angustifolia L. (Oleaceae) plants exposed to drought and recovery in Mediterranean field conditions were studied. The amounts of alpha-tocopherol increased up to 4-fold and those of zeaxanthin increased up to 3-fold at relative leaf water contents (RWCs) of ca. 60%, which caused up to 70% increases in the de-epoxidation state of the xanthophyll cycle (DPS). While alpha-tocopherol increased further in severe drought, zeaxanthin levels and DPS remained constant, beta-carotene decreased and malondialdehyde (MDA) levels increased at RWCs below 50%. Though this was associated with significant decreases in the maximum efficiency of photosystem II photochemistry (F(v)/ F(m)), the same leaves that suffered from drought recovered after rainfalls, and similar MDA levels and F(v)/ F(m) ratios to those observed before drought were attained. During recovery (i) the F(v)/ F(m) ratio and beta-carotene levels increased slowly, (ii) alpha-tocopherol levels decreased sharply, to increase again, and (iii) MDA levels in leaves increased to values 35% higher than those observed at maximum drought, and decreased later. Salicylic acid (SA) levels showed a strong negative correlation (r(2)=0.857) with the RWC, and increased progressively up to 5-fold, during drought. During recovery, SA levels decreased, but remained slightly higher than those observed before drought. SA levels were positively correlated with those of alpha-tocopherol during drought (r(2)=0.718), but not during recovery (r(2)=0.221). We conclude that (i) P. angustifolia plants activate several mechanisms of photo- and antioxidative protection to withstand drought stress during a Mediterranean summer, (ii) endogenous SA levels increase in leaves of drought-stressed plants, thus suggesting a role for SA in plant responses to drought, and (iii) plants suffer oxidative stress during recovery, and this stress is more severe as the previous drought is more intense.     

Body oxygen stores, aerobic dive limits, and the diving abilities of juvenile and adult muskrats (Ondatra zibethicus)

Intraspecific variability in body oxygen reserves, muscle buffering capacity, diving metabolic rate, and diving behavior were examined in recently captured juvenile and adult muskrats. Allometric scaling exponents for lung (b=1.04), blood (b=0.91), and total body oxygen storage capacity (b=1.09) did not differ from unity. The concentration of skeletal muscle myoglobin scaled positively with mass in 254-600-g juveniles (b=1.63) but was mass-independent in larger individuals. Scaling exponents for diving metabolic rate and calculated aerobic dive limit (ADL) were 0.74 and 0.37, respectively. Contrary to allometric predictions, we found no evidence that the diving abilities of muskrats increased with age or body size. Juveniles aged 1-2 mo exhibited similar dive times but dove more frequently than summer-caught adults. Average and cumulative dive times and dive&rcolon;surface ratios were highest for fall- and winter-caught muskrats. Total body oxygen reserves were greatest in winter, mainly due to an increase in blood oxygen storage capacity. The buffering capacity of the hind limb swimming muscles also was highest in winter-caught animals. Several behavioral indicators of dive performance, including average and maximum duration of voluntary dives, varied positively with blood hemoglobin and muscle myoglobin concentration of muskrats. However, none of the behavioral measures were strongly correlated with the total body oxygen reserves or ADLs derived for these same individuals.     

Hematologic and blood chemical characteristics of feral horses from three management areas

Blood was collected from 486 feral horses of mixed sex and age classes captured from three wild horse management areas in Nevada and Oregon from December 1985 to February 1986. Males were significantly outnumbered by females in the Flanigan area, but both sexes were represented in approximately equal numbers in the Wassuk and Beaty's Butte areas. Hematology and chemistry values averaged 16.4 +/- 0.11, 46.3 +/- 0.28, 9.9 +/- 0.07, 6.9 +/- 0.10, 47.1 +/- 0.24, 16.6 +/- 0.09, 35.2 +/- 0.09, 10.4 +/- 0.14 and 23.4 +/- 0.25 for hemoglobin (HGB), hematocrit (HCT), red blood cells (RBC), white blood cells (WBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), cortisol (F) and serum urea nitrogen (SUN), respectively. Statistically significant differences in HGB, HCT, RBC, WBC, MCV and MCH levels occurred with respect to age (P less than or equal to 0.001). Serum F levels were lower in immature animals than in either subadult or adults in all areas. Flanigan horses appeared in the poorest condition and had the lowest HGB, HCT and RBC counts while the values for Wassuk horses were significantly higher (P less than or equal to 0.001). Serum F levels were lowest in the Flanigan horses. A significantly lower (P less than or equal to 0.001) proportion of adult mares had progesterone levels consistent with pregnancy in the Flanigan horses versus those from the other two areas. These data are consistent with a subjective evaluation of the condition of the horses.     

Tyrosine radical formation in the reaction of wild type and mutant cytochrome P450cam with peroxy acids: a multifrequency EPR study of intermediates on the millisecond time scale

We report a multifrequency (9.6-, 94-, 190-, and 285-GHz) EPR study of a freeze-quenched intermediate obtained from reaction of substrate-free cytochrome P450cam (CYP101) and its Y96F and Y96F/Y75F mutants with peroxy acids. It is generally assumed that in such a shunt reaction an intermediate [Fe(IV)=O, porphyrin-pi-cation radical] is formed, which should be identical to the species in the natural reaction cycle. However, for the wild type as well as for the mutant proteins, a porphyrin-pi-cation radical is not detectable within 8 ms. Instead, EPR signals corresponding to tyrosine radicals are obtained for the wild type and the Y96F mutant. Replacement of both Tyr-96 and Tyr-75 by phenylalanine leads to the disappearance of the tyrosine EPR signals. EPR studies at 285 GHz on freeze-quenched wild type and Y96F samples reveal g tensor components for the radical (stretched g(x) values from 2.0078 to 2.0064, g(y) = 2.0043, and g(z) = 2.0022), which are fingerprints for tyrosine radicals in a heterogeneous polar environment. The measurements at 94 GHz using a fundamental mode microwave resonator setup confirm the 285-GHz study. From the simulation of the hyperfine structure in the 94-GHz EPR spectra the signals have been assigned to Tyr-96 in the wild type and to Tyr-75 in the Y96F mutant. We suggest that a transiently formed Fe(IV)=O porphyrin-pi-cation radical intermediate in P450cam is reduced by intramolecular electron transfer from these tyrosines within 8 ms.     

Pyrazolinone-piperidine dipeptide growth hormone secretagogues (GHSs). Discovery of capromorelin

Novel pyrazolinone-piperidine dipeptide derivatives were synthesized and evaluated as growth hormone secretagogues (GHSs). Two analogues, capromorelin (5, CP-424391-18, hGHS-R1a K(i)=7 nM, rat pituicyte EC(50)=3 nM) and the des-methyl analogue 5c (hGHS-R1a K(i)=17 nM, rat pituicyte EC(50)=3 nM), increased plasma GH levels in an anesthesized rat model, with ED(50) values less than 0.05 mg/kg iv. Capromorelin showed enhanced intestinal absorption in rodent models and exhibited superior pharmacokinetic properties, including high bioavailabilities in two animal species [F(rat)=65%, F(dog)=44%]. This short-duration GHS was orally active in canine models and was selected as a development candidate for the treatment of musculoskeletal frailty in elderly adults.     

Mating system variation in the hermaphroditic brooding coral, Seriatopora hystrix

Self-compatible, hermaphroditic marine invertebrates have the potential to self-fertilize in the absence of mates or under sperm-limited conditions, and outcross when sperm is available from a variety of males. Hence, many hermaphroditic marine invertebrates may have evolved mixed-mating systems that involve facultative self-fertilization. Such mixed-mating strategies are well documented for plants but have rarely been investigated in animals. Here, I use allozyme markers to make estimates of selfing from population surveys of reef slope and reef flat sites, and contrast this with direct estimates of selfing from progeny-array analysis, for the brooding coral Seriatopora hystrix. Consistent heterozygote deficits previously reported for S. hystrix suggests that inbreeding (including the extreme of selfing) may be common in this species. I detected significant levels of inbreeding within populations (F(IS)=0.48) and small but significant differentiation among all sites (F(ST)=0.04). I detected no significant differentiation among habitats (F(HT)=0.009) though among site differentiation did occur within the reef slope habitat (F(SH)=0.06), but not within the reef flat habitat (F(SH)=0.015). My direct estimates of outcrossing for six colonies and their progeny from a single reef flat site revealed an intermediate value (t(m) (+/-s.d.)=0.53+/-0.20). Inbreeding coefficients calculated from progeny arrays (F(e)=0.31) were similar to indirect estimates based on adult genotype frequencies for that site (F(IS)=0.38). This study confirms that the mating system of this brooding coral is potentially variable, with both outcrossing and selfing.     

Tyzzer's disease in muskrats: re-examination of specimens of hemorrhagic disease collected by Paul Errington

Organisms typical of those seen in Tyzzer's disease of muskrats (Ondatra zibethica) were found in tissue sections from two muskrats found dead in Iowa in 1947 by Paul Errington. These findings support further the hypothesis that Errington's and Tyzzer's diseases of muskrats are a single entity.     

Candidate loci reveal genetic differentiation between temporally divergent migratory runs of Chinook salmon (Oncorhynchus tshawytscha)

Local adaptation is a dynamic process driven by selection that can vary both in space and time. One important temporal adaptation for migratory animals is the time at which individuals return to breeding sites. Chinook salmon (Oncorhynchus tshawytscha) are excellent subjects for studying the genetic basis of temporal adaptation because their high seasonal homing fidelity promotes reproductive isolation leading to the formation of local populations across diverse environments. We tested for adaptive genetic differentiation between seasonal runs of Chinook salmon using two candidate loci; the circadian rhythm gene, OtsClock1b, and Ots515NWFSC, a microsatellite locus showing sequence identity to three salmonid genes central to reproductive development. We found significant evidence for two genetically distinct migratory runs in the Feather River, California (OtsClock1b: F(ST)=0.042, P=0.02; Ots515NWFSC: F(ST)=0.058, P=0.003). In contrast, the fall and threatened spring runs are genetically homogenous based on neutral microsatellite data (F(ST)=-0.0002). Similarly, two temporally divergent migratory runs of Chinook salmon from New Zealand are genetically differentiated based on polymorphisms in the candidate loci (OtsClock1b: F(ST)=0.083, P-value=0.001; Ots515NWFSC: F(ST)=0.095, P-value=0.000). We used an individual-based assignment method to confirm that these recently diverged populations originated from a single source in California. Tests for selective neutrality indicate that OtsClock1b and Ots515NWFSC exhibit substantial departures from neutral expectations in both systems. The large F(ST )estimates could therefore be the result of directional selection. Evidence presented here suggests that OtsClock1b and Ots515NWFSC may influence migration and spawning timing of Chinook salmon in these river systems.     

Estimation of a Nonlinear Density-Dependence Parameter for Wild Turkey

Abstract: Although previous research and theory has suggested that wild turkey (Meleagris gallopavo) populations may be subject to some form of density dependence, there has been no effort to estimate and incorporate a density-dependence parameter into wild turkey population models. To estimate a functional relationship for density dependence in wild turkey, we analyzed a set of harvest-index time series from 11 state wildlife agencies. We tested for lagged correlations between annual harvest indices using partial autocorrelation analysis. We assessed the ability of the density-dependent theta-Ricker model to explain harvest indices over time relative to exponential or random walk growth models. We tested the homogeneity of the density-dependence parameter estimates (θ) from 3 different harvest indices (spring harvest no. reported harvest/effort, survey harvest/effort) and calculated a weighted average based on each estimate's variance and its estimated covariance with the other indices. To estimate the potential bias in parameter estimates from measurement error, we conducted a simulation study using the theta-Ricker with known values and lognormally distributed measurement error. Partial autocorrelation function analysis indicated that harvest indices were significantly correlated only with their value at the previous time step. The theta-Ricker model performed better than the exponential growth or random walk models for all 3 indices. Simulation of known parameters and measurement error indicated a strong positive upward bias in the density-dependent parameter estimate, with increasing measurement error. The average density-dependence estimate, corrected for measurement error ranged 0.25 ≤ θC ≤ 0.49, depending on the amount of measurement error and assumed spring harvest rate. We infer that density dependence is nonlinear in wild turkey, where growth rates are maximized at 39-42% of carrying capacity. The annual yield produced by density-dependent population growth will tend to be less than that caused by extrinsic environmental factors. This study indicates that both density-dependent and density-independent processes are important to wild turkey population growth, and we make initial suggestions on incorporating both into harvest management strategies.     

Population genetic structure of and inbreeding in an insular cattle breed, the Jersey, and its implications for genetic resource management

The Jersey is a ubiquitous and successful breed of cattle that originates from the UK Channel Island of Jersey. While the breed has been exported extensively, no imports have taken place to the island since 1789, leading to a concern regarding possible losses of genetic diversity and increased inbreeding. We have conducted the first large-scale genetic analysis of the Jersey cattle using only samples from the island. A total of 223 cattle from all parishes except one were genotyped for 12 microsatellite loci. The average number of alleles per locus and expected heterozygosity were found to be comparatively high (n(A)=4, H(e)=0.64) with respect to that observed in a number of continental breeds. Only breeds that have been upgraded and are therefore the result of admixture are clearly more variable than the Jersey. We also found a significant but limited amount of genetic differentiation between parishes (F(st)=0.013), or even between farms (F(st)=0.035) despite an apparent lack of movement. This is confirmed by the application of two recent statistical methods. A Bayesian partition analysis shows that the most probable value of K, the number of possible hidden partitions, is 1 (P approximately 0.98). K=2 has a much lower probability (P approximately 0.02) while other values are essentially zero. Similarly, we were able to show that there was no support for departure from panmixia other than due to population structure, and thus that there is sufficient background gene flow across the island to overcome local drift. Overall, it appears that the current level of genetic diversity and its distribution within the island means it is unnecessary to import unrelated genetic material to the island for management purposes.     

Oxygen supply of the brain cortex in acute nitrite hypoxia in rodents with different ecological specialization

Microhemodynamics and oxygen tension (pO₂) in the brain cortex tissues as well as the heart rate were studied in rodents with different ecological specialization during hypoxia produced by subcutaneous injection of sodium nitrite (3 mg/100 g body mass). It was shown that the blood flow in animals with low (rats) and high (muskrats) resistance to hypoxia decreased by the 30th min of the nitrite action, with its subsequent restoration to 85% and 83% of the initial level by the 60th min. The interspecies difference consisted in an increase of the brain blood flow (by 24%) in muskrats and a decrease (by 33%) in rats 15 min after the injection. In rats, simultaneously with the blood-flow dynamics, a pO₂ increase was observed in some brain cortex microareas, while in others—a pO₂ decrease 15 min after the NaNO₂ injection: meanwhile, in muskrats, at this time period a significant pO₂ decrease was observed on the background of a blood flow increase. In both animal species, the pO₂ minimal value was reached by the 45th min, while restoration almost to the initial levels—by the 60th min of the nitrite action. Changes in the rats, synchronous and unidirectional with the heart rate frequency, of the brain blood-flow, as well as tachycardia developing throughout the whole experiment in rats allow suggesting that restoration of the oxygen regime in the brain cortex microareas is provided by activation of systemic mechanisms of regulation of circulation.     

Biodegradation of chlorferon and diethylthiophosphate by consortia enriched from waste cattle dip solution

Chlorferon and diethylthiophosphate (DETP) are the hydrolysis products of coumaphos, an organophosphate pesticide. In this research, two consortia of bacterial cultures, one responsible for degrading chlorferon and the other for degrading DETP, were selectively enriched from waste cattle dip solution. The enriched cultures were used as inocula to grow biomass for biodegradation studies. For chlorferon degradation, the optimum biomass concentration was found to be 80g/L, and pH 7.5 was selected as the optimal operating pH. Chlorferon degradation was characterized by substrate inhibition kinetics with parameter values estimated to be V(m)=0.062+/-0.011mg/(g-biomass)h, K(m)=21+/-7mg/L, and K(Si)=118+/-45mg/L. For DETP degradation, the optimum biomass concentration was found to be 60g/L, and the optimum pH was in the range of 7.5-8. DETP degradation was characterized by Michaelis-Menten kinetics with parameter values estimated to be V(m)=1.52+/-0.10mg/(g-biomass)h and K(m)=610+/-106mg/L.     

ESR signal of the iron-sulfur center F(X) and its function in the homodimeric reaction center of Heliobacterium modesticaldum

Electron transfer in the membranes and the type I reaction center (RC) core protein complex isolated from Heliobacterium modesticaldum was studied by optical and ESR spectroscopy. The RC is a homodimer of PshA proteins. In the isolated membranes, illumination at 14 K led to accumulation of a stable ESR signal of the reduced iron-sulfur center F(B)(-) in the presence of dithiothreitol, and an additional 20 min illumination at 230 K induced the spin-interacting F(A)(-)/F(B)(-) signal at 14 K. During illumination at 5 K in the presence of dithionite, we detected a new transient signal with the following values: g(z)= 2.040, g(y)= 1.911, and g(x)= 1.896. The signal decayed rapidly with a 10 ms time constant after the flash excitation at 5 K and was attributed to the F(X)(-)-type center, although the signal shape was more symmetrical than that of F(X)(-) in photosystem I. In the purified RC core protein, laser excitation induced the absorption change of a special pair, P800. The flash-induced P800(+) signal recovered with a fast 2-5 ms time constant below 150 K, suggesting charge recombination with F(X)(-). Partial destruction of the RC core protein complex by a brief exposure to air increased the level of the P800(+)A(0)(-) state that gave a lifetime (t(1/2)) of 100 ns at 77 K. The reactions of F(X) and quinone were discussed on the basis of the three-dimensional structural model of RC that predicts the conserved F(X)-binding site and the quinone-binding site, which is more hydrophilic than that in the photosystem I RC.