Biopterin metabolism and phenylalanine hydroxylase activity during early liver regeneration

Rat liver biopterin content and the activities of two enzymes involved in biopterin metabolism, sepiapterin reductase and dihydropteridine reductase, were not altered twenty-four hours after partial hepatectomy. This surgical procedure did, however, produce a vigorous regenerative response as verified by an increase in ornithine decarboxylase activity. The tetrahydrobiopterin-dependent activity of phenylalanine hydroxylase was increased in homogenates of regenerating liver. The pteridine requirements for the expression of this activation, and the behavior of the enzyme on calcium-phosphate cellulose columns suggest that elevated levels of cyclic adenosine monophosphate in regenerating liver induce phosphorylation and activation of phenylalanine hydroxylase. This increase in the activity of the primary enzyme of phenylalanine catabolism was interpreted as a compensatory response designed to maintain homeostasis prior to liver regeneration.     

Ornithine decarboxylase and polyamine levels are reduced in CHO cells deficient in cAMP-dependent protein kinase

A Chinese hamster ovary cell mutant with greatly reduced catalytic activity of cAMP-dependent protein kinase was compared with wild type cells having normal kinase activity for differences in biosynthesis, uptake and conjugation of polyamines. The inducibility of ornithine decarboxylase in response to cAMP, serum, human chorionic gonadotropin, asparagine and phorbol esters was greatly reduced in the mutant cells. Putrescine, spermidine and spermine levels rose 2–6 fold in wild type cells but in kinase mutant cells the basal and stimulated levels were generally lower. The cellular uptake and conjugation of radiolabelled putrescine and spermidine were reduced 5–10 fold in the kinase mutant cells. These results provide further evidence of the positive regulatory control exerted by cAMP-dependent protein kinase on polyamine biosynthesis.     

Simultaneous Determination of Serotonin, 5-Hydroxyindoleacetic Acid, 3,4-Dihydroxyphenylacetic Acid and Homovanillic Acid by High Performance Liquid Chromatography with Electrochemical Detection

A rapid and highly sensitive procedure for simultaneous determination of serotonin, 5-hydroxyindoleacetic acid, 3,4-dihydroxyphenylacetic acid and homovanillic acid is described. After precipitation of proteins with perchloric acid the samples are applied directly to a high performance liquid chromatograph, with electrochemical detection. As little as 20 pg of serotonin, 5-hydroxyindoleacetic acid, and 3,4-dihydroxyphenylacetic acid and 200 pg of homovanillic acid can be detected. One chromatographic run requires less than 10 min.     

Structure determination and synthesis of lysine isopeptides influencing on cell proliferation

The clavicepamines are lysine-rich basic proteins isolated from saprophytic culture of ergot (Claviceps purpurea), having human pharmacological importance. Based on structure determinations, it was demonstrated that the ϵ-lysine (poly)peptides are the fundamental structural units of clavicepamines. To study the relationship between chemical structure and biological effect, solution and solid-phase synthesis of lysine isopeptides were performed. Poly-ϵ-lysines were synthesized with polycondensation via application of p-nitrophenylester temporarily protecting groups together with simultaneous activation. The biological investigations of poly-ϵ-lysines showed a cell-proliferation retarding effect, so they inhibit growth of some animal tumors, practically without toxic side effects. © 1997 John Wiley & Sons, Inc. Biopoly 42: 305–318, 1997     

Effect of feeding frequency as a rearing system on biological performance,survival, body chemical composition and economic efficiency of Asian seabass Lates calcarifer (Bloch, 1790) reared under controlled environmental conditions

A 70-day rearing trial was done to determine the optimal frequency of feeding on growth performance (GP), feed conversion rate (FCR), cannibalism, survival rate (SR), body chemical composition and economic efficiency of the Asian sea bass. This study tested four different treatments of feeding frequencies (FF), once (T1), twice (T2), three times (T3), and four times (T4) per day. An average initial weight of Asian sea bass fry was 0.2 g (SD = ±0.12) were stocked 10 individuals per m³ (9.14 m × 1.82 m × 1.22 m, L × W × H; water depth 0.61 m) with two replicates per treatment (4 × 2 = 8). Fry were fed a mixture of larval commercial feed and shrimp with a pellet diet containing (46% CP). Initially, the feeding rate of 8% biomass per day was further adjusted according to fish biomass on a weekly basis. Results showed that, the FF significantly affected (p < 0.05) on growth indictors and survival rate (SR). Specifically fry fed three times a day (T3) had the best FBW, FL, SGR, ADWG and FCR followed by T4 and T2 while fry fed one time a day was the lowest in these parameters. Also, VSI, HSI and CF (k) significantly differed among the treatments. The fish whole body content of protein, moisture and ash did not significantly (p < 0.05) be affected by feeding frequency, but lipid content differed and both T3, T4 were the highest. It could be concluded that, increasing FF up to three times a day had a positive effect on weight gain, survival rate and feed utilization of Lates calcarifer. The second degree polynomial regression indicates that fed three times a day is optimum for best growth performance and survival for Asian sea bass.     

Enantioselective analysis of albendazole sulfoxide in plasma using the chiral stationary phase

We present a method for the enantioselective analysis of albendazole sulfoxide (ABZSO) in plasma for application in clinical pharmacokinetic studies. ABZSO enantiomers were separated on a 5-μm Chiralcel OB-H® column (4.6 × 150 mm) using hexane:ethanol (93:7, v/v) as the mobile phase and fluorescence detection. ABZSO was extracted with chloroform:isopropanol (8:2, v/v) from 500-μl aliquots of acidified plasma, with full drug recovery. The proposed method presented quantitation limits of 20 ng/ml for (−)ABZSO and 50 ng/ml for (+)ABZSO and was linear up to a concentration of 5,000 ng/ml of each enantiomer. Chirality 9:722–726, 1997. © 1997 Wiley-Liss, Inc.     

Improving hydration in elite male footballers during a national team training camp – an observational case study

[Purpose] The purpose of this study was to (i) assess hydration levels in elite male football players during a national team training camp before and during qualifying matches, (ii) evaluate the effect of coaching strategies for hydration based on feedback from hydration monitoring, and (iii) assess possible relationships between hydration status and training load or wellness markers.[Methods] Thirty-one male players (age 27±4 yrs; height 185±6 cm; weight 82.9±6.7 kg; body fat 10.4±2.3%) representing a national team from the Union of European Football Associations (UEFA) participated. The players were studied during three different national team training camps related to the UEFA Nations League tournament. Urine specific gravity (U_SG) was measured to assess hydration status. During all camps, the players were actively coached on improving strategies for hydration and given individual feedback on their test results. The training load was measured using GPS technology, and wellness questionnaires were completed.[Results] U_SG decreased progressively and significantly (p<0.005) during camp 1 and hydration status improved over the three camps, with fewer dehydrated and more well-hydrated players identified during the last part of camp 3. Significantly (p<0.05) higher U_SG values were observed 2 days prior to a match (MD-2) than on match day (MD); consequently, 52% of the players were dehydrated on MD-2 and only 6% on MD. No correlations were observed between hydration status and training load or wellness markers.[Conclusion] Dehydration is a challenge in elite male football, but continuous monitoring of hydration status and coaching on hydration strategies can lead to major improvements and reduce the degree of dehydration.     

Foraging strategies,craniodental traits,and interaction in the bite force of Neotropical frugivorous bats (Phyllostomidae: Stenodermatinae)

1. Bats in the family Phyllostomidae exhibit great diversity in skull size and morphology that reflects the degree of resource division and ecological overlap in the group. In particular, the subfamily Stenodermatinae has high morphological diversification associated with cranial and mandibular traits that are associated with the ability to consume the full range of available fruits (soft and hard).
2. We analyzed craniodental traits and their relationship to the bite force in 343 specimens distributed in seven species of stenodermatine bats with two foraging strategies: nomadic and sedentary frugivory. We evaluated 19 traits related to feeding and bite force in live animals by correcting bite force with body size.
3. We used a generalized linear model (GLM) and post hoc tests to determine possible relationships and differences between cranial traits, species, and sex. We also used Blomberg''s K to measure the phylogenetic signal and phylogenetic generalized least‐squares (PGLS) to ensure the phylogenetic independence of the traits.
4. We found that smaller nomadic species, A. anderseni and A. phaeotis , have a similar bite force to the large species A. planirostris and A. lituratus; furthermore, P. helleri registered a bite force similar to that of the sedentary bat, S. giannae. Our study determined that all the features of the mandible and most of the traits of the skull have a low phylogenetic signal. Through the PGLS, we found that the diet and several cranial features (mandibular toothrow length, dentary length, braincase breadth, mastoid breadth, greatest length of skull, condylo‐incisive length, and condylo‐canine length) determined bite force performance among Stenodermatiane.
5. Our results reinforce that skull size is a determining factor in the bite force, but also emphasize the importance of its relationships with morphology, ecology, and phylogeny of the species, which gives us a better understanding of the evolutionary adaptions of this highly diverse Neotropical bat group.

     

Flowering dynamics of Orchis morio L. and Herminium monorchis (L.) R.Br, at two sites in eastern England

Information taken from two long-term demographic studies on Orchis morio L. and Herminium monorchis (L.) R.Br, is used to explore some of the factors which influence flowering. The proportion of plants which flowered each year varied considerably between species, flowering in O. morio exceeding 40% in all years except one over an 18 year period; over a 30 year period (1966–95), the number of plants of Herminium in flower never exceeded 36% of the population and no inflorescences were produced in 1977 and 1991. The relationship between flowering in Herminium in a given year and the monthly rainfall and temperature for the current and 3 previous years was analysed using logistic regression. Best fits were obtained using data for the summer months in the previous year, with an increasing flowering rate with rainfall and a decline with temperature. It is hypothesized that drought and high temperatures in the summer reduce leaf area and cause premature senescence and the death of leaves, with the result that not enough carbohydrates are stored to enable plants to support or initiate inflorescences the following year. For species such as Orchis morio which produce leaves in the autumn and remain green, summer drought causes no problems as they have no above ground organs. Factors which influence flowering in this species are as yet unknown.     

No trade-off between sprinting and climbing in two populations of the Lizard Podarcis hispanica (Reptilia: Lacertidae).

Biomechanical reflections suggest that lizards that have specialized in running should differ in parts of their morphological design from lizards that have specialized in climbing. Moreover, adaptation in one direction may conflict with performance in the other. We tested this assumed trade-off by measuring climbing and running performance in two subspecies of the Mediterranean lizard Poaarcis hispanica. One subspecies, P. h. atrata , inhabits a number of small islets near the Spanish coast. It is mainly ground dwelling. The other subspecies, P. h. hispanica , was sampled on the mainland of Spain. It frequendy occupies vertical elements within its habitat. Our data do not support the notion of a trade-off between both types of locomotion. Individuals of P. h. hispanica both run and climb faster than those of P. h. atrata. There is no difference between subspecies in ability to cling onto tilted substrates. Predictions on the morphology of both subspecies, inspired by biomechanical arguments, are not supported by our measurements.