Accumulation of urea in the haemolymph and ammonia excretion of Penaeus japonicus exposed to ambient nitrite

Penaeus japonicus (15.7 ± 1.4 g) were exposed individually in 30 ppt seawater to 0.01 (control), 5, 10, 20 and 50 mg/l nitrite-N for 24 hr. Haemolymph ammonia, urea, nitrite and whole shrimp ammonia-N excretion and nitrite-N uptake were then determined. Ammonia excretion of P. japonicus increased with increased ambient nitrite, and with a concomitant decrease of haemolymph ammonia, as occurring increased concentrations of nitrite. Concentrations of nitrite-N and urea-N in the haemolymph of shrimp increased with increased ambient nitrite-N. However, no urea-N excretion was observed for shrimp exposed to any nitrite treatments.     

Hemolymph oxygen content,oxyhemocyanin, protein levels and ammonia excretion in the shrimp Penaeus monodon exposed to ambient nitrite

Subadult Penaeus monodon (21.03±3.19 g) were exposed individually in sea water (30 mg·ml^-1) to 0.02 (control), 1.04, 5.02, 10.11 and 20.06 mg·l^-1 nitrite-N for 24h. Hemolymph pH, partial pressures of oxygen and carbon dioxide, bicarbonate concentration, oxyhemocyanin and protein levels, and whole animal ammonia-N excretion and nitrite-N uptake were determined. Ammonia-N excretion and hemolymph oxygen partial pressure increased, whereas hemolymph pH, HCO ₃ ^- , oxyhemocyanin, protein and the ratio of oxyhemocyanin/protein levels decreased with increasing ambient nitrite-N. It is suggested that accumulated nitrite of P. monodon following exposure to ambient nitrite causes reduction of oxyhemocyanin, protein and the ratio of oxyhemocyanin/protein in the hemolymph, and affects nitrogen metabolism and acid-base balance at low hemolymph pH.Abbreviations bw body weight - EC₅₀ concentration reducing growth rate by 50% that of controls - LC₅₀ median lethal concentration - nitrite-N nitrite concentration measured as nitrogen - PO₂ partial pressure of O₂ in hemolymph - PCO₂ partial pressure of CO₂ in hemolymph - sw sea water - ww wet weight     

Haemolymph osmolality,acid-base balance and shift of ammonotelic to ureotelic excretory pattern of Penaeus japonicus exposed to ambient ammonia

1. Urea-N and nitrite-N excretions of Penaeus japonicus (11.70 ± 2.30 g) increased, but ammonia-N excretion decreased with increased ambient ammonia-N, as they were exposed individually to 0.055 (control), 1.011, 5.121, 10.032 and 20.335 mg/l ammonia-N after 24 hr.2. Haemolymph pH, PCO₂ and osmolality of shrimp displayed an inverse linear relationship with concentration of ambient ammonia-N.3. Shrimp exposed to 10.032 mg/l ammonia-N after 24 hr significantly affected (P < 0.05) haemolymph PCO₂ and osmoregulatory capacity.4. Accumulated ammonia-N in the haemolymph of shrimp following exposure to ambient ammonia-N at 5.121 mg/l or greater caused a shift from an ammonotelic to a ureotelic pattern, and may cause catabolism of hemocyanin and protein to free amino acids to balance osmoregulation.     

Metabolic responses of the white shrimp, Penaeus vannamei, to ambient ammonia

Juvenile shrimp were individually exposed during 24 h to 0.007 (control), 0.36, 1.07, and 2.14 mmol/l total ammonia-N at 28 degrees C and 39 ppt salinity. After 22 h of ammonia-N exposure, oxygen consumption was measured for 2 h, and then hemolymph, hepatopancreas, and muscle tissues were sampled. Oxygen consumption, and levels of lactate and glycogen in the hepatopancreas increased significantly at the highest ammonia-N concentration. Concentration of oxyhemocyanin, acylglycerol, and cholesterol in hemolymph, and lactate in muscle decreased significantly in the group exposed to the highest ammonia levels. The changes observed in hemolymph and tissue metabolic fuels suggest a reduced use of carbohydrate through anaerobic metabolism and an increase in the use of lipids to satisfy the metabolic demand.     

Changes in plasma amino acid levels in a euryhaline fish exposed to different environmental salinities

Previous studies have shown that Senegalese sole is partially euryhaline in the juvenile phase, being able to adapt to a wide range of salinities in a short-time period, due to changes at the osmoregulatory and metabolic level. This study aimed to assess the effects of acclimation of sole to a wide range of salinities, with a special emphasis on the role of plasma amino acids during this process. Sole juveniles were acclimated for 2 weeks to different salinities: 5, 15, 25, 38, and 55 g L⁻¹. Plasma levels of cortisol, glucose, osmolality, and free amino acids were assessed at the end. Changes in plasma levels of cortisol, glucose, and amino acids indicate that fish reared at 5 and 55 g L⁻¹ were facing extra energy costs. Amino acids seem to play an important role during salinity acclimation, either as energy sources or as important osmolytes for cell volume regulation.     

Phosphorus fractions of crayfish haemolymph, serum and haemocyanin

Different amounts of haemolymph proteins participate in clot formation in Astacus leptodactylus and Orconectes limosus (20% and 10%, respectively), although in both species the content of proteins in haemolymph is similar. In both species the content of total phosphorus in the clot was similar (0.33-0.49%, w/w) but it was about 6 times lower in serum of O. limosus than in serum of A. leptodactylus (2.2 and 14.8 mg/100 ml, respectively). An even greater difference in phosphorus content was found in the protein precipitated from serum. In both species lipid phosphorus was predominant (77% of total haemolymph phosphorus in A. leptodactylus and 52% in O. limosus). Phospholipids were found mainly in serum. Only traces of phosphorus (0.005%) and small amounts of fatty acids were found in purified haemocyanin preparations.     

Changes in free amino acid composition in haemolymph of larvae of the wax moth,Galleria mellon ella L., during cold acclimation

• 1.1. Free amino acids were analysed in the haemolymph of Galleria mellonella larvae by HPLC chromatography with o-phthaldialdehyde (OPA)-l-thio-β-d-glucose as derivatization agent.
• 2.2. Fourteen primary amino acids were detected among which glutamine, alanine, γ-aminobutyric acid (GABA) and glycine predominated and constituted 67.7% of the amino acids found.
• 3.3. The concentration of GABA increased significantly with the age of larvae entering the wandering phase and reached a maximum during metamorphosis.
• 4.4. Analysis of cold-acclimated larvae revealed a net increase of free primary amino acids from 96 to 151.8 μmol/ml during consecutive acclimation to 0°C within 20 days and to 205.4μmol/ml during cold shock injury at 0°C (3 hr).
• 5.5. The bulk of this increase was accounted for by alanine, glycine, phenylalanine and lysine.

     

Changes in brain temperature and free amino acids in normal and protein deprived suckling rats exposed to room temperature

Previous reports on early-induced protein-calorie malnutrition (PCM) in rats have indicated alterations in the concentration of free amino acids and of protein synthesis in the brain. Recently it was shown that early-induced protein deprivation (PD) retards the development of thermoregulation. This resulted in a failure to maintain a normal rectal temperature after short exposure to room temperature (+22°C) still at the age of 20–25 days corresponding to changes seen in normal rats at an age of 10–15 days. In the present study, 20-day old PD and normal rats where examined with regard to the effect of exposure to room temperature on brain temperature and on brain free amino acids. The results show a similar reduction in brain and rectal temperature of the PD rats occuring within 30 minutes after exposure to room temperature. The reduction was in the range of 5°C. PD rats kept in room temperature for 5 hours and then allowed to recover at 32.5°C showed a slow increase in brain and rectal temperature but normal temperatures were not reached even after 1 hour. The concentration of free amino acids in the brain was examined in rats kept for 1 hour at room temperature or at 32.5°C. In the PD rats kept at 32.5°C, free aspartate and glutamate were reduced whereas taurine, GABA and glycine were increased as compared to their corresponding control rats. As a result of the reduced brain temperature in PD rats exposed to room temperature there was a reduction in free asparagine. The lability of the pool of asparagine may be related to the low levels of aspartate and glutamate in PD rats. On the basis of the present findings it is recommended that temperature-sensitive parameters are examined in PCM rats at a normal body temperature.Special Issue dedicated to Prof. Holger Hydén     

Relationship of glutamate dehydrogenase levels to free amino acids, amides and ammonia in excised oat leaves

Levels of glutamate dehydrogenase (GDH) increase 12 fold indetached oat leaves during 96 hr incubation with 15 mM ammonia.The slight elevation of GDH detected within the first 24 hrwas followed by increasing rates of enzyme production in subsequentperiods. Rapid increases in free ammonia and amino acids witha marked synthesis of glutamine and decreased of glutamate andaspartate were observed during the initial stages of ammoniumassimilation. (Received December 26, 1973; )     

Changes in ammonia and amino acid levels in the erythrocytes and plasma of carp, Cyprinus carpio, during passage through the gills

Differences in ammonia and free amino acid levels between the dorsal aorta (post-gills) and bulbus arteriosus (pre-gills) were studied in sixteen unanaesthetized carp, Cyprinus carpio , to clarify he roles of erythrocytes in inter-organ transport of these substances. Both erythrocyte and lasma ammonia concentrations decreased significantly during passage through the gills, and the erythrocyte contribution (53%) to the total net decrease of ammonia on a whole blood basis was approximately equal to that by the plasma (47%). The glutamine level in the plasma showed no significant change, but that in the erythrocytes increased slightly. There were losses of some amino acids from the plasma circulating through the gills, while significant increases were noted in the erythrocytes, i.e., changes in the concentrations of most amino acids were in opposite directions in the erythrocytes and plasma across the gills. The results of this study show that not only plasma but also erythrocytes are involved in ammonia and amino acid transportations in carp.     

Variation in the level of free amino acids during larva development of Penaeus japonicus (Crustacea, Decapoda, Penaeidae]

Variations of free amino-acids (FAA) content during the larval development of Penaeus japonicus have been studied. FAA content increases from 83 to 687 mumoles/g dry weight from egg to post-larval (20 days old: P20) development. There is a sharp increase between zoe and mysis stages, and another one between one day post-larvae (P1) and P20. After the mysis stage, free essential and non essential amino-acids evolve in a different way: the non essential FAA content, mainly glycine, increases continuously, whereas essential FAA content decreases (about 40%) from the mysis stage to metamorphosis in post-larvae (P1). FAA content evolution during larval development exhibits the same trend as the variation of the digestive enzyme activity.     

蜜蜂幼虫血淋巴游离氨基酸和微量元素含量的差异对其抗螨特性的影响

重新界定的外寄生螨类---狄斯瓦螨Varroa destructor(Anderson and Trueman),严重危害全世界的西方蜜蜂Apis mellifera。但是对其原始寄主东方蜜蜂Apis cerana不构成可见的危害。在西方蜜蜂群中,狄斯瓦螨在雄蜂房和工蜂房都能进行繁殖。在其亚洲的原始寄主东方蜜蜂群中,它们可以寄生于雄蜂和工蜂,但在工蜂房中不育。蜜蜂的血淋巴是狄斯瓦螨生存和繁殖需要摄取的惟一食物来源,推测血淋巴中的某种物质含量会影响狄斯瓦螨的繁殖。对中华蜜蜂Apis ceranaFabricius和意大利蜜蜂ApismelliferaL.工蜂和雄蜂封盖幼虫血淋巴中游离氨基酸和与营养有关的微量元素含量进行了比较,发现其存在明显差异,并推测这些差异与东方蜜蜂抗螨能力强有关。     

Survival,haemolymph osmolality and tissue water of Penaeus chinensis juveniles acclimated to different salinity and temperature levels

Survival, growth, haemolymph osmolality and tissue water of Penaeus chinensis (Osbeck) juveniles (0.11 ± 0.04 g) were investigated, after they were acclimated to 10, 20, 30 and 40 ppt from 33 ppt for 14 days at 24°C, and then acclimated to 12, 18, 24 and 30°C at each salinity for 14 days. The survival of shrimp was the lowest at 10 ppt and 12°C. Growth of shrimp increased with increased temperature in the range 12–24°C, with no significant difference among four salinity levels at 18, 24 and 30°C. Haemolymph osmolality increased with increased salinity, and decreased with increased temperature. The isosmotic point computed from the linear relationship between haemolymph osmolality and medium osmolality was 664, 632, 629 and 602 mOsm/kg which is equivalent to 25.2, 24.1, 24.0 and 23.1 ppt at 12, 18, 24 and 30°C, respectively. Tissue water decreased with increased medium osmolality and haemolymph osmolality. The slope obtained from the relationship between haemolymph osmolality and medium osmolality indicated that there is an impairment of osmoregulatory ability for the P. chinensis juveniles at 12°C.     

Purification and characterisation of a calcium-independent lectin (PjLec) from the haemolymph of the shrimp Penaeus japonicus

A natural lectin (nominated PjLec) was isolated from haemolymph of the shrimp Penaeus japonicus by affinity chromatography with fetuin-Sepharose. The result of SDS-PAGE showed that the purified PjLec protein consisted of 37kDa subunits. The native PjLec behaved as a 452kDa protein in gel filtration chromatography. Those data suggest that PjLec is composed of 12 subunits of similar molecular weight. PjLec has a broad spectrum of bacterial-agglutination activities against both Gram-positive and Gram-negative bacteria, including two Vibrio species and two other strains pathogenic for shrimp. In addition, PjLec could agglutinate all the vertebrate erythrocytes tested, and the haemagglutination was calcium-independent. The haemagglutination of PjLec was inhibited by ManNAc, Neu5A and lipopolysaccharide. Bovine submaxillary mucin, which contains mainly Neu5A, was the most potent inhibitor of PjLec (MIC of 0.0006mgml(-1)). The haemagglutination activity of PjLec was stable between pH 6 and pH 8, and was temperature-dependent. Our results suggested that PjLec may be an important humoral defence factor against bacterial infection in P. japonicus.     

Changes in free amino acid concentrations in serum,brain, and CSF throughout embryogenesis

Using the developing chick embryo as a model and a very sensitive micromethod for amino acid analysis, a complete analysis is presented of the developmental changes in free amino acid concentration in the blood, in the CSF, and in two different brain regions (optic lobe and frontal lobe) of the chick embryo (from day 4 of incubation, until day 5 post hatching). The developmental profile of Lys is the only one that is almost identical in all three compartments. The developmental profiles of the serum and of the brain are very similar for Arg and Phe, less so for Leu and Gly, and towards the end of the embryonic period, similar also for Val, Ile, Trp, and Met. The amino acid concentrations in the CSF are either much lower than in serum and brain already at the earliest stages, or they progressively decline to levels lower than those in brain and serum, most rapidly between day 6 and 8 of embryonic life. The concentrations of neuroactive amino acids (Gln, Glu, Asp, GABA, Tau, and Gly) in both brain regions begin to increase very early, and continue to rise, except Tau, which goes through a maximum at day 8. Comparative analysis of the developmental profiles of each amino acid in serum, brain, and CSF reveals that the blood supply and the cellular uptake, retention, and metabolism by neural cells are the major determinants of the free amino acid pool of the developing brain.     

Redox regulation of free amino acid levels in Arabidopsis thaliana

Abiotic stresses induce oxidative stress, which modifies the level of several metabolites including amino acids. The redox control of free amino acid profile was monitored in wild‐type and ascorbate or glutathione deficient mutant Arabidopsis thaliana plants before and after hydroponic treatment with various redox agents. Both mutations and treatments modified the size and redox state of the ascorbate (AsA) and/or glutathione (GSH) pools. The total free amino acid content was increased by AsA, GSH and H₂O₂ in all three genotypes and a very large (threefold) increase was observed in the GSH‐deficient pad2‐1 mutant after GSH treatment compared with the untreated wild‐type plants. Addition of GSH reduced the ratio of amino acids belonging to the glutamate family on a large scale and increased the relative amount of non‐proteinogenic amino acids. The latter change was because of the large increase in the content of alpha‐aminoadipate, an inhibitor of glutamatic acid (Glu) transport. Most of the treatments increased the proline (Pro) content, which effect was due to the activation of genes involved in Pro synthesis. Although all studied redox compounds influenced the amount of free amino acids and a mostly positive, very close (r > 0.9) correlation exists between these parameters, a special regulatory role of GSH could be presumed due to its more powerful effect. This may originate from the thiol/disulphide conversion or (de)glutathionylation of enzymes participating in the amino acid metabolism.