Isolation and characterization of the female-specific protein (vitellogenin) in mature female hemolymph of the prawn Penaeus chinensis

Enantioseparation, recognition mechanisms and binding of xanthones on human serum albumin by liquid chromatography

Aim: To develop a method for enantioseparation of several chiral derivatives of xanthones (CDXs) by LC using a human serum albumin-chiral stationary phase (HSA-CSP) and screening CDX-HSA affinity. Additionally, recognition mechanisms were investigated. Materials & methods: The influence of organic modifier, buffer type, pH and ionic strength of mobile phase, and temperature were explored. The affinity was determined by measuring the retention times and further calculation of bound percentage. Chiral recognition mechanisms were investigated by docking. Results: Enantioselectivity and resolution values ranged from 1.40 to 9.16 and 1.51 to 4.97. Bound percentages ranged from 79.02 to 99.99%. Conclusion: LC systematic study and binding affinity of CDXs on HSA-CSP are presented here for the first time, expanding the applications of HSA-CSP for this class of compounds.

Identification of a common recognition center for a photoactive non-steroidal antiinflammatory drug in serum albumins of different species

Photoreactivity, proteomic and molecular dynamic simulation studies demonstrate the existence of a common recognition center for carprofen in serum albumins of different species, in the interface between subdomains IB and IIIA.

Species-dependent binding of tocainide analogues to albumin: affinity chromatography and circular dichroism study

A series of novel tocainide analogues were characterized for their HSA and RSA binding, by using high-performance liquid affinity chromatography (HPLAC) and circular dichroism (CD). In this HPLAC study, HSA and RSA were covalently immobilized to the silica matrix of HPLC columns, with a procedure that maintained unaltered the binding properties of the proteins. The tocainide analogues were ranked for their affinity to HSA and RSA on the basis of their bound fractions measured by the two albumin-based columns. This technique was also applied to characterize the high affinity binding sites of these tocainide analogues to the protein. For this purpose displacement experiments were carried out by means of increasing concentrations in the mobile phase of competitors known to bind selectively to the main binding sites of HSA. The results obtained with the immobilized proteins were confirmed by investigating the same drug-protein systems in solution by circular dichroism. The comparison of the data collected with both methodologies highlighted the dramatic effect of small differences in the amino acidic sequences of the two proteins. In fact, despite their similar primary and secondary structures, a small difference in the amino acidic sequence leads to significant differences in their three-dimensional structure reflecting their different binding capacity and their stereoselectivity. Therefore, this study confirms how it is crucial to consider the significant differences among the animal models when performing pharmacokinetic studies. It is also clear that the knowledge of serum carrier binding parameters at an early stage of drug discovery represents a great advantage that may help to save time and efforts.

Gammarus spp. in aquatic ecotoxicology and water quality assessment: toward integrated multilevel tests

The amphipod genus Gammarus is widespread and is structurally and functionally important in epigean freshwaters of the Northern Hemisphere. Its presence is crucial, because macroinvertebrate feeding is a major rate-limiting step in the processing of stream detrius. In addition, Gammarus interacts with multiple trophic levels bu functioning as prey, predator, herbivore, detritivore, and shredder. Such a broad span of ecosystem participation underlines the importance of Gammarus to pollutants and other disturbances may render it a valuable indicator for ecosystem health. This review summarizes the vast number of studies conducted with Gammarus spp. for evaluating aquatic ecotoxicology endpoints and examines the suitability of this native invertabrate species for the assessment of stream ecosystem health in the Northern Hemisphere. Numerous papers have been published on how pollutants affect gammarind behavior (i.e., mating, predator avoidance), reproduction, development, feeding activity, population structure, as well as the consequences of pollution on host-parasite, predator-prey, or native-invasive species interactions. Some biochemical and molecular biomarkers have already been established, such as the measurement of vitellogenin-like proteins, metallothioneins, alkali-labile phosphates (in proteins), and lipogenic enzyme activities for assessing endocrine distribution and detoxification mechanisms.

Characterization of vitellin from the ovaries of the banana shrimp Litopenaeus merguiensis

Vitellin (Vt) was purified from ovary extracts of mature females of the banana shrimp Litopenaeus merguiensis using DEAE-Sephacel and Superdex 200 columns. Native Vt had an apparent molecular mass of 398 kDa as determined by native PAGE and by gel filtration chromatography. Under reducing and denaturing conditions (SDS-PAGE), Vt is composed of two major subunits of 87 and 78 kDa, although some faint bands were also detected. The N-terminal 10 amino acids sequence of the 78 kDa subunit is identical to that of Litopenaeus vannamei Vt and very similar to that of Litopenaeus japonicus vitellogenin (Vg) as well as Litopenaeus semisulcatus Vt, with an identity of 89%. Anti-Vt polyclonal antibody raised against purified Vt shows a high specificity with only ovarian Vt and hemolymph Vg of vitellogenic shrimps in double immunodiffusion and Western blot assays. Vg and Vt concentrations in hemolymph, hepatopancreas and ovaries were measured by ELISA. Vg concentrations increased in the hemolymph in the early stages of ovarian development and declined in the maturation stages. As there were undetectable concentrations of Vg in the hepatopancreas while an elevation of Vg levels occurred in the hemolymph, during the time that Vt was accumulating in the ovaries during oogenesis, this would suggest that the contribution of Vg synthesized by the hepatopancreas only might be not sufficient for adequate development of the oocytes in the banana shrimp L. merguiensis during vitellogenesis.

Altered exoskeleton composition and vitellogenesis in the crustacean Gammarus sp. collected at polluted sites in the Saguenay Fjord, Quebec, Canada

Gammarus sp. individuals were collected at four intertidal sites subjected to direct sources of pollution (marinas, ferry traffic, and harbors) and at one site with no direct source of pollution. Levels of vitellogenin-like proteins (Vtg), metallothioneins (MT), alkali-labile phosphates (ALPs) in proteins, and lipogenic enzyme activities (i.e., glucose-6-dehydrogenase, isocitrate dehydrogenase, and malate enzyme) were measured in whole soft tissues. In exoskeletons, levels of pH-dependent extractable protein and chitin were determined to assess the possible impacts of pollution on exoskeleton integrity and the molting process. Results show that males were consistently heavier than females regardless of site quality but that the whole-body weight of both sexes was significantly lower at polluted sites. Females displayed either induced or decreased Vtg-like proteins at polluted sites, indicating significant changes in gametogenesis activity. MT levels were not sex dependent and tended to be induced at all impacted sites. ALP levels in acetone-fractionated proteins indicate altered phosphate mobilization at some impacted sites, where females tended to display higher ALP levels. Lipogenic enzyme activities did not vary by sex but were readily increased at impacted sites, suggesting a delay in gonad maturation rates. Exoskeleton protein characteristics revealed that the proportion of chitin in exoskeletons was a lower at most impacted site, suggesting disruption of chitin and pH-dependent protein mobilization. Principal component analysis revealed that gammarids collected at affected sites displayed substantial changes in the proportion of chitin, arthropodin, sclerotin, MTs, and intermediary glucose metabolism (glucose-6-phosphate dehydrogenase, and isocitrate dehydrogenase in soft tissues) and thus suffered from disturbed gametogenesis and exoskeleton integrity.

Shell protein characteristics and vitellogenin-like proteins in brine shrimp Artemia franciscana exposed to municipal effluent and 20-hydroxyecdysone

We developed biomarkers to monitor the endocrine-disrupting potential of contaminants and municipal effluents in aquatic arthropods. Artemia fransciscana shrimp were cultured and exposed to increasing concentrations of 20-hydroxyecdysone (20HE) and solid phase (C-8) municipal effluent extract (MEE) for 48 h at 20 degrees C. The levels of vitellogenin (Vtg)-like proteins, alkali-labile phosphates in total proteins and acetylcholinesterase (AChE) activity were determined in soft tissues. The levels of acid-soluble, alkali-soluble (sclerotin), neutral-soluble (arthropodin) proteins and chitin were determined to characterize the maturation state of shells. Both 20HE and the municipal effluent extract readily increased the total activity of acetylcholinesterase, alkali-labile phosphates in proteins and vitellogenin-like proteins in brine shrimp. In shells, 20HE and the effluent extract increased the proportion of chitin in shells and acid-soluble proteins but were not statistically significant for the latter. The proportion of sclerotin was increased by 20HE but was not changed by the effluent extract. The proportion of arthropodin was decreased by both 20HE and the effluent extract. Correlation analysis revealed that, as expected, the proportion of acid-soluble protein for biomineralisation and chitin levels were positively correlated and the proportion of arthropodin and sclerotin were negatively correlated in shells exposed to 20HE. Principal component analysis revealed that the proportion of chitin, arthropodin, sclerotin and acid-soluble proteins explained 63% of the responses. Shell protein and carbohydrate contents, controlled by the molting hormone 20HE, could be used as efficient markers for ecdysial properties of various contaminants. The municipal effluent appears to contain ecdysial-like chemicals that are capable of producing changes in shell protein composition that are similar to 20HE.

Drug affinity to immobilized target bio-polymers by high-performance liquid chromatography and capillary electrophoresis

This review addresses the use of high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) as affinity separation methods to characterise drugs or potential drugs-bio-polymer interactions. Targets for the development of new drugs such as enzymes (IMERs), receptors, and membrane proteins were immobilized on solid supports. After the insertion in the HPLC system, these immobilized bio-polymers were used for the determination of binding constants of specific ligands, substrates and inhibitors of pharmaceutical interest, by frontal analyses and zonal elution methods. The most used bio-polymer immobilization techniques and methods for assessing the amount of active immobilized protein are reported. Examples of increased stability of immobilized enzymes with reduced amount of used protein were shown and the advantages in terms of recovery for reuse, reproducibility and on-line high-throughput screening for potential ligands are evidenced. Dealing with the acquisition of relevant pharmacokinetic data, examples concerning human serum albumin binding studies are reviewed. In particular, papers are reported in which the serum carrier has been studied to monitor the enantioselective binding of chiral drugs and the mutual interaction between co-administered drugs by CE and HPLC. Finally CE, as merging techniques with very promising and interesting application of microscale analysis of drugs' binding parameters to immobilized bio-polymers is examined.

Yolk proteins during ovary and egg development of mature female freshwater crayfish (Cherax quadricarinatus)

Vitellins from ovaries and eggs at different stages of development in freshwater crayfish (Cherax quadricarinatus) were examined by chromatography, PAGE and SDS-PAGE. With these methods, two forms of vitellin (Vt1 and Vt2) were observed in ovaries and eggs (stages I and V). In ovaries in secondary vitellogenesis, native molecular mass was 470 (Vt1) and 440 (Vt2) kDa. The electrophoretic pattern of the eggs proved to be more complex. The protein molecular mass depend on the development stage of the egg: stage I, 650 kDa (Vt1) and 440 kDa (Vt2); stage V, 390 kDa (Vt1) and 340 kDa (Vt2). The identified vitellins appear to be lipo-glycocarotenoprotein. A similar vitellin polypeptide composition was observed in the two forms of vitellin from ovaries and eggs in stage V. In ovaries the SDS-PAGE analysis showed four subunits with molecular weights of approximately 180, 120, 95 and 80 kDa (Vt1 and Vt2). The polypeptide composition in the two forms of vitellins in stage I and stage III eggs were different at 195, 190, 130 and 110 kDa (Vt1) and 116 and 107 kDa (Vt2). On the other hand, in stage V eggs, 110, 95, 87 and 75 kDa (Vt1 and Vt2) were identified. Two antibodies (Ab1 and Ab2) were prepared against the purified proteins of stage V eggs and their specificity was demonstrated by radial immunoprecipitation, and Western blotting analysis. Two forms of vitellins were also found in stage V eggs after chromatography on Sepharose CL-2B column and hydroxylapatite and polyacrylamide gel electrophoresis.

Is the unique negatively charged polypeptide of crayfish yolk HDL a component of crustacean vitellin?

The yolk protein of Cherax quadricarinatus contains six major high-density lipoprotein (HDL) subunits with the approximate molecular masses of 177, 155, 106, 95, 86, and 75 kDa, of which only the 106-kDa polypeptide is negatively charged. On the basis of their molecular weights, time of appearance and disappearance, their floating density and susceptibility to enzyme degradation (by a serine proteinase), these six HDL polypeptides were classified into two subgroups. One group comprises the higher-molecular-weight compounds above 106 kDa, and the other includes the lower-molecular-weight compounds up to 95 kDa. Other than being different from the lower-molecular-weight polypeptides, the negatively charged 106-kDa polypeptide was significantly different from members of its higher-molecular-weight group belonging to a different, less abundant, yolk protein as shown by HPLC separation. Immunological studies and peptide mapping in which the 106-kDa polypeptide did not show similarity to any of the other HDL components confirmed these differences. Moreover, the amino acid composition of the 106-kDa polypeptide was different from that of known vitellin from other crustacean species. This unique negatively charged polypeptide presents an enigma as it is known to be a secondary vitellogenic-related HDL polypeptide, immunolocalized in yolk globules; however, it is different to all the other HDL polypeptides, thus presenting the question whether it is indeed a component of "classical" crustacean vitellin.

Hepatopancreas is the extraovarian site of vitellogenin synthesis in black tiger shrimp, Penaeus monodon

The site of yolk protein synthesis in crustaceans has long been a subject of controversy. The vitellogenin gene structure was partially reported only very recently in Macrobrachium rosenbergii, after which the hepatopancreas was confirmed as the extraovarian site of vitellogenin synthesis in that species. Ovaries are the most frequently reported as the site of yolk protein synthesis in penaeid shrimp. Using cDNA reversed-transcribed from mRNA isolated from the hepatopancreas of vitellogenic female shrimp, Penaeus monodon, we found that its deduced amino acid sequence had high identity of 48% with that from M. rosenbergii vitellogenin. A similar location of the intron in the sequenced region of genomic DNA was also found between these two species. We therefore concluded that the hepatopancreas the extraovarian site of vitellogenin synthesis in P. monodon in vivo. The partial structure of vitellogenin gene is presented in this study.

Determination of amino acid sequence and site of mRNA expression of four vitellins in the giant freshwater prawn, Macrobrachium rosenbergii

Four major yolk proteins, designated as vitellins (Vns) Macr-VnA, B, C, and D, were extracted from mature ovaries of Macrobrachium rosenbergii. These were purified to homogeneity by reversed-phase high performance liquid chromatography (HPLC) employing a unique separation system based on the hydrophobic properties of the Vn molecule. Using standard techniques of protein sequencing, more than 33 N-terminal and 57 internal amino acid residues were determined for each of the four Vns. The cDNA fragments encoding the four Vns were amplified by PCR using degenerate oligonucleotide primers derived from the N-terminal and internal amino acid sequences. These cDNA fragments were cloned, sequenced, and used as probes to examine the transcription of mRNAs encoding the four Vns. Significant accumulations of these mRNAs were observed in female hepatopancreas only, while mRNA expression was not detected in male hepatopancreas or any other female tissue including ovary, subepidermal adipose tissue, gill, and muscle. This is the first occasion in Crustacea in which multiple Vns were demonstrated to be synthesized simultaneously in a single tissue.

High-density lipoprotein associated with secondary vitellogenesis in the hemolymph of the crayfish Cherax quadricarinatus

The high-density lipoproteins LPI and LPII were isolated from the hemolymph of the crayfish Cherax quadricarinatus by gradient ultracentrifugation and high-performance liquid chromatography (HPLC). Both lipoproteins contained a carotenoid moiety. LPI is comprised of a single polypeptide with an approximate molecular mass of 96 kDa. LPII was composed of two similar native components, LPIIa and LPIIb, both having polypeptides of 80 and 177 kDa. Both under natural conditions and after endocrine manipulations, LPI was present in males and in females, regardless of the female reproductive stage. LPII was present only in secondary-vitellogenic females, but not during the winter reproductive arrest period. LPII was also absent from young females that had received androgenic gland implants. LPII also appeared in the hemolymph of intersex individuals from which the androgenic gland had been removed. It is therefore suggested that LPII serves as a marker indicating the onset of secondary vitellogenesis in C. quad'iariicarintus females.

Synthesis and organization of vitellogenin and vitellin molecules from the land crab Potamon potamios

We have previously reported that vitellogenin (Vg) of some female animals contained four polypeptides with molecular mass of 181, 115, 105 and 85 kDa, whereas Vg of most animals contained three polypeptides with molecular mass of 115, 105 and 85 kDa. In the present investigation, we examined whether the 181 kDa polypeptide is the precursor of 115 and 105 kDa Vg and vitellin (Vn) polypeptides. Labeling studies, using [35S]methionine on normal vitellogenic animals, showed that the radioactivity was distributed first among the 181 and 85 kDa polypeptides. SDS-PAGE analysis of purified hemolymph Vg from eyestalk ablated female animals revealed in most animals two polypeptides with an apparent molecular mass of 181 and 85 kDa. These results from in vivo experiments corroborated the view that the 115 and 105 kDa Vg and Vn polypeptides are derived from heaviest 181 kDa polypeptide. In addition it was demonstrated that hepatopancreas and ovary of Potamon potamios incubated in vitro with [35S]methionine synthesized five polypeptides with apparent molecular mass of 224, 181, 115, 105, and 85 kDa while the hepatopancreas appeared to secrete the 181, 115, 105 and 85 kDa polypeptides. The major 115, 105 and 85 kDa polypeptides were found to be components of egg Vn, while the 224 kDa polypeptide was found to be minor component of Vg and Vn from hepatopancreas and ovary extracts, respectively. We conclude that the Vn polypeptides produced by ovary are similar to those produced by hepatopancreas.

Hepatopancreas is the likely organ of vitellogenin synthesis in the freshwater prawn, Macrobrachium rosenbergii

The objective of the present study was to investigate the source of vitellogenin in the freshwater prawn, Macrobrachium rosenbergii. Ovarian development of M. rosenbergii was classified into five stages (stage I-V). Vitellin/vitellogenin was detected in the ovary and the hepatopancreas in different stages by native-PAGE and Western blotting. Two and three subunits of vitellin were observed in the ovary at the early- (I-II), mid- and late- (III-V) stages, respectively. The subunit of vitellogenin was not detected in the hepatopancreas at different stages of prawns. Hepatopancreas had positive immunocytological staining (against vitellin antibody) in different ovarian stages of prawn. Only vitellogenic oocyte but not previtellogenic oocytes and follicle cells had a positive immunocytological staining. Hepatopancreas could synthesize radiolabeled immunoreactive proteins after incubation with radiolabeled glycine on the basis of immunoprecipitation (against vitellin antiserum). Therefore, it is concluded that hepatopancreas is the most likely organ to synthesize vitellogenin in the freshwater prawn, M. rosenbergii.

Site of vitellogenin synthesis determined from a cDNA encoding a vitellogenin fragment in the freshwater giant prawn, Macrobrachium rosenbergii

Vitellogenesis is an important part of reproductive process in crustaceans, and the process is characterized by the synthesis and accumulation of yolk protein in the developing oocytes. The yolk proteins in crustaceans mainly consist of vitellogenin (Vg) and vitellin (Vn), which are respectively present in extra-oocyte tissues and intra-oocytes. The site and the process of yolk protein synthesis in crustaceans are still controversial. The synthesis site of Vg in a crustacean species, Macrobrachium rosenbergii, is determined by immunological and immunohistochemical techniques, and molecular cloning of a cDNA encoding the primary structure of Vn in this study. The hepatopancrease is clearly shown to be the synthesis site of Vg in this species. The length of Vg mRNA was estimated as about 6 kb from Northern blotting analysis. The partial primary structure of Vg gene is presented, and the post-translational processing are further discussed. For the first time, the partial primary structure of Vg gene and the synthesis site of Vg approached by molecular cloning in crustaceans are presented.

Studies of protein binding to nonpolar solutes by using zonal elution and high-performance affinity chromatography: interactions of cis- and trans-clomiphene with human serum albumin in the presence of beta-cyclodextrin

High-performance affinity chromatography and zonal elution studies were used to examine the binding that takes place between the drug clomiphene and the protein human serum albumin (HSA). Equations were derived to describe the behavior of zonal elution experiments in which a solubilizing agent is present in the mobile phase to aid in the dissolution of a competing agent or injected analyte. These equations were then used to determine the association equilibrium constants for the clomiphene/HSA system, with beta-cyclodextrin being used as a complexation agent to improve the water solubility of cis- and trans-clomiphene without affecting the nature of their binding to HSA. It was found in these studies that both cis- and trans-clomiphene have 1:1 interactions at a common binding region on HSA (association constants at pH 7.4 and 37 degrees C: cis, 7.5 x 10(6) M-1; trans, 1.3 x 10(6) M-1). Further competition experiments between cis- or trans-clomiphene and various site-selective probes indicated that the clomiphene-binding region is the same as the proposed tamoxifen site of HSA. The approach and equations used within this report are general ones that can be applied to zonal elution studies of other solute-ligand systems in which one or more of the test components have limited solubility in the desired mobile phase.

Study of human serum albumin structure by dynamic light scattering: two types of reactions under different pH and interaction with physiologically active compounds

The effect of pH and binding of ten physiologically active compounds (isoproterenol, yohimbine, propranolol, clonidine, phenylephrine, carbachol, tripeptide fMLP, diphenhydramine, chlorpromazine and atropine) on the molecular structure of human serum albumin (HSA) has been studied using the dynamic light scattering. It was found that albumin globule has the most compact configuration (Stokes diameter 59-62 A) at physiological pH 7.4. The changes in pH, both increase to 8.0 and decrease to 5.4, result in the growth of globule size to 72-81 A. At acidic shift of pH an additional peak arises in the correlation spectra caused by the light scattering on the structures with the Stokes diameters of 29-37 A. Those conform to the sizes of the albumin subdomains. The indicated peak is not displayed at basic shift of pH. The interaction with propranolol, clonidine, phenylephrine, carbachol and tripeptide fMLP which hinder adenylate cyclase (AdC) and activate Ca-polyphosphoinositide (Ca-PPI) signaling system of a cell initiates structural rearrangements similar to acidic transitions. Isoproterenol, yohimbine diphenhydramine, chlorpromazine and atropine, which activate AdC and hinder Ca-PPI, cause conformational changes of HSA similar to basic transitions.

The influence of pH alteration and pharmacological modulators of adenylate cyclase system on human serum albumin conformation

The report describes the results of a study the effect of pH and binding of six physiologically active compounds (isoproterenol, yohimbine, theophylline, propranolol, clonidine and carbachol) on the molecular structure of human serum albumin (HSA) using dynamic light scattering. It was found that the albumin globule had the most compact configuration (Stokes diameter 59-62A) at physiological pH 7.4. The changes in pH both increased to 8.0 and decreased to 5.4, resulting in the growth of globule size to 72-81A. At acidic shift of pH an additional peak arose in the correlation spectra. This peak was caused by the light scattering on the structures with the Stokes diameters of 29-37A, which conformed to the sizes of the albumin subdomains. The additional peak was not displayed at basic shift of pH. The interaction with propranolol, clonidine and carbachol, which hinder adenylate cyclase (AdC) signaling system of a cell, initiated structural rearrangements similar to acidic transitions. Isoproterenol, yohimbine and theophylline, which activate AdC, caused the conformational changes of HSA similar to basic transitions.

Isolation and characterization of the female-specific protein (vitellogenin) in mature female hemolymph of the freshwater prawn, Macrobrachium rosenbergii: comparison with ovarian vitellin

Purification and characterization of the female-specific protein (vitellogenin) from the hemolymph of mature female prawn, Macrobrachium rosenbergii, were the objectives of this study. The comparison of biochemical characteristics between vitellogenin and ovarian vitellin was also conducted. Hemolymph vitellogenin was purified with DEAE, hydroxylapatite, and another DEAE chromatographic column. The specific protein (vitellogenin) was shown in the fractions of chromatographic columns on the basis of ELISA, Western blotting, and immunoprecipitation. A purified vitellogenin was obtained with an apparent molecular weight of 700 kDa as determined by PAGE. The purified vitellogenin was considered as a lipoglycoprotein on the basis of staining data. Three subunits (170, 100, and 89 kDa) in purified vitellogenin and two subunits (100 and 89 kDa) in vitellin were detected with SDS-PAGE. Nondisulfide bonds were found in the binding of polypeptide subunits. Only the 89-kDa subunit was a glycopolypeptide in both vitellogenin and vitellin. The amino acid composition of vitellogenin differed from that of vitellin in a few amino acids. Eight amino acid sequences from the N-terminal end of 89- and 100-kDa subunits were determined and they were identical between vitellogenin and vitellin. Seven amino acid sequence from the N-terminal end of the 170-kDa subunit were also identical to the 100-kDa subunit. Purified vitellogenin was more susceptible to precipitation in a solution with low ionic strength than vitellin. This study suggests a close relationship between vitellogenin and vitellin in M. rosenbergii in their biochemical characteristics.