Aldimine to ketoamine isomerization (Amadori rearrangement) potential at the individual nonenzymic glycation sites of hemoglobin a: Preferential inhibition of glycation by nucleophiles at sites of low isomerization potential

The relative roles of the two structural aspects of nonenzymic glycation sites of hemoglobin A, namely the ease with which the amino groups could form the aldimine adducts and the propensity of the microenvironments of the respective aldimines to facilitate the Amadori rearrangement, in dictating the site selectivity of nonenzymic glycation with aldotriose has been investigated. The chemical reactivity of the amino groups of hemoglobin A forin vitro reductive glycation with aldotriose is distinct from that in the nonreductive mode. The reactivity of amino groups of hemoglobin A toward reductive glycation (i.e., propensity for aldimine formation) decreases in the order Val-1(), Val-1(), Lys-66(), Lys-61(), and Lys-16(). The overall reactivity of hemoglobin A toward nonreductive glycation decreased in the order Lys-16(), Val-1(), Lys-66(), Lys-82(), Lys-61(), and Val-1(). Since the aldimine is the common intermediate for both the reductive and nonreductive modification, the differential selectivity of protein for the two modes of glycation is clearly a reflection of the propensity of the microenvironments of nonenzymic glycation sites to facilitate the isomerization reaction (i.e., Amadori rearrangement). A semiquantitative estimate of this propensity of the microenvironment of the nonenzymic glycation sites has been obtained by comparing the nonreductive (nonenzymic) and reductive modification at individual glycation sites. The microenvironment of Lys-16() is very efficient in facilitating the rearrangement and the relative efficiency decreases in the order Lys-16(), Lys-82(), Lys-66(), Lys-61(), Val-1(), and Val-1(). The propensity of the microenvironment of Lys-16() to facilitate the Amadori rearrangement of the aldimine is about three orders of magnitude higher than that of Val-1() and is about 50 times higher than that of Val-1(). The extent of nonenzymic glycation at the individual sites is modulated by various factors, such as thepH, concentration of aldotriose, and the concentration of the protein. The nucleophiles—such as tris, glycine ethyl ester, and amino guanidine—inhibit the glycation by trapping the aldotriose. The nonenzymic glycation inhibitory power of nucleophile is directly related to its propensity to form aldimine. Thus, the extent of inhibition of nonenzymic glycation at a given site by a nucleophile directly reflects the relative role ofpK _a of the site in dictating the glycation at that site. The nonenzymic glycation of an amino group of a protein is an additive/synergestic consequence of the propensity of the site to form aldimine adducts on one hand, and the propensity of its microenvironment to facilitate the isomerization of the aldimines to ketoamines on the other. The isomerization potential of microenvironment plays the dominant role in dictating the site specificity of the nonenzymic glycation of proteins.     

13Cα and 13Cβ chemical shifts as a tool to delineate β-hairpin structures in peptides

Unravelling the factors that contribute to the formation and the stability of -sheet structure in peptides is a subject of great current interest. A -hairpin, the smallest -sheet motif, consists of two antiparallel hydrogen-bonded -strands linked by a loop region. We have performed a statistical analysis on protein -hairpins showing that the most abundant types of -hairpins, 2:2, 3:5 and 4:4, have characteristic patterns of ¹³C and ¹³C conformational shifts, as expected on the basis of their and angles. This fact strongly supports the potential value of ¹³C and ¹³C conformational shifts as a means to identify -hairpin motifs in peptides. Their usefulness was confirmed by analysing the patterns of ¹³C and ¹³C conformational shifts in 13 short peptides, 10–15 residues long, that adopt -hairpin structures in aqueous solution. Furthermore, we have investigated their potential as a method to quantify -hairpin populations in peptides.     

Binding of Amyloid Beta-Protein to Intracellular Brain Proteins in Rat and Human

Amyloid beta-protein (A), in its soluble form, is known to bind several circulatory proteins such as apolipoprotein (apo) E, apo J and transthyretin. However, the binding of A to intracellular proteins has not been studied. We have developed an overlay assay to study A binding to intracellular brain proteins. The supernatants from both rat and human brains were found to contain several proteins that bind to A 1–40 and A 1–42. No major difference was observed in the A binding-proteins from brain supernatants of patients with Alzheimer's disease and normal age-matched controls. Binding studies using shorter amyloid beta-peptides and competitive overlay assays showed that the binding site of A to brain proteins resides between 12–28 amino acid sequence of A. The presence of several intracellular A-binding (AB) proteins suggests that these proteins may either protect A from its fibrillization or alternatively promote A polymerization. Identification of these proteins and their binding affinities for A are needed to assess their potential role in the pathogenesis of Alzheimer's disease.     

Ultrastructure of four types of striated muscle fibers in the atlantic hagfish (Myxine glutinosa,L.)

Summary Four types of striated muscle fibers with distinctive ultrastructure were defined in the Atlantic hagfish (Myxine glutinosa, L.): white, intermediate, and red fibers of m. parietalis, and red fibers of m. craniovelaris.White fibers are thick, contain very few mitochondria and fat vacuoles, and possess distinct and separate myofibrils with thin Z-disks and distinct M-lines. Intermediate fibers are thinner, possess largely similar myofibrils that often are even better separated due to a higher content of fat vacuoles and especially mitochondria and glycogen granules. Red fibers of m. parietalis contain large amounts of mitochondria, fat vacuoles, and glycogen granules. Their myofibrils possess M-lines, and although branching more, the myofibrils of red fibers conform with a Fibrillenstruktur pattern like those of white and intermediate fibers. Red fibers of m. craniovelaris are very thin, possess many smaller fat vacuoles, and large amounts of mitochondria and glycogen granules. The myofibrils are significantly thinner than in m. parietalis fibers, run as quite independent well separated units, possess thicker Z-disks, and lack M-lines. Large amounts of myosatellite cells are associated with these red fibers.Triads are located near A/I-junctions in all four fiber types and occur irregularly, the density of triads being different in the various fiber types.We are indebted to Dr. Finn Walvig, Biological Station, University of Oslo, Drøbak, for supply of hagfishes, and we also wish to thank Dr. Jan K. S. Jansen, Institute of Physiology, University of Oslo, for valuable suggestions during this study.     

Conditions for high frequency embryogenesis from orange (Citrus sinensis Osb.) protoplasts

Using Trovita orange (Citrus sinensis Osb.) protoplasts isolated from 6-year-old nucellar callus, the effects of protoplast density and mannitol concentration on cell divisions and embryoid formation were examined.Somatic embryogenesis in nearly direct manner was observed only at a combination of low cell densities (4×10⁴/ml) and low mannitol concentrations (0.4 M). Two alternatives to achieve high frequency embryogenesis (70%) were to either dilute the cells to lower densities, or to do serial transfers of cells to fresh medium.Orange protoplasts (cells) showed embryogenic potential, and repression of embryogenesis occurred when protoplasts were cultured at a high density and/or under high osmotic pressure.     

Control of glycoprotein synthesis: substrate specificity of rat liver UDP-GlcNAc:Manα3R β2-N-acetylglucosaminyl-transferase I using synthetic substrate analogues

UDP-GlcNAc: Man3R 2-N-acetylglucosaminyltransferase I (GlcNAc-T I; EC 2.4.1.101) is the key enzyme in the synthesis of complex and hybrid N-glycans. Rat liver GlcNAc-T I has been purified more than 25,000-fold (M _r 42,000). TheV _max for the pure enzyme with [Man6(Man3)Man6](Man3)Man4GlcNAc4GlcNAc-Asn as substrate was 4.6 µmol min^–1 mg^–1. Structural analysis of the enzyme product by proton nuclear magnetic resonance spectroscopy proved that the enzyme adds anN-acetylglucosamine (GlcNAc) residue in 1–2 linkage to the Man3Man-terminus of the substrate. Several derivatives of Man6(Man3)Man-R, a substrate for the enzyme, were synthesized and tested as substrates and inhibitors. An unsubstituted equatorial 4-hydroxyl and an axial 2-hydroxyl on the -linked mannose of Man6(Man3)Man-R are essential for GlcNAc-T I activity. Elimination of the 4-hydroxyl of the 3-linked mannose (Man) of the substrate increases theK _M 20-fold. Modifications on the 6-linked mannose or on the core structure affect mainly theK _M and to a lesser degree theV _max, e.g., substitutions of the Man6 residue at the 2-position by GlcNAc or at the 3- and 6-positions by mannose lower theK _M, whereas various other substitutions at the 3-position increase theK _M slightly. Man6(Man3)4-O-methyl-Man4GlcNAc was found to be a weak inhibitor of GlcNAc-T I.Abbreviations BSA Bovine serum albumin - Bn benzyl - Fuc, F l-fucose - Gal, G d-galactose - GalNAc, GA N-acetyl-d-galactosamine - Glc d-glucose - GlcNAc, Gn N-acetyl-d-glucosamine - HPLC high performance liquid chromatography - Man, M d-mannose - mco 8-methoxycarbonyl-octyl, (CH₂)₈ COOOCH₃ - Me methyl - MES 2-(N-morpholino)ethanesulfonate - NMR nuclear magnetic resonance - PMSF phenylmethylsulfonylfluoride - pnp p-nitrophenyl - SDS sodium dodecyl sulfate - T transferase - Tal d-talose - Xyl d-xylose; - {0, 2 + F} Man6 (GlcNAc2Man3) Man4GlcNAc4 (Fuc6) GlcNAc - {2, 2} GlcNAc2Man6 (GlcNAc2Man3) Man4GlcNAc4GlcNAc; M₅-glycopeptide, Man6 (Man3) Man6 (Man3) Man4 GlcNAc4GlcNAc-Asn Enzymes: GlcNAc-transferase I, EC 2.4.1.101; GlcNAc-transferase II, EC 2.4.1.143; GlcNAc-transferase III, EC 2.4.1.144; GlcNAc-transferase IV, EC 2.4.1.145; GlcNAc-transferase V, UDP-GlcNAc: GlcNAc2 Man6-R (GlcNAc to Man) 6-GlcNAc-transferase; GlcNAc-transferase VI, UDP-GlcNAc: GlcNAc6(GlcNAc2) Man6-R (GlcNAc to Man) 4-GlcNAc-transferase; Core 1 3-Gal-transferase, EC 2.4.1.122; 4-Gal-transferase, EC 2.4.1.38; 3-Gal-transferase, UDP-Gal: GlcNAc-R 3-Gal-transferase; blood group i 3-GlcNAc-transferase, EC 2.4.1.149; blood group I 6-GlcNAc-transferase, UDP-GlcNAc: GlcNAc3Gal-R (GlcNAc to Gal) 6-GlcNAc-transferase.     

Presence of hybridizing DNA sequences homologous to bovine acidic and basicβ-crystallins in all classes of vertebrates

Summary The eye lens-crystallins in cow and chicken are encoded by a family of at least six genes. In order to assess the distribution of the corresponding genes among other vertebrates we hybridized -crystallin sequences (A2, A3/A1, A4, B1, B2, B3), isolated from a bovine lens cDNA library, to Southern blots on whichEcoR1-digested chromosomal DNA was blotted from different vertebrate species. These included human, chimpanzee, calf, rat, pigeon, duck, monitor lizard, toad, trout, and lamprey. Positive hybridization signals were found in the representatives of virtually all classes of vertebrates. The basic B-crystallins gave hybridization signals in more species than the acidic A ones. In monitor lizard and toad the weakest hybridization signals for basic crystallin probes were found. For acidic crystallin probes the distribution pattern was more simple; among cold-blooded vertebrates a signal for A2 was found in trout and lamprey, for A4 in trout, and for A3/A1 only in toad. The results demonstrate that the duplications leading to the -crystallin gene family occurred before or during the earliest stages of vertebrate evolution.     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

Cryptomonad biliproteins — an evolutionary perspective

Each cryptomonad strain contains only a single spectroscopic type of biliprotein. These biliproteins are isolated as 50000 kDa '₂ complexes which carry one bilin on the and three on the subunit. Six different bilins are present on the cryptomonad biliproteins, two of which (phycocyanobilin and phycoerythrobilin) also occur in cyanobacterial and rhodophytan biliproteins, while four are known only in the cryptomonads. The subunit is encoded on the chloroplast genome, whereas the subunits are encoded by a small nuclear multigene family. The subunits of all cryptomonad biliproteins, regardless of spectroscopic type, have highly conserved amino acid sequences, which show > 80% identity with those of rhodophytan phycoerythrin subunits. In contrast, cyanobacteria and red algal chloroplasts each contain several spectroscopically distinct biliproteins organized into macromolecular complexes (phycobilisomes). The data on biliproteins, as well as several other lines of evidence, indicate that the cryptomonad biliprotein antenna system is primitive and antedates that of the cyanobacteria. It is proposed that the gene encoding the cryptomonad biliprotein subunit is the ancestral gene of the gene family encoding cyanobacterial and rhodophytan biliprotein and subunits.Abbreviations Chl chlorophyll - CER chloroplast endoplasmic reticulum - SSU rRNA small subunit ribosomal RNA     

On the sufficiency of the velocity field for perception of heading

All models of self-motion from optical flow assume the instantaneous velocity field as input. We tested this assumption for human observers using random-dot displays that simulated translational and circular paths of movement by manipulating the lifetime and displacement of individual dots. For translational movement, observers were equally accurate in judging direction of heading from a velocity field with a two-frame dot life and a direction field in which the magnitudes of displacement were randomized while the radial pattern of directions was preserved, but at chance with a speed field in which the directions were randomized, preserving only magnitude. Accuracy declined with increasing noise in vector directions, but remained below 2.6° with a 90° noise envelope. Thus, the visual system uses the radial morphology of vector directions to determine translational heading and can tolerate large amounts of noise in this pattern. For circular movement, observers were equally accurate with a 2-frame velocity field, 3-frame acceleration displays, and 2-frame and 3-frame direction fields, consistent with the use of the pattern of vector directions to locate the center of rotation. The results indicate that successive independent velocity fields are sufficient for perception of translational and circular heading.     

Structure of a new nonasaccharide isolated from human milk: VI2Fuc,V4Fuc,III3Fuc-p-lacto-N-hexaose

The structure of a new nonasaccharide isolated from human milk has been investigated. By using methylation analysis, FAB-MS and¹H-and¹³C-NMR spectroscopy as basic methods of structural investigation, this oligosaccharide was identified as VI²--Fuc,V⁴-Fuc,III³--Fuc-p-lacto-n-hexaose: Fuc1-2Gal1-3[Fuc1-4]GlcNAc1-3Gal1-4[Fuc1-3]GlcNAc1-3Gal1-4Glc.Abbreviations COSY correlation spectroscope - DP degree of polymerisation - FAB-MS fast atom bombardment-mass spectrometry - HPLC high performance liquid chromatography - NMR nuclear magnetic resonance - GLC gas-liquid chromatography     

Anomeric preference of glucose utilization in rat erythrocytes

The -anomer of glucose relative to the -anomer was more rapidly metabolized into lactate by rat erythrocytes at 37° C (/ ratio = ca. 1.3): the amounts of - and -D-glucose metabolized into lactate during 3 min were 0.21 and 0.27 mol/gHb, respectively. Also, the transport of -D-glucose into erythrocytes was more rapid than that of -D-glucose: the amounts of - and -D-glucose transported into erythrocytes during 3 min were approximately 3.5 and 5.0 mol/gHb, respectively. Glucose phosphorylation by rat erythrocyte hexokinase (i.e., a possible rate-limiting step in glycolysis) occurred at higher velocities with the -anomer than with the a-anomer (/ ratio = 1.28). The Km value of hexokinase for either anomer of glucose was 53 M. The glucose concentrations in erythrocytes incubated with - and -D-glucose reached about 1 mM in 1 min, indicating that hexokinase is almost completely saturated with glucose within less than 1 min. The results suggest that glucose phosphorylation and glucose transport are major and minor determinants, respectively, for the anomeric preference of glucose utilization in rat erythrocytes.     

MHC restriction of male-antigen-specific T helper cells collaborating in antibody responses

By priming female C57BL/6 mice with syngeneic male spleen cells and enriching inguinal and paraaortic lymph node cells in long-term culture (LTC) by repeated restimulations, H-Y-specific T helper cells can be produced. In response to male spleen cells carrying I-Ab antigens these cells activate antigenexpressing B cells to secrete polyclonal antibody. Before the end of the second week in LTC it was impossible to detect any helper activity. Induction of plaque-forming cells (PFC) also requires simultaneous recognition of antigen and I-A-encoded determinants in the stimulator-responder spleen-cell population. The testing of spleen cells fromH-2 recombinant strains as stimulator-responders to anti-H-Y helper T cells of C57BL/6 origin also revealed that other genes, telomeric toI-A, control the magnitude of both specific T-cell proliferation and helper-dependent B-cell activation.     

Somatic embryogenesis in Simarouba glauca

Frequency of somatic embryogenesis from callus cultures derived from immature cotyledon explants of Simarouba glauca Linn. was highest on solid MS medium supplemented with 11.1 M benzyladenine and 13.42 M -naphthaleneacetic acid. On transfer of the somatic embryos into maturation medium containing half-strength MS medium supplemented with 1.89 M abscisic acid (ABA) and 2% (w/v)sucrose, 20–25 % of embryos germinated within 20 days of culture with distinct cotyledon, hypocotyl and radicle.     

Genetic Determination of Mental Activity Parameters in the Families of Schizophrenia Patients

Psychological parameters of mental activity (30 in total) and their genetic determination were studied in 67 families of schizophrenia patients (67 patients, 107 parent, and 30 sibs). Abnormalities of most of the examined characteristics were found in both the patients and their healthy relatives. Parameters of attention shifting and emotionality revealed the largest genetic component (25–75 and 17–98%, respectively) in all analyzed groups of relatives (probands–affected sibs, probands–healthy sibs, healthy parents–healthy children, affected parents–affected children). Significant impact of genetic factors was also found in parameters stability of attention under conditions of continuous concentration, mediated retention span productivity of voluntary retention by reproduction data, personal anxiety level, reflection of unusual social groups, and self-assessment. The relationships among the characteristics examined in the system of mental activity were established by means of cluster analysis. The results of this study can be used in medical genetic counseling for identifying subjects at high risk for schizophrenia.     

Comparative Modulation by 3α,5α and 3β,5β Neurosteroids of GABA Binding Sites During Avian Central Nervous System Development

Neurosteroids are endogenous Central Nervous System (CNS) compounds which act mainly by allosteric modulation of the GABA_A receptor complex. The presence of a 3-hydroxyl group and a 5-hydrogen atom have been found to be essential structural requirements for biological activity in mammals. In the present work we report the enhancing activity on [³H]GABA binding to its receptor sites in chick optic lobe produced by progesterone metabolites 3-hydroxy,5-pregnan-20-one (3,5-P) and 3-hydroxy,5-pregnan-20-one (3,5-P). Both steroids were found able to enhance [³H]GABA binding along ontogeny, displaying a similar profile at early developmental stages, while in adulthood 3,5-P had greater potency (EC₅₀ 0.22 M) and enhancing effect (E_max: 122%). In adult synaptic membranes, the two compounds displayed a complex interaction with the GABA_A receptor, disclosed by a Schild plot with slope below one and an incomplete displacement of 3,5-P by its 3,5 isomer. Such complexity could be related to the steroidogenic profile in avian CNS, with 5-reduced progesterone metabolites present since early development, while 3,5-P is found only in adulthood. Bearing in mind differences between avian and mammalian steroidogenic profiles and the relevance of 5-steroids in early avian development, we propose that 3,5-P, instead of the classical potent 3,5-steroids, may be the endogenous modulator of GABAergic activity in developing avian brain.     

Stimulation of non-specific resistance to tumors in the mouse using a poly(maleic-acid-styrene)-conjugated neocarzinostatin

Summary The development of non-specific resistance to tumors following stimulation with poly(maleic-acid-styrene)-conjugated neocarzinostatin (SMANCS), a polymer-conjugated derivative of neocarzinostatin, was investigated in mice. The growth of syngeneic solid tumors (Meth-A fibrosarcoma and RL 1 leukemia) inoculated into BALB/c mice was suppressed after one treatment with SMANCS at doses ranging from 0.14 mg/kg to 3.4 mg/kg i.v. 24 h before tumor implantation. Since previously observations concerning SMANCS have shown that it disappeared within 1.5 h after i.v. administration in mice and that it was inactivated quickly in plasma, SMANCS evidently inhibited tumor growth by mediating non-specific resistance. In addition, the non-specific resistance to tumors stimulated by SMANCS could be passively transferred to untreated mice by serum which was shown to contain interferon (IFN) from 12 h to 20 h after SMANCS administration. However, the resistance was not produced by serum prepared from mice at 8 h or 32 h after administration presumably because of the observation that the interferon activity was only demonstrated from 12 h to 28 h after SMANCS stimulation. When the serum specimens were treated with anti-IFN- antiserum, the antitumor activity of the sera was abrogated. However, no significant change was detected in the antitumor activity of the specimens following treatment with anti-IFN-/ antiserum. Treatment of mice with SMANCS and anti-IFN- antiserum together resulted in the elimination of the non-specific resistance to tumors. The IFN induced in the sera of mice by SMANCS was shown to be 57% IFN- and 41% IFN-/. Half of the interferon produced in SMANCS-stimulated mice could be eliminated by treatment with anti-IFN-, and treatment of SMANCS-stimulated mice with both anti-IFN- and anti-IFN-/ antisera resulted in a total absence of detectable interferon. These findings suggest that while the administration of SMANCS induces both IFN- and IFN-/ production, in this case, it is only the former which mediates the non-specific resistance to tumors.     

The stimulation of methylmercury production by decomposition of flooded birch leaves and jack pine needles

The link between methylmercury (MeHg) production and decomposition of flooded organic matter was examined using an enclosure experiment. Six plastic enclosures were filled with lake water containing low concentrations of dissolved organic carbon (146µmolL^–1) and MeHg (0.02ngL^–1) and anchored in a lake at the Experimental Lakes Area, northwestern Ontario. Either fresh birch leaves, fresh jack pine needles, or no plant tissues at all were added to enclosures. Birch leaves decomposed 2.4 times faster than jack pine needles as measured by the total carbon decomposition by-products produced in enclosures over time. However, measured net MeHg production in enclosures containing birch leaves (0.35±0.05ng per g carbon added) was five times lower than in the enclosures containing jack pine needles (1.94±0.28ng per g carbon added). These results showed that MeHg production is not solely related to rates of organic matter decomposition, and that increases in MeHg associated with flooded birch leaves and jack pine needles resulted from the production of new MeHg as opposed to leaching of MeHg already in the plant tissues during decomposition.     

Purification and immunocytochemical localization of kafirins inSorghum bicolor (L. Moench) endosperm

Summary Kafirins are the storage proteins of sorghum and are found in protein bodies in the seed endosperm. They have been classified as -, -, and -kafirins according to differences in molecular weight, solubility, and structure. The kafirins were purified, amino acid composition was determined, and immunolocalization methods were used to determine the organization of the protein bodies and distribution of kafirins throughout the endosperm. All three groups of kafirins were low in lysine. -Kafirins and -kafirins were relatively high in cysteine, and -kafirins were relatively high in methionine. Transmission electron microscopy showed that protein bodies in the peripheral endosperm were spheroid with concentric rings and few darkly stained inclusions. In contrast, protein bodies of the central endosperm were irregularly shaped with a higher proportion of darkly stained material. The light staining regions of the protein bodies are composed primarily of -kafirins with minor portions of - and -kafirins. The dark staining regions, however, are composed primarily of - and -kafirins. Immunoelectron microscopy showed that protein bodies in the peripheral endosperm contain predominantly a-kafirin with minor amounts of - and -kafirin. Central endosperm protein bodies are also predominantly -kafirin, but have a higher proportion of -kafirin and -kafirin than the peripheral endosperm protein bodies.Abbreviations GAR-HRP Goat anti-rabbit horseradish peroxidase - IgG immunoglobulin G - 2-ME 2-mercaptoethanol - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - TBS Tris buffer saline - TBS-T Tris buffer saline with Tween - TBS-T-B Tris buffer saline with Tween and bovine serum albumin - TCA trichloroacetic acid - UV ultraviolet     

On age morphological changes of males of Chydoridae (Cladocera)

Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.