Depolarization exposes the voltage sensor of the sodium channels to the extracellular region

Summary Two domains of Na channels were mapped with site-specific antibodies raised in rabbit against synthetic peptides corresponding to a part of the voltage sensor of internal repeat 1C ₁ ⁺ (amino acids 210–223) and to a region designated dipole (amino acids 1690–1699) of eel electroplax sodium channels. The antibodies bind to their respective domains in both purified and membrane-bound channels and immunoprecipitate the channels from eel electroplax and rat brain synaptosomes.Anti-C ₁ ⁺ depresses the action potential of rat sciatic nerve in a concentration-dependent way. It binds to the external side of rat brain synaptosomal vesicle, and its binding is potentiated by depolarization. Anti-dipole binds to the inner side of the vesicle, and the binding is inhibited by depolarization.We are most grateful to Dr. M.T. Tosteson (Harvard Medical School) for providing us with samples of the S₄IV peptides. We wish to express our gratitude to Drs. D. Gordon (Hebrew University) and A. Safran (The Weizmann Institute) for helping in the immunoprecipitation procedure, to Drs. H. Rahamimoff (Hebrew University) and A. Barzilai (Columbia University) for advising us with the vesicle experiments, to Drs. D. Kassel and M. Gavish (Technion) for many fruitful discussions, and to Dr. Y. Palti (Technion) for discussions of electric field and suggesting the dipole peptide. This work was supported by a basic research fund (BRF) of The Israel Academy of Sciences #430.87 (H.M. and G.S.), a BSF Grant #84-00367 (H.M.) and The Henry Gutwirt Fund for the Promotion of Research-Technion VPR Fund #184-0093 (H.M.).     

A multivariate study of the relationship between the genetic code and the physical-chemical properties of amino acids

Summary The 20 naturally occurring amino acids are characterized by 20 variables: pK_{NH 2}, pK_COOH, pI, molecular weight, substituent van der Waals volume, seven¹H and¹³C nuclear magnetic resonance shift variables, and eight hydrophobicity-hydrophilicity scales. The 20-dimensional data set is reduced to a few new dimensions by principal components analysis. The three first principal components reveal relationships between the properties of the amino acids and the genetic code. Thus the amino acids coded for by adenosine (A), uracil (U), or cytosine (C) in their second codon position (corresponding to U, A, or G in the second anticodon position) are grouped in these components. No grouping was detected for the amino acids coded for by guanine (G) in the second codon position (corresponding to C in the second anticodon position). The results show that a relationship exists between the physical-chemical properties of the amino acids and which of the A (U), U (A), or C (G) nucleotide is used in the second codon (anticodon) position. The amino acids coded for by G (C) in the second codon (anticodon) position do not participate in this relationship.     

Methylmercury's chemistry: From the environment to the mammalian brain

Methylmercury is a neurotoxicant that is found in fish and rice. MeHg's toxicity is mediated by blockage of -SH and -SeH groups of proteins. However, the identification of MeHg's targets is elusive. Here we focus on the chemistry of MeHg in the abiotic and biotic environment. The toxicological chemistry of MeHg is complex in metazoans, but at the atomic level it can be explained by exchange reactions of MeHg bound to –S(e)H with another free –S(e)H group (R¹S(e)-HgMe + R²-S(e)H ↔ R¹S(e)H + R²-S(e)-HgMe). This reaction was first studied by professor Rabenstein and here it is referred as the “Rabenstein's Reaction”. The absorption, distribution, and excretion of MeHg in the environment and in the body of animals will be dictated by Rabenstein's reactions. The affinity of MeHg by thiol and selenol groups and the exchange of MeHg by Rabenstein's Reaction (which is a diffusion controlled reaction) dictates MeHg's neurotoxicity. However, it is important to emphasize that the MeHg exchange reaction velocity with different types of thiol- and selenol-containing proteins will also depend on protein-specific structural and thermodynamical factors. New experimental approaches and detailed studies about the Rabenstein's reaction between MeHg with low molecular mass thiol (LMM-SH) molecules (cysteine, GSH, acetyl-CoA, lipoate, homocysteine) with abundant high molecular mass thiol (HMM-SH) molecules (albumin, hemoglobin) and HMM-SeH (GPxs, Selenoprotein P, TrxR1-3) are needed. The study of MeHg migration from –S(e)-Hg- bonds to free –S(e)H groups (Rabenstein's Reaction) in pure chemical systems and neural cells (with special emphasis to the LMM-SH and HMM-S(e)H molecules cited above) will be critical to developing realistic constants to be used in silico models that will predict the distribution of MeHg in humans.     

Distribution of living planktonic foraminifera in the Ross Sea and the Pacific sector of the Southern Ocean (Antarctica)

In order to determine the factors controlling the distribution of planktonic foraminifera as a proxy for reconstruction of paleoenvironments, we present data on live assemblages collected in the Southern Ocean. Plankton tows and hydrographic measurements were taken in the upper 400 m of the water column at different sites in the Ross Sea (site B) and at the Polar Front of the Pacific Ocean (site O) during austral summers from 1998 to 2003.Based on qualitative micropaleontological observations we discriminated between Neogloboquadrina pachyderma dextral (dex) and N. pachyderma sinistral (sin). In addition for N. pachyderma (sin) we distinguished four morphs: the first one (1) has a thickened test and depressed sutures; the second morph (2) is represented by specimens characterized by a subspheric and heavily encrusted test; the third morph (3) has a thin and lobate walled test; the fourth one (4) represent the juvenile stage of N. pachyderma (sin) and is characterized by a smaller average size.The microfauna collected in the Ross Sea (site B) is characterized by the dominance of N. pachyderma (sin) (morphs 1 and 2), whereas low occurrences of Turborotalia quinqueloba, N. pachyderma (dex) and Neogloboquadrina dutertrei were noted in the first 50 m of the water column. The water column at this station is characterized by a marked and shallow stratification and a marked thermocline during the sampling season.At the ocean station (site O), the assemblage shows increasing diversification: T. quinqueloba, G. bulloides, N. pachyderma (dex) and few specimens of Globigerinita uvula characterize the planktonic microfauna. There is a predominance of non-encrusted morphs and juvenile specimens (3 and 4). At this station the mixed surface layer is deeper than in the Ross Sea (60–70 m), the pycnocline and the thermocline less marked.The depth and the intensity of the Deep Chlorophyll Maximum (DCM) influence foraminiferal distribution: N. pachyderma (sin) shows abundance peaks at or just below the DCM while G. bulloides peaks above the DCM. Coiling direction of N. pachyderma seems to be not controlled exclusively by Sea Surface Temperature (SST): probably the two coiling types are genetically different.Results document that diversity of planktonic foraminifera, number of specimens and variations in test morphology are related to regional differences in water properties (temperature, salinity, and DCM depth).     

Purification of the sperm-binding factor from the egg of the sea urchin,Hemicentrotus pulcherrimus

The substance which seems to be responsible for the sperm-binding at fertilization was successfully purified from unfertilized eggs of the sea urchin, $\text{Hemicentrotus pulcherrimus}$. It completely cancelled the fertilizing capacity only of homologous sperm without reducing their motility. The antiserum against this substance made only homologous eggs incapable of binding sperm. The methods employed for purification were (1) extraction by urea, (2) fractionation by calcium acetate, (3) salting-out by ammonium sulfate, (4) gel filtration and (5) ion-exchange chromatography. This substance was electrophoresed on cellulose-acetate strip as a single band which was stained with Amido Black, and could not be split by 6 M guanidine hydrochloride.     

Transformation of the glucocorticoid receptor in the cell-free cytosol of the neural retina of the chick embryo: Changes in the size and charge of the receptor complex during transformation suggest a multistage process

The physicochemical properties of the glucocorticoid receptors (GR), and the molecular changes induced during their transformation in the cell-free cytosol of the neural retina of the chick embryo, were investigated. The surface charge of the various size forms of the GR complex was determined on gel filtration and/or glycerol density gradient-isolated GR, by electrofocusing under nondenaturing conditions. The nontransformed molybdate-stabilized GR in hypotonic buffer (containing PMSF) appears as a 350 kilodalton (kDa) complex (Rs = 8.6 nm, S = 9.5), with an apparent pI value (pI') of 4.4 ± 0.1. The GRs in heat or salt-activated cytosols appear as a 90 kDa hormone-receptor complex (Rs = 5.6 ± 0.2, S = 3.9 ± 0.1), which is resolved as a major peak with a pI' value of 6.2 ± 0.1 and a minor peak with a pI' value of 5.4. The transformation of the 350 kDa oligomer to the 90 kDa monomer occurs in three stages. Two distinct dissociation steps were induced by 0.4 M KCl: (a) the dissociation of the 350 kDa complex to a 170 kDa complex (Rs = 7.8 ± 0.2, S = 5.1 ± 0.2), exhibiting a pI' value of 5.6 ± 0.2, induced by salt and not inhibited by molybdate; and (b) the dissociation of the 170 kDa complex to the 102 kDa complex (Rs = 5.6 ± 0.2, S = 4.4), also exhibiting a pI' value of 5.6 ± 0.2, which is blocked by molybdate. The third step, the transition of the 102 kDa complex to the activated (nuclear-like), 90 kDa form, is dependent on cytosolic factors. It is induced in the isotonic milieu by physiological temperatures, and in the cold by exposing the crude cytosol to 0.4 M KCl. The nature of this cytosolic processing step is unknown. It occurs in the presence of PMSF, which presumably inhibits proteolytic GR degrActation in the cytosol of the neural retina. Activated GR complexes tend to aggregate. Molybdate inhibits activation-induced GR-aggregation.     

Movement of Ions and Change in the Electrical Potential Profile across the Membrane of the Rhodopseudomonas sphaeroides Chromatophore Studied by the Absorbance Change of Carotenoid

The relationship between the light-induced movements of electronsand ions and the change in the electrical potential profileacross the chromatophore membranes of a green mutant of Rhodopseudomonassphaeroides was studied by measuring the carotenoid absorbancechange. The light-induced absorbance change of the carotenoid, i.e.,the change of electrical field within the membrane, was shownto be affected by the following factors: (1) the formation ofa membrane potential by the electrogenic electron transfer;(2) the decay of the membrane potential due to the electrophoreticmovements of ions; (3) the development of a diffusion potentialinduced by the ion movements; and (4) the change of surfacepotential of the inner surface of the chromatophore membranedue to the proton uptake. The kinetics of the absorbance change of carotenoid during illuminationwere semiquantitatively explained by considering these factors,and the light-induced change in the electrical potential profileacross the membrane was estimated under various conditions. ¹ Present address: National Institute for Basic Biology, Okazaki444, Japan. (Received October 21, 1981; Accepted March 18, 1982)     

Role of the Ca-pectates on the accumulation of heavy metals in the root apoplasm

In order to better understand the processes that regulate the accumulation in the apoplasm of heavy metals and their mobilization by the plant metabolites it is essential to study the mechanisms that regulate the interactions between metal ions and pectins. In such a context, the sorption of Cd(II), Zn(II), Cu(II) and Pb(II) from single and multi-metal solutions, by a Ca-polygalacturonate gel with a degree of esterification of 18.0 (PGAM₁) and 65.5% (PGAM₂) was studied in the 3.0–6.0 pH range in the presence of CaCl₂ 2.5 mM. The sorption of Cr(III) from single metal solution was also considered. The results show that the amount of each metal ion sorbed increases with increasing the initial metal ion concentration and pH. The data from the single metal solution tests show that at pH 6.0 the affinity of the metal ions towards the PGAM₁ matrix follows the order: Cr(III) > Cu(II) ? Pb(II) ? Zn(II) ? Cd(II). The simultaneous sorption of the bivalent metal ions by the PGAM₁ gels indicates that Pb(II) is selectively sorbed. The FT-IR spectra show that the carboxylate groups are mainly responsible for the metal ion coordination. The ability of PGAM₂ to accumulate Cr(III), Cu(II), and Pb(II) was lower than that found in the PGAM₁ systems whereas the sorption of Zn(II) and Cd(II) was negligible.     

Recombinant fragment 44–77 of the pigment epithelium-derived factor prevents the development of the pathological cornea neovascularization

The pigment epithelium-derived factor (PEDF), a secreted 50 kDa glycoprotein, is one of the most potent endogenous inhibitors of angiogenesis. The fragment 44–77 of PEDF possesses the antiangiogenic properties of the full-sized protein and is a potential drug candidate for the treatment of diseases of visual organs accompanied by pathological neovascularization. An effective biotechnological method for the large-scale production of the PEDF (44–77) fragment as part of the fusion protein with the SspDnaB intein has been developed. The hybrid protein was produced in Escherichia coli bacterial cells in the form of inclusion bodies, solubilized, and subjected to autocatalytic cleavage with the release of the PEDF (44–77) fragment (reaction yield 77%). The target peptide was separated from the intein by tangential ultrafiltration. The final purification of PEDF (44–77) was performed by reversed-phase HPLC. The yield of the target peptide (purity 99%) was 65 mg per 1 l of culture. The antiangiogenic activity of the peptide was confirmed in vitro using mouse endothelial cells SVEC-4-10. It was found that the preparation at a concentration of 1 nM suppresses the proliferation of endothelial cells by 53% and inhibits the formation of tube-like structures by endothelial cells. The ability of the recombinant PEDF (44–77) to block the initial stages of angiogenesis was shown using an experimental model of rabbit corneal neovascularization.     

Neurophysiological mechanisms underlying habituation of the tentacle retraction reflex in the land slug Ariolimax

Habituation of the tentacle retraction reflex was studied at the following response levels: (1) Muscle tension elicited in the tentacle retractor muscle by repeated stimulation of a cerebral nerve (at 60-sec intervals) declined in parallel with evoked activity of the largest unit in the tentacle retractor nerve. (2) The largest unit in the tentacle retractor nerve (L₄) showed spontaneous recovery and dishabituation. The rate of response decrement was inversely related to the strength of stimulus, and an optimal interstimulus interval ca. 60 s was found. Retention of habituation for 24 h was exhibited. (3) The major retractor motoneurons (L₂, L₃, L₄) all showed habituation, dishabituation, and spontaneous recovery. The decline of L₄ activity was parallelled by a decline in muscle response. (4) Compound EPSPs elicited in the retractor motoneurons by stimulation of sensory pathways showed habituation and dishabituation. (5) Unitary EPSPs elicited by stimulation of cerebral nerves and connectives with minimal stimulus strengths also showed habituation and were unaffected by spontaneously occurring EPSPs. Dishabituation by another pathway was also shown. (6) Depolarization of L₄ by a constant current produced spike trains of constant firing rate and evoked a constant level of muscle tension in repeated trials, suggesting the absence of habituation in a peripheral nerve net or at the neuromuscular junction.     

Recognition of the Structural Distortions at the Junctions Between B and Z Segments in Negatively Supercoiled DNA by Osmium Tetroxide

Abstract

It has been shown for the first time that conformational junction between contiguous right- handed B and left-handed Z segments can be recognized by a chemical probe. Plasmid pRW751 containing (dC-dG)₁₃ and (dC-dG)₁₆ blocks was treated with osmium tetroxide, pyridine (a reagent known to be single-strand selective) at physiological ionic conditions (0.1 and 0.2 M NaCl) and neutral pH. Mapping of the osmium binding sites by restriction enzyme digestion followed by nuclease SI cleavage has revealed selective binding of osmium at, or near to, the end of the (dC-dG)_n segments proximal to the 95 bp lac sequence. The junction of the shorter (dC-dG)₁₃ segment was modified to a substantially greater extent than that of the longer segment. Partial inhibition of DNA cleavage by BamHI was observed at the restriction sites neighbouring to the both (dC-dG)_n segments as a result of DNA modification by osmium tetroxide. The site-selective modification occurred only in supercoiled and not in relaxed molecules. Differences in the sensitivity of the B/Z junctions in pRW751 to the osmium tetroxide were explained by different structural features of these junctions.     

Effect of anxiety on the function of the cardiorespiratory system

The effects of anxiety on the external respiration system and respiratory sinus arrhythmia (RSA) were studied in healthy subjects in real-life conditions. Changes in external respiration parameters and heart rate variability (HRV) in students going to take their end-of-term exams were assessed relative to a midterm period, and the cardiorespiratory system was monitored in a longitudinal study for 50 days. The function of the cardiorespiratory system was characterized by measuring external respiration parameters and calculating HRV parameters. State anxiety (SA) was assessed using Spielberger’s scale. An increase in SA before an exam was accompanied by a higher breathing rate, a higher tidal volume, and lower HRV indices, especially those related to respiratory sinus arrhythmia (HF and HF _norm). The changes in the parameters depended on the increase in SA. A negative correlation was observed between midterm HF and pre-exam SA. The longitudinal study revealed a distinct negative correlation between respiratory sinus arrhythmia parameters and peak expiratory flow (PEF) and a positive correlation between SA and PEF in the majority of subjects. Changes in cardiorespiratory parameters depended on the changes in SA in the longitudinal study. An increase in SA was accompanied by substantial changes in respiratory sinus arrhythmia (RAS) and external respiration parameters, and their correlation was assumed to indicate that modification of parasympathetic activity plays a leading role in increasing PEF.     

An Informational Approach to the Analysis of the Low-Frequency Neuronal Impulse Activity in the Rostral Hypothalamus

Statistical analysis of the low-frequency (1.0 sec^-1 and lower) neuronal impulse activity (IA) meets a few fundamental difficulties. Among them, the most significant is the small number of measurements (interspike intervals) recorded within an acceptable analysis epoch. In our study, we examined the possibility of using the normalized (by its maximum value) informational entropy (Hn) for estimation of the significance of changes in the IA generated by low-frequency neurons of the rostral hypothalamus after electrical stimulation of the prefrontal cortex. We compared the efficiencies of using the U-test (Kolmogorov–Mann–Whitney) and Hn estimate for the analysis of the same samples of neuronal responses. The results allow us to conclude that Hn is a significantly more acceptable estimate for detection of stimulation-induced modifications of the IA generated by low-frequency neurons, as compared with the U-test. The direction of shifts in the Hn value makes it possible to estimate the pattern of neuronal response. This value reflects the state of the neuron and correlates with the type of neuronal responses.     

Inhibition of Fatty Acid Amidohydrolase,the Enzyme Responsible for the Metabolism of the Endocannabinoid Anandamide,by Analogues of Arachidonoyl-serotonin

Arachidonoyl-serotonin inhibits in a mixed-type manner the metabolism of the endocannabinoid anandamide by the enzyme fatty acid amidohydrolase. In the present study, compounds related to arachidonoyl-serotonin have been synthesised and investigated for their ability to inhibit anandamide hydrolysis by this enzyme in rat brain homogenates. Removal of the 5-hydroxy from the serotonin head group of arachidonoyl-serotonin produced a compound (N-arachidonoyltryptamine) that was a 2.3-fold weaker inhibitor of anandamide hydrolysis, but which also produced its inhibition by a mixed-type manner (K_i(slope) 1.3 µM; K_i(intercept) 44 µM). Replacement of the amide linkage in this compound by an ester group further reduced the potency. In contrast, replacement of the arachidonoyl side chain by a linolenoyl side chain did not affect the observed potency. N-(Fur-3-ylmethyl) arachidonamide (UCM707), N-(fur-3-ylmethyl)linolenamide and N-(fur-3-ylmethyl)oleamide inhibited anandamide hydrolysis with pI50 values of 4.53, 5.36 and 5.25, respectively. The linolenamide derivative was also found to be a mixed-type inhibitor. It is concluded that the 5-hydroxy group of arachidonoyl-serotonin contributes to, but is not essential for, inhibitory potency at fatty acid amidohydrolase.     

Evidence for the presence of enkephalins in the heart

Extracts of guinea pig hearts were subjected to high performance liquid chromatography (HPLC) and the eluted fractions monitored by radioimmunoassays (RIA) for their content of leucine⁵-enkephalin (Leu-ENK) and methionine⁵ enkephalin (Met-ENK). Distinct peaks of both Leu-ENK and Met-ENK immunoreactivity were found corresponding to the position of synthetic Leu-ENK and Met-ENK respectively. The ratio of Leu-ENK to Met-ENK content was about 1:4. Chemical sympathectomy with 6-hydroxydopamine (6-OH-DA) produced a dramatic fall in noradrenaline content of the heart by more than 99%, whereas the concentration in Leu-ENK was reduced by only 70%. The Leu-ENK content of the adrenal glands was not affected by this treatment. These observations point to an enkephalinergic innervation of the heart which appears to be mainly of sympathetic origin. The results suggest the participation of enkephalins in cardiac reflex mechanisms.     

Partial characterization of the glucose transport activity in the golgi-rich fraction of fat cells

The glucose transport activity solubilized from the basal and plus insulin forms of the Golgi-rich fraction of adipocytes was partially characterized, and the results were compared with those of the activity obtained from the plus insulin form of the plasma membrane-rich fraction. The transport activity was determined in a cell-free, reconstituted, system. Prior to reconstitution, the activities in the three preparations were all (a) stable at 0°C for at least 4 h, but not at 37°C or above; (b) most stable at pH 7–9, and (c) less stable in Tes than in Tris buffer. After reconstitution, the three activities were all (d) stable at 0°C, (e) most active at pH 5.5, (f) mildly stimulated by divalent cations, (g) unaffected by insulin or 1 mM of several SH-blocking agents, (h) inhibited by heavy metal ions, 10–100 mM of monovalent salts, organic solvents, several sugar isomers, and specific sugar-transport inhibitors. The rates of d-glucose uptake by the three liposome preparations were all inhibited more strongly by 2-deoxy-d-glucose or $\text{3}\text{-O-}\text{methyl-}\text{d}\text{-glucose}$ than by d-glucose. These data indicate that the general properties of the glucose transport activity in the Golgi-rich fraction are similar to those of the activity in the plasma membrane-rich fraction.     

Combining various strategies to increase the coverage of the plant cell wall glycoproteome

Glycoproteomics recently became a very active field, mostly in mammals. The first part of this paper consists of a mini-review on the strategies used in glycoproteomics, namely methods for enrichment in glycoproteins and mass spectrometry (MS) techniques currently used. In a second part, these strategies are applied to the cell wall glycoproteome of etiolated hypocotyls of Arabidopsis thaliana, showing their complementarity. Several sub-glycoproteomes were obtained by: (i) affinity chromatography on concanavaline A (ConA) and analysis of glycoproteins by MALDI-TOF MS; (ii) multidimensional lectin chromatography (using AIL, PNA, ConA and WGA lectins) and subsequent identification of glycoproteins by MALDI-TOF MS and LC-MS/MS; (iii) boronic acid chromatography followed by identification of glycoproteins by MALDI-TOF MS. Altogether, 127 glycoproteins were identified. Most glycoproteins were found to be putative N-glycoproteins and N-glycopeptides were predicted from MS data using the ProTerNyc bioinformatics software.     

Millimeter waves thermally alter the firing rate of the Lymnaea pacemaker neuron

The effects of millimeter waves (mm-waves, 75 GHz) and temperature elevation on the firing rate of the BP-4 pacemaker neuron of the pond snail Lymnaea stagnalis were studied by using microelectrode techniques. The open end of a rectangular waveguide covered with a thin Teflon film served as a radiator. Specific absorption rates (SARs), measured in physiological solution at the radiator outlet, ranged from 600 to 4200 W/kg, causing temperature rises from 0.3 to 2.2 °C, respectively. Irradiation at an SAR of 4200 W/kg caused a biphasic change in the firing rate, i.e., a transient decrease in the firing rate (69 ± 22% below control) followed by a gradual increase to a new level that was 68 ± 21% above control. The biphasic changes in the firing rate were reproduced by heating under the condition that the magnitude (2 °C) and the rate of temperature rise (0.96 °C/s) were equal to those produced by the irradiation (for an SAR of 4030 W/kg). The addition of 0.05 mM of ouabain caused the disappearance of transient responses of the neuron to the irradiation. It was shown that the rate of temperature rise played an important role in the development of a transient neuronal response. The threshold stimulus for a transient response of the BP-4 neuron found in warming experiments was a temperature rise of 0.0025 °C/s. Bioelectromagnetics 18:89–98, 1997. © 1997 Wiley-Liss, Inc.     

Some aspects of the biology of the red bass, Lutjanus bohar (Forsskal), from the Tigak Islands, Papua New Guinea

The growth rate, food, reproduction and mortality rates of the red bass, Lutjanus bohar , are described for fish associated with coral reefs in the Tigak Islands of Papua New Guinea. Spawning intensity by month was investigated by examination of gonad maturation stages. The length–at–maturity of female L. bohar was estimated from the relationship between changes in gonad index with increasing size. Female fish matured at about 45–0 cm fork length. The Petersen method was used to obtain age–at–length data from length frequency data of L. bohar captured by hook–and–line fishing. The growth of L. bohar was described by a von Bertalanffy growth curve with the parameters AT=0.27 and L_∞ = 81.7 cm. There was a positive correlation between water depth (D) and the length of L. bohar (L) that was described by L = 318–8+ 3.050 D . The mortality rates ( Z ) of L. bohar from shallow (≤30m) and deep (≤80m) water were estimated from length converted catch curves and were 1–181 and 0–64 respectively. The high Z value for the shallow water population of L. bohar was ascribed to the migration of larger specimens into deeper water. The deep water population of L. bohar remains unfished and the estimate of Z was believed to be equivalent to the natural mortality rate ( M ). An empirical method of calculating M gave an estimate of 0.59. Lutjanus bohar is a carnivorous piscivore that feeds throughout the water column.