共查询到20条相似文献,搜索用时 15 毫秒
1.
One subclass of B12-requiring enzymes is now known to bind their B12 coenzymes “base-off,” with a histidine residue from the protein supplying an imidazole ligand to the cobalt center. Recent results from Sirovatka and Finke (J.M. Sirovatka and R.G. Finke, J.Am. Chem. Soc. 119, (1997) 3057) show that imidazole has an extraordinary trans effect on the mode of carbon–cobalt bond cleavage in coenzyme B12 analogs, compared to pyridine or the natural 5,6-dimethylbenzimidazole ligand, and it was suggested that a differential steric effect could, in part, account for the uniqueness of the imidazole ligand. Such a differential steric effect for imidazole and pyridine is now demonstrated by studies of the thermodynamics of ligation of these ligands to the α and β diastereomers of two alkylcobinamides (RCbi+s, derivatives of cobalamins which lack the normal axial nucleotide) based on the known differences in steric crowding of the α (“lower”) and β (“upper”) axial ligand positions of cobalt corrinoids. Imidazole binds more tightly than pyridine to both diastereomers of NCCH2Cbi+ and CF3Cbi+, in all cases due to a more favorable entropy change, which is the result of lowered steric interference with corrin side chain thermal motions. 相似文献
2.
Paul G. Swetik Dennis G. Brown 《Biochimica et Biophysica Acta (BBA)/General Subjects》1974,343(3):641-647
The cobalt(II)—cobalt(I) interconversion in a number of vitamin B1 2 derivatives was investigated by cyclic voltammetry. Particular attention was focused on the factors determining whether the interconversion is reversible. When the lower axial coordination position is occupied by a strong ligand, such as the benzimidazole nucleotide in “base on” cobalamins, the cobalt(II)—cobalt(I) interconversion is irreversible due to a slow reduction of the cobalt(II). However, when the lower axial coordination position is free of a strong ligand, as in most cobinamides or in “base off” cobalamins, the cobalt(II)—cobalt(I) interconversion is nearly perfectly reversible. Possible implications of the observations to B1 2-dependent enzymes are briefly discussed. 相似文献
3.
The effect of axial ligand nodal plane orientation on the contact and pseudocontact shifts of a symmetrical low-spin octamethylferriheme
center has been calculated as a function of the angle of the axial ligand. Simple Hückel techniques have been used to estimate
the contact contribution, and values obtained from model hemes, together with counter-rotation of the g-tensor, have been used to estimate the pseudocontact contribution, for the eight β-pyrrole methyl and four meso-H positions. It is found that the maximum and minimum contact shifts occur when the axial ligand is aligned at an angle of
±15° to the meso-H axes of the heme, rather than when the axial ligand plane lies along the porphyrin nitrogens, as assumed previously by
some investigators. For systems having one planar axial ligand or two ligands in parallel planes, the contact and pseudocontact
contributions at the meso-H positions are comparable in size (at least on the basis of simple Hückel estimates), while the contact contribution clearly
dominates the isotropic shifts of the heme methyls. Allowing for the substituent effect of the 2,4-vinyls of protohemin, or
the 2,4-thioethers of hemin c, as well as the average diamagnetic shifts of the heme methyls and meso-H, plots of the predicted shifts as a function of axial ligand nodal plane orientation have been constructed for hemin b- and c-containing proteins. Excellent agreement in the order of shifts, and reasonable agreement in the sizes of the observed shifts,
is observed in the majority of the ferriheme proteins for which the methyl and meso-H resonances have been assigned and proton shifts reported. Plots have also been constructed for hemin c-containing proteins having the two axial ligand nodal planes oriented at relative angles of 40°, 70°, and 80°. Excellent
agreement in the order of shifts, and reasonable agreement in the magnitudes of the observed shifts, is observed in all cases
of bacterial cytochromes which do not fit the plots that assume the ligands are in parallel planes, except one – the cytochrome
c-552 of Nitrosomonas europae. Except for this case, where the order of the predicted methyl shifts at any angle of the axial ligands disagrees with the
observed, the reasons can usually be attributed to a large dihedral angle between two axial ligand nodal planes, to strong
H-bonding interactions involving His and/or CN– ligands, or to off-axis binding of one (or both) axial ligand(s). Ruffling of the porphyrin ring may also contribute to the
contact shift in as yet undefined ways. Hence, despite the simplicity of the calculations, the agreement with observed data
is highly satisfying and the concept of the importance of axial ligand plane orientation on the observed proton shifts of
heme proteins is fully confirmed.
Received: 15 June 1998 / Accepted: 6 August 1998 相似文献
4.
New Insights on the Burstein-Moss Shift and Band Gap Narrowing in Indium-Doped Zinc Oxide Thin Films
The Burstein-Moss shift and band gap narrowing of sputtered indium-doped zinc oxide (IZO) thin films are investigated as a function of carrier concentrations. The optical band gap shifts below the carrier concentration of 5.61 × 1019 cm-3 are well-described by the Burstein-Moss model. For carrier concentrations higher than 8.71 × 1019 cm-3 the shift decreases, indicating that band gap narrowing mechanisms are increasingly significant and are competing with the Burstein-Moss effect. The incorporation of In causes the resistivity to decrease three orders of magnitude. As the mean-free path of carriers is less than the crystallite size, the resistivity is probably affected by ionized impurities as well as defect scattering mechanisms, but not grain boundary scattering. The c lattice constant as well as film stress is observed to increase in stages with increasing carrier concentration. The asymmetric XPS Zn 2p3/2 peak in the film with the highest carrier concentration of 7.02 × 1020 cm-3 suggests the presence of stacking defects in the ZnO lattice. The Raman peak at 274 cm-1 is attributed to lattice defects introduced by In dopants. 相似文献
5.
The circular and linear dichroism (CD and LD) spectral properties of the meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP)–DNA complex at a [porphyrin]/[DNA] ratio below 0.015 showed that TMPyP intercalates between DNA base pairs. Contrarily, when cis–bis(N-methylpyridinium-4-yl)porphyrin (BMPyP) is associated with DNA, no CD spectrum was induced and a bisignate LD spectrum was observed. These spectral properties of both the TMPyP and BMPyP were essentially retained when the minor groove of the DNA was saturated with 4′,6-diamidino-2-phenylindole (DAPI). The fluorescence of the DNA-bound DAPI was effectively quenched by BMPyP and TMPyP. The quenching by BMPyP can be described through a pure static mechanism while TMPyP quenching produced an upward bending curve in the Stern–Volmer plot. Quenching efficiency was by far greater than predicted by the “sphere of action model”, suggesting that the DNA provides some additional processes for an effective energy transfer. 相似文献
6.
Vincent C. Manganiello Jan Breslow 《Biochimica et Biophysica Acta (BBA)/General Subjects》1974,362(3):509-520
In confluent cultures of “young” (< 30 generations) human fibroblasts, maximally effective concentrations of prostaglandin E1 (5.6 μM) and isoproterenol (2 μM) increased cyclic AMP content several hundred-fold and approximately 30-fold, respectively. On the first day after initiation of cultures at either low (approx. 3 · 105 cells) or high (approx. s · 106 cells) cell density the magnitude of the isoproterenol effect was similar to that in confluent cultures. It increased during the next few days, reaching a maximum around day 2–3, and then declined. On any day during the period of subculture, the magnitude of the isoproterenol effect was inversely related to cell density. Alterations in response to prostaglandin E1 as a function of time in subculture or cell density were less dramatic. The effects of prostaglandin E1 were, however, smaller at some point during the first few days of subculture than after day 7, and when effects of prostaglandin E1 were minimal, those of isoproterenol were maximal and approached those of prostaglandin E1. On any day of subculture, cells in cultures of higher density tended to accumulate more cyclic AMP in response to prostaglandin E1 than did those in low density cultures. The effects of prostaglandin E1 and isoproterenol on cyclic AMP content were qualitatively similar in “young” and in “old” (> 60 generations in culture) human fibroblasts although the changes associated with duration of subculture and cell density tended to be less marked with “old” cells. In the “young” fibroblasts responsiveness to isoproterenol and prostaglandin E1 appears to correlate with cell morphology and with the fractional rate of growth in subcultures. It is suggested that the capacities of the fibroblasts to respond to these two agents may be altered independently during growth of human fibroblasts. 相似文献
7.
N.A. Pchelintsev M.I. Youshko V.K. vedas 《Journal of Molecular Catalysis .B, Enzymatic》2009,56(4):202-207
The microstructure and the catalytic properties of cross-linked enzyme aggregates (CLEA) of penicillin acylase (PA) obtained under different conditions were investigated. The period of time left between the enzyme precipitation and the cross-linking step was found to influence the structural organization of the resulting enzyme preparation. Confocal fluorescent microscopy of the so-called “fresh” and “mature” CLEAs PA allowed to estimate the “characteristic” diameter of CLEA PA particles, which appeared to be about 1.6 μm, and revealed that the “mature” type was composed of relatively big particles as compared to the “fresh” type. Complementary kinetic studies showed that the “mature” CLEA PA were more effective in both hydrolytic and synthetic reactions. It was suggested that the aggregate size might regulate the extent of covalent modification of PA and thereby influence the catalytic properties of CLEA. 相似文献
8.
The iron-free cytochrome c peroxidase (CCP) crystal structure has been determined to 1.13 Å and compared with the 1.2-Å ferric-CCP structure. Quite unexpectedly, removal of the iron has no effect on porphyrin geometry and distortion, indicating that protein–porphyrin interactions and not iron coordination or formation of the axial His–Fe bond determines porphyrin conformation. However, there are changes in solvent structure in the distal pocket, which lead to changes in the distal His52 acid–base catalyst. The observed ability of His52 to move in response to small changes in solvent structure is very likely important for its role as a catalyst in assisting in the heterolytic fission of the peroxide O–O bond. 相似文献
9.
Singer D Mühlfeld C 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2007,148(4):780-784
Mammalian birth is accompanied by profound changes in metabolic rate that can be described in terms of body size relationship (Kleiber's rule). Whereas the fetus, probably as an adaptation to the low intrauterine pO2, exhibits an “inappropriately” low, adult-like specific metabolic rate, the term neonate undergoes a rapid metabolic increase up to the level to be expected from body size. A similar, albeit slowed, “switching-on” of metabolic size allometry is found in human preterm neonates whereas animals that are normally born in a very immature state are able to retard or even suppress the postnatal metabolic increase in favor of weight gain and O2 supply. Moreover, small immature mammalian neonates exhibit a temporary oxyconforming behavior which enhances their hypoxia tolerance, yet is lost to the extent by which the size-adjusted metabolic rate is “locked” by increasing mitochondrial density. Beyond the perinatal period, there are no other deviations from metabolic size allometry among mammals except in hibernation where the temporary “switching-off” of Kleiber's rule is accompanied by a deep reduction in tissue pO2. This gives support to the hypothesis that the postnatal metabolic increase represents an “escape from oxygen” similar to the evolutionary roots of mitochondrial respiration, and that the overall increase in specific metabolic rate with decreasing size might contribute to prevent tissues from O2 toxicity. 相似文献
10.
Optical Properties and Light Climate in Lake Verevi 总被引:2,自引:2,他引:0
The optical properties and light climate during the ice-free period in the highly stratified Lake Verevi (Estonia) have been studied together with other lakes in same region since 1994. The upper water layer above the thermocline belongs to class “moderate” by optical classification of Estonian lakes but can turn “turbid” (concentration of chlorophyll a up to 73 mg m−3 and total suspended matter up to 13.2 g m−3) during late summer blooms. In the blue part of the spectrum, light is mainly attenuated by dissolved organic matter and in red part notably scattering but also absorption by phytoplanktonic pigments effect the spectral distribution of underwater light. Consequently, the underwater light is of greenish-yellow color (550–650 nm). Rapid change in optical properties occurs with an increase of all optically active substances close to thermocline (2.5–6 m). Optical measurements are often hampered beneath this layer so that modeling of the depth distribution of the diffuse attenuation coefficient is an useful compliment to field measurements. Kd,PAR ranges from 0.8 to 2.9 m−1 in the surface layer, and model results suggest that it may be up to 5.8 m−1 in the optically dense layer. This forms a barrier for light penetration into the hypolimnion. 相似文献
11.
Jeff J. Clare 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2006,1(3):309-318
Voltage-gated sodium (NaV) channel inhibitors are an important class of drugs that are used to treat a number of CNS indications including pain, local anaesthesia, epilepsy and bipolar disorder. These drugs all have their origins in traditional “empirical” pharmacology, and it was only some time after discovery that they were found to inhibit NaV channels. The basis for therapeutic selectivity of these drugs within different disease indications is currently unknown. However, the subsequent discovery of a multi-gene family of NaV channels suggests a possible mechanism and has opened the way for more targeted approaches to finding improved therapeutic inhibitors. This article describes some ongoing approaches to systematically clone, express and characterise the entire family of NaV subtypes in order to better understand their properties and define their individual physiological and pathophysiological roles. As well as providing specific disease validation for individual subtypes, this also provides a panel of reagents for comprehensively exploring the efficacy, selectivity and potency relationships of existing NaV-blocking drugs. In this way, a gene family-based approach to NaV channels has enabled a “drug-to-target” approach, reversing the more usual “gene-to-target-to-drug” paradigm. Together with recent advances in assay technology, gene family-based approaches are increasing the tractability of these targets and are re-invigorating NaV drug discovery within the pharmaceutical industry. 相似文献
12.
To measure oxygen saturation (SO2) of flowing erythrocytes in blood vessels of living animals, our “in vivo cryotechnique” (IVCT) was combined with confocal Raman microscopy at low temperature (−150 °C), referred to as cryomicroscopy. We evaluated two resonance Raman (RR) shifts around 1355 and 1378 cm−1, reflecting de-oxygenated and oxygenated hemoglobin molecular structures, respectively. Judging from the calibration analyses of quickly frozen human whole blood for the control experiment in vitro, the two RR shifts were well retained at the low temperature, and their calculated ratios mostly reflected the relative SO2 measured with a blood-gas analyzer. In blood vessels of living mouse organs prepared with the IVCT, their RR spectral peaks were also detected at the same RR shifts obtained in human blood. In the blood vessels of living mouse small intestines, some arterioles and venules were clearly distinguishable by monitoring different peak patterns of their RR shifts. The different ratios of the RR shift-areas were calculated even in the arterial vessels. In blood vessels of mouse livers, the Raman spectra showed a lower peak shift of 1378 cm−1 compared to that of 1355 cm−1, indicating an SO2 decrease in hepatic blood circulation. Thus, the new cryopreparation technique will enable us to directly analyze the in vivo SO2 in various tissues of a whole animal body prepared with the IVCT, reflecting their living states. 相似文献
13.
Photosynthetic responses to irradiance and temperature of “leaves” and receptacles were compared in February (vegetative stage) and May (reproductive stage) in the seaweed, Hizikia fusiforme (Harvey) Okamura (Sargassaceae, Phaeophyta) from Nanao Island, Shantou, China. Irradiance-saturated photosynthesis (Pmax) was significantly higher in receptacles than in “leaves” on a fresh weight basis, and that of “leaves” was greater in May than in February at ambient seawater temperatures. The optimum temperature for Pmax was 30∘C for both “leaves” and receptacles, being 5–10∘C higher than the ambient seawater temperature. The apparent photosynthetic efficiencies were greater in receptacles than in “leaves” within the tested temperature range of 10–40∘C. The irradiance for saturating photosynthesis for both “leaves” and receptacles was temperature-dependent, with the highest values (about 200μmolphotonsm−2s−1) at 30∘C. 相似文献
14.
W. J. Ewens 《Theoretical population biology》1982,21(3):373-378
The concept of the effective population size is discussed. It is shown that the “eigenvalue” and the “inbreeding” effective population sizes are in principle different, even though they have been sometimes identified in the literature. On the other hand the “eigenvalue” and “variance” effective sizes are usually both close when the latter exists. Since, however, there are many models for which a variance effective size cannot in principle exist, it seems useful to introduce the eigenvalue effective size and to examine some of its properties. 相似文献
15.
Gerd N. La Mar Thomas J. Bold James D. Satterlee 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,498(1):189-207
The proton NMR spectra of the bis-4-substituted pyridinates of ferric tetrapheylporphyrin and octaethylporphyrin complexes have been recorded and analyzed fort he purpose of ascertaining the influence of variable axial lignad basicity on the bonding and magnetic properties of the iron. Under the conditions of slow ligand exhange where the bis stoichiometry can be established, all complexes exist exlusively in the low-spin, , state. The hyperfine shifts at ?60° C for both the porphyrins and axial ligands are shown to be very sensitive to the basicity of the substituted pyridine, as measured by its pKa. For the tetraphenylporphyrin complexes, we illustrate that the pattern of the meso-phenyl hyperfine shifts permits a quantitative separation of the contact and dipolar contributions to these shifts. This separation reveals that the shift variations with pyridine pKa are dominated by changes in the magnetic susceptibility anisotropy (dipolar shift), which decreases markedly upon lowering the pyridine basicity; ESR data support this conclusion in the few samples investigated. However, this trend in magnetic anisotropy with ligand basicity is not valid when comparing pyridines with other ligands such as imidazoles. The important change in the contact shift reflects a decrease in porphyrin → iron π change transfer as the ligand basicity is lowered. A correlation between increase in proton NMR linewidth and magnetic anisotrophy of the iron suggests that electron spin relaxation occurs via a process which couples the same levels that control the magnetic anisotropy. 相似文献
16.
The effect of temperature on the conformation of a histone (H3.1) is studied by a coarse-grained Monte Carlo simulation based on three knowledge-based contact potentials (MJ, BT, BFKV). Despite unique energy and mobility profiles of its residues, the histone H3.1 undergoes a systematic (possibly continuous) structural transition from a random coil to a globular conformation on reducing the temperature. The range over which such a systematic response in variation of the radius of gyration (Rg) with the temperature (T) occurs, however, depends on the potential, i.e. ΔTMJ ≈ 0.013–0.020, ΔTBT ≈ 0.018–0.026, and ΔTBFKV ≈ 0.006–0.013 (in reduced unit). Unlike MJ and BT potentials, results from the BFKV potential show an anomaly where the magnitude of Rg decreases on raising the temperature in a range ΔTA ≈ 0.015–0.018 before reaching its steady-state random coil configuration. Scaling of the structure factor, S(q) ∝ q−1/ν, with the wave vector, q = 2π/λ, and the wavelength, λ, reveals a systematic change in the effective dimension (De∼1/ν) of the histone with all potentials (MJ, BT, BFKV): De∼3 in the globular structure with De∼2 for the random coil. Reproducibility of the general yet unique (monotonic) structural transition of the protein H3.1 with the temperature (in contrast to non-monotonic structural response of a similar but different protein H2AX) with three interaction sets shows that the knowledge-based contact potential is viable tool to investigate structural response of proteins. Caution should be exercise with the quantitative comparisons due to differences in transition regimes with these interactions. 相似文献
17.
Changes in hydrogen peroxide homeostasis and cytokinin levels contribute to the regulation of shade-induced senescence in wheat leaves 总被引:1,自引:0,他引:1
Humberto F. Causin Irma N. Roberts María V. Criado Susana M. Gallego Liliana B. Pena María del Carmen Ríos Atilio J. Barneix 《Plant science》2009,177(6):698-704
In a previous work we demonstrated that the suppression of blue light in shaded leaves of wheat increases their senescence rate and the development of oxidative stress symptoms. In order to better understand the interaction between the oxidative metabolism and light spectral quality in the regulation of leaf senescence, we studied the evolution of H2O2 concentration, protein oxidation, proteolytic activity and cytokinin content in excised leaves, either illuminated (control, “C”) or shaded under blue (“B”, high blue light transmission) or green (“G”, very low blue light transmission) light filters. H2O2 concentration significantly increased during the first 9 h after treatment initiation, an effect that was consistently higher in treatments B and C. Leaves from these treatments showed lower chlorophyll and protein degradation rates, lower concentration of oxidized proteins, and maintained higher levels of the cytokinin isopentenyl-adenosine than those from treatment G. When moderate H2O2 concentrations were supplied during 6–9 h after the onset of the shade treatments, senescence rate in treatment G was delayed, while the opposite effect was observed in the presence of the H2O2 scavengers catalase and, to a lesser extent, dimethylthiourea. These effects were accompanied by an increment or a decrement, respectively, of catalase activity, suggesting that the early changes in H2O2 homeostasis in leaves from treatments B and C may contribute to the prevention rather than to the induction of further oxidative damage. Altogether our results show that the suppression of blue light transmission in shaded leaves act as a stress signal that increases their sensitivity to oxidative stress and accelerates cell death. 相似文献
18.
Patricia C. Carrera Camilo I. Mattoni Alfredo V. Peretti 《Zoology (Jena, Germany)》2009,112(5):332-350
Specialised structures that enable males to grasp females during sexual interactions are highly susceptible to selection and thus diverge relatively rapidly over evolutionary time. These structures are often used to test hypotheses regarding sexual selection such as sexually antagonistic co-evolution and sexual selection by female choice. In the present study, we determine whether there is a relationship between a novel record of scorpion sexual dimorphism, the sexual dimorphism of chelicerae (CSD), and the presence of the mating behaviour termed “cheliceral grip” (CG). The presence of both traits in the order Scorpiones is also reviewed from a phylogenetic perspective. The results confirm a strong relationship between CSD and the presence of CG. The morphological and behavioural patterns associated with “CSD–CG” are opposed to the predictions postulated by the hypothesis of sexually antagonistic co-evolution. However, if the female shows resistance after the deposition of the spermatophore, the possibility that the male exerts pressure as a “cryptic form” of coercion to prevent the interruption of mating cannot be ruled out completely. Female choice by “mechanical fit” could be another explanation for some aspects of the CG's contact zone. The possibility that the “CG–CSD” complex has evolved under natural selection in order to ensure sperm transfer is also considered. 相似文献
19.
The porphyrin, meso-5-(pentafluorophenyl)-10, 15, 20-tris(4-pyridyl)porphyrin has been used to synthesize two new metalloporphyrin complexes. Insertion of copper(II) into the porphyrin center gives the copper(II) porphyrin. Coordination of three [Ru(bipy)2Cl]+ moieties (where bipy = 2,2′-bipyridine) to the pyridyl nitrogens of the copper(II) porphyrin gives the target complex. Electronic transitions associated with the copper(II) porphyrin and the triruthenium copper(II) porphyrin include an intense Soret band and a less intense Q-band in the visible region of the spectrum. An intense π-π∗ transition in the UV region associated with the bipyridyl groups and a metal to ligand charge transfer (MLCT) band appearing as a shoulder to the Soret band are observed for the ruthenated copper(II) porphyrin. Electrochemical properties associated with the multimetallic complex include a redox couple in the cathodic region with E1/2 = −0.86 V versus Ag/AgCl attributed to the porphyrin and a redox couple in the anodic region E1/2 = 0.88 V versus Ag/AgCl due to the RuIII/II couple. DNA titrations indicate the triruthenium copper(II) porphyrin interacts with DNA potentially through a groove binding mechanism. Irradiation of aqueous solutions of the target complex and supercoiled DNA at a 10:1 base pair to complex ratio with visible light above 400 nm indicates that the complex causes nicking of the DNA helix. 相似文献
20.
Hong Kong’s worst “red tide”—causative factors reflected in a phytoplankton study at Port Shelter station in 1998 总被引:1,自引:0,他引:1
From March through April 1998, a massive “red tide” occurred in coastal waters of south China, including Hong Kong. The “red tide” rapidly killed various species of caged fish and affected coral fishes, killing a few of them, and caused great economic loss and ecological damage. Samples collected from a permanent station located in Port Shelter revealed a new dinoflagellate species, Karenia digitata which was suspected to be the causative species of this “red tide”. Species composition and abundance analysis revealed that an algal bloom persisted in Port Shelter during this entire period. Diatoms and dinoflagellates were the two main groups which dominated the phytoplankton and, in general, when there was an increase in the density of diatoms there was a decline in the density of dinoflagellates, and vice versa. The suspected “red tide” causative species together with other dinoflagellate species started to bloom in late February and reached their highest density on 18 March, when fish kills were first reported at Crooked Island, a semi-enclosed bay to the northeast of Hong Kong. During a 16-week period, dinoflagellate species dominated three times, and coincided with low wind speeds. Constant salinity and a continuing increase in sea surface water temperature suggested warm water intrusion into Hong Kong’s coastal waters during this “red tide” bloom period. Various nutrient elements, e.g. NH4-N, total Kjeldahl nitrogen (TKN), and PO4-P were high at the beginning of the bloom but experienced a sharp decrease thereafter. It is suggested that this early 1998 massive “red tide” in Hong Kong waters might have been triggered by a synchronous appearance of optimal climatic, nutritional and hydrographic conditions. 相似文献