WLIP and tolaasin I, lipodepsipeptides from Pseudomonas reactans and Pseudomonas tolaasii, permeabilise model membranes

The activity of the White Line Inducing Principle (WLIP) and tolaasin I, produced by virulent strains of Pseudomonas reactans and Pseudomonas tolaasii, respectively, was comparatively evaluated on lipid membranes. Both lipodepsipeptides were able to induce the release of calcein from large unilamellar vesicles. Their activity was dependent on the toxin concentration and liposome composition and in particular it increased with the sphingomyelin content of the membrane. Studies of dynamic light scattering suggested a detergent-like activity for WLIP at high concentration (> 27 microM). This effect was not detected for tolaasin I at the concentrations tested (< 28 microM). Differences were also observed in lipodepsipeptides secondary structure. In particular, the conformation of the smaller WLIP changed slightly when it passed from the buffer solution to the lipid environment. On the contrary, we observed a valuable increment in the helical content of tolaasin I which was inserted in the membrane core and oriented parallel to the lipid acyl chains.     

Biological characterization of white line-inducing principle (WLIP) produced by Pseudomonas reactans NCPPB1311

The biological activities of the lipodepsipeptides (LDP) white line-inducing principle (WLIP), produced by Pseudomonas reactans NCPPB1311, and tolaasin I, produced by R tolaasii NCPPB2192, were compared. Antimicrobial assays showed that both LDP inhibited the growth of fungi-including the cultivated mushrooms Agaricus bisporus, Lentinus edodes, and Pleurotus spp.--chromista, and gram-positive bacteria. Assays of the two LDP on blocks of Agaricus bisporus showed their capacity to alter the mushrooms' pseudo-tissues though WLIP was less active than that of tolaasin I. Contrary to previous studies, tolaasin I was found to inhibit the growth of gram-negative bacteria belonging to the genera Escherichia, Erwinia, Agrobacterium, Pseudomonas, and Xanthomonas. The only gram-negative bacterium affected by WLIP was Erwinia carotovora subsp. carotovora. Both WLIP and tolaasin I caused red blood cell lysis through a colloid-osmotic shock mediated by transmembrane pores; however, the haemolytic activity of WLIP was greater than that of tolaasin I. Transmembrane pores, at a concentration corresponding to 1.5 x C50, showed a radius between 1.5 and 1.7 +/- 0.1 nm for WLIP and 2.1 +/- 0.1 nm for tolaasin I. The antifungal activity of WLIP together with the finding that avirulent morphological variants of P. reactans lack WLIP production suggests that WLIP may play an important role in the interaction of the producing bacterium P. reactans and cultivated mushrooms.     

Characterization of zinc-binding properties of a novel imidase from Pseudomonas putida YZ-26

The imidase from Pseudomonas putida YZ-26 consisting of 293-amino acid residues is a novel imidase with four subunits as the holo-enzyme and low molecular weight which is significantly different from known mammalian imidase. This study measured the zinc-binding properties of the imidase using inductively coupled plasma-atomic emission spectrometry and competition assay combined with activity determinations. Results show that each subunit of the imidase binds the zinc ion by 1:1 stoichiometry with apparent binding constant of 9.5 × 10⁸ M⁻¹. The activity of the apo-imidase (20 μM) was recovered with the addition of zinc in the lower concentration (0-20 μM), whereas the enzymatic activity is decreased in the presence of high concentration of zinc (above 100 μM). The site-directed mutagenesis of His₂₄₇, His₈₆ or Cys₇, Cys₁₀₈ in imidase resulted in loss of activity and zinc-binding abilities at different degrees, showing that these residues may critically affect both enzymatic activity and conformation.     

Biochemical characterization and evaluation of potent inhibitors of the Pseudomonas aeruginosa PA01 acetohydroxyacid synthase

Microbes and plants synthesize essential branched-chain amino acids (BCAAs) such as valine, leucine, and isoleucine via a common biosynthetic pathway in which the first reaction is catalyzed by acetohydroxyacid synthase (AHAS, EC 4.1.3.18). Recently, AHAS was identified as a potential anti bacterial target. To help find an effective inhibitor that could act as an antibacterial compound, we cloned and characterized the catalytic subunit (CSU) of Pseudomonas aeruginosa AHAS, and found four potent inhibitors through chemical library screening. The ilvI gene of P. aeruginosa encodes a 65-kDa AHAS protein, consistent with the size of the purified enzyme on SDS-PAGE. Enzyme kinetics showed that the enzyme has a K_m of 14.2 mM and a specific activity of 0.12 U/mg. Enzyme activity was optimum at a temperature of 37 °C and a pH of 7.5. The K_d for thiamine diphosphate (ThDP) was 89.92 ± 17.9 μM, as determined by fluorescence quenching. The cofactor activation constants (K_s) for ThDP and (K_c) for Mg²⁺ were 0.6 ± 0.1 and 560.8 ± 7.4 μM, respectively. Further, we determined that AVS2087, AVS2093, AVS2236, and AVS2387 compounds are potent inhibitors of the catalytic subunit of P. aeruginosa AHAS. These compounds inhibit nearly 100% of AHAS activity, with IC₅₀ values of 1.19 μM, 5.0 nM, 25 nM, and 13 nM, respectively. Compound AVS2093 showed growth inhibition with a minimal inhibitory concentration (MIC) of 742.9 μg/ml against P. aeruginosa strain ATCC 9027. Furthermore, these findings were supported by molecular docking studies with the AVS compounds against P. aeruginosa AHAS in which AVS2093 showed minimum binding energy (−7.8 kJ/mol) by interacting with the receptor through a single hydrogen bond of 2.873 Å. Correlation of AVS2093 activity with P. aeruginosa AHAS cell growth inhibition suggested that AHAS might serve as a target protein for the development of novel antibacterial therapeutics. Results of the current study provide an impetus to further evaluate the potency of these inhibitors against pathogenic P. aeruginosa strains in vivo and to design more potent antibacterial agents based on these AVS inhibitors.     

A predicted S-type pyocin shows a bactericidal activity against clinical Pseudomonas aeruginosa isolates through membrane damage

The nucleic acid sequence at the positions 1067817-1066321 of Pseudomonas aeruginosa PAO1 genome was predicted to encode a novel S-type pyocin, designated S5, based on the genome sequence. However, its antimicrobial spectrum, activity and mechanism have not been investigated. Herein, we report that pyocin S5 has an antimicrobial activity against seven clinical P. aeruginosa isolates (DWW3, InA, InB, In3, In4, In7, and In8). Among them, DWW3 is most sensitive with a minimum inhibitory concentration of 12.6 μg/ml and a killing percentage of 95.7 at 225 μg/ml. Further, we demonstrated that the antimicrobial mechanism of pyocin S5 is membrane damage, evidenced by the leakage of intracellular materials, the increase of membrane permeability, and cell surface disruption.     

Effect of biosurfactant and fertilizer on biodegradation of crude oil by marine isolates of Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa

This study was conducted to investigate the effects of fertilizers and biosurfactants on biodegradation of crude oil by three marine bacterial isolates; Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa. Five sets of experiments were carried out in shake flask and microcosm conditions with crude oil as follows: Set 1-only bacterial cells added (no fertilizer and biosurfactant), Set 2-with additional fertilizer only, Set 3-with additional biosurfactant only, Set 4-with added biosurfactant + fertilizer, Set 5-with no bacterial cells added (control), all the above experimental sets were incubated for 168 h. The biosurfactant + fertilizer added Set 4, resulted in maximum crude oil degradation within shake flask and microcosm conditions. Among the three bacterial isolates, P. aeruginosa and biosurfactant produced by this strain resulted in maximum crude oil degradation compared to the other two bacterial strains investigated. Interestingly, when biosurfactant and bacterial cells were used (Set 3), significant oil biodegradation activity occurred and the difference between this treatment and that in Set 4 with added fertilizer + biosurfactant were only 4-5% higher degradation level in shake flask and 3.2-7% in microcosm experiments for all three bacterial strains used. It is concluded that, biosurfactants alone capable of promoting biodegradation to a large extent without added fertilizers, which will reduce the cost of bioremediation process and minimizes the dilution or wash away problems encountered when water soluble fertilizers used during bioremediation of aquatic environments.     

Catechol 1,2-dioxygenase from the new aromatic compounds - Degrading Pseudomonas putida strain N6

This study aimed to characterization of catechol 1,2-dioxygenase from a Gram-negative bacterium, being able to utilize a wide spectrum of aromatic substrates as a sole carbon and energy source. Strain designated as N6, was isolated from the activated sludge samples of a sewage treatment plant at Bentwood Furniture Factory Jasienica, Poland. Morphology, physio-biochemical characteristics and phylogenetic analysis based on 16S rDNA sequence indicate that strain belongs to Pseudomonas putida. When cells of strain N6 grown on protocatechuate or 4-hydroxybenzoic acid mainly protocatechuate 3,4-dioxygenase was induced. The activity of catechol 1,2-dioxygenase was rather small. The cells grown on benzoic acid, catechol or phenol showed high activity of only catechol 1,2-dioxygenase. This enzyme was optimally active at 35 °C and pH 7.4. Kinetic studies showed that the value of K_m and V_max was 85.19 ??M and 14.54 ??M min⁻¹ respectively. Nucleotide sequence of gene encoding catechol 1,2-dioxygenase in strain N6 has 100% identity with catA genes from two P. putida strains. The deduced 301-residue sequence of enzyme corresponds to a protein of molecular mass 33.1 kDa. The deduced molecular structure of the catechol 1,2-dioxygenase from P. putida N6 was very similar and characteristic for the other intradiol dioxygenases.     

Pseudomonas soli sp. nov., a novel producer of xantholysin congeners

A chemoorganotrophic Gram-negative bacterium was isolated by means of a diffusion sandwich system from a soil sample from the Sierra Nevada National Park, Spain. Strain F-279,208^T was oxidase and catalase positive, strictly aerobic, non-spore-forming and motile by single polar flagellum. Phylogenetic analysis of the 16S rRNA, gyrB, rpoB and rpoD genes revealed that strain F-279,208^T belongs to the Pseudomonas putida group with Pseudomonas mosselii and Pseudomonas entomophila as its closest relatives. DNA–DNA hybridization assays and phenotypic traits confirmed that this strain belongs to a novel species of the genus Pseudomonas, for which the name Pseudomonas soli sp. nov. is proposed. The type strain is F-279,208^T (=DSM 28043^T = LMG 27941^T), and during fermentation it produces xantholysins, a family of lipodepsipeptides. The major compound, xantholysin A, showed an interesting activity in a RCC4 kidney tumor cell line with inactivation of VHL linked with the HIF pathway, without any cytotoxic effects against other human tumor cell lines tested including, liver, pancreas and breast.     

In silico and in vitro comparative activity of novel experimental derivatives against Leishmania major and Leishmania infantum promastigotes

This in silico and in vitro comparative study was designed to evaluate the effectiveness of some biurets (K1 to K8) and glucantime against Leishmania major and Leishmania infantum promastigotes. Overall, eight experimental ligands and glucantime were docked using AutoDock 4.3 program into the active sites of Leishmania major and Leishmania infantum pteridine reductase 1, which were modeled using homology modeling programs. The colorimetric MTT assay was used to find L. major and L. infantum promastigotes viability at different concentrations of biuret derivatives in a concentration and time-dependent manner and the obtained results were expressed as 50% and 90% of inhibitory concentration (IC₅₀ and IC₉₀). In silico method showed that out of eight experimental ligands, four compounds were more active on pteridine reductase 1. K3 was the most active against L. major promastigotes with an IC₅₀ of 6.8 μM and an IC₉₀ of 40.2 μM, whereas for L. infantum promastigotes was K8 with IC₅₀ of 7.8 μM. The phenylethyl derivative (K7) showed less toxicity (IC₅₀s > 60 μM) in both Leishmania strains. Glucantime displayed less growth inhibition in concentration of about 20 μM. In silico and especially docking results in a recent study were in accordance with the in vitro activity of these compounds in presented study and compound K3, K2 and K8 showed reasonable levels of selectivity for the Leishmania pteridine reductase 1.     

Antimicrobial peptides isolated from Phyllomedusa nordestina (Amphibia) alter the permeability of plasma membrane of Leishmania and Trypanosoma cruzi

Nature has provided inspiration for Drug Discovery studies and amphibian secretions have been used as a promising source of effective peptides which could be explored as novel drug prototypes for neglected parasitic diseases as Leishmaniasis and Chagas disease. In this study, we isolated four antimicrobial peptides (AMPs) from Phyllomedusa nordestina secretion, and studied their effectiveness against Leishmania (L.) infantum and Trypanosoma cruzi. The antiparasitic fractions were characterized by mass spectrometry and Edman degradation, leading to the identification of dermaseptins 1 and 4 and phylloseptins 7 and 8. T. cruzi trypomastigotes were susceptible to peptides, showing IC₅₀ values in the range concentration of 0.25–0.68 μM. Leishmania (L.) infantum showed susceptibility to phylloseptin 7, presenting an IC₅₀ value of 10 μM. Except for phylloseptin 7 which moderate showed cytotoxicity (IC₅₀ = 34 μM), the peptides induced no cellular damage to mammalian cells. The lack of mitochondrial oxidative activity of parasites detected by the MTT assay, suggested that peptides were leishmanicidal and trypanocidal. By using the fluorescent probe SYTOX® Green, dermaseptins 1 and 4 and phylloseptins 7 and 8 showed time-dependent plasma membrane permeabilization of T. cruzi; phylloseptin 7 also showed a similar effect in Leishmania parasites. The present study demonstrates for the first time that AMPs target the plasma membrane of Leishmania and T. cruzi, leading to cellular death. Considering the potential of amphibian peptides against protozoan parasites and the reduced mammalian toxicity, they may contribute as scaffolds for drug design studies.     

Biological activity of l-2-azetidinecarboxylic acid,isolated from Polygonatum odoratum var. pluriflorum, against several algae

The biological activities of an aqueous fraction extracted from Polygonatum odoratum var. pluriflorum Owhi and of l-2-azetidinecarboxylic acid (AZC), purified from the extract, on the growth of several types of algae were tested. The aqueous fraction was prepared by methanol extraction of P. odoratum var. pluriflorum rhizomes followed by reverse partitioning with butanol. The aqueous extraction inhibited growth of the green alga Chlorella vulgaris by less than 10% at a concentration of 1000 mg L⁻¹. However, growth of the blue-green alga Microcystis aeruginosa was inhibited by 22.0%, 67.9%, and 87.1%, respectively, at 3.1, 6.2, and 12.5 mg extract L⁻¹. AZC was isolated from the aqueous extract and was shown to be the major active substance inhibiting algal growth. AZC concentrations higher than 25 μM inhibited growth, while at 400 μM, growth of the green algae C. vulgaris and Scenedesmus spp. was inhibited by 71.2% and 70.4%, respectively. In contrast, growth of the blue-green algae Anabaena affinis and M. aeruginosa was inhibited at concentrations greater than 1.6 and 0.2 μM, respectively, whereas 92% control required concentrations of 6.3 and 1.6 μM, respectively. AZC also suppressed the growth of the red-tide microalga Cochlodinium polykrikoides by 86.9% and 100% at concentrations of 6.3 and 12.5 μM, respectively. Azetidine and 2-azetidinone showed little activity on the tested algae. The results demonstrate that AZC selectively inhibits algal growth at low concentrations. The green algae C. vulgaris and Scenedesmus spp. were tolerant, whereas M. aeruginosa, A. affinis, and C. polykrikoides were relatively sensitive. Thus, extract and AZC, prepared from P. odoratum rhizomes, showed a potential as natural selective algicide for the control of harmful algae in laboratory assay.     

Simultaneous Cr(VI) reduction and phenol degradation in pure cultures of Pseudomonas aeruginosa CCTCC AB91095

Simultaneous Cr(VI) reduction and phenol degradation were investigated in a reactor containing Pseudomonas aeruginosa CCTCC AB91095. Phenol was used as carbon source. P.aeruginosa utilized metabolites formed during phenol degradation as energy source for Cr(VI) reduction. Cr(VI) inhibited both Cr(VI) reduction and phenol degradation when Cr(VI) concentration exceeded the optimum value (20 mg/L), whereas phenol enhanced both Cr(VI) reduction and phenol degradation below the optimum initial concentration of 100 mg/L. Cr(III) was the predominant product of Cr(VI) reduction in cultures after incubation for 24 h. Both Cr(VI) reduction and phenol degradation were influenced by the amount of inocula. The concentration of Cr(VI) and phenol declined quickly from 20, 100 to 3.36, 29.51 mg/L in cultures containing of 5% (v/v) inoculum after incubation for 12 h, respectively. The whole study showed that P. aeruginosa is promising for the reduction of toxic Cr(VI) and degradation of organic pollutants simultaneously in the mineral liquid medium.     

High-level expression of glutaryl-7-aminocephalosporanic acid acylase from Pseudomonas diminuta NK703 in Escherichia coli by combined optimization strategies

In this work, a glutaryl-7-aminocephalosporanic acid acylase (GLA) coding gene was cloned from Pseudomonas diminuta NK703 which was screened from oilfield. The concerted effects of the expression system, inducing condition and culture medium on the expression of NK703 GLA in E. coli were firstly investigated. The best combination was the recombinant E. coli strain of pET-28a + GLA/BL21(DE3) with 2.0% (w/v) lactose inducing in YT medium at 25 °C. Then, by optimizing the components of culture medium, a synthetic medium with dextrin and a feeding medium with glycerol as the carbon sources were developed to further enhance the GLA yield and improve the GLA solubility. In the end, the NK703 GLA activity increased about 50-fold, reached 14,470 ± 465 U/L, and the GLA productivity and the proportion of soluble GLA to the total soluble protein attained 206.0 ± 9.033 U L⁻¹ h⁻¹ and 60.13%, respectively. Scaling up the GLA production in 3.7 L fermenter under the optimized conditions identified in shake flask, the GLA activity also reached 12,406 ± 521 U/L, which was the highest report at fermenter level.     

Botryorhodines A-D, antifungal and cytotoxic depsidones from Botryosphaeria rhodina, an endophyte of the medicinal plant Bidens pilosa

An endophytic fungus (Botryosphaeria rhodina) was isolated from the stems of the medicinal plant Bidens pilosa (Asteraceae) that is known for its anti-inflammatory, antiseptic and antifungal effects. The ethyl acetate extract of the fungal isolate exhibits significant antifungal activity as well as potent cytotoxic and antiproliferative effects against several cancer cell lines. Activity-guided fractionation resulted in the isolation of a complex of four depsidones, botryorhodines A-D and the auxin indole carboxylic acid. Botryorhodine A and B show moderate to weak cytotoxic activities against HeLa cell lines with a CC₅₀ of 96.97 μM and 36.41 μM, respectively. In addition, they also show antifungal activity against a range of pathogenic fungi such as Aspergillus terreus (MIC 26.03 μM for botryorhodine A and 49.70 μM for B) and the plant pathogen Fusarium oxysporum (MIC 191.60 μM for botryorhodine A and 238.80 μM for B). A potential role of the endophyte in modulating fungal populations living within or attacking the host plant is discussed.     

Sorgoleone,a sorghum root exudate: Algicidal activity and acute toxicity to the ricefish Oryzias latipes

The discovery of natural and natural-based compounds has resulted in its application as an alternative to synthetic algicides to control harmful algae in aquatic systems. Of the many natural-product-based algicides, sorgoleone, a natural plant product from Sorghum bicolor root exudates has been investigated for its controlling effect on different algal species and its acute fish toxicity. Growth of the blue green algal species Microcystis aeruginosa Kützing was completely inhibited by the crude methanol extract of sorghum root at 20 μg mL⁻¹. The most noticeable inhibition was observed in the bioassay of n-hexane soluble extract, where 98% growth inhibition occurred in M. aeruginosa at the concentration of 1.25 μg mL⁻¹. Sorgoleone very effectively controlled blue green algae inhibiting 97% of M. aeruginosa at 0.5 μg mL⁻¹ and 99% of Anabaena affinis Lemmermann at 4 μg mL⁻¹. In contrast, inhibition of the green algae species Chlorella vulgaris Beijerinck and Scenedensmus spp. at 16 μg mL⁻¹ sorgoleone was 87 and 68%, respectively. There were no mortalities or adverse effects observed in any of the fish exposed to water control, solvent control, and a nominal concentration of 1 μg mL⁻¹ during the test period. The no observed effect concentration (NOEC) value was 1.5 μg mL⁻¹ for the tested fish (O. latipes). Sorgoleone can be considered as an effective and an ecologically and environmentally sustainable approach to controlling harmful algae.     

Respiratory system of Gluconacetobacter diazotrophicus PAL5 Evidence for a cyanide-sensitive cytochrome bb and cyanide-resistant cytochrome ba quinol oxidases

In highly aerobic environments, Gluconacetobacter diazotrophicus uses a respiratory protection mechanism to preserve nitrogenase activity from deleterious oxygen. Here, the respiratory system was examined in order to ascertain the nature of the respiratory components, mainly of the cyanide sensitive and resistant pathways. The membranes of G. diazotrophicus contain Q₁₀, Q₉ and PQQ in a 13:1:6.6 molar ratios. UV_360 nm photoinactivation indicated that ubiquinone is the electron acceptor for the dehydrogenases of the outer and inner faces of the membrane. Strong inhibition by rotenone and capsaicin and resistance to flavone indicated that NADH-quinone oxidoreductase is a NDH-1 type enzyme. KCN-titration revealed the presence of at least two terminal oxidases that were highly sensitive and resistant to the inhibitor. Tetrachorohydroquinol was preferentially oxidized by the KCN-sensitive oxidase. Neither the quinoprotein alcohol dehydrogenase nor its associated cytochromes c were instrumental components of the cyanide resistant pathway. CO-difference spectrum and photodissociation of heme-CO compounds suggested the presence of cytochromes b-CO and a₁-CO adducts. Air-oxidation of cytochrome b (432 nm) was arrested by concentrations of KCN lower than 25 μM while cytochrome a₁ (442 nm) was not affected. A KCN-sensitive (I₅₀ = 5 μM) cytochrome bb and a KCN-resistant (I₅₀ = 450 μM) cytochrome ba quinol oxidases were separated by ion exchange chromatography.     

Conversion of squid pen by Pseudomonas aeruginosa K187 fermentation for the production of N-acetyl chitooligosaccharides and biofertilizers

Pseudomonas aeruginosa K187, a protease- and chitinase-producing bacterium, exhibited protease and chitinase activity after three and five days of incubation, respectively. The protease and chitinase were both produced by using 1% squid pen powder (SPP) (w/v) as sole carbon and nitrogen source. After fermentation, the deproteinization rate of the recovered squid pen gradually increased up to 68% on the fourth day. After five days of fermentation, the production of GlcNAc, (GlcNAc)₂, (GlcNAc)₃, (GlcNAc)₄ and (GlcNAc)₅ were 1.18 mg/mL, 0.76 mg/mL, 1.02 mg/mL, 0.93 mg/mL and 0.90 mg/mL, respectively. The culture supernatant of K187 also exhibited activity of enhancing vegetable growth. For Brassica chinensis Linn treated with the fifth day culture supernatant, the total weight and total length increased up to 529% and 148%, respectively, compared to the control group. With this method, the production of protease, chitinase, N-acetyl chitooligosaccharides and biofertilizers may be useful for biological applications.     

Nematicidal activity of Haplophyllum tuberculatum and Plectranthus cylindraceus oils against Meloidogyne javanica

The potentials of Haplophyllum tuberculatum and Plectranthus cylindraceus oils to control Meloidogyne javanica were investigated in vitro and in a greenhouse. A mixture of Haplophyllum and Plectranthus oils (1:1) was highly toxic to M. javanica in vitro, as it killed all nematode juveniles and inhibited hatching of eggs at 12.5 μg/ml concentration after 24 h exposure time, as did carbofuran at the same concentration. In the green-house, tomatoes grown in soil treated with a combination (1:1) of the two oils developed fewer root galls than those grown in soil treated with higher doses of either oil. The oil mixture, at 2.5 and 5.0 μg/ml of soil, was not phytotoxic to tomato plants as evident from the appearance and height of plants after 12 weeks exposure time, compared to treatment over the same period at lower effective doses. The nematicidal activity of the combined essential oils was suggested by the presence of C₁₀ dienes, C₁₀ trienes and C₁₀ phenol.     

Cadmium accumulation in Atriplex halimus subsp. schweinfurthii and its influence on growth,proline, root hydraulic conductivity and nutrient uptake

Atriplex halimus subsp. schweinfurthii is a newly found cadmium (Cd)-hyperaccumulator, but there have been no detailed studies on its physiological responses when Cd is hyperaccumulated. A. halimus was grown in hydroponic conditions to investigate the effect of cadmium chloride (CdCl₂) on growth, water status, leaf chlorophyll concentration, proline and Cd accumulation. Treatments were prepared by adding 0, 50, 100, 200 and 400 μM CdCl₂ to the nutrient medium. Plant growth was significantly affected at high-Cd treatments. Increased CdCl₂ decreased chlorophyll concentration, transpiration and root hydraulic conductivity (L₀). Hence water flux had only a little effect on the uptake of Cd in A. halimus seedlings. In contrast, proline content increased with increasing CdCl₂ concentration. Plants accumulated substantial amount of Cd in different plant parts (shoot and root). Most of the Cd taken up was retained in roots (606.51 μg g⁻¹DW after 15 d at 400 μM CdCl₂). The addition of Cd in the culture medium affected calcium (Ca) and potassium (K) nutrition in both shoot and root. A. halimus provides a new plant resource for exploring the mechanism of Cd hyperaccumulation and has potential for use in the phytostabilization of Cd-contaminated salt soils.