In Search of Effective UiO-66 Metal-Organic Frameworks for Artificial Kidney Application.

The removal of uremic toxins from patients with acute kidney injury is a key issue in improving the quality of life for people requiring peritoneal dialysis. The currently utilized method for the removal of uremic toxins from the human organism is hemodialysis, performed on semipermeable membranes where the uremic toxins, along with small molecules, are separated from proteins and blood cells. In this study, we describe a mixed-linker modulated synthesis of zirconium-based metal-organic frameworks for efficient removal of uremic toxins. We determined that the efficient adsorption of uremic toxins is achieved by optimizing the ratio between -amino functionalization of the UiO-66 structure with 75% of -NH2 groups within organic linker structure. The maximum adsorption of hippuric acid and 3-indoloacetic acid was achieved by UiO-66-NH2 (75%) and by UiO-66-NH2 (75%) 12.5% HCl prepared by modulated synthesis. Furthermore, UiO-66-NH2 (75%) almost completely adsorbs 3-indoloacetic acid bound to bovine serum albumin, which was used as a model protein to which uremic toxins bind in the human body. The high adsorption capacity was confirmed in recyclability test, which showed almost 80% removal of 3-indoloacetic acid after the third adsorption cycle. Furthermore, in vitro cytotoxicity tests as well as hemolytic activity assay have proven that the UiO-66-based materials can be considered as potentially safe for hemodialytic purposes in living organisms.

Characterization of Endophytic Fungi, Acremonium sp., from Lilium davidii and Analysis of Its Antifungal and Plant Growth-Promoting Effects.

The present study was aimed at isolating endophytic fungi from the Asian culinary and medicinal plant Lilium davidii and analyzing its antifungal and plant growth-promoting effects. In this study, the fungal endophyte Acremonium sp. Ld-03 was isolated from the bulbs of L. davidii and identified through morphological and molecular analysis. The molecular and morphological analysis confirmed the endophytic fungal strain as Acremonium sp. Ld-03. Antifungal effects of Ld-03 were observed against Fusarium oxysporum, Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi. The highest growth inhibition, i.e., 78.39 ± 4.21%, was observed for B. dothidea followed by 56.68 ± 4.38%, 43.62 ± 3.81%, and 20.12 ± 2.45% for B. cinerea, F. fujikuroi, and F. oxysporum, respectively. Analysis of the ethyl acetate fraction through UHPLC-LTQ-IT-MS/MS revealed putative secondary metabolites which included xanthurenic acid, valyl aspartic acid, gancidin W, peptides, and cyclic dipeptides such as valylarginine, cyclo-[L-(4-hydroxy-Pro)-L-leu], cyclo(Pro-Phe), and (3S,6S)-3-benzyl-6-(4-hydroxybenzyl)piperazine-2,5-dione. Other metabolites included (S)-3-(4-hydroxyphenyl)-2-((S)-pyrrolidine-2-carboxamido)propanoic acid, dibutyl phthalate (DBP), 9-octadecenamide, D-erythro-C18-Sphingosine, N-palmitoyl sphinganine, and hydroxypalmitoyl sphinganine. The strain Ld-03 showed indole acetic acid (IAA) production with or without the application of exogenous tryptophan. The IAA ranged from 53.12 ± 3.20 µg ml-1 to 167.71 ± 7.12 µg ml-1 under different tryptophan concentrations. The strain was able to produce siderophore, and its production was significantly decreased with increasing Fe(III) citrate concentrations in the medium. The endophytic fungal strain also showed production of organic acids and phosphate solubilization activity. Plant growth-promoting effects of the strain were evaluated on in vitro seedling growth of Allium tuberosum. Application of 40% culture dilution resulted in a significant increase in root and shoot length, i.e., 24.03 ± 2.71 mm and 37.27 ± 1.86 mm, respectively, compared to nontreated control plants. The fungal endophyte Ld-03 demonstrated the potential of conferring disease resistance and plant growth promotion. Therefore, we conclude that the isolated Acremonium sp. Ld-03 should be further investigated before utilization as a biocontrol agent and plant growth stimulator.

Auxin-Regulated Lateral Root Organogenesis.

Plant fitness is largely dependent on the root, the underground organ, which, besides its anchoring function, supplies the plant body with water and all nutrients necessary for growth and development. To exploit the soil effectively, roots must constantly integrate environmental signals and react through adjustment of growth and development. Important components of the root management strategy involve a rapid modulation of the root growth kinetics and growth direction, as well as an increase of the root system radius through formation of lateral roots (LRs). At the molecular level, such a fascinating growth and developmental flexibility of root organ requires regulatory networks that guarantee stability of the developmental program but also allows integration of various environmental inputs. The plant hormone auxin is one of the principal endogenous regulators of root system architecture by controlling primary root growth and formation of LR. In this review, we discuss recent progress in understanding molecular networks where auxin is one of the main players shaping the root system and acting as mediator between endogenous cues and environmental factors.

Development of a nitrogen-rich hyperbranched polymer as adsorbent for enrichment and determination of auxins in plants.

In this study, a novel nitrogen-rich hyperbranched polymer was designed and synthesized via one-step precipitation copolymerization strategy. As possessing the lone-pair-electron-containing nitrogen atoms and positive-charged amine groups, as well as π electron-conjugated system, the prepared polymer displayed a strong tendency to adsorb protons acid, and negative-charged and conjugated compounds according to acid-base interaction, electrostatic interaction, and π-π stacking interaction. Based on these properties, a novel approach for assembling the proposed polymer coupled with high-performance liquid chromatography was successfully employed for selective enrichment and determination of auxins in plants. The extraction and desorption conditions were evaluated and the limits of detection and the limits of quantification of the proposed method were in the range of 0.15-0.29 µg L-1 and 0.49-0.98 µg L-1 for the four auxins based on the signal-to-noise ratio of 3:1 and 10:1, respectively. The recoveries of the target auxins from spiked plant samples were in the range from 85.0 to 116.3% with relative standard deviations lower than 9.6%. This study presented an inspiring thought for the construction of the versatile polymer adsorbent with highly efficient capturing of analytes from complex samples. Graphical abstract.

Disposable stainless steel-based electrochemical microsensor for in vivo determination of indole-3-acetic acid in soybean seedlings.

In vivo detecting of plants signal molecules is of great importance for the precision farming, crop management and plant phenotyping. In this work, for in vivo detecting indole-3-acetic acid (IAA), one of phytohormones, fine stainless steel (SS) wire was used as electrode material. Highly ordered nanopores, popcorn-like Au nanostructures, Pt nanoparticles and reduced graphene oxide (ERGO) nanocomposite films, and polymerized ST film (PST) were fabricated on the SS microelectrode in turn for improving the detection effect. Using the as-prepared SS microelectrode as working electrode, two untreated SS wires as reference electrode and counter electrode respectively, a disposable electrochemical microsensor for IAA were developed. The microsensor exhibited excellent selectivity and high sensitivity with low detection limit (LOD) of 43 pg mL-1. The limit of quantity (LOQ) is 143 pg mL-1. The RSD was 7% for 12 different PST/Pt-ERGO/Au/a-SS microsensors in presence of 100 µg mL-1 IAA. Using this microsensor, IAA of the stem of soybean seedlings was detected in vivo under salt stress. Our result was also confirmed by ultra-performance liquid chromatography-mass spectrum (UPLC-MS). This is the first report for the in vivo detection of IAA in plants using SS-based electrochemical microsensor. Our sensor provides an excellent sensing platform for detecting IAA in plants in vivo.

ZIF-8@SiO2 core-shell microsphere extraction coupled with liquid chromatography and triple quadrupole tandem mass spectrometry for the quantitative analysis of four plant growth regulators in navel oranges.

Monodisperse silica spheres that comprised a rhombic-dodecahedral zeolitic imidazolate framework core-shell microsphere were applied in the sample pretreatment of navel orange. A rapid and efficient liquid chromatography with triple quadrupole tandem mass spectrometry method was established for simultaneously quantifying four plant growth regulators, 6-benzylaminopurin, indole-3-acetic acid, indolepropionic acid, 3-indolebutyric acid, in navel oranges. A satisfactory result was obtained, i.e., the peak area of the four plant growth regulators against concentration was linear with good correlation coefficients of 0.99987-0.99991. Under optimized conditions, the limits of detection were 3.0-59.4 µg/L for the four plant growth regulators. This method was applied to the simultaneous analysis of the four plant growth regulators in commercial samples, and all the detections were confirmed by acquiring transitions for each pesticide in the samples.

Preparation of a new cellulose magnetic molecularly imprinted polymer micro-spheres to extract and analyze the indole-3-acetic acid in plant tissues.

The plant hormone auxin plays a fundamental role in the growth and development of plants. However, because of its low concentration and many other interfering substances in plant tissues, the determination of auxins is still a challenging problem. To solve this problem, a kind of novel cellulose magnetic molecularly imprinted polymer micro-spheres (CMMIPs) was prepared by entrapment technique in this study. The Fe3O4 paramagnetic particles acted as the core and were modified by cellulose, silanized ß-Cyclodextrin (ß-CD) and 4-Vinylpyridine (4-VP), were adopted for the specific selective recognition cavities. The CMMIPs were characterized with scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). High performance liquid chromatography (HPLC) was used for the determination of IAA in plant tissues. Based on the evaluations, the results showed that the CMMIPs possess porous surface appearance, narrow range particle size distribution and fine roundness. The sizes of most CMMIPs were within the range of 50-180 µm. And they can extract IAA more efficiently than those cellulose magnetic non-imprinted polymer micro-spheres (CMNIPs). CMMIPs can be recycled and preserved for a long time. Effective linear ranges for IAA was in the range of 1.00-100.0 µg L-1, and the effective detection limits was 4.5 µg L-1. The adding standard recovery was about 95%, and the relative standard deviations (RSD) was <5% for standard sample. The performance analysis was also estimated by seeds from three different plants, pea, rice and wheat. Recoveries were ranging from 73.2-80.1%, and the RSDs were from 3.8% to 13.3%. The results show that it was a reliable analytical method based on CMMIPs extraction combined with HPLC.

An ionic liquid functionalized graphene adsorbent with multiple adsorption mechanisms for pipette-tip solid-phase extraction of auxins in soybean sprouts.

A new ionic liquid functionalized graphene-pipette-tip solid-phase extraction method coupled with high-performance liquid chromatography was established for the simultaneous extraction and determination of three auxins in soybean sprouts. The graphene adsorbent, with multiple adsorption mechanisms, was first synthesized by functional modification of pentafluorobenzyl imidazolium bromide ionic liquid through thiol-ene click chemistry. The ionic liquid was applied to prevent the aggregation of graphene; it also imbued graphene with the ability for π-π interactions, ionic exchange, electrostatic interactions, as well as hydrogen bonding (which is stronger than the interaction between water and analytes), by augmenting the adsorption mechanisms between the adsorbent and analytes. Under optimized conditions, linearity was achieved in the ranges 0.03-5.00 µg/g for indole-3-acetic acid and 1-naphthaleneacetic acid and 0.09-5.00 µg/g for 2,4-dichlorophenoxyacetic acid, with a detection limit of 0.004-0.026 µg/g; this adsorbent has been successfully applied for the determination of auxins in soybean sprouts.

Chemical investigation of metabolites produced by an endophytic fungi Phialemonium curvatum from the leaves of Passiflora edulis.

Phialemonium curvatum, an endophytic fungus isolated from the leaves of Passiflora edulis was cultured in potato dextrose broth (PDB) media and chromatographic separation of the EtOAc extract of the broth and mycelium led to the isolation of 4-hydroxybenzoic acid (1), 3-indole acetic acid (2), solaniol (3), uracil (4), uridine (5) and glycerol (6). Compound 2 showed a weak antifungal activity against Cladosporium cladosporioides. This is the first report of the isolation of the endophytic fungus P. curvatum from P. edulis and complete 13CNMR assignments of 3.

Chemical characterization of cytotoxic indole acetic acid derivative from mulberry fruit (Morus alba L.) against human cervical cancer.

The fruit of the white mulberry tree (Morus alba L.) is a multiple fruit with a sweet flavor commonly consumed around the world. Chemical investigation of the fruits led to the isolation of two indole acetic acid derivatives (1 -2) including a new compound, which turned out to be an isolation artifact, 3S-(ß-D-glucopyranosyloxy)-2,3-dihydro-2-oxo-1H-indole-3-acetic acid butyl ester (1), along with five known compounds (3 -7). Compounds 2 and 7 were newly identified from mulberry fruit. The new isolation artifact (1) exhibited cytotoxic effect on human cervical cancer Hela cells in a dose-dependent manner. Compound 1 activated caspase-8, caspase-9, and caspase-3, followed by cleavage of PARP, a substrate of caspase-3, in a dose-dependent manner. Simultaneous alterations in protein expression of mitochondrial factors Bax, BID and Bcl-2 were also observed. A comparison between compounds 1 and 2 led to a structure-activity relationship analysis of the cytotoxic effect. These results suggest that compound 1 could be beneficial in human cervical cancer treatment, and provide a theoretical basis for further application of compound 1.

Multipoint recognition of domoic acid from seawater by dummy template molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography.

Due to the high cost of domoic acid (DA), different carboxylic acid compounds including indole-3-acetic acid (IAA), pyrrole-2-formic acid (PFA), pyridine-2,3-dicarboxylic anhydride (PDA), trimesitinic acid (TA) and citric acid (CA) were investigated as dummy templates for the molecularly imprinted solid-phase extraction (MISPE) for selective isolation and pre-concentration of an amnesic shellfish poison (ASP), DA. The highest binding amount of the polymers towards DA was obtained when CA was used as dummy template owing to its high hydrophilicity. In addition, the "four-point" recognition site constructed by three COOH groups and a OH group in CA was also speculated to be the reason for the high binding amount of CA-MIPs and the rebinding of DA can be depend on the three COOH groups and a NH group with conformational change in the recognition process. Finally, the CA-MISPE column was chosen for DA isolation and pre-concentration and effective result was obtained with recoveries higher than 90% and relative standard deviation (RSD) less than 5% (n=3). This new polymer can be effectively applied to the monitoring and predicting the existence of trace DA.

Analytical Determination of Auxins and Cytokinins.

Parallel determination of auxin and cytokinin levels within plant organs and tissues represents an invaluable tool for studies of their physiological effects and mutual interactions. Thanks to their different chemical structures, auxins, cytokinins and their metabolites are often determined separately, using specialized procedures of sample purification, extraction, and quantification. However, recent progress in the sensitivity of analytical methods of liquid chromatography coupled to mass spectrometry (LC-MS) allows parallel analysis of multiple compounds. Here we describe a method that is based on single step purification protocol followed by LC-MS separation and detection for parallel analysis of auxins, cytokinins and their metabolites in various plant tissues and cell cultures.

Monitoring of Crosstalk Between Jasmonate and Auxin in the Framework of Plant Stress Responses of Roots.

Over the last few years, it became more and more evident that plant hormone action is to great parts determined through their sophisticated crosstalk, rather than by their isolated activities. Thus, the parallel analysis of interconnected phytohormones in only very small amounts of tissue developed to an important issue in the field of plant sciences. In the following, a highly sensitive and accurate method is described for the quantitative analysis of the plant hormones jasmonic acid and indole-3-acetic acid in the model plant Arabidopsis thaliana. The described methodology is, however, not limited to the analysis of Arabidopsis samples but can also be applied to other plant species. The presented method is optimized for the working up of as little as 20-50 mg of plant tissue. Thus, it is well suited for the analysis of plant hormone contents in plant tissue of only little biomass, such as roots. The presented protocol facilitates the implementation of the method into other laboratories that have access to appropriate laboratory equipment and comparable state-of-the-art gas chromatography-mass spectrometry (GC-MS) technology.

ArgTX-636, a polyamine isolated from spider venom: A novel class of melanogenesis inhibitors.

To discover new molecules with an inhibitory activity of melanogenesis a hundred of scorpions, snakes, spiders and amphibians venoms were screened for their capacity to inhibit mushroom tyrosinase using 3,4-l-dihydroxyphenylalanine (l-DOPA) as substrate. The Argiope lobata spider venom proved to be the most active. HPLC fraction containing Argiotoxine-636 (ArgTX-636), a polyamine known for its numerous biological activities, was found to also show a good regulation activity of melanogenesis by inhibiting DOPA and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) oxidases activities, wore by tyrosinase (TYR) and tyrosinase-related protein 1 (TRP-1), respectively. Our results demonstrate that ArgTX-636 reduced the mushroom tyrosinase activity in a dose-dependent way with a maximal half inhibitory concentration (IC50) value of 8.34µM, when l-DOPA is used as substrate. The Lineweaver-Burk study showed that ArgTX-636 is a mixed type inhibitor of the diphenolase activity. Moreover, ArgTX-636 inhibits DHICA oxydase activity of mushroom tyrosinase activity with IC50 at 41.3µM. ArgTX-636 has no cytotoxicity in B16F10 melanoma cells at concentrations up to 42.1µM. The effect of ArgTX-636 on melanogenesis showed that melanin production in B16F10 melanoma cell decreased by approximatively 70% compared to untreated cells. ArgTX-636 displayed no significant effect on the TYR expression while the protein level of TRP-1 decreased in B16F10 cells. Thus, ArgTX-636 could have particular interest for cosmetic and/or pharmaceutical use in order to reduce important dermatoses in black and mixed skins.

Simultaneous extraction and HPLC determination of 3-indole butyric acid and 3-indole acetic acid in pea plant by using ionic liquid-modified silica as sorbent.

In this study, ionic liquid-modified silica was used as sorbent for simultaneous extraction and preconcentration of 3-indole butyric acid and 3-indole acetic acid in pea plants. The effect of some parameters such as pH and ionic strength of sample solution, amount of sorbent, flow rate of aqueous sample solution and eluent solution, concentration of eluent solution, and temperature were studied for each hormone solution. Percent extraction of 3-indole butyric acid and 3-indole acetic acid was strongly affected by pH of aqueous sample solution. Ionic strength of aqueous phase and temperature showed no serious effects on extraction efficiency of studied plant hormones. Obtained breakthrough volume was 200mL for each of studied hormones. Preconcentration factor for spectroscopic and chromatographic determination of studied hormones was 100 and 4.0×10(3) respectively. Each solid sorbent phase was reusable for almost 10 times of extraction/stripping procedure. Relative standard deviations of extraction/stripping processes of 3-indole butyric acid and 3-indole acetic acid were 2.79% and 3.66% respectively. The calculated limit of detections for IBA and IAA were 9.1×10(-2)mgL(-1) and 1.6×10(-1)mgL(-1) respectively.

Screening and characterization of endophytic Bacillus and Paenibacillus strains from medicinal plant Lonicera japonica for use as potential plant growth promoters

Abstract A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production). The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L) and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h). Strain 170 had the highest indoleacetic acid (IAA) production (49.2 mg/L) and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase) activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase). The six endophytic bacterial strains were identified to be Paenibacillus and Bacillus strains based on the results of 16S rRNA gene sequencing analysis and their physiological and biochemical characteristics. Results indicate the promising application of endophytic bacteria to the biological control of pathogenic fungi and the improvement of wheat crop growth.

An ultrahigh-performance liquid chromatography method with electrospray ionization tandem mass spectrometry for simultaneous quantification of five phytohormones in medicinal plant Glycyrrhiza uralensis under abscisic acid stress.

An efficient simplified method was developed to determine multiple classes of phytohormones simultaneously in the medicinal plant Glycyrrhiza uralensis. Ultrahigh-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS) with multiple reaction monitoring (MRM) in negative mode was used for quantification. The five studied phytohormones are gibberellic acid (GA3), abscisic acid (ABA), jasmonic acid (JA), indole-3-acetic acid, and salicylic acid (SA). Only 100 mg of fresh leaves was needed, with one purification step based on C18 solid-phase extraction. Cinnamic acid was chosen as the internal standard instead of isotope-labeled internal standards. Under the optimized conditions, the five phytohormones with internal standard were separated within 4 min, with good linearities and high sensitivity. The validated method was applied to monitor the spatial and temporal changes of the five phytohormones in G. uralensis under ABA stress. The levels of GA3, ABA, JA, and SA in leaves of G. uralensis were increased at different times and with different tendencies in the reported stress mode. These changes in phytohormone levels are discussed in the context of a possible feedback regulation mechanism. Understanding this mechanism will provide a good chance of revealing the mutual interplay between different biosynthetic routes, which could further help elucidate the mechanisms of effective composition accumulation in medicinal plants.

A new oxathiolane from Enterobacter cloacae.

Enterobacter cloacae is a versatile bacterial species inhabiting a wide variety of niches and is capable of metabolising a wide variety of substances as energy resources. The fermentation culture of this bacterial species has successfully yielded one new compound, Rimboxa (1) and three known compounds, i.e. indole-3-carboxaldehyde (2), indole-3-acetic acid (3) and 3,4-di-t-butylaniline (4). Rimboxa (1) is shown to possess the 1,2-oxathiolane core structure. 3,4-Di-t-butylaniline (4) is isolated for the first time from a natural resource. These compounds were isolated and characterised using extensive chromatographic and spectroscopic methods, and were subjected to cytotoxicity evaluations.

[SYNTHESIS OF PHYTOHORMONES BY NOCARDIA VACCINII IMV B-7405--PRODUCER OF SURFACTANTS].

AIM: To study the synthesis of phytohormones (auxins, cytokinins, abscisic acid) under cultivation of Nocardia vaccinii IMV B-7405 (surfactants producer) in media containing different carbon sources (glycerol, refined sunflower oil, as well as waste oil after frying potatoes and meat). METHODS: Phytohormones were extracted from supernatants of culture liquid (before or after surfactant separation) by ethylacetate (auxins, abscisic acid) and n-butanol (cytokinins), concentrated and purified by thin-layer chromatography, then quantitative determination was performed using a scanning Sorbfil spectrodensitometer. RESULTS: While growing in medium with refined oil IMV B-7405 strain synthesized 1.8 ± 0.09 g/l extracellular surfactant, also maximum amount of auxins (245-770 µ/l) and cytokinins (134-348 µl). Cultivation of N. vaccini LMV B-7405 on waste oil was accompanied by decreasing amount of phytohormones to 23-84 µ/l (auxins) and 16-90 µ/l (cytokinins) and increasing surfactant concentration to 2.3-2.6 g/l. The level of abscisic acid synthesis was practically not dependent on the nature of growth substrate, was substantially lower than that of auxins and cytokinins and ranged from 2 to 12 µ/l. CONCLUSIONS: Obtained data demonstrate the possibility of using oil-containing industrial waste for the simultaneous synthesis of both surfactants and phytohormones, and indicate the need for studies of the effect of producer cultivation conditions on the biological properties of the target products of microbial synthesis.

The morphology and bioactivity of the rice field cyanobacterium Leptolyngbya.

The genus Leptolyngbya comprises filamentous cyanobacteria that are important in rice fields. In the rhizosphere, cyanobacteria produce a variety of secondary metabolites such as auxins that are important in agriculture soil performance. To assess this, Leptolyngbya strain MMG-1, was isolated from the rhizosphere of rice plants and described. For this, the morphology of this strain was studied by light microscopy as well as by confocal laser scanning microscopy. Besides, the ability of this strain to synthesize an auxin-like bioactive com- pound was demonstrated under various culture conditions (different amounts of tryptophan; pH; different alter- nating light:dark periods; duration of the incubation). The auxin-like compound was extracted from the culture of Leptolyngbya strain MMG-1 and identified as indole-3-acetic acid (IAA) by thin layer chromatography (TLC) as well as by high performance liquid chromatography (HPLC). Our results showed that the strain required the precursor L-tryptophan for the synthesis of IAA. Leptolyngbya strain MMG-1 accumulated IAA intracellularly. The IAA secreted by Leptolyngbya strain MMG-1 was significantly correlated with the initial concentration of L-tryptophan in the medium, as well as with the duration of the incubation. The bioactivity of the secreted IAA was determined by its effect on the rooting pattern of Pisum sativum seedlings. The culture supernatant of Leptolyngbya strain MMG-1 stimulated the seedling lateral rooting, while it decreased root length. Hence, rhizospheric Leptolyngbya produced auxin under different conditions and affected the plants rooting pattern.