Harnessing Green Electricity from Food: A Split Black Gram-Based Triboelectric Nanogenerator for a Self-Powered Autonomous Lighting System and Portable Electronics.

Triboelectric nanogenerators (TENGs) represent a promising solution to mounting environmental concerns associated with battery disposal amid the escalating demand for portable electronics. However, prevailing TENG fabrication predominantly relies on nonbiodegradable, nonbiocompatible, and synthetic materials, posing a grave ecological threat. To mitigate this, there is a pressing need to develop eco-friendly and green TENGs leveraging sustainable, naturally occurring materials. This study pioneers the use of split black gram (SBG) as a tribo-positive material for TENGs. SBG's effectiveness as a tribo-positive material stems from its abundance of oxygen-containing functional groups, as confirmed by FTIR analysis, facilitating electron donation during the triboelectric process. SBG offers compelling advantages, including widespread availability, cost-effectiveness, biodegradability, and hydrophobic and adhesive properties due to its richness in starch and protein, positioning it as an optimal choice for eco-conscious TENG manufacturing. The fabrication process of an SBG-TENG is not only economical and facile but also solvent-free, requiring no specialized tools. Demonstrating commendable performance, the SBG-TENG achieves a maximum power density of 15.36 µW/cm2 at 1 MΩ, with an open circuit voltage of 84 V and short circuit current of 28 µA, comparable to recent studies. In practical applications, the SBG-TENG seamlessly integrates with LEDs and portable electronic devices via a full bridge rectifier, successfully powering them postcapacitor charging. Moreover, an autonomous lighting system is developed by embedding the SBG-TENG in a foot mat, enabling wireless light control through human stepping on the mat, introducing power-saving functionality for residential and office environments. In essence, the introduction of the SBG-TENG not only delivers cost-effectiveness but also minimizes the environmental impact by harnessing sustainable energy from food sources.

Effect of illite on the mechanical properties of subgrade soil under varying surcharge loads.

Due to its non-expanding properties, presence of Illite mineral in subgrade soil is investigated particularly on California bearing ratio (CBR), resilient modulus (MR) and swell potential. Multiple samples of stiff and weak subgrade soils with varying illite percentages were tested under six different surcharge loads ranging from 2.27 to 13.8 kg. Mineralogical analysis is performed using X-ray diffractometer and MR of soil is assessed using Ultrasonic pulse velocity (UPV) technique. Results showed a positive correlation between Illite percentage and both CBR and MR value. The soil with higher Illite content tends to exhibit higher CBR and MR values while those with higher montmorillonite content show lower values even with more Illite content. The CBR and MR values increases from 8.4% to 19 % and 139 MPa-315 MPa for stiff soil and 3.8%-11.7 % and 23 MPa-83 MPa for weak soil, respectively when the surcharge load was increase from to 2.27-13.8 kg. Additionally, a decrease in swell potential was observed from 1.64% to 1.09 % for stiff soil and 1.39%-0.84 % for weak soil with an increase in Illite percentage. The study also developed an improved relationship for predicting resilient modulus based on CBR value, showing a strong correlation with equations developed by many researchers in the past.

Predicting resilient modulus: A data driven approach integrating physical and numerical techniques.

Resilient modulus (MR) is an important parameter in the design of pavement that helps to characterize the quality of sub-grade materials. Generally, it is not determined experimentally due to time consuming, uneconomical, laborious and lack of advanced equipment in many laboratories. The aim of this research is to determine MR values using experimental (Ultrasonic pulse velocity (UPV) and Cyclic Triaxial) and Artificial neural network (ANN) techniques. For experimental study twenty-four soil samples comprising of coarse and fine-grained soils were collected from different locations. For ANN modelling, Input variables comprised of essential soil Atterberg limits (liquid limit, plastic limit, plasticity index) and compaction properties (maximum dry density, optimum moisture content). The validation of ANN model is done by comparing its results with the experimentally evaluated MR from UPV and Cyclic Triaxial test. Experimental results showed that Cyclic Triaxial test yielded resilient modulus value that was 5 % more than obtained from the UPV test. Moreover, results showed that modulus of resilience (MR) values determined by UPV, and artificial neural network (ANN) modelling have significant closeness with the cyclic triaxial results of resilient modulus; thus, making it a significant development in predicting resilient modulus efficiently.

Single-Cell-Driven Tri-Channel Encryption Meta-Displays.

Multi-functional metasurfaces have attracted great attention due to the significant possibilities to realize highly integrated and ultra-compact meta-devices. Merging nano-printing and holographic information multiplexing is one of the effective ways to achieve multi-functionality, and such a merger can increase the information encoding capacity. However, the current approaches rely on stacking layers and interleaving, where multiple resonators effectively combine different functionalities on the cost of efficiency, design complexity, and challenging fabrication. To address such challenges, a single meta-nanoresonator-based tri-functional metasurface is proposed by combining the geometric phase-based spin-decoupling and Malus's law intensity modulation. The proposed strategy effectively improves information capacity owing to the orientation degeneracy of spin-decoupling rather than layer stacking or super-cell designs. To validate the proposed strategy, a metasurface demonstrating two helicity-dependent holographic outputs is presented in far-field, whereas a continuous nano-printing image is in near-field. It is also employed on CMOS-compatible and cost-effective hydrogen amorphous silicon providing transparent responses for the whole visible band. As a result, the proposed metasurface has high transmission efficiency in the visible regime and verifies the design strategy without adding extra complexities to conventional nano-pillar geometry. Therefore, the proposed metasurface opens new avenues in multi-functional meta-devices design and has promising applications in anti-counterfeiting, optical storage and displays.​.

A Systematic Design Optimization Approach for Multiphysics MEMS Devices Based on Combined Computer Experiments and Gaussian Process Modelling.

This paper presents a systematic and efficient design approach for the two degree-of-freedom (2-DoF) capacitive microelectromechanical systems (MEMS) accelerometer by using combined design and analysis of computer experiments (DACE) and Gaussian process (GP) modelling. Multiple output responses of the MEMS accelerometer including natural frequency, proof mass displacement, pull-in voltage, capacitance change, and Brownian noise equivalent acceleration (BNEA) are optimized simultaneously with respect to the geometric design parameters, environmental conditions, and microfabrication process constraints. The sampling design space is created using DACE based Latin hypercube sampling (LHS) technique and corresponding output responses are obtained using multiphysics coupled field electro-thermal-structural interaction based finite element method (FEM) simulations. The metamodels for the individual output responses are obtained using statistical GP analysis. The developed metamodels not only allowed to analyze the effect of individual design parameters on an output response, but to also study the interaction of the design parameters. An objective function, considering the performance requirements of the MEMS accelerometer, is defined and simultaneous multi-objective optimization of the output responses, with respect to the design parameters, is carried out by using a combined gradient descent algorithm and desirability function approach. The accuracy of the optimization prediction is validated using FEM simulations. The behavioral model of the final optimized MEMS accelerometer design is integrated with the readout electronics in the simulation environment and voltage sensitivity is obtained. The results show that the combined DACE and GP based design methodology can be an efficient technique for the design space exploration and optimization of multiphysics MEMS devices at the design phase of their development cycle.

Optical spin-symmetry breaking for high-efficiency directional helicity-multiplexed metaholograms.

Helicity-multiplexed metasurfaces based on symmetric spin-orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.

Gradient-based impedance synthesis for breast and lung cancer cell screening deploying planar and nano-structured electrodes.

World Health Organization articulated 9.8 million casualties globally in 2018 due to cancer. Cancer, as the world's second most fatal disease, can be recuperated well if diagnosed at an early stage. In this work, a gradient-based impedance synthesis of normal and cancerous cells of breast and lungs, is demonstrated numerically for early-stage cancer detection. Low-voltage single-cell level examination is employed for indomitable diagnosis. MCF-7 and MCF-10A are utilized as breast cancer and breast normal cells, respectively; likewise, SK-MES and NL-20 are utilized as lung cancer and lung normal cell. Pre-examination numerical setup validity ensured with multiple test regimes. Micro-scaled planar and nano-structured electrodes are employed individually to witness the effect of the electrode's structure during electrical impedance examination of cancer and non-cancer cell. Frequency range, at which differential impedance effect is found detectable, for breast and lung cancer cell pairs is determined to be 107 Hz and 108 Hz, respectively. By surpassing the conventional impedance spectroscopy with tedious data fitting formalities, the gradient synthesis technique for cancer detection is introduced. The gradient synthesis for cancer detection is found independent of electrode shape effect. Gradient for breast cancer cell is found to be 2 times greater than the normal breast cell while for lung cancer cell it is found to be 1.5 times greater than the normal lung cell. Our results suggest that as the frequency of applied electrical stimulus increases, impedance of cancerous cell falls at the rate almost double than its counterpart normal cell. This work provides a theoretical basis for further experimental exploration of gradient-based impedance synthesis in cancer therapy and serves as a design tool for performance optimization. Figure 1 (a) Represents electrical Impedance analysis of breast normal cell MCF-10A and breast cancer cell MCF-7 using micro-scaled planar and nano-structured electrodes. (b) Gradient impedance synthesis performed, for breast normal cell (MCF-10A) and breast cancer cell (MCF-7) likewise for lungs normal cell (NL-20) and lungs cancer cell (SK-MES), which assures clear differential effect for cancer screening. Surpassing the conventional and tedious data fitting impedance spectroscopies, a novel gradient-based impedance spectroscopy for early cancer detection is introduced. It clearly detects cancer without any data fitting formalities to find parameter of identification. Planar and nano structure electrodes are used to witness the impact of electrode shape on cell impedance. Breast normal MCF-10A and cancer cell MCF-7 as well as lungs normal NL-20 and cancer cell SK-MES are examined to reflect the efficacy of our work. Single cell level examination is performed for authenticated results.

Single-layered meta-reflectarray for polarization retention and spin-encrypted phase-encoding.

Broadband communication with high data rates is a dire need for state-of-the-art wireless technologies. For achieving efficient wireless communication (particularly in an indoor environment), the electromagnetic (EM) waves should maintain their state of polarization despite encountering multiple reflections. Metasurfaces provide a unique platform to design subwavelength-featured meta-reflectarrays which enable the desired retention of the polarization state of an EM wave upon reflection. We present a single-layered broadband meta-reflectarray, simultaneously breaking n-fold (n > 2) rotational and mirror symmetry, which exhibits an unprecedented control over the phase, amplitude, and polarization of a reflected EM wave. This unique control enables the retention of polarization state and recording of spin-encrypted information for the reflected EM waves. Such novel multifunctional meta-reflectarray can be crucial to building an indoor setup for high data rate wireless communications. Meanwhile, the meta-array's ability to encode phase information provides an extra degree of freedom to structure and control (via incident spin) the reflected EM beam in the desired way. For the proof of concept, we have experimentally demonstrated a spin-encrypted holographic display which reconstructs the recorded holographic image at an image plane for the left circularly polarized (LCP) illumination and exhibits circular dichroism for the right circularly polarized (RCP) incident waves. The proposed meta-array can find applications in 5G indoor wireless communication, chiral sensing, spin-selective imaging, holography, and encryption.

Engineering multimodal dielectric resonance of TiO2 based nanostructures for high-performance refractive index sensing applications.

Optical metasurface based refractive index (RI) sensors find applications in chemical, environmental, biomedical, and food processing industries. The existing RI sensors based on metals suffer from the plasmonic loss in the optical regime; in contrast, those based on Fano-type resonances generated by dielectric materials are either polarization-sensitive or are based on complex geometrical structures prone to fabrication imperfections that can lead to severe performance degradation. Here, we demonstrate that careful engineering of resonance modes in dielectric metasurfaces based on simple symmetric meta-atoms can overcome these limitations. More specifically, we have designed low-loss high-performance RI sensors using all-dielectric metasurfaces composed of TiO2 based nanostructures of three different shapes (i.e., cylindrical, square and elliptical) operating at near-infrared (NIR) wavelengths, which are robust against the perturbations of geometric parameters. In terms of physics, this work reports sensor structures achieving sharp resonant dips of high Q-factor in the transmission spectra corresponding to multiple dielectric resonance modes (i.e., electric quadrupole, magnetic dipole, and electric dipole) with superior performance as compared to the state-of-the-art. Four absolute liquids (water, ethanol, pentanol, and carbon tetrachloride) with a refractive index ranging from 1.333 to 1.453 are used to numerically validate the performance, and a maximum sensitivity of 798 nm/RIU with FOM up to 732 has been achieved.

Complete Genome Sequence of the Type Strain Pectobacterium punjabense SS95, Isolated from a Potato Plant with Blackleg Symptoms.

Pectobacterium punjabense is a newly described species causing blackleg disease in potato plants. Therefore, by the combination of long (Oxford Nanopore Technologies, MinION) and short (Illumina MiSeq) reads, we sequenced the complete genome of P. punjabense SS95T, which contains a circular chromosome of 4.793 Mb with a GC content of 50.7%.

Species Diversity of Dickeya and Pectobacterium Causing Potato Blackleg Disease in Pakistan.

Potato blackleg is caused by a diverse species of pectinolytic bacteria. In Pakistan, approximately 90% of the pathogens involved belong to Pectobacterium atrosepticum. Survey (2014 to 2017), sampling, and isolation from different potato growing areas of Punjab, Pakistan depicted an overall disease incidence of approximately 15%. Thirty-six pectinolytic strains confirmed through biochemical and pathogenicity testing were characterized via gapA gene to identify them at the species level. To further validate the identification, one strain from each species SS26 (P. atrosepticum), SS28 (Pectobacterium polaris), SS70 (Dickeya dianthicola), SS90 (Pectobacterium parmentieri), SS95 (Pectobacterium punjabense), and SS96 (Pectobacterium versatile) were selected for draft genome sequencing and multilocus sequence analysis of 13 housekeeping genes (fusA, rpoD, acnA, purA, gyrB, recA, mdh, mtlD, groEL, secY, glyA, gapA, and rplB). Phylogenetic analysis revealed considerable genetic diversity in the genus Pectobacterium. In silico DNA-DNA hybridization and average nucleotide identity values of the strains selected for genome sequencing were determined with other reference Pectobacterium and Dickeya strains. Moreover, all six representative strains were also phenotypically characterized on the basis of metabolism of different carbon sources. Overall, on the basis of genotypic and phenotypic characteristics, these 36 isolates were grouped into six species: P. atrosepticum, P. versatile, P. parmentieri, P. polaris, P. punjabense, and D. dianthicola.

Hybrid analytical-numerical approach for investigation of differential effects in normal and cancer cells under electroporation.

Electroporation has offered important biomedical applications in electrochemotherapy, tissue ablation and gene editing recently. Time and computation efficient analytical and numerical models should be developed to understand the differential effects of electroporation on normal and cancer cells. In this work, we present a hybrid analytical-numerical approach to investigate the behavior of normal and cancer cells under electroporation. We have compared the human breast cancer cell (MCF-7) and non-tumorigenic human breast cell (MCF-10A) under electroporation in terms of change in transmembrane voltage and pore formation on cell surface. The effects of electric pulse time, amplitude and membrane conductivity variation are analyzed in a systematic manner. To accelerate the calculation of transmembrane voltage, we have introduced a simple Multilayer Electric Potential Model (MEPM) which calculates the potential distribution across the cell analytically. The MEPM calculates electric potential distribution across a biological cell sandwiched between two semi-circular electrodes held at fixed potential, by solving the Laplace's equation over an equivalent planar, multilayer geometry. The MEPM model is then used in a Finite Element Method (FEM) based numerical model of electroporation. Transmembrane voltage and pore density for electroporated MCF-10A are estimated to be 1.31 V and 2.98 × 1013 m-2 respectively, and for MCF-7 the estimated values are 0.53 V and 1.93 × 1014 m-2, respectively. Our results suggest that under electroporation, the cancer cell's membrane get much more permeabilized than its counterpart normal cell even at small values of transmembrane voltage. This work provides a theoretical basis for further experimental exploration of electroporation process in cancer therapy, and serves as a design tool for performance optimization.

Pectobacterium punjabense sp. nov., isolated from blackleg symptoms of potato plants in Pakistan.

Pectobacterium isolates SS95T, SS54 and SS56 were collected from a potato field in the Chiniot district in the plains of the Punjab province, Pakistan. Sequencing of the gapA barcode revealed that these strains belong to a novel phylogenetic group separated from P.ectobacterium wasabiae and Pectobacterium parmentieri species. Furthermore, multilocus sequence analyses of 13 housekeeping genes (fusA, rpoD, acnA, purA, gyrB, recA, mdh, mtlD, groEL, secY, glyA, gapA and rplB) clearly distinguished the type strain, SS95T, from its closest relatives, i.e. P. parmentieri RNS 08-42-1AT and P. wasabiae CFBP3304T, as well as from all the other known Pectobacteriumspecies. In silico DNA-DNA hybridization (<44.1 %) and average nucleotide identity (<90.75 %) values of strain SS95T compared with other Pectobacterium type strains supported the delineation of a new species. Genomic and phenotypic comparisons permitted the identification of additional traits that distinguished the Pakistani isolates from all other known Pectobacterium type strains. The name Pectobacterium punjabense sp. nov. is proposed for this taxon with the type strain SS95T (=CFBP 8604T=LMG 30622T).

A novel combination of four flavonoids derived from Astragali Radix relieves the symptoms of cyclophosphamide-induced anemic rats.

By using a feedback system control scheme, the best combination of formononetin, ononin, calycosin, and calycosin-7-O-ß-d-glucoside derived from Astragali Radix was shown to activate a hypoxia response element, a regulator for erythropoietin (EPO) transcription, in kidney fibroblast. In cyclophosphamide-induced anemic rats, the treatment of combined flavonoids, or EPO, improved the levels of red blood cells, white blood cells, hemoglobin, and hematocrit. In addition, the altered levels of antioxidant capacity, super oxidase dismutase, and malondialdehyde, triggered in anemic rats, were restored to control levels by the treatment of flavonoids. Here, we proposed a possible therapy by using the common flavonoids in treating anemia.

Innovative solution to sharp waste management in a tertiary care hospital in Karachi, Pakistan.

BACKGROUND: Prevalence of hepatitis B and C in Pakistan is 2.5% and 4.5%, respectively. Major cause of these infections is reuse of syringes. OBJECTIVE: To determine a cost-effective, innovative solution to prevent syringe reuse and break the transmission cycle of blood-borne infections. STUDY DESIGN, SETTINGS, AND DURATION: Analytical study in a tertiary care hospital, Jinnah Postgraduate Medical Centre, Karachi, Pakistan, July 2011 to June 2012. METHODS: Healthcare workers from 30 wards included in the study were trained on injection safety, use of needle remover and needle pit, and management of needlestick injuries. Each ward was provided with 2 needle-removing devices, and a pit was constructed for disposal of needles. Usage of the device in wards and pit use were monitored regularly. RESULTS: In 28 (93.3%) wards, sharp containers were accessible by public and were slack. Syringes were recapped using both hands in 27 (90%) cases; needlestick injury was reported by 30% of paramedics, while 25 (83.3%) of the interviewed staff had not received any formal training in injection safety. Vigilant monitoring and information sharing led to healthcare workers in 28 (96.5%) wards using the device. Needle containers were emptied in 27 (93.1%) wards, and needle pits were used in 26 (96.3%) wards. Needlestick injury was nil in follow-up. CONCLUSIONS: Needle removers permanently disable syringes. The needle pit served as a cost-effective, innovative method for disposal of needles. The intervention resulted in reducing the risk of needlestick injury.

Synthesis, characterization, in vitro antimicrobial, and U2OS tumoricidal activities of different coumarin derivatives.

BACKGROUND: Coumarin and its derivatives are biologically very active. It was found that the enhanced activities are dependent on the coumarin nucleus. Biological significance of these compounds include anti-bacterial, anti-thrombotic and vasodilatory, anti-mutagenic, lipoxygenase and cyclooxygenase inhibition, scavenging of reactive oxygen species, and anti-tumourigenic. Our interest in medicinal chemistry of dicoumarol compounds have been developed by keeping in view the importance of coumarins along with its derivatives in medicinal chemistry. All the synthesized compounds were fully characterized by spectroscopic and analytical techniques and were screened for antimicrobial and U2OS bone cancer activities. RESULTS: 4-hydroxycoumarin was derivatized by condensing with different aldehydes yielding the dicoumarol and translactonized products. Elemental analyses, ESI(+,-) MS, 1H and 13C{1H}-NMR, infrared spectroscopy and conductance studies were used to characterize the synthesized compounds which revealed the dicoumarol and dichromone structures for the compounds. The compounds were screened against U2OS cancerous cells and pathogenic micro organisms. The compounds with intermolecular H-bonding were found more active revealing a possible relationship among hydrogen bonding, cytotoxicity and antimicrobial activities. CONCLUSION: Coumarin based drugs can be designed for the possible treatment of U2OS leukemia.

High factor XI, recurrent pregnancy loss, enoxaparin.

Of the 149 women with 0 pregnancy losses, 7 (5%) had factor XI level ≥150% versus 5 of 31 (16%) women with recurrent pregnancy loss. Three of the 5 women with high factor XI and recurrent pregnancy loss, with 19 previous pregnancy losses and 0 live births, were given enoxaparin during 5 subsequent pregnancies, and had 6 term live births and 1 miscarriage.

Determination of risk factors for hepatitis B and C in male patients suffering from chronic hepatitis.

BACKGROUND: Hepatitis B and C is common in Pakistan and various risk factors are attributable to its spread.One thousand and fifty consecutive male cases suffering from chronic liver disease (327 HBV and 723 HCV) were selected from the OPD of public sector hospital and a private clinic dealing exclusively with the liver patients. To compare the results 723 age and gender matched controls were selected from the blood transfusion services of the public sector hospital. A standard questionnaire was filled for all patients and controls which included the information on possible risk factors. FINDINGS: Family history of liver disease was significantly higher (43% and 34%) in HBV and HCV positive cases as compared to 5% in controls [odds ratio 15.6; 95% Confidence Interval CI: 10.1 - 24.1, 10.9; 95% Confidence Interval CI: 7.3 - 16.4] and same trend was seen for death due to liver disease in the family. Majority 74% hepatitis B positive cases had their shaves done at communal barbers but this practice was equally prevalent amongst controls (68%), thus negating it as a possible risk factor, but there is a significant risk with p < 0.05 associated with HCV in male that get their shave in barber. Very strong association of the disease was found with history of dental treatment (38% HCV 36% HBV and 21% controls) [Odd ratio 2.3; 95% CI: 1.8-3.0, Odd ratio 2.1; 95% CI: 1.5-2.8], surgery (23% HCV cases,14% HBV cases and 12% controls), history of blood transfusion was significantly higher in HCV (6%) as compared to controls (2.1%) [Odd ratio 2.9; 95% CI: 1.5-5.5]. History of taking injections for various ailments by the general practitioners (over 90% patients in both hepatitis B and C cases) was significantly higher as compared to 75% in controls [Odds ratio 3.8, 6.9; 95% CI: 2.4-6.1, 4.5-10.4] but hospitalization was not significant in HBV and HCV cases. CONCLUSION: Injections, surgery and dental treatment appear as major risk factors for the transmission of hepatitis B and C in the community. Massive health care awareness drives need to be done for both health care providers and the public to reduce this menace.

A metagenomic analysis of soil bacteria extends the diversity of quorum-quenching lactonases.

A metagenomic library of 10,121 clones, generated from bacteria inhabiting a pasture soil from France, was screened for the presence of fosmids conferring either N-acylhomoserine lactone (NAHL) synthesis or NAHL degradation ability upon their Escherichia coli host. No clone producing NAHLs was identified whereas one, containing a 31 972 bp insert in fosmid p2H8, allowed NAHL degradation. This led to the cloning and identification of a gene, qlcA, encoding an NAHL-lactonase activity, as judged by lactone-ring closure and HPLC/MS analyses of NAHL degradation products. The qlcA gene efficiently quenched quorum-sensing regulated pathogenic functions when expressed in Pectobacterium carotovorum. The QlcA peptide belongs to the family of zinc-dependent metallohydrolases and appears to be distantly related to other NAHL-lactonases discovered in Agrobacterium, Bacillus, Photorhabdus and Rhizobium. In-silico analysis of the metagenomic insert revealed the occurrence of 20 orf, with a constant GC% and codon usage, suggesting a unique bacterial origin. Nine out of these 20 orf were homologous to genes encoding biosynthesis of arginine; they were clustered with an unusual succession argFJADBCRGH. The fosmid p2H8 is able to complement the argA, argB and argC mutants in E. coli. Phylogenetic analysis showed that 9 orf out of 20 were related to sequences from members of the Acidobacteria, supporting the hypothesis that the analysed insert might be originated from an organism related to this phylum.