Pantoea conspicua promoted sunflower growth and engulfed rhizospheric arsenate by secreting exopolysaccharide.

A rhizobacterium, Pantoea conspicua, was examined against sunflower seedlings' growth under arsenate stress. Sunflower upon exposure to arsenate resulted in compromised growth that might be due to the accumulation of higher concentrations of arsenate and reactive oxygen species (ROS) in seedlings' tissues. The deposited arsenate led to oxidative damage and electrolyte leakage, making the sunflower seedlings vulnerable to compromise its growth and development. However, inoculation of sunflower seedlings with P. conspicua alleviated arsenate stress in host by initiating a multilayered defence mechanism. In fact, P. conspicua filtered out 75.1% of the arsenate from growth medium that were available to the plant roots in the absence of the said strain. To accomplish such activity, P. conspicua secreted exopolysaccharides as well as altered lignification in host roots. The arsenate (24.9%) that made its way to plant tissues was countered by helping the host seedlings to produce higher levels of indole acetic acid, non enzymatic antioxidants (phenolics and flavonoids) and antioxidant enzymes (catalase, ascorbte peroxidase, peroxidase, superoxide dismutase). As a result, ROS accumulation and electrolyte leakage were brought back to normal levels as observed in control seedlings. Hence, the rhizobacterium associated host seedlings achieved higher net assimilation (127.7%) and relative growth rate (113.5%) under 100 ppm of arsenate stress. The work concluded that P. conspicua alleviated arsenate stress in the host plants by imposing physical barrier as well as improving host seedlings' physiology and biochemistry.

Enhancement of chromate phytoremediation and soil reclamation potential of Brassica campestris L. by Aspergillus niger.

In the past decades, chromium contamination of agricultural land has become an emerging concern. For land reclamation, several strategies including bioremediation have been used. Owing the potential of hyperaccumulators, the current project aims to enhance the phytoremediation potential of Brassica campestris L. with the application of chromate tolerant endophytic fungus Aspergillus niger CSR3. when B. campestris was watered with chromate concentration (300, 500, and 1000 ppm) in the form of potassium chromate (K2CrO4), seed germination, hypocotyl length, root shoot length, and leaf area were severely reduced (p < 0.05). However, reproductive parts of the plants remained viable once initiated. Inoculation of the selected endophyte stimulated host growth, reducing the severity of the chromate stress. Interestingly, CSR3-inoculated plants accumulated 1.82-, 1.51-, and 2.16-fold greater quantities of chromate than the un-inoculated plants. To cope better with the stress, endophyte-associated host had stronger antioxidant system supported by enhanced production of nonenzymatic antioxidants (flavonoids, phenolics, and proline) and enzymatic antioxidants (SOD, CAT, APX, and POD) than the non-endophytes host plants. It may be concluded that hyperaccumulator B. campestris accumulates even higher quantities of chromate in the presence of endophytic A. niger CSR3 and tolerates elevated levels of chromate with boosted antioxidant system. Thus, hyperaccumulator host associated with heavy metal tolerant endophytic fungi can be the possible efficient way to reclaim the contaminated site from the heavy metals effectively in a short time period.

Phytohormones producing rhizobacteria alleviate heavy metals stress in soybean through multilayered response.

AIM: of the current research was to use plant growth promoting rhizobacteria for sequestration and biotransformation of the toxic form of Cr and As into non-toxic form. Remediating these contaminants using microbes is a common technique and rhizo-microbiota not only relieves metal stress but also acts as biofertilizers. Role of plant growth-promoting rhizobacterial (PGPR) strains Acinetobacter beijerinckii (C5) and Raoultella planticola (C9) in counteracting chromium and arsenic stress in soybean seedlings was assessed. The isolated rhizobacteria were able to tolerate excessive quantities (up to 1200 ppm) of chromate and arsenate in liquid media. Beside their growth in heavy metal containing media, the strains were able to bio-transform chromate and arsenate to their least toxic form. They released significant quantities of stress related metabolites including phenols, flavonoids, proline, sugars and protein even in the presence of 1200 ppm of the heavy metals. They also released several plant hormones together with indole-3-acetic acid (IAA), salicylic acid (SA) and gibberellins. Another important feature of the isolates was their ability to solubilize phosphate and release siderophores and exposure to different levels of the selected heavy metals enhanced phosphate solubilization potential of both the isolates by up to 2-fold. Release of siderophore in A. beijerinckii C5 was enhanced by increasing heavy metals concentration in the media but in case of R. planticola C9 a decline was noted. When inoculated on soybean seedlings, the isolates modulated several metabolites of the hos plant enabling them to combat heavy metal toxicity at different levels. The PGPR strains boosted host's antioxidants production which minimized the oxidative damage by scavenging excessive ROS produced under stress. Control plants showed upregulation of stress response metabolites compared to PGPR application, whereas, IAA and SA were significantly higher in PGPR associated seedlings. In conclusion, PGPR alters the physiological and metabolic responses of soybean enabling it to cope better with chromate and arsenic toxicity and grow well under the stress.

Biological synthesis of hybrid silver nanoparticles by Periploca aphylla Dcne. From nanotechnology to biotechnology applications.

Nanotechnology is one of the advanced technologies that have almost universal implications in every field of science. The importance is due to the unique properties of nanoparticles; however, green synthesized nanoparticles are considered eco-friendly. The current project was rationalized to prepare green-synthesized biogenic Periploca aphylla Dcne. silver nanoparticles (Pe-AgNPs) and poly (ethylene glycol) methacrylate coated AgNPs nanocomposites (PEGMA-AgNPs) with higher potential for their application in plant tissue culture for enhancing the biomass of Stevia rebaudiana calli. The increased biomass accumulation (17.61 g/3 plates) was observed on a medium containing virgin Pe-AgNPs 40th days after incubation, while the maximum increase was found by supplementing virgin Pe-AgNPs and PEGMA capped AgNPs (19.56 g/3 plates), compared with control (12.01 g/3 plates). In this study, PEGMA capped AgNPs supplementation also induced the maximum increase in total phenolics content (2.46 mg GAE/g-FW), total flavonoids content (3.68 mg QE/g-FW), SOD activity (53.78 U/ml protein), GSH content (139.75 µg/g FW), antioxidant activity (54.3 mg AAE/g FW), FRAP (54 mg AAE/g FW), and DPPH (76.3%) in S. rebaudiana calli compared with the control. It was concluded that virgin Pe-AgNPs and PEGMA capped AgNPs (hybrid polymer) are potent growth regulator agents and elicitors that can be exploited in the biotechnology field for growth promotion and induction of essential bioactive compounds and secondary metabolites from various commercially important and medicinally valuable plants such as S. rebaudiana without laborious field cultivation.

Stemphylium lycopersici and Stemphylium solani improved antioxidant system of soybean under chromate stress.

Ecologists around the world are giving great attention to the metal pollution of agronomic soil. Recently, several techniques have been employed to remediate heavy metals, but the use of microorganisms is cheap, less time-consuming, and easily available. In the current study, the endophytic strains, Cp1 and Cp2 were isolated from sterilized 1-5 cm long root and leaf segments of Chlorophytum comosum using Hagem media. To get pure colonies, the strains were repeatedly cultured on potato dextrose agar (PDA) media. The strains Cp1 and CP2 were identified as Stemphylium lycopersici and Stemphylium solani based on ITS sequencing and neighbor joining (NJ) method. Both strains showed a growth-promoting potential in soybean seedlings exposed to chromate (Cr) stress. Moreover, S. lycopersici and S. solani improved the Indole-3-acetic acid (IAA), flavonoids, phenolics, protein, and proline contents, whereas, lowered Salicylic acid (SA) production in the seedlings. The selected endophytic fungal strains also promoted the antioxidant system of soybean seedlings through enhanced production of ascorbic acid oxidase (AAO), catalases (CAT), peroxidase, and free radical scavenging enzymes. Both strains bio-transformed the toxic Cr-VI to less toxic Cr-III in the cultural filtrate as well as host plants. In fact, efficient uptake of Cr and its conversion by the isolated endophytic fungal strains could be used as a viable tool to remediate Cr contamination in agricultural soils.

Biological Synthesis of Silver Nanoparticles by Amaryllis vittata (L.) Herit: From Antimicrobial to Biomedical Applications.

The current study sought to synthesize silver nanoparticles (AgNPs) from Amaryllis vittata (L.) leaf and bulb extracts in order to determine their biological significance and use the toxic plants for human health benefits. The formation of silver nanoparticles was detected by a change in color from whitish to brown for bulb-AgNPs and from light green to dark brown for leaf-AgNPs. For the optimization of silver nanoparticles, various experimental physicochemical parameters such as pH, temperature, and salt were determined. UV-vis spectroscopy, Fourier transform infrared spectroscopy, X-ray dispersion spectroscopy, scanning electron microscopy, and energy dispersion spectroscopy analysis were used to characterize nanoparticles. Despite the fact that flavonoids in plant extracts were implicated in the reduction and capping procedure, the prepared nanoparticles demonstrated maximum absorbency between 400 and 500 nm. SEM analysis confirmed the preparation of monodispersed spherical crystalline particles with fcc structure. The bioinspired nanoparticles were found to show effective insecticidal activity against Tribolium castaneum and phytotoxic activity against Lemna aequincotialis. In comparison to plant extracts alone, the tested fabricated nanoparticles showed significant potential to scavenge free radicals and relieve pain. Antibacterial testing against human pathogenic strains, i.e., Escherichia coli and Pseudomonas aureginosa, and antifungal testing against Aspergillus niger revealed the significant potential for microbe resistance using AgNPs. As a result of the findings, the tested silver nanoparticles demonstrated promising potential for developing new and effective pharmacological and agricultural medications. Furthermore, the effects of biogenic AgNPs on an in vitro culture of Solanum tuberosum L. plants were investigated, and the findings indicated that bulb-AgNPs and leaf-AgNPs produced biomass and induced antioxidants via their active constituents. As a result, bulb-AgNPs and leaf-AgNPs may be recommended for use in Solanum tuberosum L. tissue culture for biomass fabrication and metabolic induction.

Hybridization of green synthesized silver nanoparticles with poly(ethylene glycol) methacrylate and their biomedical applications.

In the present research, a rapid, simple and efficient green method is used for the incorporation of silver nanoparticles (AgNPs) into poly(ethylene glycol) methacrylate (PEGMA) to create biocatalysts with excellent properties for pharmaceutical purpose. In the first phase, Caralluma tuberculata capped AgNPs (Ca-AgNPs) were prepared using green synthetic approach and in the second phase Caralluma tuberculata capped AgNPs were hybridized with poly(ethylene glycol) methacrylate to form PEGMA-AgNPs. Both the virgin (naked or uncapped) and polymer-capped materials were characterized spectroscopically and their results were compared. Fourier transform infrared spectroscopy showed no new peak after the capping procedure, showing that only physical interactions takes place during capping. After PEGMA capping, the spectra of the AgNPs red shifted (from 450 nm to 520 nm) and the overall particle size of AgNPs increased. Catalytic activity of the nanoparticles and hybrid system were tested by choosing the catalytic reduction of 4-nitrophenol (4-NP) as a model reaction. Both synthesized NPs and polymer capped NPs exhibits catalytic activity for the reduction of 4-NP to 4-aminophenol. The polymer hybrid exhibits remarkable antiproliferative, antioxidant, cytotoxic, antidiabetic and antileishmanial activities.

Comparative assessment of chromate bioremediation potential of Pantoea conspicua and Aspergillus niger.

The recent work aims at the use of Pantoea conspicua (MT5) and Aspergillus niger (CRS3) to assess their bioremediation potential and growth restoration of Helianthus annuus L. under chromate (Cr+6) stress. The growth of the P. conspicua and A. niger was tested in Cr+6 supplemented media. The strains can withstand up to 1200 and 900 ppm respectively in the media and effectively bio-transform it to nontoxic form. Supplemented metal's levels significantly decreased the growth attribute of H. annuus (p< 0.05). On the other hand, P. conspicua and A. niger rescued the host plant by establishing higher colonization frequency with the host roots. Moreover, MT5 bio-transformed the toxic Cr+6 to non-toxic Cr+3 form in the rhizosphere. It also enhanced the host plant growth by producing phytohormones and ceasing Cr uptake and accumulation. Contrarily, CRS3 tends to accumulate and bio-transform metal in their hyphae. Nonetheless, both of the microbes tend to modulate phytohormones production and strengthening antioxidant system of the host. Improvement in the antioxidant system enabled the host plant to produce higher phenolics and flavonoids, and lower peroxidase. The associated plant species also exhibited higher ROS scavenging and lower ROS accumulation. Besides, the strains were able to produce higher amounts of phytohormones, including IAA, GA, and SA. Such activities rendered them as excellent phytostimulants, that can be used as biofertilizers in chromium polluted soils.

Heavy metal tolerant endophytic fungi Aspergillus welwitschiae improves growth, ceasing metal uptake and strengthening antioxidant system in Glycine max L.

In modern agricultural practice, heavy metal (HM) contamination is one of the main abiotic stress threatening sustainable agriculture, crop productivity, and disturb natural soil microbiota. Different reclamation techniques are used to restore the contaminated site; however, they are either costly or unable to remove contaminant when concentration is very low. In such circumstances, bioremediation is used as a novel technique involving microbes for soil restoration. In the current project, Aspergillus welwitschiae(Bk) efficiently endure metal stress (i.e., Cr-VI and As-V in the form of K2Cr2O7 and Na3AsO4) up to 1200 µg/mL and enhanced the production of phytohormones, i.e., 54.83 µg/mL of indole acetic acid (IAA) compared to control 15.56 µg/mL, solubilized inorganic phosphate, and produced stress-related metabolites. The isolate Bk was able to enhance growth of soybean by showing higher root shoot length and fresh/dry weight under stress (p<0.05). Besides, the strain strengthened the antioxidant system of the host increasing enzymatic antioxidants, i.e., catalases (CAT) by 1.58 and 1.11 fold, ascorbic acid oxidase (AAO) by 6.75 and 7.94 fold, peroxidase activity (POD) by 1.12 and 1.37 fold, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) by 1.42 and 1.25 fold at 50 µg/mL of chromate and arsenate. Thus, actively scavenging the reactive oxygen species (ROS) produced results in lower ROS accumulation and high ROS scavenging. On the other hand, the isolates cut down Cr and As uptake by approximately 50% at 50 µg/mL from the medium while bio-transforming it, thereby stabilizing it and assisting the host to resume normal growth, thus avoiding phytotoxicity. It is evident from the current study that A. welwitschiae may potentially be used as a bioremediating agent for reclamation of Cr- and As-contaminated soil.

Phytohormones Producing Acinetobacter bouvetii P1 Mitigates Chromate Stress in Sunflower by Provoking Host Antioxidant Response.

Different physical and chemical techniques are used for the decontamination of Cr+6 contaminated sites. The techniques are expensive, laborious, and time-consuming. However, remediation of Cr+6 by microbes is viable, efficient, and cost-effective. In this context, plant growth-promoting rhizobacteria Acinetobacter bouvetii P1 isolated from the industrial zone was tested for its role in relieving Cr+6 induced oxidative stress in sunflower. At the elevated Cr+6 levels and in the absence of P1, the growth of the sunflower plants was inhibited. In contrast, the selected strain P1 restored the sunflower growth under Cr+6 through plant growth-promoting interactions. Specifically, P1 biotransformed the Cr+6 into a stable and less toxic Cr+3 form, thus avoiding the possibility of phytotoxicity. On the one hand, the P1 strengthened the host antioxidant system by triggering higher production of enzymatic antioxidants, including catalases, ascorbate peroxidase, superoxide dismutase, and peroxidase. Similarly, P1 also promoted higher production of nonenzymatic antioxidants, such as flavonoids, phenolics, proline, and glutathione. Apart from the bioremediation, P1 solubilized phosphate and produced indole acetic acid, gibberellic acid, and salicylic acid. The production of phytohormones not only helped the host plant growth but also mitigated the harsh condition posed by the elevated levels of Cr+6. The findings mentioned above suggest that P1 may serve as an excellent phyto-stimulant and bio-remediator in a heavy metal-contaminated environment.

Pseudocitrobacter anthropi reduces heavy metal uptake and improves phytohormones and antioxidant system in Glycine max L.

Heavy metal contamination due to anthropogenic activities is a great threat to modern humanity. A novel and natural technique of bioremediation using microbes for detoxification of heavy metals while improving plants' growth is the call of the day. In this study, exposing soybean plants to different concentrations (i.e., 10 and 50 ppm) of chromium and arsenic showed a severe reduction in agronomic attributes, higher reactive oxygen species production, and disruption in the antioxidant system. Contrarily, rhizobacterial isolate C18 inoculation not only rescued host growth, but also improved the production of nonenzymatic antioxidants (i.e., flavonoids, phenolic, and proline contents) and enzymatic antioxidants i.e., catalases, ascorbic acid oxidase, peroxidase activity, and 1,1-diphenyl-2-picrylhydrazyl, lower reactive oxygen species accumulation in leaves. Thereby, lowering secondary oxidative stress and subsequent damage. The strain was identified using 16 S rDNA sequencing and was identified as Pseudocitrobacter anthropi. Additionally, the strain can endure metals up to 1200 ppm and efficient in detoxifying the effect of chromium and arsenic by regulating phytohormones (IAA 59.02 µg/mL and GA 101.88 nM/mL) and solubilizing inorganic phosphates, making them excellent phytostimulant, biofertilizers, and heavy metal bio-remediating agent.

Activity guided isolation and mechanistic approach towards analgesic potential of Chenopodium mediated through opioidergic pathway.

The current study is focused towards screening for its phytochemicals, phenolic and flavonoid contents of different species of Chenopodium. The plants were also screened for corroborating the traditional use of medicinal plants locally used for pain by determining the extract and their fractions for the in-vivo analgesic activity by using the modern scientific system. Among chloroform fractions, a high level of total phenolic contents was found in chloroform fraction of Chenopodium ambrosioides (ChAm-Chf) with 57.12±1.02 followed by Chenopodium botrys (ChBt-Chf) with 56.79±0.71. High content of flavonoids was found in chloroform fraction of Chenopodium botrys (ChBt-Chf) extract with 78.35±0.84 followed by Chenopodium ambrosioides (ChAm-Chf) with 75.20±0.81. The crude extract Chenopodium album, Chenopodium botrys and Chenopodium ambrosioides (ChAl-Crd, ChBt-Crd and ChAm-Crd) at 100 and 200 mg/kg, chloroform and ethylacetate fractions (ChAl-Chf, ChBt-Chf, ChAm-Chf, ChAl-Et, ChBt-Et and ChAm-Et) at 75 mg/kg caused significant inhibition (P<0.05, P<0.01, P<0.001, n=8) of the analgesic response induced by acetic acid, formalin and hotplate method. Mechanistically, the naloxone overturns completely the analgesic effects of beta-sitosterol (SN2) while partial reversal was observed by ursolic acid (SN1) indicating other possible mechanisms in association with opioid receptors.

Evaluation of the Hypoglycemic Activity of Morchella conica by Targeting Protein Tyrosine Phosphatase 1B.

Morchella conica (M. conica) Pers. is one of six wild edible mushrooms that are widely used by Asian and European countries for their nutritional value. The present study assessed the anti-diabetic potential of M. conica methanolic extract (100 mg/kg body weight) on streptozotocin (STZ)-induced diabetic mice. STZ was used in a single dose of 65 mg/kg to establish diabetic models. Body weights, water/food intake and fasting blood glucose levels were measured. Histopathological analysis of the pancreas and liver were performed to evaluate STZ-induced tissue injuries. In addition, in vitro assays such as α-amylase and protein tyrosine phosphatase 1B (PTP1B) inhibitory, antiglycation, antioxidant and cytotoxicity were performed. The in vitro study indicated potent PTP1B inhibitory potential of M. conica with an IC50 value of 26.5 µg/ml as compared to the positive control, oleanolic acid (IC50 36.2 µg/ml). In vivo investigation showed a gradual decrease in blood sugar level in M. conica-treated mice (132 mg/dl) at a concentration of 100 mg/kg as compared to diabetic mice (346 mg/dl). The extract positively improved liver and kidney damages as were shown by their serum glutamic pyruvic transaminase, serum glutamic oxaloacetate, alkaline phosphatase, serum creatinine and urea levels. Histopathological analysis revealed slight liver and pancreas improvement of mice treated with extract. Cytotoxicity assays displayed lower IC50 values. Based on the present results of the study, it may be inferred that M. conica are rich in bioactive compounds responsible for antidiabetic activity and this mushroom may be a potential source of antidiabetic drug. However, further studies are required in terms of isolation of bioactive compounds to validate the observed results.

Phytohormones producing rhizobacterium alleviates chromium toxicity in Helianthus annuus L. by reducing chromate uptake and strengthening antioxidant system.

Contamination of agricultural land with heavy metal is a serious biological and environmental issue. Such threat can be challenged by exploring the plant symbiotic microbes that can improve plant growth through phyto-hormones secretion and chromate chelation. In the current study, chromate resistant rhizospheric Staphylococcus arlettae strain MT4 was isolated from the rhizosphere of Malvestrum tricuspadatum L. The strain showed potential to secrete phytohormones and plant growth promoting secondary metabolites under induced chromate stress, making it a best suitable candidate in chromate stress alleviation. Moreover, the rhizobacterium MT4 significantly promoted the net assimilation and relative growth rate of sunflower grown in the presence of chromate (100 ppm). Chromate stress alleviation strategy of MT4 strain was three-fold. MT4 alleviated chromate stress and promoted the sunflower growth by suppressing the chromate intake by the host, modulating phytohormones and strengthening of the host's antioxidant system. The improved antioxidant system was confirmed by noticing lower ROS accumulation and improved ROS scavenging, lower peroxidase activity and higher accumulation of phenols and flavonoids.

Bioremediation of hexavalent chromium by endophytic fungi; safe and improved production of Lactuca sativa L.

One of the main problems of the industrialized world is the accumulation of chromium (Cr) in soil, which is a serious threat to the crops. Complete removal of Cr from the contaminated soils poses a great challenge. However, this issue can be minimised by using plant growth promoting microbes as a bioremediation tool. In the present study, healthy plants established near the University campus in Mardan were selected for the isolation of Cr resistant endophytes. From the designated plants, 114 species of endophytic fungi were isolated. Among the 114 isolated strains, 4 strains have induced resistance in L. sativa against Cr. The strains were identified as Aspergillus fumigatus, Rhizopus sp., Penicillium radicum and Fusarium proliferatum based on ITS region (18 S rDNA) homology. The isolates have removed Cr from soil and culture media as well as bio-transformed it from highly toxic hexavalent to least toxic trivalent form, thus helped the Cr stressed L. sativa to restore its normal growth. The Rhizopus Sp. CUC23 has mainly accrued Cr and detoxified intracellularly, whereas A. fumigatus ML43 and P. radicum PL17 has detoxified up to 95% of Cr extracellularly. From the results, it is concluded that the selected endophytic strains might be used as biofertilizer for healthy and safe crop production in Cr contaminated soils.

Home area network for optimizing telehealth services--empirical simulation analysis.

Telehealth applications such as Video-over-IP and remote sensor monitoring are rapidly growing in utilisation and it has now expanded to the patient's homes. These Telehealth applications are, however highly delay sensitive and require high quality (and bandwidth priority) in order to provide satisfactory performances. However, at the patient's home area network (HAN) environment, typically there is no Internet traffic management system which highly affects the quality of these applications. As HAN expands its capacity by adding new devices in its network, the need for a network management system become urgent and necessary. In this study, we propose an infrastructure based method to improve Telehealth application quality by managing the quality and distribution of the Internet traffic among the connected devices in a HAN environment. We setup a HAN environment using existing devices readily available at home and tested the setting with typical Telehealth application needs that includes Video-over-IP, VoIP, data and other multimedia traffic. Our simulation results showed that our method is capable of providing better services. Our method indicated that it can provide ~11% lesser packet-loss under 12Mbps background traffic, while increasing 10% of the CPU load for Traffic management.