ABSTRACTOne of the primary purposes of pine cones is the protection and distant dispersal of pine seeds. Pine cones open and release their embedded seeds on dry and windy days for long-distance dispersal. In this study, how the pine seeds attach to/detach from the pine cone scale for efficient seed dispersal was experimentally investigated by using an X-ray micro-imaging technique. The cone and seeds adhere to each other in the presence of water, which could be explained by the surface tension and the contact angle hysteresis. Otherwise, without water, the waterproof seed wing surface permits rapid drying for detach and dispersion. On the other hand, during wildfires, pine cones open their seed racks and detach the pine seeds from pine cones for rapid seed dispersal. Due to these structural advantages, pine seeds are released safely and efficiently in normal conditions. These advantageous structures could be mimicked in practical applications.

ABSTRACTIron is an essential micro-element for plant growth. In the calcareous soils of Lebanon, immobilization of iron can lead to chlorosis and reduce the yields of agricultural production. Iron fertilization is therefore crucial to ensure good plant growth. The objective of this work was to compare the efficiency of the iron chelate HBED-Fe to that of EDDHA-Fe, on tomato (Solanum lycopersicum L.) and cucumber crops (Cucumis sativus L.). Five modules were studied in two separate greenhouses: one control, one module with fertilization by EDDHA-Fe and three modules with different applications of HBED-Fe. Chlorophyll and Fe contents in leaves were analyzed at different stages of the plants' cycle. Cucumber crops treated with HBED-Fe showed 19.2% higher chlorophyll content than the ones treated with EDDHA-Fe. Tomato crops presented 11.2% higher chlorophyll content when treated with HBED-Fe. For cucumbers, HBED-Fe should be applied in three applications separated by 25 days. For tomatoes, HBED-Fe should be applied in two applications separated by a month. The use of the HBED9% iron chelate was proved to be more effective than that of EDDHA6% because more efficiency was achieved with 40% less application rate. Multiple applications were also more effective than single applications.

ABSTRACTBioindicators are living organisms such as plants, planktons, animals, and microbes, which are utilized to screen the health of the natural ecosystem in the environment. They are used for assessing environmental health and biogeographic changes taking place in the environment. Each organic entity inside a biological system provides an indication regarding the health of its surroundings such as plankton responding rapidly to changes taking place in the surrounding environment and serving as an important biomarker for assessing the quality of water as well as an indicator of water pollution. Even the health of aquatic flora is best reflected by plankton, which acts as an early warning signal. In this review we have tried to explain the concept behind Bioindicators and plankton, with particular emphasis on their potential to be used as Bioindicators for water quality assessment and outcomes relating to this.

Salmonella is one of the most frequently isolated foodborne pathogens. It is a major worldwide public health concern, accounting for 93.8 million foodborne illnesses and 155,000 deaths per year. To date, over 2500 Salmonella serotypes have been identified and more than half of them belong to Salmonella enterica subsp. enterica, which accounts for the majority of Salmonella infections in humans. Salmonella infections that involve invasive serotypes are often life threatening, necessitating appropriate and effective antibiotic therapy. The emergence of multi-drug-resistant (MDR) Salmonella serotypes is having a great impact on the efficacy of antibiotic treatment, and an increasing prevalence of MDR strains may lead to an increase in mortality rates of Salmonella infections. Epidemiological studies indicate that MDR Salmonella serotypes are more virulent than susceptible strains, as reflected by increased severity and more prolonged disease in patients infected by MDR strains. Preventive measures have been proposed to eliminate the spread of Salmonella infection. While the maintenance of effective food hygiene and water sanitation remain the cornerstones, additional measures such as restriction of indiscriminate use of antibiotics in food animals are important. This review provides an overview of Salmonella infection, and discusses the nomenclature, pathogenesis, clinical manifestations, epidemiology and antibiotic resistance of Salmonella.

Two edible seaweeds, Sargassum polycystum and Sargassum wightii, were investigated for their antidiabetic potential using in vitro enzyme inhibitory assays. Among the various extracts, petroleum ether and ethyl acetate extracts of S. wightii showed significant inhibitory effects against α-amylase (IC50 378.3 µg/ml) and α-glucosidase (IC50 314.8 µg/ml). Methanol extract of S. wightii showed the highest inhibition against dipeptidyl peptidase-IV (DPP-IV) (IC50 38.27 µg/ml) and moderate antioxidant activity was observed in acetone extract of S. wightii (44%). Similarly, ethyl acetate extract of S. polycystum showed the highest inhibition against α-amylase (IC50 438.5 µg/ml) and methanol extract of S. polycystum showed maximum inhibition against α-glucosidase (IC50 289.7 µg/ml) and DPP-IV (36.94 µg/ml). The antioxidant activity was poor (22%). The extracts were investigated for in vitro cytotoxicity, DNA fragmentation in macrophages and haemolytic activity against erythrocytes, but no notable toxicity was observed with any of the tested extracts. Gas chromatography–mass spectrometry revealed the presence of the antidiabetic compound fucosterol and other major bioactive compounds, giving an insight into the antidiabetic and antioxidant properties of these algae. This study reveals the possible mechanisms of antidiabetic action in vitro, and these two seaweeds may also have an antidiabetic action in vivo.

The present study was undertaken to explore the comparative phytochemical analysis and immunomodulating activities of various successively extracted leaf extracts of Stevia rebaudiana (Bertoni) in albino rats. Phytochemical screening conducted on various organic leaf extracts of S. rebaudiana revealed the presence of several biologically active molecules that include sterols, saponins, alkaloids, glycosides, phenols, tannins, flavonoids and resins. The immunomodulatory activities were determined by neutrophil adhesion test, haemagglutination antibody (HA) titre delayed type hypersensitivity (DTH) response and phagocytic activity. The response produced by oral administration of ethanolic and aqueous leaf extracts showed a significant increase in neutrophil adhesion and DTH response. The augmentation of humoral immune response to sheep red blood cells by ethanolic and aqueous extracts at 300–500 mg kg–1 was higher than when an extract dose of 200 mg kg–1 was used, as shown by a dose-related increase in antibody titres in experimental rats. This study demonstrates potent immunomodulatory activities and therapeutic potential of phytochemical compounds extracted from S. rebaudiana leaf to combat against immunological disorders.

Locomotion at micro and nano scales is a challenge and has drawn attention for over six decades. Inspired by nature, studies have mimicked nanoswimming organisms, which use rotating or beating flagella for locomotion. This mode of propulsion, also known as flagellar propulsion, has been explored extensively in the literature. However, chemical and magnetic methods have gained interest in the last decade owing to advantages including high thrust force and wireless control. The review summarizes chronologically the various propulsion mechanisms for moving a nanoswimmer using chemical fuel, magnetic fields, ultrasonic pulses and thrust force generated by bacteria in the presence of external stimuli including laser light, and thermal and chemical gradients.

The antimicrobial effects of silver nanocomposite particles (Ag-ZnO NC) on microorganisms, the antimicrobial mechanism and applications in medical devices are not yet clear. Stable Ag-ZnO NC were prepared and their morphological sizes and shapes were characterized by scanning electron microscopy. The effect of Ag-ZnO NC was tested on Bacillus thuringiensis, Escherichia coli and Pseudomonas aeruginosa in antibacterial tests including growth kinetics, antimicrobial susceptibility (disc diffusion) and minimal inhibitory concentration (MIC). Different concentrations of nanocomposites (i.e. 10, 20, 50,100, and 200 μg) showed concentration-dependant efficacy on all three tested microorganisms. E. coli was fairly sensitive in 200 μg of NC, forming a ∼15 mm inhibition zone; followed by B. thuringiensis, having ∼9 mm of inhibition zone, while P. aeruginosa, a pathogenic bacterium, showed negligible inhibition zone with Ag-ZnO NC. Growth of E. coli under Ag-ZnO NC treatment was significantly delayed with an extended lag phase of 2 hrs and 30 mins. Scanning electron microscopy confirmed the bacteriostatic effect of Ag-ZnO NC, which was manifested in cell division arrest with significant cell elongations compared to the control. The free radical generation effect of Ag-ZnO NC was tested against all these organisms. The results suggest that Ag-ZnO NC can be used effectively against microbial growth. This may be of use in diverse medical devices for antimicrobial control and can be a proper substitute for antibiotics in curing human health.

Hairy root cultures (HRCs) of Boerhaavia diffusa L., an ethno-medicinally important herb, were established via explant co-cultivation with Agrobacterium rhizogenes. Several key factors influencing transformation efficiency were optimized. Rhizoclones showing prolific growth were maintained through successive subcultures in solidified Murashige & Skoog's medium without growth regulators (MS0) under diffused illumination. PCR analysis of the rhizoclones demonstrated positive amplification of rolB and rolC genes of pRi TL-DNA. Reverse transcription-PCR (RT-PCR) and opine assay revealed the presence and expression of the pRi TR-DNA borne ags gene. The methanol and dichloromethane (M:DM) extracts of hairy roots (HRs) and natural roots (NRs) were screened against a wide range of bacterial pathogens causing human urinary tract infections (UTIs). The MIC and MBC values of HRs were markedly lower when compared to NRs against microorganisms causing UTIs. Extracts of HRs were more effective than those of NRs not only against wild type strains but also, and more importantly, against multi-drug resistant strains. Establishment of fast-proliferating renewable HRCs of B. diffusa would provide a direct source of anti-microbial phytocompounds against several pathogenic bacteria, including resistant strains, causing UTIs.