Female behaviour prior to additional sperm receipt in the hermaphroditic pond snail Lymnaea stagnalis

In many species, sexual resistance by females can fluctuate depending on different physiological and/or ecological conditions. Based on theory, we decided to test whether the simultaneous hermaphrodite Lymnaea stagnalis becomes more reluctant to mate in the female role after receipt of an ejaculate. We aimed to test whether receipt of an ejaculate affects the expression of recipient behaviours, and whether this can have a potential effect on the outcome of mating interactions. We found that the expression of Crawl-out and Biting behaviours increased significantly in recently inseminated snails. Our data also indicated that an increase in expression of these latter behaviours can have direct effects on the outcome of the mating interactions. These findings suggest that under the influence of recent insemination, this hermaphroditic snail is more reluctant to accept another mating in the female role and may try to actively discourage the mounting snail (sperm donor). Hence, despite the fact that these simultaneous hermaphrodites express both sexual functions, there can still be variation in motivation to mate in either role.     

Wound healing applications of biogenic colloidal silver and gold nanoparticles: recent trends and future prospects

Applied Microbiology and Biotechnology - Nanotechnology has emerged as a prominent scientific discipline in the technological revolution of this millennium. The scientific community has focused on...     

The effect of slow-growth strategy on a production of Petunia × hybrida Vilm. microcuttings

Petunia × hybrida Vilm. is a fast-growing ornamental plant that was cultured under varying storage conditions to address seasonal fluctuations in microcutting demand. The effects of storage period (16 to 32 wk), temperature (15 to 23°C), low and high light intensity, sucrose (1 to 5% w/v), and mannitol (0 to 4% w/v) in factorial arrangements were analyzed. Stored and non-stored shoots were compared for microcutting production, harvested twice at 3-wk intervals, and were subsequently transferred to the greenhouse for 17 d. Nearly all plants from 16-wk storage survived well at all treatment conditions and the quality and quantity of microcuttings were enhanced from shoots stored at 15°C and 3% (w/v) sucrose, without mannitol for all storage periods. Another experiment tested 11- to 25-wk storage period with Petunia hybrida ‘Ragtime’ and ‘Suncatcher’ at 12°C and low light intensity. Repeated cycles of microcutting at 2-wk intervals were extended with ex vitro rooting in the greenhouse for 15 d. More and better quality microcuttings were obtained from the second and third cutting cycles than from the first or fourth cycles. By reducing temperature and light intensity, Petunia hybrida was successfully stored for 32 wk (without mannitol). A seasonal schedule with a short production window, followed by cutting large numbers of high-quality shoot-tips, could be affected and efficiently managed through storage. The value of stored shoots was enhanced by extending the number of times a shoot could be cut over repeated cutting cycles with a gain in microcutting quality.

     

Extracellular identification of a processed type II ComR/ComS pheromone of Streptococcus mutans

The competence-stimulating peptide (CSP) and the sigX-inducing peptide (XIP) are known to induce Streptococcus mutans competence for genetic transformation. For both pheromones, direct identification of the native peptides has not been accomplished. The fact that extracellular XIP activity was recently observed in a chemically defined medium devoid of peptides, as mentioned in an accompanying paper (K. Desai, L. Mashburn-Warren, M. J. Federle, and D. A. Morrison, J. Bacteriol. 194:3774-3780, 2012), provided ideal conditions for native XIP identification. To search for the XIP identity, culture supernatants were filtered to select for peptides of less than 3 kDa, followed by C(18) extraction. One peptide, not detected in the supernatant of a comS deletion mutant, was identified by tandem mass spectrometry (MS/MS) fragmentation as identical to the ComS C-terminal sequence GLDWWSL. ComS processing did not require Eep, a peptidase involved in processing or import of bacterial small hydrophobic peptides, since eep deletion had no inhibitory effect on XIP production or on synthetic XIP response. We investigated whether extracellular CSP was also produced. A reporter assay for CSP activity detection, as well as MS analysis of supernatants, revealed that CSP was not present at detectable levels. In addition, a mutant with deletion of the CSP-encoding gene comC produced endogenous XIP levels similar to those of a nondeletion mutant. The results indicate that XIP pheromone production is a natural phenomenon that may occur in the absence of natural CSP pheromone activity and that the heptapeptide GLDWWSL is an extracellular processed form of ComS, possibly the active XIP pheromone. This is the first report of direct identification of a ComR/ComS pheromone.     

A strategy for mitigating avian colibacillosis disease using plant growth promoting rhizobacteria and green synthesized zinc oxide nanoparticles

Avian colibacillosis caused by the zoonotic pathogen Escherichia coli is a common bacterial infection that causes major losses in the poultry sector. Extracts of different medicinal plants and antibiotics have been used against poultry bacterial pathogens. However, overuse of antibiotics and extracts against pathogenic strains leads to the proliferation of multi-drug resistant bacteria. Due to their environmentally friendly nature, nanotechnology and beneficial bacterial strains can be used as effective strategies against poultry infections. Green synthesis of zinc oxide nanoparticles (ZnO-NPs) from Eucalyptus globulus leaves was carried out in this study. Their characterization was done by UV–vis spectroscopy, X-ray diffraction (XRD), and Fourier transmission infrared spectroscopy (FT-IR) which confirmed their synthesis, structure, and size. In vitro, antimicrobial activities of plant leaf extract, ZnO-NPs, and plant growth-promoting rhizobacteria (PGPR) were checked against E. coli using well diffusion as well as disc diffusion method. Results proved that the antimicrobial activity of ZnO-NPs and PGPR strains was more enhanced when compared to eucalyptus leaf extract at 36 h. The maximum relative inhibition shown by ZnO-NPs, PGPR strains and eucalyptus leaf extracts was 88%, 67% and 58%, respectively. The effectiveness of ZnO-NPs was also increased with an increase in particle dose and treatment time. The 90 mg/ml of ZnO-NPs was more effective. PGPR strains from all over the tested strains, Pseudomonas sp. (HY8N) exhibited a strong antagonism against the E. coli strain as compared to other PGPR strains used in this study. However, combined application of PGPR (Pseudomonas sp. (HY8N)) and ZnO-NPs augment antagonistic effects and showed maximum 69% antagonism. The study intends to investigate the binding affinity of ZnO-NPs with the suitable receptor of the bacterial pathogen by in silico methods. The binding site conformations showed that the ligand ZnO binds with conserved binding site of penicillin-binding protein 6 (PBP 6) receptor. According to the interactions, ZnO-NPs form the same interaction pattern with respect to other reported ligands, hence it can play a significant role in the inhibition of PBP 6. This research also found that combining ZnO-NPs with Pseudomonas sp. (HY8N) was a novel and effective technique for treating pathogenic bacteria, including multidrug-resistant bacteria.     

Heparan sulfate/heparin oligosaccharides protect stromal cell-derived factor-1 (SDF-1)/CXCL12 against proteolysis induced by CD26/dipeptidyl peptidase IV

Stromal cell-derived factor-1 (SDF-1) is a CXC chemokine that is constitutively expressed in most tissues and displayed on the cell surface in association with heparan sulfate (HS). Its numerous biological effects are mediated by a specific G protein-coupled receptor, CXCR4. A number of cells inactivate SDF-1 by specific processing of the N-terminal domain of the chemokine. In particular, CD26/dipeptidyl peptidase IV (DPP IV), a serine protease that co-distributes with CXCR4 at the cell surface, mediates the selective removal of the N-terminal dipeptide of SDF-1. We report here that heparin and HS specifically prevent the processing of SDF-1 by DPP IV expressed by Caco-2 cells. The level of processing increases with the level of differentiation of these cells, which correlates with an increase of DPP IV activity. A mutant SDF-1 that does not interact with HS is readily cleaved by DPP IV, a process that is not inhibited by HS, demonstrating that a productive interaction between HS and SDF-1 is required for the protection to take place. Moreover, we found that protection depends on the degree of polymerization of the HS sulfated S-domains. Finally a structural model of SDF-1, in complex with HS oligosaccharides of defined length, rationalizes the experimental data. The mechanisms by which HS regulates SDF-1 may thus include, in addition to its ability to locally concentrate the chemokine at the cell surface, a control of selective protease cleavage events that directly affect the chemokine activity.     

Ethnopharmacological Survey of Plants Used for the Treatment of Stomach,Diabetes, and Ophthalmic Diseases in Sudhan Gali,Kashmir , Pakistan

The present paper represents the ethnopharmacological survey of Sudhan Gali, Kashmir, Pakistan. The study revealed that 12 plant species belonging to 11 families were used for the treatment of stomach, diabetes and ophthalmic diseases by the local people in Sudhan Gali. Achillea millefolium , Aconitum heterophyllum, Berberis lycium, Polygonum amplexicaule, Mentha longifolia, Paeonia emodi, Plantago lanceolata were locally used for stomach related problems treatment; Berberis lycium, Skimmia lareola, Solanum dulcamara for diabetes and Geranium wallichianum, Artemisia vulgaris, Solanum dulcamara, and Corydalis crassifolia used for the treatment of ophthalmic diseases. Two species Berberis lycium and Solanum dulcamara have multipurpose value. Former is used to treat stomach as well as diabetes while latter is used to treat not only to diabetes but also ophthalmic diseases. According to IUCN categories , out of these 12 plant species collected and marketed, Polygonum amplexicaule and Paeonia emodi are endangered, Aconitum heterophyllum; Berberis lycium species are vulnerable while Plantago lanceolata and Skimmia lareola species are rare.The availability of these medicinal plants has decreased during the past 20 years and these are facing a drastic biotic pressure due to their extensive usage and non-scientific methods of collection. It is quite evident that these valuable native medicinal plants species are going to decline in number and ultimately will become extinct if no timely proper conservation strategies are adopted.     

Environmental Health Indicators in New Zealand: Drinking Water—A Case Study

This study examines and quantifies the linkages between population health, environmental risks, and its determinants for drinking water in New Zealand using routinely collected data. It was conducted as part of the national environmental health indicators project in New Zealand. The project is based on the World Health Organization’s (WHO) “Environmental and Health Information System” program. Drinking water quality indicators based on the Driving force–Pressure–State–Exposure–Effect–Action (DPSEEA) framework as part of this program were analyzed to validate the model by quantifying the linkages between the indicators. The results of the model suggested over the study period, the state (drinking water quality) and exposure (water access) indicators are significant independent predictors of the effect indicator (waterborne disease rate). This study suggests that routinely collected data can be structured using the DPSEEA framework and tested quantitatively using standard Poisson regression models, thus, illustrating that the model can be used routinely to provide a basis for consideration of the costs and benefits of any interventions to reduce the burden of waterborne disease. Data quality issues need to be considered if such routinely collected data linkages are to be performed for policy purposes. The online version of this article (doi:) contains electronic supplementary material, which is available to authorized users. Supplemental histograms are available in the online appendix.     

Cytokines and growth factors cross-link heparan sulfate

The glycosaminoglycan heparan sulfate (HS), present at the surface of most cells and ubiquitous in extracellular matrix, binds many soluble extracellular signalling molecules such as chemokines and growth factors, and regulates their transport and effector functions. It is, however, unknown whether upon binding HS these proteins can affect the long-range structure of HS. To test this idea, we interrogated a supramolecular model system, in which HS chains grafted to streptavidin-functionalized oligoethylene glycol monolayers or supported lipid bilayers mimic the HS-rich pericellular or extracellular matrix, with the biophysical techniques quartz crystal microbalance (QCM-D) and fluorescence recovery after photobleaching (FRAP). We were able to control and characterize the supramolecular presentation of HS chains—their local density, orientation, conformation and lateral mobility—and their interaction with proteins. The chemokine CXCL12α (or SDF-1α) rigidified the HS film, and this effect was due to protein-mediated cross-linking of HS chains. Complementary measurements with CXCL12α mutants and the CXCL12γ isoform provided insight into the molecular mechanism underlying cross-linking. Fibroblast growth factor 2 (FGF-2), which has three HS binding sites, was also found to cross-link HS, but FGF-9, which has just one binding site, did not. Based on these data, we propose that the ability to cross-link HS is a generic feature of many cytokines and growth factors, which depends on the architecture of their HS binding sites. The ability to change matrix organization and physico-chemical properties (e.g. permeability and rigidification) implies that the functions of cytokines and growth factors may not simply be confined to the activation of cognate cellular receptors.