A Combined Molecular Cloning and Mass Spectrometric Method to Identify, Characterize, and Design Frenatin Peptides from the Skin Secretion of Litoria infrafrenata

Amphibian skin secretions are unique sources of bioactive molecules, particularly bioactive peptides. In this study, the skin secretion of the white-lipped tree frog (Litoria infrafrenata) was obtained to identify peptides with putative therapeutic potential. By utilizing skin secretion-derived mRNA, a cDNA library was constructed, a frenatin gene was cloned and its encoded peptides were deduced and confirmed using RP-HPLC, MALDI-TOF and MS/MS. The deduced peptides were identified as frenatin 4.1 (GFLEKLKTGAKDFASAFVNSIKGT) and a post-translationally modified peptide, frenatin 4.2 (GFLEKLKTGAKDFASAFVNSIK.NH2). Antimicrobial activity of the peptides was assessed by determining their minimal inhibitory concentrations (MICs) using standard model microorganisms. Through studying structure–activity relationships, analogues of the two peptides were designed, resulting in synthesis of frenatin 4.1a (GFLEKLKKGAKDFASALVNSIKGT) and frenatin 4.2a (GFLLKLKLGAKLFASAFVNSIK.NH2). Both analogues exhibited improved antimicrobial activities, especially frenatin 4.2a, which displayed significant enhancement of broad spectrum antimicrobial efficiency. The peptide modifications applied in this study, may provide new ideas for the generation of leads for the design of antimicrobial peptides with therapeutic applications.

Highlights from Faraday Discussion: Designing New Heterogeneous Catalysts, London, UK, April 2016

The Faraday Discussion on the design of new heterogeneous catalysts took place from 4-6 April 2016 in London, United Kingdom. It brought together world leading scientists actively involved in the synthesis, characterisation, modelling and testing of solid catalysts, attracting more than one hundred delegates from a broad spectrum of backgrounds and experience levels-academic and industrial researchers, experimentalists and theoreticians, and students. The meeting was a reflection of how big of an impact the ability to control and design catalysts with specific properties for particular processes can potentially have on the chemical industry, environment, economy and society as a whole. In the following, we give an overview of the topics covered during this meeting and briefly highlight the content of each presentation.

Footbridge system identification using wireless inertial measurement units for force and response measurements

With the main focus on safety, design of structures for vibration serviceability is often overlooked or mismanaged, resulting in some high profile structures failing publicly to perform adequately under human dynamic loading due to walking, running or jumping. A standard tool to inform better design, prove fitness for purpose before entering service and design retrofits is modal testing, a procedure that typically involves acceleration measurements using an array of wired sensors and force generation using a mechanical shaker. A critical but often overlooked aspect is using input (force) to output (response) relationships to enable estimation of modal mass, which is a key parameter directly controlling vibration levels in service.

This paper describes the use of wireless inertial measurement units (IMUs), designed for biomechanics motion capture applications, for the modal testing of a 109 m footbridge. IMUs were first used for an output-only vibration survey to identify mode frequencies, shapes and damping ratios, then for simultaneous measurement of body accelerations of a human subject jumping to excite specific vibrations modes and build up bridge deck accelerations at the jumping location. Using the mode shapes and the vertical acceleration data from a suitable body landmark scaled by body mass, thus providing jumping force data, it was possible to create frequency response functions and estimate modal masses.

The modal mass estimates for this bridge were checked against estimates obtained using an instrumented hammer and known mass distributions, showing consistency among the experimental estimates. Finally, the method was used in an applied research application on a short span footbridge where the benefits of logistical and operational simplicity afforded by the highly portable and easy to use IMUs proved extremely useful for an efficient evaluation of vibration serviceability, including estimation of modal masses.

Planning for the Unseen and Unheard: the child with ASD

“Children are a kind of indicator species.
If we can build a successful city for children,
we will have a successful city for all people.”

Enrique Peñalosa (former mayor of Bogotá)

Should society be judged by how they treat their weakest members, the concept of the Child Friendly City offers more than ample scope for critiquing the genuine health and inclusivity of our urban environments. If we accept childhood as a crucial human development phase that demands inclusive and welcoming places for play, exploration and growth, many cities today are becoming increasingly barren habitats, arguably full of nothing but empty childhoods. (Raven-Ellison 2015) With children today less able to roam and explore our streets than those of yesteryear, (Bird 2007) the situation is now developing where our young are becoming increasingly socially and spatially excluded from our supposedly shared Built Environment. That progressively restrictive urban realm is particularly pronounced for those with Autism Spectrum Disorder, for whom our cities can be disorientating, difficult and even frightening places.

As a profession we have a responsibility to provide inclusive built environments that do not preclude the presence of the most vulnerable in society, among them those with ASD. Accordingly this paper seeks to introduce emerging research into the current challenges facing these young urban stakeholders before discussing how planning processes and design interventions might make our cities more accessible to those with ASD.

References:

Bird, W. (2007) Natural Thinking, Sandy, Bedfordshire: RSPB.

Raven-Ellison, D. (2015) “London’s Empty Childhoods” in London Essays – Green Spaces, Issue 3 – found at: http://essays.centreforlondon.org/issues/green/londons-empty-childhoods/ accessed 9th May 2016.