No abstract

The beta-turn, which has also been referred to as the beta-bend, beta-loop or reverse turn, has been implicated as an important site for molecular recognition in many biologically active peptides and in globular proteins. This small secondary structure therefore makes an attractive target for mimicry by a conformational constraint, because a peptide which is constrained in a biologically active conformation can display a number of advantages over the parent substrate. The less peptide-like such a constraint is, the more potential there is to maximize these advantages. A decade has passed since the first (and highly successful) attempt to mimic the beta-turn with a nonpeptide conformational constraint was disclosed by Freidinger et al. (1980). Since this report, rapidly growing interest in the field of nonpeptide beta-turn mimics has seen a variety of experimental approaches and a mixed bag of results. It is attempted in this review, not only to summarize and critically analyse these approaches, but also to touch on the complexities associated with the conformational mimicry of such a diverse structure as the beta-turn.

Nemopteridae are a charismatic family of lacewings characterised by uniquely extended hind wings.They are an ancient widespread group in the drier regions of the world. The family comprises two subfamilies, Crocinae (thread-wings) and Nemopterinae (spoon-and ribbon-wings). The present distribution of the family has been largely influenced by the vicariant events of plate tectonics, resulting in relict populations in some parts of the world and extensive evolutionary radiations in others, particularly southern Africa where the vast majority of the species are endemic to the Western and Northern Cape Provinces of South Africa. This study aimed to establish the validity of the 11 currently recognised genera and infer their biogeographic history using molecular sequence data from four gene regions. The hypothesis that the Cape nemopterines co-evolved with certain taxa in the Cape Floristic Region was also tested.Phylogenetic analysis supports seven of the 11 currently recognised genera. The crown age of the Nemopterinae is estimated to be at ca. 145.6 Mya, indicating that the group has been present since the late Jurassic. Most of the genera appear to have diversified during the middle Eocene and into the middle Miocene (ca. 44 -11 Mya) with recent rapid radiation of several of the genera occurring during the late Miocene (ca. 6 -4.5 Mya). While these data support an initial radiation with the Rushioideae (Aizoaceae) it is recommended that further study including observations and gut content be carried out. [238]

The Southern African Lepidoptera Conservation Assessment (SALCA) was a collaborative venture between the Lepidopterists’ Society of Africa (LepSoc Africa), the Brenton Blue Trust (BBT) and the South African National Biodiversity Institute (SANBI), and formed part of the National Biodiversity Assessment (NBA). SALCA was founded on the importance of Lepidoptera both ecologically and as biodiversity indicators and the proven expertise of the participants during the Southern African Butterfly Conservation Assessment (SABCA). The main outcomes of the SALCA project are presented and discussed here.The SALCA tool, a custom-designed interactive distribution database, enabled high quality data to be derived so that accurate conservation assessments could be produced in accordance with IUCN methodology. The Red Lists of SALCA and SABCA facilitated the first opportunity to calculate the Red List Index (RLI) for South African butterflies during the period from 2012–2018. Other metrics required for the NBA included protection level and threats analyses. A further outcome was the critical habitat mapping for butterflies, which formed part of a screening tool implemented by SANBI, to ensure that land use changes did not cause any further loss of butterfly biodiversity.A comprehensive distribution database was developed for South African moths, enabling data to be analysed so that moth species potentially threatened could be short-listed for further investigation.Geographical hotspots and ecosystems (vegetation types) containing butterflies of conservation concern are highlighted. The societal, economic and human wellbeing benefits of conserving Lepidoptera are identified. Responses by LepSoc Africa to the increasing pressures on South African Lepidoptera biodiversity, are also reported on and discussed. The significant outcomes of SABCA and SALCA are benchmarked against a well-known European butterfly atlasing and conservation assessment project.The 165 SALCA Red Lists and conservation assessments are presented at the end of this publication.

The /3-turn is a common secondary structure in biologically active pcptides and globular proteins, where it is widely thought to serve as a molecular recognition site for many biological processes. Although the primary b-turn recognition requirements are thought to be straightforward, relating mainly to the relative positions of the peptide sidechains, current classifications of p-turns are complex and are based solely upon the very variable geometry of the peptide backbone. We demonstrate here that B-turns can be described in terms of a single dihedral angle, which we have called /I, which provides a complete description of the spatial relationship between the entry and exit peptide bonds as well as the relative orientations of the intervening sidechains for any B-turn. This description should prove particularly useful in the development and application of novel peptide mimetic drugs, compounds for which a classification based on a peptide backbone geometry may be entirely irrelevant.