A Case for Below-Ground Dispersal? Insights into the Biology, Ecology and Conservation of Blind Cave Spiders in the Genus Troglodiplura (Mygalomorphae: Anamidae).

Previously described from only fragments of exoskeleton and juvenile specimens, the cave spider genus Troglodiplura (Araneae: Anamidae), endemic to the Nullarbor Plain, is the only troglomorphic member of the infraorder Mygalomorphae recorded from Australia. We investigated the distribution of Troglodiplura in South Australia, collecting and observing the first (intact) mature specimens, widening the number of caves it has been recorded in, and documenting threats to conservation. Phylogenetic analyses support the placement of Troglodiplura as an independent lineage within the subfamily Anaminae (the 'Troglodiplura group') and provide unequivocal evidence that populations from apparently isolated cave systems are conspecifics of T. beirutpakbarai Harvey & Rix, 2020, with extremely low or negligible inter-population mitochondrial divergences. This is intriguing evidence for recent or contemporary subterranean dispersal of these large, troglomorphic spiders. Observations of adults and juvenile spiders taken in the natural cave environment, and supported by observations in captivity, revealed the use of crevices within caves as shelters, but no evidence of silk use for burrow construction, contrasting with the typical burrowing behaviours seen in other Anamidae. We identify a range of threats posed to the species and to the fragile cave ecosystem, and provide recommendations for further research to better define the distribution of vulnerable taxa within caves and identify actions needed to protect them.

Characteristics of binding of insulin-like growth factor (IGF)-I and IGF-II analogues to the type 1 IGF receptor determined by BIAcore analysis.

Insulin-like growth factor (IGF) binding to the type 1 IGF receptor (IGF1R) elicits mitogenic effects, promotion of differentiation and protection from apoptosis. This study has systematically measured IGF1R binding affinities of IGF-I, IGF-II and 14 IGF analogues to a recombinant high-affinity form of the IGF1R using BIAcore technology. The analogues assessed could be divided into two groups: (a) those designed to investigate binding of IGF-binding protein, which exhibited IGF1R-binding affinities similar to those of IGF-I or IGF-II; (b) those generated to probe IGF1R interactions with greatly reduced IGF1R-binding affinities. The relative binding affinities of IGF-I analogues and IGF-I for the IGF1R determined by BIAcore analysis agreed closely with existing data from receptor-binding assays using cells or tissue membranes, demonstrating that BIAcore technology is a powerful tool for measuring affinities of IGFs for IGF1R. In parallel studies, IGF1R-binding affinities were related to ability to protect against serum withdrawal-induced apoptosis in three different assays including Hoechst 33258 staining, cell survival, and DNA fragmentation assays using the rat pheochromocytoma cell line, PC12. In this model system, IGF-I and IGF-II at low nanomolar concentrations are able to prevent apoptosis completely. We conclude that ability to protect against apoptosis is directly related to ability to bind the IGF1R.