Sequence of Spider Aciniform and Piriform Silks

2010

Orb-weaving spider silk fibers are assembled from very large, highly repetitive proteins. The repeated segments contain, in turn, short, simple, and repetitive amino acid motifs that account for the physical and mechanical properties of the assembled fiber. Of the six orb-weaver silk fibroins, the piriform silk that makes the attachment discs, which lashes the joints of the web and attaches dragline silk to surfaces, has not been previously characterized. Piriform silk protein cDNAs were isolated from phage libraries of three species: A. trifasciata, N. claVipes, and N. cruentata. The deduced amino acid sequences from these genes revealed two new repetitive motifs: an alternating proline motif, where every other amino acid is proline, and a glutamine-rich motif of 6-8 amino acids. Similar to other spider silk proteins, the repeated segments are large (>200 amino acids) and highly homogenized within a species. There is also substantial sequence similarity across the genes from the three species, with particular conservation of the repetitive motifs. Northern blot analysis revealed that the mRNA is larger than 11 kb and is expressed exclusively in the piriform glands of the spider. Phylogenetic analysis of the C-terminal regions of the new proteins with published spidroins robustly shows that the piriform sequences form an ortholog group.

2016

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The external morphology of the spinning apparatus of the troglobitic spider species Rhode aspinifera (Nicolic, 1963) was studied using scanning electron microscopy. Three pairs of spinnerets in adult stages of both sexes are equipped with three kinds of spigots (i.e. external outlets of silk spinning glands). The silk-producing organ is equipped with the same types of glands (Glandulae ampullaceae, Gl. piriformes and Gl. psudaciniformes) as those of other dysderids studied so far; however, the total number of their spigots (and the glands connected to them) is very small. This may be an adaptive response to reduce the production of energetically costly silk.

American Museum Novitates, 2007

We present the first observations of the combing and attaching behavior in the subfamily Prithinae (Filistatidae), taken from Misionella mendensis. We compare its web architecture with that of other prithines (Pritha nana and Pikelinia sp. from Chile) and filistatines (Kukulcania hibernalis and Filistata insidiatrix). The combing behavior of M. mendensis corresponds to the stereotyped type I combing behavior, as is known for other filistatids. However, M. mendensis attaches the cribellar segments in a unique way, splitting the cribellar segment longitudinally and pushing each half to the substrate, attaching the silk with the tarsi of both legs IV simultaneously. These stereotyped movements result in web units of a very characteristic structure. We report the same split attachment behavior in the prithine Pikelinia tambilloi. We scored these observations into a previous dataset for filistatid relationships. Because of the missing observations on attachment behavior in the North American basal genus Filistatinella, the sister group of all other prithines, the evolution of split cribellar strands is a potential synapomorphic characteristic for the Prithinae, or at least the subgroup excluding its basal taxon.

Arachnologische Mitteilungen, 2011

Scientific Reports, 2019

Spiders are commonly found in terrestrial environments and many rely heavily on their silks for fitness related tasks such as reproduction and dispersal. Although rare, a few species occupy aquatic or semi-aquatic habitats and for them, silk-related specializations are also essential to survive in aquatic environments. Most spider silks studied to date are from cob-web and orb-web weaving species, leaving the silks from many other terrestrial spiders as well as water-associated spiders largely undescribed. Here, we characterize silks from three Dictynoidea species: the aquatic spiders Argyroneta aquatica and Desis marina as well as the terrestrial Badumna longinqua. From silk gland RNA-Seq libraries, we report a total of 47 different homologs of the spidroin (spider fibroin) gene family. Some of these 47 spidroins correspond to known spidroin types (aciniform, ampullate, cribellar, pyriform, and tubuliform), while other spidroins represent novel branches of the spidroin gene family....

The common house spider alters the material and mechanical properties of cobweb silk in response to different prey., 2008

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