The folding of a recombinant spider silk protein-polymer in the presence of the tri-methylamine osmolytes TMANO and Betaine in 80% H sub(2)O is reported. Circular dichroism measurements (CD) reveal ...an increase in alpha -helical secondary structure with increasing osmolyte concentrations, as determined by an increase in ellipticity at 222 nm. Consistent with this observation, the signal for random coil sampling, observed at 205 nm, is greatly reduced with increasing trimethylamine. Fluorescence spectra of a single tyrosine positioned within the conserved 33-amino acid repeat primary sequence (of the spider-silk mimetic) complements the conformational changes observed by CD. Importantly, there is a correlation between the number of Alkyl-groups (CH sub(3)-) on the amine of the osmolyte and enhanced helicity of the 15-repeat silk-mimetic for the osmolytes tested, ie TMANO, Betaine, Sarcosine and Glycine. These preliminary results are applicable to storing and processing recombinant silk sequences in H sub(2)O, an important mile-stone for widespread use of recombinant silk polymers.
Alanine oligomers provide a key structure for silk fibers from spider and wild silkworms.We report on structural analysis of l-alanyl-l-alanyl-l-alanyl-l-alanine (Ala) sub(4) with anti-parallel (AP) ...beta-structures using X-ray and solid-state NMR. All of the Ala residues in the (Ala) sub(4) are in equivalent positions, whereas for alanine trimer (Ala) sub(3) there are two alternative locations in a unit cell as reported previously (Fawcett and Camerman, Acta Cryst., 1975, 31, 658-665). (Ala) sub(4) with AP beta-structure is more stable than AP-(Ala) sub(3) due to formation of the stronger hydrogen bonds. The intermolecular structure of (Ala) sub(4) is also different from polyalanine fiber structure, indicating that the interchain arrangement of AP beta-structure changes with increasing alanine sequencelength. Furthermore the precise super(1)H positions, which are usually inaccesible by X-ray diffraction method, are determined by high resolution super(1)H solid state NMR combined with the chemical shift calculations by the gauge-including projector augmented wave method. copy 2013 Wiley Periodicals, Inc. Biopolymers 101: 13-20, 2014.
We report a case of envenomation by Trachelas tranquillus (Hentz) in Connecticut in late September 2013. The bitten subject, a 50 yr-old-female Caucasian, reported a painful wasp-like sting and ...brushed the spider from her leg. An erythematous macule formed at the site of the bite. The macule was gone by the next day and there was no associated necrosis. The spider was collected and brought to our laboratory for identification. This is the second confirmed case of envenomation by T. tranquillus and the only case reported from Connecticut.
Humans can store, maintain, and retrieve an impressive amount of information-but the processes that support accurate knowledge can also lead to errors, such as the false belief that humans swallow ...eight spiders in their sleep each year. In this chapter, we review characteristics of the knowledge base and explore how five adaptive properties that support accurate knowledge can also lead to the learning, storage, and retrieval of falsehoods. First, people exhibit a bias to believe information is true since, most of the time, incoming information is indeed true. Second, we utilize a fluency-based heuristic for judging truth since-again, most of the time-easy processing reliably signals that something is true. Third, the knowledge base is productive: people use existing knowledge to make new inferences, which are typically accurate but occasionally are inappropriate and result in errors. Fourth, existing knowledge supports new learning, so our ingrained misconceptions can foster new errors and interfere with learning the truth. Fifth, because it would be too taxing to carefully compare all incoming information to stored knowledge, we do not require a perfect match and often accept information as "good enough." As a result, errors that are similar to the truth often slip by undetected, and sometimes are later reproduced. Finally, we discuss methods for correcting errors and potential barriers to the correction of misconceptions. In particular, it is essential to refute the error as well as provide a simple alternative to replace it. Overall, the processes that support accurate knowledge and false beliefs are the same, and can lead to competing representations in memory.
Morphological and SEM analyses were carried out on the chorion of freshly laid eggs, eggs at different time intervals after oviposition and after hatching of a Namibian segestriid spider Ariadna sp. ...The eggs laid in the laboratory are held together by a milky-white mucous secretion that gradually decreases until it almost entirely disappears. The eggs are spherical/ellipsoid in shape and, only after the reduction of the secretion, are granular structures of the exochorion evident. Granules are arranged in a single layer and lie on a compact endochorion covering the thin vitelline membrane. No significant difference was found in the chorion of hatched eggs compared to eggs a few hours after oviposition.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We sampled lepidopteran-feeding shelters on three species of ferns in Maine to determine use by spiders (Araneae). These feeding shelters were colonized by at least 39 species of spiders, ...representing 13 families and 33 genera. Most spider-inhabited shelters were on cinnamon fern (82.0%), with fewer on royal fern (12.8 %) and bracken fern (5.1%). Species richness was greater for web spinners (n= 26) than for hunters (n= 13). Abundance of individuals, however, favored hunters (n= 300) over web spinners (n= 186). Juvenile spiders (n= 410) were more frequent inhabitants than adult spiders (n= 78); females (n= 60) more frequent than males (n = 18). Shelters with single-spider occupants (n= 223) were more prevalent than shelters with multiple-spider occupants (n= 77). The proportion of shelters inhabited by spiders increased from June to mid-August, primarily through the addition of juveniles, and declined thereafter as the ferns senesced. Spider-habitation frequencies of shelters were similar each of the three study years (~ 35% of shelters occupied by spiders each year) despite unequal sample sizes between study sites and among fern species, and years (2012-2014). Spiders used lepidopteran-feeding shelters as refugia for molting and laying eggs, thus allowing spiders to conserve time, energy, and resources (silk).Original Abstract: Nous avons echantillonne des abris d'alimentation de lepidopteres sur trois especes de fougeres dans le Maine pour determiner leur utilisation par les araignees (Araneae). Ces abris d'alimentation etaient colonises par au moins 39 especes d'araignees, representant 13 familles et 33 genres. La majorite des abris occupes par des araignees etaient situes sur l'osmonde cannelle (82,0%), et un nombre moindre sur l'osmonde royale (12,8%) et la fougere-aigle (5,1%). La richesse specifique etait plus elevee chez les araignees tisseuses de toile (n= 26) que chez les araignees chasseuses ( super(n)= 13). Cependant, l'abondance des individus etait plus elevee chez les chasseuses (n= 300) que chez les tisseuses de toile (n= 186). Les araignees juveniles (n = 410) etaient plus frequentes que les araignees adultes (n= 78); les femelles (n= 60) etaient plus frequentes que les males (n = 18). Les abris occupes par une seule araignee (n= 223) etaient plus nombreux que ceux occupes par plusieurs araignees (n= 77). La proportion des abris occupes par des araignees a augmente entre le mois de juin et la mi-aout, surtout en raison d'une augmentation des juveniles, puis a diminue par la suite, avec la senescence des fougeres. La frequence d'occupation des abris par les araignees etait similaire a chacune des trois annees de l'etude (environ 35% des abris etaient occupes par des araignees chaque annee), malgre un echantillonnage de taille differente entre les sites d'etudes, les especes de fougeres, et les annees (de 2012 a 2014). Les araignees utilisaient les abris d'alimentation des lepidopteres comme refuge pour muer et pondre leurs oeufs, ce qui leur permettait d'epargner du temps, de l'energie et des ressources (soie).
Profile of Larry J. Young Nybo, Kristie
BioTechniques,
2011-July-01, 20110701, Letnik:
51, Številka:
1
Journal Article
Recenzirano
Odprti dostop
What is the main goal of your laboratory? My fundamental goal is to find out how the genome and brain influence diversity in behavior. I grew up on a farm and spent a lot of time observing animals. ...Early on, I became fascinated by the fact that different species have different personality types and inborn behaviors. For example, different species of spiders weave different webs; they dont learn the patterns from their parents, but are born with that information.
PDF
