(1R,4′S)-4-(tert-Butyl­dimethyl­silan­oxy)-1-[2,2-dimethyl-3-(p-tolyl­sulfon­yl)-1,3-oxazolidin-4-yl]but-2-yn-1-ol

The chiral title compound, C22H35NO5SSi, is a precursor of novel furan­omycin derivatives. It crystallizes with two molecules in the asymmetric unit; these show different conformations of the silyl substitutent, as indicated by the Si—O—C—C torsion angles of 41.4 (7) and −84.5 (5)° in the two mol­ecules. The anti configuration of the adjacent stereogenic centers is consistent with the Felkin–Anh model. Each of the two crystallographically independent mol­ecules is connected with a neighbouring mol­ecule of the same type via two symmetry-equivalent O—H⋯O hydrogen bonds

Ethyl 2-[4-(benzyloxy)anilino]-4-oxo-4,5-dihydro­furan-3-carboxyl­ate

In the title compound, C20H19NO5, the dihydro­furan ring is almost planar [maximum deviation of 0.021 (2)°] and makes dihedral angles of 28.1 (7) and 54.5 (5)° with the benzyl and phenyl­amino rings, respectively. The mol­ecular packing is stabilized by intra­molecular N—H⋯O hydrogen bonds and inter­molecular C—H⋯O inter­actions

Innervation patterns of sea otter (Enhydra lutris) mystacial follicle-sinus complexes

Sea otters (Enhydra lutris) are the most recent group of mammals to return to the sea, and may exemplify divergent somatosensory tactile systems among mammals. Therefore, we quantified the mystacial vibrissal array of sea otters and histologically processed follicle-sinus complexes (F - SCs) to test the hypotheses that the number of myelinated axons per F - SC is greater than that found for terrestrial mammalian vibrissae and that their organization and microstructure converge with those of pinniped vibrissae. A mean of 120.5 vibrissae were arranged rostrally on a broad, blunt muzzle in 7–8 rows and 9–13 columns. The F-SCs of sea otters are tripartite in their organization and similar in microstructure to pinnipeds rather than terrestrial species. Each F-SC was innervated by a mean 1339 ± 408.3 axons. Innervation to the entire mystacial vibrissal array was estimated at 161,313 axons. Our data support the hypothesis that the disproportionate expansion of the coronal gyrus in somatosensory cortex of sea otters is related to the high innervation investment of the mystacial vibrissal array, and that quantifying innervation investment is a good proxy for tactile sensitivity. We predict that the tactile performance of sea otter mystacial vibrissae is comparable to that of harbor seals, sea lions and walruses

Comparing vibrissal morphology and infraorbital foramen area in pinnipeds

Pinniped vibrissae are well-adapted to sensing in an aquatic environment, by being morphologically diverse and more sensitive than those of terrestrial species. However, it is both challenging and time-consuming to measure vibrissal sensitivity in many species. In terrestrial species, the infraorbital foramen (IOF) area is associated with vibrissal sensitivity and increases with vibrissal number. While pinnipeds are thought to have large IOF areas, this has not yet been systematically measured before. We investigated vibrissal morphology, IOF area, and skull size in 16 species of pinniped and 12 terrestrial Carnivora species. Pinnipeds had significantly larger skulls and IOF areas, longer vibrissae, and fewer vibrissae than the other Carnivora species. IOF area and vibrissal number were correlated in Pinnipeds, just as they are in terrestrial mammals. However, despite pinnipeds having significantly fewer vibrissae than other Carnivora species, their IOF area was not smaller, which might be due to pinnipeds having vibrissae that are innervated more. We propose that investigating normalized IOF area per vibrissa will offer an alternative way to approximate gross individual vibrissal sensitivity in pinnipeds and other mammalian species. Our data show that many species of pinniped, and some species of felids, are likely to have strongly innervated individual vibrissae, since they have high values of normalized IOF area per vibrissa. We suggest that species that hunt moving prey items in the dark will have more sensitive and specialized vibrissae, especially as they have to integrate between individual vibrissal signals to calculate the direction of moving prey during hunting

An approach towards azafuranomycin analogs by gold-catalyzed cycloisomerization of allenes: synthesis of (αS,2R)-(2,5-dihydro-1H-pyrrol-2-yl)glycine

The synthesis of (αS,2R)-(2,5-dihydro-1H-pyrrol-2-yl)glycine (22, normethylazafuranomycin) by the gold-catalyzed cycloisomerization of α-aminoallene 17 is described. The target molecule was synthesized in 13 linear steps from Cbz-protected Garner aldehyde (R)-2 in an overall yield of 2.4%. The approach was first examined in model studies, which afforded the alkylated azafuranomycin derivative 13a in 2.9% yield over 12 steps

Coping with heat: function of the natal coat of cape fur seal (Arctocephalus Pusillus Pusillus) pups in maintaining core body temperature.

Cape fur seal (Arctocephalus pusillus) pups spend the first weeks of life exclusively or mainly ashore. They are exposed to intense solar radiation and high temperatures for long time periods, which results in temperatures up to at least 80°C on their black natal coat. To test the hypothesis that the natal coat has a crucial function in coping with these extreme conditions, we investigated the insulating properties of the natal coat in six captive newborn Cape fur seals during the first 50 days after birth. The natal fur differs from the adult fur not only in colour, but also in density, structure, and water repellence. We measured temperature on the fur surface and within the fur, as well as skin and rectal temperature under varying environmental conditions, comparable to the species' habitat. Experiments were designed to not influence the spontaneous behaviour of the pups. Rectal temperature was constant as long as the pups stayed dry, even during long-lasting intense solar radiation for up to 3 h. Skin temperature remained close to rectal temperature as long as the fur was dry, while with wet fur, skin temperature was significantly reduced as well. Our results show that the natal coat provides an effective insulation against overheating. The severely reduced insulation of wet natal fur against cold supports the assumption that the natal fur is an adaptation to the pups' terrestrial phase of life

T_body and T_skin of the pups with wet and dry fur.

<p>T_body with dry fur (green diamonds, green regression line, N = 23) and wet fur (turquoise filled circles, N = 3) as well as T_skin with dry fur (red circles, red regression line, N = 279) and wet fur (blue circles, blue regression line, N = 28) against T_air. Mean T_skin with dry fur is 38.4±1.7°C, mean T_skin with wet fur is 35.8±1.3°C, which is significantly lower than with dry fur (<i>p</i>≤0.0001). T_body is constant with no significant difference between wet and dry fur. The slope of regression of T_body is with 0.002 again practically constant, while the regressions of T_skin ascend by 0.32 (dry fur) and 0.13 (wet fur).</p

T_body, T_skin, T_fur and T_surface of the pups with wet and dry fur.

<p>Minimum (T_min), maximum (T_max) and mean (T_mean) temperatures of the pups' fur surface, air inside the fur, skin and body core along with temperature range, standard deviation (s.d.) and number of measurements (N). Total includes the data of all investigated pups with dry and wet fur. Beneath the data of all pups are sorted by wet or dry fur conditions.</p

Cape fur seal pups hauling out under intense solar radiation.

<p>The pups, aged 18 and 28 days, hauled out in the sun for 1.5 h, T_air  = 31.3°C. T_surface increased up to 78.7°C on their backs.</p

Reduction of T_surface on hauled out pups by wind forced convection.

<p>Pups hauling out under solar radiation with sudden appearance of a light breeze of wind force 1–2 (Beaufort), corresponding to 0.2–3.3 m/s. (A) Pup with T_max = 61.2°C on the surface, T_air = 17.3°C. (B) Decreased T_surface after light breeze for 5 s to T_max = 58.8°C (3.9%). (C) Pup with T_max = 72.3°C on the surface, T_air = 23.8°C. (D) After 42 s of light breeze T_surface decreased to T_max = 47.3°C (34.6%).</p