Smelling chemosensory signals of males in anxious versus nonanxious condition increases state anxiety of female subjects

The hypothesis of this experiment was that humans in an anxious state compared with a nonanxious state are able to increase anxiety levels in other humans via their body odors. Specifically, we hypothesized that male chemosensory anxiety signals compared with neutral chemosignals increase state anxiety of female subjects. Thirteen male subjects participated in 2 different sweat donation sessions: chemosignals were collected during participation in a high rope course (anxiety condition) and in an ergometer workout (neutral condition). State and trait anxiety were evaluated in 20 female odor recipients using Spielberger's state-trait anxiety inventory in a double-blind design. Comparison of state anxiety of odor donors between control and anxiety condition differed significantly indicating that our model of anxiety induction successfully led to the expected change in emotion. Comparison of state anxiety of odor recipients showed a trend toward higher state anxiety in the anxiety condition compared with the neutral condition after 5 min of odor exposure. After 20 min of odor exposure, state anxiety of female subjects was significantly higher during the perception of sweat collected during the anxiety condition in comparison with the perception of sweat collected during the neutral condition. This experiment gives evidence that male anxiety chemosignals compared with neutral chemosignals are capable of inducing an increased state anxiety in female subjects.     

Suitability of different media for in vitro cultivation of the ruminal protozoa species Entodinium caudatum, Eudiplodinium maggii, and Epidinium ecaudatum

Three protozoal cultivation media were tested to determine the medium which best facilitated growth and viability of key B-type ciliates isolated from the sheep rumen. Entodinium caudatum and Eudiplodinium maggii were grown anaerobically in 50-ml flasks for 32 days in Caudatum-type (C), Kisidayova (K) or Dehority (M) medium. On day 32, in media K and M, E. caudatum cell counts were high with 5.6 × 10³ and 7.8 × 10³ mL⁻¹, respectively, and the proportion of dead cells was low with 0.6 and 1.4%, respectively. E. maggii concentrations when grown in medium M and C were 2.7 × 10³ and 2.4 × 10³ mL⁻¹, respectively, with 3.9 and 14.1% dead cells. Medium M, which favoured growth of both protozoa species, was tested again and Epidinium ecaudatum was included. Protozoa were grown for a 4-month period and samples were taken in the last two months on days 1, 7, 35 and 57. Average cell concentrations were 10.0, 0.8 and 0.5 × 10³ mL⁻¹ for E. caudatum, E. maggii, and E. ecaudatum, respectively. In conclusion, medium M would appear to be the best choice for cultivating these three species in one medium.     

Extreme aggression in male squid induced by a β-MSP-like pheromone

Male-male aggression is widespread in the animal kingdom and subserves many functions related to the acquisition or retention of resources such as shelter, food, and mates. These functions have been studied widely in the context of sexual selection, yet the proximate mechanisms that trigger or strengthen aggression are not well known for many taxa. Various external sensory cues (visual, audio, chemical) acting alone or in combination stimulate the complex behavioral interactions of fighting behaviors. Here we report the discovery of a 10 kDa protein, termed Loligo β-microseminoprotein (Loligo β-MSP), that immediately and dramatically changes the behavior of male squid from calm swimming and schooling to extreme fighting, even in the absence of females. Females synthesize Loligo β-MSP in their reproductive exocrine glands and embed the protein in the outer tunic of egg capsules, which are deposited on the open sea floor. Males are attracted to the eggs visually, but upon touching them and contacting Loligo β-MSP, they immediately escalate into intense physical fighting with any nearby males. Loligo β-MSP is a distant member of the chordate β-microseminoprotein family found in mammalian reproductive secretions, suggesting that this gene family may have taxonomically widespread roles in sexual competition.     

Ancient ubiquitous protein 1 (AUP1) localizes to lipid droplets and binds the E2 ubiquitin conjugase G2 (Ube2g2) via its G2 binding region

Lipid droplets (LDs), the major intracellular storage sites for neutral lipids, consist of a neutral lipid core surrounded by a phospholipid monolayer membrane. In addition to their function in lipid storage, LDs participate in lipid biosynthesis and recently were implicated in proteasomal protein degradation and autophagy. To identify components of the protein degradation machinery on LDs, we studied several candidates identified in previous LD proteome analyses. Here, we demonstrate that the highly conserved and broadly expressed ancient ubiquitous protein 1 (AUP1) localizes to LDs, where it integrates into the LD surface in a monotopic fashion with both termini facing the cytosol. AUP1 contains a C-terminal domain with strong homology to a domain known as G2BR, which binds E2 ubiquitin conjugases. We show that AUP1, by means of its G2BR domain, binds to Ube2g2. This binding is abolished by deletion or mutation of the G2BR domain, although the LD localization of AUP1 is not affected. The presence of the AUP1-Ube2g2 complex at LDs provides a direct molecular link between LDs and the cellular ubiquitination machinery.     

Structure of collagen receptor integrin α(1)I domain carrying the activating mutation E317A

We have analyzed the structure and function of the integrin α₁I domain harboring a gain-of-function mutation E317A. To promote protein crystallization, a double variant with an additional C139S mutation was used. In cell adhesion assays, the E317A mutation promoted binding to collagen. Similarly, the double mutation C139S/E317A increased adhesion compared with C139S alone. Furthermore, soluble α₁I C139S/E317A was a higher avidity collagen binder than α₁I C139S, indicating that the double variant represents an activated form. The crystal structure of the activated variant of α₁I was solved at 1.9 Å resolution. The E317A mutation results in the unwinding of the αC helix, but the metal ion has moved toward loop 1, instead of loop 2 in the open α₂I. Furthermore, unlike in the closed αI domains, the metal ion is pentacoordinated and, thus, prepared for ligand binding. Helix 7, which has moved downward in the open α₂I structure, has not changed its position in the activated α₁I variant. During the integrin activation, Glu³³⁵ on helix 7 binds to the metal ion at the metal ion-dependent adhesion site (MIDAS) of the β₁ subunit. Interestingly, in our cell adhesion assays E317A could activate collagen binding even after mutating Glu³³⁵. This indicates that the stabilization of helix 7 into its downward position is not required if the α₁ MIDAS is already open. To conclude, the activated α₁I domain represents a novel conformation of the αI domain, mimicking the structural state where the Arg²⁸⁷-Glu³¹⁷ ion pair has just broken during the integrin activation.     

Human lysophosphatidylcholine acyltransferases 1 and 2 are located in lipid droplets where they catalyze the formation of phosphatidylcholine

Phosphatidylcholine (PC) is synthesized by two different pathways, the Lands cycle and the Kennedy pathway. The recently identified key enzymes of the Lands cycle, lysophosphatidylcholine acyltransferase 1 and 2 (LPCAT1 and -2), were reported to localize to the endoplasmic reticulum and to function in lung surfactant production and in inflammation response. Here, we show in various mammalian cell lines that both enzymes additionally localize to lipid droplets (LDs), which consist of a core of neutral lipids surrounded by a monolayer of phospholipid, mainly PC. This dual localization is enabled by the monotopic topology of these enzymes demonstrated in this study. Furthermore, we show that LDs have the ability to locally synthesize PC and that this activity correlates with the LPCAT1 and -2 expression level. This suggests that LPCAT1 and -2 have, in addition to their known function in specialized cells, a ubiquitous role in LD-associated lipid metabolism.