Multiple preferred escape trajectories are explained by a geometric model incorporating prey\u27s turn and predator attack endpoint

The escape trajectory (ET) of prey - measured as the angle relative to the predator\u27s approach path - plays a major role in avoiding predation. Previous geometric models predict a single ET; however, many species show highly variable ETs with multiple preferred directions. Although such a high ET variability may confer unpredictability to avoid predation, the reasons why animals prefer specific multiple ETs remain unclear. Here, we constructed a novel geometric model that incorporates the time required for prey to turn and the predator\u27s position at the end of its attack. The optimal ET was determined by maximizing the time difference of arrival at the edge of the safety zone between the prey and predator. By fitting the model to the experimental data of fish Pagrus major, we show that the model can clearly explain the observed multiple preferred ETs. By changing the parameters of the same model within a realistic range, we were able to produce various patterns of ETs empirically observed in other species (e.g., insects and frogs): a single preferred ET and multiple preferred ETs at small (20-50°) and large (150-180°) angles from the predator. Our results open new avenues of investigation for understanding how animals choose their ETs from behavioral and neurosensory perspectives

Multiple visual stimuli in Pacific staghorn sculpin Leptocottus armatus: Can fish modulate their escape response while escaping?

The effect of multiple visual stimuli replicating predator strikes from two opposite sides were investigated in the Pacific staghorn sculpin (Leptocottus armatus) at different time points during the escape response. To trigger the escape responses, we used a visual stimulation (e.g., a looming image of an approaching black circle) simulating a predator strike. For the control treatment, only a single visual stimulus was used while for the treatments we played a second stimulus, simultaneously or with a delay of 33 or 83 milliseconds. Our results revealed that a second stimulus with a delay of 33 ms affects the escape trajectory with a change of turning angle during the stage one of the escape response. Such findings tend to suggest that the sensory feedback mechanism modulates the escape response

Alkoxy Substituted Brominated closo-Dodecaborates with Functionalized Aliphatic Spacers

The utilization of dodecaborate boron clusters, B12X122– (X = Cl, Br, or I), as membrane carriers has been demonstrated recently, and their activity is known to be due to their superchaotropic nature. In this work, the mono alkylation of [B12Br11OH]2– to functionalize it with an aliphatic spacer was developed with a view to expanding the known chemical space of membrane carriers based on B12Br122–. A new and improved facile route for the preparation of [B12Br11OH]2–, which is an important precursor to other [B12Br11OR]2– species, is reported. Various alkoxylated [B12Br11O(CH2)5Z]2– (Z = OH, N(CO)2C6H4, CN and N3) derivatives were prepared via a divergent synthesis based on [B12Br11O(CH2)5Br]2–. One of the newly synthesized compounds was utilized as a membrane carrier and its impact on cell viability was examined

Escaping from multiple visual threats: modulation of escape responses in Pacific staghorn sculpin (Leptocottus armatus)

Fish perform rapid escape responses to avoid sudden predatory attacks. During escape responses, fish bend their bodies into a C-shape and quickly turn away from the predator and accelerate. The escape trajectory is determined by the initial turn (stage 1) and a contralateral bend (stage 2). Previous studies have used a single threat or model predator as a stimulus. In nature, however, multiple predators may attack from different directions simultaneously or in close succession. It is unknown whether fish are able to change the course of their escape response when startled by multiple stimuli at various time intervals. Pacific staghorn sculpin (Leptocottus armatus) were startled with a left and right visual stimulus in close succession. By varying the timing of the second stimulus, we were able to determine when and how a second stimulus could affect the escape response direction. Four treatments were used: a single visual stimulus (control); or two stimuli coming from opposite sides separated by a 0 ms (simultaneous treatment), 33 ms or 83 ms time interval. The 33 ms and 83 ms time intervals were chosen to occur either side of a predicted 60 ms visual escape latency (i.e. during stage 1). The 0 ms and 33 ms treatments influenced both the escape trajectory and the stage 1 turning angle, compared with a single stimulation, whereas the 83 ms treatment had no effect on the escape trajectory. We conclude that Pacific staghorn sculpin can modulate their escape trajectory only between stimulation and the onset of the response, but the escape trajectory cannot be modulated after the body motion has started

Suppressive effects of sugarcane molasses concentrate on starch-induced hyperglycemia in mice

Molasses is a by-product from refining sugarcane beets into sugar. In this study, we assessed the inhibitory effect of sugarcane molasses concentrate (SMC) on postprandial hyperglycemia using a mouse model. Starch administration into male ICR mice increased blood glucose levels, reaching a peak 60 min after administration. The simultaneous administration of SMC markedly suppressed this increase, and the area under the curve was reduced until 240 min after administration. Simultaneous administration of an ethanol-precipitated fraction (Et-Fr) of SMC with starch also exerted significant inhibitory effects. Ad libitum consumption of Et-Fr for 6 weeks did not exert any changes on fasting blood glucose levels. In vitro experiments showed that SMC and Et-Fr significantly inhibited α-glucosidase but not α-amylase activity. These results suggest that SMC has the potential to suppress postprandial hyperglycemia via inhibition of α-glucosidase