A drug molecule can bind in various orientations to a DNA strand. Nature of the binding decides the functionality and efficacy of the drug. To innovate a new method to detect the nature of binding of a drug to DNA strands, herein we have used the dipole−dipole interaction driven Forster resonance energy transfer (FRET) between carbon nanoparticles (CNPs) and a DNA-bound small molecule, (E)-3-ethyl-2-(4-(pyrrolidin-1-yl)styryl)benzo[d]thiazol-3-ium (EPSBT), which belongs to the hemicyanine family and binds typically to the minor groove of a DNA duplex. EPSBT was designed to obtain appreciable fluorescence quantum yield, which constructed an efficient FRET pair with the synthesized CNPs. The tested compound prefers the thymine nucleobase to bind to the DNA strand. Orientation of its dipole on attachment to the DNA strand and the donor−acceptor distance dictate the FRET efficiency with the CNPs. The results provided a precise estimation of the nature of binding of EPSBT to the DNA backbone and, hence, supposedly will help in deciding the functional efficacy.

Mixed-species groups occur across a wide range of faunal communities and provide several benefits to members. While zebrafish have often been observed to form mixed-species shoals with coexisting species, the factors determining their occurrence are not yet fully understood. Shoals comprising zebrafish (Danio rerio), flying barbs (Esomus danricus), and whitespots (Aplocheilus panchax) were collected from a stagnant canal at Haringhata (West Bengal, India), and using laboratory-based experiments, we deciphered likely drivers of mixed-species shoaling among zebrafish. Experiments assessing foraging efficiency revealed that the amount of food consumed by zebrafish individuals in mixed shoals was comparable to the amount consumed by these individuals in conspecific shoals. Within mixed-species shoals, zebrafish individuals, despite being smaller than the other species, consumed a comparable amount of food as the other species. Shoal choice experiments revealed that under predator risk, zebrafish associate more with mixed shoals and showed comparable associations to shoals differing in the abundance of conspecifics. Furthermore, zebrafish preferred associating with familiar conspecifics over unfamiliar mixed and unfamiliar conspecific shoals. Therefore, equitable food consumption in mixed shoals, greater association with mixed shoals in the presence of predators, and familiarity were important in driving zebrafish towards mixed-species shoaling.

Shoaling in fishes is regulated by factors like predation, vegetation cover, water flow and food availability. Shoals detect and respond to changes in these ecological factors using a multimodal sensory system. Here, we examine the immediate response of wild-caught zebrafish (Danio rerio)shoals to cues from its natural predator, the snakehead (Channa sp.). Zebrafish shoals were recorded upon exposure to (1) olfactory predator cues, (2) visual predator cues, (3) both cues together, and (4) no cue. We tracked individuals and analysed shoal responses across these treatments. We found that compared to control treatments, shoals receiving either visual or olfactory cues had significantly greater: (i) cohesion, (ii) polarization and (iii) velocity. Interestingly, when the shoals received both cues simultaneously, the cohesion, polarization and velocity decreased and a significantly greater number of individual freezing events occurred. Therefore, zebrafish relied on both visual and olfactory cues to escape predation. However, when shoals were presented with both cues together, while freezing frequency increased, other responses were comparable to control treatments where no predator cue was provided. While this study indicates that multimodal cues elicit a different anti-predator response than the cues singly, more experiments are required to identify the underlying cause of this behaviour.

Animals are known to acquire and store information of their environment in order to enhance their performance in different tasks like foraging, migration and breeding. Having information regarding nesting sites would be particularly useful when they have to relocate. In the current study, we asked if having information of a new nest prior to or at the onset of relocation has a positive impact on the ability of ant colonies to relocate. We performed five sets of experiments on a ponerine ant species Diacamma indicum that recruits nestmates solely by tandem running. By analyzing data of 4756 unique ants across 61 colonies, we found that, access to information of the new nest for 1 day prior to the relocation did not give any significant advantage as compared to no prior information of the new nest. However, access to information for 7 days prior to relocation resulted in 50% increase in the number of tandem leaders and reduction of the transport time by an average of 49%. Our data on providing information at the onset of relocation indicates that introducing explorers to the new nest did not aid the process of relocation but when information of a new nest was self‐acquired, there was a reduction in discovery time by 50% and also in the transport time per unit distance for relocation into a new nest. Having information regarding only the surroundings and not the nest at the onset of a relocation did not give any significant advantages. Further, the manner in which work was organized during the relocation process was not significantly influenced by prior information across any of the treatments. Our findings suggest that information of new nest is important and when such information is self‐acquired at the onset of relocation or is available for a long enough duration, it has a positive influence in the process of relocation in this ant species.