Bumble bees’ food preferences are jointly shaped by rapid evaluation of nectar sugar concentration and viscosity

Animals are often assumed to follow a strategy of energy maximization, and therefore should evaluate feeding options based on energy intake rates. However, at the proximal level, a direct estimate of energy intake rates, if that is possible at all, might require postabsorptive senses with relatively longer processing times, whereas an indirect estimate of energy intake through proxies like pre-absorptive senses of different sensory food properties might support rapid foraging decisions. Here, we show that nectar sugar concentration (sweetness) and nectar viscosity (resistance) drive preferences of bumble bees, Bombus terrestris, classical models for economic and foraging decision making. Using a tasteless/odourless biopolymer (Tylose), we created feeding options that differed in sweetness and resistance, properties that affect energy intake rate and can be immediately sensed. When energy intake rates were similar, bumble bees developed preferences based on sweetness and resistance. When energy intake rates were different, but sweetness and resistance were balanced against each other, bees developed no preferences. Decision dynamics during training indicated that bumble bees simultaneously evaluated sweetness and resistance to make decisions quickly (in seconds). These results suggest that bumble bees’ food preferences are jointly affected by the immediate sensation of nectar sweetness and resistance as positively and negatively reinforcing properties, respectively, indicating a pre-absorptive proximate mechanism for rapid energy-sensitive decisions in bumble bees.Animals are often assumed to follow a strategy of energy maximization, and therefore should evaluate feeding options based on energy intake rates. However, at the proximal level, a direct estimate of energy intake rates, if that is possible at all, might require postabsorptive senses with relatively longer processing times, whereas an indirect estimate of energy intake through proxies like pre-absorptive senses of different sensory food properties might support rapid foraging decisions. Here, we show that nectar sugar concentration (sweetness) and nectar viscosity (resistance) drive preferences of bumble bees, Bombus terrestris, classical models for economic and foraging decision making. Using a tasteless/odourless biopolymer (Tylose), we created feeding options that differed in sweetness and resistance, properties that affect energy intake rate and can be immediately sensed. When energy intake rates were similar, bumble bees developed preferences based on sweetness and resistance. When energy intake rates were different, but sweetness and resistance were balanced against each other, bees developed no preferences. Decision dynamics during training indicated that bumble bees simultaneously evaluated sweetness and resistance to make decisions quickly (in seconds). These results suggest that bumble bees’ food preferences are jointly affected by the immediate sensation of nectar sweetness and resistance as positively and negatively reinforcing properties, respectively, indicating a pre-absorptive proximate mechanism for rapid energy-sensitive decisions in bumble bees

Cardiac Hypertrophy Involves Both Myocyte Hypertrophy and Hyperplasia in Anemic Zebrafish

Background: An adult zebrafish heart possesses a high capacity of regeneration. However, it has been unclear whether and how myocyte hyperplasia contributes to cardiac remodeling in response to biomechanical stress and whether myocyte hypertrophy exists in the zebrafish. To address these questions, we characterized the zebrafish mutant tr265/tr265, whose Band 3 mutation disrupts erythrocyte formation and results in anemia. Although Band 3 does not express and function in the heart, the chronic anemia imposes a sequential biomechanical stress towards the heart. Methodology/principal findings: Hearts of the tr265/tr265 Danio rerio mutant become larger than those of the sibling by week 4 post fertilization and gradually exhibit characteristics of human cardiomyopathy, such as muscular disarray, re-activated fetal gene expression, and severe arrhythmia. At the cellular level, we found both increased individual cardiomyocyte size and increased myocyte proliferation can be detected in week 4 to week 12 tr265/tr265 fish. Interestingly, all tr265/tr265 fish that survive after week-12 have many more cardiomyocytes of smaller size than those in the sibling, suggesting that myocyte hyperplasia allows the long-term survival of these fish. We also show the cardiac hypertrophy process can be recapitulated in wild-type fish using the anemia-inducing drug phenylhydrazine (PHZ). Conclusions/significance: The anemia-induced cardiac hypertrophy models reported here are the first adult zebrafish cardiac hypertrophy models characterized. Unlike mammalian models, both cardiomyocyte hypertrophy and hyperplasia contribute to the cardiac remodeling process in these models, thus allowing the effects of cardiomyocyte hyperplasia on cardiac remodeling to be studied. However, since anemia can induce effects on the heart other than biomechanical, non-anemic zebrafish cardiac hypertrophy models shall be generated and characterized

Space advanced technology demonstration satellite

The Space Advanced Technology demonstration satellite (SATech-01), a mission for low-cost space science and new technology experiments, organized by Chinese Academy of Sciences (CAS), was successfully launched into a Sun-synchronous orbit at an altitude of similar to 500 km on July 27, 2022, from the Jiuquan Satellite Launch Centre. Serving as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit, SATech-01 is equipped with 16 experimental payloads, including the solar upper transition region imager (SUTRI), the lobster eye imager for astronomy (LEIA), the high energy burst searcher (HEBS), and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer (CPT). It also incorporates an imager with freeform optics, an integrated thermal imaging sensor, and a multi-functional integrated imager, etc. This paper provides an overview of SATech-01, including a technical description of the satellite and its scientific payloads, along with their on-orbit performance

Abstract 048: Identifying Genetic Modifiers for Cardiomyopathy via Mutagenesis Screening

Rationale: The generation of animal models for human cardiomyopathy creates opportunities to uncover mechanisms of diseases’ pathogenesis and to identify genes that modify the progression of pathogenesis. In contrast to candidate gene-based approaches, the phenotype-based forward genetic screening approach is less effectively employed in a vertebrate, mainly due to the prohibitively enormous colony management efforts. Objective: To identify genetic modifiers of cardiomyopathy through developing an unbiased forward genetic approach in the vertebrate Danio rerio. Methods and Results: Using an expression-based insertional mutagenesis screening strategy, we identified 49 Zebrafish Insertional Cardiac (ZIC) mutants from a collection of ~300 gene break-transposon (GBT) lines. By applying doxorubicin (DOX) stress to these heterozygous ZIC mutants, we initially identified four GBT lines that either enhanced or suppressed DOX-induced cardiomyopathy phenotypes. Here, we focus on the GBT0411 line which significantly enhances DOX-induced cardiomyopathy phenotypes. We cloned the gene and identified a single transposon insertion that disrupts the long nuclei isoform of dnajb6b in this GBT0411 mutant. Consistent with its cardiomyopathy modifier function, we detected a predominant expression of dnajb6b in the heart. While mutations affecting the cytoplasmic functions of DNAJB6 were recently reported to cause limb-girdle muscular dystrophy type 1D, our study suggested that the impaired balance between Dnajb6b long (nuclei) and short (cytoplasmic) isoform accounted for the cardiomyopathy modifier effect. Conclusions: Our results demonstrated the feasibility of identifying genetic modifiers of cardiomyopathy using a forward genetic approach in a vertebrate. Specifically, our data implicate DNAJB6 as a new genetic risk factor for DOX-induced cardiomyopathy. Without any presumption, this forward genetic strategy opens the door to systematically identify genetic factors that modify the progression of cardiomyopathy, which will facilitate the practice of personalized medicine and the development of novel therapies. </jats:p

Quantifying Cardiac Functions in Embryonic and Adult Zebrafish

Zebrafish embryos have been extensively used to study heart development and cardiac function, mainly due to the unique embryology and genetics of this model organism. Since most human heart disease occurs during adulthood, adult zebrafish models of heart disease are being created to dissect mechanisms of the disease and discover novel therapies. However, due to its small heart size, the use of cardiac functional assays in the adult zebrafish has been limited. To address this bottleneck, the transparent fish line casper;Tg(cmlc2:nuDsRed) that has a red fluorescent heart can be used to document beating hearts in vivo and to quantify cardiac functions in adult zebrafish. Here, we describe our methods for quantifying shortening fraction and heart rate in embryonic zebrafish, as well as in the juvenile and adult casper;Tg(cmlc2:nuDsRed) fish. In addition, we describe the red blood cell flow rate assay that can be used to reflect cardiac function indirectly in zebrafish at any stage

Weak signal detection for visible light communication in the pulse and transition regimes of an operational PMT detector via an SVM-based learning method

Photo-multiplier tube can be adopted for optical signal detection under weak signal and ambient light intensity, where the signals can be classified into three regimes, discrete-pulse regime, continuous waveform regime and the transition regime between the discrete-photon and continuous waveform regimes. While Poisson and Gaussian distributions can well characterize the discrete-photon and continuous waveform regimes, respectively, a statistical characterization and the related signal detection in the transition regime are difficult. In this work, we resort to a learning approach for the signal characterization and detection under pulse and transition regimes. We propose a support vector machine (SVM)-based approach for signal detection, which extracts eight key features on the received signal. We optimize the hyper-parameters to improve the SVM detection performance. The proposed SVM-based approach is experimentally evaluated under different symbol and sampling rates, and outperforms that of various statistics-based comparison benchmarks.</jats:p