Insect oviposition plasticity in response to host availability: the case of the tephritid fruit fly Bactrocera dorsalis

1. Insect oviposition behaviour is ecologically and physiologically plastic. For tephritid fruit flies, Bactrocera dorsalis Hendel, host availability varies spatially and temporally. Females are expected to adopt adaptive oviposition strategies to maximise lifetime reproductive fitness, including survival. Bactrocera dorsalis oviposition tactics in response to different host availabilities were investigated. 2. This study includes three treatments: (i) variable host densities (host density varied according to a fixed cycle from day to day over values of 1, 5, 10 and 20 hosts per cage), (ii) a fixed high host density (20 hosts per cage), and (iii) a fixed low host density (1 host per cage). 3. Daily egg‐laying number per female over the course of 27 days was entirely independent of host density and highly dependent on female age. As host availability increased, females accepted significantly more hosts, generally laid small egg clutches, and more broadly distributed the eggs. 4. Tephritid fruit flies adaptively adjusted egg clutches in ways that reflected the variability of host availability. Egg‐ and time‐limitation constraints appeared to drive these adjustments. Female egg maturation was triggered by oviposition activity and reflected marked lifetime trade‐offs. Such strategies involved specific time schedules for egg laying. 5.This study defined the oviposition plasticity of the tephritid fruit fly. These results have general implications for the behavioural ecology of insect herbivores and parasitoids.     

Quenched coumarin derivatives as fluorescence lifetime phantoms for NADH and FAD

Two-photon fluorescence lifetime imaging is a versatile laboratory technique in the field of biophotonics and its importance is also growing in the field of in vivo diagnostics for medical purposes. After years of experience in dermatology, endoscopic implementations of the technique are now posing new technical challenges. To develop, test, and compare instrumental solutions for this purpose suitable reference samples have been devised and tested. These reference samples can serve as reliable NADH- and FAD-mimicking optical phantoms for 2-photon fluorescence lifetime imaging, as they can be prepared relatively easily with reproducible and stable characteristics for this quite relevant diagnostic technique. The reference samples (mixtures of coumarin 1 and coumarin 6 in ethanol with suitable amounts of 4-hydroxy-TEMPO) have been tuned to exhibit spectral and temporal fluorescence characteristics very similar to those of NADH and FAD, the two molecules most frequently utilized to characterize cell metabolism.     

Mesoscopic fluorescence lifetime imaging: Fundamental principles,clinical applications and future directions

Fluorescence lifetime imaging (FLIm) is an optical spectroscopic imaging technique capable of real-time assessments of tissue properties in clinical settings. Label-free FLIm is sensitive to changes in tissue structure and biochemistry resulting from pathological conditions, thus providing optical contrast to identify and monitor the progression of disease. Technical and methodological advances over the last two decades have enabled the development of FLIm instrumentation for real-time, in situ, mesoscopic imaging compatible with standard clinical workflows. Herein, we review the fundamental working principles of mesoscopic FLIm, discuss the technical characteristics of current clinical FLIm instrumentation, highlight the most commonly used analytical methods to interpret fluorescence lifetime data and discuss the recent applications of FLIm in surgical oncology and cardiovascular diagnostics. Finally, we conclude with an outlook on the future directions of clinical FLIm.     

Intraoperative detection of IDH-mutant glioma using fluorescence lifetime imaging

Identifying isocitrate dehydrogenase (IDH)-mutation and glioma subtype during surgery instead of days later can aid in modifying tumor resection strategies for better survival outcomes. We report intraoperative identification of IDH-mutant glioma (N = 12 patients) with a clinically compatible fluorescence lifetime imaging (FLIm) device (excitation: 355 nm; emission spectral bands: 390/40 nm, 470/28 nm, 542/50 nm). The fluorescence-derived parameters were analyzed to study the optical contrast between IDH-mutant tumors and surrounding brain tissue. IDH-mutant oligodendrogliomas exhibited shorter lifetimes (3.3 ± 0.1 ns) than IDH-mutant astrocytomas (4.1 ± 0.1 ns). Both IDH-mutant glioma subtypes had shorter lifetimes than white matter (4.6 ± 0.4 ns) but had comparable lifetimes to cortex. Lifetimes also increased with malignancy grade within IDH-mutant oligodendrogliomas (grade 2: 2.96 ± 0.08 ns, grade 3: 3.4 ± 0.3 ns) but not within IDH-mutant astrocytomas. The current results support the feasibility of FLIm as a surgical adjuvant for identifying IDH-mutant glioma tissue.     

Fluorescence lifetime and rotational correlation time of bovine serum albumin-sodium dodecyl sulfate complex labeled with 1-dimethylaminonaphthalene-5-sulfonyl chloride: Effect of disulfide bridges in the protein on these fluorescence parameters

A fluorescent dye, 1-dimethylaminonaphthalene-5-sulfonyl chloride, was used to label bovine serum albumin (BSA), intact and disulfide bridges-cleaved. The fluorescence lifetime and fluorescence anisotropy of the adducts in sodium dodecyl sulfate (SDS) solutions were studied by the nanosecond fluorescence depolarization method. The volume of equivalent sphere (V _e) was calculated to be 2.1×10^–19 cm³ for BSA with the intact disulfide bridges from the rotational correlation time. The value ofV _e was 4.4×10^–19 cm³ for the disulfide bridges-cleaved BSA. With an increase in SDS concentration, the rotational correlation time of the intact BSA became longer, while that of the disulfide bridges-cleaved BSA became shorter. This suggests that upon the binding of SDS, the total volume of the intact BSA increases while the expanded state of the protein, caused by the cleavage of the disulfide bridges, becomes compact.     

Metabolic transcriptomics dictate responses of cone photoreceptors to retinitis pigmentosa

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Cone photoreceptors transfer damaged mitochondria to Müller glia

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Global and Site-Specific Effect of Phosphorylation on Protein Turnover

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Larval population density affects female weight and fecundity in the dung beetle Aphodius ater

1. Competition for food at high densities during larval development leads to reduced adult weight in the northern temperate dung beetle Aphodius ater. 2. Analysis of female beetles caught in the field showed that numbers of eggs and total egg load per female were correlated positively with beetle size. 3. Female beetles reared at different population densities during larval development in the laboratory were analysed with regard to their lifetime fecundity and reproductive lifespan. 4. High population densities during development had a negative influence on the number of eggs per female and on reproductive lifespan. Lifetime fecundity was correlated positively with female weight. 5. It was concluded that competition during larval development in the first generation of offspring will result in a lower number of offspring in the second generation in Aphodius ater, and thereby reduce parental fitness.     

Phytotropin-induced root phototropism in maize

Phytotropins, even those not absorbing in the visible region of the spectrum, can induce a phototropic response in maize ( Zea mays L. cv. PX-75) roots when illuminated unilaterally with white light. The most active phytotropin, 2-(1-pyrenoyl) benzoic acid (PBA) can elicit a full response at 10 μ M , while the other active molecules, 2-carboxyphenyl-3-phenylpropane-1,3-dione (CPD), 2-carboxyphenyl-3-phenyl-1,2-pyrazole (CPP), 1-N-naphthylphthalamic acid (NPA) and erythrosin elicit a full response at 100 μ M . The less active phytotropins BBA and fluorescein give a reduced response. It is suggested that the observed effect cannot be explained solely on the basis of auxin transport inhibition. There is a photoreceptor in the extension zone of the root, which may be associated in some way with the receptor for NPA. The results are consistent with the proposal that the phototropic process may form part of the root gravitropic response mechanism.