Like mother, like daughter: How caterpillars pass down food preferences to their offspring

NUS researchers found that a ‘blood transfusion’ could perform this function

Peer-Reviewed Publication

NATIONAL UNIVERSITY OF SINGAPORE

 

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SCIENTISTS FROM THE NATIONAL UNIVERSITY OF SINGAPORE CONDUCTED SMELL TESTS WITH THE CATERPILLARS OF THE SQUINTING BUSH BROWN BUTTERFLY, BICYCLUS ANYNANA, AND FOUND THAT CATERPILLARS’ FOOD PREFERENCES ARE DETERMINED BY FACTORS, OR SUBSTANCES, PRESENT IN THEIR BLOOD AND THESE PREFERENCES COULD BE PASSED ON TO OFFSPRING THROUGH THE BLOODSTREAM.

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CREDIT: ASSOCIATE PROFESSOR WILLIAM PIEL, YALE-NUS COLLEGE

Many caterpillars are known for their specific food preferences, which they bring with them when they morph into butterflies. For instance, the monarch butterfly only feeds on milkweed plants, while the Lime butterfly feeds on lime leaves. Despite deriving from a common ancestral species, these unique diet preferences are a point of interest for researchers at the National University of Singapore (NUS).

In an earlier study by researchers at the Department of Biological Sciences under the NUS Faculty of Science, they demonstrated that when caterpillars fed on leaves outside of their usual diet, they would prefer the smell of that type of plant after a few days. Remarkably, these caterpillars also passed on the acquired smell preference to their offspring.

Such a phenomenon is also seen in nature when caterpillars find themselves on a new food plant when the female butterfly lays eggs on the wrong plant by mistake. The new plant is edible but has a new smell, the caterpillars will learn to prefer this new smell and pass this preference on to their offspring. This type of inheritance may facilitate host switching and ultimately the formation of new species, each with their own food preferences.

“Since new food preferences develop in the brain of caterpillars, it was unclear how such preferences were inherited by their offspring,” explained Professor Antónia Monteiro, who led the research team.

Dr. V. Gowri, the PhD graduate who is first author of the study said, “Offspring develop from the fusion of two cells (an egg and a sperm) produced in the gonads of each parent, which are located far from the brain. It was unclear how a smell preference was communicated to these cells.”

To discover the factors that influence this adaptive behaviour, the research team conducted experiments and showed that the blood of the caterpillar, called haemolymph, which bathes both the brain and the reproductive organs, contains factors that promote the inheritance of the new smell preference.

The NUS team published their findings in the scientific journal Biology Letters on 15 May 2024.

The catepillar’s smell test

A caterpillar’s blood can mediate the transport of factors from the brain to the gonads, impacting smell preferences in the next generation. Alternatively, it could transport these factors from the food to the brain of the embryo in the next generation, if included in the sperm or egg cells that create that embryo.

To test if the blood of caterpillars contained such factors, the newly hatched caterpillars were fed either the plants containing the new smell or a control plant. Some catepillar’s blood was then collected from their body once they matured. The collected blood was injected into catepillars that did not consume either type of food.

From this experiment, the researchers observed that the catepillars that received the blood from the control-fed catepillars stuck to their usual menu. By contrast, those that received blood from catepillars fed with food containing the new smell started to lean towards this change in diet. Most interestingly, so did their offspring, born many days later. 

“This was very surprising to us, as this experiment shows that learning a preference towards a smell can occur without the need for the smell to enter the caterpillar’s body via the antennae, as suggested in textbooks”, said Prof Monteiro.

These experiments suggest a possible mechanism that could help caterpillars switch their food preferences over the course of evolution. The researchers hope to further explore the mechanism of smell preference inheritance and isolate the specific factors being inherited from one generation to the next.

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JOURNAL

Biology Letters

DOI

10.1098/rsbl.2023.0595 

ARTICLE TITLE

Haemolymph transfusions transfer heritable learned novel odour preferences to naive larvae of Bicyclus anynana butterflies

 

How our brain decodes other people’s gaze

A UNIGE team has succeeded in determining the exact moment when the brain detects another person’s gaze direction.

UNIVERSITÉ DE GENÈVE

The gaze plays a central role in everyday social interactions. Our capacity for instant communication relies on the brain’s ability to detect and interpret the direction of others’ gaze. How does our brain detect gaze direction, and what factors influence the process? In a recent study published in the journal NeuroImage, a team from the University of Geneva (UNIGE) succeeded in determining with unprecedented precision the exact moment at which the direction of gaze is detected. These findings significantly enhance our understanding of autism spectrum disorders and could offer therapeutic prospects for people affected by Alzheimer’s disease. 

Human faces are the most common and consistent visual stimuli that we encounter from the second we are born. Our brain has developed the expertise to memorize and recognize faces, as well as to interpret messages they convey. For instance, the direct eye gaze signals a desire to engage in social interaction, while avoiding eye contact conveys the opposite message. But how rapidly can our brain comprehend the gaze of others? This topic has been extensively researched. However, existing publications predominantly focus on studying the eye region in isolation, neglecting other factors like head orientation.

Cerebral analysis of gaze

A team from UNIGE presented to study participants the 3D avatars, each featuring different head and gaze directions. In the first task, volunteers were asked to indicate the orientation of the head, while in the second task, they had to identify the direction of the eyes. By analysing the brain activity using an electroencephalogram, the research team has discovered that these two processes can be reliably decoded independently of each other.

‘‘The experiment also demonstrates a certain hierarchy in the processing of these two information. The brain first perceives the more global visual cues, i.e. the orientation of the head, from 20 milliseconds onwards, before focusing on the more local information, i.e. the eyes, from 140 milliseconds onwards. This hierarchical organisation then allows for integration of eye region and head orientation information, to ensure the accurate and effective judgement of gaze direction,’’ explains Domilė Tautvydaitė, a postdoctoral fellow and associate researcher at the UNIGE, Faculty of Psychology and Educational Sciences, and the study’s first author.

The study also demonstrates that the decoding of gaze direction was significantly more accurate when participants were specifically asked to pay attention to the gaze of the presented faces. This means that the task context influences the perception and understanding of the gaze. ‘‘In everyday life, these results show that when people are actively engaged in a ‘social mode’, they are better and faster at recognizing the intentions of other people,’’ explains Nicolas Burra, senior lecturer at the Faculty of Psychology and Educational Sciences and director of the Experimental Social Cognition Laboratory (ESClab) at UNIGE, who led this research.

A cutting-edge method

The method used provides extremely accurate results for these two mechanisms. By integrating the analysis of neural activity using electroencephalography (EEG) with machine-learning techniques, the research team could predict the decoding of gaze and head direction even before the participants were aware of it. ‘‘This method represents a significant technical innovation in the field, allowing for a much more precise analysis than it was previously attainable,’’ adds Nicolas Burra.

In people with autism spectrum disorders, the decoding of this information may be impaired, and the avoidance of eye contact may be preferred. This is also the case for Alzheimer’s disease, where during disease’s evolution, memory difficulties impoverish the person’s relationships with others and often lead to social withdrawal. It is therefore essential to understand the neural mechanisms in detecting the gaze direction.

The study results and the method used make a concrete contribution to the early diagnosis of autism spectrum disorders in children. Concerning Alzheimer’s disease, one of the most striking symptoms as the disease progresses is the inability to recognise faces, even those of family members. This study therefore paves the way for a better understanding of the neural mechanisms linked to reduced social interaction and memory for faces- a subject currently being studied by Dr Tautvydaitė at McGill University in Canada. The UNIGE’s ESClab laboratory research will continue in this field by analysing these processes during real-life social interactions.

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JOURNAL

NeuroImage

DOI

10.1016/j.neuroimage.2024.120659 

METHOD OF RESEARCH

News article

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The Timing of Gaze Direction Perception: ERP Decoding and Task Modulation

 

First-principles investigations of the polysomatism of antigorite under pressure

Peer-Reviewed Publication

EHIME UNIVERSITY

 

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THE CRYSTAL STRUCTURE OF ANTIGORITE WITH M=17. THE NUMBER OF TETRAHEDRA WITHIN ONE WAVELENGTH ALONG THE A-AXIS REPRESENTS THE M-VALUE. ORANGE: MG, BLUE: SI, RED: O, PINK: H

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CREDIT: JUN TSUCHIYA, EHIME UNIVERSITY

Antigorite is a type of serpentine, which is the most abundant hydrated mineral on the Earth. It is widely believed that this mineral is the main carrier of water deep into the Earth in subducting oceanic plates. It has a wavy structure along the a-axis, and in nature, several polysomes with different m-values (m=13-24) have been identified (polysomatism). The m-value is defined as the number of tetrahedra contained in one wavelength, and is controlled by the difference in length between the octahedral layer and the tetrahedral layer (Figure1). This length is mainly determined by the size of the MgO6 octahedra and SiO4 tetrahedra, and is therefore expected to vary as a function of pressure and temperature. However, it is not well understood how the m-value of antigorite changes under the high pressure and temperature conditions in the Earth.

In this study, we used the first-principles method to calculate the free energy (enthalpy) of antigorites with different m-values (m=14-19) under pressure, and compared the stability of antigorites with different m-values. As a result, it was found that the m-value of the most stable antigorite gradually decreases. In other words, antigorite gradually dehydrates as pressure increases, changing into a structure with a shorter wavelength.

This suggests that the structure of antigorite in the oceanic lithosphere may gradually evolve into a polysome with a smaller m-value that differs from the antigorite observed under ambient pressure or near-surface pressure conditions (i.e. m=17) (Figure2). Such changes in m-values are accompanied by minor dehydration reactions. Changes in the amount of water in rocks and minerals due to the polysomatism of antigorite in subduction zones may affect the distribution of intermediate-depth earthquakes, such as those observed in the double seismic zone.

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JOURNAL

Journal of Geophysical Research Solid Earth

DOI

10.1029/2023JB028060 

The present results indicate that the m-value of antigorite tends to decrease under high pressure. Therefore, the decrease in the m-value of antigorite is expected as the depth increases in subduction zones.

CREDIT

Jun Tsuchiya, Ehime University

 

Clever pupils don’t need to attend academically selective schools to thrive, study finds

TAYLOR & FRANCIS GROUP

Findings published in a new peer-reviewed paper in the British Journal of Educational Studies challenges the idea that academically selective schools are necessary for clever pupils to achieve good outcomes.

Selective schools are government-funded schools that enrol only the highest performing students. Pupils take a standardized entrance exam, from which the best-scoring are enrolled.

Some argue that selective schools are necessary for bright pupils to reach their full academic potential. Selective schools can outperform or perform just as well as elite schools in final year exams, but without the high fees charged to parents. Hence, selective schools can offer a means for children from low socioeconomic backgrounds to receive a first-class education.

However, others argue that selective schools disproportionately benefit high socioeconomic children whose parents can afford private tutoring to prepare them for the entrance exams.

“Studies show that parents wish to enrol their children into selective schools, because they believe it will increase the chances of their children getting into a prestigious university, and securing a well-paid and high-status job,” says Melissa Tham, a research fellow at the Mitchell Institute at Victoria University, Melbourne, Australia.

To find out whether there are benefits associated with selective schools, Tham and her colleagues Shuyan Huo, and Andrew Wade tracked almost 3000 pupils from the Longitudinal Surveys of Australian Youth (LSAY), a nationally representative survey program that follows young Australians over an 11-year period. The survey started when respondents were aged 15 in 2009.

As expected, the selective schools featured in the study had a higher proportion of academically high-achieving students, as measured by mathematics and reading scores.

However, at ages 19 and 25 there was little difference between the educational and employment outcomes of children who attended selective schools versus non-selective schools. For example, the study found that while 81% of selective school students went on to secure a job or university place at 19 compared to 77.6% of pupils from non-selective schools, this difference disappeared when the students were matched on key characteristics, including socioeconomic background, gender, and geographical location.

At age 25, all outcomes between selective and non-selective school students were not significant, except general life satisfaction. Attending a selective school increased a student’s general life satisfaction score by just 0.19 points. Meanwhile, students who attended non-selective school were just as likely to go on to study at university or secure a job as their peers who attended selective schools.

“These very modest findings indicate that attending an academically selective school does not appear to pay off in large benefits for individuals,” says Andrew Wade, co-author of the study.

“We argue that academically selective schools in the government sector therefore contradicts the principles of inclusive and equitable education which underpin Australia’s school system.”

According to the authors, the findings suggest that more research is needed to determine whether selective schools offer any benefit to academically able students.

“Rather than tweak some aspects of the enrolment processes, we see greater value in conducting a thorough and critical examination of fully and partially selective schools, and scaling back selectivity if the supposed benefits are not found,” says Huo.

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JOURNAL

British Journal of Educational Studies

DOI

10.1080/00071005.2024.2365189 

ARTICLE TITLE

Does School Academic Selectivity Pay Off? The Education, Employment and Life Satisfaction Outcomes of Australian Students

ARTICLE PUBLICATION DATE

4-Jul-2024

 

Desert-loving fungi and lichens pose deadly threat to 5,000-year-old rock art

Famous petroglyphs in the Negev desert are at risk of destruction from biological processes

FRONTIERS

 

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NEGEV PETROGLYPHS OF ANIMALS

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CREDIT: LAURA RABBACHIN, INTK, ACADEMY OF FINE ARTS, VIENNA

The Negev desert of southern Israel is renowned for its unique rock art. Since at least the third millennium BCE, the hunters, shepherds, and merchants who roamed the Negev have left thousands of carvings (‘petroglyphs’) on the rocks. These figures are mostly cut into ‘desert varnish’: a thin black coating on limestone rock, which forms naturally. Many represent animals such as ibexes, goats, horses, donkeys, and domestic camels, but abstract forms also occur.

Now, a study published in Frontiers in Fungal Biology has revealed that the petroglyphs are home to a community of uncommon specialist fungi and lichens. Unfortunately, these species may pose a serious threat to the rock art in the long term.

"We show that these fungi and lichens could significantly contribute to the gradual erosion and damage of the petroglyphs,” said Laura Rabbachin, a PhD student at the Academy of Fine Arts Vienna in Austria, and the study’s first author.

"They are able to secrete different types of acids that can dissolve the limestone in which the petroglyphs are carved. In addition, the fungi can penetrate and grow within the stone grains, causing an additional mechanical damage.”

Extreme conditions

Rabbachin and colleagues took samples from a petroglyph site in the central-western highlands of the Negev. Here, an average of just 87mm rain falls per year, and temperatures on rock surfaces can soar up to 56.3 °C in summer. The researchers scraped samples from desert varnish next to petroglyphs, from rocks without desert varnish, and from soil near the sampled rocks. They also left petri dishes open near the rocks to capture airborne spores.

The authors identified collected fungi and lichens with two complementary methods. First, they repeatedly cultured fungal material or spores from rocks or soil on plates with one of two different growth media, until they obtained pure isolates for DNA barcoding. Second, they directly performed DNA sequencing of fungal material present in rock or soil samples, without culturing them first. The latter method can detect strains that don’t grow in culture.

Few but destructive species on petroglyphs

Both methods showed that the diversity and abundance of species on rocks bearing petroglyphs was low in comparison with the soil, which suggests that few species are able to withstand the local extremes of drought and temperature.

DNA barcoding of cultured isolates revealed that the petroglyphs harbor multiple species of fungi within the genera Alternaria, Cladosporium, and Coniosporium, while direct sequencing further detected multiple species in the genera Vermiconidia, Knufia, Phaeotheca, and Devriesia. All except Alternaria and Cladosporium are so-called microcolonial fungi, known to thrive in hot and cold deserts around the world. Also abundant were lichens in the genus Flavoplaca.

“Microcolonial fungi are considered highly dangerous for stone artifacts. For example, they have been implicated as a probable cause of the deterioration of stone cultural heritage in the Mediterranean,” said Rabbachin.

“Lichens are also well known to cause rocks to deteriorate and thus to be a potential threat to stone cultural heritage.”

In the surrounding soil and air, the researchers mainly found different, cosmopolitan fungi, but which are known to be able to survive harsh desert conditions through the production of drought-resistant spores.

Documenting threatened rock art is a necessity

Can anything be done to protect the petroglyphs from the slow but destructive work of the observed microcolonial fungi and lichens? This is unlikely, cautioned the authors.

“These natural weathering processes cannot be stopped, but their speed of the weathering process depends heavily on whether and how the climate will change in the future. What we can do is to monitor the microbial communities over time and most importantly, document these valuable works of art in detail,” said Rabbachin’s academic supervisor Prof Katja Sterflinger, the study’s senior author.

Petroglyph showing human figure

Negev petroglyphs showing abstract forms

The landscape around the petroglyphs in the Negev desert

Fungus culture: Alternaria sp. NS4

CREDIT

Laura Rabbachin, INTK, Academy of Fine Arts, Vienna

JOURNAL

Frontiers in Fungal Biology

DOI

10.3389/ffunb.2024.1400380 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Diversity of fungi associated to petroglyph sites in the Negev desert, Israel, and their potential role in bioweathering

ARTICLE PUBLICATION DATE

5-Jul-2024

 

How listening for the right buzz keeps mosquitoes from mating with the wrong species

INSTITUTE OF TRANSFORMATIVE BIO-MOLECULES (ITBM), NAGOYA UNIVERSITY

 

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DIFFERENCES IN MALE AEDES AEGYPTI AND AEDES ALBOPICTUS HEARING SYSTEMS FACILITATE RECOGNITION OF CONSPECIFIC FEMALE FLIGHT TONES

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CREDIT: ISSEY TAKAHASHI

Researchers from Nagoya University in Japan have uncovered how the yellow fever mosquito and Asian tiger mosquito distinguish their own species from others. Males from these species listen for the specific frequencies of sound made by the flapping wings of females and use these sounds to select their own species. Their findings, published in iScience, have implications for developing innovative mosquito control strategies using artificial flight sounds.

The primary vectors for potentially deadly diseases including dengue fever and Zika fever are the yellow fever mosquito (Aedes aegypti) and Asian tiger mosquito (Aedes albopictus), which can transmit the viruses when they drink a blood meal.

“In the past few decades, the territories of the two types of mosquitos have increasingly overlapped,” said Dr. Matthew Su, joint corresponding author of the study. “Mainly at dusk, male Aedes mosquitoes form a swarm, a large group of flying males waiting for fertile females to fly in. When a female enters the group, the male uses his excellent hearing to hear her wing sound, approach her, and attempt to mate. But females of other species could enter the group too, so we became interested in how males avoid mating with the wrong species.”

The research team installed microphones in mosquito breeding cages to measure the frequencies of wingbeats of males and females and compared them between species. They discovered that both male and female Asian tiger mosquitoes had higher wing sound frequencies than yellow fever mosquitoes. 

They theorized that this difference explained how mosquitoes avoid mating with the wrong species. When they created synthetic female wing sounds and played them back to male mosquitoes, they noticed that male Asian tiger mosquitoes consistently responded to higher frequencies of sound than yellow fever mosquito males. 

“We believe the males have optimized the vibratory properties of their ‘ears’ to match the frequencies of females of the same species,” Professor Azusa Kamikouchi, the joint corresponding author, said. “This suggests that males are finely tuned to the specific wingbeat frequencies produced by females of their species.”

“Mosquito mating depends on male hearing of female sounds,” Su added. “Even though the difference in female sounds may sound small at 40 Hz, for mosquitoes—and humans in fact—this gap is huge. They modulate their hearing function via signals sent from their brains to their ears to listen for the right frequency. Humans actually do something similar to help tune out background noise to sleep or hear a friends’ voice in a noisy bar.”

When mosquito populations reach undesirably high levels, traps are used to control them. Oviposition traps work by attracting females to lay eggs and then killing them. Attractants are often used to lure female mosquitoes to the traps, but these new findings suggest that by adding flight sounds, males could also be trapped.

“I could see our research being used to combine oviposition and sound traps,” Su said. “Oviposition traps exist, but they mostly catch females, so we thought why not capture males at the same time? It’s good to plan ahead for potential outbreaks especially as the effects of climate change are increasing the number of people affected by mosquitoes.” 

The researchers stress that although combined oviposition and sound traps could be used to prevent mosquitoes from reproducing and eliminate them, this would not be a desirable outcome. Mosquitoes have important environmental roles as pollinators for plants and food for amphibians, which would be disrupted by their removal from the ecosystem. Instead, they hope to use trapping to control populations in the event of a population explosion, something which risks an increase in transmission of mosquito-borne diseases.

“Elimination may not be a good idea because we don’t know the effects on the ecosystem. Instead, we feel that limited biocontrol is better,” Dr. Su explained. “Ultimately, we will have to live together with mosquitoes, ideally separately. Therefore, we have to understand them and drive numbers down to levels where diseases are less likely to be transmitted.” 

 

Written by Matthew COSLETT. Science writer at Nagoya University International Communications office.

 

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About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).
See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI
Main WPI program site:  www.jsps.go.jp/english/e-toplevel

 

About the Institute of Transformative Bio-Molecules (WPI-ITbM) 
The Institute of Transformative Bio-Molecules (WPI-ITbM) at Nagoya University in Japan is committed to advance the integration of synthetic chemistry, plant/animal biology and theoretical science, all of which are traditionally strong fields in the university. The aim of ITbM is to develop transformative bio-molecules, innovative functional molecules capable of bringing about fundamental change to biological science and technology. Research at ITbM is carried out in a “Mix-Lab” style, where international young researchers from various fields work together side-by-side in the same lab, enabling interdisciplinary interaction. Through these endeavors, ITbM will create “transformative bio-molecules” that will dramatically change the way of research in chemistry, biology and other related fields to solve urgent problems, such as environmental issues, food production and medical technology that have a significant impact on the society. 

ITbM website: http://www.itbm.nagoya-u.ac.jp/

 

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JOURNAL

iScience

DOI

10.1016/j.isci.2024.110264 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Differences in male Aedes aegypti and Aedes albopictus hearing systems facilitate recognition of conspecific female flight tones

 

New probe reveals water-ice microstructures

UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA

 

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THE RAMAN SPECTROSCOPY AND CRYOSEM IMAGES OF THE ADI AQUEOUS SYSTEM.

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CREDIT: IMAGE BY PROF. ZHANG GUOQING’S TEAM

Ice is believed to have played a crucial role in the emergence of life. One reason is that organic molecules can be excluded into the gaps between the crystal lattice by orderly arranged water molecules, leading to the concentration of organic compounds. However, current methods for studying organic molecules in ice, such as Raman and infrared spectroscopy, mainly limited to absorption-based spectroscopic techniques, restricting measurement sensitivity.

A research team led by Prof. ZHANG Guoqing, Prof. LIU Shiyong, Prof. ZHOU Xiaoguo and Researcher ZHANG Xuepeng from the University of Science and Technology of China (USTC) developed a water-ice microstructures detection method using organic phosphorescent probes and phosphorescence spectroscopy. Their works were published in Angewandte Chemie.

The team proposed an emission-based method to study organic molecules in water ice. They used the hydration state of a phosphorescent probe, acridinium iodide (ADI), to indicate the microstructural changes of water ice (i.e., crystalline vs. glassy). The microstructures of water ice can be significantly dictated by a trace amount of water-soluble organic molecules. Specifically, if water ice maintains amorphous at low temperatures, the AD+ cation and I- anion of the ADI probe will be separated by bound water molecules, exhibiting long-lived phosphorescence and a visible greenish yellow afterglow. While in ordered crystalline ice, ADI probe molecules aggregate, inducing short-lived red phosphorescence through the heavy atom effect of iodine.

The emission spectra revealed distinct spectroscopic changes in aqueous solution of ADI upon the addition of ethylene glycol (EG) small molecules and monodispersed EG polymers (PDI=1). The addition of trace amounts of EG (0.1%) leads to the emergence of the fluorescence band around 480 nm, accompanied by more intense phosphorescence band with well-resolved vibronic progressions at 555, 598 and 648 nm. The spectral results indicated that the addition of EG led to the transformation of ADI molecules in water ice from undissolved aggregates to dissolved ion states.

To corroborate the conclusions of phosphorescence spectroscopy, low-temperature scanning electron microscopy (Cryo-SEM) images showed that the addition of trace EG into the water ice containing ADI resulted in local areas with porous microstructures. Meanwhile, low-temperature Raman (LT-Raman) spectra confirmed that the addition of trace EG was sufficient to cause a shift in the O-H vibration of water ice from a low-frequency crystalline state to a high-frequency glassy state.

This study discovered that adding trace amounts of small or large molecular organics to water can significantly inhibit the crystalline order of water ice by using more convenient and sensitive phosphorescence spectroscopy. Moreover, the phosphorescence spectroscopy can also reveal morphological differences in water-ice microstructures when trace organics with different structures and same concentration are added into water, which is consistent with Raman spectroscopy and scanning electron microscopy, providing a new technical mean for studying water-ice-organics interactions at lower concentration and wider temperature range.

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JOURNAL

Angewandte Chemie

DOI

10.1002/anie.202405314 

ARTICLE TITLE

Water-Ice Microstructures and Hydration States of Acridinium Iodide Studied by Phosphorescence Spectroscopy