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In memory of Nina Mikhailovna Litvinova - Trinity version - Science
On May 12, the bright Nina Mikhailovna Litvinova, who graced this earth, passed away. Nina was a zoologist by profession. However, her true calling was to help other people. I had the good fortune to know Nina solely from working together on expeditions - two to the Sea of Japan and one to the Barents Sea. In this note I will talk a little about Nina, her favorite brittle stars and, as popularly as I can, about the results we obtained. However, first I will quote a text written by human rights activist Tatyana Osipova-Kovalyova, from which I learned about Nina’s death:
Nina Litvinova, an ocean explorer and participant in the dissident movement, who did an incredible amount to support political prisoners in the 1960–1980s and in the 2000–2020s, has died. She worked at the Institute of Oceanology of the Russian Academy of Sciences, and devoted more than forty years of scientific work to brittle stars and other marine echinoderms. But she devoted even more years to helping people. Nina Mikhailovna Litvinova was born on August 9, 1945 into a family closely connected with Soviet political history. She was the granddaughter of Maxim Litvinov, the USSR People's Commissar for Foreign Affairs in the 1930s and ambassador to the United States during World War II, and the sister of Pavel Litvinov, a prominent Soviet dissident who took part in the August 25, 1968 demonstration against the entry of troops into Czechoslovakia.
Nina Litvinova herself did not strive for publicity and said that the fame of her surname rather weighed on her. At the same time, her family experience, memory of repression and social circle gradually drew her into the space of late Soviet resistance. She read and distributed samizdat, reprinted the Chronicle of Current Events, went to trials, went to visit her brother and other dissidents in exile, and carried letters, books and parcels.
“It seems to me that we lived with such common sympathy. Everyone helped each other,” Litvinova later recalled.
From the 1960s until the end of her life, Nina Litvinova helped political prisoners; for the last eight years, together with activists from Memorial*, she traveled to Petrozavodsk for the trials of historian Yuri Dmitriev, came to meetings on the cases of Oleg Orlov**, Zhenya Berkovich***, helped Olga Bendas a lot, but also helped many non-media and unknown political prisoners.
Nina Mikhailovna always remained in the shadow of her brother, grandfather, other relatives and famous dissidents. But it was precisely this quiet and almost imperceptible support of the persecuted that was her consciously chosen strategy. For Nina Litvinova, refusal to participate in official lies and everyday assistance to political prisoners existed as something natural and did not require glorification. Therefore, she almost always refused interviews and performances.
Nina Litvinova personified modest but unbending courage and nobility. She was always there where it hurt the most. The best memory will be the continuation of her deeds.
* The Supreme Court of the Russian Federation recognized the international public movement “Memorial” as an “extremist organization.”
** Included by the Ministry of Justice of the Russian Federation in the register of foreign agents.
*** Included by the Federal Service for Financial Monitoring in the list of persons and organizations involved in extremist activities and terrorism.
Long before meeting Nina Litvinova, I met her mother, Flora Pavlovna Yasinovskaya. This was in the 1950–1951 academic year, when I was a fourth-year student at the Department of Human and Animal Physiology, Faculty of Biology, Moscow State University. The course on the physiology of the cardiovascular system was taught to us by Mikhail Egorovich Udelnov, who was not only an associate professor of the department, but also the head of the laboratory at the Cardiological Institute of the Academy of Medical Sciences. Flora Yasinovskaya was an employee of his laboratory and came to listen to his course. One day we got into a conversation and liked each other. After that, we met many times, since I visited her more than once in her laboratory, where many of my friends worked, as well as at various reports and conferences. We always enjoyed these meetings. I knew that Flora had a son and a daughter, but I did not know them.
It was hard not to become friends with Nina. In my entire already very long life, I have rarely met such friendly, modest and likable people. (There are no words in my language to describe all of Nina’s human qualities.)
Briefly about brittle stars
As a zoologist, Nina studied brittle stars. When I tried to talk about this work to people who did not have a biological education, most of them did not know what brittle stars were, although everyone had heard about starfish. Brittle stars are their closest relatives. They are the most diverse class of echinoderms, with approximately 2,000 species. Unlike sea stars, which have thick, slightly bending rays, brittle stars have thin and flexible rays, consisting of many segments connected to each other. Brittle stars found in coastal waters of the former USSR typically have five rays (Fig. 1A). However, many-rayed brittle stars are found in tropical seas (Fig. 1B). Hence their name, which is translated from Greek as snaketails (ὄφις (ophis) - snake, οὐρά (oura) - tail). I suspect that the multi-rayed brittle stars could be a prototype of the Gorgon Medusa, the heroine of Greek mythology who had snakes writhing on her head instead of hair.
Study of the circadian rhythm in brittle stars
When we met Nina, she was a senior laboratory assistant at the Institute of Oceanology and, as I understand it, did not have much prospects for career growth. To move from laboratory assistant to researcher, Nina had to defend her Ph.D. thesis. To do this, a zoologist studying brittle stars had to at least find and describe in detail a new species. It is clear that all types of brittle stars living in the coastal waters of the USSR have already been described. It was possible to discover a new species only on expeditions to tropical seas. The Institute of Oceanology organized such expeditions, but they included visits to foreign ports, which means that strict questionnaire requirements were imposed on the participants. It is clear that Nina, Pavel Litvinov’s sister, was not one of these chosen ones. Therefore, she was forced to study the behavior of brittle stars [1]. We, as physiologists, enthusiastically offered our help to her. I will describe only some of the results obtained together with Nina.
Looking back, I think the most interesting results were related to the study of the circadian rhythm of brittle stars.
Serious study of circadian rhythms began in the first half of the 1970s. Before this, in the 1960s, it became clear that insects and vertebrates have endogenous circadian rhythms. In particular, it was shown that people in conditions of complete darkness for up to several weeks retain not only the usual circadian rhythm of sleep and wakefulness, but also such indicators as daily fluctuations in body temperature, urine and sweat secretion, etc. In the first half of the 1970s, experiments on mammals showed that the role of an internal clock in them is played by the suprachiasmatic nucleus of the hypothalamus, the work of which is determined by endogenous mechanisms: the neurons of the nucleus continue to generate a circadian rhythm after their isolation. The suprachiasmatic nucleus begins to function in the embryo, which proves the genetic nature of the circadian rhythm. These studies subsequently developed rapidly, and in 2017, the Nobel Prize was awarded for work devoted to the identification of genes and molecular mechanisms that determine circadian rhythms.
Before our work, almost no one had studied the daily activity of echinoderms. First of all, it was necessary to find out how brittle stars behave under normal conditions. To do this, 20–30 animals were placed in an aquarium, the bottom of which was covered with natural soil (sand and small stones). Every hour one of us had to count the number of brittle stars on the surface of the ground. We divided the day into five shifts: four five-hour shifts and one night shift - from 2 to 6 am. Night observations were carried out under red light, to which brittle stars are insensitive.
Here I again want to say a few words about Nina. Since I was the only “early person”, and the rest were “night owls,” I took over the morning duty from 6 to 11. Nina immediately stated that she would always work the night shift. This caused a protest among the men: they insisted on completely releasing her from night duty. After some debate, they barely overcame Nina’s resistance and agreed on equality.
Brittle stars turned out to be nocturnal animals 2 [2]. They crawled to the surface at approximately 8 pm and disappeared into the ground at 8 am (Fig. 2A, left). The greatest activity was observed around midnight, when over 50% of individuals were on the ground surface. During the entire daylight period (from 8 am to 8 pm), the activity of brittle stars was close to zero. Brittle stars have a pronounced negative phototaxis: when the aquarium was illuminated at night, they disappeared from the surface (Fig. 2A, right). Light-sensitive cells in brittle stars are distributed throughout the body. To answer the main question—about the existence of endogenous circadian activity in brittle stars—they were kept in complete darkness for seven days. Rice. 2B demonstrates the answer to this question - it turned out to be positive.
Wave-like movements of rays
In brittle stars located in shelter, one or several rays protrude above the ground surface and make wave-like movements towards the disk [3]. A technique for filming these movements was developed. Oscillations were carried out in the vertical plane with a frequency of 0.5–1 Hz. When a drop of ink was released at the end of the oscillating beam, it quickly moved towards the disk and after 5 s it ended up in the area of the mouth opening. The flow of water towards the disc may serve to transport nutrient particles to the mouth or to aerate the water in the disc area. To test the second assumption, 30 brittle stars were placed in an aquarium with soil and aerated water. Under these conditions, 5–10 rays oscillated. After a ten-hour cessation of aeration, the number of rays varied from 20 to 35. An hour after the resumption of aeration, the number of oscillating rays again decreased to 10–15. Thus, the oscillatory movements of the rays served to aerate the water in the disk area. The question of whether these movements also serve the function of transporting food particles remains open.
Locomotion of brittle stars
Unlike starfish, which move solely using their 3 ambulacral legs, brittle stars move primarily using rays that bend as a result of muscle contractions. There are three main types of movements: 1) the “breaststroke” method, when one beam (leading) is directed forward, two back, and two lateral ones are periodically brought forward and then, bending, move the disc and the remaining beams forward; 2) pull-up on the leading beam; 3) pushing with rear rays [4]. Each of these methods can be used either independently or in combination with others. Rice. 3 illustrates the movement of brittle stars using the breaststroke method. In Fig. 3A shows combined four consecutive frames (1–4), when the brittle star brings forward its lateral rays, and in Fig. 3B - five consecutive frames (4–8), when the backward-bending rays push the brittle star forward.
In addition to the rays, the locomotion of brittle stars involves ambulacral legs - thin tubes with a suction cup at the end located on the ventral surface of the disc and rays. The main property of the ambulacral legs is that when brittle stars move, they stick to the ground in the anterior position and come off in the extreme posterior position [4, 5]. As can be seen in Fig. 3A, during locomotion using the “breaststroke” method, during the extension of the lateral rays, the disk does not remain motionless, but moves forward. This movement is carried out due to the work of the ambulacral legs. These legs rarely play an independent role in the locomotion of brittle stars. This usually happens in cases where brittle stars crawl in the cracks between stones.
In this case, the ambulacral legs play an important role in movement carried out with the help of rays. In Fig. 3B shows that while the disc, anterior and posterior rays, as well as the proximal parts of the lateral rays move forward, the more distant (distal) sections of the lateral rays remain motionless. This is explained as follows. When the brittle star moves forward, due to the bending of the lateral rays, all the hind legs, with the exception of the distal parts of the lateral rays, which bend the least, move backward and come off the surface. The legs of the distal rays, which bend the least, move forward and are attached to the ground surface. Thus, they serve as a support for brittle stars to move forward. This interpretation of the coordinated work of the rays and ambulacral legs is confirmed by the fact that brittle stars can crawl not only along a horizontal surface, but also along the vertical wall of an aquarium.
The nervous system of the brittle star consists of five ganglia connected to each other, located at the base of each ray. In experiments with cutting connections between ganglia, it was shown that the coordinated work of the rays is carried out by the ganglion lying at the base of the leading ray [6]. When the brittle star changes direction, it does not turn its entire body. Instead, another ray becomes the leader, and the ganglion located at its base begins to coordinate the synchronous work of the two adjacent lateral rays.
Turning over the brittle star
The brittle star turned onto its back quickly restores its original position with the help of rays [7]. The movements of the rays when turning over are standard for all individuals. Therefore, they are largely determined by the genetic program. In this case, peripheral signals determine only which of the rays starts turning over. The turning over reaction could be caused by one of three factors: 1) data on the direction of gravity (if brittle stars had such receptors); 2) irritation of sensory receptors on the dorsal surface of the body; 3) lack of signals from receptors on the abdominal surface of the body. The third assumption has been shown to be correct. The turning over reaction is caused by the absence of signals from the receptors of the abdominal surface, more precisely, from the receptors of the ambulacral legs.
Dissertation defense
The material that Nina received before meeting us and in our joint work was more than enough to defend her Ph.D. dissertation. However, for defense it was necessary to pass three exams: in the specialty, a foreign language and philosophy (historical and dialectical materialism). If my memory serves me correctly, Nina passed the first two exams, and then announced that she would not defend her dissertation.
We were shocked: “Nina!!! What's happened? Why?" “I cannot take an exam on this false philosophy,” she answered.
No matter how much we persuaded her, we said that this was an empty formality, always very soft and friendly, Nina turned out to be unusually persistent. The matter ended with G.N. Orlovsky finding a teacher at the Department of Philosophy of the USSR Academy of Sciences who agreed for a rather large (for that time) sum of money to draw up documents for passing the exam. We helped Nina raise this money, and the issue was resolved. Nina successfully defended her dissertation.
* * *
After the defense, I almost never met with Nina. We found a good facility on the White Sea, and I was passionate about the new work. In 1991, I was invited to the University of California, San Diego. I don’t remember when I received an unexpected “hello” from Nina. On Popov Island, where we worked together, beautiful butterflies flew, and I collected a small collection, which was kept in cardboard boxes at home as a souvenir. When I left for America, I left these boxes with my employee. One day I received my butterflies, professionally packaged in wooden boxes, with a note that they had been made transportable at Nina’s request by her entomologist friends. Now these butterflies hang in front of me, and I remember Nina and the happy days of our relative youth.
Yuri Arshavsky, PhD, BioCircuits Institute,
University of California San Diego
PS I thank T. G. Delyagin and V. Ptushenko, who helped me find reprints of our joint articles with Nina Litvinova, and A. G. Feldman, who sent me the book by F. P. Yasinovskaya.
1. Litvinova N. M. Some data on the behavior of the brittle star Amphipholis Kochii Lütken / Proceedings of the Soviet-Japanese symposium on echinoderms and mollusks. - Vladivostok, 1974. pp. 99–100.
2. Arshavsky Yu. I., Kashin S. M., Litvinova N. M., Orlovsky G. N., Feldman A. G. Daily changes in the activity of the brittle star Amphipholis kochii Lütken (Ophiuroidea, Amphiuridae) // Zoological Journal. 1976. V. 15. No. 11. P. 1737–1739.
3. Arshavsky Yu. I., Kashin S. M., Litvinova N. M., Orlovsky G. N., Feldman A. G. Some behavioral features of the brittle star Amphipholis kochii (Ophiuroidea, Amphiuridae) // Zoological Journal. 1976. V. 15. No. 12. S. 1851–1861.
4. Arshavsky Yu. I., Kashin S. M., Litvinova N. M., Orlovsky G. N., Feldman A. G. Types of locomotion in brittle stars // Neurophysiology. 1976. V. 8. No. 5. pp. 521–528.
5. Arshavsky Yu. I., Kashin S. M., Litvinova N. M., Orlovsky G. N., Feldman A. G. Coordination of the movement of rays during brittle star locomotion // Neurophysiology. 1976. V. 8. No. 5. pp. 529–537.
6. Arshavsky Yu. I., Kashin S. M., Litvinova N. M., Orlovsky G. N., Feldman A. G. Coordination of the movement of the ambulacral legs and rays during locomotion // Neurophysiology. 1976. V. 8. No. 6. pp. 633–639.
7. Arshavsky Yu. I., Kashin S. M., Litvinova N. M., Orlovsky G. N., Feldman A. G. Turning over of the brittle star Amphipholis kochii // Journal of evolutionary biochemistry and physiology. 1977. V. 13. No. 1. pp. 39–43.
8. Litvinova (Yasinovskaya) F. P. Essays on past years. - M.: Links, 2008.
1 www.trv-science.ru/2017/10/nobelevskaya-nedelya
2 Authors of this and other articles are listed in alphabetical order. This mode was introduced by the founder of our laboratory, I.M. Gelfand, who said that people often quarrel over the order of authorship in articles. Therefore, to avoid misunderstandings, he suggested that in joint articles the authors should be mentioned in alphabetical order.
3 Echinoderms are characterized by a special ambulacral (hydraulic) system of movement and other functions - breathing, excretion, touch. – Approx. ed.