Editor's note: Starting National Science Day 2018, The Life of Science and Firstpost bring you a series profiling Indian women in Science. The challenges in Indian scientific life are many — more so for women taking up this path. This series honours those who beat the odds and serve as inspirations for the next generation of Indian science — a generation that is slowly and surely on its way to becoming gender equal.
By Shraddha Naik
Sreelaja Nair | Embryologist | Tata Institute of Fundamental Research (TIFR), Mumbai
Triveni Menon, Janakraj Bhattrai and I stepped out of the air-conditioned Nair Lab in the Department of Biological Sciences into a sunny and humid day at Colaba. As we moved away from the old seaside building that housed the labs, I smelled a rat — literally. We were near the 'rodent facility', I was told by the young researchers, before being directed into a smaller facility adjacent to it — Sreelaja Nair’s 'fish facility'. This is where we would go, to watch zebrafish mating!
Having been smitten by zebrafish since her early PhD days at the University of California at Irvine, USA, Sreelaja considered the zebrafish model critical to answering her scientific questions. However, when she arrived at TIFR in July 2012, there was no such ‘fish facility’ nearby. So first, she had to build her own lab.
After working for her graduate and postdoctoral training in fully-functioning labs at UC-Irvine and the University of Wisconsin-Madison respectively, she was taken aback when she stared at the derelict room assigned to her. It was not just her, but the famous Mumbai rains, too, that had found their way into the lab. “I had no office... my lab did not exist," she says, describing the situation she had encountered a month after she joined TIFR. Her requests to officials were cavalierly handled, and she was told that her space may be ready only by early 2013.
Tempers rose. She called for a meeting. “So it ended up being a roomful of middle-aged men and I in the basement of TIFR, where I gave them all a piece of my mind,” she said.
Her lab was up and running in November 2012 — a feat that she takes pride in. “It required every iota of my brain space and physical stamina, and I did no science during that time,” she recounted. She came exceedingly close to painting the walls herself!
After she set up her own personal lab, Sreelaja's next uphill task was to establish the 'fish facility'. It took two years to finally get water to start flowing through this specialised lab. From fishing for suitable land within the campus, to sourcing state-of-the-art equipment and getting all the basic hardware and functioning figured out, she managed it all.
It is common for newbie investigators to experience such rocky beginnings — the ‘gestation period’ as they call it, Sreelaja said. “You come prepared to get your science off the ground. But initially, you need to do the groundwork. Each of us has done it,” she said, very matter-of-factly.
As I stepped into the facility, I realised that I was in a very sophisticated aquarium, and all the instruments in there were crucial for doing the basic science Sreelaja and her team are interested in.
These photos give us a glimpse into her lab’s compelling science, mentoring principles and other activities.
The visuals that drew Sreelaja to developmental biology
Her team's work is concerned with the very initial moments of life, when organisms are only single-celled embryos. This single cell, in fact, contains all the information necessary to transform into a multicellular, multi-organ, three-dimensional individual. After an embryo is formed by the union of the sperm and egg, the period that follows is called ‘transcriptional quiescence’, when the embryo’s own DNA is quiet.
During this period, the mother’s RNA and proteins received by the embryo through her egg sustain it. The mother’s proteins decide when the embryo’s own DNA becomes active. If this activation does not occur at the right time, it drastically affects the position and size of body organs, leading to congenital defects that are often fatal. Her lab tries to pinpoint those proteins which are directly involved in this process. In this image, you can see a zebrafish embryo dividing ~ 90 mins after fertilisation. The coloured structures are proteins collectively called the mitotic spindle, which assists the embryo in its division.
Playing cupid in the world of zebrafish
Zebrafish (Danio rerio) is a tropical freshwater fish native to the Himalayan region. Since it is not ethical to study human embryos directly, Sreelaja uses zebrafish as a model organism to study early development. These fish share 70 percent of their genes with humans.
In the picture on the left, Triveni, a PhD student working the lab holds up a tank to check if spawning (egg release) has occurred.
In the picture on the right, a fish couple are at play in a mating tank. Around 100 fertilised eggs can be collected from one couple, 30-60 minutes after the facility lights turn on at 9:00 am. Interestingly, mating in zebrafish is dependent on cycles of light and dark.
Nothing fishy about this facility
Triveni and Janak, in the picture on the left, are two researchers in the Nair Lab, who spend half their work hours in the fish facility, acquiring, handling and working on fish embryos.
The fish facility, featured in the picture on the right, contains rows and rows of fish tanks. Since it is easy to get confused and mix different fish lines (they all look the same), the tanks are appropriately labelled and handled with utmost care. Because it is an aquatic system, Sreelaja installed a facility that recycles 90 percent of the water used; the remaining 10 percent contains nitrogenous waste products. “That 10 percent organic, good quality water could in principle be used to water plants at TIFR, ensuring water conservation,” she explained. It is an aspect she would later propose in the TIFR re-development plan.
Sperm meets the egg, but with Triveni’s approval
In the picture to the left, PhD student Triveni tracks the development of zebrafish embryos. To be in control of the timeline of the entire process, she performs in vitro fertilisation.
She first anaesthetises the male, collects its sperm which look like shimmering specks under the microscope, and suspends the sperm in saline (water with sodium chloride). Next, it’s the female's turn (above right, posing for the camera). She then anaesthetises the female and squeezes out a clump of her eggs. Finally, she introduces the sperm to the egg in water. And bang! Fertilisation!
She turns on a timer in a split second, as she collects a few embryos at set intervals post-fertilisation for microscopy and molecular analysis at various stages.
The fish embryos (below right) are suspended in an embryonic medium in petridishes. The blue tint indicates the presence of methylene blue, which acts as a fungicide. These dishes are placed in 280C incubators for as long as the experiment demands.
Poking at zebrafish embryos
Unlike Triveni, MSc student Janak uses naturally fertilised eggs for his research. The beauty of a fish embryo lies in the ease with which specific proteins can be added or removed and visualised. To do this, he performs embryo microinjections. He has already prepared a series of injection needles for this procedure. Although Janak feels conscious as I watch over him like a hawk (above left), his hours of practice hold him steady as he backloads the needle with the injection solution usually containing DNA or RNA.
(Above right) The needle up close with the solution near the tip, which has to be injected. It has been coloured with a red dye, rhodamine, for easy visibility.
(Below left) A microscopic view (image provided by Janak) of the embryos he plans to inject before they divide.
(Below right) He targets the needle at a specific region within the embryo with a tiny robotic device called a micromanipulator. He depresses a foot pedal and the needle delivers a calculated amount of the solution at optimal pressure.
“It’s not a career, it’s a lifestyle choice”
Mentoring forms a crucial part of Sreelaja’s training. She feels grateful for all her past research mentors, and tries to stitch together the best practices she has learnt to offer to her students. Her lab has regular meetings, where she encourages her students to present their opinions and ideas. Many times, these discussions flow into longer conversations in the evenings over tea at the cafeteria, as they ponder over science and life. She ensures her students annually attend three to four scientific conferences or meetings, and especially give talks to the larger scientific community. “It’s not a career, it’s a lifestyle choice," is the way she describes her philosophy of approaching science work, with the hope that they will understand one day.
Dancing her way through science
Science is difficult and researchers often beat themselves up after failed experiments, but Sreelaja has always known how to unwind. She is a trained Bharatanatyam dancer. During her postdoctoral fellowship at the University of Wisconsin-Madison, she used to travel 90 minutes to another city, Milwaukee, to dance every Sunday. “I would train for two hours, then for the remaining six hours or so, I would teach dance. After that, I would come back to the lab in Madison... I absolutely loved it! It was a good kind of exhaustion," she says, beaming. Today, she ensures her students are not stressed by taking them on outdoor rain walks or having them accompany her and her husband and biophysicist Roop Mallik on weekend treks.
Sreelaja insists that scientists share their work with the public. "People deserve to know where their tax money is going," she says. Recently, she delivered a talk at the bookstore Kitab Khana as part of Mumbai Local, a monthly gathering where artists or scientists are invited to talk about their work. Amazed at how curious people were, she also held a session at Prithvi Theatre in Mumbai, as part of Chai and Why, TIFR’s very own outreach program.
Read more from the Women in Science series here.
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Updated Date: Apr 23, 2018 18:22:20 IST