Tamal Roy

Bio: Tamal Roy is an academic researcher from Leibniz Association. The author has contributed to research in topics: Medicine & Demography. The author has an hindex of 13, co-authored 31 publications receiving 496 citations. Previous affiliations of Tamal Roy include Arizona State University & Indian Institute of Science.

Zebrafish Social Behavior in the Wild.

Abstract: Wild zebrafish exhibit a wide range of behavior. We found abundant wild zebrafish in flowing rivers and still water, in large, tightly-knit groups of hundreds of individuals, as well as in small, loose shoals. In two still-water populations, zebrafish were quite small in body size, common, and in tight groups of up to 22 fish. As in earlier laboratory studies, these zebrafish exhibited very low levels of aggression. In slowly flowing water in central India, zebrafish were relatively rare and gathered in small shoals (4–12 fish), often with other small fish, such as Rasbora daniconius. These stream zebrafish were larger in body size (27 mm TL) and much more aggressive than those in still water. In a second river population with much faster flowing water, zebrafish were abundant and again relatively large (21 mm TL). These zebrafish occurred in very large (up to 300 individuals) and tightly-knit (nearest-neighbor distances up to 21 mm) groups that exhibited collective rheotaxis and almost no aggres...

Population, sex and body size: determinants of behavioural variations and behavioural correlations among wild zebrafish Danio rerio.

Abstract: This study (1) investigated variation among populations and the effects of sex and body size on boldness, activity and shoal-association tendency among wild zebrafish, and (2) tested for existence ...

Learning and Memory in Juvenile Zebrafish: What makes the Difference – Population or Rearing Environment?

Abstract: The ability to learn and remember about the surrounding environment is crucial for the survival of organisms in their natural habitats. Adults of numerous fish species have been shown to display sophisticated behaviour related to learning and memory. This study deals with testing learning abilities among juveniles (10 wks old) of zebrafish (Danio rerio) through a simple task of finding food. We compared the performance of juveniles from two populations, a wild collected from a natural habitat and an aquarium-bred purchased from a pet shop, reared in bare environment (lacking visual cues). Additionally, we also tested the effect of early habitat enrichment on the performance among juveniles of the aquarium-bred population. The experiments involved training fishes to solve a simple maze (with a food reward at the end) and testing their memory. Learning was measured based on the time taken to complete the task (performance time) of finding food in the maze-arena across repeated trials. Our results showed that juveniles from the two populations possessed significantly different learning abilities. There were population differences in exploratory tendency and time taken to accomplish the task. However, when memory was tested based on performance time between training and test day, individuals (from both populations) were found to be poor at memorizing learnt tasks. On the other hand, juveniles (belonging to aquarium-bred population) reared in spatially complex environments displayed higher rates of learning and were capable of remembering learnt tasks better than their counterparts from bare environments. This study thus demonstrates the importance of rearing conditions and natural ecology in ontogenetic development of learning and memory functions among zebrafish.

Life History Evolution

Abstract: Life history biology sits on the interface between genetics and ecology, and both have made important theoretical and empirical contributions to our understanding. However, the connections between the disciplines have not always been as close as they might have been and this book takes some useful steps towards remedying this. It gives an excellent review of life history theory, and integrates this well with results from the empirical literature. After an 11-page introduction, Roff sets out ‘a framework for analysis’ in which he covers the necessary elements of quantitative and population genetics. This includes clear definitions of fitness in a range of circumstances, from density independent populations in constant environments through to the more complex situations of density and frequency dependence and environments that are spatially or temporally stochastic. Trade-offs are then examined, including a valuable analysis of potential pitfalls in studying them and ways that these can be avoided. The author then deals in turn with evolution in constant environments; stochastic environments and ‘predictable environments’. The last of these covers situations where there is environmental variation, but at least some information is available to allow individuals to make an adaptive response. The final chapter identifies 20 topics for future study. Some will find the book too dominated by theory. Others (but probably not readers of Heredity!) will find it contains too much genetics. But Roff does an excellent job of making the theory accessible, covering the essential issues and pointing to original sources for the details. Theory is related to a significant number of empirical studies, although there is room for another book reviewing the empirical literature on life histories in detail, and Roff’s book would provide a robust skeleton on which to hang this. To make my own assessment, I examined in detail Roff’s discussion of the question of fitness measures for density dependent populations in stochastic environments – an area in which I have been involved. I could not fault him – all the key references were there and the issues were made very clear without the more esoteric mathematics. I also examined some areas that I was less familiar with, and again the text was clear and easy to read. My only real criticism of the book would be that its very long chapters (more than 130 pages in one case) makes it difficult to find things. It would have been simple to address this by including the section headings on the contents pages. A minor personal quibble would be that the book usually expresses problems in terms of the intrinsic rate of increase, r, and the characteristic (Lotka) equation. A matrix formulation is often more tractable and is easier to generalise to density dependent populations and stochastic environments, so expanding on the relationship between the two would have been useful. But overall this is an excellent book. It brings together the key theory in a single place. It gives an invaluable route into the literature, with a bibliography of 1600 or so items. These features, and its identification of topics that need further study should make an important contribution to moving the field forward.

Zebrafish: Housing and husbandry recommendations:

Abstract: This article provides recommendations for the care of laboratory zebrafish (Danio rerio) as part of the further implementation of Annex A to the European Convention on the protection of vertebrate animals used for experimental and other scientific purposes, EU Commission Recommendation 2007/526/EC and the fulfilment of Article 33 of EU Directive 2010/63, both concerning the housing and care of experimental animals. The recommendations provide guidance on best practices and ranges of husbandry parameters within which zebrafish welfare, as well as reproducibility of experimental procedures, are assured. Husbandry procedures found today in zebrafish facilities are numerous. While the vast majority of these practices are perfectly acceptable in terms of zebrafish physiology and welfare, the reproducibility of experimental results could be improved by further standardisation of husbandry procedures and exchange of husbandry information between laboratories. Standardisation protocols providing ranges of husbandry parameters are likely to be more successful and appropriate than the implementation of a set of fixed guidance values neglecting the empirically successful daily routines of many facilities and will better reflect the wide range of environmental parameters that characterise the natural habitats occupied by zebrafish. A joint working group on zebrafish housing and husbandry recommendations, with members of the European Society for Fish Models in Biology and Medicine (EUFishBioMed) and of the Federation of European Laboratory Animal Science Associations (FELASA) has been given a mandate to provide guidelines based on a FELASA list of parameters, 'Terms of Reference'.

Cr(salophen) Complex Catalyzed Cyclic Carbonate Synthesis at Ambient Temperature And Pressure

Abstract: The combination of a chromium(III) salophen bromide complex and tetrabutylammonium bromide is shown to catalyze the reaction between terminal epoxides and carbon dioxide at ambient temperature and 1 bar carbon dioxide pressure and between internal epoxides and carbon dioxide at 80 °C and 10 bar carbon dioxide pressure to form cyclic carbonates. The optimal conditions involve the use of 1.5–2.5 mol % of both the chromium(III) salophen bromide complex and tetrabutylammonium bromide and result in the formation of cyclic carbonates in 57–92% isolated yields after a reaction time of 24 h. Under these conditions, no polycarbonate formation is observed except when cyclohexene oxide is used as substrate. The reactions were found to proceed with retention of epoxide stereochemistry. A study of the reaction kinetics revealed that the chromium(III) complex and tetrabutylammonium bromide react together to form a six-coordinate anionic chromium complex which is the actual catalyst, and a catalytic cycle is proposed wh...

Zebrafish Behavior: Opportunities and Challenges

Abstract: A great challenge in neuroscience is understanding how activity in the brain gives rise to behavior. The zebrafish is an ideal vertebrate model to address this challenge, thanks to the capacity, at the larval stage, for precise behavioral measurements, genetic manipulations, and recording and manipulation of neural activity noninvasively and at single-neuron resolution throughout the whole brain. These techniques are being further developed for application in freely moving animals and juvenile stages to study more complex behaviors including learning, decision making, and social interactions. We review some of the approaches that have been used to study the behavior of zebrafish and point to opportunities and challenges that lie ahead.

Reusable N-Heterocyclic Carbene Complex Catalysts and Beyond: A Perspective on Recycling Strategies

Abstract: With the continuous development of N-heterocyclic carbene (NHC) chemistry during the past decade, NHC metal complexes have gained wide applications in the research field of organometallic catalysis. The recycling and reuse of NHC metal complexes, which have undergone continuous expansion and diversification, can enhance their catalytic performance, extend their range of application, and afford new routes to green chemistry. Taking NHC metal complex catalysts as the main topic, this review intends to present a comprehensive study of recycling strategies of organometallic catalysts. By an elaborative summarization and classification of recycling strategies, a clear picture of all available of recycling strategies for organometallic catalysts is presented and the advantages and disadvantages of various recycling strategies for specific reactions are discussed in detail. This review is written with the hope of serving as a modest spur to induce other scientists’ further contributions in the fields of catalyst...