Dead reckoning in a small mammal: the evaluation of distance

When hoarding food under infra-red light, golden hamsters Mesocricetus auratus W. return fairly directly from a feeding place to their nest site by evaluating and updating internal signals that they have generated during the previous outward journey to the feeding place. To test more specifically the animals' capacity to evaluate the linear components of the outward journey, the subjects were led from their (cone-shaped) nest to a feeding place along a detour which comprised either 2 (experiment 1) or 5 (experiment 2) segments; adjoining segments were at right angles to each other. In these conditions, the subjects remained significantly oriented towards the nest and therefore were capable of assessing translations as well as rotations during the outward journey. In experiment 3, the nest was removed after the hamsters had started the direct outward journey to the feeding place and the hamsters were rotated during the food uptake. The animals were no longer oriented towards the starting point of their journey, but nonetheless covered, along a fairly straight path, the correct homing distance, and then changed over to a circular search path. These results confirm that mammals can derive the linear components of an outward journey from self-generated signals and therefore are able to judge the homing distance without relying on cues from the environment. For a number of detour outward journeys, our data yield an unexpectedly good fit to Müller and Wehner's (1988) model of dead reckoning in ants. However, this is no longer the case when the outward journey contains an initial loop which brings the subject back to the starting point. These findings are discussed in terms of the biological significance and limitations of an approximate form of path integration.     

西方长寿与衰老研究史精要

长寿是一个美丽的梦想,衰老是一个神秘的谜团.旨在回顾西方文明从远古至20世纪初,从民间到学术界,探索长寿之路,破解衰老之谜,冥思苦想苦苦追寻的漫漫历程,并按历史的足迹,将这错综复杂的过程分为八个历史时期予以阐述.     

A journey from reductionist to systemic cell biology aboard the schooner Tara

In this essay I describe my personal journey from reductionist to systems cell biology and describe how this in turn led to a 3-year sea voyage to explore complex ocean communities. In describing this journey, I hope to convey some important principles that I gleaned along the way. I realized that cellular functions emerge from multiple molecular interactions and that new approaches borrowed from statistical physics are required to understand the emergence of such complex systems. Then I wondered how such interaction networks developed during evolution. Because life first evolved in the oceans, it became a natural thing to start looking at the small organisms that compose the plankton in the world's oceans, of which 98% are … individual cells-hence the Tara Oceans voyage, which finished on 31 March 2012 in Lorient, France, after a 60,000-mile around-the-world journey that collected more than 30,000 samples from 153 sampling stations.     

Garden ant homing behavior in a maze task based on local visual cues

Although it has been shown that visual cues play an essential role in navigation by the garden ant Lasius niger, no previous studies have addressed the way in which information from local visual cues is acquired and utilized in navigation. We found that in the absence of pheromone trails, ants whose homing motivation was triggered by feeding returned to the nest following local visual cues. In our experiments, the ants travelled through a maze to reach a feeder. They explored the maze and sometimes became trapped in its dead ends. We found that the ants more effectively used visual cues during their homeward journey if they experienced a dead end during their outward journey. This result suggested that the ants used the information acquired from visual cues during the outward journey to avoid a dead end on their return journey.     

Short-distance homing in the golden hamster after a passive outward journey

The golden hamster carries food back to its nest along a direct path. In a situation combining a passive outward journey with the elimination of visual and various other exteroceptive cues, the subjects continued to return to their nest site and were not influenced by alterations of the earth's magnetic field. Experiments in which the animals started their hoarding trips from a changing point of departure, or were transferred to an unfamiliar experimental space, suggest that they orientate by path integration and that they assess the angular, but not the linear component of a passive outward journey.     

The formation and function of the female reproductive tract in flowering plants

In angiosperms, sexual reproduction requires a sperm cell, contained within a pollen tube, to fertilize the egg cell. The pollen tubes are capable of growth but have a difficult journey, as egg cells are buried within the ovary of the carpel. Several tissues, known collectively as the reproductive tract, develop within the carpel to facilitate the journey of the pollen tube. The genes involved in the formation and function of the reproductive tract have largely remained a mystery but are crucial for successful fertilization. This review summarizes recent advances in our understanding of the genetic control of reproductive tract development.     

A journey through the microscopic ages of DNA replication

Scientific discoveries and technological advancements are inseparable but not always take place in a coherent chronological manner. In the next, we will provide a seemingly unconnected and serendipitous series of scientific facts that, in the whole, converged to unveil DNA and its duplication. We will not cover here the many and fundamental contributions from microbial genetics and in vitro biochemistry. Rather, in this journey, we will emphasize the interplay between microscopy development culminating on super resolution fluorescence microscopy (i.e., nanoscopy) and digital image analysis and its impact on our understanding of DNA duplication. We will interlace the journey with landmark concepts and experiments that have brought the cellular DNA replication field to its present state.     

Host factors exploited by retroviruses

Retroviruses make a long and complex journey from outside the cell to the nucleus in the early stages of infection, and then an equally long journey back out again in the late stages of infection. Ongoing efforts are identifying an enormous array of cellular proteins that are used by the viruses in the course of their travels. These host factors are potential new targets for therapeutic intervention.     

Modulation and genetic identification of the M channel

Potassium channels constitute a superfamily of the most diversified ion channels, acting in delicate and accurate ways to control or modify many physiological and pathological functions including membrane excitability, transmitter release, cell proliferation and cell degeneration. The M-type channel is a unique ligand-regulated and voltage-gated K(+) channel showing distinct physiological and pharmacological characteristics. This review will cover some important progress in the study of M channel modulation, particularly focusing on membrane transduction mechanisms. The K(+) channel genes corresponding to the M channel have been identified and will be reviewed in detail.It has been a long journey since the discovery of M current in 1980 to our present understanding of the mysterious mechanisms for M channel modulation; a journey which exemplifies tremendous achievements in ion channel research and exciting discoveries of elaborate modulatory systems linked to these channels. While substantial evidence has accumulated, challenging questions remain to be answered.     

Schistosomiasis mass drug administration in the Philippines: lessons learnt and the global implications

Schistosomiasis was first reported in the Philippines in 1906. A variety of treatments have been deployed to cure infection and to control the disease in the long-term. We discuss the journey to combat the disease in the Philippines and the lessons learnt which have implications for schistosomiasis control globally.     

The journey of the malaria parasite in the mosquito: hopes for the new century

In this review, Anil Ghosh, Marten Edwards and Marcelo Jacobs-Lorena follow the journey of the Plasmodium parasite in the mosquito vector. At each developmental step, they highlight some of the major unanswered questions currently challenging cell and molecular biologists. A more thorough understanding of Plasmodium-mosquito interactions might lead to the development of mosquitoes unable to support parasite development.     

How desert ants cope with enforced detours on their way home

Summary We ask whether desert ants (Cataglyphis fortis) perform path integration on their homeward as well as on their outward journey. If path integration does occur on the return journey, then, after an enforced detour, the ant's trajectory should point directly at its nest. To test whether this is so, ants were trained to forage at a spot 25 m from their nest. As an ant began its return journey to the nest, it was caught and transported to a test area where it was released either 2 m or 12 m from a wide barrier which obstructed its homeward path. The direction of the ants' trajectory after detouring around the barrier corresponded closely to that predicted on the assumption that the home vector is accurately updated during the detour.     

Time Making and Place Making: A Journey of Immigration from Ethiopia to Israel

ABSTRACT

Anthropological studies of immigration usually focus on the immigrants’ country of origin or their destination. The present ethnographic study is a claim that the immigration experience must be examined as part of a journey and movement. The study was designed to show how the immigration process of Zera Beita Israel (Feres Mura) from Ethiopia to Israel is constructed on a process of journey and dialogue among the various stations. The two main aspects of the journey are place making – constructing a place in the unique context of immigration, and time making – creating being-time and meta-time, both unique to immigration. Each of the places affects the immigration process and is affected by this dynamic, nonlinear process. The combined concepts of place making and immigration time help explain the complexity of immigration.     

Journeying Between Desire and Anthropology: A Story in Suspense

Anthropology is a discipline based on the motif of the journey and ‘the myth of the eternal return’. This is the journey out to the ‘other’in order to return to constitute ‘self, and this movement is a movement of desire. The desire is for wholeness, for self‐presence, for a unified self. It is a desire for origins. And this desire is evident in anthropological practices as it is in myths and fairytales—all tell stories that speak of the desire for a separate, an original, self. Yet ‘the myth of the eternal return’reveals that the enactment of the story is itself originating. The origin is not a thing to be hunted down and appropriated—it is no thing. Like the archetypes which flow through stories, it is alive in the telling. The story I tell in this paper is about my own desires. It speaks of the desire to undergo the rite of passage of anthropology, and of how this journey was interrupted by the anthropologist who always journeys before me. And yet. it is through the inextricable relations with the writings of the “other‘ anthropologist that alluring moments of different desiring are fleetingly revealed. In the end. my relations with anthropology tell of a paradox: of the desire for a transcendental journey in order to constitute self and the seductive desire for immersion—to lose self, the story remains in suspense.     

The journey of Diagnostic Pathology in 2009, perspectives for 2010

Editorial: The journey of Diagnostic Pathology in 2009, perspectives for 2010     

Virus trafficking - learning from single-virus tracking

What could be a better way to study virus trafficking than 'miniaturizing oneself' and 'taking a ride with the virus particle' on its journey into the cell? Single-virus tracking in living cells potentially provides us with the means to visualize the virus journey. This approach allows us to follow the fate of individual virus particles and monitor dynamic interactions between viruses and cellular structures, revealing previously unobservable infection steps. The entry, trafficking and egress mechanisms of various animal viruses have been elucidated using this method. The combination of single-virus trafficking with systems approaches and state-of-the-art imaging technologies should prove exciting in the future.     

Going with the flow: a brief history of the study of the honeybee’s navigational ‘odometer’

Honeybees navigate to a food source using a sky-based compass to determine their travel direction, and an odometer to register how far they have travelled. The past 20 years have seen a renewed interest in understanding the nature of the odometer. Early work, pioneered by von Frisch and colleagues, hypothesized that travel distance is measured in terms of the energy that is consumed during the journey. More recent studies suggest that visual cues play a role as well. Specifically, bees appear to gauge travel distance by sensing the extent to which the image of the environment moves in the eye during the journey from the hive to the food source. Most of the evidence indicates that travel distance is measured during the outbound journey. Accumulation of odometric errors is restricted by resetting the odometer every time a prominent landmark is passed. When making detours around large obstacles, the odometer registers the total distance of the path that is flown to the destination, and not the “bee-line” distance. Finally, recent studies are revealing that bees can perform odometry in three dimensions.