Insect trypanosomatids: the need to know more

Of ten recognized trypanosomatid genera, only two - pathogenic Trypanosoma and Leishmania - have been actively investigated for any length of time while the plant flagellates - Phytomonas - have recently begun to attract attention due to their role as agricultural parasites. The remaining genera that comprise parasites associated with insects have been largely neglected except for two or three containing popular isolates. This publication reviews current knowledge of trypanosomatids from insects.     

Fishery statistics: What we need to know

Abstract

A recent exchange of papers articulated the need for revision and extensions of the existing data set on the world's catch of ocean fish. The suggested revisions involve linking the existing Food and Agricultural Organization (FAO) geographical areas with currently defined extended economic zones (EEZs) and an improved ability to obtain data on specific key species offish that are important for conservation or commercial purposes or both. The suggested extensions involve the inclusion of economic data primarily on capital, labor, and fishing effort in the FAO data set. Given a consensus on the need for an improved data base, the next question is: Of the many options available, what statistics at what cost and for what set of end users should be prepared.     

Membrane fission by dynamin: what we know and what we need to know

The large GTPase dynamin is the first protein shown to catalyze membrane fission. Dynamin and its related proteins are essential to many cell functions, from endocytosis to organelle division and fusion, and it plays a critical role in many physiological functions such as synaptic transmission and muscle contraction. Research of the past three decades has focused on understanding how dynamin works. In this review, we present the basis for an emerging consensus on how dynamin functions. Three properties of dynamin are strongly supported by experimental data: first, dynamin oligomerizes into a helical polymer; second, dynamin oligomer constricts in the presence of GTP; and third, dynamin catalyzes membrane fission upon GTP hydrolysis. We present the two current models for fission, essentially diverging in how GTP energy is spent. We further discuss how future research might solve the remaining open questions presently under discussion.     

The detection of estrus in cattle raised under tropical conditions: what we know and what we need to know

Lack of accuracy in estrus detection in cattle is a major constraint affecting the implementation of techniques such as artificial insemination (AI) and embryo transfer (ET). For this reason clinicians have opted to pharmacologically manipulate the estrus cycle. The advantages and shortcomings of using this approach to improve the implementation of AI and ET are discussed in this review. Moreover, in order to highlight the reasons why estrus detection is difficult in cows kept at grazing in the tropics, this review underlines social and behavioral traits hindering the capacity of the casual observer to accurately identify cows in estrus.     

Breast cancer genetics: what we know and what we need

Breast cancer results from genetic and environmental factors leading to the accumulation of mutations in essential genes. Genetic predisposition may have a strong, almost singular effect, as with BRCA1 and BRCA2, or may represent the cumulative effects of multiple low-penetrance susceptibility alleles. Here we review high- and low-penetrance breast-cancer-susceptibility alleles and discuss ongoing efforts to identify additional susceptibility genes. Ultimately these discoveries will lead to individualized breast cancer risk assessment and a reduction in breast cancer incidence.     

Amphibian decline and extinction: what we know and what we need to learn

For over 350 million yr, thousands of amphibian species have lived on Earth. Since the 1980s, amphibians have been disappearing at an alarming rate, in many cases quite suddenly. What is causing these declines and extinctions? In the modern era (post 1500) there are 6 leading causes of biodiversity loss in general, and all of these acting alone or together are responsible for modern amphibian declines: commercial use; introduced/exotic species that compete with, prey on, and parasitize native frogs and salamanders; land use change; contaminants; climate change; and infectious disease. The first 3 causes are historical in the sense that they have been operating for hundreds of years, although the rate of change due to each accelerated greatly after about the mid-20th century. Contaminants, climate change, and emerging infectious diseases are modern causes suspected of being responsible for the so-called 'enigmatic decline' of amphibians in protected areas. Introduced/exotic pathogens, land use change, and infectious disease are the 3 causes with a clear role in amphibian decline as well as extinction; thus far, the other 3 causes are only implicated in decline and not extinction. The present work is a review of the 6 causes with a focus on pathogens and suggested areas where new research is needed. Batrachochytrium dendrobatidis (Bd) is a chytrid fungus that is an emerging infectious disease causing amphibian population decline and species extinction. Historically, pathogens have not been seen as a major cause of extinction, but Bd is an exception, which is why it is such an interesting, important pathogen to understand. The late 20th and early 21st century global biodiversity loss is characterized as a sixth extinction event. Amphibians are a striking example of these losses as they disappear at a rate that greatly exceeds historical levels. Consequently, modern amphibian decline and extinction is a lens through which we can view the larger story of biodiversity loss and its consequences.     

The conserved genome organisation of non-falciparum malaria species: the need to know more

The current knowledge on genomes of non-falciparum malaria species and the potential of model malaria parasites for functional analyses are reviewed and compared with those of the most pathogenic human parasite, Plasmodium falciparum. There are remarkable similarities in overall genome composition among the different species at the level of chromosome organisation and chromosome number, conserved order of individual genes, and even conserved functions of specific gene domains and regulatory control elements. With the initiative taken to sequence the genome of P. falciparum, a wealth of information is already becoming available to the scientific community. In order to exploit the biological information content of a complete genome sequence, simple storage of the bulk of sequence data will be inadequate. The requirement for functional analyses to determine the biological role of the open reading frames is commonly accepted and knowledge of the genomes of the animal model malaria species will facilitate these analyses. Detailed comparative genome information and sequencing of additional Plasmodium genomes will provide a deeper insight into the evolutionary history of the species, the biology of the parasite, and its interactions with the mammalian host and mosquito vector. Therefore, an extended and integrated approach will enhance our knowledge of malaria and will ultimately lead to a more rational approach that identifies and evaluates new targets for anti-malarial drug and vaccine development.     

The Drosophila circadian clock: what we know and what we don't know.

Circadian rhythms are regulated by endogenous body clocks, which are formed by rhythmic cycles of clock gene expression. Almost all reviews of the Drosophila circadian clock state that the intracellular oscillator is based on a simple negative feedback loop. However, not many 'simple' feedback loops in biology last for 24 h. Instead, the Drosophila clock is a series of precisely timed steps that are deliberately slow. In this paper, I will discuss the current model for how the Drosophila clock is regulated, and ask what questions remain to be answered.     

The hologenome concept: we need to incorporate function

Are we in the midst of a paradigm change in biology and have animals and plants lost their individuality, i.e., are even so-called ‘typical’ organisms no longer organisms in their own right? Is the study of the holobiont—host plus its symbiotic microorganisms—no longer optional, but rather an obligatory path that must be taken for a comprehensive understanding of the ecology and evolution of the individual components that make up a holobiont? Or are associated microbes merely a component of their host’s environment, and the holobiont concept is just a beautiful idea that does not add much or anything to our understanding of evolution? This article explores different aspects of the concept of the holobiont. We focus on the aspect of functional integration, a central holobiont property, which is only rarely considered thoroughly. We conclude that the holobiont comes in degrees, i.e., we regard the property of being a holobiont as a continuous trait that we term holobiontness, and that holobiontness is differentiated in several dimensions. Although the holobiont represents yet another level of selection (different from classical individual or group selection because it acts on a system that is composed of multiple species), it depends on the grade of functional integration whether or not the holobiont concept helps to cast light on the various degrees of interactions between symbiotic partners.