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.     

Adaptation to environmental changes: communities need more time than species

Effects of environmental changes on communities and on species have been studied with two different types of animals: mammals and conodonts. This analysis was conducted on mammals from the ’Ubeidiya Sequence (Israel) dated to the Lower Pleistocene, and on conodonts from the quarry of Coumiac (France) dated to the Frasnian/Famennian boundary (Devonian). The main result of the analysis is that an ecological event can be subdivided. First of all there is a change in the environment that corresponds to a physical signal, the species react to this change, and afterwards the communities respond. Thus, a delay in time can be observed between the reaction of the species and the reaction of the community to an environmental signal.     

The genome of the malaria parasite

The genome of the human malaria parasite Plasmodium falciparum is being sequenced by an international consortium. Two of the parasite's 14 chromosomes have been completed and several other chromosomes are nearly finished. Even at this early stage of the project, analysis of the genome sequence has provided promising new leads for drug and vaccine development.     

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.     

Intraspecies variation in bacterial genomes: the need for a species genome concept

Bacterial populations are clonal. Their evolution involves not only divergence between orthologous genes but also gain of genes from other clones or species, which has only recently been widely appreciated through macrorestriction mapping, genomic subtraction and complete genome sequencing. Genes can also be lost in response to selection or by random mutation after becoming redundant. The bacterial genome is a dynamic structure and intraspecies variation needs to be included in genome analysis if we are to gain insight into the full species genome.     

Grief and bereavement: what psychiatrists need to know

This review covers four areas of clinical importance to practicing psychiatrists: a) symptoms and course of uncomplicated (normal) grief; b) differential diagnosis, clinical characteristics and treatment of complicated grief; c) differential diagnosis, clinical characteristics and treatment of grief-related major depression; and d) psychiatrists’ reactions to patient suicides. Psychiatrists often are ill prepared to identify complicated grief and grief-related major depression, and may not always be trained to identify or provide the most appropriate course of treatment. Both conditions overlap with symptoms found in ordinary, uncomplicated grief, and often are written off as “normal” with the faulty assumption that time, strength of character and the natural support system will heal. While uncomplicated grief may be extremely painful, disruptive and consuming, it is usually tolerable and self-limited and does not require formal treatment. However, both complicated grief and grief-related major depression can be persistent and gravely disabling, can dramatically interfere with function and quality of life, and may even be life threatening in the absence of treatment; and both usually respond to targeted psychiatric interventions. In addition, patient suicide has been reported as one of the most frequent and stressful crises experienced by health providers, and psychiatrists are not immune to complicated grief or grief-related depression when they, themselves, become survivors. Thus, it is essential for psychiatrists to recognize their own vulnerabilities to the personal assaults that often accompany such losses, not only for their own mental health and well-being, but also to provide the most sensitive and enlightened care to their patients.     

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.