Whence meiosis?

Sexual reproduction predominates among eukaryotic organisms on our planet. While debate continues over why this should be so, burgeoning genomic and functional information now allows us to begin to think reasonably about some of the events that may have occurred to make sex possible in the first place.     

Whence the red panda?

The evolutionary history of the red panda (Ailurus fulgens) plays a pivotal role in the higher-level phylogeny of the "bear-like" arctoid carnivoran mammals. Characters from morphology and molecules have provided inconsistent evidence for placement of the red panda. Whereas it certainly is an arctoid, there has been major controversy about whether it should be placed with the bears (ursids), ursids plus pinnipeds (seals, sea lions, walrus), raccoons (procyonids), musteloids (raccoons plus weasels, skunks, otters, and badgers [mustelids]), or as a monotypic lineage of uncertain phylogenetic affinities. Nucleotide sequence data from three mitochondrial genes and one nuclear intron were analyzed, with more complete taxonomic sampling of relevant taxa (arctoids) than previously available in analyses of primary molecular data, to clarify the phylogenetic relationships of the red panda to other arctoid carnivorans. This study provides detailed phylogenetic analyses (both parsimony and maximum-likelihood) of primary character data for arctoid carnivorans, including bootstrap and decay indices for all arctoid nodes, and three statistical tests of alternative phylogenetic hypotheses for the placement of the red panda. Combined phylogenetic analyses reject the hypotheses that the red panda is most closely related to the bears (ursids) or to the raccoons (procyonids). Rather, evidence from nucleotide sequences strongly support placement of the red panda within a broad Musteloidea (sensu lato) clade, including three major lineages (the red panda, the skunks [mephitids], and a clearly monophyletic clade of procyonids plus mustelids [sensu stricto, excluding skunks]). Within the Musteloidea, interrelationships of the three major lineages are unclear and probably are best considered an unresolved trichotomy. These data provide compelling evidence for the relationships of the red panda and demonstrate that small taxonomic sample sizes can result in misleading or possibly erroneous (based on prior modeling, as well as conflict between the results of our analyses of less and more complete data sets) conclusions about phylogenetic relationships and taxonomy.     

Conditional strategies in territorial defense: do Carolina wrens play tit-for-tat?

Neighboring territorial animals are viewed primarily as intenserivals, but there are also opportunities for cooperation amongcompetitors. Many animals respond less aggressively towardneighbors than to strangers. This phenomenon, termed the "dearenemy" effect, should be stable only when the reduced aggressionis reciprocal. Territory owners should use conditional strategiesin territorial defense, showing reduced aggression toward neighbors who cooperate by respecting territorial boundaries but increasingaggression toward invading neighbors. In this study I examinedthe response of territory owners to playbacks of neighborsat shared boundaries before and after intrusions by that neighboror by strangers. Results showed that territory owners did notincrease their aggression toward defecting neighbors but did increase their aggression toward neighbors after a simulatedintrusion by a stranger. This surprising result might reflectthe long-term relationship between neighboring Carolina wrensand the threat posed by rare intruding strangers.     

Whence comes Trypanosoma lewisi antigen which induces ablastic antibody: Studies in the occult?

I propose that trypanosomes have three antigen compartments: the intracellular, plasma membrane, and extracellular compartments. The intracellular antigens are released when trypanosomes lyse; the plasma membrane antigens are the structural or transport components of the plasma membrane and the adhering surface coat; the extracellular antigens are secreted by the trypanosomes. I further suggest that ablastinogen, the Trypanosoma lewisi antigen which induces ablastic antibody, is a plasma membrane antigen, and that the T. lewisi trypanocidal antigens are in the surface coat. The T. lewisi exoantigens described by D'Alesandro (1972) are, as he stated, different from ablastinogen and trypanocidal antigens. I suggest that the exoantigens are secreted extracellular antigens. Data from the literature are presented to support the hypothesis, and an experimental protocol to test the hypothesis is outlined.     

Alterations?in?White?Matter?Microstructure?as?Vulnerability?Factors?and?Acquired?Signs?of?Traffic?Accident-Induced?PTSD

It remains unclear whether white matter (WM) changes found in post-traumatic stress disorder (PTSD) patients are stress-induced or precursors for vulnerability. The current study aimed to identify susceptibility factors relating to the development of PTSD and to examine the ability of these factors to predict the course of longitudinal PTSD. Sixty two victims who had experienced traffic accidents underwent diffusion tensor imaging using a 3.0T MRI system within 2 days after their accidents. Of these, 21 were diagnosed with PTSD at 1 or 6 months using the Clinician-Administered Ptsd Scale (CAPS). Then, 11 trauma-exposed victims with PTSD underwent the second MRI scan. Compared with the victims without PTSD, the victims with PTSD showed decreased fractional anisotropy (FA) in WM of the anterior cingulate cortex, ventromedial prefrontal cortex (vmPFC), temporal lobes and midbrain, and increased mean diffusivity (MD) in the vmPFC within 2 days after the traumatic event. Importantly, decreased FA of the vmPFC in the acute phase predicted greater future CAPS scores. In addition, we found decreased FA in the insula in the follow-up scan in the victims with PTSD, which correlated with the decreased FA of the vmPFC in their baseline scan. These results suggested that the WM might have changed within 2 days after the traumatic event in the individuals who would later develop PTSD. Furthermore, decreased FA of the vmPFC could be a possible vulnerability marker predicting future development of PTSD and may provide an outcome prediction of the acquired signs.     

Serological?identification and molecular?characterization?of?B?(A)?02?subtype?in?patients?and blood donors from?Eastern?China

This study was designed to identify the rare type ABO blood groups, B(A) 02, from Eastern China. Three samples with discordant serological results during routine blood type identification and four samples from one sample’ family were selected. All of them were detected by serological method. The exon 6 and 7 of the ABO genes were amplified by PCR and sequenced. They were typed as AsubB by serology and as BO by genotype. In AsubB samples, nt 700C>G mutation was detected in B gene, which was previously defined as B(A)02 alleles. In these seven samples, six showed B(A)02/O01 and one showed B(A)02/O02.B(A)02 allele was found to be more common in this study than B(A)04 which is considered to be more frequent than B(A)02. The careful identification of rare blood types is important for the safety of clinical blood transfusion.     

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Hvetef?r?dlingen f?r Svealand

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