18S rRNA data indicate that Aschelminthes are polyphyletic in origin and consist of at least three distinct clades

The Aschelminthes is a collection of at least eight animal phyla, historically grouped together because the absence of a true body cavity was perceived as a pseudocoelom. Analyses of 18S rRNA sequences from six Aschelminth phyla (including four previously unpublished sequences) support polyphyly for the Aschelminthes. At least three distinct groups of Aschelminthes were detected: the Priapulida among the protostomes, the Rotifera-Acanthocephala as a sister group to the protostomes, and the Nematoda as a basal group to the triploblastic Eumetazoa.      

Plant polyphenols—secondary metabolism and chemical defence: Some observations

Secondary metabolism and theories of plant-animal co-evolution are briefly discussed. Current ideas concerning the role of polyphenols as mediators of a general form of chemical defence in plants are outlined. Studies are described of the association of a group of biosynthetically inter-related polyphenols based on gallic acid and D-glucose with the protein bovine serum albumin. The results are interpreted in terms of structure-activity relationships in protein-polyphenol complexation and are used to comment on the co-evolution theory and the position of plant polyphenols in higher plant secondary metabolism and defence.     

Interspecific and intraspecific comparisons of the period locus in the Drosophila willistoni sibling species

The period (per) locus has received much attention in molecular evolution studies because it is one of the best studied "behavioral genes" and because it offers insight into the evolution of repetitive sequences. We studied most of the coding region of per in Drosophila willistoni and confirmed previously observed patterns of conservation and divergence among distantly related species. Five regions are so highly diverged that they cannot be aligned, whereas a region encompassing the PAS domain is very conserved. Structural and nucleotide polymorphism patterns in the willistoni group are not the same as those observed in previously studied species. We sequenced the region homologous to the highly polymorphic threonine-glycine repeat of D. melanogaster in multiple strains of D. willistoni, as well as in other members of willistoni group, and found an unusual amount of conservation in this region. However, the next nonconserved region downstream in the sequence is quite variable and polymorphic for the number of repeated glycines. The glycine codon usage is significantly different in this glycine repeat as compared to other parts of the gene. We were able to plot the directionality of change in the glycine repeat region onto a phylogeny and find that the addition of glycines is the general trend with the diversification of the willistoni group.      

Lymphocyte suppression associated with alpha globulin. Changes in cellular immunity

Sensitization of guinea pigs to 2,4-dinitrofluorobenzene is accompanied by increases in alpha globulins determined electrophoretically. During sensitization, lymphocyte responses were measured in vitro by mitogen induced ³H-thymidine uptake in whole blood cultures and in vivo by dermal skin reactivity. Following 5 days of dinitrofluorobenzene sensitization alpha globulins were elevated and lymphocyte transformation to phytohemagglutinin, pokeweed mitogen, and concanavalin A was significantly suppressed. When the alpha globulins returned to normal levels following sensitization, lymphocyte responses returned to pretreatment values. Antigen induced lymphocyte responsiveness was also suppressed concomitant with elevations in alpha globulins. Tuberculin sensitive guinea pigs responded poorly to PPD in vitro and in vivo during DNFB sensitization. It is suggested that increases in alpha globulins detected during the development of cellular immunity are associated with immunosuppression.     

Ferritin as an iron-storage protein: mechanisms of iron uptake

The major physiological role of the ubiquitous protein ferritin is to store iron, which it does as a mineral core within a protein shell. Using evidence from a variety of sources we suggest that this versatile protein responds in its mechanism of iron uptake to changes in environmental conditions.     

Differential expression patterns of phospholipase D isoforms 1 and 2 in the mammalian brain and retina

Phosphatidic acid is a key signaling molecule heavily implicated in exocytosis due to its protein-binding partners and propensity to induce negative membrane curvature. One phosphatidic acid-producing enzyme, phospholipase D (PLD), has also been implicated in neurotransmission. Unfortunately, due to the unreliability of reagents, there has been confusion in the literature regarding the expression of PLD isoforms in the mammalian brain which has hampered our understanding of their functional roles in neurons. To address this, we generated epitope-tagged PLD1 and PLD2 knockin mice using CRISPR/Cas9. Using these mice, we show that PLD1 and PLD2 are both localized at synapses by adulthood, with PLD2 expression being considerably higher in glial cells and PLD1 expression predominating in neurons. Interestingly, we observed that only PLD1 is expressed in the mouse retina, where it is found in the synaptic plexiform layers. These data provide critical information regarding the localization and potential role of PLDs in the central nervous system.