Identified taste bud cell proliferation in the perihatching chick [published erratum appears in Chem Senses 1998 Aug;23(4):459]

Developing taste buds in the anterior mandibular floor of perihatching chicks were studied by high voltage electron microscopic autoradiography in order to identify proliferating gemmal cell types. Montaged profiles of 29 taste buds in five cases euthanized between embryonic day 21 and posthatching day 2 were analyzed after a single [3H]thymidine injection administered on embryonic day 16, 17 or 18. Results showed that dark cells comprised 55% of identified (n = 900 cells) and 62% of labeled (n = 568 cells) gemmal cells as compared with light, intermediate, basal or perigemmal bud cells. Dark cells had both a greater (P < 0.05) number of labeled cells and a greater amount of label (grains/nucleus) than the other four bud cell types, irrespective of injection day. The nuclear area (micron 2) of dark cells was not significantly larger (P > 0.05) than that of the other gemmal cell types and therefore cannot account for the greater amount for label in the dark cells. Interestingly, only dark cells showed a positive correlation (P < 0.003) between amount of label and nuclear area. Results suggest that, during the perihatching period of robust cell proliferation, dividing dark cells may give rise primarily, but not exclusively, to dark cell progeny.      

Characterization of the expressed immunoglobulin IGHV repertoire in the New World marmoset Callithrix jacchus

The common marmoset (Callithrix jacchus jacchus) is a member of the Callithrichinae, a family of outbred New World primates with limited MHC polymorphisms and a propensity to develop spontaneous or experimentally induced autoimmunity. C. jacchus marmosets are susceptible to experimental allergic encephalomyelitis (EAE), and spontaneously develop autoimmune colitis and thyroiditis. Such disease models approximate the complexity of human autoimmune disorders, and allow an investigation of the respective roles of T-cell and antibody responses to self-antigens in outbred species. A key issue for further definition of the pathogenic antibody responses in human autoimmunity is to understand the diversity of the immunoglobulin repertoire in primate models. Here, we characterized the expressed immunoglobulin IGHV repertoire of the C. jacchus marmoset. Six IGHV subgroups were identified which show a high degree of sequence similarity to their human IGHV counterparts (IGHV1, IGHV3, IGHV4, IGHV5, IGHV6, and IGHV7). As in the expressed human IGHV repertoire, the framework regions are more conserved when compared to the complementarity-determining regions (CDRs), with the greatest degree of variability located in CDR3. Predicted structural features are highly conserved between C. jacchus and human IGHV. This information now provides a framework for studies of the antigen-specific repertoire of pathogenic antibodies in EAE and other immune-mediated diseases.     

The ecological integrity of the Lower Olifants River,Limpopo province,South Africa: 2009–2015 – Part A: Olifants River main stem

The major rivers of the South African ‘Lowveld’ (low-latitude savanna) suffer numerous impacts from upstream economic activities. Whereas monitoring these rivers is required to detect biodiversity losses, record pollution events and devise mitigation strategies, current monitoring programmes are inadequate. In 2009, the South African Earth Observation Network initiated an intensive long-term research programme on the Lowveld reaches of the Olifants River. Physico-chemical parameters, aquatic macroinvertebrates and fish abundances were recorded at four Lowveld sites in the Olifants River. We review six years of this programme. The results suggest deterioration in the ecological condition of the Olifants River with no discernible improvement through protected areas. Trends could not be detected. The parameters measured, sampling methods and/or sampling frequency might be responsible for the limited trends observed, or alternatively the results simply reflect stable conditions despite on-going pollution. Real time monitoring and an expansion in the parameters monitored would add value to the monitoring programme.     

GluA1 trafficking and metabotropic NMDA: addressing results from other laboratories inconsistent with ours

We have previously shown that when over-expressed in neurons, green fluorescent protein (GFP) tagged GluA1 (GluA1-GFP) delivery into synapses is dependent on plasticity. A recent study suggests that GluA1 over-expression leads to its incorporation into the synapse, in the absence of additional long-term potentiation-like manipulations. It is possible that a GFP tag was responsible for the difference. Using rectification index as a measure of synaptic delivery of GluA1, we found no difference in the synaptic delivery of GluA1-GFP versus untagged GluA1. We recently published a study showing that while D-APV blocks NMDAr-dependent long-term depression (LTD), MK-801 and 7-chloro kynurenate (7CK) fail to block LTD. We propose a metabotropic function for the NMDA receptor in LTD induction. In contrast to our observations, recent unpublished data suggest that the above antagonists are equally effective in blocking LTD. We noticed different methodology in their study. Here, we show that their methodology has complex effects on synaptic transmission. Therefore, it is not possible to conclude that 7CK is effective in blocking LTD from their type of experiment.     

Cloning of an interleukin-4 inducible gene from cytotoxic T lymphocytes and its identification as a lipase

Interleukin-4 (IL-4) has been demonstrated to be an important lymphokine for the generation of cytotoxic T lymphocytes (CTLs). Here we describe an IL-4 inducible gene specifically expressed in CTLs. By sequence homology, this gene is likely to be the mouse homolog of pancreatic lipase. Oocyte translation of in vitro transcribed mRNA results in the expression of a protein with lipase activity, and Northern analysis of various tissues and a large panel of hematopoietic cell types demonstrates that this gene is expressed only in the pancreas and CTLs. Lysates of CTLs grown in IL-4, but not in IL-2, exhibit lipase activity. Furthermore, Northern analysis of CTLs grown in the presence of IL-4 for as little as 5 days demonstrates a marked induction of lipase mRNA, which correlates with enhanced cytolysis by these cells. These results suggest that this lipase may have an important role in CTL effector function.