Age correlated changes in midgut protease activity of the honeybee,Apis mellifera (Hymenoptera: Apidae)

Summary Forager (older) worker honeybees typically have lower midgut activity levels of chymotrypsin and trypsin than do house (younger) worker honeybees. A relation between the age correlated enzymic change and an age correlated decrease in pollen consumption is not clearly demonstrable.     

Correlation between K1 and K2 in the fractional clearance of bromosulphthalein in cattle and sheep suffering from different hepatotoxic diseases

Zusammenfassung Ein direkter Zusammenhang zwischen der crsten Phase (K₁) und der zweiten Phase (K₂) der fraktionellen Senkung des Bromsulphthaleinspiegels hat sich an von hepatoxischcn Krankheiten befallenen Kühen und Schafen erwiesen. Es ist anzunehmen, dass die K₂-Werte empfindlichere Nachweise der Lebertätigkeit in diesen Tieren aufweisen als die K₁-Werte.     

Initial sequencing and analysis of the human genome

The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.     

Hsp90 binds CpG oligonucleotides directly: implications for hsp90 as a missing link in CpG signaling and recognition

CpG motifs originating from bacterial DNA (CpG DNA) can act as danger signals for the mammalian immune system. These CpG DNA motifs like many other pathogen-associated molecular patterns are believed to be recognized by a member of the toll-like receptor family, TLR-9. Here we show results suggesting that heat shock protein 90 (hsp90) is also implicated in the recognition of CpG DNA. Hsp90 was characterized as a binder to oligodeoxynucleotides (ODNs) containing CpG motifs (CpG ODNs) after several purification steps from crude protein extracts of peripheral blood mononuclear cells. This finding was further supported by direct binding of CpG ODNs to commercially available human hsp90. Additionally, immunohistochemistry studies showed redistribution of hsp90 upon CpG ODN uptake. Thus, we propose that hsp90 can act as a ligand transfer molecule and/or play a central role in the signaling cascade induced by CpG DNA. Received 18 December 2002; accepted 6 January 2002 RID="*" ID="*"Corresponding author. B. Agerberth and G. H. Gudmundsson contributed equally to this work.     

T-cell-mediated enhancement of host-versus-graft reactivity in mice fed a diet enriched in vitamin A acetate

Retinol (vitamin A) and some of its derivatives have an important role in: (1) regulating growth, proliferation and differentiation of various tissues and (2) maintaining reproduction and visual function in man and higher animals. Vitamin A and retinoids are also known as potent immunoregulatory and antineoplastic agents. Their ability to increase reactivity to histoincompatible tissues is well documented but the mechanism of this action is unclear. Here we report that mice fed on an otherwise conventional diet supplemented with vitamin A acetate (VAA) respond to 10(5) semiallogeneic cells (a suboptimal dose) in a host-versus-graft (HvG) reaction, whereas mice on a conventional diet do not. It is possible to transfer this enhanced immune reactivity by injecting lymphoid cells from VAA-fed animals into those syngeneic mice maintained on the conventional diet. Using a positive selection technique, we demonstrate that the phenotype of the cell probably responsible for this phenomenon is Lyt 1+ 2-.