Interactions between flagellar and type III secretion proteins in <Emphasis Type="Italic">Chlamydia pneumoniae</Emphasis>

Background  

Flagellar secretion systems are utilized by a wide variety of bacteria to construct the flagellum, a conserved apparatus that allows for migration towards non-hostile, nutrient rich environments. Chlamydia pneumoniae is an obligate, intracellular pathogen whose genome contains at least three orthologs of flagellar proteins, namely FliI, FlhA and FliF, but the role of these proteins remains unknown.     

Immune response differences between two inbred chicken lines identical at the major histocompatibility complex

We compared two of the East Lansing Regional Poultry Research Laboratory inbred chicken lines for immune responses to four antigens injected in Freund's complete adjuvant, and to the chemical oxazolone as a contact sensitizer. Line EL6 chickens gave higher delayed hypersensitivity responses than did EL7 birds to BSA, dodecanoic acid-conjugated BSA, and ferritin, as well as to oxazolone. Line EL6 gave the higher primary antibody responses to the first three of these antigens, but EL7 gave the higher responses to the hapten DNP. Since these lines are identical for theB major histocompatibility complex by serological and functional tests, these results imply the existence of differences in levels of immune responsiveness which are apparently non-MHC-associated.     

H-NMR of G-U-C and G-U-C-C in D2O: assignment of nonexchangeable protons and analysis of solution conformation

The ribonucleotide oligomers G-U-C and G-U-C-C have been synthesized enzymatically. These oligomers are cognates of the m⁷G⁴⁶-U⁴⁷-C⁴⁸-m⁵C⁴⁹ sequence found in the variable loop of t-RNA^phe. The ¹H-NMR chemical shifts of the base and ribose Hl; protons as well as the couplings. J_1'–2' of the ribose protons have been examined as a function of temperature. Assignments for these resonances have been completed, and used in the analysis of solution conformation for these oligomers. The results are consistent with the basic features of the A-RNA structure and suggest the absence of alternative ordered solution structures.     

Antithrombotic potential of dihomo-gamma-linolenic acid in man.

The effects of orally ingested dihomo-gamma-linolenic acid (DHLA), the natural biosynthetic precursor of prostaglandin E1 (PGE1), were assessed in human volunteers. Single doses of DHLA (0.1--2g) increased the proportion of DHLA relative to arachidonic acid in plasma and platelets and also increased the ex-vivo capacity of platelets to produce PGE1 and PGE2. More pronounced effects were observed during sustained treatment (five days to four weeks) when DHLA also accumulated in red cell membranes. These biochemical changes were accompanied by potentially antithrombotic changes in haemostatic function. The most common effect, which was consistently detected after 0.1-g single doses of DHLA or its methyl ester, was a decrease in plasma heparin-neutralising activity. Inhibition of platelet aggregation induced by adenosine diphosphate was also detected, though this was generally less pronounced. Sustained treatment in one subject also produced definite inhibition of ristocetin-induced platelet aggregation. There was only one possible adverse effect--a transient cough in a subject with a history of asthma. DHLA therefore seems to have considerable potential as an agent for preventing and treating human thromboembolic disease.