Contents of Volume 53

Plant Molecular Biology -     

Complete Genome Sequence of Hepatitis E Virus from Rabbits in the United States

Hepatitis E virus (HEV) is a single-strand positive-sense RNA virus in the family Hepeviridae. The disease caused by HEV, hepatitis E, is an important public health problem in developing countries of Asia and Africa and is also endemic in many industrialized countries, including the United States. HEV has been identified from several other animal species in addition to humans, including the pig, chicken, mongoose, deer, rabbit, ferret, bat, and fish. Here we report the complete genome sequence of the first strain of HEV from rabbits in the United States. Sequence and phylogenetic analyses revealed that the U.S. rabbit HEV is a distant member of the zoonotic genotype 3 HEV, thus raising a concern for potential zoonotic human infection. A unique 90-nucleotide insertion within the X domain of the ORF1 was identified in the rabbit HEV, and this insertion may play a role in the species tropism of HEV.     

Soil Properties,Nutrient Dynamics,and Soil Enzyme Activities Associated with Garlic Stalk Decomposition under Various Conditions

The garlic stalk is a byproduct of garlic production and normally abandoned or burned, both of which cause environmental pollution. It is therefore appropriate to determine the conditions of efficient decomposition, and equally appropriate to determine the impact of this decomposition on soil properties. In this study, the soil properties, enzyme activities and nutrient dynamics associated with the decomposition of garlic stalk at different temperatures, concentrations and durations were investigated. Stalk decomposition significantly increased the values of soil pH and electrical conductivity. In addition, total nitrogen and organic carbon concentration were significantly increased by decomposing stalks at 40°C, with a 5∶100 ratio and for 10 or 60 days. The highest activities of sucrase, urease and alkaline phosphatase in soil were detected when stalk decomposition was performed at the lowest temperature (10°C), highest concentration (5∶100), and shortest duration (10 or 20 days). The evidence presented here suggests that garlic stalk decomposition improves the quality of soil by altering the value of soil pH and electrical conductivity and by changing nutrient dynamics and soil enzyme activity, compared to the soil decomposition without garlic stalks.     

Nutrition and muscle potassium: differential effect in rat slow and fast muscles

The effects of malnutrition on intracellular K+ activity, (alpha K)i, and membrane potential, Em, were measured by means of double-barrelled K+-selective microlectrodes in the soleus and gastrocnemius muscles of the rat. (alpha K)i and Em were measured in vivo in normal anaesthetized animals and in rats subjected to one of two diet restrictions: a 2-day fast or a long-term hypocaloric diet. In the soleus muscle, (alpha K)i fell by similar amounts in both 2-day fasted and long-term hypocalorically fed rats, while Em depolarized significantly only in hypocalorically fed rats. In the gastrocnemius muscle, neither the 2-day fast nor the hypocaloric diet affected (alpha K)i or Em. It is suggested that the selective loss of K+ from the soleus muscle may be related to its activity pattern.     

Forskolin stimulation of pepsinogen secretion from frog esophageal mucosa is partly mediated by intrinsic cholinergic neurons

Forskolin was found to stimulate pepsinogen secretion from frog esophageal mucosa. The stimulation was dose-dependent and was accompanied with a great increase in tissue cAMP content. The response to forskolin mimicked the action of bethanechol and was not additive with bethanechol. The stimulatory effect of forskolin was inhibited by 50% in the presence of either atropine or tetrodotoxin. On the other hand, incubation in a calcium-free medium not only reduced the response to forskolin by 45% but also eliminated the influence of atropine and tetrodotoxin. These results indicate that forskolin may stimulate pepsinogen secretion from the frog esophageal mucosa via activating adenylate cyclase, and part of its effect may arise from eliciting acetylcholine release from the intrinsic neurons.     

Incidence of three cross-reactive idiotypes on human rheumatoid factor paraproteins

The basis for rheumatoid factor (RF) production in autoimmune or lymphoproliferative diseases cannot be understood without defining the molecular factors that dictate RF structure and specificity. Recently three different mAb (6B6.6, 17.109, and G6) have been developed that define cross-reactive idiotypes (CRI) on intact L or H chains of human monoclonal RF cryoglobulins. However, the true incidence of these CRI among RF and their relationship to each other have not been delineated. In the present experiments, a panel of 163 randomly selected IgM paraproteins was evaluated for the expression of the two kappa L chain CRI, 6B6.6 and 17.109, and the H chain CRI, G6. Among the paraproteins with kappa L chains, 14% expressed the 17.109 CRI, and 9% expressed the 6B6.6 CRI. Both ELISA and Western immunoblotting experiments showed that the two L chain CRI were mutually exclusive. Anti-IgG activity was documented in 22 of the IgM-kappa paraproteins, among which mAb 6B6.6 reacted with 7 (32%) and mAb 17.109 with 6 (27%). Both CRI were expressed exclusively by L chains within the kappaIII variable gene subgroup. Although 17.109 CRI+ paraproteins had kappaIIIb L chains, none of the 6B6.6 CRI+ paraproteins possessed L chains with this kappa sub-subgroup specific Ag. The G6 CRI was found predominantly among RF paraproteins and was frequently yet not exclusively associated with the 17.109 CRI+ L chains. Additional experiments were performed on a panel of normal adult human sera and documented the presence of 6B6.6 and 17.109 CRI on a small percentage (0.1 to 2.0%) of IgM from most individuals. These data indicate that 1) the mAb 6B6.6 and 17.109 identify two major and distinct CRI among IgM-RF paraproteins, 2) both CRI are associated exclusively with kappaIII L chains, 3) kappaIIIb and kappaIII non-b L chains are equally prevalent among IgM-RF, 4) the G6 H chain CRI is frequently associated with 17.109 CRI+ L chains, but not with 6B6.6 CRI+ L chains, and 5) although the ability to make 6B6.6 and 17.109 CRI+ kappa L chains is common in humans, these CRI are present in low concentrations in normal IgM.