Human respiratory tract secretions: Mucous glycoproteins of nonpurulent tracheobronchial secretions,and sputum of patients with bronchitis and cystic fibrosis

Mucous glycoproteins were isolated by agarose gel filtration from nonpurulent tracheobronchial secretions and purulent sputum which had been reduced, carboxymethylated and, in the case of purulent secretions, treated with deoxyribonuclease. The solubilized and purified glycoproteins were fractionated on diethylaminoethyl cellulose into two major (I, II) and two minor (Ia, III) blood group active components. Components I and II had similar carbohydrate and amino acid compositions which were typical for human blood group substances. These two components did differ in several respects. Component I contained 1.4–2.6% sulfate and did not inhibit influenza virus hemagglutination while component II contained 7.1–7.8% sulfate and was a potent inhibitor of virus hemagglutination. Component II also migrated more rapidly on sodium dodecyl sulfate-3.3% acrylamide gel electrophoresis. Components I and II in purulent secretions displayed only minor compositional differences from their counterparts in nonpurulent secretions. Component II was more abundant in two sputum samples from subjects with cystic fibrosis than in purulent bronchitic secretions or in nonpurulent secretions.     

Outside-host phage therapy as a biological control against environmental infectious diseases

Background

Environmentally growing pathogens present an increasing threat for human health, wildlife and food production. Treating the hosts with antibiotics or parasitic bacteriophages fail to eliminate diseases that grow also in the outside-host environment. However, bacteriophages could be utilized to suppress the pathogen population sizes in the outside-host environment in order to prevent disease outbreaks. Here, we introduce a novel epidemiological model to assess how the phage infections of the bacterial pathogens affect epidemiological dynamics of the environmentally growing pathogens. We assess whether the phage therapy in the outside-host environment could be utilized as a biological control method against these diseases. We also consider how phage-resistant competitors affect the outcome, a common problem in phage therapy. The models give predictions for the scenarios where the outside-host phage therapy will work and where it will fail to control the disease. Parameterization of the model is based on the fish columnaris disease that causes significant economic losses to aquaculture worldwide. However, the model is also suitable for other environmentally growing bacterial diseases.

Results

Transmission rates of the phage determine the success of infectious disease control, with high-transmission phage enabling the recovery of the host population that would in the absence of the phage go asymptotically extinct due to the disease. In the presence of outside-host bacterial competition between the pathogen and phage-resistant strain, the trade-off between the pathogen infectivity and the phage resistance determines phage therapy outcome from stable coexistence to local host extinction.

Conclusions

We propose that the success of phage therapy strongly depends on the underlying biology, such as the strength of trade-off between the pathogen infectivity and the phage-resistance, as well as on the rate that the phages infect the bacteria. Our results indicate that phage therapy can fail if there are phage-resistant bacteria and the trade-off between pathogen infectivity and phage resistance does not completely inhibit the pathogen infectivity. Also, the rate that the phages infect the bacteria should be sufficiently high for phage-therapy to succeed.

     

The newly synthesized plant growth regulator <Emphasis Type="Italic">S</Emphasis>-methylmethionine salicylate may provide protection against high salinity in wheat

High salinity is one of the major environmental factors limiting the productivity of crop species worldwide. Improving the stress tolerance of cultivated plants and thus increasing crop yields in an environmentally friendly way is a crucial task in agriculture. In the present work the ability of a new derivative, S-methylmethionine-salicylate (MMS), to improve the salt tolerance of wheat plants was tested parallel with its related compounds salicylic acid and S-methylmethionine. The results show that while these compounds are harmful at relatively high concentration (0.5 mM), they may provide protection against high salinity at lower (0.1 mM) concentration. This was confirmed by gas exchange, chlorophyll content and chlorophyll-a fluorescence induction measurements. While osmotic adjustment probably plays a critical role in the improved salt tolerance, neither Na or K transport from the roots to the shoots nor proline synthesis are the main factors in the tolerance induced by the compounds tested. MMS, S-methylmethionine and Na-salicylate had different effects on flavonol biosynthesis. It was also shown that salt treatment had a substantial influence on the SA metabolism in wheat roots and leaves. Present results suggest that the investigated compounds can be used to improve salt tolerance in plants.     

MICROTUBULE PROTEIN DURING CILIOGENESIS IN THE MOUSE OVIDUCT

A colchicine-binding assay and quantitative sodium dodecyl sulfate gel electrophoresis have been used to determine the changes which occur in microtubule protein (tubulin) concentrations in the particulate and soluble fractions of mouse oviduct homogenates during that period of development when centriole formation and cilium formation are at a maximum. When mouse oviducts, at various ages after birth, are homogenized in Tris-sucrose buffer, tubulin concentration is partitioned between the soluble (70%) and particulate (30%) fractions. During the period of most active organelle formation (3–12 days), there is a marked increase in colchicine-binding specific activity, in both the soluble and particulate fractions. Microtubule protein concentration increases from 16 to 24% in the soluble fraction, declining to 14% in the adult. In the particulate fractions, microtubule protein concentration increases from 16 to 27%, leveling off at 16% in the adult. We have concluded from these observations and from electron microscopy that colchicine-binding activity in the particulate fractions is related to the presence of centriole precursors in the pellets of homogenized oviducts from newborn mice. These data further suggest that centriole precursor structures are conveniently packaged aggregates of microtubule protein actively synthesized between 3 and 5 days, and maintained at a maximum during the most active period of organelle assembly.     

Isolation of dsRNA-associated VLPs from the strain Cryptococcus hungaricus CBS 6569

Double-stranded RNAs (dsRNAs) with molecular masses 1.7 and 5.0 kbp, respectively, were isolated from the strain Cryptococcus hungaricus CBS 6569. The dsRNAs were copurified with eicosahedric virus-like particles, 29 nm in diameter. This strain produced a protease-sensitive `toxin' which inhibited the growth of strain C. hungaricus CBS 4214. The toxin had maximum activity at pH 3.7. The highest toxin amount was attained after a culture period of four days.     

Influence of a low-carbohydrate diet on thermoregulatory responses to prolonged exercise in men

Tympanic temperature (T_ty), mean skin temperature (T_sk) and dynamics of sweating were measured in male subjects, performing prolonged, bicycle-exercise. The exercise was performed under thermoneutral environment after the normal-mixed (C) and low-carbohydrate (LCHO) diet. No difference in changes of T_ty was observed after the C and LCHO diets. Sweating was triggered much faster after the LCHO diet. The delay in onset and inertia time of sweating was shorter after the LCHO diet. It is concluded that LCHO diet affects the thermoregulatory responses to exercise by acceleration of sweating, without noticeable differences in body temperature.