Improved storage mitigates vulnerability to food-supply shocks in smallholder agriculture during the COVID-19 pandemic.

Millions of smallholder farmers in low-income countries are highly vulnerable to food-supply shocks, and reducing this vulnerability remains challenging in view of climatic changes. Restrictions to limit the spread of the COVID-19 pandemic produced a severe supply-side shock in rural areas of Sub-Saharan Africa, including through frictions in agricultural markets. We use a large-scale field experiment to examine the effects of improved on-farm storage on household food security during COVID-19 restrictions. Based on text message survey data we find that the prevalence of food insecurity increased in control group households during COVID-19 restrictions (coinciding with the agricultural lean season). In treatment households, equipped with an improved on-farm storage technology and training in its use, food insecurity was lower during COVID-19 restrictions. This underscores the benefits of improved on-farm storage for mitigating vulnerability to food-supply shocks. These insights are relevant for the larger, long-term question of climate change adaptation, and also regarding trade-offs between public health protection and food security.

Guinea pig lung tryptase. Localisation to mast cells and characterisation of the partially purified enzyme.

Tryptase (EC 3.4.21.59), the major secretory product of human mast cells, has become widely used as a biochemical marker for mast cells and mast cell activation, and is attracting attention as a mediator of allergic disease. However, there is little information available on the properties, or even the presence, of this protease in commonly used species of laboratory animals. We, here, report the demonstration and characterisation of this enzyme in the guinea pig lung. Tryptic activity resistant to alpha 1-proteinase inhibitor and soybean trypsin inhibitor was detected in sections of guinea pig lung tissue with the histochemical substrate Z-Gly-Pro-Arg-MNA. It was localised to mast cells and appeared to be present in all mast cells staining with Alcian Blue. A tryptic protease was purified 2400-fold from whole lung tissue by high salt extraction, cetylpyridinium chloride precipitation, heparin agarose chromatography, and gel filtration. This enzyme was found to be multimeric with a subunit of 38 kDa and a native molecular mass of 860 +/- 100 kDa. Inhibitor studies identified it as a serine protease. Like human tryptase, it was inhibited by leupeptin, benzamidine, and APC 366 (N-(1-hydroxy-2- naphthoyl)-L-arginyl(-L-prolinamide hydrochloride), but not by alpha 1-proteinase inhibitor, soybean trypsin inhibitor, or antithrombin III. Its response to changes in pH and ionic strength was similar to that of human tryptase. Differences between the guinea pig and human enzymes were seen in activity toward a panel fo 10 tryptic p_nitroanilide peptide substrates. Kinetic constants were determined for two of these: with L-Pyr-Pro-Arg-pNA the guinea pig tryptase had a similar Km but a 5-fold lower kcat than human tryptase, and with L-Pyr-Gly-Arg-pNA the guinea pig enzyme had a 10-fold lower Km and a 30% greater kcat than human counterpart. Heparin stabilised guinea pig tryptase, but did not alter its kinetic parameters as it did with human tryptase, decreasing the Km towards both substrates. The presence of a protease with similarities to human tryptase in the mast cells of guinea pigs suggests that this species may be an appropriate model to investigate the actions to tryptase in vivo, provided cognizance is taken of the differences that do exist.

Evaluation of the RapID ANA II and API ZYM systems for identification of Actinomyces species from clinical specimens.

Classification and identification of fermentative actinomycetes are labor-intensive and problematic. In this study, we evaluated the applicability and reliability of the RapID ANA II system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) and the discriminatory value of the API ZYM system (Societes Analytab Products Inc., La Balme Les Grottes, France) in the identification of Actinomyces-like bacteria by using conventional methods as a reference. Eighty-five strains, including 71 isolates from mixed anaerobic infections and 14 reference strains, were tested. The RapID ANA II system correctly identified all Actinomyces odontolyticus strains and 65% of Actinomyces israelii strains. All Arcanobacterium haemolyticum strains were misidentified as Actinomyces pyogenes. The most common isolates in the study were Actinomyces meyeri-like organisms, 84% of which, however, were aerotolerant. The identification of these aerotolerant strains thus remains unresolved and warrants further studies. New characteristics and changes to the conventional API ZYM enzyme profiles are suggested. The API ZYM enzyme profiles of A. odontolyticus and A. israelii were very similar, the only discriminating enzyme being alpha-fucosidase. In differentiation between A. pyogenes and Arcanobacterium haemolyticum, the production of beta-glucuronidase by the former and the production of acid phosphatase by the latter are suggested as new helpful characteristics for use in clinical laboratories. In summary, the RapID ANA II and API ZYM systems can be used as rapid preliminary methods in the identification of Actinomyces species but accurate identification requires supplementary conventional tests and gas-liquid chromatography.

Listeria monocytogenes septicemia associated with consumption of salted mushrooms.

Listeria monocytogenes septicemia in an 80-year-old man is described. On the day before clinical symptoms appeared the patient had eaten homemade salted mushrooms, rufous milkcap (Lactarius rufus Fr.). L. monocytogenes serotype 4b was isolated in blood cultures. The mushrooms which had been stored in cold for 5 months before consumption contained the same listeria serotype at a level of 10(6) CFU/g. Salt content (NaCl) of the mushrooms was 7.5%. Fever and diarrhea disappeared with penicillin therapy and the patient was discharged after 4 weeks in the hospital.