Is the flavin-deficient red blood cell common in Maremma, Italy, an important defense against malaria in this area?

There is a high prevalence of a familial flavin-deficient red blood cell in Ferrara province in the Po delta in northern Italy, believed to have been selected for by malaria which was endemic from the 12th century. In the present study, activities of FAD-dependent red-cell glutathione reductase (EGR) in the Grosseto area of Maremma on the west coast of Italy where malaria was endemic from 300 B.C. are compared both with activities in the Ferrara area and with activities where there was no history of endemic malaria--in the Florence area and in London in people of Anglo-Saxon origin. EGR activities were similar in Grosseto and Ferrara and were significantly lower than in Florence and London. As previously found in Ferrara, low EGR activity in Grosseto was shown to be unrelated to low dietary riboflavin intake. These findings in Grosseto, suggesting selection by malaria, are particularly interesting because, unlike the situation in Ferrara and most other malarial areas, the prevalence of thalassemia and glucose-6-phosphate dehydrogenase deficiency is very low, and they do not appear to have been selected for in Maremma. It is possible that a flavin-deficient red cell, known to inhibit growth of the malaria parasite, was an important protecting factor in the population of this area over the centuries.     

The functioning of ectomycorrhizal fungi in the field: linkages in space and time

Individual trees, either of the same or different species, can be linked spatially and temporally by the hyphae of ectomycorrhizal (ECM) fungi that allow carbon and nutrients to pass among them and promote forest establishment following disturbance. Spatial and temporal linkages between plants influence the function of ECM fungi in the field. Studies indicate that ECM linkages can reduce plant competition for resources, promote forest recovery, and influence the pattern of plant succession. The degree of influence depends on many factors, including the composition and arrangement of the vegetative community and soil and climatic conditions. Management practices that create intense disturbance and loss of organic matter or promote the introduction of non-ectomycorrhizal host species can decrease the ability of plants to form linkages with ECM fungi. Management practices that retain living trees and shrubs and input of organic matter provide the energy source and substrate necessary for ECM linkages. More research is needed to determine the degree to which ECM fungal linkages occur in the field and their role in ecosystem function and long-term health.     

Bioluminescent Salmonella typhimurium provides a rapid assay for measuring the efficacy of freeze-drying suspension media

A strain of Salmonella typhimurium , transformed to a bioluminescent phenotype, was used to compare three freeze-drying suspension media: inositol serum broth with and without added gelatin and sterile skimmed milk. Recovery and growth studies performed by measuring changes in bioluminescence demonstrated that of the three media tested, the routinely used inositol serum broth was the most effective freeze-drying suspension medium.     

Differential recovery of polymorphonuclear neutrophils,B and T cell subpopulations in the thymus,bone marrow,spleen and blood of mice following split-dose polychemotherapy

In these studies, we examined the effect of a maximum-tolerated, split-dose chemotherapy protocol of cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea carmustine on neutrophil and lymphocyte subpopulations in the peripheral blood (PBL), thymus, bone marrow and spleen. It was found that this protocol of polychemotherapy, modeled after the induction protocol used with autologous bone marrow transplantation for breast cancer, suppressed both B and T cell populations and T cell function at times when the absolute neutrophil count had returned to normal or supernormal numbers. In the peripheral blood, 7 days following initiation of chemotherapy, there was a twofold increase in the percentage of granulocytes as compared to the level in control animals on the basis of a differential count. The polymorphonuclear neutrophil (PMN) frequency in the bone marrow was increased on day 14 and statistically identical to that in control mice on all other days analyzed. In contrast to the bone marrow cells and PBL on day 7, the frequency of PMN in the spleen and thymus was depressed. B cells (B220+) were depressed in the PBL, spleen and bone marrow and took 18–32 days to return to their normal frequency, while the frequency of B cells in the thymus was increased owing to a loss of immature T cells. The percentage of CD3+ cells in the thymus, spleen and bone marrow was significantly increased and required 10–18 days to return to normal levels, while the absolute number of CD3+ cells in the blood varied around the normal value. The ratio of CD4+ to CD8+ cells in all the organs studied varied only slightly owing to a similar reconstitution of CD4+ and CD8+ cells. In contrast to the phenotypic recovery of the CD3+, CD4+ and CD8+ cells, the ability of the splenic lymphocytes to respond to concanavalin-A was depressed and remained depressed, despite the phenotypic reconstitution of the T cell subsets, on the basis of both percentage and absolute cell number. These results show a selective T and B cell depression following multi-drug, split-dose chemotherapy in tissue and blood leukocyte populations and a chronic depression in T cell function.     

Monocarbonyl Analogs of Curcumin with Potential to Treat Colorectal Cancer

Curcumin has a plethora of biological properties, making this compound potentially effective in the treatment of several diseases, including cancer. However, curcumin clinical use is compromised by its poor pharmacokinetics, being crucial to find novel analogs with better pharmacokinetic and pharmacological properties. Here, we aimed to evaluate the stability, bioavailability and pharmacokinetic profiles of monocarbonyl analogs of curcumin. A small library of monocarbonyl analogs of curcumin 1a–q was synthesized. Lipophilicity and stability in physiological conditions were both assessed by HPLC-UV, while two different methods assessed the electrophilic character of each compound monitored by NMR and by UV-spectroscopy. The potential therapeutic effect of the analogs 1a–q was evaluated in human colon carcinoma cells and toxicity in immortalized hepatocytes. Our results showed that the curcumin analog 1e is a promising agent against colorectal cancer, with improved stability and efficacy/safety profile.     

Genotype and phenotype associations with drought tolerance in barley tested in North Africa

A review is presented of genetic strategies deployed in a 3-yr project on drought tolerance in barley. Data were collected on genetic, physiological and agronomic traits in non-irrigated and irrigated field trials in Egypt, Morocco and Tunisia. A wide range of barley germplasm (developed from African and European cultivars, adapted landraces and wild barleys) was tested, and positive traits were found in each gene pool. The contrasting environments of the three North African countries had major effects on plant/genotype performance. Genetic effects were also detected, as were genotype × environment interactions. A range of strategies were deployed to investigate the physiology and genetics of quantitative traits associated with field performance. Quantitative trait locus (QTL) analysis was performed using backcross lines, recombinant inbred lines and doubled haploid mapping populations. A detailed genetic map was generated in the Tadmor × (ER/Apm) recombinant inbred lines, an important mapping population specifically developed by ICARDA (Centre for Agricultural Research in Dry Areas) and CIMMYT (International Maize and Wheat Improvement Center) to study drought. Quantitative trait loci (QTLs) for grain yield and other important morphological and physiological traits were also identified in a population of doubled haploids derived from F2BCj plants from a cross between a cultivar and a wild barley accession. Significantly, the wild parental line was found to contribute a number of positive alleles for yield. Effects of major developmental genes could explain many of the responses observed. QTLs were found to cluster around major genes controlling flowering time (sghI), plant stature (sdwI and arie.GP) and ear type (vrsl), and it is highly likely that the associations represent pleiotropic effects. Some QTLs were associated with candidate genes such as dehydrins and rubisco activase. One of the most significant results was the identification and generation of material that out performed the best local standards in the three participating North African countries; the selected lines have now entered local breeding programmes. The strategies adopted provided information on physiological traits, genotypes and genetic markers that could be used for marker-assisted selection. Target QTLs and their associated genetic markers may be deployed in marker assisted selection programmes to match crop phenology to the field environment.     

The hmu locus of Yersinia pestis is essential for utilization of free haemin and haem-protein complexes as iron sources

Yersinia pestis strains utilize haem and several haem-protein complexes as sole sources of iron. In this study, the haemin uptake locus (hmu) of Y. pestis KIM6+ was selected from a genomic library by trans-duction into an Escherichia coli siderophore synthesis (entC) mutant. Recombinant plasmids containing a common 16 kb BamHI insert were isolated that allowed E. coli entC to use haemin as an iron source. An 8.6 kb region of this insert was found to be essential for haemin utilization and encoded at least five proteins with molecular masses of 79/77, 44, 37, 35, and 30/27.5 kDa. A 10.9 kb Clal fragment containing the hmu locus showed varying degrees of homology to genomic DNA from Yersinia pseudotuberculosis, Yersinia enter-ocolitica, and other genera of Enterobacteriaceae. An E. coli hemA aroB strain harbouring cloned hmu genes used haemin as both an iron and porphyrin source but only on iron-poor medium, suggesting that haemin uptake is tightly iron regulated. Additionally, haemoglobin and myoglobin were used as iron sources by an E. coli entC (pHMU2.2) strain. Deletion of the hmu locus from Y. pestis KIM6+ chromosome generated a mutant that grew poorly on iron-depleted medium containing free haemin as well as mammalian haem-protein complexes including haemoglobin, haemoglobin-haptoglobin, myoglobin, haem-haemopexin, and haem-albumin unless it was complemented with cloned hmu genes.