Based on our results, we cannot deny the possibility of HPV16 involvement in the carcinogenesis of the esophagus.

Aluminum toxicity limits plant growth in acid soils. Because of Many of these studies were conducted with solution their advanced state of weathering, acid soils of the tropics also tend culture rather than with soil to circumvent the problem to be deficient in nutrients. A realistic assessment of plant adaptation to these soils would therefore require Al-toxic conditions under which that several soil properties change simultaneously when growth is simultaneously limited by nutrient deficiency. We developed soil acidity is modified. Initially, solutions contained and tested a nutrient solution for this purpose. We analyzed soil nutrient levels far in excess of those required for maxisolutions of two Oxisols from the Colombian savannas. Nutrient conmum plant growth rates (see critiques by Blamey et al. centrations were extremely low (ionic strength Ͻ1.7 mM). Nitrifica-[1991] and Edmeades et al. [1995]). In such solutions, tion during incubation of soil samples acidified soil solutions, resulting Al toxicity is alleviated as a result of physicochemical in a release of cations from the exchange phase, an increase in the interactions between Al and other ions, including the activity of Al 3؉ , and a decrease in that of H 2 PO Ϫ 4. Predicted ion formation of nontoxic complexes with OH Ϫ , SO 2Ϫ 4 , and activities were taken as guidelines for designing a nutrient solution silicate ions; precipitation of Al as hydroxide or phosthat simulates these soil solutions. Growth of well-adapted signalgrass phate; and high ionic strength per se (Blamey et al., (Brachiaria decumbens cv. Basilisk) and less-adapted ruzigrass (Brachiaria ruziziensis cv. Common) in this solution mirrored the 1983; Blamey et al., 1991; Wheeler and Edmeades, 1995; interspecific difference in forage yield that had previously been ob-Kinraide, 1997; Ma et al., 1997). In addition, high conserved in a field close to where one of the soils originated. This centrations of divalent and, to a lesser extent, monovasuggests that the designed solution may be a realistic approximation lent cations can ameliorate Al toxicity, presumably beto chemical soil properties that limit forage productivity. The different cause they reduce cell-surface negativity (Kinraide and growth response of the two grasses was apparently due to increased

A B S T R A C TBackgroundDetection and characterization of viral RNA pathogens from fieldwork are challenging due to the instability of the RNA molecule. FTA cards® have proved useful for sample storage and latter identification of pathogens with importance for agricultural, animal and human health: however, for optimal handling, processing, and biosafety measures are not well-established.ObjectiveThis systematic review aims to summarize the reported effectiveness of FTA cards® for storage and transport of viral RNA, as well as the conditions for their handling and use in downstream processes. Finally, the biosafety measures required to protect researchers and clinical lab workers are considered.MethodsWe performed a systematic review following the PRISMA statement. We searched MEDLINE (PubMed), Scopus and Web of Science using the keywords "FTA cards" AND "RNA". Articles were screened by title and abstract, and after examination of inclusion and exclusion criteria, relevant information was extracted. The quality of the studies was assessed, and the evidence was qualitatively summarized.ResultsA total of 175 records were retrieved, and 11 additional documents were found by checking references of the eligible articles. A total of 47 articles were included. Samples from animals accounted for 38.3% of the publications, which identified viruses that cause disease in poultry, wild birds, suids, or bovids. Three different methods for RNA extraction were reported. Other factors that vary across reports include the size of RNA amplicon, storage temperature, and duration of storage. Only fourteen articles tested the inactivation of the virus on the FTA card®, and in one case, the virus remained infective.ConclusionFTA cards® could be a suitable option for RNA virus storage and transport for fieldwork in areas where proper conditions for RNA preservation are difficult to achieve. Three different protocols have been used for RNA detection from this matrix. Biospecimens in the form of dried blood spots should be considered potentially infectious unless specifically treated to inactivate viral pathogens. technology consists of filter paper impregnated with a patented chemical mixture that contains chemical denaturants and a free radical scavenger. The chemical mixture lyses cells and organelles, prevents overgrowth of bacteria, and denatures proteins. The DNA is captured in the matrix and remains tightly bound while proteins and inhibitors are washed. This keeps DNA stable during long-term storage at room temperature (GE Healthcare, 2019).

The major surface protein MSP‐1 of Plasmodium falciparum blood‐stage malaria parasites contains notably conserved sequence blocks with unknown function. The recombinant protein 190L, which represents such a block, exhibits a high affinity for red blood cell membranes. We demonstrate that both 190L and native MSP‐1 protein bind to the inner red blood cell membrane skeleton protein spectrin. By using overlapping peptides covering the 190L molecule, we show that the spectrin contact site of 190L is included in a linear sequence of 30 amino acid residues. Association of 190L with naturally occurring spectrin deficient red blood cells is drastically reduced. In the same cells parasite invasion is normal, but the intracellular parasite development arrests late in the trophozoite stage. A similar situation arises when synthetic peptides covering the spectrin recognition sequence of 190L are added to P.falciparum cultures. These data and the cellular localization of MSP‐1 suggest the possibility that MSP‐1 associates with spectrin under natural conditions.

No abstract