In the course of an analysis of the functions and assembly of the cell wall of Candida albicans, we have cloned and characterized a gene, which we designated CSP37 (cell surface protein), encoding a 37-kDa polypeptide which is a membrane-associated protein. Candida albicans is an imperfect fungus capable of causing life-threatening infections in immunocompromised patients as well as a variety of mucosal infections in generally healthy individuals (50). Due to its importance as a human pathogen and the limited number of safe drugs to control deep-rooted infections, many laboratories have undertaken cellular, molecular, and genetic studies to understand the mechanisms governing C. albicans biology. However, the diploid nature of this fungus and the failure to identify a sexual cycle have hampered many classical genetic approaches (59).A number of factors are thought to contribute to the virulence of C. albicans, but their relative importance during pathogenesis remains unclear (14). Potential virulence determinants include the ability to switch from a yeast to a mycelial form (31,62) and also between different colonial morphologies (64), the production of extracellular hydrolytic enzymes (28, 36), synthesis of receptor-ligand molecules required for recognition, and adhesion to the host tissues (7, 8), etc. Since the cell wall is involved in these processes, some groups have attempted to elucidate the mechanism of synthesis of its different constituents, their assembly, and the modifications that occur during the morphological transition. Thus, a number of cell surface antigens have been reported to be preferentially expressed in hyphal or blastoconidial cell morphologies (10,52,66,67), and several genes related to cell wall architecture (assembly and functions) have been cloned. These genes have been identified by various methods, including differential hybridization screening (27), complementation in Saccharomyces cerevisiae (3), cross-hybridization with genes cloned from other organisms (heterologous genes) (20, 65), hybridization with sequence-specific oligonucleotides (9), and PCR amplification (11,12). We have used another approach to clone morphologyspecific C. albicans genes related to the cell wall. We have isolated cDNA clones by screening with polyclonal antibodies raised against isolated cell walls of blastoconidia and mycelial cells (17,61).In this paper, a cDNA clone that reacted with polyclonal antibodies specific for mycelial cell walls was studied. It encodes a novel protein with no significant homology to known sequences and absent from the S. cerevisiae genome. ⌬csp37 null mutants were constructed and subsequently phenotypic analysis and virulence testing were conducted. Location of the protein codified and potential functions are discussed. MATERIALS AND METHODSMicroorganisms and growth conditions. The C. albicans strains used in this study are listed in Table 1. Cells were routinely grown in YPD (2% glucose, 1% yeast extract, 2% Bacto Peptone [Difco, Detroit, Mich.]) with shaking at the selecte...

We conclude that PCR is a useful tool for the early detection of parasite susceptibility to benznidazole and for the post-treatment parasitological follow-up of patients with chronic Chagas' disease.

Background Infection by the SARS-Cov-2 virus produces in humans a disease of highly variable and unpredictable severity. The presence of frequent genetic single nucleotide polymorphisms (SNPs) in the population might lead to a greater susceptibility to infection or an exaggerated inflammatory response. SARS-CoV-2 requires the presence of the ACE2 protein to enter in the cell and ACE2 is a regulator of the renin-angiotensin system. Accordingly, we studied the associations between 8 SNPs from AGTR1, ACE2 and ACE genes and the severity of the disease produced by the SARS-Cov-2 virus. Methods 318 (aged 59.6±17.3 years, males 62.6%) COVID-19 patients were grouped based on the severity of symptoms: Outpatients (n = 104, 32.7%), hospitalized on the wards (n = 73, 23.0%), Intensive Care Unit (ICU) (n = 84, 26.4%) and deceased (n = 57, 17.9%). Comorbidity data (diabetes, hypertension, obesity, lung disease and cancer) were collected for adjustment. Genotype distribution of 8 selected SNPs among the severity groups was analyzed. Results Four SNPs in ACE2 were associated with the severity of disease. While rs2074192 andrs1978124showed a protector effectassuming an overdominant model of inheritance (G/A vs. GG-AA, OR = 0.32, 95%CI = 0.12–0.82; p = 0.016 and A/G vs. AA-GG, OR = 0.37, 95%CI: 0.14–0.96; p = 0.038, respectively); the SNPs rs2106809 and rs2285666were associated with an increased risk of being hospitalized and a severity course of the disease with recessive models of inheritance (C/C vs. T/C-T/T, OR = 11.41, 95% CI: 1.12–115.91; p = 0.012) and (A/A vs. GG-G/A, OR = 12.61, 95% CI: 1.26–125.87; p = 0.0081). As expected, an older age (OR = 1.47), male gender (OR = 1.98) and comorbidities (OR = 2.52) increased the risk of being admitted to ICU or death vs more benign outpatient course. Multivariable analysis demonstrated the role of the certain genotypes (ACE2) with the severity of COVID-19 (OR: 0.31, OR 0.37 for rs2074192 and rs1978124, and OR = 2.67, OR = 2.70 for rs2106809 and rs2285666, respectively). Hardy-Weinberg equilibrium in hospitalized group for I/D SNP in ACE was not showed (p<0.05), which might be due to the association with the disease. No association between COVID-19 disease and the different AGTR1 SNPs was evidenced on multivariable, nevertheless the A/A genotype for rs5183 showed an higher hospitalization risk in patients with comorbidities. Conclusions Different genetic variants in ACE2 were associated with a severe clinical course and death groups of patients with COVID-19. ACE2 common SNPs in the population might modulate severity of COVID-19 infection independently of other known markers like gender, age and comorbidities.

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Leishmania infantum causes human and canine leishmaniosis. The parasite, transmitted by phlebotomine sand flies, infects species other than dogs and people, including wildlife, although their role as reservoirs of infection remains unknown for most species. Molecular typing of parasites to investigate genetic variability and evolutionary proximity can help understand transmission cycles and designing control strategies. We investigated Leishmania DNA variability in kinetoplast (kDNA) and internal transcribed spacer 2 (ITS2) sequences in asymptomatically infected wildlife (n = 58) and symptomatically and asymptomatically infected humans (n = 38) and dogs (n = 15) from south‐east Spain, using single nucleotide polymorphisms (SNPs) and in silico restriction fragment length polymorphism (RFLP) analyses. All ITS2 sequences (n = 76) displayed a 99%–100% nucleotide identity with a L. infantum reference sequence, except one with a 98% identity to a reference Leishmania panamensis sequence, from an Ecuadorian patient. No heterogeneity was recorded in the 73 L. infantum ITS2 sequences except for one SNP in a human parasite sequence. In contrast, kDNA analysis of 44 L. infantum sequences revealed 11 SNP genotypes (nucleotide variability up to 4.3%) and four RFLP genotypes including B, F and newly described S and T genotypes. Genotype frequency was significantly greater in symptomatic compared to asymptomatic individuals. Both methods similarly grouped parasites as predominantly or exclusively found in humans, in dogs, in wildlife or in all three of them. Accordingly, the phylogenetic analysis of kDNA sequences revealed three main clusters, two as a paraphyletic human parasites clade and a third including dogs, people and wildlife parasites. Results suggest that Leishmania infantum genetics is complex even in small geographical areas and that, probably, several independent transmission cycles take place simultaneously including some connecting animals and humans. Investigating these transmission networks may be useful in understanding the transmission dynamics, infection risk and therefore in planning L. infantum control strategies.

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Objectives We report the results of the reverse transcriptase (RT)/protease (PR) transmitted drug resistance (TDR) prevalence study in 2018, focusing on doravirine resistance-associated mutations and the differences observed when Stanford or French National Agency for AIDS Research (ANRS)/Spanish Network of AIDS Research (RIS)/IAS-USA resistance interpretation algorithms are used to describe clinically relevant resistance. Methods We used the WHO 2009 list to investigate the prevalence of NNRTI, NRTI and PI TDR, in treatment-naive HIV-1-infected patients, adding mutations E138A/G/K/Q/R, V106I, V108I, V179L, G190Q, H221Y, F227C/L/V, M230IDR, L234I, P236L and Y318F in RT. The prevalence of doravirine resistance-associated mutations, as described by Soulie et al. in 2019, was evaluated. Clinically relevant TDR was investigated using the latest versions of ANRS, RIS, IAS-USA and Stanford algorithms. Results NNRTI mutations were detected in 82 of 606 (13.5%) patients. We found 18 patients (3.0%) with NRTI mutations and 5 patients (0.8%) with PI mutations. We detected 11 patients harbouring doravirine resistance-associated mutations (prevalence of 1.8%). Furthermore, we observed important differences in clinically relevant resistance to doravirine when ANRS/RIS (0.7%), IAS-USA (0.5%) or Stanford algorithms (5.0%) were used. V106I, which was detected in 3.8% of the patients, was the main mutation driving these differences. V106I detection was not associated with any of the clinical, demographic or virological characteristics of the patients. Conclusions The prevalence of NRTI and PI TDR remains constant in Spain. Doravirine TDR is very infrequent by RIS/ANRS/IAS-USA algorithms, in contrast with results using the Stanford algorithm. Further genotype–phenotype studies are necessary to elucidate the role of V106I in doravirine resistance.

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