SARS-CoV-2 Seroconversion in Response to Infection and Vaccination: a Time Series Local Study in Brazil.

The investigation of antibodies raised against different severe acute respiratory syndrome coronavirus (SARS-CoV-2) antigens can help to determine the extent of previous SARS-CoV-2 infections in the population and track the humoral response to vaccination. Therefore, serological surveys can provide key information to better manage the pandemic and/or to implement the most effective vaccination program. Here we describe a time series anti-nucleocapsid, anti-spike IgG serological survey analysis in the city of Matinhos, PR, Brazil during the year of 2021. Seroconversion rates to the nucleocapsid antigen were not influenced by gender or age. The serological data support that the coronavirus disease 2019 (COVID-19) infection rate is ~50% higher than official numbers. Furthermore, by applying serological data, the corrected infection fatality rate was estimated to be lower than 2.4% in contrast with the official estimative of 3.6%. The rates of IgG reactive to spike antigen resembled the curve of the fraction the population that had taken the second vaccine dose. Up to 82% of spike seroconversion was detected in the end of 2021, confirming the effectiveness of the COVID-19 vaccination program in the city. This SARS-CoV-2 serological study unraveled the SARS-CoV-2 infection rates and the response to vaccination in the city of Matinhos. IMPORTANCE The investigation of antibodies raised against SARS-CoV-2 can help to determine the extent of previous SARS-CoV-2 infections and track the humoral response to vaccination. Here we describe a time series anti-nucleocapsid, anti-spike IgG serological survey in the city of Matinhos, PR, Brazil during the year of 2021. The data depicted the progression of SARS-CoV-2 infections in the city allowing the correction of the number of citizens who experienced COVID-19 and the disease fatality rate. The seroconversion rates to the spike antigen resembled the curve of the fraction of the population that had taken the second vaccine dose, thereby confirming the effectiveness of the COVID-19 vaccination program in the city.

Biomolecular engineering of antidehydroepiandrosterone antibodies: a new perspective in cancer diagnosis and treatment using single-chain antibody variable fragment.

AIM: To develop a monoclonal antibody against dehydroepiandrosterone (DHEA) and miniaturize it, generating a single-chain antibody variable fragment (scFv) against DHEA as an adrenocortical carcinoma (ACC) marker. MATERIAL & METHODS: DHEA conjugated to keyhole limpet hemocyanin was used as an immunogen to obtain anti-DHEA hybridomas. Variable fragments were cloned from hybridoma 5B7 total RNA, and used to detect DHEA in normal adrenal tissue and ACC cells. RESULTS: IgM monoclonal antibody was highly specific, and the recombinant scFv preserved parental antibody characteristics, allowing tissue localization of DHEA. CONCLUSION: Undefined small lesions are challenges for clinicians and impact clinical adrenocortical tumor management. Generating an anti-DHEA scFv facilitates development of imaging tests for early diagnosis of pediatric ACC.

STAT3 polymorphism and Helicobacter pylori CagA strains with higher number of EPIYA-C segments independently increase the risk of gastric cancer.

BACKGROUND: Because to date there is no available study on STAT3 polymorphism and gastric cancer in Western populations and taking into account that Helicobacter pylori CagA EPIYA-C segment deregulates SHP-2/ERK-JAK/STAT3 pathways, we evaluated whether the two variables are independently associated with gastric cancer. METHODS: We included 1048 subjects: H. pylori-positive patients with gastric carcinoma (n = 232) and with gastritis (n = 275) and 541 blood donors. Data were analyzed using logistic regression model. RESULTS: The rs744166 polymorphic G allele (p = 0.01; OR = 1.76; 95 % CI = 1.44-2.70), and CagA-positive (OR = 12.80; 95 % CI = 5.58-19.86) status were independently associated with gastric cancer in comparison with blood donors. The rs744166 polymorphism (p = 0.001; OR = 1.64; 95 % CI = 1.16-2.31) and infection with H. pylori CagA-positive strains possessing higher number of EPIYA-C segments (p = 0.001; OR = 2.28; 95 % CI = 1.41-3.68) were independently associated with gastric cancer in comparison with gastritis. The association was stronger when host and bacterium genotypes were combined (p < 0.001; OR = 3.01; 95 % CI = 2.29-3.98). When stimulated with LPS (lipopolysaccharide) or Pam3Cys, peripheral mononuclear cells of healthy carriers of the rs744166 GG and AG genotypes expressed higher levels of STAT3 mRNA than those carrying AA genotype (p = 0.04 for both). The nuclear expression of phosphorylated p-STAT3 protein was significantly higher in the antral gastric tissue of carriers of rs744166 GG genotype than in carriers of AG and AA genotypes. CONCLUSIONS: Our study provides evidence that STAT3 rs744166 G allele and infection with CagA-positive H. pylori with higher number of EPIYA-C segments are independent risk factors for gastric cancer. The odds ratio of having gastric cancer was greater when bacterium and host high risk genotypes were combined.

Analysis of the oxidase activity induced by CCl(4) and H(2)O(2) in different recombinant myoglobins.

Hemoproteins may present several functions due to their prosthetic groups. After a long time, well-studied proteins such as myoglobin have surprised us with new functions. Myoglobin is a hemoprotein which has some well described and unexpected functions within the organism. Oxidase activity in standard myoglobins has been described and this activity was attributed to a covalent linkage between heme and some amino acid residues such as histidine, when myoglobins are treated with alkyl halides, and tyrosine, and when myoglobins are treated with H(2)O(2). We have found that the oxidase activity, due to H(2)O(2) treatment, can appear in different myoglobins, which presents no key residue, such as Tyr 103, for the oxidase activity previously described in the literature.

Size polymorphism in alleles of the myoglobin gene from biomphalaria mollusks.

Introns are common among all eukaryotes, while only a limited number of introns are found in prokaryotes. Globin and globin-like proteins are widely distributed in nature, being found even in prokaryotes and a wide range of patterns of intron-exon have been reported in several eukaryotic globin genes. Globin genes in invertebrates show considerable variation in the positions of introns; globins can be found without introns, with only one intron or with three introns in different positions. In this work we analyzed the introns in the myoglobin gene from Biomphalaria glabrata, B. straminea and B. tenagophila. In the Biomphalaria genus, the myoglobin gene has three introns; these were amplified by PCR and analyzed by PCR-RFLP. Results showed that the size (number or nucleotides) and the nucleotide sequence of the coding gene of the myoglobin are variable in the three species. We observed the presence of size polymorphisms in intron 2 and 3; this characterizes a homozygous/heterozygous profile and it indicates the existence of two alleles which are different in size in each species of Biomphalaria. This polymorphism could be explored for specific identification of Biomphalaria individuals.

Debaryomyces hansenii UFV-1 intracellular alpha-galactosidase characterization and comparative studies with the extracellular enzyme.

Debaryomyces hansenii cells cultivated on galactose produced extracellular and intracellular alpha-galactosidases, which showed 54.5 and 54.8 kDa molecular mass (MALDI-TOF), 60 and 61 kDa (SDS-PAGE) and 5.15 and 4.15 pI values, respectively. The extracellular and intracellular deglycosylated forms presented 36 and 40 kDa molecular mass, with 40 and 34% carbohydrate content, respectively. The N-terminal sequences of the alpha-galactosidases were identical. Intracellular alpha-galactosidase showed smaller thermostability when compared to the extracellular enzyme. D. hansenii UFV-1 extracellular alpha-galactosidase presented higher kcat than the intracellular enzyme (7.16 vs 3.29 s-1, respectively) for the p-nitrophenyl-alpha-D-galactopyranoside substrate. The Km for hydrolysis of pNPalphaGal, melibiose, stachyose, and raffinose were 0.32, 2.12, 10.8, and 32.8 mM, respectively. The intracellular enzyme was a competitively inhibited by galactose (Ki = 0.70 mM), and it was inactivated by Cu(II) and Ag(I). Enzyme incubation with soy milk for 6 h at 55 degrees C reduced stachyose and raffinose amounts by 100 and 73%, respectively.