Diversity of fungal endophytes from mangrove plants of Santa Catarina Island, Brazil

The mangrove ecosystem plays a crucial role in preserving the biodiversity of plants, animals, and microorganisms that are essential for materials cycles. However, the exploration of endophytic fungi isolated from mangroves, particulary in Santa Catarina (SC, Brazil), remains limited. Therefore, the purpose of this study was to assess the biodiversity of endophytic fungi found in Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, and Spartina alterniflora from two mangroves on the Island of Santa Catarina: one impacted by anthropic action (Itacorubi mangrove) and the other environmentally preserved (Ratones mangrove). Samplings were carried out between January 2020 and May 2021. Fungi were isolated from leaves, stems, and roots, identified, and clustered into groups through morphological characteristics. Further, a representative strain of each group was identified through ITS1 sequencing. A total of 373 isolates were obtained from plant tissues, of which 96 and 277 isolates were obtained from Itacorubi and Ratones mangroves, respectively. Molecular identification showed that the endophytic fungal community comprised at least 19 genera. The data on fungal community diversity revealed comparable diversity indices for genera in both mangroves. However, we observed differences in the total frequency of fungal genera between impacted (27.38%) and non-impacted (72.62%) mangroves. These findings suggest that anthropic activities in and around the Santa Catarina mangroves have had negative impact on the frequency of endophytic fungi. This emphasizes the reinforcing the significance of preserving these environments to ensure the maintenance of fungal community diversity.

Cell-to-flagellum attachment and surface architecture in kinetoplastids

A key morphological feature of kinetoplastid parasites is the position and length of flagellum attachment to the cell body. This lateral attachment is mediated by the flagellum attachment zone (FAZ), a large complex cytoskeletal structure, which is essential for parasite morphogenesis and pathogenicity. Despite the complexity of the FAZ only two transmembrane proteins, FLA1 and FLA1BP, are known to interact and connect the flagellum to the cell body. Across the different kinetoplastid species, each only has a single FLA/FLABP pair, except in Trypanosoma brucei and Trypanosoma congolense where there has been an expansion of these genes. Here, we focus on the selection pressure behind the evolution of the FLA/FLABP proteins and the likely impact this will have on host-parasite interactions.

Differential expression and activity of arginine kinase between the American trypanosomatids Trypanosoma rangeli and Trypanosoma cruzi

Trypanosoma rangeli is a non-virulent hemoflagellate parasite infecting humans, wild and domestic mammals in Central and Latin America. The share of genotypic, phenotypic, and biological similarities with the virulent, human-infective T. cruzi and T. brucei, allows comparative studies on mechanisms of pathogenesis. In this study, investigation of the T. rangeli Arginine Kinase (TrAK) revealed two highly similar copies of the AK gene in this taxon, and a distinct expression profile and activity between replicative and infective forms. Although TrAK expression seems stable during epimastigotes growth, the enzymatic activity increases during the exponential growth phase and decreases from the stationary phase onwards. No differences were observed in activity or expression levels of TrAK during in vitro differentiation from epimastigotes to infective forms, and no detectable AK expression was observed for blood trypomastigotes. Overexpression of TrAK by T. rangeli showed no effects on the in vitro growth pattern, differentiation to infective forms, or infectivity to mice and triatomines. Although differences in TrAK expression and activity were observed among T. rangeli strains from distinct genetic lineages, our results indicate an up-regulation during parasite replication and putative post-translational myristoylation of this enzyme. We conclude that up-regulation of TrAK activity in epimastigotes appears to improve proliferation fitness, while reduced TrAK expression in blood trypomastigotes may be related to short-term and subpatent parasitemia in mammalian hosts.

The presence of SARS-CoV-2 RNA in human sewage in Santa Catarina, Brazil, November 2019

Human sewage from Florianopolis (Santa Catarina, Brazil) was analyzed for severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) from October 2019 until March 2020. Twenty five ml of sewage samples were clarified and viruses concentrated using a glycine buffer method coupled with polyethylene glycol precipitation, and viral RNA extracted using a commercial kit. SARS-CoV-2 RNA was detected by RT-qPCR using oligonucleotides targeting N1, S and two RdRp regions. The results of all positive samples were further confirmed by a different RT-qPCR system in an independent laboratory. S and RdRp amplicons were sequenced to confirm identity with SARS-CoV-2. Genome sequencing was performed using two strategies; a sequence-independent single-primer amplification (SISPA) approach, and by direct metagenomics using Illumina's NGS. SARS-CoV-2 RNA was detected on 27th November 2019 (5.49 ± 0.02 log₁₀ SARS-CoV-2 genome copies (GC) L^-1), detection being confirmed by an independent laboratory and genome sequencing analysis. The samples in the subsequent three events were positive by all RT-qPCR assays; these positive results were also confirmed by an independent laboratory. The average load was 5.83 ± 0.12 log₁₀ SARS-CoV-2 GC L^-1, ranging from 5.49 ± 0.02 log₁₀ GC L^-1 (27th November 2019) to 6.68 ± 0.02 log₁₀ GC L^-1 (4th March 2020). Our findings demonstrate that SARS-CoV-2 was likely circulating undetected in the community in Brazil since November 2019, earlier than the first reported case in the Americas (21st January 2020).

The presence of SARS-CoV-2 RNA in human sewage in Santa Catarina, Brazil, November 2019

Human sewage from Florianopolis (Santa Catarina, Brazil) was analyzed for severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) from October 2019 until March 2020. Twenty five ml of sewage samples were clarified and viruses concentrated using a glycine buffer method coupled with polyethylene glycol precipitation, and viral RNA extracted using a commercial kit. SARS-CoV-2 RNA was detected by RT-qPCR using oligonucleotides targeting N1, S and two RdRp regions. The results of all positive samples were further confirmed by a different RT-qPCR system in an independent laboratory. S and RdRp amplicons were sequenced to confirm identity with SARS-CoV-2. Genome sequencing was performed using two strategies; a sequence-independent single-primer amplification (SISPA) approach, and by direct metagenomics using Illumina's NGS. SARS-CoV-2 RNA was detected on 27th November 2019 (5.49 ± 0.02 log₁₀ SARS-CoV-2 genome copies (GC) L^-1), detection being confirmed by an independent laboratory and genome sequencing analysis. The samples in the subsequent three events were positive by all RT-qPCR assays; these positive results were also confirmed by an independent laboratory. The average load was 5.83 ± 0.12 log₁₀ SARS-CoV-2 GC L^-1, ranging from 5.49 ± 0.02 log₁₀ GC L^-1 (27th November 2019) to 6.68 ± 0.02 log₁₀ GC L^-1 (4th March 2020). Our findings demonstrate that SARS-CoV-2 was likely circulating undetected in the community in Brazil since November 2019, earlier than the first reported case in the Americas (21st January 2020).

First case of canine visceral leishmaniasis in the midwestern of Santa Catarina State, Brazil

Canine visceral leishmaniasis (CVL) caused by Leishmania (Leishmania) infantum is transmitted by phlebotomine sandflies and a major zoonotic disease in Brazil. Due to the southward expansion of the disease within the country and the central role of dogs as urban reservoirs of the parasite, we have investigated the occurrence of CVL in two municipalities Erval Velho and Herval d'Oeste in the Midwest region of Santa Catarina state. Peripheral blood samples from 126 dogs were collected in both cities and tested for anti-L. infantum antibodies by indirect enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence reaction (IIF) and for the presence of parasite DNA by polymerase chain reaction (PCR) in peripheral blood. From examined dogs, 35.71% (45/126) were positive for at least one of the three tests and two (1.6%) were positive in all performed tests. Twelve dogs (9.5%) were positive for both ELISA and IIF, while 21 dogs were exclusively positive for ELISA (16.7%), and 15 (11.9%) for IIF. L. infantum k-DNA was detected by PCR in 9 out of 126 dogs (7.1%) and clinical symptoms compatible with CVL were observed for 6 dogs. Taken together, these results indicate the transmission of CVL in this region, highlighting the needs for epidemiological surveillance and implementation of control measures for CVL transmission in this region.

Immunochromatography and laboratory serologies: an evaluation of immunodiagnoses in prenatal care

OBJECTIVES

to describe the use of affinity chromatographies and laboratory serologies in the evaluation of immunodiagnoses during prenatal.

METHODS

quantitative study, characterized as a descriptive observational research. Data was collected from the records of 46 pregnant women who were in prenatal follow up in the Primary Health Care in a capital in the South of Brazil. The data found was codified and analyzed using descriptive statistics.

RESULTS

a mean of 43.1 days was found to take place between the request of laboratory serology and the evaluation by a professional. It was also found that 21.7% of pregnant women did not collect the serologies requested during the first prenatal consultation, and that the affinity chromatographies were only applied in 10.8% of the participants.

CONCLUSIONS

in spite of the studies for the improvement of prenatal consultations, for the provision of new technologies and for the permanent education offered to the professionals, there are still questions that make the actual implementation of affinity chromatographies more difficult.

Swab pooling: A new method for large-scale RT-qPCR screening of SARS-CoV-2 avoiding sample dilution

To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling of equal volumes from individually collected samples. Paired analysis of pooled and individual samples from 613 patients revealed 94 positive individuals. Having individual testing as reference, no false-positives or false-negatives were observed for swab pooling. In additional 18,922 patients screened with swab pooling (1,344 pools), mean Cq differences between individual and pool samples ranged from 0.1 (Cr.I. -0.98 to 1.17) to 2.09 (Cr.I. 1.24 to 2.94). Overall, 19,535 asymptomatic patients were screened using 4,400 RT-qPCR assays. This corresponds to an increase of 4.4 times in laboratory capacity and a reduction of 77% in required tests. Therefore, swab pooling represents a major alternative for reliable and large-scale screening of SARS-CoV-2 in low prevalence populations.

Extremophile Microbial Communities and Enzymes for Bioenergetic Application Based on Multi-Omics Tools

Abstract: Genomic and proteomic advances in extremophile microorganism studies are increasingly demonstrating their ability to produce a variety of enzymes capable of converting biomass into bioenergy. Such microorganisms are found in environments with nutritional restrictions, anaerobic environments, high salinity, varying pH conditions and extreme natural environments such as hydrothermal vents, soda lakes, and Antarctic sediments. As extremophile microorganisms and their enzymes are found in widely disparate locations, they generate new possibilities and opportunities to explore biotechnological prospecting, including biofuels (biogas, hydrogen and ethanol) with an aim toward using multi-omics tools that shed light on biotechnological breakthroughs.

Messenger RNA levels of the Polo-like kinase gene (PLK) correlate with cytokinesis in the Trypanosoma rangeli cell cycle

BACKGROUND

Trypanosoma rangeli is a protozoan parasite that is non-virulent to the mammalian host and is morphologically and genomically related to Trypanosoma cruzi, whose proliferation within the mammalian host is controversially discussed.

OBJECTIVES

We aimed to investigate the T. rangeli cell cycle in vitro and in vivo by characterizing the timespan of the parasite life cycle and by proposing a molecular marker to assess cytokinesis.

METHODOLOGY

The morphological events and their timing during the cell cycle of T. rangeli epimastigotes were assessed using DNA staining, flagellum labelling and bromodeoxyuridine incorporation. Messenger RNA levels of four genes previously associated with the cell cycle of trypanosomatids (AUK1, PLK, MOB1 and TRACK) were evaluated in the different T. rangeli forms.

FINDINGS

T. rangeli epimastigotes completed the cell cycle in vitro in 20.8 h. PLK emerged as a potential molecular marker for cell division, as its mRNA levels were significantly increased in exponentially growing epimastigotes compared with growth-arrested parasites or in vitro-differentiated trypomastigotes. PLK expression in T. rangeli can be detected near the flagellum protrusion site, reinforcing its role in the cell cycle. Interestingly, T. rangeli bloodstream trypomastigotes exhibited very low mRNA levels of PLK and were almost entirely composed of parasites in G1 phase.

MAIN CONCLUSIONS

Our work is the first to describe the T. rangeli cell cycle in vitro and proposes that PLK mRNA levels could be a useful tool to investigate the T. rangeli ability to proliferate within the mammalian host bloodstream.

Cryptic species and genetic structure in Didemnum granulatum Tokioka, 1954 (Tunicata: Ascidiacea) from the southern Brazilian coast

Didemnum granulatum is a colonial fouling ascidian that lives in subtidal substrates, worldwide. It exhibits two morphotypes, orange and beige. In this study, we verified if the color morphotypes and/or the spatial distribution of specimens in different islands might be associated to patterns of genetic structure of a single species, or if they represent distinct cryptic species. Specimens were collected in four islands, along the coast of the Santa Catarina state. A segment of 490 bp from the mitochondrial gene cytochrome c oxidase subunit 1 (COI) was amplified from 45 samples. Twenty-one haplotypes were identified. The total haplotype diversity (0.912) and the total nucleotide diversity (0.044) were high. The global Fst of the populations analyzed was 0.97, with most of the variation occurring between orange and beige groups (82.19%). The variation found between populations within groups was 15.37%, and 2.45% within populations. Haplotype networks and the neighbor-joining tree showed clear genetic divergence between individuals of distinct colors, and between the islands. These evidences strongly support the presence of a complex of two cryptic species for D. granulatum occupying the studied area. Both species were also highly genetically structured between islands, suggesting that the conservation process of these populations is complex.

Genome of the avirulent human-infective trypanosome--Trypanosoma rangeli

Background

Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.

Methodology/Principal Findings

The T. rangeli haploid genome is ∼24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heat-shock proteins.

Conclusions/Significance

Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets.

Comparative genomics is a powerful tool that affords detailed study of the genetic and evolutionary basis for aspects of lifecycles and pathologies caused by phylogenetically related pathogens. The reference genome sequences of three trypanosomatids, T. brucei, T. cruzi and L. major, and subsequent addition of multiple Leishmania and Trypanosoma genomes has provided data upon which large-scale investigations delineating the complex systems biology of these human parasites has been built. Here, we compare the annotated genome sequence of T. rangeli strain SC-58 to available genomic sequence and annotation data from related species. We provide analysis of gene content, genome architecture and key characteristics associated with the biology of this non-pathogenic trypanosome. Moreover, we report striking new genomic features of T. rangeli compared with its closest relative, T. cruzi, such as (1) considerably less amplification on the gene copy number within multigene virulence factor families such as MASPs, trans-sialidases and mucins; (2) a reduced repertoire of genes encoding anti-oxidant defense enzymes; and (3) the presence of vestigial orthologs of the RNAi machinery, which are insufficient to constitute a functional pathway. Overall, the genome of T. rangeli provides for a much better understanding of the identity, evolution, regulation and function of trypanosome virulence determinants for both mammalian host and insect vector.

The genome of Anopheles darlingi, the main neotropical malaria vector

Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector–human and vector–parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi.

Trypanosoma rangeli protein tyrosine phosphatase is associated with the parasite's flagellum

Protein tyrosine phosphatases (PTPs) play an essential role in the regulation of cell differentiation in pathogenic trypanosomatids. In this study, we describe a PTP expressed by the non-pathogenic protozoan Trypanosoma rangeli (TrPTP2). The gene for this PTP is orthologous to the T. brucei TbPTP1 and Trypanosoma cruzi (TcPTP2) genes. Cloning and expression of the TrPTP2 and TcPTP2 proteins allowed anti-PTP2 monoclonal antibodies to be generated in BALB/c mice. When expressed by T. rangeli epimastigotes and trypomastigotes, native TrPTP2 is detected as a ~65 kDa protein associated with the parasite's flagellum. Given that the flagellum is an important structure for cell differentiation in trypanosomatids, the presence of a protein responsible for tyrosine dephosphorylation in the T. rangeli flagellum could represent an interesting mechanism of regulation in this structure.

Trypanosoma rangeli expresses a β-galactofuranosyl transferase

Glycoconjugates play essential roles in cell recognition, infectivity and survival of protozoan parasites within their insect vectors and mammalian hosts. β-galactofuranose is a component of several glycoconjugates in many organisms, including a variety of trypanosomatids, but is absent in mammalian and African trypanosomes. Herein, we describe the presence of a β(1-3) galactofuranosyl transferase (GALFT), an important enzyme of the galactofuranose biosynthetic pathway, in Trypanosoma rangeli. The T. rangeli GALFT gene (TrGALFT) has an ORF of 1.2 Kb and is organized in two copies in the T. rangeli genome. Antibodies raised against an internal fragment of the transferase demonstrated a 45 kDa protein coded by TrGALFT was localized in the whole cytoplasm, mainly in the Golgi apparatus and equally expressed in epimastigotes and trypomastigotes from T. rangeli. Despite the high sequence similarity with Trypanosoma cruzi and Leishmania spp. orthologous TrGALFT showed a substitution of the metal-binding DXD motif, conserved amongst glycosyltransferases, for a DXE functionally analogous motif. Moreover, a reduced number of GALFT genes were present in T. rangeli when compared with other pathogenic kinetoplastid species.

In vitro antiherpes effects of a C-glycosylflavonoid-enriched fraction of Cecropia glaziovii Sneth

AIMS

To investigate the in vitro antiherpes effects of the crude aqueous extract obtained from Cecropia glaziovii leaves and their related fractions, the n-butanol fraction (n-BuOH) and the C-glycosylflavonoid-enriched fraction (MeOH(AMB)), and to determine the viral multiplication step(s) upon which this C-glycosylflavonoid-enriched fraction acts.

METHODS AND RESULTS

The antiviral activity was evaluated against human herpes virus types 1 and 2 (HHV-1, HHV-2) by plaque reduction assay. The mode of action of the most active fraction was investigated by a set of assays, and the results demonstrated that MeOH(AMB) fraction exerts anti-herpes action by the reduction of viral infectivity (only against HHV-2); by the inhibition of virus entry into cells; by the inhibition of cell-to-cell virus spread as well as by the impaired levels of envelope proteins of HHV-1. The high-performance liquid chromatography (HPLC)-photo-diode array (PDA) analysis showed that the C-glycosylflavonoids are the major constituents of this fraction.

CONCLUSIONS

These data showed that the MeOH(AMB) fraction has an antiviral activity against HHV types 1 and 2. The C-glycosylflavonoids are the major constituents of this fraction, which suggests that they could be one of the compounds responsible for the detected anti-herpes activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The MeOH(AMB) fraction can be regarded as a phytopharmaceutical candidate for the treatment of herpetic infections.

Characterization of Trypanosoma cruzi isolated from humans, vectors, and animal reservoirs following an outbreak of acute human Chagas disease in Santa Catarina State, Brazil

During March 2005, 24 cases of acute human Chagas disease were detected in Santa Catarina State, southern Brazil, all of them related to the ingestion of Trypanosoma cruzi-contaminated sugar cane juice. Following field studies allowed the isolation of 13 T. cruzi strains from humans, opossums (Didelphis aurita and Didelphis albiventris), and vectors (Triatoma tibiamaculata). The isolated strains were characterized by multilocus enzyme electrophoresis (MLEE) and analysis of the spliced-leader and 24Salpha rRNA genes. The assays revealed that all strains isolated from humans belong to the TcII group but revealed a TcII variant pattern for the phosphoglucomutase enzyme. Strains isolated from opossums also showed a TcI profile in all analysis, but strains isolated from triatomines revealed a mixed TcI/TcII profile by MLEE. No indication of the presence of Trypanosoma rangeli was observed in any assay. Considering that mixed strains (TcI/TcII) were isolated from triatomines in an area without active vectorial transmission to humans and that all strains isolated from humans belong to the TcII group, our results show that T. cruzi TcI and TcII groups are circulating among reservoirs and vectors in southern Brazil and indicate that selection toward TcII group in humans may occur after ingestion of a mixed (TcI/TcII) T. cruzi population.