A cold wave of winter 2021 in central South America: characteristics and impacts.

During the austral winter (June-August) of 2021, the meteorological services of Brazil, Argentina, Peru, Paraguay, Bolivia, and Chile all issued forecasts for unusually cold conditions. Record-low minimum temperatures and cold spells were documented, including one strong cold wave episode that affected 5 countries. In this study, we define a cold wave as a period in which daily maximum and minimum air temperatures are below the corresponding climatological 10th percentile for three or more consecutive days. The intense cold wave event in the last week of June, 2021, resulted in record-breaking minimum daily temperatures in several places in central South America and Chile. Several locations had temperatures about 10 °C below average, central South America had freezing conditions, and southern Brazil even saw snow. The cold air surge was characterized by an intense upper-air trough located close to 35° S and 70° W. The southerly flow to the west of this trough brought very cold air northward into subtropical and tropical South America. A northward flow between the lower-level cyclonic and anticyclonic perturbations caused the intense southerly flow between the upper-level ridge and trough. This condition facilitated the inflow of near-surface cold air from southern Argentina into southeastern Brazil and tropical South America east of the Andes. In the city of São Paulo, the cold wave caused the death of 13 homeless people from hypothermia. Frost and snow across southern and southeastern Brazil caused significant damage to coffee, sugarcane, oranges, grapes, and other fruit and vegetable crops. Wine and coffee production fell, the latter by 30%, and prices of food and commodities in the region rose. Supplementary Information: The online version contains supplementary material available at 10.1007/s00382-023-06701-1.

Discovery and characterization of new microsatellite loci in Dipteryx alata Vogel (Fabaceae) using next-generation sequencing data.

The use of next-generation sequencing (NGS) technologies provides a great volume of genome sequence data even for non-model species. The development of microsatellite markers using these data is a relatively quick and easy process. Dipteryx alata Vogel (Fabaceae) is an arboreal species from the Cerrado biome and is considered an important plant genetic resource. Here, we report the development of microsatellite markers for D. alata using NGS data. DNA samples from four individuals were sequenced using the Illumina MiSeq platform and high-quality reads were assembled into contigs of the D. alata genome sequence. Microsatellite regions were identified using the IMEX webserver and primer pairs were designed using the Primer3 software. The amplification settings for each locus were optimized. Fluorescent-labeled primers were developed and used to genotype individuals derived from three natural populations of D. alata. Fifty-four microsatellite regions were identified, from which 27 were elected to primer design. Among the amplified loci, 11 were polymorphic, with the number of alleles ranging from 2 to 10. The expected heterozygosity under Hardy-Weinberg Equilibrium (HWE) per locus varied from 0.191 to 0.807. Genotype and allele frequencies for all loci agreed with those expected under HWE and linkage disequilibrium was not significant for all pairs of loci. The probabilities of exclusion of paternity and of combined identity were equal to 0.993 and 5.65 x 10-8, respectively. The markers developed in this study are useful to several types of population genetic studies with D. alata and, eventually, for closely related species.

Genomewide single nucleotide polymorphism discovery in Atlantic salmon (Salmo salar): validation in wild and farmed American and European populations.

A considerable number of single nucleotide polymorphisms (SNPs) are required to elucidate genotype-phenotype associations and determine the molecular basis of important traits. In this work, we carried out de novo SNP discovery accounting for both genome duplication and genetic variation from American and European salmon populations. A total of 9 736 473 nonredundant SNPs were identified across a set of 20 fish by whole-genome sequencing. After applying six bioinformatic filtering steps, 200 K SNPs were selected to develop an Affymetrix Axiom(®) myDesign Custom Array. This array was used to genotype 480 fish representing wild and farmed salmon from Europe, North America and Chile. A total of 159 099 (79.6%) SNPs were validated as high quality based on clustering properties. A total of 151 509 validated SNPs showed a unique position in the genome. When comparing these SNPs against 238 572 markers currently available in two other Atlantic salmon arrays, only 4.6% of the SNP overlapped with the panel developed in this study. This novel high-density SNP panel will be very useful for the dissection of economically and ecologically relevant traits, enhancing breeding programmes through genomic selection as well as supporting genetic studies in both wild and farmed populations of Atlantic salmon using high-resolution genomewide information.

Control of resin production in Araucaria angustifolia, an ancient South American conifer.

Araucaria angustifolia is an ancient slow-growing conifer that characterises parts of the Southern Atlantic Forest biome, currently listed as a critically endangered species. The species also produces bark resin, although the factors controlling its resinosis are largely unknown. To better understand this defence-related process, we examined the resin exudation response of A. angustifolia upon treatment with well-known chemical stimulators used in fast-growing conifers producing both bark and wood resin, such as Pinus elliottii. The initial hypothesis was that A. angustifolia would display significant differences in the regulation of resinosis. The effect of Ethrel(®) (ET - ethylene precursor), salicylic acid (SA), jasmonic acid (JA), sulphuric acid (SuA) and sodium nitroprusside (SNP - nitric oxide donor) on resin yield and composition in young plants of A. angustifolia was examined. In at least one of the concentrations tested, and frequently in more than one, an aqueous glycerol solution applied on fresh wound sites of the stem with one or more of the adjuvants examined promoted an increase in resin yield, as well as monoterpene concentration (α-pinene, ß-pinene, camphene and limonene). Higher yields and longer exudation periods were observed with JA and ET, another feature shared with Pinus resinosis. The results suggest that resinosis control is similar in Araucaria and Pinus. In addition, A. angustifolia resin may be a relevant source of valuable terpene chemicals, whose production may be increased by using stimulating pastes containing the identified adjuvants.

A sensitive and robust method for automated on-line monitoring of enzymatic activities in water and water resources.

The realisation of a novel concept for automated on-line monitoring of enzymatic activities in water was successfully demonstrated by long-term field testing at two remote Austrian ground water resources. The ß-D-glucuronidase (GLUC) activity was selected as a representative enzymatic model parameter for the on-line determination. But the device can be adapted for any enzymatic reaction with diagnostic relevance for microbial water quality monitoring, as demonstrated for the ß-D-galactosidase activity. Automated filtration of volumes up to 5 litres supports sensitive quantification of enzymatic activities. Internet-based data transfer, using internal control parameters for verification and a dynamic determination of the limit of quantification, enabled robust enzymatic on-line monitoring during a 2-year period. A proportion of 5,313 out of 5,506 GLUC activity measurements (96.5%) could be positively verified. Hydrological (discharge, gauge, turbidity, temperature, pH, electric conductivity, spectral absorbance coefficient at 254 nm) as well as microbiological parameters (Escherichia coli, coliforms) were concurrently determined to characterise the investigated ground water resources. The enzymatic on-line measurements closely reflected the different hydrological conditions and contamination patterns of the test sites. Contrary to expectations, GLUC did not qualify as a proxy-parameter for the occurrence of cultivation-based E. coli contamination and warrants further detailed investigations on its indication capacity as a rapid means for microbial faecal pollution detection in such aquatic habitats. Microbial on-line monitoring is likely to become more important in the future, complementing existing surveillance strategies for water safety management. Further perspectives on the application of such analytical on-line technologies, such as their connection with event-triggered sampling and standardised diagnostics, are discussed.

Characterization of Mycobacterium salmoniphilum as causal agent of mycobacteriosis in Atlantic salmon, Salmo salar L., from a freshwater recirculation system.

Thirty Atlantic salmon, Salmo salar L., with low corporal condition relative to other fish present in the culture system, were sampled from a freshwater recirculation pisciculture located in Chile. The most characteristic signs and lesions were cachexia and presence of multiple greyish-white granulomas within internal organs. The external and internal lesions, along with the microscopic, histologic and biochemical findings, were consistent with mycobacteriosis. The identification of Mycobacterium salmoniphilum as the causal agent of the lesions was possible through the use of molecular analyses. This study represents the first report of Mycobacterium salmoniphilum in a freshwater recirculation system and the first case of fish mycobacteriosis described in Chile.

Relationship between splenic sequestration and thrombocytopenia in Trypanosoma evansi infection in rats.

Trypanosoma evansi infections in domestic animals are characterized by anemia and thrombocytopenia. The cause of the platelets decrease is unknown, but researchers suggest that thrombocytopenia may result from damage of the bone marrow, reduced survival of platelets, auto-immune thrombocytopenia, disseminated intravascular coagulation and splenic sequestration. Some of these causes have already been tested by our research group and found to be unrelated. Therefore, this study has the objective of testing the hypothesis that splenic sequestration might be responsible for thrombocytopenia in T. evansi-infected rats. A total of 28 rats assigned to four groups were used in the experiment. Group A rats were splenectomized and infected with T. evansi, group B rats were infected with T. evansi, group C rats were splenectomized, but not infected and group D rats were normal controls. Five days post-infection all rats were anesthetized and blood was collected in order to measure the number of circulating platelets, fibrinogen levels, prothrombin time (PT) and activated partial thromboplastin time (aPTT). The spleens of groups B and D were weighed at necropsy. The infected animals (groups A and B) showed a significant reduction in platelets and increased PT and aPTT when compared to negative control groups (groups C and D). Animals from group A showed increased levels of fibrinogen. The mean weight of spleen differed between group B (2.62g) and group D (0.55g). It was concluded that there is no relationship between thrombocytopenia and splenic sequestration in infection by T. evansi.

Detection of a new mumps virus genotype during parotitis epidemic of 2006-2007 in the state of São Paulo, Brazil.

Nucleotide sequence analyses of the SH gene of 18 mumps virus isolates collected in the 2006-2007 parotitis epidemic in the state of São Paulo identified a new genotype, designated genotype M. This new designation fulfills all the parameters required to define a new mumps virus genotype. The parameters were established by an expert panel in collaboration with the World Health Organization (WHO) in 2005. This information will enhance the mumps virus surveillance program both at the national and global levels.

The retinoblastoma gene is involved in malignant progression of astrocytomas.

Loss of chromosome 13q occurs in up to 50% of human astrocytomas, suggesting the presence of an astrocytoma tumor suppressor gene on that chromosome. To determine whether the retinoblastoma susceptibility gene (Rb) on 13q14 contributes to the formation of astrocytomas, we examined 85 tumors for loss of heterozygosity (LOH) at the intragenic Rb 1.20 locus. LOH was detected in 16 of 54 informative high-grade astrocytomas (30%), but was not detected in 12 low-grade gliomas. Deletion mapping with flanking markers on 13q revealed that the Rb 1.20 region was preferentially targeted by the deletions. Tumors with LOH at Rb 1.20 were examined for mutations in the remaining Rb allele using single-strand conformational polymorphism (SSCP) analysis and direct DNA sequencing. Mutations were detected in exon 8 (1 tumor), exon 24 (2 tumors), and intron 24 (1 tumor). Rb protein expression, as assessed by immunohistochemistry, was altered in 3 of 9 cases with LOH and in 1 tumor without LOH. Our results demonstrate that Rb inactivation contributes to the formation of high-grade astrocytomas, and therefore implicate a second, known tumor suppressor gene in astrocytoma tumorigenesis.

MTS1/CDKN2 gene mutations are rare in primary human astrocytomas with allelic loss of chromosome 9p.

Human astrocytomas frequently have allelic losses of chromosome 9p, suggesting the presence of a 9p astrocytoma tumor suppressor gene. The MTS1 (or CDKN2) gene on chromosome 9p encodes a cell-cycle regulator and is deleted in approximately 80% of astrocytoma cell lines. To determine whether MTS1 is the tumor suppressor gene involved in human astrocytoma formation in vivo, we have analyzed chromosome 9p allelic loss and the MTS1 gene in 30 primary astrocytomas. Deletion mapping demonstrated 15 cases with allelic loss of chromosome 9p, with all losses either flanking or involving the MTS1 gene. Direct analysis of the MTS1 gene, however, revealed only a single missense mutation in a high-grade tumor that had lost the second allele. The low frequency of MTS1 mutations in primary astrocytomas with allelic 9p loss suggests that MTS1 may be more important for in vitro than in vivo astrocytoma growth, and that another 9p tumor suppressor gene may be involved in astrocytoma formation in vivo. Analysis of the MTS1 gene also demonstrated two intragenic polymorphisms, one in exon 2 and one in the 3' untranslated region, that can be used to assay allelic loss directly at MTS1.

The putative glioma tumor suppressor gene on chromosome 19q maps between APOC2 and HRC.

The frequent allelic loss of chromosome 19q in human gliomas suggests that 19q harbors a tumor suppressor gene that is integral to glioma tumorigenesis. Our initial deletion mapping of this gene localized the common region of deletion to the distal long arm, 19q13.2-13.4. To bracket the putative tumor suppressor gene further, we have studied this region in 55 gliomas, using loss of heterozygosity studies for 11 well mapped, highly informative microsatellite polymorphisms that cover this area: D19S178; BCL3; APOC2; ERCC1; DM; D19S112; HRC; D19S246; KLK; D19S180; and D19S254 (from centromeric to telomeric). Twenty astrocytic, oligodendroglial, and mixed gliomas had deletions affecting this region. Of nine partial deletions, two cases maintained heterozygosity at APOC2 while showing allelic loss at the more telomeric markers, ERCC1 and DM, while five cases maintained heterozygosity at HRC but lost the more centromeric markers, D19S112 and DM. Nine cases lost the entire D19S178 to D19S254 region. Three astrocytic gliomas, including one with an interstitial deletion, had terminal deletions of 19q13.4. The minimum area of overlap shared by the interstitial deletions is between APOC2 and HRC, including ERCC1, DM, and D19S112. These findings suggest that the glioma tumor suppressor gene maps to an approximately 8-cM/5-megabase region on 19q13.2-13.3 between the proximal marker APOC2 and the distal marker HRC. Among the DNA repair/DNA metabolism genes on chromosome 19q, ERCC1, LIG1, and perhaps ERCC2 are within the common area of deletion; XRCC1 is centromeric and is therefore excluded as a candidate.

Analysis of the neurofibromatosis 2 gene in human ependymomas and astrocytomas.

Ependymomas and astrocytomas commonly have allelic losses of chromosome 22q, which suggests the presence of a glioma tumor suppressor gene on 22q. A candidate tumor suppressor gene on 22q is the neurofibromatosis 2 (NF2) gene since NF2 patients have an increased susceptibility to ependymomas and astrocytomas. Using single strand conformation polymorphism analysis and direct DNA sequencing, we screened 8 ependymomas and 30 fibrillary astrocytomas from non-NF2 patients for mutations in the coding sequence and portions of the 3' untranslated region of the NF2 gene. Only one mutation was detected, a single base deletion in NF2 exon 7 from a spinal ependymoma, which had also lost the wild-type allele. These results suggest that the NF2 gene may be important in the formation of some ependymomas but the NF2 gene is probably not the critical chromosome 22q tumor suppressor gene involved in astrocytoma tumorigenesis.

Molecular genetics of pediatric brain stem gliomas. Application of PCR techniques to small and archival brain tumor specimens.

Brain stem gliomas are pediatric astrocytomas that histologically resemble adult supratentorial astrocytomas such as glioblastomas multiforme (GBM). Our molecular genetic studies have suggested that adult GBM can be divided into two genetic subsets: tumors with p53 tumor suppressor gene mutations and chromosome 17p loss that occur more commonly in younger patients; and tumors with epidermal growth factor receptor (EGFR) gene amplification that occur more commonly in older patients. Brain stem gliomas have not been studied since biopsies of these tumors are rare and extremely small. We investigated the molecular genetic composition of seven brain stem glioblastomas (two small biopsies, five autopsies) using polymerase chain reaction (PCR) assays for chromosomal loss, gene mutation and gene amplification. Four cases lost portions of chromosome 17p that included the p53 gene. These four cases and one additional case had mutations in the p53 gene. None of the cases showed amplification of the EGFR gene. Allelic losses of the long arm of chromosome 10 were noted in four cases. These results suggest similarities between pediatric brain stem glioblastomas and those GBM that occur in younger adult patients, and confirm the utility of PCR-based means of studying small and archival brain tumor specimens.