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OTA Vertical File by Author
No full textThis document presents different types of OTA publications by author
Ecology of A.carbonarius and ochratoxin A production in vine fruits and control in the production chain
No full textThis study examined black aspergilli, especially A. carbonarius and A. niger and
ochratoxin A (OTA) contamination of grapes, during drying and industrial processing
of dried vine fruits. This was complemented by studies on potential control using
preservatives and physical factors such as modified atmospheres. Fungal population
kinetics were determined in relation to grapes at harvest, and during drying at three
different altitudes (sea level: 0-200 m; medium level: 250-500 m; high level: >500 m)
in two seasons. At pre-harvest, A. niger aggregate species were the predominant
fungal species while A. carbonarius was occasionally isolated, in both years studied.
Both altitude and bunch position affected black aspergilli population dynamics.
Overall, they were increased during drying. However, both black aspergilli groups
were mostly isolated, at low and medium altitudes (<500 m). OTA contamination
was influenced by bunch position, although altitude did not significantly influenced
amounts. The fungal biodiversity was decreased during sun-drying of sultanas. The
widest diversity of species occurred at the sea level. However, A. niger aggregate,
were dominant during drying. Time of drying and altitude significantly influenced
fungal loads of black aspergilli. In contrast, OTA production (ca 0.001 - 0.0025 μg g
-
1
) was not significantly influenced by altitude and drying time. Shannon Index of
Biodiversity (H), for pre-harvest and pos-harvest studies, was determined for the first
time.
A. niger aggregate (ca 5.0 Log10 CFUs g
-1
) was predominant during industrial
processing, while A. carbonarius was only isolated at low levels (1.5-2.0 Log10 CFUs
g
-1
). Heat treatment (up to 90
o
C) appeared to be the key-procedure for the
elimination of fungal populations. In the contrary, SO2 treatment did not statistically
alter fungal population dynamics. OTA contamination was not significantly affected
by industrial processing.
In vitro studies conducted on both White Grape Juice Medium (WGJM) and in
sultanas with strains of A. carbonarius originated from Cretan sultanas and compared with a strain isolated from Italian wine grapes. They examined the impact of sodium
metabisulphite (NaMBS), elevated CO2 (up to 50%) concentrations and aw levels, on
black aspergilli spore germination, growth and OTA production. Moreover, fungal
interactions in vitro and in situ were also investigated.
In general, spore germination occurred over a wide range of sodium metabisulphite
concentrations, although germ tube extension was significantly controlled. At ≥ 750
mg L
-1
NaMBS, no spore germination was observed while both mycelial growth and
OTA production were completely inhibited. Medium concentrations of NaMBS (≤
250 mg L
-1
) enabled optimum spore germination, growth and OTA production (x
0.965 aw). The efficacy of controlled atmospheres x aw showed that there was very
little inhibitory effect on spore germination. However, both germ tube extension and
fungal growth were inhibited by 50% CO2. After 10 days, growth was not as
effectively controlled. Aw had a bigger effect on OTA production than modified
atmospheres. In situ experiments on sultanas confirmed these results. Competition
and dominance of A. carbonarius over other fungal species showed that aw and
temperature influenced Indices of Dominance and OTA production. In vitro and in
situ, OTA production by A. carbonarius was significantly influenced by the fungal
competitor used
Uma solução para atualização em OTA em aplicações embarcadas utilizando o ESP8266
No full textO crescimento exponencial da conectividade e o avanço dos sistemas tecnológicos aumentaram
significativamente a adoção de microcontroladores como o ESP8266 em uma ampla gama de
aplicações embarcadas em IoT. Nesse contexto, a manutenção de firmwares atualizados tornou-se
um requisito crítico para garantir o desempenho, a segurança e a confiabilidade dos dispositivos.
Métodos tradicionais de atualização, envolvendo conexões físicas, mostraram-se custosos, demorados
e suscetíveis a riscos operacionais. Como alternativa eficiente, o mecanismo de atualização
Over-the-Air (OTA) surgiu, permitindo atualizações de firmware de forma remota por meio de
conexões sem fio. Esta pesquisa explora as possibilidades, desafios e a implementação prática de
atualizações OTA utilizando especificamente o microcontrolador ESP8266.O objetivo principal
deste estudo foi desenvolver uma solução robusta, segura e eficiente de atualização OTA capaz de
realizar atualizações de firmware remotamente. A abordagem metodológica incluiu a definição
de requisitos funcionais e não funcionais claros, a implementação de uma arquitetura lógica de
aplicação baseada em APIs e filas de mensagens, e a avaliação do desempenho do sistema por
meio de experimentos práticos. A solução implementada utilizou dados de firmware no formato
JSON para integração perfeita e atualizações automatizadas, gerenciadas por meio do Arduino
CLI para compilação e RabbitMQ para o manuseio confiável de dados.Avaliações experimentais
demonstraram que a solução OTA proposta otimizou significativamente os processos de
gerenciamento de firmware, reduzindo os intervalos de atualização e os custos operacionais, ao
mesmo tempo em que manteve a confiabilidade do sistema por meio de mecanismos internos
de rollback. Além disso, a transmissão segura de dados foi garantida por meio da adoção de
protocolos criptográficos (SSL/TLS). Apesar dos ganhos evidentes em eficiência, as limitações
de memória do ESP8266 e a dependência da estabilidade da rede foram identificadas como
potenciais limitações, orientando direções para futuras pesquisas, como técnicas de compressão
de firmware, atualizações incrementais (delta) e estratégias aprimoradas de resiliência para
ambientes de rede instáveis
Ochratoxin A in Roasted Coffee from French Supermarkets and Transfer in Coffee Beverages: Comparison of Analysis Methods
No full textThe OTA content of 30 roasted coffees purchased in French supermarkets was evaluated by two validated different methods: one using immunoaffinity column (IAC) clean-up after alkaline extraction; the second using toluene extraction under acidic conditions. OTA recoveries (0.5 to 5 µg/kg) ranged from 16–49% with the alkaline extraction method and 55–60% with the acidic method. OTA recoveries from prepared beverages were similar with all methods (75–80%). All samples containing OTA ranged from trace (<LOQ) to 11.9 µg/kg. About 20 to 140% of OTA passed through the beverages. Recoveries of over 100% of OTA in beverages were due to three types of interferences: (i) formation of open-ring OTA (OP-OA) during alkaline extraction, (ii) isomerization of OTA during roasting, and (iii) presence of the nonchlorinated analogue OTB. The first two types of interference generate OTA derivatives that are not recognized by OTA antibodies, while OTB cross-reacts with OTA-antibodies. These analytical problems will seriously impact the amount of OTA detected, especially at the levels close to the limits from the EU legislation. Underestimation of OTA could be highly dangerous for health
Gnathia nubila Ota & Hirose, 2009, n. sp.
No full textGnathia nubila n. sp. (Figs. 1 –3, 6 A, B) Material examined. Holotype. 9.1 mm (NSMT-Cr 20878), from gill filaments and gill arches of spotted eagle ray Aetobatus narinari (Euphrasen, 1790) caught by commercial fishing (boat out of Hama Fishing Port), Nakagusuku Bay (26 °N, 127 °E), Okinawa Island, Ryukyu Archipelago, southwestern Japan. 30 November 2007, coll. Y. Ota. Paratypes. Two males and 4 females from the same fish host as the holotype (NSMT Cr 20879). One male and 19 larvae from gill filaments and gill arches of A. narinari caught by commercial fishing (Okinawa City Fishing Port), Nakagusuku Bay (26 °N, 127 °E), 13 September 2006, coll. Y. Ota (NSMT-Cr 20880). Description. Male (Figs. 1, 2). Body 9.0–10.0 mm (9.3 ± 0.5 mm, n = 4). Pigmentation of live specimens white; digestive organs black due to congealed host blood. Cephalosome (Fig. 1 A–C). Cephalosome covered with tubercles and setae, almost square with posterior margin convex, about one-fifth of total length. Posterior median tubercle prominent. Frontal border medially opened by 2 frontolateral processes with tubercles and several submarginal setae. Apex of mediofrontal process bifit and dentate (Fig. 1 D). Eyes well developed, about one-fourth length of cephalosome. Supraocular lobe low, not acute. Dorsal sulcus deep and narrow. Pereon (Fig. 1 A). All pereonite lengths about half of total length. Pereonite 1 short, not fused, reaching lateral margin of cephalosome. Pereonites 2–6, sparsely covered with setae and tubercles. Widths of pereonites 2, 3, and 4 similar. Pereonite 2 as long as pereonite 3 and slightly shorter than pereonite 4. Anterior constriction and anterolateral lobe present on pereonite 4. Pereonites 5 and 6 combined subequal in length to pereonites 2–4 combined. Areae laterales and lobi laterals present on pereonites 5 and 6, respectively. Pereonite 7 short and narrow, overlapping pleonite 1. Pleon (Fig. 1 A). Lateral margins of pleonites 1–5 fringed with long setae. Lengths of pleonites and pleotelson about one-quarter of total length. Epimera prominent on pleonites 3–5. Pleotelson (Fig. 1 D). Pleotelson narrow, covered with pectinate scales. Eight setae on lateral margin and 1 pair of setae on both dorsal surface and distal apex. Mandible (Fig. 1 E). Mandible length two-thirds of cephalosome length. Apex curved inward. One mandibular seta present near armed carina on mid-dorsal surface. Dentate blade occupies about two-fifths of mandible length. Basal neck and erisma prominent. Antennae. Antenna 1 (Fig. 1 F). Peduncle articles 2 and 3 covered with pectinate scales. Three, 4, and 1 feather-like bristles on distal margins of peduncles 1, 2, and 3, respectively. One seta on internal margins of peduncle 2, and several setae on external and distal margins of peduncle 3. Flagellar articles bearing an aesthetasc on both articles 3 and 4. One seta on distal margin of article 3. Article 5 with 1 feather-like bristle terminating in 3 setae and 1 aesthetasc. Antenna 2 (Fig. 1 G). Two feather-like bristles and several setae present on peduncle 4. A few setae present on distal margins of flagellar articles 1–6. Article 7 terminates in 5 setae. Maxilliped (Fig. 2 A). Endite reaches distal margin of palp article 1. Palp articles 1, 2, 3, and 4 bearing 6, 8, 5, and 9 plumose setae on external margins, respectively. Article 4 terminates in 4 simple setae. Pylopod (Fig. 2 B). Pylopod 3 articled. Several setae present on distal margins of articles 1 and 2. Article 1 large and elliptical, with 2 areolae, and 76 plumose setae on internal margin. A few setae and 1 feather-like bristle present near outer margin. Article 2 circular and fringed with fine setae. Article 3 minute. Pereopods (Fig. 2 C). Pereopod 2 bearing many setae; longer on outer margin than on inner. Pectinate scales on each article except basis; fine setae on inner margins of all articles. Basis oblong, bearing 2 featherlike bristles on outer margin. Ischium similar in length to basis, becoming larger distally. Merus about half length of ischium. Carpus rectangular and similar in length to merus. Propodus rectangular, about 1.2 times longer than carpus; bearing 2 spines on inner-mid and inner-distal margins. Dactylus with a few setae, terminating in unguis. Length of dactylus and unguis combined about half that of propodus. All pereopods similar in shape, size, and setation. Pleopods (Fig. 2 D). Pleopodal peduncle inner margin fringed with fine setae. One seta on outer distal corner, and a coupling hook on inner margin. Both pleopodal rami oval and equal in length. All pleopods subequal in shape. From 7 to 9 plumose setae and 1 simple seta (pl. 1, 2, 4) on exopods: pleopod 1; 7 plumose setae, pl. 2–4; 8, pl. 5; 9. From 4 to 8 pumose setae and 1 simple seta (pl. 2, 3) on endopods: pleopod 1; 6 plumose setae, pl. 2; 4, pl. 3–5; 8. Appendix masculina extending beyond half length of pleopod 2 endopod. Uropods (Fig. 1 D). Both rami subequal in length, extending beyond apex of pleotelson. Exopod bearing 19 setae and 7 plumose setae on external and internal margins, respectively. Endopod bearing 9 setae and 9 plumose setae on external and internal margins, respectively. Several feather-like bristles on dorsal surface. Penes (Fig. 2 E). Penes composed of 2 contiguous papillae and not prominent. Female (Fig. 3). Body 7.4 –8.0 mm (7.7 ± 0.3 mm, n = 4). Pigmentation of live specimens white. Cephalosome (Fig. 3 A–C). Cephalosome with several setae. Frontal margin slightly convex; pair of spots present. Pereon (Fig. 3 A, B). Pereonite 1 short, not fused, with central part protruding forward. Pereonites 3–6 oval, with 2 sutures, widths about two-thirds of lengths. Lateral shields of pereopods 4–6 visible dorsally. Pleon (Fig. 3 A, B). Several setae on pleonites 1–5 subequal in length. Pleotelson (Fig. 3 D). Two pairs of setae on lateral margin and apex. Antennae (Fig. 3 E, F). Setae on peduncle articles of both antennae fewer than in male. No pectinate scales on peduncle articles. Maxilliped (Fig. 3 G). Inner margin of basis and endite covered with pectinate scales. Endite reaches half length of palp article 1. Nine, 7, 9, 6, and 8 plumose setae on basis and articles 1, 2, 3, and 4, respectively. Oostegite elliptical. Pylopod (Fig. 3 H). Pylopod composed of 3 articles. Articles 1 and 2 covered with pectinate scales and fringed with fine setae on inner margins. Article 1 with suture bears 10 setae on lateral and distal margins. Article 2 rectangular, bearing 6 setae on distal margin. Article 3 minute. Pereopods (Fig. 3 I). Pereopods bear fewer setae than those of male; not covered with pectinate scales. Pereopods 5 and 6 larger than other pereopods. Pleopod (Fig. 3 J). One aesthetasc on outer margin of peduncle. Exopods and endopods oval, with 8 (exopods) or 6 (endopods) setae on distal margins, all vestigial. All pleopods subequal in shape. Uropod (Fig. 3 D). Uropodal rami slightly extended beyond apex of pleotelson. Exopod bears 19–21 setae on margin. Endopod bears 14–15 setae on margin. Immature praniza larva (Figs. 4, 7 A, B). Body 7.6–9.7 mm (8.4 ± 0.6 mm, n = 19). Dorsal thorax of live specimens black with white cloud-like pattern (Fig. 7 A); ventral thorax has distinct white line (Fig. 7 B). Distinct brown spot on eyes. Lateral margins of pleonites have brown pattern (see Fig. 7 A). Cephalosome (Fig. 4 A). Triangular, length same as width. Anterior margin of labrum straight. Eyes occupying half length of cephalosome. Pereon (Fig. 4 A, B). Pereonite 1 short. Pereonite 2 subequal in width to pereonite 3, with convex anterior margin. Pereonite 3 slightly longer than pereonite 2. Lateral shields of pereopods 4–6 visible in dorsal view, elliptical. Pleon (Fig. 4 A). Pleonites 1–4 subequal in length and slightly shorter than pleonite 5. Pleotelson (Fig. 4 C) with dentate lateral margin, bearing 3 pairs of setae on dorsal surface and apex. Antennae (Fig. 4 D, E). Internal margins of peduncles 2 and 3 of antenna 1 fringed with fine setae. Internal margins of peduncles 3 and 4 of antenna 2 fringed by fine setae. Mouth parts. Mandible (Fig. 4 F) with 9 teeth. Maxillule (Fig. 4 G) with 2 slender articles, fine setae on outer margin projecting to posterior, 7 teeth on apex. Paragnath (Fig. 4 H) slightly curved. Maxilliped (Fig. 4 I) composed of basis and 2 -articled palp. Basis with 1 coupling hook on inner margin and endite with 1 seta. Apex of palp 1 slightly dentate. Apex of palp 2 divided into 2 parts; 1 seta and 1 tooth on inner apex, 5 setae and 1 spine on outer part. Gnathopod (Fig. 4 J) pereopodal in shape with reduced carpus. One projection on distal margin of merus. Propodus with distal bulbous protrusion. Dactylus terminating in sharp, pointed unguis. Pereopods. Pereopod 2 (Fig. 4 K) more slender than that of male. Inner margins of carpus and propodus covered with pectinate scales. Pleopods (Fig. 4 L). Exopod fan-shaped with 7–9 plumose setae on distal margins. Endopod rectangular and as large as exopod; 7 or 8 plumose setae on distal margins. All pleopods subequal in shape. Uropod (Fig. 4 C) just reaches apex of pleotelson. Exopod bears 6 setae and 4 plumose setae on margin. Endopod bears 2 setae and 7 plumose setae on margin. Etymology. The specific name nubila is derived from the Latin meaning “cloudy”, referring to the larval thorax pattern. Remarks. Among Gnathia species described so far worldwide, the body length, and shape of the cephalosome and pleotelson of male G. nubila is most similar to those of G. grandilaris. However, the mediofrontal process of G. grandilaris is triangular-shaped lobe and conical (Coetzee et al. 2008) (G. grandilaris has the bifit one). Because G. trimaculata and G. m a c u l o s a have been found from this area (Ota & Hirose, 2009), these species may be found with G. nubila, but they are distinguished from G. nubila by the following features. Gnathia trimaculata has a mediofrontal process on the frontal border and a more slender pylopod (Coetzee et al. 2009). Gnathia maculosa is smaller (3.9–5.8 mm) and lacks a mediofrontal process (Ota & Hirose, 2009). Frontal borders of G. n o t o s t i g m a Cohen & Poore, 1994 and G. c o o k i Müller, 1989 are also similar in shape to that of G. nubila. However, G. notostigma has very pronounced paraocular tubercles and wider pleotelson (Cohen & Poore, 1994). Gnathia cooki has long and basally broadened penes and a wider pleotelson (Müller, 1989). Because species descriptions of gnathiids have traditionally been based on the morphology of adult males, detailed descriptions of larvae and female adults are lacking in many literatures. Females of the genus Gnathia have been described in detail for the following species: G. firingae, G. c a m u r i p e n i s, G. limicola, G. m a c u l o s a, G. a f r i c a n a, G. pantherina, G. p i l o s u s, G. gurjanovae, and G. trimaculata (Müller, 1991; Smit & Basson, 2002; Smit et al. 2002; Tanaka, 2004; Golovan, 2006; Ota et al. 2007; Coetzee et al. 2008; Ota & Hirose, 2009). Gnathia maculosa most closely resembles G. nubila. However, the frontal border of G. nubila has a pair of spots, the pleopodal rami are oval, and the body is larger (7.4 –8.0 mm). The pleopodal rami of G. m a c u l o s a are fan-shaped, and the body length is smaller (4.4–5.5 mm) than that of G. nubila (Ota & Hirose, 2009). Detail descriptions of praniza larvae were limited worldwide; G. firingae, G. africana, G. pantherina, G. camuripenis, G. limicola, G. capillata, G. grandilaris, G. trimaculata, and G. m a c u l o s a (Müller, 1991; Smit et al., 1999; Smit & Basson, 2002; Tanaka, 2004; Nunomura & Honma, 2004; Ota et al., 2007; Coetzee et al., 2008, 2009; Ota & Hirose, 2009). Among the gnathiid larvae described so far, G. nubila is most similar to G. grandilaris. However, G. grandilaris lacks a distinct brown spot on the eyes and a distinct white line on the ventral thorax, and it has a shorter pleotelson (Coetzee et al. 2008). Gnathia capillata, G. trimaculata, and G. maculosa larvae have all been found as ectoparasites on elasmobranchs from Japan; these 3 species are distinguishable from G. nubila as follows. Gnathia capillata has a wider pleotelson, and its pereonite 4 is distinctively separated from pereonites 5 and 6 (Nunomura & Honma, 2004). Gnathia trimaculata has yellow-greenish color with black spots on the thorax and its shorter pleotelson (Coetzee et al. 2009). Gnathia maculosa has wider pleotelson, shorter body length in the immature stage (4.2–5.8 mm), and white speckled or dappled pattern on the thorax (Ota & Hirose, 2009). Praniza larvae of G. c a m u r i p e n i s and G. limicola have also been described from the Ryukyus. Gnathia nubila is easy to distinguish from these 2 species by the following criteria: the body lengths of immature G. camuripenis and G. limicola are 3 mm, and the pleotelson is wider and not elongated (Tanaka, 2004; Ota et al. 2007).Published as part of Ota, Yuzo & Hirose, Euichi, 2009, Gnathia nubila n. sp. and a new record of Gnathia grandilaris (Crustacea, Isopoda, Gnathiidae) that parasitizes elasmobranchs from Okinawan coastal waters, Japan, pp. 43-55 in Zootaxa 2238 on pages 44-51, DOI: 10.5281/zenodo.19046
Ochratoxin A: In Utero Exposure in Mice Induces Adducts in Testicular DNA
No full textOchratoxin A (OTA) is a nephrotoxin and carcinogen that is associated with Balkan endemic nephropathy and urinary tract tumors. OTA crosses the placenta and causes adducts in the liver and kidney DNA of newborns. Because the testis and kidney develop from the same embryonic tissue, we reasoned that OTA also may cause adducts transplacentally in the testis. We tested the hypothesis that acute exposure to OTA, via food and via exposure in utero, causes adducts in testicular DNA and that these lesions are identical to those that can be produced in the kidney and testis by the consumption of OTA. Adult mice received a single dose of OTA (from 0–1,056 µg/kg) by gavage. Pregnant mice received a single i.p. injection of OTA (2.5 mg/kg) at gestation day 17. DNA adducts were determined by 32P-postlabeling. Gavage-fed animals sacrificed after 48 hours accumulated OTA in kidney and testis and showed DNA adducts in kidney and testis. Some OTA metabolites isolated from the tissues were similar in both organs (kidney and testis). The litters of mice exposed prenatally to OTA showed no signs of overt toxicity. However, newborn and 1-month old males had DNA adducts in kidney and testis that were chromatographically similar to DNA adducts observed in the kidney and testis of gavage-fed adults. One adduct was identified previously as C8-dG-OTA adduct by LC MS/MS. No adducts were observed in males from dams not exposed to OTA. Our findings that in utero exposure to OTA causes adducts in the testicular DNA of male offspring support a possible role for OTA in testicular cancer
Innovative Ochratoxin A (OTA) extraction platforms using OTA-binding proteins
No full textDissertação de mestrado em BiotechnologyWine is a widely consumed product that is often associated with contaminations of toxic metabolites called mycotoxins. The most important mycotoxin associated to wine is ochratoxin A (OTA), and its detection usually involves the clean-up of samples with immunoaffinity columns (IAC) and quantification by HPLC coupled with fluorescence detection (FL). However, the several drawbacks associated with the use of the IAC led to the search for alternative clean-up methods. Thus, in this work, new platforms for OTA clean-up from wine were developed, based on proteins whose affinity towards OTA makes them suitable candidates to mimic the binding properties of the antibodies used in the IAC method.
In a first approach, a protein with high affinity towards OTA, was used to develop a new solid phase extraction (SPE) method for the extraction of the mycotoxin from wine and subsequent quantification by HPLC-FL. The capture of OTA by the columns constructed with agarose-immobilized OTA binding protein was optimized to allow the full recovery of OTA in wine, and the method was further validated by the evaluation of various parameters such as recovery rates, selectivity and limits of detection (LOD) and quantification (LOQ). The developed method was selective enough for a reliable determination of OTA in wine, presenting recovery rates superior to 98% and LOD and LOQ of 0.02 and 0.05 μg L-1, respectively. Furthermore, the performance of the developed method revealed no significant differences in relation to the IAC method in concentrations up to 2 μg L-1 of OTA. In comparison with other conventional SPE methods reported in the literature, the developed method has proved to be suitable to be employed in the determination of OTA in wine.
In a second approach, the domain where lies the primary binding site of OTA in the OTA-binding protein used in the first approach was evaluated as OTA ligand for developing OTA extraction platforms based on this domain. For that, the domain was recombinantly produced, fused to a 6xHis tag, with and without the thioredoxin (TrxA) solubility partner, in two E. coli strains, BL21 (DE3) and Origami 2 (DE3). Soluble proteins, with and without TrxA, were produced by both strains, but the Origami strain provided higher yields of production (18.7 and 23.4 mg per litre of culture, respectively). In addition, differences observed in the affinity of the proteins for the nickel resin in the purification suggested that the structures acquired by the recombinant proteins produced in each strain were different. Furthermore, the fact that fusion proteins were less prone to degradation suggested that TrxA contributed for their stability. Studies of fluorescence spectroscopy revealed that only the recombinant proteins produced by the Origami strain were capable of interacting with OTA, thus indicating that these proteins were functional. The ability of the proteins produced from this strain, with and without TrxA, immobilized in nickel via the 6xHis tag, to capture the mycotoxin in buffer solutions was evaluated. SPE columns constructed with the nickel-immobilized recombinant proteins did not show the ability to effectively capture OTA. On the other hand, incubation assays performed in eppendorfs allowed decreasing OTA in solution up to 54 and 63%, respectively for immobilized proteins, with and without TrxA. These results open perspectives for the development of OTA extraction platforms based on the recombinant domain of this OTA-binding protein with matrixes less expensive than the agarose used in the first approach by means of specific purification tags.O vinho é um produto largamente consumido que está frequentemente associado a contaminações com metabolitos tóxicos denominados de micotoxinas. A micotoxina mais importante associada ao vinho é a ocratoxina A (OTA), e a sua deteção envolve normalmente um passo de concentração das amostras com colunas de imunoafinidade (IAC) e deteção por HPLC acoplada com deteção por fluorescência (FL). Contudo, as diversas desvantagens associadas ao uso das IAC levaram à procura de métodos de concentração alternativos. Assim, neste trabalho, foram desenvolvidas novas plataformas de concentração de OTA do vinho, baseadas no uso de proteínas cuja afinidade para a OTA as torna candidatos adequados para mimetizar as propriedades de ligação dos anticorpos usados no método IAC.
Numa primeira abordagem, uma proteína com alta afinidade para a OTA foi usada para desenvolver um novo método de extração em fase solida (SPE) para extrair esta micotoxina do vinho e subsequente quantificação por HPLC-FL. A captura de OTA por colunas construídas com a proteína em estudo imobilizada em agarose foi otimizada de forma a permitir uma recuperação total da micotoxina presente no vinho, e o método foi posteriormente validado através da avaliação de parâmetros como taxas de recuperação, seletividade e limites de deteção (LOD) e quantificação (LOQ). O método desenvolvido foi suficientemente seletivo para permitir uma quantificação confiável de OTA no vinho, apresentando taxas de recuperação superiores a 98% e um LOD e LOQ de 0.02 e 0.05 μg L-1, respetivamente. Em adição, o desempenho do método desenvolvido não apresentou diferenças significativas em relação ao método das IAC em concentrações até 2 μg L-1 de OTA. Em comparação com outros métodos convencionais de SPE reportados na literatura, o método desenvolvido revelou ser adequado para aplicação na determinação de OTA no vinho.
Numa segunda abordagem, o domínio da proteína usada na primeira abordagem que contém o principal local de ligação da micotoxina, foi avaliado como ligando da OTA para o desenvolvimento de plataformas de extração de OTA baseadas nesse domínio. Para isso, este foi produzido de forma recombinante, em fusão com um 6xHis tag, com e sem tiorredoxina (TrxA) como parceiro de solubilidade, em duas estirpes de E. coli, BL21 (DE3) e Origami 2 (DE3). O domínio proteico solúvel, com e sem TrxA, foi produzido por ambas as estirpes, mas a estirpe Origami obteve maiores rendimentos de produção (18.7 e 23.4 mg por litro de cultura, respetivamente). Em adição, as diferenças observadas na afinidade das proteínas para a resina de níquel na purificação sugeriram que as estruturas adquiridas pelas proteínas produzidas em cada estirpe eram diferentes. Além disso, o facto de que que as proteínas de fusão se mostraram menos suscetíveis a degradação sugere que a TrxA contribuiu para a sua estabilidade. Estudos de espectroscopia de fluorescência revelaram que apenas as proteínas recombinantes produzidas pela estirpe Origami foram capazes de interagir com a OTA, indicando assim que estas se encontravam funcionais. A capacidade das proteínas produzidas por esta estirpe, com e sem TrxA, imobilizadas em níquel a partir do 6xHis tag, para capturarem a micotoxina em soluções tampão foi avaliada. Colunas SPE construídas com estas proteínas recombinantes imobilizadas em níquel não mostraram a capacidade de capturar efetivamente a OTA. Por outro lado, os ensaios realizados em “eppendorfs” permitiram reduções de OTA em solução até 54 e 63%, respetivamente para as proteínas imobilizadas com e sem TrxA. Estes resultados abrem perspetivas para o desenvolvimento de plataformas de extração de OTA baseadas neste domínio da proteína estudada com matrizes menos caras que a agarose usada na primeira abordagem por meio de tags de purificação específicos
A 10 fJ·K <sup>2</sup>Wheatstone Bridge Temperature Sensor with a Tail-Resistor-Linearized OTA
No full textThis article describes a highly energy-efficient Wheatstone bridge temperature sensor. To maximize sensitivity, the bridge is made from resistors with positive (silicided diffusion) and negative (poly) temperature coefficients. The bridge is balanced by a resistive (poly) FIR-DAC, which is part of a 2nd-order continuous-time delta-sigma modulator (CT Δ Σ M). Each stage of the modulator is based on an energy-efficient current-reuse OTA. To efficiently suppress quantization noise foldback, the 1st stage OTA employs a tail-resistor linearization scheme. Sensor accuracy is enhanced by realizing the poly arms of the bridge and the DAC from identical unit elements. Fabricated in a 180-nm CMOS technology, the sensor draws 55 μ W from a 1.8-V supply and achieves a resolution of 150 μ K rms in an 8-ms conversion time. This translates into a state-of-the-art resolution figure-of-merit (FoM) of 10 fJ · K2. Furthermore, the sensor achieves an inaccuracy of ±0.4 °C (3 σ) from -55 °C to 125 °C after a ratio-based one-point trim and systematic non-linearity removal, which improves to ±0.1 °C (3 σ) after a 1st-order fit.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Hemigrammus durbinae Ota 2015
No full text<i>Hemigrammus durbinae</i> Ota, Lima & Pavanelli, 2015: 221, fig. 1. <p> <b>Paratypes:</b> 6 lots, 259 specimens —NUP 6265, 10, 19.1–21.7 mm SL; NUP 9547, 1 c&s: Brazil, Mato Grosso, Chapada dos Guimarães boundary with Nobres, córrego Forquilha, tributary of rio Cuiabá, rio Paraguai basin, 14°41’00”S, 55°32’00”W, Nupélia staff, 24 Apr 2000. NUP 2153, 157, 21.5–25.4 mm SL: Brazil, Mato Grosso, Barão de Melgaço, baía de Chacororé, tributary of rio Cuiabá, rio Paraguai basin, 14°57’07”S, 55°42’59”W, Nupélia staff, 24 Feb 2003. NUP 6260, 19, 19.1–21.3 mm SL: Brazil, Mato Grosso, Barão de Melgaço, baía Sinhá Mariana, tributary of rio Cuiabá, 16°20’20”S, 55°54’10”W, Nupélia staff, 26 Apr 2003. NUP 9543, 22 c&s, 21.6–24.1 mm SL: same locality and collectors as previous, 24 Feb 2003. NUP 6261, 50, 19.4–22.5 mm SL: same locality and collectors as previous, 20 Mar 2002.</p> <p> <b>Remarks:</b> The number of specimens from the lot NUP 2153 was incorrectly cited as 158 in the original description.</p>Published as part of <i>De Oliveira, Rianne C., Ota, Renata R., Deprá, Gabriel C., Zawadzki, Cláudio H., Pavanelli, Carla S. & Da Graça, Weferson J., 2022, Catalog of type specimens of the fish collection of the Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (NUP), Universidade Estadual de Maringá Paraná, Brazil, pp. 1-43 in Zootaxa 5128 (1)</i> on page 7, DOI: 10.11646/zootaxa.5128.1.1, <a href="http://zenodo.org/record/6479497">http://zenodo.org/record/6479497</a>
Indigenous earth building construction technology in Ota, Nigeria
No full text206-212This paper documents the earth construction
techniques used in Ota in order to preserve the earth construction heritage of
the Ota people while checking the suitability of the earth materials used,
using soil classification tests. Interviews of earth constructors in six
villages in Ota were conducted to determine their material selection criteria,
material processing and construction techniques. Colour and texture of soil
samples were determined and in-situ tests such as biscuit, cigar,
hand-wash and adhesion tests were performed on soil samples used for earth
building construction at three of the villages. Natural moisture content, sieve
and hydrometer analyses, and Atterberg limits test were performed in the
laboratory, on soil samples taken from these three locations. It was revealed
from the interview sessions that cob construction technique is widely used and
that earth building construction is becoming less-appealing to the youths in
these locations. The soil samples at the three locations were classified as
clayey sand and were ascertained to be suitable for earth building
construction. Earth constructors in Ota perceive that earth buildings are more
economical and energy-conserving. Earth buildings are a potential solution to
the global housing crisis experienced, especially in developing countries
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