RESUMEN

Os aminoácidos tipo micosporinas (MAAs) são compostos, produzidos por algumas espécies de cianobactérias e outros microorganismos, principalmente quando são expostos a radiação ultravioleta (UVR). Estes compostos, que vêm demonstrando funções fotoprotetoras e antioxidantes, têm sido pesquisados para aplicação em protetores solares e em produtos antienvelhecimento. O presente estudo focou na caracterização de cianobactérias e outros organismos quanto à produção de MAAs com potencial aplicação em cosméticos. Neste estudo foram desenvolvidos diversos métodos para identificação (via HPLC-DAD-MS/HRMS), purificação (via HPLC-DAD) e quantificação de MAAs (via LC-MS/MS). Pelo método de identificação de MAAs verificou-se que, das 75 cianobactérias estudadas, 27 cepas (38%) sintetizam MAAs. A cepa Oscilatoria sp. CMMA 1600 produziu a maior diversidade de MAAs. 10 MAAs diferentes foram identificados incluindo um MAA de massa molecular 316 Da. Através de dados espectroscópicos obtidos via HPLC-DAD-HRMS e RMN 1D e 2D confirmou-se que se tratava da micosporina-glicina-alanina. A biossíntese natural deste composto por cianobactérias foi relatada pela primeira vez neste estudo. Quanto à quantificação de MAAs, o protocolo de extração otimizado possibilitou uma excelente recuperação dos compostos de interesse, além de ser bastante simples e não utilizar solventes poluentes. As análises via LC-MS/MS foram realizadas através de experimentos de MRM em modo positivo usando uma coluna de fase reversa. O método validado permitiu determinar e quantificar com precisão os MAAs porphyra-334, shinorina e micosporina-glicina-alanina em corridas de apenas 6 minutos, com limites de deteção inferiores a 0,005 µg.mg -1. Aplicando o método de LC-MS/MS realizaram experimentos de indução de MAAs através de exposição à UVR tendo-se observado um aumento da concentração de MAAs nas cepas que já sintetizam estes compostos e, outras cepas começaram a produzir pelo menos um MAA. As cepas de S. torques-reginae (ITEP-024 e ITEP-026) produziram a maior concentração de MAAs. A cepa ITEP-024 foi ainda exposta a diferentes radiações tendo-se observado que a UVB é que mais influencia a produção de MAAs. Neste estudo foi demonstrado o potencial das cianobactérias como produtores de MAAs que podem ser utilizados como fotoprotores em protetores solares

Mycosporines and mycosporine-like amino acids (MAAs) are UV-absorbing compounds produced by cyanobacteria and other organisms, especially upon exposer to solar ultraviolet radiation (UVR). These compounds are photoprotective and some have additional antioxidant functíons useful to the natural cosmetics market. This study aims to identify MAAs-producing cyanobacteria with potential applicatíons in cosmetics. A HPLC-DAD-MS/HRMS method for the identification of MAAs was developed. Out of the 75 cyanobacteria studied, 27 strains (38%) synthesized MAAs. Oscilatoria sp. CMMA 1600, from homocyte type, produced the greatest diversity of MAAs. 10 different MAAs were identified including a MAA with molecular weight of 316 Da. The chemical structure of mycosporine-glycine-alanine was confirmed by 1D/2D NMR and HRMS analyses. This compound has never been reported from a natural source. In this study, a validated LC-MS/MS quantification method for MAAs is also presented. An easy-to-handle and rapid extraction procedure was developed which uses only water and volatile additives as the extractor solvents. The LC-MS/MS method was performed using multiple reaction monitoring in positive mode with a reverse-phase column. The method enabled the accurate determination and quantification of the MAAs porphyra-334, shinorine and mycosporine-glycine-alanine in a 6 minutes running time, with limits of detection < 0.005 µg.mg-1. MAAs induction experiments were performed through UVR exposure. MAAs are constitutively produced by some cyanobacteria and production was further enhanced following UVirradiance. Other strains start to produce at least one MAA after UV-irradiance. Sphaerospermopsis torques-reginae strain (ITEP-024 and ITEP-026) produced the highest concentration of these photoprotective compounds. S. torques-reginae ITEP 024 strain was further exposed to different radiation compositíons. MAAs were significantly influenced by UVB. In this study, the potential of cyanobacteria as MAA producers, that can be used as photoprotectors in sunscreens, has been demonstrated

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RESUMEN

O objetivo do experimento foi avaliar o grau de sincronização do cio e a taxa de prenhez de vacas de corte tratadas com acetato de melengestrol (MGA) e cipionato de estradiol (ECP). Quarenta vacas lactantes Caracu (uma raça taurina local) mantidas em pastagens de Panicum maximum cv. Tanzania e suplementadas com silagem de milho, receberam o equivalente a 0,5 mg/animal/dia de MGA durante 14 dias. No dia 5, os animais foram divididos aleatoriamente em dois grupos. O grupo 1 (n=21) recebeu uma injeção i.m. de 2,0 mg de ECP enquanto que o grupo 2 (n=19) recebeu 1 ml de solução salina. O cio (detecção visual) foi registrado em todos os animais no período de 120 horas após a retirada do MGA, mas somente os animais do grupo 1 foram inseminados. Os animais do grupo 2 receberam 150 μg do análogo de PGF2α, cloprostenol 17 dias após a retirada do MGA e inseminados no cio induzido. Em ambos grupos, as vacas não detectadas no cio durante o dia foram colocadas com um touro durante a noite para uma eventual cobertura. O diagnóstico de prenhez foi realizado, por ultrassonografia, 40 dias após a IA. Os dados foram analisados pelo teste de Qui-quadrado. Oito (38,1%) animais do grupo 1 e 7 (36,8%) do grupo 2 apresentaram cio após a retirada do MGA (P>0,05). A taxa de concepção dos animais inseminados foi de 37,5% e 50,0% para os grupos 1 e 2, respectivamente (P>0,05). Esse índice aumentou para 58,3% (grupo 1) e 64,3% (grupo 2) quando foram consideradas as vacas cobertas pelo touro durante a noite. Esses resultados sugerem que é possível aproveitar o primeiro cio de fêmeas tratadas com ECP no dia 5 de um tratamento com MGA durante 14 dias. Adicionalmente, considerando o elevado número de animais cobertos pelo touro durante a noite, recomenda-se o uso de ferramentas auxiliares para identificar os animais que apresentam cio noturno ou, ainda, utilizar a monta natural em associação com a IA.

The objective of this experiment was to evaluate estrous synchronization responses and pregnancy rates of beef cows treated with melengestrol acetate (MGA) and estradiol cypionate (ECP). Forty lactating Caracu cows (a locally adapted Bostaurus taurus breed) grazing on Panicum maximum cv. Tanzania and supplemented with corn silage received the equivalent of 0.5 mg/animal/day of MGA for 14 days. On day 5, the animals were randomly assigned to one of two groups: group 1 (n=21) received an im injection of 2.0 mg ECP and group 2 (n=19) received 2 ml saline. Animals of group 1 that exhibited estrus within 120 hours after withdrawal of MGA were inseminated (AI), while animals of group 2 were treated with cloprostenol 17 days after MGA removal and were inseminated during induced estrus. In both groups, cows without estrus detection during the day stayed with a bull at night for possible mating. Pregnancy was diagnosed by ultrasound examination 40 days after AI. Chi-square analyses were used to detect differences between groups. Eight (38.1%) animals of group 1 and 7 (36.8%) of group 2 showed estrus after withdrawal of MGA (P>0.05). The conception rates in groups 1 and 2 were, respectively, 37.5% and 50.0% for inseminated cows and 58.3% and 64.3% for for inseminated cows in addition to mated by the bull at night (P>0.05). These results suggest that it is possible to use the first estrus of females treated with ECP on day 5 of a 14-day MGA treatment. Furthermore, considering the large number of cows mated by the bull at night, it is recommended to use estrus detection tools as an aid for the identification of such animals or to combine AI and bulls for breeding.

Asunto(s)

RESUMEN

O objetivo do experimento foi avaliar o grau de sincronização do cio e a taxa de prenhez de vacas de corte tratadas com acetato de melengestrol (MGA) e cipionato de estradiol (ECP). Quarenta vacas lactantes Caracu (uma raça taurina local) mantidas em pastagens de Panicum maximum cv. Tanzania e suplementadas com silagem de milho, receberam o equivalente a 0,5 mg/animal/dia de MGA durante 14 dias. No dia 5, os animais foram divididos aleatoriamente em dois grupos. O grupo 1 (n=21) recebeu uma injeção i.m. de 2,0 mg de ECP enquanto que o grupo 2 (n=19) recebeu 1 ml de solução salina. O cio (detecção visual) foi registrado em todos os animais no período de 120 horas após a retirada do MGA, mas somente os animais do grupo 1 foram inseminados. Os animais do grupo 2 receberam 150 μg do análogo de PGF2α, cloprostenol 17 dias após a retirada do MGA e inseminados no cio induzido. Em ambos grupos, as vacas não detectadas no cio durante o dia foram colocadas com um touro durante a noite para uma eventual cobertura. O diagnóstico de prenhez foi realizado, por ultrassonografia, 40 dias após a IA. Os dados foram analisados pelo teste de Qui-quadrado. Oito (38,1%) animais do grupo 1 e 7 (36,8%) do grupo 2 apresentaram cio após a retirada do MGA (P>0,05). A taxa de concepção dos animais inseminados foi de 37,5% e 50,0% para os grupos 1 e 2, respectivamente (P>0,05). Esse índice aumentou para 58,3% (grupo 1) e 64,3% (grupo 2) quando foram consideradas as vacas cobertas pelo touro durante a noite. Esses resultados sugerem que é possível aproveitar o primeiro cio de fêmeas tratadas com ECP no dia 5 de um tratamento com MGA durante 14 dias. Adicionalmente, considerando o elevado número de animais cobertos pelo touro durante a noite, recomenda-se o uso de ferramentas auxiliares para identificar os animais que apresentam cio noturno ou, ainda, utilizar a monta natural em associação com a IA.(AU)

The objective of this experiment was to evaluate estrous synchronization responses and pregnancy rates of beef cows treated with melengestrol acetate (MGA) and estradiol cypionate (ECP). Forty lactating Caracu cows (a locally adapted Bostaurus taurus breed) grazing on Panicum maximum cv. Tanzania and supplemented with corn silage received the equivalent of 0.5 mg/animal/day of MGA for 14 days. On day 5, the animals were randomly assigned to one of two groups: group 1 (n=21) received an im injection of 2.0 mg ECP and group 2 (n=19) received 2 ml saline. Animals of group 1 that exhibited estrus within 120 hours after withdrawal of MGA were inseminated (AI), while animals of group 2 were treated with cloprostenol 17 days after MGA removal and were inseminated during induced estrus. In both groups, cows without estrus detection during the day stayed with a bull at night for possible mating. Pregnancy was diagnosed by ultrasound examination 40 days after AI. Chi-square analyses were used to detect differences between groups. Eight (38.1%) animals of group 1 and 7 (36.8%) of group 2 showed estrus after withdrawal of MGA (P>0.05). The conception rates in groups 1 and 2 were, respectively, 37.5% and 50.0% for inseminated cows and 58.3% and 64.3% for for inseminated cows in addition to mated by the bull at night (P>0.05). These results suggest that it is possible to use the first estrus of females treated with ECP on day 5 of a 14-day MGA treatment. Furthermore, considering the large number of cows mated by the bull at night, it is recommended to use estrus detection tools as an aid for the identification of such animals or to combine AI and bulls for breeding.(AU)

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RESUMEN

Short-term feeding of melengesterol acetate (MGA) was used in two trials to improve synchrony of ovulation, increase pregnancy rates to first service TAI (experiment 1), and shorten the interval from PGF2α injection to estrus in beef cows (experiment 2). In experiment 1 a total of 192 beef cows were assigned to either the Co-Synch (n = 95) or the MGA: 7-11Synch + TAI (n = 97) protocols. MGA: 7-11Synch + TAI cows were fed MGA (0.5 mg/h/day) for 7 days and administered PGF2α on the last day of MGA feeding. On day -7, four days later, cows in both groups (Co-Synch and MGA: 7-11Synch + TAI) were administered GnRH followed with PGF2α on day 0, then GnRH was administered 48 h later and concurrently inseminated. Overall pregnancy rate was 97/192 (51%). Number of cows with functional CL at day 0 was greater (P > 0.001) in the MGA: 7-11Synch + TAI group (94/97) than the Co-Synch group (76/95) suggesting that the MGA: 7-11Synch + TAI protocol successfully induced ovulations and formation of functional CL or luteinized follicles capable of responding to PGF2α. In experiment 2 purebred Angus cows (n = 109) and purebred Simmental cows (n = 63) were included in Select Synch (n = 84) or MGA: 7-11Synch (n = 88) protocols. Cows in the MGA: 7-11Synch group were fed MGA (0.5 mg/h/day) for 7 days and PGF2α was administered on the last day of MGA feeding (day -11). On day -7, four days later, all cows (Select Synch and MGA: 7-11Synch) were administered GnRH followed with PGF2α on day 0. Within -24 to 96 h of PGF2α administration, 128/171 (75%) cows exhibited estrus and were inseminated. First service conception and pregnancy rates during the first synchronization period (day -1 to day 4) were not different (P > 0.10) between the two groups. Overall conception and pregnancy rates were 99/128 (77%) and 99/171 (58%), respectively. Cows in the Select Synch group had a shorter (P < 0.05) interval to estrus (54.5 ± 22.2 h) than cows in the MGA: 7-11Synch protocol (61.2 ± 14.9 h). The MGA: 7-11Synch protocol resulted in a higher degree of estrus synchrony (49/56, 88%) in a 24 h peak response period (48 to 72 h) after PGF2α injection compared to Select Synch cows (46/67, 69%). Tighter synchrony of estrus suggests that MGA: 7-11Synch offers the potential for fixed-time AI programs.

Asunto(s)

RESUMEN

Short-term feeding of melengesterol acetate (MGA) was used in two trials to improve synchrony of ovulation, increase pregnancy rates to first service TAI (experiment 1), and shorten the interval from PGF2α injection to estrus in beef cows (experiment 2). In experiment 1 a total of 192 beef cows were assigned to either the Co-Synch (n = 95) or the MGA: 7-11Synch + TAI (n = 97) protocols. MGA: 7-11Synch + TAI cows were fed MGA (0.5 mg/h/day) for 7 days and administered PGF2α on the last day of MGA feeding. On day -7, four days later, cows in both groups (Co-Synch and MGA: 7-11Synch + TAI) were administered GnRH followed with PGF2α on day 0, then GnRH was administered 48 h later and concurrently inseminated. Overall pregnancy rate was 97/192 (51%). Number of cows with functional CL at day 0 was greater (P > 0.001) in the MGA: 7-11Synch + TAI group (94/97) than the Co-Synch group (76/95) suggesting that the MGA: 7-11Synch + TAI protocol successfully induced ovulations and formation of functional CL or luteinized follicles capable of responding to PGF2α. In experiment 2 purebred Angus cows (n = 109) and purebred Simmental cows (n = 63) were included in Select Synch (n = 84) or MGA: 7-11Synch (n = 88) protocols. Cows in the MGA: 7-11Synch group were fed MGA (0.5 mg/h/day) for 7 days and PGF2α was administered on the last day of MGA feeding (day -11). On day -7, four days later, all cows (Select Synch and MGA: 7-11Synch) were administered GnRH followed with PGF2α on day 0. Within -24 to 96 h of PGF2α administration, 128/171 (75%) cows exhibited estrus and were inseminated. First service conception and pregnancy rates during the first synchronization period (day -1 to day 4) were not different (P > 0.10) between the two groups. Overall conception and pregnancy rates were 99/128 (77%) and 99/171 (58%), respectively. Cows in the Select Synch group had a shorter (P < 0.05) interval to estrus (54.5 ± 22.2 h) than cows in the MGA: 7-11Synch protocol (61.2 ± 14.9 h). The MGA: 7-11Synch protocol resulted in a higher degree of estrus synchrony (49/56, 88%) in a 24 h peak response period (48 to 72 h) after PGF2α injection compared to Select Synch cows (46/67, 69%). Tighter synchrony of estrus suggests that MGA: 7-11Synch offers the potential for fixed-time AI programs.(AU)

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