CRIOPRESERVAÇÃO DE CALOS DE ARROZ

Cryopreservation is a technique that allows maintaining long-term germoplasma using ultra-reduced temperature. The objective of this study was to evaluate the regeneration seed´s callus of rice cryopreservated. Seeds of rice BRS-7 TAIM, were peeled and desinfested for establishment in vitro, distributed in flasks containing MS (Murashige & Skoog, 1962) 2,5 mg dm-3 of 2,4 D for induction of callus and maintained the temperature of ±25 ºC in the darkness. After twelve days the calluses were cryopreservated in liquid nitrogen for one hour, thawed 37º C and put back in the middle of cultivation for proliferation. It was used fifty callus by treatment: Test, Test cryopreservated, Glycerol 500 g dm-3 and Glycerol 500 g dm-3 cryopreservated. The evaluation of the proliferation was accomplished to the thirty days being observed the size and coloration of the callus. The material was transferred for middle of regeneration MS 10 mg dm–3 sucrose, 0,5 mg dm-3 of ANA and 2,0 mg dm-3 of BAP and it was incubated in fotoperíodo of 16 h. The evaluation of the regeneration was accomplished to the thirty and forty five days of incubation, the parameters were: growth of the callus, sprout and callus number, number of callus with sprout and sprout/callus number. In the proliferation the callus of the treatment Test cryopreservated rusted, however it was observed in the regeneration, to the thirty days, that the same ones presented such adult and number of sprout, and to the forty five days adult number of sprouts than the other treatments. It is ended that the cryopreservation technique can be used in callus of seeds of rice, not affecting the regenerative capacity.A criopreservação é uma técnica que mantém germoplasma por longo prazo. Objetivou-se verificar o efeito da criopreservação em nitrogênio líquido na regeneração de calos de arroz induzidos a partir de sementes maduras e avaliar o uso do glicerol como agente crioprotetor. Sementes de arroz BRS-7 TAIM, foram descascadas e desinfestadas, distribuídas em frascos contendo meio MS 2,5 mg dm–3 de 2,4 D para indução de calos e mantidos a temperatura de ±25 ºC no escuro. Após doze dias os calos foram criopreservados em nitrogênio líquido por uma hora, descongelados a 37º C e inoculados no meio de cultivo para proliferação. Utilizou-se cinqüenta calos por tratamento: Testemunha, Testemunha criopreservada, Glicerol 500 g dm-3 e Glicerol 500 g dm-3 criopreservado. A avaliação foi realizada aos trinta dias observando-se o tamanho e coloração dos calos. Transferiu-se o material para meio de regeneração MS 10 mg dm–3 sacarose, 0,5 mg dm–3 de ANA e 2,0 mg dm–3 de BAP e incubou-se em fotoperíodo de 16 h. Avaliou-se a regeneração aos trinta e quarenta e cinco dias de incubação, os parâmetros foram: crescimento dos calos, número de gemas/calo, número de calos com broto e número de brotos/calo. Na proliferação os calos da Testemunha criopreservado oxidaram, porém, na regeneração, aos trinta dias, apresentaram maior tamanho e número de gemas, e aos quarenta e cinco dias maior número de brotos que os demais tratamentos. Conclui-se que a criopreservação pode ser empregada em calos de sementes de arroz, não afetando sua capacidade regenerativa

Highly Conserved Microchromosomal Organization in Passeriformes Birds Revealed via BAC-FISH Analysis

Passeriformes birds are widely recognized for their remarkable diversity, with over 5700 species described so far. Like most bird species, they possess a karyotype characteristic of modern birds, which includes a bimodal karyotype consisting of a few pairs of macrochromosomes and many pairs of microchromosomes. Although the karyotype is typically 2n = 80, the diploid number can atypically vary greatly, ranging from 56 to approximately 100 chromosomes. In this study, we aimed to understand the extent of conservation of the karyotype’s organizational structure within four species of this group using Bacterial Artificial Chromosomes via Fluorescence In Situ Hybridization (BAC-FISH) with microchromosome probes from Chicken (Gallus gallus) or Zebra Finch (Taeniopygia guttata) per microchromosomes (GGA10-28, except GGA16). By examining the chromosome complement of four passerine species—the Streaked Flycatcher (Myiodynastes maculatus), Shiny Cowbird (Molothrus bonariensis), Southern House Wren (Troglodytes aedon), and Double-collared Seedeater (Sporophila caerulescens)—we discovered a new chromosome number for Southern House Wren. Through FISH experiments, we were able to observe the same pattern of microchromosome organization as in the common ancestor of birds. As a result, we propose a new diploid number for Southern House Wren and confirm the conservation status of microchromosome organization, which may confer evolutionary advantages to this group

Detection of cry1 genes in Bacillus thuringiensis isolates from South of Brazil and activity against Anticarsia gemmatalis (Lepidoptera: Noctuidae)

The bacterium Bacillus thuringiensis (Bt) is characterized by its ability to produce proteic crystalline inclusions during sporulation. Cry1 protein has insecticidal activity and is highly specific to certain insects and not toxic to unrelated insects, plants or vertebrates. In this work, the patogenicity of twelve Bt isolates was tested against Anticarsia gemmatalis, one of the most important insect pests of soybeans. Spore-crystal complex was applied to the surface of artificial diets and the mortality of A. gemmatalis larvae was assessed seven days after each treatment. When compared to a control Bt isolate known by its high toxicity to A. gemmatalis larvae, four novel Bt isolates exhibited even higher toxic activities against the insect, resulting in more than 90% mortality. PCR was used to amplify DNA fragments related to known cry1 genes. Bt strains with high toxicity produced expected PCR products of around 280 bp, whereas non-toxic or low toxic strains did not produce any PCR product or showed amplified fragments of different sizes. Toxic Bt isolates also exhibited an expected protein profile when total protein extracts were evaluated by SDS-PAGE

Bacillus thuringiensis genes an approach to confer insect resistance to plants

Os insetos constituem uma das principais causas de danos à produção agrícola no mundo. O controle de insetos tem sido realizado por meio de agroquímicos e, em muito menor escala, pelo emprego de inseticidas biológicos. As plantas transgênicas resistentes a insetos representam uma nova alternativa no combate aos insetos-praga das lavouras. A bactéria entomopatogênica Bacillus thuringiensis Berlinier (Bt) é a fonte dos genes de resistência nas chamadas plantas-Bt, produzidas comercialmente. No presente trabalho de revisão, são abordados os aspectos relacionados à bactéria Bt como fonte de genes de resistência a insetos-pragas, plantas geneticamente modificadas, vantagens do uso de plantas-Bt, bem como perspectivas dessa ferramenta biotecnológica.Insect pests are a major worldwide cause of damage to agriculture. The control of insect pests was primarily relied on agrochemical and, in a much smaller scale, on biological insecticides. Insect-resistant transgenic plants represent a new alternative to the protection of crops against insect pests. The entomopathogenic bacterium Bacillus thuringiensis (Bt) is the source of resistance genes for the commercial production of the so called Bt-plants. In this review, the main features of Bt as source of resistance genes will be described as well as the main aspects of insect-resistant transgenic plants and advantages of using Btplants

Detection of cry1 genes in Bacillus thuringiensis isolates from South of Brazil and activity against Anticarsia gemmatalis (Lepidoptera: Noctuidae)

The bacterium Bacillus thuringiensis (Bt) is characterized by its ability to produce proteic crystalline inclusions during sporulation. Cry1 protein has insecticidal activity and is highly specific to certain insects and not toxic to unrelated insects, plants or vertebrates. In this work, the patogenicity of twelve Bt isolates was tested against Anticarsia gemmatalis, one of the most important insect pests of soybeans. Spore-crystal complex was applied to the surface of artificial diets and the mortality of A. gemmatalis larvae was assessed seven days after each treatment. When compared to a control Bt isolate known by its high toxicity to A. gemmatalis larvae, four novel Bt isolates exhibited even higher toxic activities against the insect, resulting in more than 90% mortality. PCR was used to amplify DNA fragments related to known cry1 genes. Bt strains with high toxicity produced expected PCR products of around 280 bp, whereas non-toxic or low toxic strains did not produce any PCR product or showed amplified fragments of different sizes. Toxic Bt isolates also exhibited an expected protein profile when total protein extracts were evaluated by SDS-PAGE

Criopreservação de calos de arroz

Cryopreservation is a technique that allows maintaining long-term germoplasma using ultra-reduced temperature. The objective of this study was to evaluate the regeneration seed´s callus of rice cryopreservated. Seeds of rice BRS-7 TAIM, were peeled and desinfested for establishment in vitro, distributed in flasks containing MS (Murashige & Skoog, 1962) 2,5 mg dm-3 of 2,4 D for induction of callus and maintained the temperature of ±25 ºC in the darkness. After twelve days the calluses were cryopreservated in liquid nitrogen for one hour, thawed 37º C and put back in the middle of cultivation for proliferation. It was used fifty callus by treatment: Test, Test cryopreservated, Glycerol 500 g dm-3 and Glycerol 500 g dm-3 cryopreservated. The evaluation of the proliferation was accomplished to the thirty days being observed the size and coloration of the callus. The material was transferred for middle of regeneration MS 10 mg dm–3 sucrose, 0,5 mg dm-3 of ANA and 2,0 mg dm-3 of BAP and it was incubated in fotoperíodo of 16 h. The evaluation of the regeneration was accomplished to the thirty and forty five days of incubation, the parameters were: growth of the callus, sprout and callus number, number of callus with sprout and sprout/callus number. In the proliferation the callus of the treatment Test cryopreservated rusted, however it was observed in the regeneration, to the thirty days, that the same ones presented such adult and number of sprout, and to the forty five days adult number of sprouts than the other treatments. It is ended that the cryopreservation technique can be used in callus of seeds of rice, not affecting the regenerative capacityA criopreservação é uma técnica que mantém germoplasma por longo prazo. Objetivou-se verificar o efeito da criopreservação em nitrogênio líquido na regeneração de calos de arroz induzidos a partir de sementes maduras e avaliar o uso do glicerol como agente crioprotetor. Sementes de arroz BRS-7 TAIM, foram descascadas e desinfestadas, distribuídas em frascos contendo meio MS 2,5 mg dm–3 de 2,4 D para indução de calos e mantidos a temperatura de ±25 ºC no escuro. Após doze dias os calos foram criopreservados em nitrogênio líquido por uma hora, descongelados a 37º C e inoculados no meio de cultivo para proliferação. Utilizou-se cinqüenta calos por tratamento: Testemunha, Testemunha criopreservada, Glicerol 500 g dm-3 e Glicerol 500 g dm-3 criopreservado. A avaliação foi realizada aos trinta dias observando-se o tamanho e coloração dos calos. Transferiu-se o material para meio de regeneração MS 10 mg dm–3 sacarose, 0,5 mg dm–3 de ANA e 2,0 mg dm–3 de BAP e incubou-se em fotoperíodo de 16 h. Avaliou-se a regeneração aos trinta e quarenta e cinco dias de incubação, os parâmetros foram: crescimento dos calos, número de gemas/calo, número de calos com broto e número de brotos/calo. Na proliferação os calos da Testemunha criopreservado oxidaram, porém, na regeneração, aos trinta dias, apresentaram maior tamanho e número de gemas, e aos quarenta e cinco dias maior número de brotos que os demais tratamentos. Conclui-se que a criopreservação pode ser empregada em calos de sementes de arroz, não afetando sua capacidade regenerativ

EFEITO DA RADIAÇÃO GAMA NA GERMINAÇÃO E NO INDICE MITÓTICO EM SEMENTES DE TOMATE-CEREJA Lycopersicon esculentum var. cerasiforme (Dunal) A. Gray.

O tomate-cereja é um dos tipos de tomate muito cultivado e consumido no Brasil. No melhoramento genético, o aumento de variabilidade por indução de mutações é uma das técnicas aplicadas na busca por características agronomicamente interessantes. Neste experimento objetivou-se avaliar os efeitos fisiológicos e citogenéticos de diferentes doses de radiação gama de Co-60 em sementes de tomate cereja. Para tanto, diferentes dosagens de radiação foram testadas (0; 0,1; 0,2; 0,3; 0,5; 0,8; 1,0 e 1,1 kGy) incubados em B.O.D as analisadas foram feitas conforme RAS (Regra de Análise de Sementes). Para determinação dos efeitos fisiológicos foram realizados os testes de germinação, comprimento da parte aérea, e plântulas normal e anormal e para determinação dos efeitos citogenéticos foi avaliado o índice mitótico de células meristemáticas radiculares de tomate cereja. As diferentes doses de radiação testadas não causaram efeitos deletérios ao poder germinativo das sementes de tomate nem induziram aparecimento de plântulas anormais de forma estatisticamente significativa (α = 0,05). Nas doses (0,1; 0,2; 0,3; 0,5; 0,8; 1,0 e 1,1 kGy) de radiação de gama não influenciam a germinação de sementes de tomate cereja e a formação de plântulas anormais. Na avaliação do índice de divisão celular as doses de 0,2 e 0,3 kGy induziram maior atividade mitótica enquanto que a dose de 1,1 kGy causou maior redução no índice mitótico entre as doses testadas

Qualidade fisiológica de sementes de arroz submetidas à radiação gama Physiological quality rice seed submitted to gamma radiation

O objetivo deste trabalho foi avaliar os efeitos da radiação gama (Co60) na qualidade fisiológica de sementes de arroz. O estudo foi realizado em três ensaios. No primeiro ensaio, sementes de arroz foram irradiadas com doses de 0; 1; 2,5 e 5Gy e, para o segundo e o terceiro ensaio, as sementes foram submetidas a envelhecimento acelerado, antes da irradiação. No segundo ensaio, as sementes foram dividas em úmidas e secas após envelhecimento acelerado e, então, foram irradiadas nas doses 0; 1; 2,5 e 5Gy. No terceiro ensaio, as sementes foram secas após o envelhecimento acelerado e irradiadas com doses de 0, 10, 25 e 50Gy. Para avaliação dos efeitos fisiológicos da radiação gama, foram realizados teste de germinação - TG, índice de velocidade de germinação - IVG e crescimento de plantas (comprimento de parte aérea e sistema radicular e massa seca total), em todos os ensaios. Foram determinadas as atividades enzimáticas da fosfatase ácida e alfa amilase nas sementes secas, no segundo ensaio. Os resultados obtidos nos ensaios indicam que as doses de radiação gama estudadas não afetam a qualidade fisiológica das sementes de arroz.<br>The objective of this research was to evaluate the effects of the gamma radiation (Co60) on the physiological quality of rice seeds. The research was carried out through three tests; in the first test rice seeds were irradiated at dosages of 0; 1; 2.5 and 5Gy, while for the second and third tests the seeds were subjected to accelerated aging before being irradiated. For the second test the seeds were divided into wet and dry and both groups subjected to accelerated aging previous to irradiation at dosages of 0; 1; 2.5 and 5Gy. For the third test the seeds were dried after being subjected to accelerated aging, and then irradiated at dosages of 0, 10, 25 and 50Gy. To assess the physiological effects of the gamma radiation, all seeds were tested for germination and their germination speed index recorded. Seedling growth was graded through the measurement of the lengths of the first leaf and seminal root system and total seedling dry weight, across all tests. The enzymatic activity of acid phosphatase and alpha-amylase was measured on dry seeds from the second test. The results from all tests indicate that the applied gamma radiation dosages did not cause any changes to the physiological quality of rice seeds