Functional integrity of Colossoma macropomum (Cuvier, 1816) sperm cryopreserved with enriched extender solutions

Cryoprotectant solutions are used to protect the sperm from alterations caused by the low temperature in the cryopreservation process. We evaluated the quality of Colossoma macropomum semen after freezing, using dimethyl sulfoxide (DMSO) as a cryoprotectant, combined with two extender solutions (T1 - Solution 1: Glucose 90.0 g/L, Sodium Citrate 6.0 g/L, EDTA 1.5 g/L, Sodium Bicarbonate 1.5 g/L, Potassium Chloride 0.8 g/L, Gentamycin Sulphate 0.2 g/L, and T2 - Solution 2: Glucose 90.0 g/L, ACP(r)-104 10.0 g/L). Motility rate and motility time did not differ between T1 and T2 and were lower than fresh semen. The number of normal sperm was significantly different in treatments T1 (15.1%) and T2 (21.9%), and both showed a reduction in the percentage of normal sperm compared to fresh semen (57.4%). The values found for the rates of fertilization and hatching, mitochondrial functionality and sperm DNA, did not differ between the treatments (T1 and T2). Regarding membrane integrity, there was a higher percentage of spermatozoa with intact membranes in T1 (53.4%) than T2 (43.7%). The extender solutions, combined with 10% DMSO, maintained the sperm DNA intact in almost all the C. macropomumsperm cells, however there was a loss in their functionality.

As soluções crioprotetoras são utilizadas para proteger os espermatozoides das alterações causadas por baixas temperaturas durante o processo de criopreservação. Avaliamos a qualidade do sêmen de Colossoma macropomumapós o congelamento, utilizando dimetilsulfóxido (DMSO) como crioprotetor, combinado com duas soluções diluidoras (T1 - Solução 1: Glicose 90,0 g/L, Citrato de Sódio 6,0 g/L, EDTA 1,5 g/L, Bicarbonato de Sódio 1,5 g/L, Cloreto de Potássio 0,8 g/L, Sulfato de Gentamicina 0,2 g/L, e T2 - Solução 2: Glicose 90,0 g/L, ACP(r)-104 10,0 g/L). A taxa de motilidade (%) e o tempo de motilidade (s) não diferiram entre T1 e T2, porém foram mais baixos do que no sêmen fresco. O número de espermatozoides normais foi significativamente diferente nos tratamentos T1 (15,1%) e T2 (21,9%), e ambos mostraram uma redução na porcentagem de espermatozoides normais, comparado ao sêmen fresco (57,4%). Os valores encontrados para as taxas de fertilização e eclosão, funcionalidade mitocondrial e DNA do esperma, não diferiram entre os tratamentos (T1 e T2). Para a integridade da membrana, houve uma porcentagem mais elevada de espermatozóides com a membrana intacta em T1 (53,4%) do que T2 (43,7%). As soluções diluentes combinadas com DMSO a 10% preservaram o DNA espermático intacto em quase todas as células do sêmen de C. macropomum, mas houve perda na funcionalidade dos mesmos.

Armand M. Karow, Jr.: Looking back.

Armand Karow, Jr. was a devoted scholar of cryobiology who was responsible for the creation of landmark books and many unique observations. Driven into cryobiology by a fascination with organ cryopreservation that dated from his high school days, Karow carried out or contributed to research on the cryopreservation of hearts, kidneys, pancreatic islets, and reproductive cells and tissues. His interests included not only conventional issues in cryobiology such as cryoprotectant permeation kinetics, theories of freezing injury in cells and tissues, and electromagnetic warming of large organs, but also more esoteric questions such as the limits of tolerance of mammalian organs to high pressures, the role of molecular hydration in cell viability, the pharmacological effects of cryoprotectants (which he frequently referred to as drugs), the limits of cryoprotectant tolerance at higher temperatures, and low temperature pharmacology. A look back at some of the discoveries made by Karow and his colleagues reveals many interesting leads whose further investigation could continue to provide valuable new insights in the future.

Sir Alan Sterling Parkes: 10 September 1900 - 17 July 1990.

Alan Parkes was one of the most influential figures in the field of reproductive biology in the twentieth century. He had a huge impact on its growth and development during that time, and the legacy of his work still remains.His research was highly innovative and original because of his imaginative and inquiring mind, which, coupled with an entrepreneurial bent, led him into several very different fields and into unchartered waters. He played a leading role in the spectacular rise of reproductive endocrinology in Britain in the 1920s and 1930s when the nature and activity of many of the reproductive processes in animals and humans and was an essential factor in the development of methods for their control. Even more pioneering was his research in low-temperature biology in the years after World War II. This was sparked off by the discovery that glycerol had a remarkable property of protecting spermatozoa against damage during freezing and storage at very low temperatures. Far-reaching applications arose from this discovery, especially in the preservation of bull semen, which led to a worldwide revolution in artificial insemination in cattle. Later, many other cells and tissues were also successfully frozen, including red blood cells, ovarian tissue and bone marrow, and a new branch of biological science, which became known as 'cryobiology', was born, Effects of deep hypothermia, including freezing, on whole animals were also investigated at that time. Having successfully launched a new area of science, it was characteristic of Alan Parkes to switch to new fields. First he became interested in the influence of pheromones on mammalian reproduction. Then, resuming a long-standing interest in comparative aspects of reproductive physiology in British wild mammals, he became involved in the work of the Nuffield Unit of Tropical Animal Ecology in Uganda, where similar studies were carried out on African animals. Even after retirement from the academic field, he was for some years a consultant to an enterprise in the conservation and captive breeding of green sea turtles in the Cayman Islands. In addition to his research, Alan Parkes was just as influential through the huge amount of work that he did for committees and other activities. Over the years he was on 35 different committees, study groups or advisory groups, and these were concerned with a wide variety of interests. He often served as chairman or secretary and had a great ability to take on a large amount of work and responsibility. He threw himself wholeheartedly into promoting the interests of reproductive biology and was a founding member of both the Society of Endocrinology and the Society for the Study of Fertility. He also played a leading role in the establishment and running of the Journal of Endocrinology and the Journal of Reproduction and Fertility. Getting these journals established often required a considerable amount of financial acumen. One of his special concerns was a long-standing interest in demographic and population issues, which led to his working closely with the International Planned Parenthood Federation and the Family Planning Association. He saw the 'population explosion' as a growing threat to the environment and to human welfare, and he was an outstanding proponent of measures to effect population control. Sometimes this led him into controversial areas. He spoke strongly in support of women's right to abortion and questioned the morality of expensive measures to overcome infertility. Throughout his life he was a prolific and lucid writer and his many publications remain a lasting monument to his contribution to science. He entitled the first volume of his autobiography Off-beat biologist, which is perhaps a very apt description of this remarkable man.