No abstract

Freeze-drying sperm is an alternative to cryopreservation. Although sperm from various species has been freeze-dried, there are few reports for bovine sperm. The primary objective of this study was to evaluate the protective effect of various freeze-drying media on the structural and functional components of bovine sperm. The media tested were composed of TCM 199 with Hanks salts supplemented with 10% fetal calf serum (FCS) and TCM 199 with Hanks salts supplemented with 10% FCS and 0.2 M trehalose and EGTA solution. The efficiency of each medium on the preservation of freeze-dried sperm structures was evaluated with conventional and electron microscopy, DNA integrity was analyzed by a TUNEL assay, and fertilizing ability of lyophilized sperm was determined with ICSI. Although the plasma membrane was damaged in all media tested, mitochondria were similarly preserved in all freeze-drying treatments. The acrosome was best preserved in the media that contained trehalose (other treatments also conserved this structure). In contrast, media containing EGTA or trehalose most effectively preserved the nuclei in freeze-dried sperm, with only 2 and 5%, respectively, of cells with fragmented DNA. Furthermore, sperm conserved with these media also had higher (P < 0.05) rates of sperm head decondensation (32.5 and 27.5%), pronucleus formation (37.5 and 45.0%) and blastocyst formation (19.4 and 18.3%) than medium supplemented with FCS (15.0, 20.0 and 10.2%, respectively). In conclusion, media with EGTA and trehalose adequately protected bovine sperm during freeze-drying by preserving the viability of their nuclei.

No abstract

No abstract

No abstract

Summary• Nodulated legumes in some of the flooded and seasonally flooded areas of the Pantanal Mato-Grossense wetlands in Brazil are described here.• In the permanently flooded lakes (baias) of the Caracara national park Discolobium pulchellum , Mimosa pellita , Sesbania exasperata and Vigna lasiocarpa (syn. Phaseolus pilosus ) were the most abundant, whereas close to Corumbá, at the edges of the river Paraguai, Neptunia spp. were also common. Adaptations that allow these legumes to fix N 2 in a flooded environment included a floating growth habit, aerenchyma and nodulated adventitious roots.• By contrast, Aeschynomene spp. ( A. ciliata , A. denticulata , A. fluminensis , and A. sensitiva ) were the dominant nodulated legumes in the seasonally flooded pastures of Nhumirim.• Stem-nodulation was commonly observed, particularly on seasonally flooded Aeschynomene and seasonal/permanently flooded Discolobium spp., but also, in a modified form, on floating stems of V. lasiocarpa . The structures of stem and/or root nodules on Aeschynomene spp., Discolobium leptophyllum and V. lasiocarpa are described in detail, and nodulation by D. leptophyllum and Neptunia pubescens is reported for the first time.

The review articles on cell immobilization have been published since 1980 and reflect the general interest in this topic. Immobilized microbial cells create opportunities in a wide range of sectors including environmental pollution control. Compared with suspended microorganism technology, cell immobilization shows many advantages, such as resistance to toxic chemicals. This review presents the potential of immobilized microbial cells for treatment of toxic pollutants in industrial wastewater, the fundamentals, history and advantages of immobilized cells compared with suspended cells, characteristics of support materials and the principal methods of immobilization, with special emphasis for natural immobilization by cell adsorption.

The less differentiated the donor cells are used in nuclear transfer (NT), the more easily are they reprogrammed by the recipient cytoplasm. In this context, mesenchymal stem cells (MSCs) appear as an alternative to donor nuclei for NT. The amniotic fluid and adipose tissue are sources of MSCs that have not been tested for the production of cloned embryos in cattle. The objective of this study was to isolate, characterize, and use MSCs derived from amniotic fluid (MSC-AF) and adipose tissue (MSC-AT) to produce cloned calves. Isolation of MSC-AF was performed using in vivo ultrasound-guided transvaginal amniocentesis, and MSC-AT were isolated by explant culture. Cellular phenotypic and genotypic characterization by flow cytometry, immunohistochemistry, and RT-PCR were performed, as well as induction in different cell lineages. The NT was performed using MSC-AF and MSC-AT as nuclear donors. The mesenchymal markers of MSC were expressed in bovine MSC-AF and MSC-AT cultures, as evidenced by flow cytometry, immunohistochemistry, and RT-PCR. When induced, these cells differentiated into osteocytes, chondrocytes, and adipocytes. Embryo production was similar between the cell types, and two calves were born. The calf from MSC-AT was born healthy, and this fact opens a new possibility of using this type of cell to produce cloned cattle by NT.