Christina Ramires Ferreira

Large-scale in vitro embryo production and pregnancy rates from Bos taurus, Bos indicus, and indicus-taurus dairy cows using sexed sperm.

Herein we describe a large-scale commercial program for in vitro production of embryos from dairy Bos taurus, Bos indicus, and indicus-taurus donors, using sexed sperm. From 5,407 OPU, we compared the number of recovered oocytes (n = 90,086), viable oocytes (n = 64,826), and embryos produced in vitro from Gir (Bos indicus, n = 617), Holstein (Bos taurus, n = 180), 1/4 Holstein × 3/4 Gir (n = 44), and 1/2 Holstein-Gir (n = 37) crossbred cows, and the pregnancy rate of recipient cows. Viable oocytes were in vitro matured (24 h at 38.8 °C, 5% CO(2) in air) and fertilized by incubating them for 18 to 20 h with frozen-thawed sexed sperm (X-chromosome bearing) from Gir (n = 8) or Holstein (n = 7) sires (2 × 10(6) sperm/dose). Embryos were cultured in similar conditions of temperature and atmosphere as for IVM, with variable intervals of culture (between Days 2 and 5) completed in a portable incubator. All embryos were transferred fresh, after 24 to 72 h of transportation (up to 2,000 km). On average, 16.7 ± 6.3 oocytes (mean ± SEM) were obtained per OPU procedure and 72.0% were considered viable. Total and viable oocytes per OPU procedure were 17.1 ± 4.5 and 12.1 ± 3.9 for Gir cows, 11.4 ± 3.9 and 8.0 ± 2.7 for Holstein cows, 20.4 ± 5.8 and 16.8 ± 5.0 for 1/4 Holstein × 3/4 Gir, and 31.4 ± 5.6 and 24.3 ± 4.7 for 1/2 Holstein-Gir crossbred females (P < 0.01). The mean number of embryos produced by OPU/IVF and the pregnancy rates were 3.2 (12,243/ 3,778) and 40% for Gir cows, 2.1 (2,426/1,138) and 36% for Holstein cows, 3.9 (1,033/267) and 37% for 1/4 Holstein × 3/4 Gir, and 5.5 (1,222/224), and 37% for 1/2 Holstein-Gir. In conclusion, we compared oocyte yield from two levels of indicus-taurus breeds and demonstrated the efficiency of sexed sperm for in vitro embryo production. Culturing embryos during long distance transportation was successful, with potential for international movement of embryos.

Single embryo and oocyte lipid fingerprinting by mass spectrometry

Methods used for lipid analysis in embryos and oocytes usually involve selective lipid extraction from a pool of many samples followed by chemical manipulation, separation and characterization of individual components by chromatographic techniques. Herein we report direct analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) of single and intact embryos or oocytes from various species. Biological samples were simply moisturized with the matrix solution and characteristic lipid (represented by phosphatidylcholines, sphingomyelins and triacylglycerols) profiles were obtained via MALDI-MS. As representative examples, human, bovine, sheep and fish oocytes, as well as bovine and insect embryos were analyzed. MALDI-MS is shown to be capable of providing characteristic lipid profiles of gametes and embryos and also to respond to modifications due to developmental stages and in vitro culture conditions of bovine embryos. Investigation in developmental biology of the biological roles of structural and reserve lipids in embryos and oocytes should therefore benefit from these rapid MALDI-MS profiles from single and intact species.

Phosphatidylcholine and Sphingomyelin Profiles Vary in Bos taurus indicus and Bos taurus taurus In Vitro- and In Vivo-Produced Blastocysts

ABSTRACT Lipid droplets, subspecies (Bos taurus indicus vs. Bos taurus taurus), and in vitro culture are known to influence cryopreservation of bovine embryos. Limited information is available regarding differences in membrane lipids in embryo, such as phosphatidylcholines (PC) and sphingomyelins (SM). The objective of the present study was to compare the profiles of several PC and SM species and relate this information to cytoplasmic lipid levels present in Nellore (B. taurus indicus) and Simmental (B. taurus taurus) blastocysts produced in vitro (IVP) or in vivo (ET). Simmental and IVP embryos had more cytoplasmic lipid content than Nellore and ET embryos (n = 30). Blastocysts were submitted to matrix-assisted laser desorption/ionization mass spectrometry. Differences in the PC profile were addressed by principal component analysis. The lipid species with PC (32:1) and PC (34:1) had higher ion abundances in Nellore embryos, whereas PC (34:2) was higher in Simmental embryos. IVP embryos had less abundant ions of PC (32:1), PC (34:2), and PC (36:5) compared to ET embryos. Moreover, ion abundance of PC (32:0) was higher in both Nellore and Simmental IVP embryos compared to ET embryos. Therefore, mass spectrometry profiles of PC and SM species significantly differ with regard to unsaturation level and carbon chain composition in bovine blastocysts due to subspecies and in vitro culture conditions. Because PC abundances of Nellore and Simmental embryos were distinct (34:1 vs. 34:2), as were those of IVP and ET embryos (32:0 vs. 36:5), they are potential markers of postcryopreservation embryonic survival.

Secretome of the preimplantation human embryo by bottom-up label-free proteomics

AbstractA bottom-up label-free mass spectrometric proteomic strategy was used to analyse the protein profiles of the human embryonic secretome. Culture media samples used for embryonic culture of patients undergoing intracytoplasmic sperm injection cycles were selected as a test case for this exploratory proof-of-principle study. The media were stored after embryo transfer and then pooled into positive (n = 8) and negative (n = 8) implantation groups. The absolute quantitative bottom-up technique employed a multidimensional protein identification technology based on separation by nano-ultra-high pressure chromatography and identification via tandem nano-electrospray ionization mass spectrometry with data-independent scanning in a hydrid QqTOF mass spectrometer. By applying quantitative bottom-up proteomics, unique proteins were found exclusively in both the positive- and negative-implantation groups, which suggest that competent embryos express and secrete unique biomarker proteins into the surrounding culture medium. The selective monitoring of these possible secretome biomarkers could make viable procedures using single-embryo transfer. FigureA bottom-up label-free proteomic mass spectrometric analysis of the human embryo secretome is described. This approach seems to allow quantification and identification of unique proteins related to positive- and negative-implantation groups, which can be further validated as biomarkers for selection and transfer of a single embryo.

Short communication: Identification of subclinical cow mastitis pathogens in milk by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Subclinical mastitis is a common and easily disseminated disease in dairy herds. Its routine diagnosis via bacterial culture and biochemical identification is a difficult and time-consuming process. In this work, we show that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows bacterial identification with high confidence and speed (1 d for bacterial growth and analysis). With the use of MALDI-TOF MS, 33 bacterial culture isolates from milk of different dairy cows from several farms were analyzed, and the results were compared with those obtained by classical biochemical methods. This proof-of-concept case demonstrates the reliability of MALDI-TOF MS bacterial identification, and its increased selectivity as illustrated by the additional identification of coagulase-negative Staphylococcus species and mixed bacterial cultures. Matrix-assisted laser desorption-ionization mass spectrometry considerably accelerates the diagnosis of mastitis pathogens, especially in cases of subclinical mastitis. More immediate and efficient animal management strategies for mastitis and milk quality control in the dairy industry can therefore be applied.

Bacterial identification: from the agar plate to the mass spectrometer

For more than a century, bacteria and fungi have been identified by isolation in culture followed by enzymatic reactions and morphological analyses. The identification of environmental microorganisms, however, remains a challenge because biochemical and staining protocols for bacteria identification are tedious, usually stepwise, can be long (days) and are prone to errors. Molecular techniques based on DNA amplification and/or sequencing provide more secure molecular identification of specific bacteria, but identification based on mass spectrometry (MS), mainly on MALDI-MS, has been shown to be an alternative accurate and fast method able to identify unknown bacteria on the genus, species and even subspecies level based profiles of proteins and peptides derived from whole bacterial cells. Breakthroughs such as non-culture-based identification of bacteria from biological fluids and MS detection of antibiotic resistance have recently been reported. This review provides an overview of the traditional bacterial and fungal identification workflow and discusses the recent introduction of MS as a powerful tool for the identification of microorganisms. Principles and applications of MS, followed by the use of high-quality databases with dedicated algorithms, are discussed for routine microbial diagnostics, mainly in human clinical settings and in veterinary medicine.

Prediction of embryo implantation potential by mass spectrometry fingerprinting of the culture medium

This study has evaluated the performance of a multivariate statistical model to predict embryo implantation potential by processing data from the chemical fingerprinting of culture medium samples used for human embryo culture. The culture medium for 113 embryos from 55 patients undergoing ICSI was collected after embryo transfer. The samples were split into positive (n=29) and negative (n=84) implantation groups according their implantation outcomes (100% or 0% implantation). The samples were individually diluted and analyzed by electrospray ionization mass spectrometry (ESI-MS). The m/z ratios and relative abundances of the major ions in each spectrum were considered for partial least square discriminant analysis. Data were divided into two subsets (calibration and validation), and the models were evaluated and applied to the validation set. A total of 5987 ions were observed in the groups. The multivariate statistical model described more than 82% of the data variability. Samples of the positive group were correctly identified with 100% probability and negative samples with 70%. The culture media used for embryos that were positive or negative for successful implantation showed specific biochemical signatures that could be detected in a fast, simple, and noninvasive way by ESI-MS. To our knowledge, this is the first report that uses MS fingerprinting to predict human embryo implantation potential. This biochemical profile could help the selection of the most viable embryo, improving single-embryo transfer and thus eliminating the risk and undesirable outcomes of multiple pregnancies.

Chemical composition of lipids present in cat and dog oocyte by matrix-assisted desorption ionization mass spectrometry (MALDI- MS).

The aim of the present study was to investigate the level of information on the chemical structures and relative abundances of lipids present in cat and dog oocytes by matrix-assisted laser desorption mass spectrometry (MALDI-MS). The MALDI-MS approach requires a simple analysis workflow (no lipid extraction) and few samples (two or three oocytes per analysis in this work) providing concomitant profiles of both intact phospholipids such as sphingomyelins (SM) and phosphatidylcholines (PC) as well as triacylglycerols (TAG). The lipids were detected in oocytes by MALDI using dihydroxybenzoic acid (DHB) as the matrix. The most abundant lipid present in the MS profiles of bitch and queen oocytes was a PC containing 34 carbons and one unsaturation [PC (34:1)]. Oocytes of these two species are characterized by differences in PC and TAG profiles detected qualitatively as well as by means of principal component analysis (PCA). Cat oocytes were mainly discriminated by more intense C52 and C54 TAG species and a higher number of unsaturations, indicating predominantly linoleic and oleic fatty acyl residues. Comparison of the lipid profile of bitch and queen oocytes with that of bovine oocytes revealed some similarities and also some species specificity: TAG species present in bovine oocytes were also present in bitches and queens; however, a more pronounced contribution of palmitic, stearic and oleic fatty acid residues was noticed in the lipid profile of bovine oocytes. MALDI-MS provides novel information on chemical lipid composition in canine and feline oocytes, offering a suitable tool to concomitantly monitor, in a nearly direct and simple fashion the composition of phospholipids and TAG. This detailed information is highly needed to the development of improved protocols for in vitro culture and cryopreservation of cat and dog oocytes.

Optimal single-embryo mass spectrometry fingerprinting

In pre-implantation embryos, lipids play key roles in determining viability, cryopreservation and implantation properties, but often their analysis is analytically challenging because of the few picograms of analytes present in each of them. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) allows obtaining individual phospholipid profiles of these microscopic organisms. This technique is sensitive enough to enable analysis of individual intact embryos and monitoring the changes in membrane lipid composition in the early stages of development serving as screening method for studies of biology and biotechnologies of reproduction. This article introduces an improved, more comprehensive MALDI-MS lipid fingerprinting approach that considerably increases the lipid information obtained from a single embryo. Using bovine embryos as a biological model, we have also tested optimal sample storage and handling conditions before the MALDI-MS analysis. Improved information at the molecular level is provided by the use of a binary matrix that enables phosphatidylcholines, sphingomyelins, phosphatidylserines, phosphatidylinositols and phosphoethanolamines to be detected via MALDI(±)-MS in both the positive and negative ion modes. An optimal MALDI-MS protocol for lipidomic monitoring of a single intact embryo is therefore reported with potential applications in human and animal reproduction, cell development and stem cell research.

Mass spectrometry fingerprinting of media used for in vitro production of bovine embryos

Using the bovine species as a biological model, direct infusion chip-based nano-electrospray ionization mass spectrometry (nano-ESI-MS) fingerprinting in the positive ion mode is used to obtain fast chemical profiles of media used for in vitro production of bovine embryos. Nano-ESI-MS fingerprinting is useful for characterization and routine quality control requiring no sample pre-separation, being able to differentiate four different media (IVM, IVF, SOF and HSOF) via principal component analysis (PCA). For media stored at +4 degrees C for up to 45 days, no significant (p>0.05) variation was observed in cleavage and blastocyst rate development, as well as in the nano-ESI-MS chemical profiles. For media exposed to a heat shock (60 degrees C for 3 h), no significant decrease (p>0.05) in embryo development rates was observed, but nano-ESI-MS profiles were quite distant from fresh control media in the PCA. For frozen media (-70 degrees C for 2 months), again no significant variation (p>0.05) in embryo development was noticed, but nano-ESI-MS profiles from all media were significantly affected. These results indicate that nano-ESI(+)-MS fingerprinting was able to characterize different media based on their specific chemical profile. The technique seems therefore applicable as a routine quality control assay, detecting, for example, compositional changes after temperature variations that may affect post-transfer embryo viability.