Genetic investigations on backfat thickness and body condition score in German Holstein cattle.

Up to now, little has been known about backfat thickness (BFT) in dairy cattle. The objective of this study was to investigate the lactation curve and genetic parameters for BFT as well as its relationship with body condition score (BCS) and milk yield (MKG). For this purpose, a dataset was analysed including phenotypic observations of 1929 German Holstein cows for BFT, BCS and MKG recorded on a single research dairy farm between September 2005 and December 2022. Additionally, pedigree and genomic information was available. Lactation curves were predicted and genetic parameters were estimated for all traits in first to third lactation using univariate random regression models. For BCS, lactation curves had nadirs at 94 DIM, 101 DIM and 107 DIM in first, second and third lactation. By contrast, trajectories of BFT showed lowest values later in lactation at 129 DIM, 117 DIM and 120 DIM in lactation numbers 1 to 3, respectively. Although lactation curves of BCS and BFT had similar shapes, the traits showed distinct sequence of curves for lactation number 2 and 3. Cows in third lactation had highest BCS, whereas highest BFT values were found for second parity animals. Average heritabilities were 0.315 ± 0.052, 0.297 ± 0.048 and 0.332 ± 0.061 for BCS in lactation number 1 to 3, respectively. Compared to that, BFT had considerably higher heritability in all lactation numbers with estimates ranging between 0.357 ± 0.028 and 0.424 ± 0.034. Pearson correlation coefficients between estimated breeding values for the 3 traits were negative between MKG with both BCS (r = -0.245 to -0.322) and BFT (r = -0.163 to -0.301). Correlation between traits BCS and BFT was positive and consistently high (r = 0.719 to 0.738). Overall, the results of this study suggest that BFT and BCS show genetic differences in dairy cattle, which might be due to differences in depletion and accumulation of body reserves measured by BFT and BCS. Therefore, routine recording of BFT on practical dairy farms could provide valuable information beyond BCS measurements and might be useful, for example, to better assess the nutritional status of cows.

An efficient method for protoplast-mediated production of transformed castor bean (Ricinus communis) lines.

OBJECTIVE: The purpose of this study was to develop a method for the isolation, culture, and PEG-mediated protoplast transfection from leaves of in vitro-grown plants of Ricinus communis. RESULTS: Factors such as the enzymatic composition and the incubation time were evaluated. The enzymatic solution, containing 1.6% Cellulase-R10 and 0.8% Macerozyme-R10, with 16 h of incubation, was the best condition to achieve a high protoplast yield (481.16 × 104 protoplasts/g FW) with a high percentage of viability (95%). The combination and concentration of enzymes have been shown to affect the protoplast isolation efficiency significantly. Furthermore, we found that a higher number of protoplasts (8.5 × 105 protoplast/g FW) was obtained at a longer incubation time, but their viability decreased. We obtained a simple and efficient protocol to isolate protoplast from Ricinus communis leaves and culture. A PEG-mediated protoplast transfection protocol was also established to introduce plasmid DNA into Ricinus communis genotypes cultivated in Colombia. Thus, strengthening advances in the genetic improvement processes for this crop are presented.

Design and Manufacturing of a Disposable, Cyclo-Olefin Copolymer, Microfluidic Device for a Biosensor †.

This contribution outlines the design and manufacturing of a microfluidic device implemented as a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval was carried on after bacteria heat-lysis by an on-chip micro-heater, whose function was characterized at different working parameters. Carbon resistive temperature sensors were tested, characterized and printed on the biochip sealing film to monitor the heating process. Off-chip and on-chip processed RNA were hybridized with capture probes on the reaction chamber surface and identification was achieved by detection of fluorescence tags. The application of the mentioned techniques and materials proved to allow the development of low-cost, disposable albeit multi-functional microfluidic system, performing heating, temperature sensing and chemical reaction processes in the same device. By proving its effectiveness, this device contributes a reference to show the integration potential of fully thermoplastic devices in biosensor systems.

Current molecular techniques for the detection of microbial pathogens.

Traditionally the detection of microbial pathogens in clinical, environmental or food samples has commonly needed the prelevation of cells by culture before the application ofthe detection strategy. This is done to increase cell number thereby overcoming problems associated with the sensitivity of classical detection strategies. However, culture-based methods have the disadvantages of taking longer, usually are more complex and require skilled personnel as well as not being able to detect viable but non cultivable microbial species. A number of molecular methods have been developed in the last 10 to 15 years to overcome these issues and to facilitate the rapid, accurate, sensitive and cost effective identification and enumeration of microorganisms which are designed to replace and/or support classical approaches to microbial detection. Amongst these new methods, ones based on the polymerase chain reaction and nucleic acid hybridization have been shown to be particularly suitable for this purpose. This review generally summarizes some of the current and emerging nucleic acid based molecular approaches for the detection, discrimination andquantification ofmicrobes in environmental, food and clinical samples and includes reference to the recently developing areas of microfluidics and nanotechnology "Lab-on-a-chip".

Polymorphisms in DNA repair genes, chromosome aberrations, and lung cancer.

We have previously investigated the role of polymorphic chemical metabolizing genes in the susceptibility to the development of lung cancer using 110 primary lung cancer patients and 119 matched smoker controls. Together with data from the present study on DNA repair genes, we did not observe significant associations between any single variant genotype for several DNA-repair and chemical-metabolizing genes (XPD [or ERCC2], XRCC1, XRCC3, GSTM1, GSTT1, MPO, and mEH [or EPHX1]) and lung cancer. In the present study, we have further evaluated a nested group of 79 patients and 69 matched controls, and observed that increased chromosome aberrations (CAs) were associated with variant DNA-repair genotypes among both the patient and the control groups, with a significant increase for individuals having the XPD Lys/Gln + Gln/Gln genotypes (P = 0.046). Patients often had significantly increased CAs compared with controls with the same DNA-repair genotype and with similar cigarette smoking habits (< or =40 pack-years or >40 pack-years). Analyses of interactions between the DNA-repair and chemical-metabolizing genes indicated that the most significant interactions were between the repair genotypes and the GSTM1/T1 null genotypes. Significant increases in CA from the interactions were often observed among patients with < or =40 pack-years, but not among those with >40 pack-years. Since some variant DNA-repair genotypes have functional deficits for DNA repair, the association between variant DNA-repair genotypes and increased CAs suggests a risk mechanism for the development of lung cancer, with the DNA-repair genotypes interacting with variant chemical metabolizing genotypes to further increase the risk. The observation that patients had significantly increased CA frequencies compared with controls, irrespective of genotype, suggests that patients have additional factors that contribute to the development of lung cancer.

Assessing DNA damage and health risk using biomarkers.

Carcinogenesis is a multi-stage and prolonged process. At the present time, our knowledge of biological activities along the process is incomplete, therefore, a variety of experimental data are used to assess health risk from exposure to environmental chemicals. However, experimental approaches may not be adequate unless human data are available to support the assessment. In this brief review, benzene (CAS No. 71-43-2), a well-established human leukemogen, will be used as an example to illustrate the challenge in assessing toxicological mechanisms and cancer risk. Benzene has been shown to form DNA-adducts in experimental animals but the adducts have proved elusive of detection in human. Several toxic metabolites of benzene have been identified but the metabolite(s) responsible for the carcinogenic activities is unknown. Furthermore, the significant differences between rodents and human in response to benzene exposure are not understood. Therefore, the bone marrow specificity for the induction of leukemia in human by benzene remains to be elucidated. These complications illustrate the complexity of the assessment process and identify serious information gaps. These information gaps can be viewed as research opportunities to provide more precise data for assessment of toxicological effects and health risk.