Approaches to biosecurity in bovine embryo transfer programs

Although transfer of bovine embryos is much less likely to result in transmission of pathogens than transport of postnatal cattle, the epidemiologic risk associated with bovine embryo transfer merits examination. Much research has validated the efficacy of internationally approved processing protocols to render bovine in vivo-derived embryos free of specified pathogens. The purpose of this review is to summarize current sanitary recommendations for bovine embryo transfer, while emphasizing recent research to develop and validate novel approaches to biosecurity. Continued research will enable the development and validation of novel embryo treatments and culture reagents to minimize requirements for testing of embryo or oocyte donors, and testing of embryo recipients.     

Do Confocal Microscopy and Tardigrades Have a Future Together?

Confocal microscopy was used with acridine orange as a fluorescent probe to optically section Echiniscus testudo (Doyère, 1840) (Echiniscidae). The advantages of the confocal technique and possible developments are discussed.     

A method for efficient isotopic labeling of recombinant proteins

A rapid and efficient approach for preparing isotopically labeled recombinant proteins is presented. The method is demonstrated for ¹³C labeling of the C-terminal domain of angiopoietin-2, ¹⁵N labeling of ubiquitin and for ²H/¹³C/¹⁵N labeling of the Escherichia coli outer-membrane lipoprotein Lpp-56. The production method generates cell mass using unlabeled rich media followed by exchange into a small volume of labeled media at high cell density. Following a short period for growth recovery and unlabeled metabolite clearance, the cells are induced. The expression yields obtained provide a fourfold to eightfold reduction in isotope costs using simple shake flask growths.     

Menaquinone (vitamin K2) biosynthesis in Escherichia coli: synthesis of o-succinylbenzoate does not require the decarboxylase activity of the ketoglutarate dehydrogenase complex

The committed step in menaquinone biosynthesis is the formation of o-succinylbenzoate (OSB). It is presumed to require the reaction of a seven-carbon intermediate of the shikimate pathway with a succinic semialdehyde-thiamin pyrophosphate (TPP) anion, derived by decarboxylation of 2-ketoglutarate. The following evidence indicates that the decarboxylation is not a function of the ketoglutarate dehydrogenase complex but is carried out by a separate activity. (A) Cell-free extracts of Escherichia coli K12 without added TPP lose OSB synthase activity but retain all of the ketoglutarate dehydrogenase complex activities. (B) OSB synthase activity is inhibited by addition of tetrahydro-TPP (th-TPP) to the incubations. The ketoglutarate dehydrogenase complex activities are only inhibited by this analogue after an initial preincubation period. (C) The high molecular weight ketoglutarate dehydrogenase complex can be separated from OSB synthase activity by gel-permeation chromatography on Sepharose CL-6B. Experiment series A and B also provide supporting evidence that TPP does play an important role in menaquinone biosynthesis.     

Production of prostaglandin-like substance at the time of mating in the rat

The amount of prostaglandin-like substance (PG - LS) in the reproductive tract of the male and female rat following mating (p.c.) has been measured and compared with non-mated (control) values. Negligible amounts of PG-LS were detected in the control female tracts but a mean of 2 μg PGE₁ equivalents was detected immediately p.c. The PG-LS is probably generated in the vas deferens since nearly 1 μg PGE₁ equivalents per rat remained there p.c. No other tissue in the male reproductive tract contained significant amounts of PG-LS. Further extraction and chromatography of the PG-LS suggests that the bulk of the activity is due to PGE₂ with a smaller amount being due to PGF_2α.     

Increasing numbers of harbour seals and grey seals in the Solent

Harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) both occur within the UK, but display regional contrasting population trends. While grey seals are typically increasing in number, harbour seals have shown varying trends in recent decades following repeated pandemics. There is a need for monitoring of regional and local populations to understand overall trends. This study utilized a 20‐year dataset of seal counts from two neighboring harbours in the Solent region of south England. Generalized additive models showed a significant increase in the numbers of harbour (mean 5.3–30.5) and grey (mean 0–12.0) seals utilizing Chichester Harbour. Conversely, in Langstone Harbour there has been a slight decrease in the number of harbour seals (mean 5.3–4.0). Accompanying photographic data from 2016 to 18 supports the increase in seal numbers within Chichester Harbour, with a total of 68 harbour and 8 grey seals identified. These data also show evidence of site fidelity of harbour seals in this area, with almost a quarter of animals resighted within the past three years. Overall, this long‐term study indicates an increasing number of both harbour and grey seals within the Solent. However, more research is required to identify the drivers of this trend.     

Cortisol and prolactin modulation of caudal neurosecretory system activity in the euryhaline flounder Platichthys flesus

Previous studies have shown roles for cortisol and prolactin in osmoregulatory adaptation to seawater and freshwater, respectively, in euryhaline fish. This study of the European flounder investigated the potential for these hormones to modulate activity of the caudal neurosecretory system (CNSS), which is thought to be involved in physiological adaptation to changing external salinity. Superfusion of isolated CNSS with either cortisol or prolactin (10 microM; 15 min) led to changes in firing activity in neuroendocrine Dahlgren cells, recorded extracellularly. Cortisol evoked a modest increase in overall firing activity, with the response delayed by 4 h after treatment. The response to prolactin was short latency, continued to build up over the subsequent 4-h wash period, and comprised increased firing activity together with recruitment of previously silent Dahlgren cells. Immunoreactivity for glucocorticoid and prolactin receptors was localised to Dahlgren cells. The CNSS expression level for glucocorticoid-2 receptor mRNA, measured by Q-PCR, was significantly lower in fish fully acclimated to freshwater, compared to seawater. No differences were seen between these two states for prolactin receptor mRNA expression. These results provide evidence for a modulatory action of both hormones on the neurosecretory function of the CNSS.