Sheep tick Ixodes ricinus management on Welsh hill farms of designated conservation importance: implications for nationally declining birds

Impacts of sheep ticks Ixodes ricinus on livestock, gamebirds and wildlife are of concern across Europe. The present study describes livestock and tick management by 36 farmers from three upland sites of conservation importance in North Wales, where farmers consider that ticks have increased during the last 25 years. Sheep, average densities of 2.0 animals per ha were treated with pour‐on acaricides in spring, again in July, and also when removed from the moor in autumn. Given acaricide efficacy rates, sheep were susceptible to tick bites for half the period on the moor. Sheep from 17 farms were examined for ticks. Infestations were similar between farms and in relation to the acaricide used, averaging 9.3 ticks per sheep, although they were lower where the interval between successive acaricide treatments was shorter. Repeated sampling of sheep and red grouse chicks showed no annual difference in tick burdens on grouse chicks, which averaged 6.2 ticks per chick, although there were three‐fold fewer ticks on sheep in 2018 than in previous years. Tick bite rates on sheep and grouse were higher than elsewhere in the U.K. Most farmers interviewed would aim to improve their tick management using longer‐lasting acaricides and treating sheep more frequently, although they would need advice and financial help, which is currently unavailable via Government funded agri‐environment schemes.     

Plant distributions on a saskatchewan prairie

Summary An intensive study of plant species distributions on a Saskatchewan prairie is reported here. Frequency data for fifty-nine vascular species and varieties are presented in association with environmental data relating to soil moisture, water retaining capacity, soil pH and slope position. Secondary consideration is given to light, which is important in the distribution of the understory in dense shrub stands, and soil texture. Soil moisture is shown to be the main determinant of plant species distributions.     

Detection of a Novel Bovine Lymphotropic Herpesvirus

Degenerate PCR primers which amplify a conserved region of the DNA polymerase genes of the herpesvirus family were used to provide sequence evidence for a new bovine herpesvirus in bovine B-lymphoma cells and peripheral blood mononuclear cells (PBMC). The sequence of the resultant amplicon was found to be distinct from those of known herpesvirus isolates. Alignment of amino acid sequences demonstrated 70% identity with ovine herpesvirus 2, 69% with alcelaphine herpesvirus 1, 65% with bovine herpesvirus 4, and 42% with bovine herpesvirus 1. Phylogenetic analysis placed this putative virus within the tumorigenic Gammaherpesvirinae subfamily, and it is tentatively identified as bovine lymphotropic herpesvirus. This novel agent was expressed in vitro from infected PBMC, and cell-free supernatants were used to transfer infection to a bovine B-cell line, BL3. Analysis, with specific PCR primers, of DNA from bovine PBMC and lymphoma cells identified infection in blood of 91% of adult animals (n = 101), 63% of lymphomas (n = 32), and 38% of juveniles (n = 13). Of the adults, herpesvirus infection was present in 94% of animals that were seropositive for bovine leukemia virus (BLV) (n = 63) and in 87% of BLV-seronegative animals (n = 38). Of the seropositive group, 17 animals exhibited persistent lymphocytosis, and 100% of these were herpesvirus positive by PCR. A role for bovine lymphotropic herpesvirus as a cofactor in BLV pathogenesis is considered.     

Effect of Bacillus thuringiensis toxins on the membrane potential of lepidopteran insect midgut cells.

To test whether the ability of Bacillus thuringiensis toxins to form pores in the midgut epithelial cell membrane of susceptible insects correlates with their in vivo toxicity, we measured the effects of different toxins on the electrical potential of the apical membrane of freshly isolated midguts from gypsy moth (Lymantria dispar) and silkworm (Bombyx mori) larvae. In the absence of toxin, the membrane potential, measured with a conventional glass microelectrode, was stable for up to 30 min. It was sensitive to the K+ concentration and the oxygenation of the external medium. Addition of toxins to which L. dispar is highly [CryIA(a) and CryIA(b)] or only slightly [CryIA(c) and CryIC] sensitive caused a rapid, irreversible, and dose-dependent depolarization of the membrane. CryIF, whose toxicity towards L. dispar is unknown, and CryIE, which is at best poorly active in vivo, were also active in vitro. In contrast, CryIB and CryIIIA, a coleopteran-specific toxin, had no significant effect. The basolateral-membrane potential was unaffected by CryIA(a) or CryIC when the toxin was applied to the basal side of the epithelium. In B. mori midguts, the apical-membrane potential was abolished by CryIA(a), to which silkworm larvae are susceptible, but CryIA(b) and CryIA(c); to which they are resistant, had no detectable effect. Although the technique discriminated between active and inactive toxins, the concentration required to produce a given effect varied much less extensively than the sensitivity of gypsy moth larvae, suggesting that additional factors influence the toxins' level of toxicity in vivo.     

Lethal and sub‐lethal impacts of respiratory cryptosporidiosis on Red Grouse,a wild gamebird of economic importance

Respiratory cryptosporidiosis was first diagnosed in Red Grouse Lagopus lagopus scotica, the UK subspecies of Willow Ptarmigan, in 2010. In the next 3 years, respiratory infection by Cryptosporidium baileyi had manifested itself in Grouse on half the moors in northern England and 80% of moors in the North Pennine Hills. In this first account of the impact of respiratory cryptosporidiosis on the population dynamics of a wild bird we fitted 111 diseased and 67 healthy Grouse with radio‐transmitters at two North Pennine moors where disease prevalence averaged 8.1% and monitored their survival and fecundity between autumn 2013 and autumn 2015. Six‐month natural survival rates (excluding shooting) were 0.70 in healthy Grouse, but only 0.44 in diseased females, and 0.22 in diseased males. Some 39% of diseased birds died from their infection, whereas 28% of healthy birds were shot. A similar proportion of each group were killed by predators, either by Stoat Mustela erminea or raptors. Diseased females bred 8 days later than healthy females, but clutch size, egg volume and nesting success did not differ in relation to disease status. Productivity was 43% lower among pairs with a diseased member than in healthy pairs, but appeared impaired only if the female was diseased, not the male. Differences in productivity were related to chick survival rather than the proportion of pairs that reared broods, with chick survival being lower in the 10 days after hatching and again when chicks were 20–50 days old. This latter period was when respiratory infection among chicks was first noticed and the onset of infection may have been a contributing factor to higher mortality during this period. Described levels of respiratory infection reduced the number of birds available to shoot in August by 6%, which represented a mean annual loss of £0.9 million in revenue across managed grouse moors. Likely reductions in shoot economics could escalate should prevalence increase. This disease is a welfare concern and potentially a conservation concern, too, should infection cross to other bird species occupying the same moors.     

Constraints on the transport and glycosylation of recombinant IFN-gamma in Chinese hamster ovary and insect cells.

In this study we compare intracellular transport and processing of a recombinant glycoprotein in mammalian and insect cells. Detailed analysis of the N-glycosylation of recombinant human IFN-gamma by matrix-assisted laser-desorption mass spectrometry showed that the protein secreted by Chinese hamster ovary and baculovirus-infected insect Sf9 cells was associated with complex sialylated or truncated tri-mannosyl core glycans, respectively. However, the intracellular proteins were predominantly associated with high-mannose type oligosaccharides (Man-6 to Man-9) in both cases, indicating that endoplasmic reticulum to cis-Golgi transport is a predominant rate-limiting step in both expression systems. In CHO cells, although there was a minor intracellular subpopulation of sialylated IFN-gamma glycoforms identical to the secreted product (therefore associated with late-Golgi compartments or secretory vesicles), no other intermediates were evident. Therefore, anterograde transport processes in the Golgi stack do not limit secretion. In Sf9 insect cells, there was no direct evidence of post-ER glycan-processing events other than core fucosylation and de-mannosylation, both of which were glycosylation site-specific. To investigate the influence of nucleotide-sugar availability on cell-specific glycosylation, the cellular content of nucleotide-sugar substrates in both mammalian and insect cells was quantitatively determined by anion-exchange HPLC. In both host cell types, UDP-hexose and UDP-N-acetylhexosamine were in greater abundance relative to other substrates. However, unlike CHO cells, sialyltransferase activity and CMP-NeuAc substrate were not present in uninfected or baculovirus-infected Sf9 cells. Similar data were obtained for other insect cell hosts, Sf21 and Ea4. We conclude that although the limitations on intracellular transport and secretion of recombinant proteins in mammalian and insect cells are similar, N-glycan processing in Sf insect cells is limited, and that genetic modification of N-glycan processing in these insect cell lines will be constrained by substrate availability to terminal galactosylation.     

Repercussions of the COVID-19 pandemic on athletes: a cross-sectional study

The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes’ characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports.     

20-HETE-mediated vasoconstriction by hemoglobin-O2 carrier in Sprague-Dawley but not Wistar rats.

Hypothetically either decreased nitric oxide (NO) or increased O(2) could initiate 20-HETE-mediated vasoconstriction associated with hemoglobin-based blood substitutes (HBOC). To test this hypothesis, we infused Tm-Hb, an HBOC with low O(2) affinity, into isoflurane-anesthetized Wistar (W) and Sprague-Dawley (SD) rats after exchanging 20% of their blood with Ringer lactate. For comparison we infused an equal amount of BSA or BSA with N(G)-nitro-L-arginine methyl ester (BSA + NAME). Tm-Hb increased blood pressure (BP) and renal vascular resistance (RVR) equally in W and SD rats. Renal blood flow (RBF; Doppler ultrasound) decreased. BSA decreased RVR and raised glomerular filtration rate. BSA + NAME raised BP, RVR, and GFR. HET0016, an inhibitor of 20-HETE production, blunted BP and RVR responses to Tm-Hb and BSA+NAME in SD but not W rats. Arterial O(2) content with BSA was lower than with Tm-Hb but O(2) delivery was 60% higher with BSA because of higher RBF. BSA raised Po(2) (Oxylite) in cortex and medulla and reduced RVR. Tm-Hb decreased Po(2) and increased RVR. Switching rats from breathing air to 100% O(2) raised intrarenal Po(2) two- to threefold and increased BP and RVR. HET0016 did not alter hyperoxic responses. In conclusion, 20-HETE contributes to vasoconstriction by Tm-Hb in SD but not in W rats, and increased 20-HETE activity results primarily from decreased NO.     

Effects of estradiol and FSH on maturation of the testis in the hypogonadal (hpg) mouse

Background  

The hypogonadal (hpg) mouse is widely used as an animal model with which to investigate the endocrine regulation of spermatogenesis. Chronic treatment of these GnRH-deficient mice with estradiol is known to induce testicular maturation and restore qualitatively normal spermatogenesis. The aim of the current studies was to investigate whether these effects of estradiol are direct effects in the testis, or indirect actions via paradoxical stimulation of FSH secretion from the pituitary gland.