The relative importance of COVID-19 pandemic impacts on biodiversity conservation globally

The COVID-19 pandemic has had an enormous impact on almost all aspects of human society and endeavor; the natural world and its conservation have not been spared. Through a process of expert consultation, we identified and categorized, into 19 themes and 70 subthemes, the ways in which biodiversity and its conservation have been or could be affected by the pandemic globally. Nearly 60% of the effects have been broadly negative. Subsequently, we created a compendium of all themes and subthemes, each with explanatory text, and in August 2020 a diverse group of experienced conservationists with expertise from across sectors and geographies assessed each subtheme for its likely impact on biodiversity conservation globally. The 9 subthemes ranked highest all have a negative impact. These were, in rank order, governments sidelining the environment during their economic recovery, reduced wildlife-based tourism income, increased habitat destruction, reduced government funding, increased plastic and other solid waste pollution, weakening of nature-friendly regulations and their enforcement, increased illegal harvest of wild animals, reduced philanthropy, and threats to survival of conservation organizations. In combination, these impacts present a worrying future of increased threats to biodiversity conservation but reduced capacity to counter them. The highest ranking positive impact, at 10, was the beneficial impact of wildlife-trade restrictions. More optimistically, among impacts ranked 11-20, 6 were positive and 4 were negative. We hope our assessment will draw attention to the impacts of the pandemic and, thus, improve the conservation community's ability to respond to such threats in the future.

Post COVID-19: a solution scan of options for preventing future zoonotic epidemics

The crisis generated by the emergence and pandemic spread of COVID-19 has thrown into the global spotlight the dangers associated with novel diseases, as well as the key role of animals, especially wild animals, as potential sources of pathogens to humans. There is a widespread demand for a new relationship with wild and domestic animals, including suggested bans on hunting, wildlife trade, wet markets or consumption of wild animals. However, such policies risk ignoring essential elements of the problem as well as alienating and increasing hardship for local communities across the world, and might be unachievable at scale. There is thus a need for a more complex package of policy and practical responses. We undertook a solution scan to identify and collate 161 possible options for reducing the risks of further epidemic disease transmission from animals to humans, including potential further SARS-CoV-2 transmission (original or variants). We include all categories of animals in our responses (i.e. wildlife, captive, unmanaged/feral and domestic livestock and pets) and focus on pathogens (especially viruses) that, once transmitted from animals to humans, could acquire epidemic potential through high rates of human-to-human transmission. This excludes measures to prevent well-known zoonotic diseases, such as rabies, that cannot readily transmit between humans. We focused solutions on societal measures, excluding the development of vaccines and other preventive therapeutic medicine and veterinary medicine options that are discussed elsewhere. We derived our solutions through reading the scientific literature, NGO position papers, and industry guidelines, collating our own experiences, and consulting experts in different fields. Herein, we review the major zoonotic transmission pathways and present an extensive list of options. The potential solutions are organised according to the key stages of the trade chain and encompass solutions that can be applied at the local, regional and international scales. This is a set of options targeted at practitioners and policy makers to encourage careful examination of possible courses of action, validating their impact and documenting outcomes.

Post COVID-19: a solution scan of options for preventing future zoonotic epidemics

The crisis generated by the emergence and pandemic spread of COVID-19 has thrown into the global spotlight the dangers associated with novel diseases, as well as the key role of animals, especially wild animals, as potential sources of pathogens to humans. There is a widespread demand for a new relationship with wild and domestic animals, including suggested bans on hunting, wildlife trade, wet markets or consumption of wild animals. However, such policies risk ignoring essential elements of the problem as well as alienating and increasing hardship for local communities across the world, and might be unachievable at scale. There is thus a need for a more complex package of policy and practical responses. We undertook a solution scan to identify and collate 161 possible options for reducing the risks of further epidemic disease transmission from animals to humans, including potential further SARS-CoV-2 transmission (original or variants). We include all categories of animals in our responses (i.e. wildlife, captive, unmanaged/feral and domestic livestock and pets) and focus on pathogens (especially viruses) that, once transmitted from animals to humans, could acquire epidemic potential through high rates of human-to-human transmission. This excludes measures to prevent well-known zoonotic diseases, such as rabies, that cannot readily transmit between humans. We focused solutions on societal measures, excluding the development of vaccines and other preventive therapeutic medicine and veterinary medicine options that are discussed elsewhere. We derived our solutions through reading the scientific literature, NGO position papers, and industry guidelines, collating our own experiences, and consulting experts in different fields. Herein, we review the major zoonotic transmission pathways and present an extensive list of options. The potential solutions are organised according to the key stages of the trade chain and encompass solutions that can be applied at the local, regional and international scales. This is a set of options targeted at practitioners and policy makers to encourage careful examination of possible courses of action, validating their impact and documenting outcomes.

Biodiversity conservation as a promising frontier for behavioural science

Human activities are degrading ecosystems worldwide, posing existential threats for biodiversity and humankind. Slowing and reversing this degradation will require profound and widespread changes to human behaviour. Behavioural scientists are therefore well placed to contribute intellectual leadership in this area. This Perspective aims to stimulate a marked increase in the amount and breadth of behavioural research addressing this challenge. First, we describe the importance of the biodiversity crisis for human and non-human prosperity and the central role of human behaviour in reversing this decline. Next, we discuss key gaps in our understanding of how to achieve behaviour change for biodiversity conservation and suggest how to identify key behaviour changes and actors capable of improving biodiversity outcomes. Finally, we outline the core components for building a robust evidence base and suggest priority research questions for behavioural scientists to explore in opening a new frontier of behavioural science for the benefit of nature and human wellbeing.

Think Before You Act: Improving the Conservation Outcomes of CITES Listing Decisions

The CITES treaty is the major international instrument designed to safeguard wild plants and animals from overexploitation by international trade. CITES is now approaching 50 years old, and we contend that it is showing its age. In stark contrast to most environmental policy arenas, CITES does not require, encourage, or even allow for, consideration of the impacts of its key decisions—those around listing species in the CITES Appendices. Decisions to list species in CITES are based on a simplistic set of biological and trade criteria that do not relate to the impact of the decision, and have little systematic evidentiary support. We explain the conservation failures that flow from this weakness and propose three key changes to the CITES listing process: (1) development of a formal mechanism for consideration by Parties of the likely consequences of species listing decisions; (2) broadening of the range of criteria used to make listing decisions; and (3) amplification of the input of local communities living alongside wildlife in the listing process. Embracing these changes will help to ensure CITES decisions more effectively respond to the needs of wildlife in today’s highly complex and dynamic conservation context.

Reduced activity in a liaison psychiatry service during the peak of the COVID-19 pandemic: Comparison with 2019 data and characterisation of the SARS-COV-2 positive cohort

Introduction

The COVID-19 pandemic led to changes in how healthcare was accessed and delivered. It was suggested that COVID-19 will lead to an increased delirium burden in its acute phase, with variable effect on mental health in the longer term. Despite this, there are limited data on the direct effects of the pandemic on psychiatric care.

Objectives

1) describe the mental health presentations of a diverse acute inpatient population, 2) compare findings with the same period in 2019, 3) characterise the SARS-CoV-2 positive cohort of patients.

Methods

We present a descriptive summary of the referrals to a UK psychiatric liaison department during the exponential phase of the pandemic, and compare this to the same period in 2019.

Results

show a 40.3% reduction in the number of referrals in 2020, with an increase in the proportion of referrals for delirium and psychosis. One third (28%) of referred patients tested positive for COVID-19 during their admission, with 39.7% of these presenting with delirium as a consequence of their COVID-19 illness. Our data indicate decreased clinical activity for our service during the pandemic’s peak. There was a marked increase in delirium, though in no other psychiatric presentations.

Conclusions

In preparation for further exponential rises in COVID-19 cases, we would expect seamless integration of liaison psychiatry teams in general hospital wards to optimise delirium management in patients with COVID-19. Further consideration should be given to adequate staffing of community and crisis mental health teams to safely manage the potentially increasing number of people reluctant to visit the emergency department.

A 2021 Horizon Scan of Emerging Global Biological Conservation Issues

We present the results from our 12th annual horizon scan of issues likely to impact biological conservation in the future. From a list of 97 topics, our global panel of 25 scientists and practitioners identified the top 15 issues that we believe society may urgently need to address. These issues are either novel in the biological conservation sector or represent a substantial positive or negative step-change in impact at global or regional level. Six issues, such as coral reef deoxygenation and changes in polar coastal productivity, affect marine or coastal ecosystems and seven relate to human and ecosystem-level responses to climate change. Identification of potential forthcoming issues for biological conservation may enable increased preparedness by researchers, practitioners, and decision-makers.

One hundred questions of importance to the conservation of global biological diversity

We identified 100 scientific questions that, if answered, would have the greatest impact on conservation practice and policy. Representatives from 21 international organizations, regional sections and working groups of the Society for Conservation Biology, and 12 academics, from all continents except Antarctica, compiled 2291 questions of relevance to conservation of biological diversity worldwide. The questions were gathered from 761 individuals through workshops, email requests, and discussions. Voting by email to short-list questions, followed by a 2-day workshop, was used to derive the final list of 100 questions. Most of the final questions were derived through a process of modification and combination as the workshop progressed. The questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. We anticipate that these questions will help identify new directions for researchers and assist funders in directing funds.

The effect of mechanical strain on protease production by keratinocytes

BACKGROUND

Intact skin is under constant tension, transmitted from the underlying dermis, but when tension is lost (i.e. upon wounding) protease activity is upregulated.

OBJECTIVES

To investigate the effect of mechanical strain on protease production by both normal and transformed keratinocytes in vitro.

METHODS

Keratinocytes were seeded on to membranes precoated with either type I or type IV collagen. After 48 h medium was replaced with serum-free medium and mechanical strain was applied.

RESULTS

Mechanical strain resulted in decreased urokinase-type plasminogen activator (uPA) production by normal human keratinocytes (P<0.05) but increased production by transformed keratinocytes (P<0.05) cultured on type I and type IV collagen.

CONCLUSIONS

Differential production of uPA by normal and transformed keratinocytes is relevant in the context of normal function, wound healing and tumorigenesis.

Human ovarian surface epithelial cells immortalized with hTERT maintain functional pRb and p53 expression

OBJECTIVE

Cell immortalization is considered to be a prerequisite status for carcinogenesis. Normal human ovarian surface epithelial (OSE) cells, which are thought to be the origin of most of human ovarian carcinomas, have a very limited lifespan in culture. Establishment of immortalized OSE cell lines has, in the past, required inactivation of pRb and p53 functions. However, this often leads to increased chromosome instability during prolonged culture.

MATERIALS AND METHODS

In this study, we have used a retroviral infection method to overexpress human telomerase reverse transcriptase (hTERT) gene, in primary normal OSE cells, under optimized culture conditions.

RESULTS

In vitro and in vivo analysis of hTERT-immortalized cell lines confirmed their normal epithelial characteristics. Gene expression profiles and functional analysis of p16(INK4A), p15(INK4B), pRb and p53 confirmed the presence of their intact functions. Our study suggests that inactivation of pRb and p53 is not necessary for OSE immortalization. Furthermore, down-regulation of p15(INK4B) in the immortalized cells may indicate a functional role for this protein in them.

CONCLUSION

These immortal OSE cell lines are likely to be an important tool for studying human OSE biology and carcinogenesis.

Cell-based delivery of cytokines allows for the differentiation of a doxycycline inducible oligodendrocyte precursor cell line in vitro

BACKGROUND

Stem cells, having the property of self renewal, offer the promise of lifelong repair of damaged tissue. However, somatic tissue-committed primary stem cells are rare and difficult to expand in vitro. Genetically modified stem-like cells with the ability to expand conditionally provide a valuable tool with which to study stem cell biology, especially the cellular events of proliferation and differentiation. In addition, stem cells may be appropriate candidates for therapeutic applications.

METHODS

Double transgenic mice possesing SV40 T antigen (Tag) under the control of the reverse tetracycline-transactivator (rtTA) were used to establish cell lines. One brain cell line was partially characterized by DNA sequencing, morphology, antigen expression using flow cytometry, confocal microscopy, and electrophysiology using the patch clamp technique. Cell cycle analysis was performed using propidium iodide staining; cell viability and H3-thymidine incorporation assays. The ability of this cell line to differentiate was assessed by confocal microscopy following co-culture with stem cells secreting cytokines.

RESULTS

We report here the establishment and partial characterization of a cell line derived from the brain tissue of rtTA-SV40 Tag transgenic mice. Analysis of the morphology and antigen markers has shown that this cell line mimics some aspects of primary glial precursors. The results of electrophysiology are consistent with this and suggest that the cell line is derived from O2A glial precursor cells. Cell cycle progression of this cell line is doxycycline-dependent. In the absence of doxycycline, cells become apoptotic. Differentiation into mature type 2 astrocytes and (precursor) oligodendrocytes can be induced upon withdrawal of doxycycline and addition of epithelial stem cells secreting cytokine, such as hIL3 (human Interleukine 3) or hIL6 to the culture. In contrast, co-culturing with hCNTF (human Ciliary NeuroTrophic Factor)-secreting epithelial stem cells did not induce them to mature into progeny cell types.

CONCLUSION

The differentiation of this O2A glial precursor line does not occur automatically in culture. Additional external help is required from the cell-based delivery of appropriate transgenic cytokines. Withdrawal of doxycycline from the culture medium removes the proliferation signals and induces a fatal outcome.

Evidence for redundancy in cysteine biosynthesis in Rhizobium leguminosarum RL3841: analysis of a cysE gene encoding serine acetyltransferase

A cysE gene encoding a serine acetyltransferase (SAT) potentially involved in the biosynthesis of cysteine was identified approximately 4 kb upstream of the previously described aapJQMP gene cluster that encodes an amino acid permease in Rhizobium leguminosarum strain 3841. The gene exhibits >40% identity to the family of SATs containing N-terminal extensions that have been described for other bacteria and plants. The ORF has three possible translation initiation sites which potentially encode polypeptides of 311, 277 and/or 259 amino acid residues, respectively. All three ORFs complemented the cysE mutation in an Escherichia coli cysteine auxotroph, strain JM39. Insertion of Tn5-lacZ into cysE in the genome of R. leguminosarum (strain RU632) lowered SAT activity in crude extracts by >95%. However, RU632 was not a cysteine auxotroph, which suggests that R. leguminosarum possesses some redundancy in cysteine biosynthesis. Additional copies of cysE could not be detected in the genome when the R. leguminosarum cysE gene was used as a hybridization probe. Therefore it is possible that R. leguminosarum possesses an alternative pathway for cysteine biosynthesis which avoids O-acetylserine. Strain RU632 was unaffected in its ability to nodulate Pisum sativum, and the nodules were effective for N(2) fixation (measured by C(2)H(2) reduction). Transcriptional activity of cysE was determined by measuring the beta-galactosidase arising from cysE::Tn5-lacZ fusions. Maximal levels of expression were observed during early exponential growth and were not influenced by the level of sulphur (supplied as sulphate). However, transcription was repressed by approximately twofold in ammonium-grown, as opposed to glutamate-grown, cultures. Repression by ammonium was not seen in a strain defective for ntrC.

A role for mitogen-activated protein kinase activation by integrins in the pathogenesis of psoriasis

In normal epidermis, beta1 integrin expression is confined to the basal layer, whereas in hyperproliferative epidermis, integrins are also expressed in the suprabasal layers. Transgenic mice in which integrins are expressed suprabasally via the involucrin promoter have a sporadic psoriatic phenotype; however, the mechanism by which integrins contribute to the pathogenesis of psoriasis is unknown. We observed activation of mitogen-activated protein kinase (MAPK) in basal and suprabasal keratinocytes of human and transgenic mouse psoriatic lesions and healing mouse skin wounds, correlating in each case with suprabasal integrin expression. Phenotypically normal human and transgenic mouse epidermis did not contain activated MAPK. Transgene-positive keratinocytes produced more IL-1alpha than controls did, and keratinocyte MAPK could be activated by ligation of suprabasal integrins or treatment with IL-1alpha. Constitutive activation of MAPK increased the growth rate of human keratinocytes and delayed the onset of terminal differentiation, recreating many of the histological features of psoriatic epidermis. We propose that activation of MAPK by integrins, either directly or through increased IL-1alpha production, is responsible for epidermal hyperproliferation in psoriasis and wound healing, and that the sporadic phenotype of the transgenic mice may reflect the complex mechanisms by which IL-1 release and responsiveness are controlled in skin.

Implementation of enhanced dynamic wedge in the focus rtp system

The FOCUS RTP system implementation of Varian's enhanced dynamic wedge (EDW) is presented. Calculations of both dose distributions and wedge factors (WFs) are based on segmented treatment tables (STTs). Calculating dose requires a "transmission matrix" derived from an STT to model the modified fluence from the source. The dose calculation is then performed using either the Clarkson or convolution/superposition algorithms. An initial "primary dose/monitor unit (MU) fraction" WF estimate at the weight point of symmetric and asymmetric fields is calculated from the STT as the ratio of MU delivered on the axis of the weight point divided by total MU delivered for the treatment field. In our approach, we go beyond this initial estimate with a "scatter dose" correction. This requires measured 60 degrees WFs for 5 fields. Scatter corrections derived from measured WFs are interpolated for other wedge angles and field sizes in much the same way as arbitrary wedge angle STTs are derived from a "golden STT" using the "ratio of tangents" formalism. Dose comparisons with measured distributions show good agreement to within 3% or 3 mm for 6-MV beams and all EDW angles. Agreement with measurements to within 1% is obtained for WFs in all symmetric and asymmetric fields for 6- and 10-MV beams. For large wedge angles and field sizes, this represents a significant improvement over the 3% to 4% errors often observed using the MU fraction model alone.

beta1 integrins regulate keratinocyte adhesion and differentiation by distinct mechanisms

In keratinocytes, the beta1 integrins mediate adhesion to the extracellular matrix and also regulate the initiation of terminal differentiation. To explore the relationship between these functions, we stably infected primary human epidermal keratinocytes and an undifferentiated squamous cell carcinoma line, SCC4, with retroviruses encoding wild-type and mutant chick beta1 integrin subunits. We examined the ability of adhesion-blocking chick beta1-specific antibodies to inhibit suspension-induced terminal differentiation of primary human keratinocytes and the ability of the chick beta1 subunit to promote spontaneous differentiation of SCC4. A D154A point mutant clustered in focal adhesions but was inactive in the differentiation assays, showing that differentiation regulation required a functional ligand-binding domain. The signal transduced by beta1 integrins in normal keratinocytes was "do not differentiate" (transduced by ligand-occupied receptors) as opposed to "do differentiate" (transduced by unoccupied receptors), and the signal depended on the absolute number, rather than on the proportion, of occupied receptors. Single and double point mutations in cyto-2 and -3, the NPXY motifs, prevented focal adhesion targeting without inhibiting differentiation control. However, deletions in the proximal part of the cytoplasmic domain, affecting cyto-1, abolished the differentiation-regulatory ability of the beta1 subunit. We conclude that distinct signaling pathways are involved in beta1 integrin-mediated adhesion and differentiation control in keratinocytes.

Optimised retroviral infection of human epidermal keratinocytes: long-term expression of transduced integrin gene following grafting on to SCID mice

Previous attempts to achieve long-term gene expression in retrovirally transduced human epidermal keratinocytes in vivo have been largely unsuccessful. This has been variously attributed to a failure to target epidermal stem cells, suboptimal grafting conditions or inactivation of the retroviral vector. In an attempt to overcome these problems we expressed the chick beta 1 integrin subunit in primary human epidermal keratinocytes, which allowed us to monitor retroviral gene expression on a cell-by-cell basis. We describe optimised methods for selecting high-titre amphotropic packaging cells and for infecting keratinocytes in culture. When transduced cells were grafted into mice, graft survival was comparable in nude and SCID mice, but it was essential to combine the keratinocytes with a dermal substrate. Using these methods the majority of keratinocytes expressed the chick beta 1 integrin subunit for at least 16 weeks after grafting. We conclude that epidermal keratinocytes are attractive recipient cells for gene therapy.

The bombesin/GRP receptor transfected into Rat-1 fibroblasts couples to phospholipase C activation, tyrosine phosphorylation of p125FAK and paxillin and cell proliferation

Bombesin elicits multiple signalling pathways in various cell types. It is not clear, however, whether these responses are mediated by a single receptor subtype or by different subtypes that couple preferentially to specific pathways. To resolve this we transfected the mouse bombesin/GRP receptor into Rat-1 fibroblasts and investigated the pathways activated by bombesin. Expression of the transfected receptors was verified by binding of (125I)GRP and two clones were selected, BOR5 and BOR15. Bombesin stimulation of BOR5 and BOR15 cells caused intracellular Ca2+ mobilisation and increased the phosphorylation of 80K/MARCKS, a prominent protein kinase C substrate. The transfected receptor conferred a proliferative response to bombesin demonstrated by incorporation of (3H) thymidine after 18 h and an increase in total cell numbers after 1-2 days. In BOR5 and BOR15 cells, bombesin rapidly stimulated the tyrosine phosphorylation of multiple proteins Mr 110 000-130 000 and 70 000-80 000 including p125fak and paxillin, at low concentrations (half maximum 0.3 nM). The specific bombesin/GRP receptor antagonist, D-F5-Phe6, D-Ala11-Bombesin (6-13)OMe, inhibited all the above responses. These results show that phospholipase C activation, cell growth and tyrosine phosphorylation emanate from a single class of bombesin receptor.

Mitogenic signaling by transfected neuromedin B receptors in Rat-1 cells

The rat neuromedin B (NMB) receptor was expressed in Rat-1 fibroblasts to elucidate the signaling pathways and mitogenic effects mediated by this seven-transmembrane domain receptor. Receptor expression was verified by ligand binding and Ca2+ mobilization, which were blocked by the NMB receptor antagonist D-Nal-Cys-Tyr-D-Trp-Orn-Val-Cys-Nal-NH2. NMB acted as a potent growth factor promoting DNA synthesis and cell proliferation in serum-free medium in Rat-1 cells transfected with the NMB receptor. Prior to DNA synthesis, NMB stimulated phosphorylation of 80K/MARCKS, a major substrate of protein kinase C, which could be prevented by the selective protein kinase C inhibitor GF 109203X. Furthermore, NMB induced a rapid p42MAPK activation and tyrosine phosphorylation of multiple proteins including p125FAK and paxillin. The half-maximal concentrations (EC50) of NMB required to induce DNA synthesis (0.7-0.9 nM) and cell proliferation (0.7-1 nM) paralleled the Kd for 125I-[D-Tyr0]NMB binding and the EC50 values for the induction of the early signaling events. Thus, NMB can activate multiple signal transduction pathways and act as a sole mitogen through its receptor expressed in Rat-1 fibroblasts.

The human CCKB/gastrin receptor transfected into rat1 fibroblasts mediates activation of MAP kinase, p74raf-1 kinase, and mitogenesis

The human cholecystokinin (CCK)B/gastrin receptor was stably transfected into Rat1 fibroblasts to examine the signaling pathways mediated by this seven-transmembrane, G protein-linked receptor. We report here that binding of CCK-8 or gastrin to the CCKB/gastrin receptor induced phosphoinositide breakdown and led to a rapid, transient, and concentration-dependent increase in intracellular Ca2+, which was completely blocked by a specific CCKB receptor antagonist. The peptides also stimulated tyrosine phosphorylation of focal adhesion kinase (p125FAK) and paxillin. Both CCK-8 and gastrin induced a dose- and time-dependent activation of MAP kinase and p74raf-1 kinase in the transfected Rat1 cells. These effects could be dissociated from protein kinase C activation and were not dependent on a functional Gi protein. Finally, both CCK-8 and gastrin induced DNA synthesis in Rat1 cells transfected with the human CCKB/gastrin receptor through a pertussis toxin-insensitive pathway. These results indicate that the neuropeptides gastrin and CCK can activate multiple signal transduction pathways and act as sole mitogens by binding to the CCKB/gastrin receptor transfected into Rat1 fibroblasts.

Overexpression of the myristoylated alanine-rich C-kinase substrate in Rat1 cells increases sensitivity to calmodulin antagonists

The acidic 80-kDa myristoylated alanine-rich C-kinase substrate protein (80-kDa MARCKS) is the major protein-kinase-C substrate in rodent fibroblasts. To elucidate its function, we transfected the cDNA coding for the 80-kDa MARCKS protein into Rat1 fibroblasts. One clone, called Rat1-80K, expressed 4.5 +/- 0.8-fold and 9.5 +/- 1.5-fold higher levels of 80-kDa MARCKS protein under quiescent and growing conditions, respectively, compared to mock or untransfected control cells. Southern-blot and Northern-blot analyses of Rat1-80K showed intact integration and correct transcription of the introduced 80-kDa MARCKS gene. The overexpressed 80-kDa MARCKS protein was phosphorylated and translocated from the membrane to the cytoplasmic fraction. Since 80-kDa MARCKS has been described as a calmodulin-binding protein in in vitro studies, we investigated the effects of the calmodulin antagonists N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and triflouperazine on the entry into the S-phase of the cell cycle in intact cells. DNA synthesis by Rat1-80K cells was more sensitive to either N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide or triflouperazine than that of control cells. Our results suggest that overexpression of the 80-kDa MARCKS protein reduces the free concentration of calmodulin in the cell.

Expression of the major protein kinase C substrate, the acidic 80-kilodalton myristoylated alanine-rich C kinase substrate, increases sharply when Swiss 3T3 cells move out of cycle and enter G0

The expression of the major protein kinase C (PKC) substrate, originally called "80K" for acidic SDS/PAGE-observed 80-kDa PKC substrate and now called "MARCKS" for myristoylated alanine-rich C kinase substrate, in Swiss 3T3 fibroblasts changes strikingly (15- to 22-fold) during transitions of cell growth. Quiescent cells in G0 express high levels of MARCKS mRNA and protein. However, plating these cells in fresh medium at low density to stimulate multiple rounds of cell division caused a striking down-regulation of MARCKS expression. The mRNA level declined to a minimum of 4.5% compared with quiescent control cells 6 hr after plating, and protein levels declined during the same period to 6.5% of the control value. This rapid down-regulation was independent of PKC activation and length of exposure to trypsin (1-10 min) but required plating in medium containing fresh serum. MARCKS mRNA and protein levels remained down-regulated for 3 days, during which time the cells were actively progressing through the cell cycle as judged by fluorescence-activated cell sorting analysis. However, on reaching quiescence, the expression of MARCKS mRNA and protein increased markedly. Furthermore, the rate of recovery of MARCKS mRNA and protein levels was shown to be dependent on the supply of serum-derived growth factors in the medium. Addition of hydroxyurea to arrest the cells in S phase or at the G1/S boundary rather than G0 completely prevented the recovery of MARCKS protein. The down-regulation of MARCKS following plating and its serum-dependent recovery was also demonstrated in tertiary cultures of mouse embryo fibroblasts. The results suggest that MARCKS may play a role in the regulation of entry and exit of cells from G0.

Whole-cell recording of neuroblastoma x glioma cells during downregulation of a major substrate, 80K/MARCKS, of protein kinase C

Differentiated neuroblastoma cells exhibit both the delayed rectifier potassium current (IK) and the M-current (IM). The present study was designed to determine the roles of protein kinase C (PKC) and of the calmodulin-binding protein 80K/MARCKS, a prominent substrate for PKC and possible regulator of these currents. Neuroblastoma x glioma (NG108-15) hybrid cells transfected with m1 muscarinic receptors were grown with 1% fetal bovine serum (FBS) without the prostaglandin E1 (PGE1) and isobutylmethylxanthine (IBMX) usually added in preparation for electrophysiological studies. Under these conditions, the usual pleomorphism was largely abolished, leaving two populations of small cells with stellate and spherically symmetrical geometries. Whole-cell patch clamping indicated that the two cell types had identical electrophysiological properties, displaying: IK, a small current through a "T-like" Ca2+ channel, and no M-current. Stimulation with carbachol shifted the distribution of cells to a more stellate morphology within 24 hr and later (after 48 hr) reduced the PKC substrate 80K/MARCKS by 22 +/- 7%. In contrast to the stimulation of IK observed with cardiac cells, PKC activation produced only a small inhibition of IK, which was independent of carbachol pretreatment. Thus, PKC and 80K/MARCKS can be dissociated from the regulation of IK in neuroblastoma cells.

Relationship between the major protein kinase C substrates acidic 80-kDa protein-kinase-C substrate (80K) and myristoylated alanine-rich C-kinase substrate (MARCKS). Members of a gene family or equivalent genes in different species

Two major protein-kinase-C (PKC) substrates have been described in the literature; an 87-kDa bovine and human PKC substrate, called MARCKS, and an acidic 80-kDa PKC substrate, isolated from rat brain and Swiss 3T3 cells, termed 80K. Since there is only 66-74% sequence similarity between MARCKS and 80K, we have further investigated their relationship in this study. Southern-blot experiments with gene-specific probes demonstrated the presence of the 80K, but not MARCKS, gene in the mouse genome. Furthermore, polymerase-chain-reaction (PCR) analyses using three pairs of primers that specifically recognise either 80K, MARCKS or conserved sequences of both genes, revealed the presence of only the 80K gene in the mouse and rat genomes and only the MARCKS gene in the bovine and human genomes with mRNA expression in the corresponding brain tissues. Northern-blot analysis of a variety of tissues indicated that both 80K and MARCKS have similar patterns of expression. Most components of signal-transduction pathways are present in multiple molecular isoforms as members of a gene family. In contrast, the findings presented in this study indicate that rodent 80K and bovine and human MARCKS are not distinct members of a gene family, but represent the equivalent substrates in different species.

The expression of 80K/MARCKS, a major substrate of protein kinase C (PKC), is down-regulated through both PKC-dependent and -independent pathways. Effects of bombesin, platelet-derived growth factor, and cAMP

We have examined the regulation of expression of 80K/MARCKS, a major and specific protein kinase C (PKC) substrate of Swiss 3T3 fibroblasts. Addition of bombesin (10 nM) to confluent quiescent cultures of these cells induced a dramatic and sustained down-regulation of 80-kDa mRNA and protein levels to a minimum of 5% of control within 8 and 48 h, respectively, without depletion of PKC activity. In contrast, the effect of phorbol 12,13-dibutyrate on 80K/MARCKS mRNA levels was transient, and recovery of these transcripts correlated with the loss of PKC activity. The ability of bombesin to down-regulate 80K/MARCKS mRNA levels was dose-dependent (ED50 0.5 nM) and was abolished by both the specific bombesin antagonist [Leu13 psi (CH2NH),Leu14]bombesin and by prior depletion of PKC. Of a range of agents tested, platelet-derived growth factor (PDGF), but not insulin or Ca2+ ionophore, also down-regulated 80K/MARCKS mRNA to 24% of control within 5 h. Prior down-regulation of PKC abolished the effect of PDGF at a concentration of 7 ng/ml. Surprisingly, at higher doses (25 ng/ml), PDGF induced the down-regulation of 80K/MARCKS mRNA in a PKC-independent manner. Furthermore, elevation of cAMP, either through receptor-mediated mechanisms (e.g. prostaglandin E1) or by direct stimulation of adenylate cyclase (e.g. forskolin), also caused a marked dose-dependent depletion of 80K/MARCKS mRNA levels, which were further reduced by co-administration with cAMP-phosphodiesterase inhibitors. The rate of transcription of the 80K/MARCKS gene was unaltered by treatment of cells with either bombesin, PDGF, or forskolin/1-methyl-3-isobutylxanthine. These results indicate a role for both PKC-dependent and -independent pathways in growth factor-induced down-regulation of 80K/MARCKS expression, through a post-transcriptional mechanism.

Superinfection with porcine cytomegalovirus initiating transplacental infection

Four sows with circulating antibody were exposed to porcine cytomegalovirus. Virus was detected in 8 of 24 foetuses by immunofluorescence and/or virus isolation from 2 sows with low levels of antibody. In 6 of the infected foetuses, the virus was in capillary endothelium and macrophages of the lung, and was associated with interlobular oedema in 2 of these. Virus was also detected in the nasal mucosa, spleen and brain. The majority of the virus-positive foetuses were grossly normal.

Evaluation of the new Gravigard IUCD inserter

Incorporation of a flexible plastic rod into the new Gravigard plastic inserter assembly has, in our opinion, allowed for easier insertion and positioning of the device in the uterus compared with the previously available metal rod.