The status of the freshwater pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> in Scotland: extent of change since 1990s,threats and management implications

All known rivers in Scotland with recent records of freshwater pearl mussels Margaritifera margaritifera were surveyed in 2013–2015 using a standard methodology. Freshwater pearl mussel populations were classed as: (i) apparently extinct in 11 rivers, (ii) not successfully recruiting in 44 rivers, and (iii) evidence of recent successful recruitment in 71 rivers. On a regional basis, a high proportion of extant populations were located in North and West Scotland. In all regions extant populations were characterised by low pearl mussel densities, with 97 of 115 extant Scottish populations defined as ‘rare’ (0.1–0.9 mussels per 1 m ²) or ‘scarce’ (1.0–9.9 mussels per 1 m ²). Only 18 Scottish rivers now hold pearl mussel populations in densities that are considered to be ‘common’ (10–19.9 mussels per 1 m ²) or ‘abundant’ (>20 mussels per 1 m ²). Based on survey evidence, the number of apparently extinct pearl mussel populations in Scottish rivers is now 73. The decline is particularly pronounced in the West Highlands and Western Isles strongholds. The key threats are: (i) pearl fishing, (ii) low host fish densities, (iii) pollution/water quality, (iv) climate change and habitat loss, (v) hydrological management/river engineering and (vi) ‘other factors’, such as non-native invasive species. Over the last 100 years this endangered species has been lost from much of its former Holarctic range. Scotland’s extant M. margaritifera populations continue to be of international importance, but their continued decline since the first national survey in 1998 is of great concern.     

A mating-type factors of Coprinus cinereus have variable numbers of specificity genes encoding two classes of homeodomain proteins

We have identified the seven genes that constitute the A43 mating-type factor of Coprinus cinereus and compare the organisation of A43 with the previously characterised A42 factor. In both, the genes that trigger clamp cell development, the so-called specificity genes, are separated into and loci by 7 kb of noncoding sequence and are flanked by homologous genes -fg and -fg. The specificity genes are known to encode two classes of dissimilar homeodomain (HD1 and HD2) proteins and have different allelic forms which show little or no cross-hybridisation. By partial sequencing we identified a divergently transcribed HD1 (a1-2) and HD2 (a2-2) gene in the A43 locus. a2-2 failed to elicit clamp cell development in three different hosts, suggesting that it is non-functional. a1-2 elicited clamp cells in an A42 host that has only an HD2 gene (a2-1) in its locus, thus demonstrating that the compatible A mating interaction is between an HD1 and an HD2 protein. The A43 locus contains three specificity genes, the divergently transcribed HD1 and HD2 genes b1-2 and b2-2 and a third HD1 gene (d1-1) that was shown by hybridisation and transformation analyses to be functionally equivalent to d1-1 in A42. An untranscribed footprint of a third A42 HD1 gene, c1-1, was detected between the A43 b2-2 and d1-1 genes by Southern hybridisation.     

Cytochrome P450 Cyp4x1 is a major P450 protein in mouse brain

A novel cytochrome P450, CYP4x1, was identified in EST databases on the basis of similarity to a conserved region in the C-helix of the CYP4A family. The human and mouse CYP4x1 cDNAs were cloned and found to encode putative cytochrome P450 proteins. Molecular modelling of CYP4x1 predicted an unusual substrate binding channel for the CYP4 family. Expression of human CYP4x1 was detected in brain by EST analysis, and in aorta by northern blotting. The mouse cDNA was used to demonstrate that the Cyp4x RNA was expressed principally in brain, and at much lower levels in liver; hepatic levels of the Cyp4x1 RNA were not affected by treatment with the inducing agents phenobarbital, dioxin, dexamethasone or ciprofibrate, nor were the levels affected in PPARalpha-/- mice. A specific antibody for Cyp4x1 was developed, and shown to detect Cyp4x1 in brain; quantitation of the Cyp4x1 protein in brain demonstrated approximately 10 ng of Cyp4x1 protein.mg(-1) microsomal protein, showing that Cyp4x1 is a major brain P450. Immunohistochemical localization of the Cyp4x1 protein in brain showed specific staining of neurons, choroids epithelial cells and vascular endothelial cells. These data suggest an important role for Cyp4x1 in the brain.     

The formin FMNL3 assembles plasma membrane protrusions that participate in cell–cell adhesion

FMNL3 is a vertebrate-specific formin protein previously shown to play a role in angiogenesis and cell migration. Here we define the cellular localization of endogenous FMNL3, the dynamics of GFP-tagged FMNL3 during cell migration, and the effects of FMNL3 suppression in mammalian culture cells. The majority of FMNL3 localizes in a punctate pattern, with >95% of these puncta being indistinguishable from the plasma membrane by fluorescence microscopy. A small number of dynamic cytoplasmic FMNL3 patches also exist, which enrich near cell–cell contact sites and fuse with the plasma membrane at these sites. These cytoplasmic puncta appear to be part of larger membranes of endocytic origin. On the plasma membrane, FMNL3 enriches particularly in filopodia and membrane ruffles and at nascent cell–cell adhesions. FMNL3-containing filopodia occur both at the cell–substratum interface and at cell–cell contacts, with the latter being 10-fold more stable. FMNL3 suppression by siRNA has two major effects: decrease in filopodia and compromised cell–cell adhesion in cells migrating as a sheet. Overall our results suggest that FMNL3 functions in assembly of actin-based protrusions that are specialized for cell–cell adhesion.     

Weight Change in Adult Life and Health Outcomes

Objective: To investigate the relationship between weight change in adult life and subsequent mortality and cancer incidence in women. Research Methods and Procedures: In 1994 to 1995, all women (age range, 42 to 81) still under general practitioner observation in the United Kingdom's Royal College of General Practitioners Oral Contraception Study (n = 12 303) were sent a health survey asking about health and lifestyle issues, including current weight and weight at age 30. The main outcome measures were 6‐year all‐cause mortality and cancer incidence among different weight change deciles. Cox regression was used to calculate hazard ratios that were adjusted for: social class at recruitment, BMI at age 30, and age group, parity, smoking status, and hormone replacement therapy status in 1995. Results: Women who had been obese at age 30 were more likely to die and significantly more likely to develop cancer in the 6 years after the health survey than non‐obese respondents. Women reporting weight gains between age 30 and 1995 were significantly less likely to die during the 6 years after the health survey than those with a stable weight, whereas those with weight loss did not fare any better than those in the stable‐weight group. Discussion: Although obesity at young age was associated with subsequent mortality and cancer incidence, weight gain over a time period of 12 to 51 years appeared to be beneficial when compared with women with stable weight over the same time period. Further research is needed to confirm or refute our findings and to allow detailed examination of potential explanations for them.     

Exploring the effect of xenon on biomembranes

We report the initial findings of 100 ns molecular dynamics simulations of the role of cellular membranes in general anaesthesia. The effect of xenon on hydrated dipalmitoylphosphatidylcholine bilayers is described. The xenon atoms were found to prefer the interfacial and central regions of the bilayer. The presence of xenon was observed to lead to a small increase in the surface area, membrane thickness, and order of the acyl chains.     

CaMKK2 facilitates Golgi-associated vesicle trafficking to sustain cancer cell proliferation

Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) regulates cell and whole-body metabolism and supports tumorigenesis. The cellular impacts of perturbing CAMKK2 expression are, however, not yet fully characterised. By knocking down CAMKK2 levels, we have identified a number of significant subcellular changes indicative of perturbations in vesicle trafficking within the endomembrane compartment. To determine how they might contribute to effects on cell proliferation, we have used proteomics to identify Gemin4 as a direct interactor, capable of binding CAMKK2 and COPI subunits. Prompted by this, we confirmed that CAMKK2 knockdown leads to concomitant and significant reductions in δ-COP protein. Using imaging, we show that CAMKK2 knockdown leads to Golgi expansion, the induction of ER stress, abortive autophagy and impaired lysosomal acidification. All are phenotypes of COPI depletion. Based on our findings, we hypothesise that CAMKK2 sustains cell proliferation in large part through effects on organelle integrity and membrane trafficking.Subject terms: Prostate cancer, Golgi     

Role of endogenous female hormones in hypoxic chemosensitivity

Tatsumi, Koichiro, Cheryl K. Pickett, Christopher R. Jacoby,John V. Weil, and Lorna G. Moore. Role of endogenous female hormones in hypoxic chemosensitivity. J. Appl.Physiol. 83(5): 1706-1710, 1997.Effective alveolar ventilation and hypoxicventilatory response (HVR) are higher in females than in males andafter endogenous or exogenous elevation of progesterone and estrogen.The contribution of normal physiological levels of ovarian hormones toresting ventilation and ventilatory control and whether their site(s) of action is central and/or peripheral are unclear.Accordingly, we examined resting ventilation, HVR, and hypercapnicventilatory responses (HCVR) before and 3 wk after ovariectomy in fivefemale cats. We also compared carotid sinus nerve (CSN) and centralnervous system translation responses to hypoxia in 6 ovariectomized and 24 intact female animals. Ovariectomy decreased serum progesterone butdid not change resting ventilation, end-tidalPCO₂, or HCVR (allP = NS). Ovariectomy reduced theHVR shape parameter A in the awake(38.9 ± 5.5 and 21.2 ± 3.0 before and after ovariectomy, respectively, P < 0.05) andanesthetized conditions. The CSN response to hypoxia was lower inovariectomized than in intact animals (shape parameterA = 22.6 ± 2.5 and 54.3 ± 3.5 in ovariectomized and intact animals, respectively,P < 0.05), but central nervous system translation of CSN activity into ventilation was similar inovariectomized and intact animals. We concluded that ovariectomy decreased ventilatory and CSN responsiveness to hypoxia, suggesting that the presence of physiological levels of ovarian hormones influences hypoxic chemosensitivity by acting primarily at peripheral sites.