Small rodent population synchrony in western Sweden. Effects of landscape structure.

Small rodents were captured in two regions in western Sweden. One represents an agricultural landscape were captures were made in 19 small habitat islands and in two small forests. The other represents a forest region were captures were made in four sites in a continuous forest. The captures were made for seven years. There were no clear indications of cyclicity. Within both regions, wood mice captures were in synchrony among sites. For bank voles, this was only true in the forest region and for field voles in the agricultural region. Captures of field voles were too few for analysis in the forest region. Among species, captures were not synchronous in the agricultural region but captures of wood mice and bank voles were synchronous in the forest region. These results suggest a role of landscape structure for the population dynamics of these species, rather than differences in predator function

Temperature, genetic and hydroperiod effects on metamorphosis of brown frogs Rana arvalis and R-temporaria in the field

Time for metamorphosis and metamorph size of moor frogs Rana arvalis and common frogs R. temporaria were measured in 22 ponds for 18 years. Environmental data in these ponds were also measured. Metamorphosis of the frogs took place from the beginning of June to the beginning of August. When both species were found in one pond, the common frogs metamorphosed up to 20 days earlier than the moor frogs. Most variation in time for metamorphosis, among ponds and years, is explained by temperature effects, but a causal relationship was not established. Within a pond, metamorphosis was later in cold summers than in warm summers. Size at metamorphosis was affected by tadpole density; at high densities metamorphs were smaller. Size at metamorphosis was not related to time for metamorphosis. There was an effect of pond drying; if ponds were about to dry up, metamorphosis was accelerated by about 2.4 days. Tadpoles from ponds with a late metamorphosis in the field had tadpoles that metamorphosed early in a common garden experiment, suggesting counter gradient selection.Time for metamorphosis and metamorph size of moor frogs Rana arvalis and common frogs R. temporaria were measured in 22 ponds for 18 years. Environmental data in these ponds were also measured. Metamorphosis of the frogs took place from the beginning of June to the beginning of August. When both species were found in one pond, the common frogs metamorphosed up to 20 days earlier than the moor frogs. Most variation in time for metamorphosis, among ponds and years, is explained by temperature effects, but a causal relationship was not established. Within a pond, metamorphosis was later in cold summers than in warm summers. Size at metamorphosis was affected by tadpole density; at high densities metamorphs were smaller. Size at metamorphosis was not related to time for metamorphosis. There was an effect of pond drying; if ponds were about to dry up, metamorphosis was accelerated by about 2.4 days. Tadpoles from ponds with a late metamorphosis in the field had tadpoles that metamorphosed early in a common garden experiment, suggesting counter gradient selection.Time for metamorphosis and metamorph size of moor frogs Rana arvalis and common frogs R. temporaria were measured in 22 ponds for 18 years. Environmental data in these ponds were also measured. Metamorphosis of the frogs took place from the beginning of June to the beginning of August. When both species were found in one pond, the common frogs metamorphosed up to 20 days earlier than the moor frogs. Most variation in time for metamorphosis, among ponds and years, is explained by temperature effects, but a causal relationship was not established. Within a pond, metamorphosis was later in cold summers than in warm summers. Size at metamorphosis was affected by tadpole density; at high densities metamorphs were smaller. Size at metamorphosis was not related to time for metamorphosis. There was an effect of pond drying; if ponds were about to dry up, metamorphosis was accelerated by about 2.4 days. Tadpoles from ponds with a late metamorphosis in the field had tadpoles that metamorphosed early in a common garden experiment, suggesting counter gradient selection.A correction to this article is found in Journal of Zoology (2003)260(2)p.217-21

Plastic response to pond drying in tadpoles Rana temporaria: tests of cost models

Tadpoles from two types of ponds, temporary and permanent, were raised in a common garden experiment. There was no clear effect of pond type on development rate (time for metamorphosis). From each sibship, one group was raised under a constant water regime (deep tanks) and one was subject to simulated pond drying (shallow tanks). The tadpoles exhibited a plastic response to pond drying: they metamorphosed earlier in the shallow than in the deep tanks. There was no interaction between pond type and tank type; that is, there was no indication of microevolution on plasticity per se. Sibships with a high degree of plasticity (much earlier metamorphosis in shallow than in deep tanks) had a larger size reduction from deep to shallow tanks, suggesting a trade-off between time and size. This may be considered an allocation cost sensu Tollrian and Harvell (1999). However, tadpoles from early sibships that were plastic were of a similar size to those from early sibships that were not plastic (those that were early in the deep tank as well). This suggests that there was no production cost sensu DeWitt et at (1998). Sibships with high plasticity had tadpoles that grew large in the deep tank and developed slowly (late metamorphosis) in this tank. This suggests that plastic tadpoles were those that, because of their size, most readily could afford any costs associated with plasticity and those that, because of slow development, most easily could increase development rate. The relation to size is the opposite to that predicted if the capacity for plasticity is associated with cost (plasticity cost sensu Tollrian and Harvell, 1999; maintenance cost sensu De Witt et al, 1998)

Communal spawning in the common frog Rana temporaria - Egg temperature and predation consequences

Females of the common frog, Rana temporaria, spawn synchronously at communal breeding sites, forming a communal egg mass of individual spawn clumps. A total of four spawning sites were studied. In the centre of the communal egg mass, daily maximum temperature was higher and minimum temperature lower than further out. Spawn clumps in the centre of the communal egg mass developed faster than single spawn clumps. In the centre of the egg masses, some spawn clumps suffered almost total egg mortality. This was probably the consequence of a cold spell with sub-zero temperatures in combination with a tendency for low minimum temperatures in the centre. In a laboratory study, worm leeches, Erpobdella spp., fed readily on eggs of common frog, while horse leeches, Haemopis sanguisuga, hardly ate any eggs. At the spawning sites, most worm leeches were found in single spawn clumps, far from the communal egg mass. Females which spawned late, when most of the spawning was over, preferred to spawn in the centre of the communal egg mass. This suggests that there is a net advantage for eggs in spawn clumps laid in the centre

Staden genom maten : en kultursociologisk textanalys av Sydsvenskans restaurangrecensioner 1995, 2005 och 2015

Mat, kockarna som lagar den och restaurangerna som serverar den har sedan början av 2000-talet upptagit mer av utrymmet i flertalet medier, inte minst tv-medier. Matens fält har blivit ett populärkulturellt fenomen värt att undersökas vetenskapligt. Mycket av den forskningen på ämnet som idag görs är fokuserade på internets användargenererade recensioner. Sydsvenskans recensioner signerade Bong har sedan 1995 publicerats regelbundet och en kultursociologisk textsanalys görs i uppsatsen för att se hur dominerande samhällsströmningar och ideologier verkar och förstärks genom recensionerna. Blottläggandet av vad som sägs bortom texten är viktigt för att kunna se vad journalistiken verkligen säger, inte bara vad den verkar säga. Teoretiskt ramverk är Bourdieus begreppsvärld av fältteori och symboliskt kapital men även postmodernistiska teorier om populärkultur används. Analysen visar att det kulturella mat- och restaurangfältet har förändrats från ett statiskt, traditionsbundet fält djupt styrt av modernismens klassamhälle till en postmodern hyperrealitet där maten fungerar som underhållning

Epigenetic silencing and deletion of the BRCA1 gene in sporadic breast cancer

INTRODUCTION: BRCA1 or BRCA2 germline mutations increase the risk of developing breast cancer. Tumour cells from germline mutation carriers have frequently lost the wild-type allele. This is predicted to result in genomic instability where cell survival depends upon dysfunctional checkpoint mechanisms. Tumorigenic potential could then be acquired through further genomic alterations. Surprisingly, somatic BRCA mutations are not found in sporadic breast tumours. BRCA1 methylation has been shown to occur in sporadic breast tumours and to be associated with reduced gene expression. We examined the frequency of BRCA1 methylation in 143 primary sporadic breast tumours along with BRCA1 copy number alterations and tumour phenotype. METHODS: Primary sporadic breast tumours were analysed for BRCA1α promoter methylation by methylation specific PCR and for allelic imbalance (AI) at BRCA1 and BRCA2 loci by microsatellite analysis and TP53 (also known as p53) mutations by constant denaturing gel electrophoresis. The BRCA1 methylated tumours were analysed for BRCA1 copy alterations by fluorescence in situ hybridisation and BRCA1 expression by immunostaining. RESULTS: BRCA1 methylation was found in 13/143 (9.1%) sporadic breast tumours. The BRCA1 methylated tumours were significantly associated with estrogen receptor (ER) negativity (P = 0.0475) and displayed a trend for BRCA1 AI (P = 0.0731) as well as young-age at diagnosis (≤ 55; P = 0.0898). BRCA1 methylation was not associated with BRCA2 AI (P = 0.5420), although a significant association was found between BRCA1 AI and BRCA2 AI (P < 0.0001). Absent/markedly reduced BRCA1 expression was observed in 9/13 BRCA1 methylated tumours, most of which had BRCA1 deletion. An elevated TP53 mutation frequency was found among BRCA1 methylated tumours (38.5%) compared with non-methylated tumours (17.2%). The BRCA1 methylated tumours were mainly of tumour grade 3 (7/13) and infiltrating ductal type (12/13). Only one methylated tumour was of grade 1. CONCLUSION: BRCA1 methylation is frequent in primary sporadic breast tumours. We found an indication for BRCA1 methylation to be associated with AI at the BRCA1 locus. Almost all BRCA1 methylated tumours with absent/markedly reduced BRCA1 expression (8/9) displayed BRCA1 deletion. Thus, epigenetic silencing and deletion of the BRCA1 gene might serve as Knudson's two 'hits' in sporadic breast tumorigenesis. We observed phenotypic similarities between BRCA1 methylated and familial BRCA1 tumours, based on BRCA1 deletion, TP53 mutations, ER status, young age at diagnosis and tumour grade

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p