Extraction of DNA from exfoliative cytology specimens and its suitability for analysis by the polymerase chain reaction

The extraction of DNA from archival exfoliative cytology samples would allow the molecular biological analysis of this readily available material using the polymerase chain reaction (PCR). We have quantitatively and qualitatively studied the extraction of DNA from a variety of cytological preparations. For both fresh and archival cervical smears, overnight incubation with proteinase K produces high yields of high molecular weight DNA, but simply boiling the samples produces DNA suitable for PCR amplification of a single copy gene. Increasing the proteinase K incubation to several days allows the extraction of DNA from fixed and stained archival cytology slides from a variety of sites. The extracted DNA was again suitable for PCR analysis. Fresh and archival cytological material can be utilized for molecular biological study of disease processes using PCR. Archival cytological material is probably the best source of DNA and RNA after stored frozen tissue.     

Song mimicry of Black-bellied Firefinch Lagonosticta rara and other finches by the brood-parasitic Cameroon Indigobird Vidua camerunensis in West Africa

Brood-parasitic finches Vidua spp. mimic songs of their foster species, with most Vidua species both mimicking songs and parasitizing nests of a single estrildid finch species. We describe a behavioural radiation in the Cameroon Indigobird Vidua camerunensis . Local populations are polymorphic in behaviour, each male mimicking songs of a single species, with certain males mimicking songs of one species and other males mimicking songs of another host species. The species most often mimicked in song are Black-bellied Firefinch Lagonosticta rara and African Firefinch L. rubricata ; other species mimicked in song are Brown Twinspot Clytospiza monteiri and Dybowski's Twinspot Euschistospiza dybowskii . Indigobirds in the different mimicry song populations do not differ morphologically in plumage colour or size. The lack of morphological differences between male indigobirds with different mimicry songs is consistent with a recent behavioural radiation through host shifts, perhaps facilitated by environmental change associated with prehistoric cultivation of grain. The mimicry song populations of indigobirds, behaviourally imprinted upon different host species, support the idea of a process of speciation driven by a shift to new host species.     

A new species of firefinch Lagonosticta from northern Nigeria and its association with the Jos Plateau Indigobird Vidua maryae

A firefinch of the Jos Plateau, northern Nigeria, is described as a new species, Rock Fire-finch Lagonosticta sanguinodorsalis. This firefinch has distinctive songs and a distinctive habitat—bushy and grassy rocky outcrops on the plateau and inselbergs to the north and east. It has a blue-grey bill, red back in the male and reddish brown back in the female and juvenile and broad primaries in both the adult and juvenile. It appears most closely related to the Mali Firefinch Lagonosticta virata and the Chad Firefinch Lagonosticta umbrinodorsalis. Its songs are mimicked by the brood-parasitic Jos Plateau Indigobird Vidua maryae , which occurs within the range of the firefinch and whose songs led to the discovery of the firefinch. The songs of the firefinch, the song mimicry of the indigobird and the apparent continuity of song mimicry across 27 years indicate a unique association of this distinct pair of species.     

Relationship between clinical signs and postmortem test status in cattle experimentally infected with the bovine spongiform encephalopathy agent

Background  

Various clinical protocols have been developed to aid in the clinical diagnosis of classical bovine spongiform encephalopathy (BSE), which is confirmed by postmortem examinations based on vacuolation and accumulation of disease-associated prion protein (PrP^d) in the brain. The present study investigated the occurrence and progression of sixty selected clinical signs and behaviour combinations in 513 experimentally exposed cattle subsequently categorised postmortem as confirmed or unconfirmed BSE cases. Appropriate undosed or saline inoculated controls were examined similarly and the data analysed to explore the possible occurrence of BSE-specific clinical expression in animals unconfirmed by postmortem examinations.     

Some Effects of Sodium Chloride on Germination and Seedling Growth of Sugar Beet

Soaking sugar-beet seed in 1.0 M sodium chloride solution killed6 per cent of the seeds but the remainder germinated when transferredto more dilute (< 0.28 M) solutions. Small differences inthe concentration of dilute sodium chloride did not change thenumber of seeds which germinated but greatly affected wateruptake and seedling growth. For example, after 10 days at 15?C, radical length decreased almost linearly from 50 to 5 mmwhen the concentration increased from 0 to 0.2 M. Presoakingseed in water increased the concentration tolerated withoutreduction in growth. Advancing seed (presoaking followed byairdrying) increased seedling yield by 70 per cent by decreasingthe time taken to emerge, increasing the number of seeds whichgerminated and eliminating the detrimental effects of smallamounts of sodium chloride. Advancing seed also marginally reducedthe variation in seedling yield in laboratory and controlledenvironment experiments. To minimize the risk of killing seedsor decreasing seedling growth it seems that no more than therecommended quantity (377 kg ha^–1) of sodium chlorideshould be applied to sugar-beet crops.     

Defining a minimal cell: essentiality of small ORFs and ncRNAs in a genome-reduced bacterium

Identifying all essential genomic components is critical for the assembly of minimal artificial life. In the genome-reduced bacterium Mycoplasma pneumoniae, we found that small ORFs (smORFs; < 100 residues), accounting for 10% of all ORFs, are the most frequently essential genomic components (53%), followed by conventional ORFs (49%). Essentiality of smORFs may be explained by their function as members of protein and/or DNA/RNA complexes. In larger proteins, essentiality applied to individual domains and not entire proteins, a notion we could confirm by expression of truncated domains. The fraction of essential non-coding RNAs (ncRNAs) non-overlapping with essential genes is 5% higher than of non-transcribed regions (0.9%), pointing to the important functions of the former. We found that the minimal essential genome is comprised of 33% (269,410 bp) of the M. pneumoniae genome. Our data highlight an unexpected hidden layer of smORFs with essential functions, as well as non-coding regions, thus changing the focus when aiming to define the minimal essential genome.     

Acute pancreatitis

Pain, and nausea and vomiting are the two cardinal symptoms of acute pancreatitis. There are variations in the combinations of symptoms that appear in patients who have acute pancreatitis, but in most cases the combination fits one or another of five classifications. Blood amylase and urinary diastase determinations are valuable aids in the diagnosis of acute pancreatitis. These findings must be correlated with the stage of the disease. As the disease may be treated successfully (by means outlined) without surgical intervention, clinical diagnosis is important. Cholecystograms after an attack of acute pancreatitis, although advisable, should not be made too soon after subsidence, because of the danger of exacerbation.