A simple model for the total number of SARS-CoV-2 infections on a national level.

This study aimed to identify an appropriate simple mathematical model to fit the number of coronavirus disease 2019 (COVID-19) cases at the national level for the early portion of the pandemic, before significant public health interventions could be enacted. The total number of cases for the COVID-19 epidemic over time in 28 countries was analysed and fit to several simple rate models. The resulting model parameters were used to extrapolate projections for more recent data. While the Gompertz growth model (mean R2 = 0.998) best fit the current data, uncertainties in the eventual case limit introduced significant model errors. However, the quadratic rate model (mean R2 = 0.992) fit the current data best for 25 (89%) countries as determined by R2 values of the remaining models. Projection to the future using the simple quadratic model accurately forecast the number of future total number of cases 50% of the time up to 10 days in advance. Extrapolation to the future with the simple exponential model significantly overpredicted the total number of future cases. These results demonstrate that accurate future predictions of the case load in a given country can be made using this very simple model.

A presumptive case of cerebral babesiosis in a dog in Poland caused by a virulent Babesia canis strain.

The aim of this paper was to present the first case of cerebral canine babesiosis due to infection by Babesia canis in a dog in Poland. A 5-year-old American Staffordshire Terrier was presented with an unusual clinical manifestation of acute babesiosis that included neurological signs and pancytopenia. Despite treatment the dog died. Diagnosis was based on microscopic examination of Giemsa-stained blood smears (detection of piroplasms in red blood cells) and post mortem examination of the brain by histopathology and PCR method. The amplified segment of the Babesia 18S RNA gene was sequenced. This enabled to determine that the cause of the disease had been the strain 18S RNA-B EU622793. This is one of two B. canis strains found endemically in Poland, which reveals a greater virulence than the strain 18S RNA-A EU622792. The described case indicates that this form of canine babesiosis should be taken into account in differential diagnosis in dogs exhibiting neurological symptoms, especially in the tick activity season.

The identification of Anaplasma spp. isolated from fallow deer (Dama dama) on a free-range farm in eastern Poland.

The aim of the present study was to investigate the occurrence of Anaplasma spp. in group of 50 fallow deer (Dama dama) from free-range farm in eastern Poland and determine what species of Anaplasma could infect these animals based on PCR gene sequencing. The PCR technique revealed the presence of 16S RNA Anaplasma spp. genetic material in the blood of 7 out of 50 examined animals. The sequences of the PCR products obtained showed a 100% homology with each other and 100% homology with GU 183908 sequence of A. phagocytophilum, isolated in our earlier study from a horse with clinical form of anaplasmosis. Here, we report the first molecular evidence of Anaplasma spp. among naturally infected fallow deer in eastern Poland.

Design and chance in the self-assembly of macromolecules.

The principles of self-assembly are described for naturally occurring macromolecules and for complex assemblies formed from simple synthetic constituents. Many biological molecules owe their function and specificity to their three-dimensional folds, and, in many cases, these folds are specified entirely by the sequence of the constituent amino acids or nucleic acids, and without the requirement for additional machinery to guide the formation of the structure. Thus sequence may often be sufficient to guide the assembly process, starting from denatured components having little or no folds, to the completion state with the stable, equilibrium fold that encompasses functional activity. Self-assembly of homopolymeric structures does not necessarily preserve symmetry, and some polymeric assemblies are organized so that their chemically identical subunits pack stably in geometrically non-equivalent ways. Self-assembly can also involve scaffolds that lack structure, as seen in the multi-enzyme assembly, the degradosome. The stable self-assembly of lipids into dynamic membraneous sheets is also described, and an example is shown in which a synthetic detergent can assemble into membrane layers.

[Cyclic AMP level in the muscle tissue of cattle and the physico-chemical properties of meat]. / Poziom c-AMP w tkance miesniowej bydla a fizyczno-chemiczne wyrózniki jakosci miesa.

The purpose of this study was to determine quantitative changes of cyclic adenosine mono-phosphate (c-AMP) level in meat of slaughter bulls. Meat samples were taken from the muscle longissimus dorsi (LD) of bulls overstressed by transport, which were stunned with electricity without rest. The obtained data did not show statistical correlations between c-AMP level and pI-values but showed statistical correlations between c-AMP level and some sensory properties of beef. The highest concentration of c-AMP was detected in the muscle about 90 minutes after slaughter. Individual differences in the concentration of c-AMP in the LD were observed in 30 min. after slaughter. In this time the high c-AMP level was correlated with the colour and sensory properties of meat and bouillon.