Effects of the ecto-ATPase apyrase on microglial ramification and surveillance reflect cell depolarization, not ATP depletion

Microglia, the brain’s innate immune cells, have highly motile processes which constantly survey the brain to detect infection, remove dying cells, and prune synapses during brain development. ATP released by tissue damage is known to attract microglial processes, but it is controversial whether an ambient level of ATP is needed to promote constant microglial surveillance in the normal brain. Applying the ATPase apyrase, an enzyme which hydrolyzes ATP and ADP, reduces microglial process ramification and surveillance, suggesting that ambient ATP/ADP maintains microglial surveillance. However, attempting to raise the level of ATP/ADP by blocking the endogenous ecto-ATPase (termed NTPDase1/CD39), which also hydrolyzes ATP/ADP, does not affect the cells’ ramification or surveillance, nor their membrane currents, which respond to even small rises of extracellular [ATP] or [ADP] with the activation of K+ channels. This indicates a lack of detectable ambient ATP/ADP and ecto-ATPase activity, contradicting the results with apyrase. We resolve this contradiction by demonstrating that contamination of commercially available apyrase by a high K+ concentration reduces ramification and surveillance by depolarizing microglia. Exposure to the same K+ concentration (without apyrase added) reduced ramification and surveillance as with apyrase. Dialysis of apyrase to remove K+ retained its ATP-hydrolyzing activity but abolished the microglial depolarization and decrease of ramification produced by the undialyzed enzyme. Thus, applying apyrase affects microglia by an action independent of ATP, and no ambient purinergic signaling is required to maintain microglial ramification and surveillance. These results also have implications for hundreds of prior studies that employed apyrase to hydrolyze ATP/ADP.</p

Fig rust caused by Phakopsora nishidana in South Africa

Fig rust, caused by Cerotelium fici, was first recorded in South Africa in 1927. Recent observations have revealed high incidence of rust and untimely defoliation of fig trees (Ficus carica) in residential gardens and commercial orchards. Using phylogenetic analysis, the causal organism of a fig rust isolate (PREM63073) collected in 2020 was confirmed as Phakopsora nishidana. Inoculation and microscope studies showed that mulberry plants were immune to P. nishidana isolate PREM63073. Infection of fig leaves occurred through stomata on the abaxial leaf surfaces. Very long germ tubes were observed for P. nishidana, often with no clear contact with the leaf surfaces and an apparent lack of directional growth towards stomata. Inoculated plants from 15 fig cultivars varied in their severity of leaf infection, whereas fruit of the cultivar Kadota developed reddish-brown blemishes without sporulation. Currently, C. fici and P. nishidana are recognised as occurring on F. carica in South Africa. This suggests a need to resolve the worldwide distribution and identity of the rust species involved

Elektroforetiese skeidings van die proteïne in die perivitellienvog van die basommatophora [Mollusca] as taksonomiese hulpmiddel

DSc, North-West University, Potchefstroom CampusElectrophoretic separation of the proteins of the perivitelline fluid of the Basommatophora as a taxonomic criterion was undertaken on 13 species and sub= species of the genera Bu_Zinue and BiomphaZaria. The value of zone electrophoresis in providing insight into problems of molluscan systematics was investigated. The influence of various natural and physiological factors such as food, snail age, the age of the eggs, interbreeding, different populations and rearing temperature on the proteins in the perivitelline fluid of B. (B.) tropiaus, was studied. This information was analized statistically. It appeared that of 'all the factors tested only the age of the eggs, snail age and extreme rearing temperatures had any notable effects on the proteins in the perivitelline fluid. New method for collecting the perivitelline fluid and for applying the sample, are described. The variations resulting from the method of collecting, application and various other experimental procedures and the ways to eliminate these are discussed. It was concluded that electrophoretic separations of the perivitelline fluid provides valuable criteria for the identification of the snail species used in this study. It was found that electrophoretic separations are sensitive indicators of differences at the population, subspecies and species level. It was, however, disappointing that this technique failed to disclose any characteristics in the electrophoretograms which could be correlated with susceptibility for infestation with schistosomes.Doctora

&lt;p&gt;&lt;strong&gt;A review of jumping plant lice of the genus &lt;em&gt;Ctenarytaina&lt;/em&gt; (Hemiptera, Psylloidea, Aphalaridae) associated with &lt;em&gt;Syzygium&lt;/em&gt; (Myrtaceae)&lt;/strong&gt;&lt;/p&gt;

Twelve Ctenarytaina species with confirmed or suspected associations with Syzygium are revised. The following six new species are diagnosed, described and illustrated: Ctenarytaina baliota Burckhardt sp. nov. (from Malaysia: Sabah), C. daleae Burckhardt sp. nov. (Malaysia: Sabah), C. loebli Burckhardt sp. nov. (Malaysia: Sabah), C. melanota Burckhardt sp. nov. (South Africa), C. picea Burckhardt sp. nov. (Thailand) and C. taylori Burckhardt sp. nov. (Malaysia: Sabah). One new generic synonym is proposed (Ctenarytaina = Eurhinocola syn. nov.) as are two new combinations: Ctenarytaina aurata (Li), comb. nov. from Neophyllura, and Ctenarytaina gravelyi (Crawford), comb. nov. from Eurhinocola.  A key is provided to adults and, as far as known, to the fifth instar immatures. Two African species (Ctenarytaina fomenae Tamesse and C. melanota sp. nov.) induce witches’ broom on their hosts. Confirmed host plants of Ctenarytaina species are from Syzygium (6 spp.), Eucalyptus (5 spp.) and other Myrtaceae, as well as from one genus in each of the families Onagraceae, Rutaceae and Theaceae. More than two thirds of the species with confirmed hosts are monophagous, the others are narrowly oligophagous. About one fifth of the described Ctenarytaina species have adventive populations outside their natural range. Key words: adventive, distribution, host plant, Phytoplasma, Spondyliaspidinae, Sternorrhyncha, taxonomy, witches’ broom</jats:p

Machine learning risk prediction of mortality for patients undergoing surgery with perioperative SARS-CoV-2: the COVIDSurg mortality score

To support the global restart of elective surgery, data from an international prospective cohort study of 8492 patients (69 countries) was analysed using artificial intelligence (machine learning techniques) to develop a predictive score for mortality in surgical patients with SARS-CoV-2. We found that patient rather than operation factors were the best predictors and used these to create the COVIDsurg Mortality Score (https://covidsurgrisk.app). Our data demonstrates that it is safe to restart a wide range of surgical services for selected patients.</jats:p