Characterization of Xanthomonas campestris pv. pruni strains from different hosts by pathogenicity tests and analysis of whole-cell fatty acids and whole-cell proteins

Strains of Xanthomonas campestris pv. pruni obtained from Prunus armeniaca. P. domestica, P. persica and P. salicina in different geographical areas were compared for pathogenicity, fatty acid and wholecell protein analysis. Four strains, one per each host plant, were inoculated at the same time, on the foliage of P. armeniaca, P. avium, P. persica and P. salicina cultivars . Mean content of fatty acids of X.c. pv. pruni strains were also compared with those of many strains of X.c. pv. campestris , pv. graminis , pv. hyacinthii , pv. pelargonii and pv. vasculorum. Strains showed a remarkable homogeneity in fatty acids content and whole-cell protein profiles and principal component and cluster analysis did not reveal any grouping according to original host or geographical origin. However, X.c . pv. pruni strains can be grouped apart from the other X. campestris pathovars. There appears to be no pathogenic specialization among the strains tested, however, they varied in aggressiveness to host plants and host plant in susceptibility. The most of the strains were able to cross-infect species other that from where they were originally isolated, although, P. avium did not show any symptom of disease. P. persica cv. Sentry and P. salicina cv. Globe Sun, recently licensed as resistant to X.c. pv. pruni. were infected, although to a lesser extent, by some strains.     

Three-dimensional cancer cell culture in high-yield multiscale scaffolds by shear spinning

Polymeric scaffolds comprising two size scales of microfibers and submicron fibers can better support three-dimensional (3D) cell growth in tissue engineering, making them an important class of healthcare material. However, a major manufacturing barrier hampers their translation into wider practical use: scalability. Traditional production of two-scale scaffolds by electrospinning is slow and costly. For day-to-day cell cultures, the scaffolds need to be affordable, made in high yield to drive down cost. Combining expertise from academia and industry from the United Kingdom and United States, this study uses a new series of high-yield, low-cost scaffolds made by shear spinning for tissue engineering. The scaffolds comprise interwoven submicron fibers and microfibers throughout as observed under scanning electron microscopy and demonstrate good capability to support cell culturing for tumor modeling. Three model human cancer cell lines (HEK293, A549 and MCF-7) with stable expression of GFP were cultured in the scaffolds and found to exhibit efficient cell attachment and sustained 3D growth and proliferation for 30 days. Cryosection and multiphoton fluorescence microscopy confirmed the formation of compact 3D cell clusters throughout the scaffolds. In addition, comparative growth curves of 2D and 3D cultures show significant cell-type-dependent differences. This work applies high-yield shear-spun scaffolds in mammalian tissue engineering and brings practical, affordable applications of multiscale scaffolds closer to reality. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2750, 2019.     

Centrosome defects cause microcephaly by activating the 53BP1‐USP28‐TP53 mitotic surveillance pathway

Mutations in centrosome genes deplete neural progenitor cells (NPCs) during brain development, causing microcephaly. While NPC attrition is linked to TP53‐mediated cell death in several microcephaly models, how TP53 is activated remains unclear. In cultured cells, mitotic delays resulting from centrosome loss prevent the growth of unfit daughter cells by activating a pathway involving 53BP1, USP28, and TP53, termed the mitotic surveillance pathway. Whether this pathway is active in the developing brain is unknown. Here, we show that the depletion of centrosome proteins in NPCs prolongs mitosis and increases TP53‐mediated apoptosis. Cell death after a delayed mitosis was rescued by inactivation of the mitotic surveillance pathway. Moreover, 53BP1 or USP28 deletion restored NPC proliferation and brain size without correcting the upstream centrosome defects or extended mitosis. By contrast, microcephaly caused by the loss of the non‐centrosomal protein SMC5 is also TP53‐dependent but is not rescued by loss of 53BP1 or USP28. Thus, we propose that mutations in centrosome genes cause microcephaly by delaying mitosis and pathologically activating the mitotic surveillance pathway in the developing brain.     

Healthcare without borders: A cross-sectional study of immigrant and nonimmigrant children admitted to a large public sector hospital in the Gauteng Province of South Africa

BackgroundHuman migration is a worldwide phenomenon that receives considerable attention from the media and healthcare authorities alike. A significant proportion of children seen at public sector health facilities in South Africa (SA) are immigrants, and gaps have previously been noted in their healthcare provision.The objective of the study was to describe the characteristics and differences between the immigrant and SA children admitted to Kalafong Provincial Tertiary Hospital (KPTH), a large public sector hospital in the urban Gauteng Province of SA.Methods and findingsA cross-sectional study was conducted over a 4-month period during 2016 to 2017. Information was obtained through a structured questionnaire and health record review. The enrolled study participants included 508 children divided into 2 groups, namely 271 general paediatric patients and 237 neonates. Twenty-five percent of children in the neonatal group and 22.5% in the general paediatric group were immigrants. The parents/caregivers of the immigrant group had a lower educational level (p < 0.0001 neonatal and paediatric), lower income (neonatal p < 0.001; paediatric p = 0.024), difficulty communicating in English (p < 0.001 neonatal and paediatric), and were more likely residing in informal settlements (neonatal p = 0.001; paediatric p = 0.007) compared to the SA group. In the neonatal group, there was no difference in the number of antenatal care (ANC) visits, type of delivery, gestational age, and birth weight. In the general paediatric group, there was no difference in immunisation and vitamin A supplementation coverage, but when comparing growth, the immigrant group had more malnutrition compared to the SA group (p = 0.029 for wasting). There was no difference in the prevalence of maternal human immunodeficiency virus (HIV) infection, with equally good prevention of mother-to-child transmission (PMTCT) coverage. There was also no difference in reported difficulties by immigrants in terms of access to healthcare (neonatal p = 0.379; paediatric p = 0.246), although a large proportion (10%) of the neonates of immigrant mothers were born outside a medical facility.ConclusionsAlthough there were health-related differences between immigrant and SA children accessing in-hospital care, these were fewer than expected. Differences were found in parental educational level and socioeconomic factors, but these did not significantly affect ANC attendance, delivery outcomes, immunisation coverage, HIV prevalence, or PMTCT coverage. The immigrant population should be viewed as a high-risk group, with potential problems including suboptimal child growth. Health workers should advocate for all children in the community they are serving and promote tolerance, respect, and equal healthcare access.     

COMPARISON OF GROWTH CHARACTERISTICS OF EXPERIMENTAL TUMOURS AND DERIVED CELL CULTURES

Cells from seven different rat tumours and a mouse sarcoma have been transplanted in syngeneic animals and were cultured in vitro. Tumours produced by inoculation of cultured cells in animals have been compared with the primary tumours. For the transplanted tumours, volume doubling times, T_d, have been compared with doubling times, T_d(cult), of cell numbers in cultures. Volume doubling times of the transplanted tumours generally decrease with increasing volume. At volumes of about 0.5 cm³, T_d values range from 2.2 days to 10 days, while T_d(cult) values ranged from 11 to 24 hr. A systematic correlation between T_d and T_d(cult) could not be established. During sequential transplantation of the tumours for many generations, as well as during continuous propagation of derived cell cultures, significant changes occurred which resulted in a decrease in the expression of differentiation characteristics in tumours.     

Distribution of IgM- and IgG-containing cells during the primary immune response in the rat spleen

Summary The morphology and localisation of IgM- and IgG-containing cells in the spleen of rats immunized with sheep red-blood cells (SRBC) were studied by combining immunohistochemical reactions with routine histological and histochemical methods. It was shown that IgM cells occur only in the outer periarteriolar lymphocyte sheath (PALS), whereas IgG cells are present throughout the whole PALS. It has been concluded that these cell types have different routes of migration. Both IgM- and IgG-containing cells were found in the germinal center in close relation with the extracellular immune complexes. The significance of this localisation is discussed.