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Abstract Background Data on the genus Sarcocystis in insectivores are limited. The Asian gray shrew Crocidura attenuata is one of the most common species of the insectivore family Soricidae in South Asia and Southeast Asia. To our knowledge, species of Sarcocystis have never been recorded previously in this host. Methods Tissues were obtained from 42 Asian gray shrews caught in 2017 and 2018 in China. Sarcocysts were observed using light microscopy (LM) and transmission electron microscopy (TEM). To describe the parasite life cycle, muscle tissues of the host infected with sarcocysts were force-fed to two beauty rat snakes Elaphe taeniura. Individual sarcocysts from different Asian gray shrews, and oocysts/sporocysts isolated from the small intestines and feces of the experimental snakes, were selected for DNA extraction, and seven genetic markers, namely, two nuclear loci [18S ribosomal DNA (18S rDNA) and internal transcribed spacer region 1 (ITS1)], three mitochondrial genes [cytochrome oxidase subunit 1 (cox1), cox3 and cytochrome b], and two apicoplast genes (RNA polymerase beta subunit and caseinolytic protease C), were amplified, sequenced and analyzed. Results Sarcocysts were found in 17 of the 42 (40.5%) Asian gray shrews. Under LM, the microscopic sarcocysts showed saw- or tooth-like protrusions measuring 3.3–4.5 μm. Ultrastructurally, the sarcocyst wall contained numerous lancet- or leaf-like villous protrusions, similar to those described for type 9h of the common cyst wall classification. The experimental beauty rat snakes shed oocysts/sporocysts measuring 11.9–16.7 × 9.2–10.6 μm with a prepatent period of 10–11 days. Comparison of the newly obtained sequences with those previously deposited in GenBank revealed that those of 18S rDNA and cox1 were most similar to those of Sarcocystis scandentiborneensis recorded in the tree shrews Tupaia minor and Tupaiatana (i.e., 97.6–98.3% and 100% identity, respectively). Phylogenetic analysis based on 18S rDNA or ITS1 sequences placed this parasite close to Sarcocystis spp. that utilize small animals as intermediate hosts and snakes as the known or presumed definitive host. On the basis of morphological and molecular characteristics and host specificity, the parasite was proposed as a new species, named Sarcocystis attenuati. Conclusions Sarcocysts were recorded in Asian gray shrews, to our knowledge for the first time. Based on morphological and molecular characterization, a new species of parasite is proposed: Sarcocystisattenuati. According to the LM and TEM results, S. attenuati sarcocysts are distinct from those of Sarcocystis spp. in other insectivores and those of S. scandentiborneensis in tree shrews. The 18S rDNA or cox1 sequences of Sarcocystis attenuati shared high similarity with those of Sarcocystisscandentiborneensis, Sarcocystis zuoi, Sarcocystis cf. zuoi in the Malayan field rat, and Sarcocystis sp. in the greater white-toothed shrew. Therefore, we suggest that more research on the relationships of these closely related taxa should be undertaken in the future. Graphical abstract

Abstract Background The prediction of clinical behaviour of breast ductal carcinoma in situ (DCIS) and its progression to invasive disease remains a challenge. Alterations of DNA damage repair mechanisms are associated with invasive breast cancer (BC). This study aims to assess the role of base excision repair (BER) DNA Polymerase Beta (POLβ) in DCIS. Methods A cohort of DCIS comprising pure DCIS (n = 776) and DCIS coexisting with invasive BC (n = 239) were prepared as tissue microarrays. POLβ protein expression was assessed using immunohistochemistry and correlated with clinicopathological parameters and patient outcome. Preclinically, we investigated the impact of POLβ depletion on stem cell markers in representative DCIS cell line models. Results Reduced POLβ expression was associated with aggressive DCIS features including high nuclear grade, comedo necrosis, larger tumour size, hormonal receptor negativity, HER2 overexpression and high Ki67 index. Combined low nuclear/low cytoplasmic POLβ expression showed the strongest association with the features’ characteristics of aggressive behaviour. There was a gradual reduction in the POLβ expression from normal breast tissue, to DCIS, with the lowest expression observed in the invasive BC. Low POLβ expression was an independent predictor of recurrence in DCIS patients treated with breast conserving surgery (BCS). POLβ knockdown was associated with a significant increase in cell stemness markers including SOX2, NANOG and OCT4 levels in MCF10-DCIS cell lines. Conclusion Loss of POLβ in DCIS is associated with aggressive behaviour and it can predict recurrence. POLβ expression in DCIS provides an additional feature for patients’ risk stratification for personalised therapy.

Trypanosomatids are a group of primitive unicellular eukaryotes that can cause diseases in plants, insects, animals, and humans. Kinetoplast genome integrity is key to trypanosomatid cell survival and viability. Kinetoplast DNA (kDNA) is usually under attack by reactive oxygen and nitric species (ROS and RNS), damaging the DNA, and the cells must remove and repair those oxidatively generated lesions in order to survive and proliferate. Base excision repair (BER) is a well-conserved pathway for DNA repair after base damage, single-base loss, and single-strand breaks, which can arise from ROS, RSN, environmental genotoxic agents, and UV irradiation. A powerful BER system has been described in the T. cruzi kinetoplast and it is mainly carried out by DNA polymerase β (pol β) and DNA polymerase β-PAK (pol β-PAK), which are kinetoplast-located in T. cruzi as well as in other trypanosomatids. Both pol β and pol β-PAK belong to the X-family of DNA polymerases (pol X family), perform BER in trypanosomatids, and display intrinsic 5-deoxyribose phosphate (dRP) lyase and DNA polymerase activities. However, only Pol β-PAK is able to carry out trans-lesion synthesis (TLS) across 8oxoG lesions. T. cruzi cells overexpressing pol β are more resistant to ROS and are also more efficient to repair 8oxoG compared to control cells. Pol β seems to play a role in kDNA replication, since it associates with kinetoplast antipodal sites in those development stages in trypanosomatids which are competent for cell replication. ROS treatment of cells induces the overexpression of pol β, indicating that plays a role in kDNA repair. In this review, we will summarize the main features of trypanosomatid minicircle kDNA replication and the biochemical characteristics of pol β-like enzymes and their involvement in BER and kDNA replication. We also summarize key structural features of trypanosomatid pol β compared to their mammalian (human) counterpart.

: A series of novel pyrazolo[1,5-a][1,3,5]triazine and pyrazolo[5,1-c][1,2,4]triazine, were synthesized from the 5-aminopyrazoles 3, which was previously prepared and considered a starting precursor for synthesizing many promising bioactive compounds. Thus, all the prepared compounds were evaluated as antimicrobial agents. Also, the minimum inhibitory concentration (MIC) for the most potent compounds was measured. Moreover, docking studies were performed using the newly prepared compounds to evaluate their affinity to different bacterial target proteins with varying modes of action involving cell wall inhibition, protein and nucleic acid synthesis, and antimetabolites. Some of the prepared compounds revealed potent activity towards some of the bacterial and fungal strains used. After molecular docking study validation, it seemed that the synthetic compound mode of action was through RNA synthesis inhibition, while the DNA-dependant RNA polymerase beta subunit repC (PDB: 2AUK) was the probable protein target. The RNA polymerase inhibitory activity was measured for the most potent antimicrobial compounds with high docking scores for more evidence.

AbstractInvestigation of the prevalence and diversity of Bartonella infections in small mammals in the Qaidam Basin, western China, could provide a scientific basis for the control and prevention of Bartonella infections in humans. Accordingly, in this study, small mammals were captured using snap traps in Wulan County and Ge’ermu City, Qaidam Basin, China. Spleen and brain tissues were collected and cultured to isolate Bartonella strains. The suspected positive colonies were detected with polymerase chain reaction amplification and sequencing of gltA, ftsZ, RNA polymerase beta subunit (rpoB) and ribC genes. Among 101 small mammals, 39 were positive for Bartonella, with the infection rate of 38.61%. The infection rate in different tissues (spleens and brains) (χ2 = 0.112, P = 0.738) and gender (χ2 = 1.927, P = 0.165) of small mammals did not have statistical difference, but that in different habitats had statistical difference (χ2 = 10.361, P = 0.016). Through genetic evolution analysis, 40 Bartonella strains were identified (two different Bartonella species were detected in one small mammal), including B. grahamii (30), B. jaculi (3), B. krasnovii (3) and Candidatus B. gerbillinarum (4), which showed rodent-specific characteristics. B. grahamii was the dominant epidemic strain (accounted for 75.0%). Furthermore, phylogenetic analysis showed that B. grahamii in the Qaidam Basin, might be close to the strains isolated from Japan and China. Overall, we observed a high prevalence of Bartonella infection in small mammals in the Qaidam Basin. B. grahamii may cause human disease, and the pathogenicity of the others Bartonella species needs further study, the corresponding prevention and control measures should be taken into consideration.

Abstract BackgroundThe shape of fruit tip is critical to appearance quality and commodity value of cucumber (Cucumis sativus L.). Although diversity of cucumber fruit tip is rich, the genetic basis and molecular mechanism were poorly understood. In this study, the morphological and histological features of fruit tip were investigated to accurately evaluate the diversity in cucumber germplasm. QTLs of fruit tip were genetically mapped by using F2 and RILs populations. Candidate genes of major-effect QTLs were predicted. Results The appearance of cucumber fruit tip was generally divided into sharp, oval-round and blunt-round categories, but morphological measurement showed that the angle of fruit tip was continuously distribute in range of 99~173° and the fruit tip index (the ratio of diameter and length of tips) was in range of 1.4~3.5. Histological analysis suggested that the different structures of fruit tips were owed to the different distribution of cell number in vertical and horizontal direction, rather than difference in cell size. In total, thirty fruit tip related QTLs were identified from two mapping populations including a F2 population derived from EC1 (blunt round tip) × 8419s-1 (sharp tip) and a RILs population derived from IL52 (oval round tip) × CCMC (sharp tip). Two major-effect QTLs were detected, of which Ft4.1 was detected in both mapping population, while Ft6.1 was only identified in F2 population. The phenotypes of Ft4.1 were epistatically suppressed by dominant Ft6.1 genotype, suggesting that Ft6.1 has epistatic dominance interaction to Ft4.1. The candidate genes of Ft4.1 were predicted based on genome re-sequencing of parental lines, including CsEXT (Extension-like family protein), CsPRK (leucine-rich repeat protein kinase protein) and CsRNApase (RNA polymerase beta subunit protein), of which CsEXT and CsPRK play important functions during cell division and expansion. ConclusionsDifferent shapes of fruit tip were owed to the different frequency and orientation of cell division in tip structures. The fruit tip variation in cucumber maybe controlled by the major QTLs Ft4.1 and Ft6.1 through epistatic interaction.