Involvement of the Heat Shock Protein HtpG of Salmonella Typhimurium in Infection and Proliferation in Hosts

Salmonella Typhimurium is a common pathogen infecting the gastrointestinal tract of humans and animals, causing host gastroenteritis and typhoid fever. Heat shock protein (HtpG) as a molecular chaperone is involved in the various cellular processes of bacteria, especially under environmental stress. However, the potential association of HtpG with S. Typhimurium infection remains unknown. In this study, we clarified that HtpG could also play a role as an effector in S. Typhimurium infection. RNA-seq indicated that the flagellar assembly pathway, infection pathway, and chemotaxis pathway genes of S. Typhimurium were downregulated after the mutation of HtpG, which resulted in compromises of S. Typhimurium motility, biofilm formation, adhesion, invasion, and inflammation-inducing ability. In addition, HtpG recombinant protein was capable of promoting the proliferation of S. Typhimurium in host cells and the resultant inflammation. Collectively, our results illustrated an important role of HtpG in S. Typhimurium infection.

Understanding neutralising antibodies against SARS-CoV-2 and their implications in clinical practice

SARS-CoV-2 is a newly identified member of the coronavirus family that has caused the Coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting SARS-CoV-2 has disrupted the lives and livelihoods of millions worldwide. As of 23 August 2021, a total of 211,373,303 COVID-19 cases have been confirmed globally with a death toll of 4,424,341. A strong understanding of the infection pathway of SARS-CoV-2, and how our immune system responds to the virus is highly pertinent for guiding the development and improvement of effective treatments. In this review, we discuss the current understanding of neutralising antibodies (NAbs) and their implications in clinical practice. The aspects include the pathophysiology of the immune response, particularly humoral adaptive immunity and the roles of NAbs from B cells in infection clearance. We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting—from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.

Effects of Temperature and Wetness Duration on Infection by Coniella diplodiella, the Fungus Causing White Rot of Grape Berries

Grapevine white rot, caused by Coniella diplodiella, can severely damage berries during ripening. The effects of temperature and wetness duration on the infection severity of C. diplodiella were investigated by artificially inoculating grape berries through via infection pathways (uninjured and injured berries, and through pedicels). The effect of temperature on incubation was also studied, as was that of inoculum dose. Injured berries were affected sooner than uninjured berries, even though 100% of the berries inoculated with C. diplodiella conidia became rotted whether injured or not; infection through pedicels was less severe. On injured berries, the disease increased as the inoculum dose increased. Irrespective of the infection pathway, 1 h of wetness was sufficient to cause infection at any temperature tested (10–35 °C); with the optimal temperature being 23.8 °C. The length of incubation was shorter for injured berries than for uninjured ones, and was shorter at 25–35 °C than at lower temperatures; the shortest incubation period was 14 h for injured berries at 30 °C. Mathematical equations were developed that fit the data, with R2 = 0.93 for infection through any infection pathway, and R2 = 0.98 for incubation on injured berries, which could be used to predict infection period and, therefore, to schedule fungicide applications.

Exploring Leishmania-Host Interaction with Reactome, a Database of Biological Pathways and Processes

Leishmaniasis is a parasitic disease with a wide range of clinical manifestations. Multiple aspects of the Leishmania-host interaction, such as genetic factors and modulation of microbicidal functions in host cells, influence pathogenesis, disease severity and treatment outcome. How do scientists contend with this complexity? Here, we work towards representing detailed, contextual knowledge on Leishmania-host interactions in the Reactome pathway database to facilitate the extraction of novel mechanistic insights from existing datasets. The Reactome database uses a hierarchy of abstractions that allows for the incorporation of detailed contextual knowledge on biological processes matched to differentially expressed genes. It also includes tools for enhanced over-representation analysis that exploits this extra information. We conducted a systematic curation of published studies documenting different aspects of the Leishmania-host interaction. The 'Leishmania infection pathway' included four sub-pathways: phagocytosis, killing mechanisms, cell recruitment, and Leishmania parasite growth and survival. As proof-of-principle of the usefulness of the released pathway, we used it to analyze two previously released transcriptomic datasets of human and murine macrophages infected with Leishmania. Our results provide insights on the participation of ADORA2B signaling pathway in the modulation of IL10 and IL6 in infected macrophages. This work opens the way for other researchers to contribute to, and make use of, the Reactome database.

The Alphavirus Sindbis Infects Enteroendocrine Cells in the Midgut of Aedes aegypti

Transit of the arthropod-borne-virus (arbovirus) Sindbis (SINV) throughout adult female mosquitoes initiates with its attachment to the gut lumen, entry and amplification in midgut cells, followed by dissemination into the hemolymph. Free-mated adult females, aged day 5–7, were proffered a viremic blood suspension via sausage casings containing SINV-TaV-Green Fluorescent Protein (GFP) at a final titer of 106 PFU/mL. Midguts (MGs) from fully engorged mosquitoes were resected on days 5 and 7 post-bloodmeal, and immunolabeled using FMRFamide antibody against enteroendocrine cells (ECs) with a TX-Red secondary antibody. Following immunolabeling, the organs were investigated via laser confocal microscopy to identify the distribution of GFP and TX-Red. Infection using this reporter virus was observed as multiple GFP expression foci along the posterior midgut (PMG) epithelium and ECs were observed as TX-Red labeled cells scattered along the entire length of the MG. Our results demonstrated that SINVGFP did infect ECs, as indicated by the overlapping GFP and TX-Red channels shown as yellow in merged images. We propose that ECs may be involved in the SINV infection pathway in the mosquito MG. Due to the unique role that ECs have in the exocytosis of secretory granules from the MG and the apical-basolateral position of ECs in the PMG monolayer, we speculate that these cells may assist as a mechanism for arboviruses to cross the gut barriers. These findings suggest that MG ECs are involved in arbovirus infection of the invertebrate host.

BRUCELLOSIS IN CATTLE AND BUFFALOES IN BRAZIL: A BRIEF REVIEW

Brucellosis has been defined as a zoonotic disease affecting a myriad of species like bovine and buffalo’s herd. This disease has broadly been reported in many regions from Brazil which may give rises economic losses because of reproductive problems caused to the home farm animals, including the necrosis process within testicles resulting upon male sterility and birth of weak calf and retention of the fetal membrane upon female ruminants (SOUSA et al., 2015, 2017). Because abortion personifies the key symptom, brucellosis is usually referred to as Infectious Abortion, Contagious Abortion, or Bang Disease; each abortion occurred must be considered as brucellosis. The causer of brucellosis on cattle and buffaloes is a gram-negative coco-bacilli of the genus Brucella named Brucella abortus of which DNA may be found for about second to last pregnancy month within both maternal tissue and fetal fluid. Epidemiologically, the main infection pathway in buffaloes is the uterine transmission (SOUSA et al., 2015; LEITE and BASTIANETTO, 2009; SILVEIRA, 2006) but the transmissions encompass contact with bacteria including oral, conjunctive, and dermal pathways, natural mount, and artificial insemination for both cattle and buffaloes. There are no therapeutical treatments for brucellosis which may be diagnosed by either direct (PCR, bacterium isolation, and so forth) or indirect (serology) exam. Once diagnosed, the appropriate control commonly used is the elimination of reagent animals whereas may involve modulation in animal transit as well. The present paper categorizes and describes common diagnostics, transmission pathways, and control methods in cattle and buffaloes within signs of brucellosis. Moreover, it was hypothesized the age may relate with an immunological response with the subsequent incidence of such disease.

Effect of Herb-Partitioned Moxibustion on Autophagy and Immune-Associated Gene Expression Profiles in a Rat Model of Crohn’s Disease

Objective. To investigate the immune regulation mechanism of herb-partitioned moxibustion in rats with Crohn’s disease (CD) focusing on autophagy. Methods. Rats were randomly divided into normal (N) group, CD model (M) group, CD model with herb-partitioned moxibustion (MM) group, normal with herb-partitioned moxibustion (NM) group, CD model with mesalazine (western medicine, Med ) group, and normal saline (NS) group, with 10 rats in each group. The CD model rats were prepared by trinitrobenzene sulphonic expect for the N group and NM group. After the CD rats model were established, the rats in the MM and NM groups were treated with herb-partitioned moxibustion at Tianshu (ST25) and Qihai (CV6) acupoints once daily for 7 days, and rats in the Med and NS groups were respectively treated with mesalazine enteric coated tablet and normal saline once daily for 7 days. After intervention, hematoxylin-eosin staining was used to observe the histological changes of colon; RNA sequencing was used to observe the changes in autophagy- and immune-associated gene expression profiles. In addition, autophagy- and immune-associated cytokines and signaling pathways in CD rats were also screened. Results. HPM significantly increased the body weight of CD rats (P<0.01) and improved the pathological injury of colon in CD rats (P<0.01). HPM also changed the expression of many autophagy- and immune-associated genes, especially downregulating the expression of autophagy-associated Nod2, Irgm genes as well as the receptor of immune-associated Il12b, Il22 (Il12rb1, Il22ra2) genes in the colon of CD rats. HPM also changed the enrichment levels of differentially expressed genes in the human T-cell leukemia virus type-1 infection pathway, the Epstein-Barr virus infection pathway, and the cell adhesion molecule pathway. In addition, the expression levels of Nod2, Irgm, IL-12b, and IL-22 mRNA were increased (all P< 0.01) in the M group compared to the N group, while the expression levels of Nod2, Irgm, IL-12b, and IL-22 mRNA were decreased (P<0.05 or P<0.01) in the MM and Med groups compared to the M group. Conclusion. Herb-partitioned moxibustion may effectively attenuate intestinal inflammation and promote the repair of colon mucosal injury of CD rats through the regulation of autophagy- and immune-associated gene expression and signaling pathways.

Diffusion Theory for the Infection Pathway of Virus in a Living Cell

Background: The infection pathway of virus in living cell is of interest from the viewpoint of the physics of diffusion. Objective: Here, recent developments about a diffusion theory for the infection pathway of an adeno-associated virus in cytoplasm of a living HeLa cell are reported. Theories and Results: Generalizing fractional kinetics successfully modeling anomalous diffusion, a theory for describing the infection pathway of the virus over the cytoplasm is presented. The statistical property of the fluctuations of the anomalous-diffusion exponent is also discussed based on a maximum-entropy-principle approach. In addition, an issue regarding the continuum limit of the entropy introduced in the approach is carefully examined. The theory is found to imply that the motion of the virus may obey a scaling law.