Phytotherapy for treatment of cytokine storm in COVID-19.

In 2020, a novel strain of coronavirus (COVID-19) has led to a significant morbidity and mortality worldwide. As of the date of this writing, a total of 116 M cases has been diagnosed worldwide leading to 2.5 M deaths. The number of mortalities is directly correlated with the rise of innate immune cells (especially macrophages) in the lungs that secrete inflammatory cytokines (IL-1ß and IL-6) leading to the development of "Cytokine Storm Syndrome" (CSS), multi-organ-failure and death. Given that currently the treatment of this condition is rare and release of effective vaccine might be months away, here, we review the plants and their pharmacologically active-compounds as potential phytopharmaceuticals for the virus induced inflammatory response. Experimental validation of the effectiveness of these natural compounds to prevent or reduce the cytokine storm might be beneficial as an adjunct treatment of SARS-CoV-2.

A novel therapeutic antibody screening method using bacterial high-content imaging reveals functional antibody binding phenotypes of Escherichia coli ST131.

The increase of antimicrobial resistance (AMR), and lack of new classes of licensed antimicrobials, have made alternative treatment options for AMR pathogens increasingly attractive. Recent studies have demonstrated anti-bacterial efficacy of a humanised monoclonal antibody (mAb) targeting the O25b O-antigen of Escherichia coli ST131. To evaluate the phenotypic effects of antibody binding to diverse clinical E. coli ST131 O25b bacterial isolates in high-throughput, we designed a novel mAb screening method using high-content imaging (HCI) and image-based morphological profiling to screen a mAb targeting the O25b O-antigen. Screening the antibody against a panel of 86 clinical E. coli ST131 O25:H4 isolates revealed 4 binding phenotypes: no binding (18.60%), weak binding (4.65%), strong binding (69.77%) and strong agglutinating binding (6.98%). Impaired antibody binding could be explained by the presence of insertion sequences or mutations in O-antigen or lipopolysaccharide core biosynthesis genes, affecting the amount, structure or chain length of the O-antigen. The agglutinating binding phenotype was linked with lower O-antigen density, enhanced antibody-mediated phagocytosis and increased serum susceptibly. This study highlights the need to screen candidate mAbs against large panels of clinically relevant isolates, and that HCI can be used to evaluate mAb binding affinity and potential functional efficacy against AMR bacteria.

Calcium is involved in the R Mc1 (blb)-mediated hypersensitive response against Meloidogyne chitwoodi in potato.

KEY MESSAGE: Functional characterization of the Columbia root-knot nematode resistance gene R Mc1 ( blb ) in potato revealed the R gene-mediated resistance is dependent on a hypersensitive response and involves calcium. The resistance (R) gene R Mc1(blb) confers resistance against the plant-parasitic nematode, Meloidogyne chitwoodi. Avirulent and virulent nematodes were used to functionally characterize the R Mc1(blb)-mediated resistance mechanism in potato (Solanum tuberosum). Histological observations indicated a hypersensitive response (HR) occurred during avirulent nematode infection. This was confirmed by quantifying reactive oxygen species activity in response to avirulent and virulent M. chitwoodi. To gain an insight into the signal transduction pathways mediating the R Mc1(blb)-induced HR, chemical inhibitors were utilized. Inhibiting Ca(2+) channels caused a significant reduction in electrolyte leakage, an indicator of cell death. Labeling with a Ca(2+)-sensitive dye revealed high Ca(2+) levels in the root cells surrounding avirulent nematodes. Furthermore, the calcium-dependent protein kinase (CDPK), StCDPK4 had a higher transcript level in R Mc1(blb) potato roots infected with avirulent nematodes in comparison to roots infected with virulent M. chitwoodi. The results of this study indicate Ca(2+) plays a role in the R Mc1(blb)-mediated resistance against M. chitwoodi in potato.

Enzymatic variability among Brazilian Pythium insidiosum isolates

Background. Pythium insidiosum is an oomycete classified in the kingdom Stramenopila. P. insidiosum hyphae are not able to initiate infection without the secretion of hydrolytic enzymes, which are considered an important factor in microbial virulence. Aims. To evaluate the extracellular enzymatic activity of 14 Brazilian P. insidiosum isolates and a standard strain (ATCC 58637) by the API-ZYM System screening method. Methods. Zoospores were grown in RPMI 1640 broth, and 65 μL of the liquid phase were inoculated in each cupule of the API-ZYM strips. Results. Differences in the enzymatic activities were observed among the isolates, although phosphohydrolases and ester hydrolases were conspicuous among all isolates. β-glucosidase was also present in most of the isolates. Enzymatic activities of β-glucosidase and chymotrypsin were not observed, differing from a previous study involving Australian isolates and intracellular enzymes. Conclusions. The discrepancy in the enzymatic profile observed among Brazilian P. insidiosum isolates reflects the phenotypic variations found in susceptibility tests

ß-Glucan plus ascorbic acid in neonatal calves modulates immune functions with and without Salmonella enterica serovar Dublin.

To determine if ß-glucan plus ascorbic acid affects adherence and pathogenicity of Salmonella Dublin and innate immune response in neonatal calves, 20 calves were fed control or supplemented diets (ß-glucan, 0.9 g/d, plus ascorbic acid, 500 mg/d) until d 23. On d 21, 5 calves per treatment received 2.4 × 10(8)CFU of S. Dublin orally. S. Dublin spread through intestinal tissues into mesenteric lymph nodes (MLN), spleen, and lung tissues within 48 h. All supplemented calves had less mRNA expression of IL-1 receptor antagonist in liver. Leukocyte cell surface markers changed in lung cells, but not in blood, MLN, or spleen. CD14 in lungs was greatest for calves receiving supplement and challenge, but CD18 in lungs was greater for challenged than control calves. Lung DEC205 was greatest for challenged calves with and without supplement compared to controls, but more lung cells expressed CD14 for all treated groups compared to controls. These data show that S. Dublin briefly inhabited the intestinal tract, moving quickly to spleen, MLN, and lung tissues. Lung tissue was modulated by S. Dublin, but supplement alone increased CD14 expressing cells. The supplement appears not to attenuate invasiness but modified some lung cell populations by 48h.

An approach to obtain specific polyclonal antisera to Xanthomonas campestris pv. cyamopsidis and its potential application in indexing of infected seeds of guar.

Clusterbean seed health testing is warranted since the pathogen (Xanthomonas campestris pv. cyamopsidis (Xccy)) is seed-borne and seed-transmitted. A polyclonal antibody was developed in rabbit via subcutaneous and intramuscular injections and characterized for sensitivity, specificity and its applicability to ELISA which: (i) was sensitive in detecting as few as 102 cells ml - 1 at a titre of 1: 4000; (ii) was specific, since it reacted only with Xccy and not with other xanthomonads; (iii) reacted both with Xccy cells and culture filtrate, indicating that the antigenic determinant is a secretory component; (iv) was applicable and reliable in seed health testing since it reacted only with infected seeds and plant materials and not with healthy seeds and (v) a purified fraction of antibody was virulent-specific since heat-denatured and avirulent isolates were not detected. The ELISA thus developed is highly reproducible and therefore suitable for the evaluation of the potential disease status of seeds and plant health, which is appropriate for routine seed health testing.

[The outlook for the development of live vaccines for the prevention of melioidosis]. / Perspektivy razrabotki zhivykh vaktsin dlia profilaktiki melioidoza.

The effectiveness of immunization with Burkholderia pseudomallei attenuated strains (Pur and Ts), heterologous vaccines and the recombinant culture of Francisella tularensis RM2 carrying a plasmid with fragments of B. pseudomallei chromosome was studied in four species of experimental animals, essentially differing in their sensitivity to melioidosis. The most immunogenic B. pseudomallei mutants, introduced subcutaneously, created a statistically significant level of protection in animals, moderately sensitive to melioidosis, but proved to be ineffective in highly sensitive animal models when tested under the same conditions. In aerogenic infection the effectiveness of the experimental vaccines under study in all species of the animals was on the same level. The study showed good prospects of using tularemia vaccine for inducing heterologous immunity to melioidosis, as well as the possibility of its use as the basis of a bivalent gene-engineering vaccine.

Immunization with bacterial antigens: furunculosis.

Although the nature of the antigens and the immune responses they elicit to achieve immunity to furunculosis are still not well defined, the currently available vaccines comprising A. salmonicida bacterins emulsified in oil adjuvants and delivered by intraperitoneal injection provide remarkably high levels of long-lasting protection. Despite some concern over side-effects, these vaccines have been adopted by most Atlantic salmon farmers over the last four years, transforming a situation where furunculosis outbreaks were becoming catastrophic to one where losses from the disease are negligible. Present evidence indicates that antibody responses to the polysaccharide capsule and iron regulated outer membrane proteins are associated with protection. Furthermore, cell-mediated immune responses involving antigen-induced release of cytokines from lymphocytes and the resultant activation of macrophages with the ability to kill the pathogen are also considered important protective mechanisms. Vaccines comprising whole A. salmonicida cultures grown under iron-restricted conditions and delivered by injection in an oil adjuvant are expected to induce prolonged stimulation of all the above responses. While these vaccines are suitable and effective for administration to salmon smolts there is still a need for mass vaccination by immersion or oral routes for salmonid fry. Effective means of achieving this are still required.

[The immunological activity of the bacterial strain Escherichia coli M17 used in preparing a commercial preparation of colibacterin]. / Immunologicheskaia aktivnost' bakterii shtamma Escherichia coli M17, ispol'zuemogo pri izgotovlenii kommercheskogo preparata kolibakterina.

The toxicity, immunogenic properties and protective activity of the live culture of E. coli M17 and antigenic preparations obtained from cell suspensions of this strain have been studied under experimental conditions. As revealed in experiments on mice, E. coli M17 live culture has low virulence, moderate toxicity and provides the protection of immunized mice from challenge with homologous and highly virulent E. coli strains. E. coli M17 live culture, when introduced orally or intravenously into rabbits, ensures the synthesis of 02 and H6 antibodies. Blood sera taken from immunized rabbits yield better results than initial sera in experiments on the passive protection of mice. The results of our experiments show the expediency of the clinical trials of Colibacterin as a perspective Escherichia live oral vaccine.

[The preventive activity of monoclonal antibodies specific to the lipopolysaccharide of Francisella tularensis]. / Preventivnaia aktivnost' monoklonal'nykh antitel, spetsifichnykh k lipopolisakharidu Francisella tularensis.

The preventive activity of five monoclonal antibodies (McAb) in experimental tularemia was evaluated. McAb produced by hybridoma FB11-k (IgG2a), specific to F. tularensis lipopolysaccharide, prevented the death of mice and guinea pigs infected with F. tularensis virulent strain 503 of the holarctic subspecies.