Evaluation of two artificial infection methods of live ticks as tools for studying interactions between tick-borne viruses and their tick vectors

Up to 170 tick-borne viruses (TBVs) have been identified to date. However, there is a paucity of information regarding TBVs and their interaction with respective vectors, limiting the development of new effective and urgently needed control methods. To overcome this gap of knowledge, it is essential to reproduce transmission cycles under controlled laboratory conditions. In this study we assessed an artificial feeding system (AFS) and an immersion technique (IT) to infect Ixodes ricinus ticks with tick-borne encephalitis (TBE) and Kemerovo (KEM) virus, both known to be transmitted predominantly by ixodid ticks. Both methods permitted TBEV acquisition by ticks and we further confirmed virus trans-stadial transmission and onward transmission to a vertebrate host. However, only artificial feeding system allowed to demonstrate both acquisition by ticks and trans-stadial transmission for KEMV. Yet we did not observe transmission of KEMV to mice (IFNAR−/− or BALB/c). Artificial infection methods of ticks are important tools to study tick-virus interactions. When optimally used under laboratory settings, they provide important insights into tick-borne virus transmission cycles.

Selection for resistance to broomrape race G in confectionary sunflower OP-population

The purpose of the work was to develop forms of confectionary sunflower resistant to broomrape race G on artificial infection background both in fields and greenhouses and artificial climate chambers. The researches were conducted in V.S. Pustovoit All-Russian Research Institute of Oil Crops, Krasnodar, Russia, in 2019–2021. A line RG (Or7) was used as a donor of gen of resistance to broomrape race G. The confectionary sunflower variety SPK plus was a recipient. Using methods of hybridization, back-crosses and group interpollination, on severe infection background, a sunflower population resistant to the aggressive broomrape race was develop for the further breeding of confectionary sunflower varieties. These methods allowed increasing resistance step-by-step while maintaining high polymorphism that makes it possible to continue breeding of confectionary sunflower varieties for the further rise of productivity.

Influence of laser irradiation on state of chlorophyll-containing tissues of apple trees infected with pathogenic bacterium Pseudomonas syringae

The study of the laser radiation impact on the functional state of the tissues of the apple-tree of the Antonovka ordinary variety showed that the use of coherent light enables to increase the level of photosynthetic activity. It is worth noting that the greatest effect of laser stimulation was observed in variants with artificial infection with the bacterium Pseudomonas syringae Van Hall (the causative agent of bacterial necrosis of fruit trees). This fact testifies to the activation of plant defense reactions against the pathogen. In this regard, the use of coherent light to increase plant resistance to pathogens is a promising direction for the development of organic farming.

Combination Breeding and Marker-Assisted Selection to Develop Late Blight Resistant Potato Cultivars

(1) Background: Although resistance to pathogens and pests has been researched in many potato cultivars and breeding lines with DNA markers, there is scarce evidence as to the efficiency of the marker-assisted selection (MAS) for these traits when applied at the early stages of breeding. A goal of this study was to estimate the potential of affordable DNA markers to track Rpi disease resistance genes, that are effective against the pathogen Phytophthora infestans, as a practical breeding tool on a progeny of 68 clones derived from a cross between the cultivar Sudarynya and 13/11-09. (2) Methods: this population was studied for four years to elucidate the distribution of LB resistance and other agronomical desirable or simple to phenotype traits such as tuber and flower pigmentation, capacity and structure of yield. LB resistance was phenotypically determined through natural and artificial infection and the presence/absence of nine Rpi genes was assessed via 11 sequence-characterized amplified region (SCAR) markers. To aid this analysis, the profile of Rpi genes in the 13/11-09 parent was established using diagnostic resistance gene enrichment sequencing (dRenSeq) as a gold standard. (3) Results: at the early stages of a breeding program, MAS can halve the workload when screening the segregation of F1 offspring and selected SCAR markers for Rpi-genes provide useful tools.

PSXIV-18 Genetic improvement for resistance to gastrointestinal parasitism in growing meat goats and hair sheep through a centralized performance test in the southcentral USA

Progress from selecting meat goats and hair sheep from different farms in the southcentral United States for resistance to internal parasitism during three consecutive central performance tests was evaluated. Tests entailed 7–10 wk of data collection after artificial infection of growing males with Haemonchus contortus larvae. There were 44, 50, and 50 Boer, Kiko, and Spanish goats and 54, 55, 34, and 47 Dorper, Katahdin-farm-A, Katahdin-farm-B, and St. Croix sheep, respectively. In year 1, males were randomly selected and in years 2 and 3 were progeny of sires and females classified as highly and moderately resistant. Criteria for males was average daily gain and residual feed intake during the performance test and means of fecal egg count (FEC) and packed cell volume after artificial infection and for females was FEC and FAMACHA on-farm. There were interactions in FEC of breed×year (P < 0.001) for both species (1,046; 1,134; and 2,630 for Boer; 3,781; 1,239; and 1,216 for Kiko; 1,303; 1,357; and 1,464 for Spanish; 3,288; 1,956; and 1,315 for Dorper; 1,528; 1,759; and 2,241 for Katahdin-A, 2,414; 3,874; and 1,793 for Katahdin-B; and 1,371; 1,160; and 1,175 eggs/g for St. Croix in years 1, 2, and 3, respectively) and year×resistance group (RG; P = 0.005) for goats (1,359; 610, and 552 for high; 1,951; 1,268; and 1,440 for moderate; 2,821; 1,852; and 3,118 eggs/g for low RG in years 1, 2, and 3, respectively) but not for sheep (P = 0.639). In conclusion, resistance appeared greatest for Spanish and St. Croix within species and was increased by selection of Kiko and Dorper. For highly resistant goats, lower FEC in year 2 and 3 vs. 1, compared with no year differences for moderate and low RG, indicates selection progress, and the lack of similar differences for sheep may reflect their relatively greater resistance.

Study on milky haemolymph diseases infection in wild and cultured of spiny lobster, Panulirus homarus in Indonesia

Milky Haemolymph Disease in Spiny Lobster (MHD-SL) is the most pathogenic diseases in spiny lobster (Panulirus homarus). Research on MHD-SL infection has not been undertaken in Indonesia. Therefore, present study aims to determine the infection of MHD-SL lobster. In 2016 a total of 240 lobsters for 30 each both from wild and cultured sample were collected from four locations (Candi Kusuma Bay of Bali Island, Gerupuk, Awang, and Telong-Elong Bays of Lombok Island) and in 2019, 50 lobster samples were collected for artificial infection study. While in January 2020, another 40 lobsters were collected from 2 different sites of culture (coastal and offshore cages) within Telong Elong Bay to determine infection of MHD-SL and for transmission study. The MHD-SL diseased was first check by clinical sign and confirmed by PCR-DNA molecular with specific primer of 254 bp. An experimental infection of MHD-SL was carried out by injection and cohabitation. The result showed that infected MHD-SL lobster shows inactive, loose appetite to eat, reddish and white colour of abdomen then moribund and all positive by PCR test. MHD-SL was found only in cultured lobster on the cages located at coastal water and no in the cages located at offshore within Telong-Elong Bay. In the experiment of artificial infection, either by injection or cohabitation, shows clinical sign of MHD-SL appeared at 8 days and all died after 14 days for both treatments. The present study approved that MHD-SL is pathogenic agent belonged to Rickettsia-like bacterium and infection occurred by horizontal transmission.

The effect of aortic esophageal fistula treatment after TEVAR with artificial vessel bypass（Single center clinical experience）

Objective: To investigate the effect of aortic esophageal fistula treatment after thoracic aortic endovascular repair (TEVAR) with artificial vessel bypass. Methods: The clinical data of 6 consecutive patients who received surgical treatment at Shanghai Deda Hospital from September 2019 to June 2021 due to aortic esophageal fistula after TEVAR were retrospectively analyzed. There were 6 males, aged (47.7±8.2) years old (range: 35-56 years old). All patients had recurrent fever, and 4 patients had positive blood cultures. According to the specific conditions of the patients, all patients underwent artificial blood vessel bypass and jejunostomy under general anesthesia without extracorporeal circulation. One case underwent artificially infected vascular segment resection and esophageal repair at the same time. 5 cases underwent artificial infection vascular resection, 4 of them underwent esophageal repair, and 1 case had a large intraoperative fistula and local resection of the esophagus. Sensitive antibacterial drugs were continued after the operation for 6 to 8 weeks. Results: There were 2 deaths in hospital, 1 case of large cerebral infarction early postoperatively, and 1 case of septic shock. The remaining 4 patients recovered well after the operation and were discharged. The follow-up period was 2 to 23 months. During the follow-up period, the remaining patients had no recurrence of infection and esophageal fistula. Conclusion ：In patients with aortic esophageal fistula after TEVAR, the establishment of artificial vascular bypass, the resection of the infected vascular segment, contemporaneous or staged esophageal repair, regular anti-infective treatment can obtain a good prognosis.

Characterization and evaluation of a recombinant multiepitope peptide antigen MAG in the serological diagnosis of Toxoplasma gondii infection in pigs

Background Toxoplasmosis caused by Toxoplasma gondii is a serious disease threatening human and animal health. People can be infected with T. gondii by ingesting raw pork contaminated with cysts or oocysts. Serological test is a sensitive and specific method usually used for large-scale diagnosis of T. gondii infection in humans and animals (such as pigs). Commercial pig Toxoplasma antibody ELISA diagnostic kits are expensive, which limits their use; moreover, the wide antigen composition used in these diagnostic kits is still unclear and difficult to standardize. The multiepitope peptide antigen is a novel diagnostic marker, and it has potential to be developed into more accurate and inexpensive diagnostic kits. Methods The synthetic multiepitope antigen (MAG) cDNA encoding a protein with epitopes from five T. gondii-dominant antigens (SAG1, GRA1, ROP2, GRA4, and MIC3) was designed, synthesized, and expressed in Escherichia coli BL21 (DE3) strain. The recombinant protein was detected through western blot with pig anti-T. gondii-positive and -negative serum, and then IgG enzyme-linked immunosorbent assay (ELISA) named MAG-ELISA was designed. The MAG-ELISA was evaluated in terms of specificity, sensitivity, and stability. The MAG-ELISA was also compared with a commercial PrioCHECK®Toxoplasma Ab porcine ELISA (PrioCHECK ELISA). Finally, the trend of pig anti-T. gondii IgG levels after artificial infection with RH tachyzoites was evaluated using MAG-ELISA and two other ELISA methods (rMIC3-ELISA and PrioCHECK ELISA). Results MAG antigen could be specifically recognized by pig anti-T. gondii-positive but not -negative serum. MAG-ELISA showed high diagnostic performance in terms of specificity (88.6%) and sensitivity (79.1%). MAG-ELISA could be used for detecting anti-T. gondii IgG in the early stage of T. gondii infection in pigs (at least 7 days after artificial infection). Conclusions Our results suggest that MAG antigen can be applied to specifically recognize anti-T. gondii IgG in pig, and MAG-ELISA has the potential for large-scale screening tests of T. gondii infection in pig farms and intensive industries. Graphical abstract

Alnus glutinosa Threatened by Alder Phytophthora: A Histological Study of Roots

Alder dieback remains a major problem in European alder stands and its spread continues to threaten their existence. The causal agent of this disease is the so-called alder Phytophthora species complex, which includes the hybrid Phytophthora ×alni and its parental species P. uniformis and P. ×multiformis. Little is known about the survival of these Phytophthora species in alder. The aim of our investigations was to find out whether, and if so where, the pathogen survives. The subject of these studies was alder roots. Therefore, artificial infection studies and histological studies with P. ×alni and P. uniformis were carried out on seedlings of black alder (Alnus glutinosa). These histological studies revealed oogonia and oospores of P. ×alni and P. uniformis in different parts of the root tissue.