Effects of summer treatments against Varroa destructor on viral load and colony performance of Apis mellifera colonies in Eastern Canada.

Despite the use of various integrated pest management strategies to control the honey bee mite, Varroa destructor, varroosis remains the most important threat to honey bee colony health in many countries. In Canada, ineffective varroa control is linked to high winter colony losses and new treatment options, such as a summer treatment, are greatly needed. In this study, a total of 135 colonies located in 6 apiaries were submitted to one of these 3 varroa treatment strategies: (i) an Apivar® fall treatment followed by an oxalic acid (OA) treatment by dripping method; (ii) same as in (i) with a summer treatment consisting of formic acid (Formic Pro™); and (iii) same as in (i) with a summer treatment consisting of slow-release OA/glycerin pads (total of 27 g of OA/colony). Treatment efficacy and their effects on colony performance, mortality, varroa population, and the abundance of 6 viruses (acute bee paralysis virus [ABPV], black queen cell virus [BQCV], deformed wing virus variant A [DWV-A], deformed wing virus variant B [DWV-B], Israeli acute paralysis virus [IAPV], and Kashmir bee virus [KBV]) were assessed. We show that a strategy with a Formic Pro summer treatment tended to reduce the varroa infestation rate to below the economic fall threshold of 15 daily varroa drop, which reduced colony mortality significantly but did not reduce the prevalence or viral load of the 6 tested viruses at the colony level. A strategy with glycerin/OA pads reduced hive weight gain and the varroa infestation rate, but not below the fall threshold. A high prevalence of DWV-B was measured in all groups, which could be related to colony mortality.

One-carbon unit supplementation fuels purine synthesis in tumor-infiltrating T cells and augments checkpoint blockade.

Nucleotides perform important metabolic functions, carrying energy and feeding nucleic acid synthesis. Here, we use isotope tracing-mass spectrometry to quantitate contributions to purine nucleotides from salvage versus de novo synthesis. We further explore the impact of augmenting a key precursor for purine synthesis, one-carbon (1C) units. We show that tumors and tumor-infiltrating T cells (relative to splenic or lymph node T cells) synthesize purines de novo. Shortage of 1C units for T cell purine synthesis is accordingly a potential bottleneck for anti-tumor immunity. Supplementing 1C units by infusing formate drives formate assimilation into purines in tumor-infiltrating T cells. Orally administered methanol functions as a formate pro-drug, with deuteration enabling kinetic control of formate production. Safe doses of methanol raise formate levels and augment anti-PD-1 checkpoint blockade in MC38 tumors, tripling durable regressions. Thus, 1C deficiency can gate antitumor immunity and this metabolic checkpoint can be overcome with pharmacological 1C supplementation.

Evaluation of in-feed supplementation of formic acid and thymol as non-antibiotic growth promoters and assessing their effect on antimicrobial resistant E.coli isolated in Turkey.

With the rampant usage of antibiotics as growth promoters (AGPs) in poultry sector, there has been alarming concerns of antimicrobial resistant microbes such as Escherichia coli. Diversification of poultry farming due to consumer demand for safer products with higher protein content, turkey production is gaining popularity. Feed additives such as formic acid (FA) and thymol (TH) are effectively replacing AGPs due to their antimicrobial action. This directed the researchers to find alternatives to antibiotics such as thymol and formic acid because of their strong antimicrobial, anti-oxidative, digestive-stimulating properties. To assess the efficacy of FA and TH as growth promoters and their effect on the antimicrobial resistance (AMR) load, the current study (0-12 weeks) was conducted in CARI VIRAT turkey poults (n = 256; unsexed) those were randomly distributed into eight treatment groups: control(T1), AGP (T2), graded levels of FA (T3 to T5) @ 2.5, 5 and 7.5 ml/kg and TH (T6 to T8) @ 120, 240 and 350 mg/kg. Cloacal swab samples were collected at 0, 4th, 8th and 12th week interval and processed further for isolation, identification and assessment of resistance profile of E. coli. The final body weight, cumulative gain and FCR were significantly (p < 0.05) better for birds under supplementation. The Total plate count (TPC) and coliforms showcased a significant (p < 0.001) reduction in the FA and TH supplement groups as compared to control and AGP group. The resistance profile indicated E. coli isolates from AGP group with significantly (p < 0.001) highest resistivity against antibiotics (viz. chloramphenicol, tetracycline, nalidixic acid, chlortetracycline) while isolates from FA (T5) and TH (T8) groups were the least resistant. blaAmpC gene was significantly (p < 0.001) harbored in T2 isolates whereas least detected in T5 and T8. It was inferred that formic acid (7.5 ml/kg) and thymol (360 mg/kg) can effectively replace AGPs and lower AMR burden in poultry.