Leaf-cutting ants are the most important pests in several cropping systems in the Neotropics. Granulated baits containing active ingredients, considered hazardous by the Stockholm Convention, are the ...usual method to control these ants. Isocycloseram is a new insecticide molecule with high safety margin for mammals, but without registration for the ants in general. Thus, this study investigated the effectiveness of granulated baits with isocycloseram in leaf-cutting ants control under laboratory and field conditions. Initially, the mortality of Atta sexdens workers, fed with dehydrated citrus pulp paste containing different concentrations of isocycloseram was evaluated in the laboratory for 21 days, for toxicological classification. Subsequently, the loading, devolution, and incorporation of baits with different concentrations of isocycloseram and the mortality of A. sexdens colonies were evaluated in the laboratory. After that, the percentages of loading and devolution of baits, foraging activity, and colony mortality treated with 0.05, 0.1, 0.2, and 0.3% of isocycloseram were evaluated for the species A. sexdens, A. laevigata, and Acromyrmex lundii in field conditions. All concentrations of isocycloseram killed more than 15% of ants in 24 h and more than 90% in 21 days in the laboratory, being classified as a fast-acting and highly effective active ingredient. Baits with 0.001 to 0.03% of isocycloseram were highly loaded and exhibited low rate of devolution. The mortality of A. sexdens colony was higher at concentrations between 0.075 and 0.3%, in the laboratory. Baits containing isocycloseram at concentrations of 0.2 and 0.3% were highly loaded, presented low devolution rates, and were highly efficient in controlling A. sexdens, A. laevigata, and A. lundii in the field, at dosages of 6, 10, and 12 g/m² of nest. This is the first report of the use of isocycloseram against leaf-cutting ants, contributing to the development of efficient and toxicologically safer ant baits.
Acromyrmex subterraneus molestans (Hymenoptera: Formicidae) is a leaf‐cutting ant species found in the Brazilian Cerrado and the Atlantic Forest and causes serious damages to cultivated plants. ...Knowledge about its foraging activity could help to improve the integrated pest management of this species and to better understand its ecology. The relationship between ambient temperature and the biomass collected by individuals of one Ac. subterraneus molestans colony was studied in the laboratory. The colony remained in an experimental room at 24°C and its foragers had access to an arena in an incubator set at six different temperatures (10, 16, 22, 28, 34 or 40°C). Fresh leaves of Hibiscus sp. were put in the arena and the flow of ants leaving and returning to the nest, the proportion of ants returning to the nest with a leaf fragment, as well as the dry mass of these fragments, were evaluated during 1 h for each temperature. The head width of foraging ants (laden and unladen) and their running speed were also measured. The rate of biomass collected was almost null at 10°C, increased from 16 to 34°C, and decreased abruptly at 40°C. The size of the workers did not vary across temperatures, and the running speed increased with increasing temperatures but more rapidly for unloaded ants than for loaded ones. The lower flow intensity at 28 and 40°C was somewhat compensated at the individual level by the selection of larger leaf fragments or by an increase in the probability to return loaded to the nest, respectively. The results obtained in this study could improve the management of these ants, allowing to target the most favourable meteorological conditions to apply toxic baits, increase the probability for the baits to be carried to the nest, in addition to reducing their availability to nontarget organisms. Furthermore, they could be used to make predictions on the effects of global warming on the foraging activity of this species.
The laden ants flow Acromyrmex subterraneus molestans is higher in mean temperatures than in higher or low temperatures.
The leaf‐cutter ant Ac. subterraneus molestans carried heavy fragments in mean temperatures than higher or low temperatures.
The walking speed of Ac. subterraneus molestans increases with increasing air temperature and laden ants are faster than unladen ones.
Leaf‐cutting ants change the walking speed, laden ants flow and weight of the fragments loaded, depending on weather conditions
There are few effective treatment options for patients with recurrent or metastatic head-and-neck squamous cell carcinoma. Pembrolizumab showed antitumour activity and manageable toxicity in ...early-phase trials. We aimed to compare the efficacy and safety of pembrolizumab versus standard-of-care therapy for the treatment of head-and-neck squamous cell carcinoma.
We did a randomised, open-label, phase 3 study at 97 medical centres in 20 countries. Patients with head-and-neck squamous cell carcinoma that progressed during or after platinum-containing treatment for recurrent or metastatic disease (or both), or whose disease recurred or progressed within 3–6 months of previous multimodal therapy containing platinum for locally advanced disease, were randomly assigned (1:1) in blocks of four per stratum with an interactive voice-response and integrated web-response system to receive pembrolizumab 200 mg every 3 weeks intravenously or investigator's choice of standard doses of methotrexate, docetaxel, or cetuximab intravenously (standard-of-care group). The primary endpoint was overall survival in the intention-to-treat population. Safety was analysed in the as-treated population. This trial is registered with ClinicalTrials.gov, number NCT02252042, and is no longer enrolling patients.
Between Dec 24, 2014, and May 13, 2016, 247 patients were randomly allocated to pembrolizumab and 248 were randomly allocated to standard of care. As of May 15, 2017, 181 (73%) of 247 patients in the pembrolizumab group and 207 (83%) of 248 patients in the standard-of-care group had died. Median overall survival in the intention-to-treat population was 8·4 months (95% CI 6·4–9·4) with pembrolizumab and 6·9 months (5·9–8·0) with standard of care (hazard ratio 0·80, 0·65–0·98; nominal p=0·0161). Fewer patients treated with pembrolizumab than with standard of care had grade 3 or worse treatment-related adverse events (33 13% of 246 vs 85 36% of 234). The most common treatment-related adverse event was hypothyroidism with pembrolizumab (in 33 13% patients) and fatigue with standard of care (in 43 18%). Treatment-related death occurred in four patients treated with pembrolizumab (unspecified cause, large intestine perforation, malignant neoplasm progression, and Stevens-Johnson syndrome) and two patients treated with standard of care (malignant neoplasm progression and pneumonia).
The clinically meaningful prolongation of overall survival and favourable safety profile of pembrolizumab in patients with recurrent or metastatic head and neck squamous cell carcinoma support the further evaluation of pembrolizumab as a monotherapy and as part of combination therapy in earlier stages of disease.
Merck Sharp & Dohme, a subsidiary of Merck & Co.
Three different species of hemoplasmas have been described in rodents, Mycoplasma coccoides, ‘Candidatus Mycoplasma haemomuris’ and ‘Candidatus Mycoplasma haemosphiggurus’. Additionally, potentially ...novel hemoplasma species have been detected in wild rodents from Brazil, including capybaras (Hydrochoerus hydrochaeris). Capybaras are the largest rodent in the world and are well adapted to live within close proximity to humans, which increases the risk to spread of zoonotic pathogens. Herein, we investigate the occurrence and genetic diversity of hemoplasmas infecting free-ranging capybaras from southern Brazil. Blood samples and ticks from 17 capybaras were collected. Packed cell volume and total plasma protein were measured, DNA was extracted, and further screened by species-specific and pan-hemoplasma PCR assays targeting the 16S rRNA gene of hemoplasmas. Sixteen out of 17 (94.12%; 95% CI: 73.02–98.95%) were anemic. Only one young female was hypoproteinemic. All capybaras were infested by adults and nymphs of Amblyomma dubitatum ticks. Using the PCR assay targeting the 16S rRNA gene of M. coccoides, 13/17 (76.47%; 95% CI: 52.74–90.44%) capybaras were positive for hemoplasmas. When DNA samples were tested by the pan-hemoplasma PCR, 16/17 (94.12%; 95% CI: 73.02–98.95%) animals were positive. One out of 11 (9.09%) adult ticks salivary glands tested positive for hemoplasma by the pan-hemoplasma PCR assay. Sequencing and phylogenetic analysis of the 16S and 23S rRNA gene fragments confirmed that animals were infected by a novel hemotropic Mycoplasma sp. previously reported in capybaras from Brazil. Additionally, sequencing and phylogenetic analysis of the 23S rRNA gene from three hemoplasma-positive capybaras samples from a previous study performed in midwestern Brazil also confirm our findings. Based on phylogenetic and Neighbor-Net network analysis of the 16S rRNA and 23S rRNA genes, the name ‘Candidatus Mycoplasma haematohydrochoerus’ is proposed for this novel organism.
•A novel hemoplasma species is highly prevalent in anemic capybaras infested by A. dubitatum ticks.•One adult Amblyomma dubitatum tick salivary glands tested positive for hemoplasma by PCR.•The name ‘Candidatus Mycoplasma haematohydrochoerus’ is proposed for this novel organism.
The RNA chaperone Hfq promotes the association of small RNAs (sRNAs) with cognate mRNAs, controlling the expression of bacterial phenotype.
mutants strains are attenuated for virulence in pigs, ...impaired in the ability to form biofilms, and more susceptible to stress, but knowledge of the extent of sRNA involvement is limited. Here, using
strain MIDG2331 (serovar 8), 14 sRNAs were identified by co-immunoprecipitation with Hfq and the expression of eight, identified as
-acting sRNAs, were confirmed by Northern blotting. We focused on one of these sRNAs, named Rna01, containing a putative promoter for RpoE (stress regulon) recognition. Knockout mutants of
and a double knockout mutant of
and
both had decreased biofilm formation and hemolytic activity, attenuation for virulence in
altered stress susceptibility, and an altered outer membrane protein profile. Rna01 affected extracellular vesicle production, size and toxicity in
. qRT-PCR analysis of
and putative cognate mRNA targets indicated that Rna01 is associated with the extracytoplasmic stress response. This work increases our understanding of the multilayered and complex nature of the influence of Hfq-dependent sRNAs on the physiology and virulence of
.
Secondary metabolites isolated from Simira eleiezeriana and Simira glaziovii were evaluated against herpes simplex virus (HSV-1) and (HSV-2). The 50% effective concentrations values (EC
50
) were ...calculated from the dose-response curve and the selectivity index (SI) against the virus. The physicochemical data LogP, (PSA), (NRB), (HBA) and (HBD) were obtained using Marvin Sketch. Among the tested compounds, conipheraldeyde, harman and simirane A showed better results with EC
50
6.39; 4.90; 4.61 µg/mL and SI 78.3; 11.8; 7.01, respectively, for HSV-1, and EC
50
41.2; 71.8; 3.73 µg/mL and SI 12.1; 24.7; 8.7, respectively, for HSV-2. The percentage of inhibition (PI) obtained for HSV-1 were higher than 60%, and for HSV-2 these compounds showed PI > 90%. The physical chemical data showed that the most active compounds satisfy the attributes for drugs with good oral bioavailability.
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