Reviewing the effect of aggregates in Rhodamine 6G aqueous solution on fluorescence quantum efficiency.

Rhodamines constitute a class of dyes extensively investigated and applied in various contexts, primarily attributed to their high luminescence quantum yield. This study delves into the impact of aggregation on the thermal and optical properties of Rhodamine 6G (R-6G) solutions in distilled water. Examined properties encompass thermal diffusivity (D), temperature coefficient of the refractive index (dn/dT), fluorescence quantum efficiency (η), and energy transfer (ET). These parameters were assessed through thermal lens (TL) and conventional absorption and emission spectroscopic techniques. The dimerization of R-6G solutions was revisited, revealing that an increase in R-6G concentration alters the features of absorption and emission spectra due to dimer formation, resulting in unexpected behavior of η. Consequently, we introduce a novel model for the fraction of absorbed energy converted into heat (φ), which accounts for emissions from both monomers and dimers. Employing this model, we investigate and discuss the concentration-dependent behaviors of η for monomers (ηm) and dimers (ηd). Notably, our findings demonstrate that ηm values necessitate ηd = 0.2, a relatively substantial value that cannot be disregarded. Additionally, applying the Förster theory for dipole-dipole electric ET, we calculate microparameters for ET between monomers (CDD) and monomer-dimer (CDA). Critical ranges for ET in each case are quantified. Microparameter analysis indicates that ET between monomer-monomer and monomer-dimer species of R-6G dissolved in distilled water holds significance, particularly in determining ηm. These results bear significance, especially in scenarios involving high dye concentrations. While applicable to R-6G in water, similar assessments in other media featuring aggregates are encouraged.

MAIT cell activation is reduced by direct and microbiota-mediated exposure to bisphenols.

Oral uptake is the primary route of human bisphenol exposure, resulting in an exposure of the intestinal microbiota and intestine-associated immune cells. Therefore, we compared the impact of bisphenol A (BPA), bisphenol F (BPF) and bisphenol S (BPS) on (i) intestinal microbiota, (ii) microbiota-mediated immunomodulatory effects and (iii) direct effects on mucosal-associated invariant T (MAIT) cells in vitro. We acutely exposed human fecal microbiota, Bacteroides thetaiotaomicron and Escherichia coli to BPA and its analogues BPF and BPS referring to the European tolerable daily intake (TDI), i.e. 2.3 µg/mL, 28.3 µg/mL and 354.0 µg/mL. Growth and viability of E. coli was most susceptible to BPF, whereas B.thetaiotaomicron and fecal microbiota were affected by BPA > BPF > BPS. At 354.0 µg/mL bisphenols altered microbial diversity in compound-specific manner and modulated microbial metabolism, with BPA already acting on metabolism at 28.3 µg/mL. Microbiota-mediated effects on MAIT cells were observed for the individual bacteria at 354.0 µg/mL only. However, BPA and BPF directly modulated MAIT cell responses at low concentrations, whereby bisphenols at concentrations equivalent for the current TDI had no modulatory effects for microbiota or for MAIT cells. Our findings indicate that acute bisphenol exposure may alter microbial metabolism and impact directly on immune cells.

Metagenomic insights into the taxonomy, function, and dysbiosis of prokaryotic communities in octocorals.

BACKGROUND: In octocorals (Cnidaria Octocorallia), the functional relationship between host health and its symbiotic consortium has yet to be determined. Here, we employed comparative metagenomics to uncover the distinct functional and phylogenetic features of the microbiomes of healthy Eunicella gazella, Eunicella verrucosa, and Leptogorgia sarmentosa tissues, in contrast with the microbiomes found in seawater and sediments. We further explored how the octocoral microbiome shifts to a pathobiome state in E. gazella. RESULTS: Multivariate analyses based on 16S rRNA genes, Clusters of Orthologous Groups of proteins (COGs), Protein families (Pfams), and secondary metabolite-biosynthetic gene clusters annotated from 20 Illumina-sequenced metagenomes each revealed separate clustering of the prokaryotic communities of healthy tissue samples of the three octocoral species from those of necrotic E. gazella tissue and surrounding environments. While the healthy octocoral microbiome was distinguished by so-far uncultivated Endozoicomonadaceae, Oceanospirillales, and Alteromonadales phylotypes in all host species, a pronounced increase of Flavobacteriaceae and Alphaproteobacteria, originating from seawater, was observed in necrotic E. gazella tissue. Increased abundances of eukaryotic-like proteins, exonucleases, restriction endonucleases, CRISPR/Cas proteins, and genes encoding for heat-shock proteins, inorganic ion transport, and iron storage distinguished the prokaryotic communities of healthy octocoral tissue regardless of the host species. An increase of arginase and nitric oxide reductase genes, observed in necrotic E. gazella tissues, suggests the existence of a mechanism for suppression of nitrite oxide production by which octocoral pathogens may overcome the host's immune system. CONCLUSIONS: This is the first study to employ primer-less, shotgun metagenome sequencing to unveil the taxonomic, functional, and secondary metabolism features of prokaryotic communities in octocorals. Our analyses reveal that the octocoral microbiome is distinct from those of the environmental surroundings, is host genus (but not species) specific, and undergoes large, complex structural changes in the transition to the dysbiotic state. Host-symbiont recognition, abiotic-stress response, micronutrient acquisition, and an antiviral defense arsenal comprising multiple restriction endonucleases, CRISPR/Cas systems, and phage lysogenization regulators are signatures of prokaryotic communities in octocorals. We argue that these features collectively contribute to the stabilization of symbiosis in the octocoral holobiont and constitute beneficial traits that can guide future studies on coral reef conservation and microbiome therapy. Video Abstract.

Comparative efficacy evaluation of moxidectin gel and ivermectin paste against internal parasites of equines in Brazil.

A total of 24 male and female equines of mixed breed, 10-20 months of age and naturally infected with internal parasites was utilized in a controlled test to evaluate the efficacy of a moxidectin 2% gel formulation at the dosage of 0.4 mg moxidectin per kg of live weight and an ivermectin 1.87% commercial paste formulation at the dosage 0.2 mg ivermectin per kg applied orally. Animals were allocated into three groups of eight horses each based on pre-treatment eggs per gram (EPG) counts and treatments were randomized among the groups. One group was kept as untreated controls. One animal in the moxidectin-treated group died before the end of the trial from a cause unrelated to treatment leaving a total of seven animals in this group. Fecal egg counts were performed three times post-treatment and the number of parasites remaining in each animal was determined. Statistical analyses using geometric means were performed at the 1% level of significance. Both moxidectin and ivermectin preparations reduced initial EPG from a mean of 1600 to 0 on Days 5, 7 and at the end of the trial on Day 14. Efficacy percentages of moxidectin and ivermectin against immature and adult nematodes were as follows: Trichostrongylus axei, Parascaris equorum, Strongylus edentatus, S. vulgaris, Triodontophorus spp. and Gyalocephalus capitatus, 100% for both products; Habronema muscae 99.5 and 99.6%, respectively, Strongyloides westeri, 100 and 99.2%, respectively; Oxyuris equi, 99.6 and 100%, respectively; small strongyles, 99.7% for both products. Of the latter, the most numerous were: Cylicocyclus insigne, Cylicostephanus longibursatus and Cyathostomum catinatum. No Gasterophilus nasalis were found in horses from either treated group, while two of eight control horses had infections with thisparasite. Moxidectin showed greater efficacy (84.9%) than ivermectin (67.8%) against Strongylus vulgaris larvae found in the mesenteric artery aneurisms, but the difference was not statistically significant. Total parasite counts for both treated groups were significantly lower (p<0.01) than in the non-treated group. No significant differences were noted between moxidectin and ivermectin. Efficacy against the 30 nematode species found in this study was very evident for both products. As expected, neither moxidectin nor ivermectin was effective in controlling the tapeworm Anoplocephala perfoliata. No adverse reactions were observed during the experimental period.

A comparative study of lesions caused by different parasite stages of Boophilus microplus (Canestrini) in the skins of naturally infested taurine and zebuine hosts. The correlation of tick resistence with mast cell counts in the host's skin

Biópsias de pele lesada por larvas, ninfas e fêmeas engurgitadas de Boophilus microplus foram colhidas de cinco Bos taurus da raça Holandesa e de cinco Bos indicus da raça Gir, adquiridos na mesma propriedade, com aproximadamente 23 meses de idade, e colocados em convivência no mesmo pasto durante 90 dias que precederam este ensaio. O grau de susceptibilidade ao ácaro foi estimado previamente, sendo os zebuínos cerca de 15 vezes mais resistentes que os taurinos. As biópsias foram colhidas de modo que o parasito ficasse localizado no centro do fragmento de pele. Essas peças foram fixadas em formalina a 10 por cento durante 24 h e processadas pelos métodos usuais em histologia seguindo-se a coloraçäo pela técnica da Hematoxilin-Eosin ou do "tricrômico" de Masson. Näo foram constatadas diferenças morfológicas que pudessem ser relacionadas aos diferentes graus de resistência ao parasito entre os taurinos e zebuínos. Biópsias foram colhidas de zonas näo lesadas, na regiäo da virilha dos cinco taurinos e dos cinco zebuínos, fixadas em subacetato de chumbo a 1 por cento em soluçäo de etanol 50 por cento, contendo 1 por cento de ácido acético, por 24 h. A seguir os fragmentos foram processados pelas técnicas usuais em histologia e corados pelo método do azul de toluidina 0,1 por cento. Os mastócitos foram contados comparativamente em 80 campos microscópicos, em aumento de 100 vezes. Os resultados mostram que os zebuínos tem mais que o dobro do número de mastócitos dérmicos quando comparado com o encontrado nos taurinos. Esses resultados sugerem que os mastócitos dérmicos possam, pelo menos em parte, participar dos mecanismos de resistência dos bovinos ao Boophilus microplus

A technique for collecting saliva from the cattle-tick Boophilus microplus (canestrini, 1887) using chemical stimulation: environmental and temporal influences on secretion yield

1. Injection of a pilocarpine solution into the hemocoele of female B. microplus through the respiratory spiracle induced the flow of limpid saliva, collected from the mouth parts with a capillary tube. 2. The time interval between the detachment of the tick from its host and chemical stimulation influenced the volume of saliva secreted; secretion was greater during the first 2 h after detachment. 3. There is a positive correlation between salivary yield and both environmental temperature and relative humidity

A technique for collecting saliva from the cattle-tick Boophilus microplus (Canestrini, 1887) using chemical stimulation. Environmental and temporal influences on secretion yield.

1. Injection of a pilocarpine solution into the hemocoele of female B. microplus through the respiratory spiracle induced the flow of limpid saliva, collected from the mouth parts with a capillary tube. 2. The time interval between the detachment of the tick from its host and chemical stimulation influenced the volume of saliva secreted; secretion was greater during the first 2 h after detachment. 3. There is a positive correlation between salivary yield and both environmental temperature and relative humidity.

[Distribution of the genus Ancylostoma (Dubini, 1843) along the digestive tube of the dog (author's transl)]. / Localização do gênero Ancylostoma (Dubini, 1843) no tubo gastrointestinal do cão.

The A. A. studied the distribution of nematodes of the genus Ancylostoma (Dubini, 1843) along the digestive tube of 45 dogs. For the collection of the worms they used the method developed by Mello and Campos. The distribution found was: 97,5% in the jejunum, 1,2% in the ileon, 0,7% in the duodenum, 0,3% in the colon, 0,2% in the cecum and 0,1% in the stomach.