Biosynthesis of Nanoparticles Using Plant Extracts and Essential Oils.

Plant extracts and essential oils have a wide variety of molecules with potential application in different fields such as medicine, the food industry, and cosmetics. Furthermore, these plant derivatives are widely interested in human and animal health, including potent antitumor, antifungal, anti-inflammatory, and bactericidal activity. Given this diversity, different methodologies were needed to optimize the extraction, purification, and characterization of each class of biomolecules. In addition, these plant products can still be used in the synthesis of nanomaterials to reduce the undesirable effects of conventional synthesis routes based on hazardous/toxic chemical reagents and associate the properties of nanomaterials with those present in extracts and essential oils. Vegetable oils and extracts are chemically complex, and although they are already used in the synthesis of nanomaterials, limited studies have examined which molecules are effectively acting in the synthesis and stabilization of these nanostructures. Similarly, few studies have investigated whether the molecules coating the nanomaterials derived from these extracts and essential oils would bring benefits or somehow reduce their potential activity. This synergistic effect presents a promising field to be further explored. Thus, in this review article, we conducted a comprehensive review addressing the main groups of molecules present in plant extracts and essential oils, their extraction capacity, and available methodologies for their characterization. Moreover, we highlighted the potential of these plant products in the synthesis of different metallic nanomaterials and their antimicrobial capacity. Furthermore, we correlated the extract's role in antimicrobial activity, considering the potential synergy between molecules from the plant product and the different metallic forms associated with nanomaterials.

Effects of stress exposure in captivity on physiology and infection in avian hosts: no evidence of increased Borrelia burgdorferi s.l. infectivity to vector ticks.

Exposure to environmental stressors, an increasingly recurring event in natural communities due to anthropogenic-induced environmental change, profoundly impacts disease emergence and spread. One mechanism through which this occurs is through stress-induced immunosuppression increasing disease susceptibility, prevalence, intensity and reactivation in hosts. We experimentally evaluated how exposure to stressors affected both the physiology of avian hosts and the prevalence of the zoonotic bacteria Borrelia burgdorferi sensu lato (s.l.), in two model species-the blackbird Turdus merula and the robin Erithacus rubecula captured in the wild, using xenodiagnoses and analysis of skin biopsies and blood. Although exposure to stressors in captivity induced physiological stress in birds (increased the number of circulating heterophils), there was no evidence of increased infectivity to xenodiagnostic ticks. However, Borrelia detection in the blood for both experimental groups of blackbirds was higher by the end of the captivity period. The infectivity and efficiency of transmission were higher for blackbirds than robins. When comparing different methodologies to determine infection status, xenodiagnosis was a more sensitive method than skin biopsies and blood samples, which could be attributed to mild levels of infection in these avian hosts and/or dynamics and timing of Borrelia infection relapses and redistribution in tissues.

TiO2 Nanocrystals and Annona crassiflora Polyphenols Used Alone or Mixed Impact Differently on Wound Repair.

Wounds treated with TiO2 nanoparticles (TiO2-NPs) show an improvement in healing time. However, little is known about the parameters that can contribute to this result. On the other hand, the treatment of wounds with polyphenols is widely known. These compounds are found in the peel of Annona crassiflora fruit and have antioxidant, analgesic and anti-inflammatory properties. In this study, we evaluated the healing effect of TiO2 nanocrystals (TiO2-NCs), polyphenolic fractions obtained from ethanolic extract of A. crassiflora fruit peel (PFAC) and mix (PFAC + TiO2-NCs) on the parameters of wound closure, inflammation, collagen deposition, metalloproteinase activity (MMPs) and angiogenesis. TiO2-NCs and PFAC have activity for wound healing, showed anti-inflammatory action and a shorter wound closure time. These treatments also contributed to increased collagen deposition, while only treatment with TiO2-NCs increased MMP-2 activity, parameters essential for the migration of keratinocytes and for complete restoration of the injured tissue. The combination of PFAC + TiO2-NCs reduced the effectiveness of individual treatments by intensifying the inflammatory process, in addition to delaying wound closure. We conclude that the interaction between the hydroxyl groups of PFAC polyphenols with TiO2-NCs may have contributed to difference in the healing activity of skin wounds.

Quality of recovery in patients under low- or standard-pressure pneumoperitoneum. A randomised controlled trial.

BACKGROUND: The use of low-pressure pneumoperitoneum seems to be capable of reducing complications such as post-operative pain. However, the quality of evidence supporting this conclusion is low. Both the lack of investigator blinding to both intra-abdominal pressure and to method of neuromuscular blockade represent key sources of bias. Hence, this prospective, randomised, and double-blind study aimed to compare the quality of recovery (Questionnaire QoR-40) of patients undergoing laparoscopic cholecystectomy under low-pressure and standard-pressure pneumoperitoneum. We tested the hypothesis that low pneumoperitoneum pressure enhances the quality of recovery following LC. METHODS: Eighty patients who underwent elective laparoscopic cholecystectomy were randomly divided into two groups, a low-pressure (10 mm Hg) pneumoperitoneum group and a standard-pressure (14 mm Hg) pneumoperitoneum group. For all participants, the value of the insufflation pressure was kept hidden and only the nurse responsible for the operating room was aware of it. Deep neuromuscular blockade was induced for all cases [train-of-four (TOF) = 0; post-tetanic count (PTC) > 0]. The quality of recovery was assessed on the morning of first post-operative day. RESULTS: No difference was found in either total score or in its different dimensions according to the QoR-40 questionnaire. The patients in the low-pressure pneumoperitoneum group experienced more pain during forced coughing measured at 4 hours (median difference [95% CI], 1 [0-2]; P = .030), 8 hours (1 [0-2]; P = .030) and 12 hours (0 [0-1] P = .025) after discharge from the post-anaesthesia care unit, when compared with those in the standard-pressure pneumoperitoneum group. CONCLUSION: We thus conclude that the use of low-pressure pneumoperitoneum during elective laparoscopic cholecystectomy does not improve the quality of recovery.

Identification of flavonoid-3-O-glycosides from leaves of Casearia arborea (Salicaceae) by UHPLC-DAD-ESI-HRMS/MS combined with molecular networking and NMR.

INTRODUCTION: Casearia is an essential source of cytotoxic highly oxidised clerodane diterpenes, in addition to phenolics, flavonoids, and glycoside derivatives. Here we identify flavonoid-3-O-glycoside derivatives in the ethyl acetate (EtOAc) fraction of the methanolic extract from leaves C. arborea leaves. OBJECTIVE: To characterise the EtOAc phase from the methanolic extract of C. arborea leaves using ultra-high-performance liquid chromatography diode array detector high-resolution tandem mass spectrometry (UHPLC-DAD-HRMS/MS) and molecular networking-based dereplication. Methodology We identified compounds not annotated in the GNPS platform by co-injection of standards in HPLC-DAD or by isolation and characterisation of the metabolites using nuclear magnetic resonance (NMR) spectroscopy. A workflow on the GNPS platform aided the organisation of spectral data and dereplication by annotations. We subjected the EtOAc phase to HPLC-DAD analysis using standard compound co-injection to corroborate the GNPS annotations. We isolated unidentified compounds with semi-preparative HPLC-DAD for structural identification using NMR. RESULTS: We annotated a molecular family of flavonoid-3-O-glycosides in the molecular networking created using the GNPS platform. These included avicularin, cacticin, isoquercitrin, quercitrin, rutin, and a quercetin-3-O-pentoside cluster. We confirmed the annotations with standard compounds using HPLC-DAD co-injection analysis, besides identifying quercetin-3-O-robinobioside and kaempferol. We isolated three flavonoid-3-O-pentosides and characterised them using one- and two-dimensional NMR; we identified them as reynoutrin, guaijaverin, and avicularin. CONCLUSION: This work describes the isolation of kaempferol and nine known flavonoid-3-O-glycosides from the polar fraction of the methanolic extract (EtOAc) from C. arborea leaves using molecular networking to guide the chromatographic procedures. We identified eight compounds for the first time in Casearia that amplify and reinforce the genus' chemotaxonomy with the presence of glycosylated flavonoids.

Human-facilitated dispersal of the Gulf toadfish Opsanus beta (Goode & Bean, 1880) in the Guaratuba Bay, south-eastern Brazil.

Opsanus beta is endemic to the Gulf of Mexico and has recently been introduced to the Brazilian coast; probably the introduction is via ballast water and/or oil rigs. In this study, the presence of the species is recorded for the first time in Guaratuba Bay, on the southern coast of Brazil. In this region there are no port terminals, which suggests that O. beta used a different mode of human-facilitated transport to colonize Guaratuba Bay.

Identification and Recent Approaches for Evaluation, Operative Counseling, and Management in Patients With Freeman-Burian Syndrome: Principles for Global Treatment.

For many, the experience of a complex craniofacial malformation condition, such as Freeman-Burian syndrome (FBS), formerly Freeman-Sheldon syndrome, is deeply distressing. There are few references in the literature addressing initial evaluation and operative counseling for FBS, and guidance is absent. Two major outcomes of FBS are explored, namely diagnostic accuracy and therapeutic result, to identify factors influencing optimal clinical care in (1) diagnosis, (2) evaluation, (3) general and craniofacial operative counseling, and (4) craniofacial management.PubMed searches have yielded 15 results describing craniofacial surgery in FBS and 29 manuscripts describing psychosocial aspects of surgery and patient and family counseling and education in other non-intellectually impairing craniofacial malformation conditions. Research in this area of scholarship is plagued by problems, especially considerable knowledge gaps and an absence of study data for operative outcomes. As a result, the literature remains unsettled, though our experience presents a much more clear picture of the clinical reality for this challenging patient population. While many challenges and limitations to treatment are present, much can be done to afford these patients a good and productive quality of life through operative intervention and longitudinal psychosocial support.

Modulation of the antibiotic activity against multidrug resistant strains of coumarins isolated from Rutaceae species.

The first occurrences and dissemination of resistant microorganisms led to the inefficacy of many antibiotics, available in the market nowadays, therefore, the search for new substances with antimicrobial activity from natural sources has gained a great importance. The purpose of this work is to evaluate the antibacterial activity and modulation of drug resistance in Staphylococcus aureus by coumarins such as bergapten, xantotoxin, isopimpinellin and imperatorin obtained from two Rutaceae species (Metrodorea mollis and Pilocarpus spicatus). The antimicrobial activity was assessed based on the minimum inhibitory concentration (MIC), using the microdilution method. The MIC was >256 g/mL for all coumarins tested. Regarding the modulation of drug resistance assay, the isopimpinellin reducted the MIC of erytromicin by 4 times, whereas imperatorin exhibited the best result, reducing the MIC of tetracycline (2 times), erytomicin (4 times) and norfloxacin (4 times). By reducing the MIC of ethidium bromide, the imperatorin is consider in fact, as a putative efflux pump inhibitor of bacteria.

Antileishmanial Activity and Immunomodulatory Effects of Tricin Isolated from Leaves of Casearia arborea (Salicaceae).

Bioactivity-guided fractionation of antileishmanial active extract from leaves of Casearia arborea led to isolation of three metabolites: tricin (1), 1',6'-di-O-ß-d-vanilloyl glucopyranoside (2) and vanillic acid (3). Compound 1 demonstrated the highest activity against the intracellular amastigotes of Leishmania infantum, with an IC50 value of 56 µm. Tricin (1) demonstrated selectivity in mammalian cells (SI > 7) and elicited immunomodulatory effect on host cells. The present work suggests that tricin modulated the respiratory burst of macrophages to a leishmanicidal state, contributing to the parasite elimination. Therefore, the natural compound tricin could be further explored in drug design studies for leishmaniasis treatment.

Strategic planning in Brazilian protected areas: Uses and adjustments.

Management plans for protected areas commonly use strategic planning tools in their drafting. It is proposed that the adequate use of the instruments of planning and management of protected areas can improve their strategic competitiveness, providing greater financial and administrative independence, enabling them to be economically sustainable organizations. This study evaluated the application of concepts and strategy formulation, strategy principles and competitiveness, organizational diagnosis, strategic maps, scenarios, and other strategic planning instruments used for conservation management in Brazil. 25 management plans of 25 different protected areas were selected and studied, with special attention to the indicators used in each plan. Results indicate that there is a high suitability for the application of SP tools to the universe of protected areas, although management plans did not take full advantage of these tools. We also found that the broader use of these tools did not guarantee greater managerial effectiveness. We suggest that other governance variables beyond planning strategies must be improved, to ensure a better performance of protected areas.

Surgical Approach, Findings, and Eight-Year Follow-Up in a Twenty-Nine Year Old Female With Freeman-Sheldon Syndrome Presenting With Blepharophimosis Causing Near-Complete Visual Obstruction.

The authors describe the surgical approach, findings, and 8-year follow-up in a 29-year-old woman, with severe Freeman-Sheldon syndrome, presenting with congenital blepharophimosis of both upper eyelids resulting in near-complete functional visual obstruction. To avoid possible Freeman-Sheldon syndrome-associated complications of malignant hyperthermia, difficult vascular access, and challenging endotracheal intubation, the surgery was completed under local anesthesia without sedation, and anatomical and functional correction was immediate and remained stable at 8-year follow-up. Unlike many congenital craniofacial syndromes, which frequently involve life-long impairments, important implications exist for plastic surgeons to facilitate opportunities for patients to overcome functional limitations.

The use of novel packing material for improving methane oxidation in biofilters.

The use of biofilters (working bed volume of 7.85 L) for the oxidation of CH4 at low concentrations (from 0.17%v/v to 3.63%v/v, typically in waste gas from anaerobic sewage treatment) was investigated and four empty bed residence times were tested (in min): 42.8, 29.5, 19.6, and 7.4. Mixtures of organic (composted leaves) and three non-organic materials (sponge-based material - SBM, blast furnace slag - BFS, and expanded vermiculite - ExpV) were used as packing media. Along 188 operational days after the steady state was reached (95 days for start-up), the CH4 mineralization decreased while the inlet loads gradually increased from 3.0 ± 0.8 gCH4 m(-3) h(-1) to 148.8 ± 4.4 gCH4 m(-3) h(-1). The biofilter packed with ExpV showed the best results, since the CH4 conversions decreased from 95.0 ± 5.0% to 12.7 ± 3.7% as a function of inlet concentration, compared to the other two biofilters (SBM and BFS) which showed CH4 conversions decreasing from 56.0 ± 5.4% to 3.5 ± 1.2% as a function of inlet concentration. The methanotrophic activity of biomass taken from ExpV biofilter was three times higher than the activity of biomass from the other two biofilters. Taken together, these results suggested that ExpV provides an attractive environment for microbial growth, besides the mechanical resistance provided to the whole packing media, showing the potential to its use in biofiltration of diffuse CH4 emissions.

Effects of different supplemental soya bean oil levels on the performance of prepubertal Saanen goats: Oestrogen and progesterone release.

The aim of this study was to investigate the effects of different levels of soya bean oil in the total diet on the growth rate, metabolic changes, and oestrogen and progesterone release in Saanen goats. After dietary adaptation, 21 prepubertal goats (weight of 29.12 ± 0.91 kg, 230 days old) were randomly distributed among three diets of D2: inclusion of 2% soya bean oil in the total diet; D3: basal diet - inclusion of 3% soya bean oil in the total diet; and D4: inclusion of 4% soya bean oil in the total diet. The basal diet (D3) was formulated to promote a daily gain of 0.140 kg. The goats were weighed, and their blood samples were collected weekly. Glucose, cholesterol, triglycerides, total protein, urea, non-esterified fatty acids, beta-hydroxybutyrate, oestrogen and progesterone in the plasma were measured. Prepubertal goats that were fed D4 exhibited a significantly lower dry matter intake, urea and cholesterol levels compared with the goats that were fed D2 and D3. Indeed, goats that were fed D4 displayed a significantly lower final weight than goats that were fed D2 and D3. In contrast, the inclusion of soya bean oil in the diet increased the progesterone and oestrogen concentrations, and goats that were fed D4 released a significantly higher concentration of progesterone than those that were fed D2 and D3. Furthermore, the percentage of goats with a progesterone level greater than 1 ng/ml (functional Corpus luteum) was significantly higher among the goats that were fed D3 and D4 than among those that were fed D2. In this study, although the inclusion of 4% soya bean oil in the diet decreased dry matter intake and growth rate, it increased progesterone concentration and the percentage of goats with a functional Corpus luteum, suggesting that the inclusion of soya bean oil accelerated puberty in prepubertal goats.

The enigma of the rise of angiosperms: can we untie the knot?

Multiple hypotheses have been put forward to explain the rise of angiosperms to ecological dominance following the Cretaceous. A unified scheme incorporating all these theories appears to be an inextricable knot of relationships, processes and plant traits. Here, we revisit these hypotheses, categorising them within frameworks based on plant carbon economy, resistance to climatic stresses, nutrient economy, biotic interactions and diversification. We maintain that the enigma remains unresolved partly because our current state of knowledge is a result of the fragmentary nature of palaeodata. This lack of palaeodata limits our ability to draw firm conclusions. Nonetheless, based on consistent results, some inferences may be drawn. Our results indicate that a complex multidriver hypothesis may be more suitable than any single-driver theory. We contend that plant carbon economy and diversification may have played an important role during the early stages of gymnosperms replacement by angiosperms in fertile tropical sites. Plant tolerance to climatic stresses, plant nutrition, biotic interactions and diversification may have played a role in later stages of angiosperm expansion within temperate and harsh environments. The angiosperm knot remains partly tied, but to unravel it entirely will only be feasible if new discoveries are made by scientific communities.

MicroRNA expression as risk biomarker of breast cancer metastasis: a pilot retrospective case-cohort study.

BACKGROUND: MicroRNAs (miRNAs) are small, non-coding RNA molecules involved in post-transcriptional gene regulation and have recently been shown to play a role in cancer metastasis. In solid tumors, especially breast cancer, alterations in miRNA expression contribute to cancer pathogenesis, including metastasis. Considering the emerging role of miRNAs in metastasis, the identification of predictive markers is necessary to further the understanding of stage-specific breast cancer development. This is a retrospective analysis that aimed to identify molecular biomarkers related to distant breast cancer metastasis development. METHODS: A retrospective case cohort study was performed in 64 breast cancer patients treated during the period from 1998-2001. The case group (n = 29) consisted of patients with a poor prognosis who presented with breast cancer recurrence or metastasis during follow up. The control group (n = 35) consisted of patients with a good prognosis who did not develop breast cancer recurrence or metastasis. These patient groups were stratified according to TNM clinical stage (CS) I, II and III, and the main clinical features of the patients were homogeneous. MicroRNA profiling was performed and biomarkers related to metastatic were identified independent of clinical stage. Finally, a hazard risk analysis of these biomarkers was performed to evaluate their relation to metastatic potential. RESULTS: MiRNA expression profiling identified several miRNAs that were both specific and shared across all clinical stages (p ≤ 0.05). Among these, we identified miRNAs previously associated with cell motility (let-7 family) and distant metastasis (hsa-miR-21). In addition, hsa-miR-494 and hsa-miR-21 were deregulated in metastatic cases of CSI and CSII. Furthermore, metastatic miRNAs shared across all clinical stages did not present high sensitivity and specificity when compared to specific-CS miRNAs. Between them, hsa-miR-183 was the most significative of CSII, which miRNAs combination for CSII (hsa-miR-494, hsa-miR-183 and hsa-miR-21) was significant and were a more effective risk marker compared to the single miRNAs. CONCLUSIONS: Women with metastatic breast cancer, especially CSII, presented up-regulated levels of miR-183, miR-494 and miR-21, which were associated with a poor prognosis. These miRNAs therefore represent new risk biomarkers of breast cancer metastasis and may be useful for future targeted therapies.

Nucleotide diversity based on phaseolin and iron reductase genes in common bean accessions of different geographical origins.

Discriminating genotypes within plant collections is imperative, and DNA sequence approaches for detecting single nucleotide polymorphisms (SNPs) have proved essential in any modern analysis of germplasm. By sequencing the α-Phs and PvFRO1 genes that, respectively, encode phaseolin and an iron reductase, we prospected for SNPs in exonic and intronic regions of both genes in a sample of 31 accessions of Phaseolus vulgaris from Mesoamerican and Andean gene pools, and one accession of Phaseolus lunatus, chosen as an outgroup. Sequence alignment showed 95 SNPs in α-Phs and 83 in PvFRO1, but diversity along the nucleotide sequences was not evenly distributed in both genes. Accessions from the same gene pool showed greater similarity than those from different gene pools, and the cluster patterns obtained in this study were consistent with the hierarchical organization into two P. vulgaris gene pools. The polymorphisms detected in the α-Phs gene allowed better discrimination among the accessions within each cluster than the PvFRO1 polymorphisms. Furthermore, some variations within exons changes amino acids in both predicted protein sequences. In an unprecedented result, the phaseolin-predicted amino acid variation allowed most of the accessions to be typified.

Impact of inocula and operating conditions on the microbial community structure of two anammox reactors.

The microbial community structure of the biomass selected in two distinctly inoculated anaerobic oxidation of ammonium (anammox) reactors was investigated and compared with the help of data obtained from 454-pyrosequencing analyses. The anammox reactors were operated for 550 days and seeded with different sludges: sediment from a constructed wetland (reactor I) and biomass from an aerated lagoon part of the oil-refinery wastewater treatment plant (reactor II). The anammox diversity in the inocula was evaluated by 16S rRNA gene-cloning analysis. The diversity of anammox bacteria was greater in the sludge from the oil-refinery (three of the five known genera of anammox were detected) than in the wetland sludge, in which only Candidatus Brocadia was observed. Pyrosequencing analysis demonstrated that the community enriched in both reactors had differing compositions despite the nearly similar operational conditions applied. The dominant phyla detected in both reactors were Proteobacteria, Chloroflexi, Planctomycetes, and Acidobacteria. The phylum Bacteroidetes, which is frequently observed in anammox reactors, was not detected. However, Acidobacteria and GN04 phyla were observed for the first time, suggesting their importance for this process. Our results suggest that, under similar operational conditions, anammox populations (Ca. Brocadia sinica and Ca. Brocadia sp. 40) were selected in both reactors despite the differences between the two initial inocula. Taken together, these results indicated that the type of inoculum and the culture conditions are key determinants of the general microbial composition of the biomass produced in the reactors. Operational conditions alone might play an important role in anammox selection.

Two new species of Hygronemobius Hebard, 1913 (Orthoptera, Grylloidea, Nemobiinae) from Brazilian Amazon.

Two new Neotropical species of Hygronemobius Hebard were described from Brazilian Amazon: Hygronemobius duckensis sp. nov. and Hygronemobius dialeucus sp. nov. Photographs of habitus, morphological characteristics and male genitalia were provided. Calling songs and spectrograms of the new species were characterized.

First record of the genera Luzarida Hebard, 1928 and Luzaridella Desutter-Grandcolas, 1992 (Orthoptera, Gryllidae, Phalangopsinae) from Brazil, including a new species and description of the female of Luzarida lata Gorochov, 2011.

Luzarida and Luzaridella are first recorded from Brazil. A new species of Luzaridella and the female of Luzarida lata is described from Central Amazon. Habitus, morphological characteristics, male and female genitalia photographs are provided. Calling song of Luzarida lata and Luzaridella sp. nov. are characterized.

Taxonomic revision of the Neotropical genus Argentinomyia Lynch-Arribálzaga, 1891 (Diptera: Syrphidae), with description of 16 new species.

The Neotropical flower fly genus Argentinomyia Lynch-Arribálzaga (Diptera: Syrphidae) is revised and rediagnosed. An updated key to the Neotropical genera of Bacchini and Melanostomini is provided. As a result of the ongoing systematic study of the genus, sixteen new species were discovered and described: Argentinomyia aurifacies Montoya & Thompson sp. nov. (Dominican Republic), Argentinomyia belmira Montoya & Wolff sp. nov. (Colombia), Argentinomyia humboldti Montoya & Wolff sp. nov. (Colombia and Ecuador), Argentinomyia ivani Montoya sp. nov. (Colombia), Argentinomyia jalcaensis Thompson & Montoya sp. nov. (Perú), Argentinomyia jamaicensis Montoya sp. nov. (Jamaica), Argentinomyia norrbomi Montoya sp. nov. (Brazil), Argentinomyia occidentalis Montoya & Wolff sp. nov. (Colombia), Argentinomyia plaumanni Thompson & Montoya sp. nov. (Brazil), Argentinomyia sagoti Montoya sp. nov. (Mexico), Argentinomyia serendipia Montoya sp. nov. (Colombia), Argentinomyia spinifemorata Montoya sp. nov. (Colombia), Argentinomyia taina Montoya & Thompson sp. nov. (Dominican Republic), Argentinomyia teresae Montoya sp. nov. (Colombia), Argentinomyia transversalis Montoya sp. nov. (Colombia and Bolivia) and Argentinomyia tropandeana Montoya sp. nov. (Colombia, Ecuador and Perú). Five new synonyms are proposed for four species: Melanostoma melanocerum (Williston, 1891) = Argentinomyia catabomba (Williston, 1891), Braziliana columbiana (Enderlein, 1935) = Argentinomyia fastigata (Fluke, 1945), Braziliana peruviana (Shannon, 1927), Braziliana thiemei (Enderlein, 1935) = Argentinomyia longicornis (Walker, 1836) and Rhysops funerea (Hull, 1949) = Argentinomyia nigrans (Fluke, 1945). Lectotypes are designated for the following names: Melanostoma catabombum Williston, 1891, Melanostoma crenulatum Williston, 1891, Melanostoma longicornis Williston, 1888, Melanostoma melanocerum Williston, 1891 and Pipiza longicornis Walker, 1836. Twenty-six species are redescribed and an updated key proposed for 41 out of the 47 species recognized as valid. Synonyms, descriptions, comparative diagnosis, high-definition color photographs of overall appearance, illustrations of the male genitalia as well as field photographs are provided. The known distribution ranges are mapped and the biogeographical affinity and endemism are discussed. Female genitalia are described for the first time for the genus. Argentinomyia berthae (Lima, 1946) is rediscovered and redescribed, including the designation of a neotype. The taxonomic status of Argentinomyia scitula (Williston, 1888) is considered doubtful and needs further study. Taxonomic notes are provided for Argentinomyia aenea (Willistoni, 1891) and A. huitepecensis Montoya, 2020. The high diversity, the biogeographical affinities, the noteworthy endemism patterns, new country records as well as the morphological variation evidenced in the present revision suggest that the genus is much more diverse than it appears, with many new species that undoubtedly remain to be described from unexplored areas of the Neotropics. Our study provides a thorough morphological assessment as well as the updated biogeographical distribution, which constitute a starting point to answer questions and propose hypotheses about the phylogenetic relationships, historical biogeography, diversification patterns and conservation of Argentinomyia in forthcoming contributions.