Diversity, distribution and extinction risk of native freshwater fishes of South Africa.

Extinction risk for 101 valid species and 18 unique genetic lineages of native freshwater fishes of South Africa was assessed in 2016 following the IUCN Red List criteria. An additional five species (three new species that were described and two species that were revalidated subsequent to the 2016 assessments) were assessed in the present study. A synthesis of the outcome of the assessments of the 106 valid species and 18 genetic lineages indicates that 45 (36%) of South Africa's freshwater fish taxa are threatened (7 Critically Endangered, 25 Endangered, 13 Vulnerable). Of the remaining taxa, 17 (14%) are listed as Near Threatened, 57 (46%) are Least Concern and five (4%) are Data Deficient. More than 60% of the endemic taxa are threatened. The Cape Fold Ecoregion has the highest proportion of threatened taxa (67%) due to the existence of a unique assemblage of narrow-range endemic species. Galaxias and Pseudobarbus have the highest number of highly threatened taxa as most of the species and lineages in these genera are classified as either CR or EN. Major threats to the native freshwater fishes of the country are invasive fish species, deterioration of water quality, impoundments and excessive water abstraction, land use changes and modification of riverine habitats. Immediate conservation efforts should focus on securing remnant populations of highly threatened taxa and preventing deterioration in threat status, because recovery is rare. Accurate delimitation of species boundaries, mapping their distribution ranges, improved knowledge of pressures and long-term monitoring of population trends need to be prioritised to generate credible data for the 2026 IUCN threat status assessments and designation of important fish areas as part of the National Freshwater Ecosystem Priority Areas (NFEPA) initiative.

Overprescription of Opioids Following Outpatient Anorectal Surgery: A Single-Institution Study.

BACKGROUND: Surgeons contribute to the opioid epidemic by overprescribing opioids for postoperative pain. Excess, unused opioids may be diverted for misuse/abuse. OBJECTIVE: This study aimed to characterize opioid prescribing and use among patients undergoing outpatient anorectal procedures and to assess the adequacy of postoperative pain management. DESIGN: This is a retrospective cohort study, prospective cross-sectional survey. SETTINGS: Patients were treated by colorectal surgeons in an academic medical center between January 2018 and September 2019. PATIENTS: Six hundred twenty-seven patients undergoing an outpatient anorectal procedure were included. MAIN OUTCOME MEASURES: The primary outcomes measured were the opioids prescribed at discharge, opioid prescription refills, patient-reported outcomes regarding opioid use, and the adequacy of postoperative pain management in terms of pain intensity and pain interference. Opioids were standardized to 5-mg oxycodone pills. Patient-reported outcomes were assessed by using previously validated instruments. RESULTS: The majority of patients underwent fistula surgery (n = 234) followed by examination under anesthesia (n = 183), hemorrhoidectomy (n = 131), incision and drainage (n = 51), and pilonidal excision (n = 28). Most patients received opioids (78% fistula, 49% examination under anesthesia, 87% hemorrhoidectomy, 71% incision and drainage, 96% pilonidal). Patients undergoing examination under anesthesia received the fewest opioid pills (median 10; range 3-50) followed by patients undergoing fistula surgery (median13, range 1-50), incision and drainage (median 15, range 3-120), pilonidal excisions (median 15, range 3-60), and hemorrhoidectomies (median 28, range 3-60). Regardless of procedure, the majority of patients used fewer than 5 opioid pills postoperatively. Patients undergoing pilonidal excisions had the largest number of excess unused pills (median 14, range 0-30) followed by patients undergoing fistula surgery and incision and drainage (median 7, ranges 0-30 and 5-17), hemorrhoidectomy (median 6, range 0-50), and examination under anesthesia (median 2, range 0-23). Whereas patients undergoing hemorrhoidectomy reported higher pain levels following discharge, most reported minimal interference with day-to-day activities due to pain regardless of the procedure performed. LIMITATIONS: The limitations of this study included recall bias and sample bias. CONCLUSIONS: The majority of patients do not need more than five to ten 5-mg oxycodone equivalents to achieve adequate pain management after outpatient anorectal surgical procedures. See Video Abstract at http://links.lww.com/DCR/B347. EXCESO DE PRESCRIPCIÓN DE OPIOIDES DESPUÉS DE UNA CIRUGÍA ANORRECTAL AMBULATORIA: UN ESTUDIO DE UNA SOLA INSTITUCIÓN: Cirujanos contribuyen a la epidemia de opioides al recetar en exceso opioides para el dolor postoperatorio. El exceso de opioides no utilizados puede ser desviado por para mal uso o abuso.Caracterizar la prescripción y el uso de opioides entre pacientes sometidos a procedimientos anorrectales ambulatorios y evaluar la efectividad del tratamiento del dolor postoperatorio.Estudio de cohorte retrospectivo, encuesta transversal prospectiva.pacientes tratados por cirujanos colorrectales en un centro médico académico entre enero de 2018 y septiembre de 2019.se incluyeron 627 pacientes que se sometieron a un procedimiento anorrectal ambulatorio.Opioides recetados al alta, reabastecimientos de prescripción de opioides, resultados informados por el paciente con respecto al uso de opioides y efectividad del manejo del dolor postoperatorio en términos de intensidad del dolor y trastornos secundarios a dolor. Los opioides se estandarizaron con píldoras de oxicodona de 5 mg. Los resultados informados por los pacientes se evaluaron utilizando instrumentos previamente validados.La mayoría de los pacientes fueron sometidos a cirugía de fístula (n = 234) seguida de un examen bajo anestesia (EUA; n = 183), hemorroidectomía (n = 131), incisión y drenaje (I&D) (n = 51) y escisión pilonidal (n = 28). La mayoría de los pacientes recibieron opioides (78% fístula, 49% EUA, 87% hemorroidectomía, 71% I&D, 96% pilonidal). Las EUA recibieron la menor cantidad de píldoras opioides (mediana 10, rango 3-50) seguidas de fístula (mediana 13, rango 1-50), I y D (mediana 15, rango 3-120), pilonidales (mediana 15, rango 3-60) y hemorroides. (mediana 28, rango 3-60). Independientemente del procedimiento, la mayoría de los pacientes usaron menos de cinco píldoras opioides después de la operación. Los pacientes pilonidales tuvieron el mayor número de píldoras no utilizadas en exceso (mediana 14, rango 0-30) seguido de fístula e I&D (mediana 7, rangos 0-30 y 5-17, respectivamente), hemorroidectomía (mediana 6, rango 0-50) y EUA (mediana 2, rango 0-23). Si bien los pacientes con hemorroidectomía informaron niveles de dolor más altos después del alta, la mayoría de pacientes informaron un mínimo de interferencia con las actividades diarias debido al dolor, independientemente del procedimiento realizado.Sesgo de recuerdo autoinformado, sesgo de muestra.La mayoría de los pacientes no necesitan más de cinco a diez equivalentes de oxicodona de 5 mg para lograr un manejo adecuado del dolor después de procedimientos quirúrgicos anorrectales ambulatorios. Consulte Video Resumen en http://links.lww.com/DCR/B347. (Traducción-Dr. Adrian Ortega).

Multiple colonisations of the Lake Malawi catchment by the genus Opsaridium (Teleostei: Cyprinidae).

It has been proposed that the fish faunas of African rivers assemble through multiple colonisation events, while lake faunas form additionally through intralacustine speciation. While this pattern has been established for many lineages, most notably cichlids, there are opportunities to further investigate the concept using phylogenies of congeneric endemic species within ancient lake catchments. The Lake Malawi catchment contains three river-spawning cyprinids of the genus Opsaridium, two of which are endemic. These species differ in body size, migratory behaviour and habitat use, but it has never previously been tested if these represent a monophyletic radiation, or have instead colonised the lake independently. We placed these species in a broader phylogeny of Opsaridium and the related genus Raiamas, including all known species from the river systems surrounding Lake Malawi. Our results suggest that each of the species has independently colonised the lake catchment, with all three taxa having well-defined sister taxa outside of the lake, and all sharing a common ancestor ∼14.9million years ago, before the Lake Malawi basin started to form ∼8.6million years ago. Additionally, the results strongly support previous observations that Opsaridium is not a monophyletic group, but instead contains Raiamas from the Congo drainage. Together these results are supportive of the concept that river fish faunas within African catchments are primarily assembled through a process of accumulation from independent origins, rather than within-catchment speciation and adaptive radiation. In light of these results we also suggest there is scope for a re-evaluation of systematics of both Opsaridium and Raiamas.

Direct surface analysis coupled to high-resolution mass spectrometry reveals heterogeneous composition of the cuticle of Hibiscus trionum petals.

Plant cuticle, which is the outermost layer covering the aerial parts of all plants including petals and leaves, can present a wide range of patterns that, combined with cell shape, can generate unique physical, mechanical, or optical properties. For example, arrays of regularly spaced nanoridges have been found on the dark (anthocyanin-rich) portion at the base of the petals of Hibiscus trionum. Those ridges act as a diffraction grating, producing an iridescent effect. Because the surface of the distal white region of the petals is smooth and noniridescent, a selective chemical characterization of the surface of the petals on different portions (i.e., ridged vs smooth) is needed to understand whether distinct cuticular patterns correlate with distinct chemical compositions of the cuticle. In the present study, a rapid screening method has been developed for the direct surface analysis of Hibiscus trionum petals using liquid extraction surface analysis (LESA) coupled with high-resolution mass spectrometry. The optimized method was used to characterize a wide range of plant metabolites and cuticle monomers on the upper (adaxial) surface of the petals on both the white/smooth and anthocyanic/ridged regions, and on the lower (abaxial) surface, which is entirely smooth. The main components detected on the surface of the petals are low-molecular-weight organic acids, sugars, and flavonoids. The ridged portion on the upper surface of the petal is enriched in long-chain fatty acids, which are constituents of the wax fraction of the cuticle. These compounds were not detected on the white/smooth region of the upper petal surface or on the smooth lower surface.

Total synthesis of chloptosin: a dimeric cyclohexapeptide.

Here we describe in full our investigations into the synthesis of the dimeric cyclohexapeptide chloptosin in 17 linear steps. Particularly, this work features an organocatalytic tandem process for the synthesis of the embedded piperazic acids, in which a differentially protected azodicarboxylate is used together with pyrrolidinyl tetrazole as the catalyst. The central biaryl bond is being formed by Stille coupling of two sterically demanding ortho-chloropyrroloindole fragments. The inherent flexibility of the synthetic strategy proved beneficial as the route could be adjusted smoothly during the progression of the synthesis programme.

Four new species of Serranochromis (Teleostei: Cichlidae) from the Cuanza and Okavango river systems in Angola, including a preliminary key for the genus.

The present study describes Serranochromis alvum n. sp., Serranochromis swartzi n. sp., Serranochromis cuanza n. sp., and Serranochromis cacuchi n. sp. from Angolan tributaries of the Cuanza and Okavango systems in Angola. The presence of four or five scale rows between the posterior margin of the orbit and the ascending arm of the preoperculum, the presence of widely set unicuspid teeth on the jaws, widely separated gill rakers, and anal fins with egg ocelli place these four species in Serranochromis. The Serranochromis described herein are distinguishable based on a combination of morphological and meristic characters, as well as pigmentation patterns. The interorbital width (14.3-15.9 % HL) of S. alvum is narrower than that of S. swartzi (17.6-19.8), S. cuanza (16.3-18.0), and S. cacuchi (20.0-21.7). Moreover, the interorbital width of S. cacuchi is greater than the other three described species. Serranochromis swartzi has a smaller preorbital depth (16.2-18.9 % HL) and snout length (29.6-31.9 % HL) than Serranochromis cuanza (PD 19.1-22.2, SNL 35.2-39.6 % HL). Serranochromis alvum is known only from the type locality at Cuito-Cuanavale at the junction of the Cuito and Cuanavale rivers, tributary to the Okavango River in Angola. Serranochromis swartzi is known only from the type locality in the Cuanza River, Angola. Serranochromis cuanza is restricted to the Cuanza River, below Capanda Dam, Angola, while S. cacuchi is known only from the Cacuchi River, a tributary of the Cuchi-Cubango River in Angola. The limited distribution of all four species and the absence of many congeners suggest, that in addition to previous studies that invoked a lacustrine speciation model, vicariance through drainage isolation seems to have played an important role in driving speciation in this group. The minimum polygon clusters that are formed when the first principal components of the meristic data are plotted against the second sheared principal components of the morphometric data show separation of the four new species.

Re-elevation to species level and redescription of Serranochromis jallae and Serranochromis robustus (Teleostei: Cichlidae).

Serranochromis robustus robustus from Lake Malawi and Serranochromis robustus jallae from Zambia were compared using morphological data. We re-elevated S. robustus jallae to species based on the following. Serranochromis robustus generally has a longer lower jaw (50.7-59.6% HL) than S. jallae (49.2-52.7% HL). Serranochromis robustus is not as deep-bodied as S. jallae as evidenced by the distance between the posterior insertion of the dorsal fin and the posterior insertion of the anal fin (13.4-15.1% SL in S. robustus vs. 14.9-18.4% SL in S. jallae). Additionally, S. robustus has a narrower least caudal peduncle depth (10.9-12.8% SL) than S. jallae (11.3-14.2% SL); the least caudal peduncle depth of all S. robustus was less than 12.8% SL while, except for the smallest specimen of S. jallae (88.1 mm SL), the least caudal peduncle depth was greater than 13.2% SL. Adults in breeding color of Serranochromis robustus are blue/green laterally, while adults in breeding color of S. jallae are yellow/green laterally. The marginal bands on the dorsal and caudal fins of S. jallae are bright orange in specimens from the Okavango River system and creamy yellow in Upper Zambezi specimens. In S. robustus, there is a yellow marginal band on the dorsal fin.

Phylogeny and biogeography of the genus Pseudobarbus (Cyprinidae): shedding light on the drainage history of rivers associated with the Cape Floristic Region.

Relationships among the historically isolated lineages of Pseudobarbus were reconstructed using molecular and morphological data. Contradictions between the molecular and morphological phylogenies suggest convergent evolution and homoplasy in some morphological characters. The earliest divergence in Pseudobarbus was between P. quathlambae in Lesotho and the rest of the genus associated with the Cape Foristic Region in South Africa. A close relationship between P. phlegethon from the Olifants River system on the west coast of South Africa and a lineage of P. afer from small river systems in Afrotemperate Forests on the south coast, can only be explained through previous occurrence and subsequent extinction of ancestral populations in the Gourits River system. Several river systems had confluences before reaching lower sea levels, most notably during the last glacial maximum about 18,000 years ago, explaining closely related populations across different river systems. Mainly river capture explains shared lineages across river systems that did not share a common confluence during lower sea levels.

Crystal structure and growth mechanism of unusually long fullerene (C60) nanowires.

Exceptionally long C60 nanowires, with a length to width aspect ratio as large as 3000, are grown from a 1,2,4-trimethylbenzene solution of C60. They have been formed to possess a highly unusual morphology, with each nanowire being composed of two nanobelts joined along the growth direction to give a V-shaped cross section. The crystal structure of these nanowires is found to be orthorhombic, with the unit cell dimensions of a = 10.2 A, b = 20.5 A, and c = 25.6 A. Structural and compositional analyses enable us to explain the observed geometry with an anisotropic molecular packing mechanism that has not been observed previously in C60 crystal studies. The nanowires have been observed to be able to transform into carbon nanofibers following high-temperature treatment, but the original V-shaped morphology can be kept unchanged in the transition. A model for the nanowire morphology based upon the solvent-C60 interactions and preferential growth directions is proposed, and potentially it could be extended for use to grow different types of fullerene nanowires.

A review of the Pseudobarbus afer (Peters, 1864) species complex (Teleostei, Cyprinidae) in the eastern Cape Fold Ecoregion of South Africa.

The Eastern Cape redfin, Pseudobarbus afer, has long been considered to be a single widespread and variable species occurring in multiple isolated river systems in the Cape Fold Ecoregion (CFE) at the southern tip of Africa. Mitochondrial cytochrome b and control region sequence data of individuals from populations currently assigned to Pseudobarbus afer across the species' distribution range revealed existence of four deeply divergent taxonomic units: (i) the Mandela lineage confined to the Sundays, Swartkops and Baakens river systems, (ii) the Krom lineage endemic to the Krom River system, (iii) the St Francis lineage occurring in the Gamtoos and adjacent river systems, and (iv) the Forest lineage occurring in several coastal river systems from the Tsitsikamma to the Klein Brak River system. The Forest lineage is closely related to Pseudobarbus phlegethon from the Olifants River system on the west coast of South Africa, suggesting that it does not belong to Pseudobarbus afer s.l. Herein we focus on the three lineages within the Pseudobarbus afer s.l. complex and provide new diagnosis for Pseudobarbus afer s.s (Mandela lineage), revalidate Pseudobarbus senticeps (Krom lineage) as a distinct species, and describe a new species Pseudobarbus swartzi (St Francis lineage). The three species exhibit subtle differences, which explains why they were previously considered to represent a single variable and widespread species. Pseudobarbus senticeps differs from both Pseudobarbus afer and Pseudobarbus swartzi by having fewer (i.e. larger) scales (25-33, mode 29 lateral line scale series; 10-12, mode 11 circumpeduncular scales) and presence of a lateral stripe which terminates in a conspicuous triangular blotch at the base of the caudal fin. Long barbels which reach or surpass the vertical through the posterior edge of the eye further separate Pseudobarbus senticeps from Pseudobarbus afer s.s. which possesses simple short barbels which do not reach the vertical through the posterior margin of the eye. Pseudobarbus afer s.s differs from Pseudobarbus swartzisp. n. by possession of fewer scale rows along the lateral line (29-35, mode 32 vs 34-37, mode 36 in Pseudobarbus swartzi), fewer scales around the caudal peduncle (12-16, mode 12 vs 13-17, mode 16 in Pseudobarbus swartzi) and a distinct mesh or net-like pigmentation pattern on latero-ventral scales.

Structure elucidation of a novel family of mycolactone toxins from the frog pathogen Mycobacterium sp. MU128FXT by mass spectrometry.

Structures are proposed, based on LC-ion trap MSn analysis and high-resolution FTICR MS/MS analysis, for a novel family of mycolactone toxins isolated from the frog pathogen MU128FXT and differing from those produced by the human pathogen M. ulcerans MUAgy99 in having an altered polyketide side chain.

Hydrogen/deuterium exchange of hydrophobic peptides in model membranes by electrospray ionization mass spectrometry.

We demonstrate here that the hydrogen/deuterium solvent exchange (HDX) properties of the transmembrane fragment of the M2 protein of Influenza A (M2-TM) incorporated into lipid vesicles or detergent micelles can be studied with straightforward electrospray (ESI) and nanospray mass spectrometry (MS) configurations provided that key factors, including sample preparation techniques, are optimized. Small unilamellar vesicle preparations were obtained by solubilizing dimyristoyl phosphatidylcholine (DMPC) and the M2-TM peptide in aqueous solution with n-octyl-beta-D-glycopyranoside, followed by dialysis to remove the detergent. Electron microscopy experiments revealed that subsequent concentration by centrifugation introduced large multilamellar aggregates that were not compatible with ESI-MS. By contrast, a lyophilization-based concentration procedure, followed by thawing above the liquid crystal transition temperature of the lipid component, maintained the liposome size profile and yielded excellent ion fluxes in both ESI-MS and nano-ESI-MS. Using these methods the global HDX profile of M2-TM in aqueous DMPC vesicles was compared with that in methanol, demonstrating that several amide sites were protected from exchange by the lipid membrane. We also show that hydrophobic peptides can be detected by ESI-MS in the presence of a large molar excess of the detergent Triton X-100. The rate of HDX of M2-TM in Triton X-100 micelles was faster than that in DMPC vesicles but slower than when the peptide had been denatured in methanol. These results indicate that the accessibility of backbone amide sites to the solvent can be profoundly affected by membrane protein structure and dynamics, as well as the properties of model bilayer systems.

A new species of redfin (Teleostei, Cyprinidae, Pseudobarbus) from the Verlorenvlei River system, South Africa.

Pseudobarbusverloreni, a new species, is described from material collected in the Verlorenvlei River system on the west coast of South Africa. It differs from its congeners (except Pseudobarbusskeltoni, Pseudobarbusburchelli, and Pseudobarbusburgi) by the presence of two pairs of oral barbels. Pseudobarbusverloreni sp. n. can be distinguished from the three currently described double barbeled Pseudobarbus species by the following combination of characters: pigment pattern, generally deeper body relative to standard length, a longer intestine associated with the deeper body form, shorter snout relative to head length, and much shorter anterior barbels relative to head length. The new species is distinguished from Pseudobarbusburgi in the neighbouring Berg River system by its longer head and longer pre-dorsal length. It seems as if Pseudobarbusverloreni sp. n. has been extirpated from the Langvlei River system and face several threats to its survival in the Verlorenvlei River system.

Biomechanical responses of a pig head under blast loading: a computational simulation.

A series of computational studies were performed to investigate the biomechanical responses of the pig head under a specific shock tube environment. A finite element model of the head of a 50-kg Yorkshire pig was developed with sufficient details, based on the Lagrangian formulation, and a shock tube model was developed using the multimaterial arbitrary Lagrangian-Eulerian (MMALE) approach. These two models were integrated and a fluid/solid coupling algorithm was used to simulate the interaction of the shock wave with the pig's head. The finite element model-predicted incident and intracranial pressure traces were in reasonable agreement with those obtained experimentally. Using the verified numerical model of the shock tube and pig head, further investigations were carried out to study the spatial and temporal distributions of pressure, shear stress, and principal strain within the head. Pressure enhancement was found in the skull, which is believed to be caused by shock wave reflection at the interface of the materials with distinct wave impedances. Brain tissue has a shock attenuation effect and larger pressures were observed in the frontal and occipital regions, suggesting a greater possibility of coup and contrecoup contusion. Shear stresses in the brain and deflection in the skull remained at a low level. Higher principal strains were observed in the brain near the foramen magnum, suggesting that there is a greater chance of cellular or vascular injuries in the brainstem region.

Cryptic diversity of African tigerfish (genus Hydrocynus) reveals palaeogeographic signatures of linked neogene geotectonic events.

The geobiotic history of landscapes can exhibit controls by tectonics over biotic evolution. This causal relationship positions ecologically specialized species as biotic indicators to decipher details of landscape evolution. Phylogeographic statistics that reconstruct spatio-temporal details of evolutionary histories of aquatic species, including fishes, can reveal key events of drainage evolution, notably where geochronological resolution is insufficient. Where geochronological resolution is insufficient, phylogeographic statistics that reconstruct spatio-temporal details of evolutionary histories of aquatic species, notably fishes, can reveal key events of drainage evolution. This study evaluates paleo-environmental causes of mitochondrial DNA (mtDNA) based phylogeographic records of tigerfishes, genus Hydrocynus, in order to reconstruct their evolutionary history in relation to landscape evolution across Africa. Strong geographical structuring in a cytochrome b (cyt-b) gene phylogeny confirms the established morphological diversity of Hydrocynus and reveals the existence of five previously unknown lineages, with Hydrocynus tanzaniae sister to a clade comprising three previously unknown lineages (Groups B, C and D) and H. vittatus. The dated phylogeny constrains the principal cladogenic events that have structured Hydrocynus diversity from the late Miocene to the Plio-Pleistocene (ca. 0-16 Ma). Phylogeographic tests reveal that the diversity and distribution of Hydrocynus reflects a complex history of vicariance and dispersals, whereby range expansions in particular species testify to changes to drainage basins. Principal divergence events in Hydrocynus have interfaced closely with evolving drainage systems across tropical Africa. Tigerfish evolution is attributed to dominant control by pulses of geotectonism across the African plate. Phylogenetic relationships and divergence estimates among the ten mtDNA lineages illustrates where and when local tectonic events modified Africa's Neogene drainage. Haplotypes shared amongst extant Hydrocynus populations across northern Africa testify to recent dispersals that were facilitated by late Neogene connections across the Nilo-Sahelian drainage. These events in tigerfish evolution concur broadly with available geological evidence and reveal prominent control by the African Rift System, evident in the formative events archived in phylogeographic records of tigerfish.