Evidence of chromosome fusion in Gymnotus sylvius Albert & Fernandes-Matoli, 1999 (Teleostei: Gymnotiformes) detected by telomeric probes and R-banding

Gymnotus cf. carapo and Gynznotus sylvius are two fish species inhabiting the Upper Parana River Basin, presenting respectively 2n =54 and 2n = 40 chromosomes. In the present cytogenetic analysis, R-banding and telomere-sequence hybridization were carried out in order to determine the possible relationship between the karyotipes of these two species. Incorporation bands (R-bands) obtained for the two species allowed the identification of chromosome similarities, showing to be an usefull alternative to the G-banding methods, which fail in producing satisfying results in most of analyzed fish species. This approach, associated with the hybridization of telomeric sequences, permited to identify chromosomal rearrangements that could be used as indicators of karyotypic evolution within the group. In the present case, telomeric sequences were detected in the centromeric region of two metacentric chromosome pairs of Gymnotus sylvius. The results obtained after hybridization with the telomere sequences, coupled with the chromosome homeologies detected by R-banding, showed that G. cf carapo and G. sylvius should present a common ancestor, and this may also be corroborated by the similarities found in three chromosome pairs, that seem to have been conserved during the evolution of the two species. Based on the data here presented we propose that G. sylvius may have undergone a recent process of chromosome fusion that resulted in the diminution of its chromosome number.

A new vision of the origin and the oocyte development in the Ostariophysi applied to Gymnotus sylvius (Teleostei: Gymnotiformes)

Tendo por base os novos conhecimentos oriundos de recentes estudos com Perciformes marinho, a origem e o desenvolvimento dos oócitos no Ostariophysi Gymnotus sylvius são aqui descritos. da mesma maneira que ocorre nos Perciformes, em Gymnotus sylvius as oogônias são encontradas no epitélio germinativo que margeia as lamelas ovígeras. No início da foliculogênese, a proliferação das oogônias e sua entrada em meiose dão origem a ninhos de células germinativas que se projetam em direção ao estroma ovariano, a partir do epitélio germinativo. Os ninhos e o epitélio germinativo são suportados pela mesma membrana basal que os separa do estroma. Coincidindo com a paralisação da meiose os oócitos, presentes nos ninhos, são separados uns dos outros por processos citoplasmáticos das células pré-foliculares. As células pré-foliculares derivam do epitélio germinativo sendo, portanto, inicialmente células epiteliais. Durante a foliculogênese, ao mesmo tempo em que envolvem os oócitos individualizando-os, as células pré-foliculares sintetizam a membrana basal ao seu redor. Os oócitos entram em crescimento primário ainda dentro dos ninhos. Ao término da foliculogênese, o oócito e as células foliculares que compõem o folículo são circundados pela membrana basal. O folículo permanece conectado ao epitélio germinativo uma vez que ambos compartilham uma porção comum da membrana basal. Células oriundas do estroma circundam o folículo ovariano exceto na região de compartilhamento da membrana basal formando a teca. O folículo, a membrana basal e a teca formam o complexo folicular. O desenvolvimento do oócito ocorre dentro do complexo folicular e compreende os estágios de crescimento primário e secundário, maturação e ovulação. Os alvéolos corticais surgem no ooplasma momentos antes do início do crescimento secundário ou estágio vitelogênico que tem início com a deposição de vitelo, progride até o oócito esteja completamente desenvolvido e o ooplasma preenchido pelos glóbulos de vitelo. A maturação é caracterizada pela migração do núcleo ou vesícula germinativa, pela quebra da vesícula germinativa, ou seja, pela fragmentação do envoltório nuclear e, retomada da meiose. Na ovulação o ovo é liberado do complexo folicular para o lúmen ovariano. em comparação com os Perciformes marinhos com ovos pelágicos, o desenvolvimento oocitário em Gymnotus sylvius tem menos etapas dentro dos estágios de desenvolvimento, sendo as duas mais notáveis delas as ausências da formação das gotas de lipídio durante os crescimentos primário e secundário (e a consequente fusão das gotas para formar um único glóbulo de lipídio durante a maturação) e, a hidrólise do vitelo antecedendo a ovulação.

X1X1X2X2/X1X2Y sex chromosome systems in the Neotropical Gymnotiformes electric fish of the genus Brachyhypopomus

Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The ₁X₁X₂X₂/X₁X₂Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X₁X₁X₂X₂/X₁X₂Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B. n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X₁X₁X₂X₂/X₁X₂Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X₁X₁X₂X₂/X₁X₂Y system may represent sex chromosomes turnover events in Gymnotiformes.

Complex sex chromosome system in Eigenmannia sp. (Pisces, Gymnotiformes)

Chromosomes of Eigenmannia sp. (7 males and 15 females) collected from the Tietê River in Botucatu (SP, Brazil) were examined from gill, kidney and testicular cells. The diploid chromosome number in males was 2n=31 and in females, 2n=32. In both sexes the number of chromosomal arms was 40. The difference in diploid number was due to the fusion of two acrocentrics. Mitotic and meiotic studies suggested that one of the fused acrocentrics was the Y chromosome. The sex-determining mechanism in Eigenmannia sp. could therefore be XX, AA in the female and X, \-YA A in the males. One of the males presented 2n=30 chromosomes due to the occurrence of another fusion of acrocentrics. C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics. However, small metacentrics were C-band negative. The YA chromosome is C-band negative except for a small amount of heterochromatin in the centromeric region. The nucleolar organizer region as identified by Ag-staining is present in the interstitial region of chromosome pair No. 10. © 1984 Dr W. Junk Publishers.

Effect of bone graft type on fusion rates following endoscopic anterior scoliosis correction

Bone graft is generally considered fundamental in achieving solid fusion in scoliosis correction and pseudarthrosis following instrumentation may predispose to implant failure. In endoscopic anterior-instrumented scoliosis surgery, autologous rib or iliac crest graft has been utilised traditionally but both techniques increase operative duration and cause donor site morbidity. Allograft bone and bone- morphogenetic-protein alternatives may improve fusion rates but this remains controversial. This study's objective was to compare two-year postoperative fusion rates in a series of patients who underwent endoscopic anterior instrumentation for thoracic scoliosis utilising various bone graft types. Significantly better rates of fusion occurred in endoscopic anterior instrumented scoliosis correction using femoral allograft compared to autologous rib-heads and iliac crest graft. This may be partly explained by the difficulty obtaining sufficient quantities of autologous graft. Lower fusion rates in the autologous graft group appeared to predispose to rod fracture although the clinical consequence of implant failure is uncertain.

Improved maritime target tracker using colour fusion

Searching for humans lost in vast stretches of ocean has always been a difficult task. This paper investigates a machine vision system that addresses this problem by exploiting the useful properties of alternate colour spaces. In particular, the paper investigates the fusion of colour information from the HSV, RGB, YCbCr and YIQ colour spaces within the emission matrix of a Hidden Markov Model tracker to enhance video based maritime target detection. The system has shown promising results. The paper also identifies challenges still needing to be met.

The effect of bone graft type on fusion rates following anterior thoracoscopic scoliosis correction

Bone graft is generally considered fundamental in achieving solid fusion in scoliosis correction and pseudarthrosis following instrumentation may predispose to implant failure. In thoracoscopic anterior-instrumented scoliosis surgery, autologous rib or iliac crest graft has been utilised traditionally but both techniques increase operative duration and cause donor site morbidity. Allograft bone and bone morphogenetic protein (BMP) alternatives may improve fusion rates but this remains controversial. This study's objective was to compare two-year postoperative fusion rates in a series of patients who underwent thoracoscopic anterior instrumentation for thoracic scoliosis utilising various bone graft types.

Fusion of in-vehicle sensor data to develop Intelligent Driver Training System (IDTS)

The over represented number of novice drivers involved in crashes is alarming. Driver training is one of the interventions aimed at mitigating the number of crashes that involve young drivers. To our knowledge, Advanced Driver Assistance Systems (ADAS) have never been comprehensively used in designing an intelligent driver training system. Currently, there is a need to develop and evaluate ADAS that could assess driving competencies. The aim is to develop an unsupervised system called Intelligent Driver Training System (IDTS) that analyzes crash risks in a given driving situation. In order to design a comprehensive IDTS, data is collected from the Driver, Vehicle and Environment (DVE), synchronized and analyzed. The first implementation phase of this intelligent driver training system deals with synchronizing multiple variables acquired from DVE. RTMaps is used to collect and synchronize data like GPS, vehicle dynamics and driver head movement. After the data synchronization, maneuvers are segmented out as right turn, left turn and overtake. Each maneuver is composed of several individual tasks that are necessary to be performed in a sequential manner. This paper focuses on turn maneuvers. Some of the tasks required in the analysis of ‘turn’ maneuver are: detect the start and end of the turn, detect the indicator status change, check if the indicator was turned on within a safe distance and check the lane keeping during the turn maneuver. This paper proposes a fusion and analysis of heterogeneous data, mainly involved in driving, to determine the risk factor of particular maneuvers within the drive. It also explains the segmentation and risk analysis of the turn maneuver in a drive.

Biological performance of a polycaprolactone-based scaffold used as fusion cage device in a large animal model of spinal reconstructive surgery

A bioactive and bioresorbable scaffold fabricated from medical grade poly (epsilon-caprolactone) and incorporating 20% beta-tricalcium phosphate (mPCL–TCP) was recently developed for bone regeneration at load bearing sites. In the present study, we aimed to evaluate bone ingrowth into mPCL–TCP in a large animal model of lumbar interbody fusion. Six pigs underwent a 2-level (L3/4; L5/6) anterior lumbar interbody fusion (ALIF) implanted with mPCL–TCP þ 0.6 mg rhBMP-2 as treatment group while four other pigs implanted with autogenous bone graft served as control. Computed tomographic scanning and histology revealed complete defect bridging in all (100%) specimen from the treatment group as early as 3 months. Histological evidence of continuing bone remodeling and maturation was observed at 6 months. In the control group, only partial bridging was observed at 3 months and only 50% of segments in this group showed complete defect bridging at 6 months. Furthermore, 25% of segments in the control group showed evidence of graft fracture, resorption and pseudoarthrosis. In contrast, no evidence of graft fractures, pseudoarthrosis or foreign body reaction was observed in the treatment group. These results reveal that mPCL–TCP scaffolds could act as bone graft substitutes by providing a suitable environment for bone regeneration in a dynamic load bearing setting such as in a porcine model of interbody spine fusion.