43 research outputs found
Inbreeding in Rainbow Trout (Salmo gairdneri): Analysis of Lethal Temperature Tolerence
Inbreeding in rainbow trout (Salmo gairdneri) was evaluated in relation to an altered environment (upper lethal temperature 29 C), at four levels of inbreeding. At each level of inbreeding mean time to death for inbred, female-outbred half-sib, male-outbred half-sib and outbred families were evaluated. In all cases inbreds were less resistant to lethal temperature than were respective outbred families. Analysis of variance 9Snedecorâs F) and multiple range analysis (Tukeyâs âwâ procedure) provided inference limitations. Inbred fish were 82% less resistant to lethal temperature as comared to the respective outbred family at 50% inbreeding and 19% less resistant at 25% inbreeding. How inbreeding practices influence stocks of rainbow trout are summarized below: A. Domestic stocks of rainbow trout are inbred to an unknown and varying degree. B. Inbreeding has been common in domestic fish stock for over 100 years in the United States. C. Stocking domestic fish in natural waters has destroyed most genetically unique populations probably by genetic âdilutionâ. D. Millions of hatchery fish have been broadcasted internationally with unknown consequences in regard to the genetic structure of the original wild populations. E. Inbred groups can show increased phenotypic variation when compared to their outbred countergroups for some traits. F. Highly inbred fish may suffer reduced genetic variability lowering tolerance to environmental rates
The Pictet-Spengler reaction updates its habits
The Pictet-Spengler reaction (P-S) is one of the most direct, efficient, and variable synthetic method for the construction of privileged pharmacophores such as tetrahydroisoquinolines (THIQs), tetrahydro-β-carbolines (THBCs), and polyheterocyclic frameworks. In the lustro (five-year period) following its centenary birthday, the P-S reaction did not exit the stage but it came up again on limelight with new features. This review focuses on the interesting results achieved in this period (2011â2015), analyzing the versatility of this reaction. Classic P-S was reported in the total synthesis of complex alkaloids, in combination with chiral catalysts as well as for the generation of libraries of compounds in medicinal chemistry. The P-S has been used also in tandem reactions, with the sequences including ring closing metathesis, isomerization, Michael addition, and Gold- or Brønsted acid-catalyzed N-acyliminium cyclization. Moreover, the combination of P-S reaction with Ugi multicomponent reaction has been exploited for the construction of highly complex polycyclic architectures in few steps and high yields. The P-S reaction has also been successfully employed in solid-phase synthesis, affording products with different structures, including peptidomimetics, synthetic heterocycles, and natural compounds. Finally, the enzymatic version of P-S has been reported for biosynthesis, biotransformations, and bioconjugations
Naturally-occurring alkaloids of plant origin as potential antimicrobials against antibiotic-resistant infections
Antibiotic resistance is now considered a worldwide problem that puts public health at risk. The onset of bacterial strains resistant to conventional antibiotics and the scarcity of new drugs have prompted scientific research to re-evaluate natural products as molecules with high biological and chemical potential. A class of natural compounds of significant importance is represented by alkaloids derived from higher plants. In this review, we have collected data obtained from various research groups on the antimicrobial activities of these alkaloids against conventional antibiotic-resistant strains. In addition, the structure-function relationship was described and commented on, highlighting the high potential of alkaloids as antimicrobials
Gene Expression Analysis of Forskolin Treated Basilar Papillae Identifies MicroRNA181a as a Mediator of Proliferation
Auditory hair cells spontaneously regenerate following injury in birds but not mammals. A better understanding of the molecular events underlying hair cell regeneration in birds may allow for identification and eventually manipulation of relevant pathways in mammals to stimulate regeneration and restore hearing in deaf patients.Gene expression was profiled in forskolin treated (i.e., proliferating) and quiescent control auditory epithelia of post-hatch chicks using an Affymetrix whole-genome chicken array after 24 (n = 6), 48 (n = 6), and 72 (n = 12) hours in culture. In the forskolin-treated epithelia there was significant (p<0.05; >two-fold change) upregulation of many genes thought to be relevant to cell cycle control and inner ear development. Gene set enrichment analysis was performed on the data and identified myriad microRNAs that are likely to be upregulated in the regenerating tissue, including microRNA181a (miR181a), which is known to mediate proliferation in other systems. Functional experiments showed that miR181a overexpression is sufficient to stimulate proliferation within the basilar papilla, as assayed by BrdU incorporation. Further, some of the newly produced cells express the early hair cell marker myosin VI, suggesting that miR181a transfection can result in the production of new hair cells.These studies have identified a single microRNA, miR181a, that can cause proliferation in the chicken auditory epithelium with production of new hair cells
Pathogenesis, diagnosis and management of pneumorrhachis
Pneumorrhachis (PR), the presence of intraspinal air, is an exceptional but eminent radiographic finding, accompanied by different aetiologies and possible pathways of air entry into the spinal canal. By reviewing the literature and analysing a personal case of traumatic cervical PR after head injury, we present current data regarding the pathoanatomy, clinical and radiological presentation, diagnosis and differential diagnosis and treatment modalities of patients with PR and associated pathologies to highlight this uncommon phenomenon and outline aetiology-based guidelines for the practical management of PR. Air within the spinal canal can be divided into primary and secondary PR, descriptively classified into extra- or intradural PR and aetiologically subsumed into iatrogenic, traumatic and nontraumatic PR. Intraspinal air is usually found isolated not only in the cervical, thoracic and, less frequently, the lumbosacral regions but can also be located in the entire spinal canal. PR is almost exceptional associated with further air distributions in the body. The pathogenesis and aetiologies of PR are multifold and can be a diagnostic challenge. The diagnostic procedure should include spinal CT, the imaging tool of choice. PR has to be differentiated from free intraspinal gas collections and the coexistence of air and gas within the spinal canal has to be considered differential diagnostically. PR usually represents an asymptomatic epiphenomenon but can also be symptomatic by itself as well as by its underlying pathology. The latter, although often severe, might be concealed and has to be examined carefully to enable adequate patient treatment. The management of PR has to be individualized and frequently requires a multidisciplinary regime
Amyloid PET as a marker of normal-appearing white matter early damage in multiple sclerosis: correlation with CSF β-amyloid levels and brain volumes
PURPOSE
The disease course of multiple sclerosis (MS) is unpredictable, and reliable prognostic biomarkers are needed. Positron emission tomography (PET) with β-amyloid tracers is a promising tool for evaluating white matter (WM) damage and repair. Our aim was to investigate amyloid uptake in damaged (DWM) and normal-appearing WM (NAWM) of MS patients, and to evaluate possible correlations between cerebrospinal fluid (CSF) β-amyloid (Aβ) levels, amyloid tracer uptake, and brain volumes.
METHODS
Twelve MS patients were recruited and divided according to their disease activity into active and non-active groups. All participants underwent neurological examination, neuropsychological testing, lumbar puncture, brain magnetic resonance (MRI) imaging, and F-florbetapir PET. Aβ levels were determined in CSF samples from all patients. MRI and PET images were co-registered, and mean standardized uptake values (SUV) were calculated for each patient in the NAWM and in the DWM. To calculate brain volumes, brain segmentation was performed using statistical parametric mapping software. Nonparametric statistical analyses for between-group comparisons and regression analyses were conducted.
RESULTS
We found a lower SUV in DWM compared to NAWM (p <â0.001) in all patients. Decreased NAWM-SUV was observed in the active compared to non-active group (p <â0.05). Considering only active patients, NAWM volume correlated with NAWM-SUV (pâ=â0.01). Interestingly, CSF Aβ concentration was a predictor of both NAWM-SUV (râ=â0.79; pâ=â0.01) and NAWM volume (râ=â0.81, pâ=â0.01).
CONCLUSIONS
The correlation between CSF Aβ levels and NAWM-SUV suggests that the predictive role of β-amyloid may be linked to early myelin damage and may reflect disease activity and clinical progression