Motor function recovery: deciphering a regenerative niche at the neuromuscular synapse

The coordinated movement of many organisms relies on efficient nerve–muscle communication at the neuromuscular junction (NMJ), a peripheral synapse composed of a presynaptic motor axon terminal, a postsynaptic muscle specialization, and non-myelinating terminal Schwann cells. NMJ dysfunctions are caused by traumatic spinal cord or peripheral nerve injuries as well as by severe motor pathologies. Compared to the central nervous system, the peripheral nervous system displays remarkable regenerating abilities; however, this capacity is limited by the denervation time frame and depends on the establishment of permissive regenerative niches. At the injury site, detailed information is available regarding the cells, molecules, and mechanisms involved in nerve regeneration and repair. However, a regenerative niche at the final functional step of peripheral motor innervation, i.e. at the mature neuromuscular synapse, has not been deciphered. In this review, we integrate classic and recent evidence describing the cells and molecules that could orchestrate a dynamic ecosystem to accomplish successful NMJ regeneration. We propose that such a regenerative niche must ensure at least two fundamental steps for successful NMJ regeneration: the proper arrival of incoming regenerating axons to denervated postsynaptic muscle domains, and the resilience of those postsynaptic domains, in morphological and functional terms. We here describe and combine the main cellular and molecular responses involved in each of these steps as potential targets to help successful NMJ regeneration.     

Nocardia brasiliensis: in vitro and in vivo growth response to steroid sex hormones

As actinomycetoma is more frequent in males than in females, the possibility that hormones might modify theNocardia brasiliensis growth and the course of experimental actinomycetoma was explored. FiveN. brasiliensis strains were grown on Sabouraud agar containing estradiol, progesterone or testosterone, in 3 different concentrations. Colony diameters were measured weekly for 7 weeks.N. brasiliensis strains were also grown in Sabouraud broth containing hormones. Glucose concentration was measured weekly for 6 weeks. Finally, experimental actinomycetoma was produced in male and female hormone-treated mice. Invasion rate, plantar pad diameter and positive retrocultures were assessed. In vitro experiments showed that progesterone and testosterone inhibitN. brasiliensis growth, manifested by lower colony diameters and greater glucose concentrations. In vivo experiments demonstrated that estradiol limits actinomycetoma development. Progesterone and testosterone induced greater diameters of inoculated plantar pads and greater invasion rates with greater positive culture numbers than estradiol. Results partially explain the resistance of females to actinomycetoma.     

Enhanced production of triacylglycerols and polyunsaturated fatty acids in novel acid-tolerant mutants of the green microalga Chlorella saccharophila

Bioprocess and Biosystems Engineering - In this study, the microalga Chlorella saccharophila was subjected to ultraviolet (UV) mutagenesis, and mutant screening was conducted based on acidity...     

Polycyclic Aromatic Hydrocarbon Profiles of Some Brands of Canned Fish in the Nigerian Market

Concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) were determined in selected popular brands of canned fish (mackerel, sardine, and tuna) consumed in Nigeria with a view to providing information on the health risk associated with consumption of these products. The concentrations of PAHs were measured by gas chromatography equipped with flame ionization detection (GC-FID) after dichloromethane/hexane extraction and clean-up. The concentrations of Σ16 PAHs in these brands of canned fish varied from 174.6 to 350.8 μg/kg, 187.4 to 592.5 μg/kg, and 204 to 264.6 μg/kg for mackerel, sardine, and tuna, respectively. Benzo(a)pyrene was detected in 48% of the investigated brands at concentrations higher than the maximum tolerable limit of 5 μg/kg. The daily intake of PAHs from the consumption of any brand of these canned fish ranged from not detected (nd) to 54.3 ng BaP/kg bw/day, nd to 56.4 ng PAH2/kg bw/day, nd to 86.4 ng PAH4/kg bw/day, and nd to 153.7 ng PAH8/kg bw/day. The estimated margin of exposure (MOE) values (BaP-MOE, PAH2-MOE, PAH4-MOE, and PAH8-MOE) in a significant proportion of the brands was less than 10,000, which indicates a potential health risk for the consumers of these brands of canned fish.     

Large-scale population genetics of the mountain ant Proformica longiseta (Hymenoptera: Formicidae)

Proformica longiseta Collingwood is an endemic ant found in southeastern Spain that inhabits high mountains and is widespread within an altitude range. We have studied the population genetics and biogeography of 14 populations of P. longiseta throughout its distribution using microsatellites and mitochondrial data. Populations are strongly structured for both markers and show isolation by distance, which together with the absence of intra-population variation in mitochondrial DNA suggest strong female philopatry and limited male dispersal. In spite of this, no recent bottlenecks or inbreeding were detected. Finally, we report on a population currently located where it did not exist 14 years ago, above the usual altitudinal limit known for the species, which may be due to recent colonization enhanced by global warming.     

Near-infrared and two-dimensional fluorescence spectroscopy monitoring of monoclonal antibody fermentation media quality: Aged media decreases cell growth

In biomanufacturing processes, the influence of feedstock components on product yield and quality is considerable and often poorly understood. Here we describe the capabilities of near-infrared spectroscopy (NIRS) and two dimensional (2D)-fluorescence spectroscopy in detecting chemical changes over time in two types of culture media (one basal media and one feed media) used in the production of monoclonal antibodies (mAbs) by Chinese hamster ovary (CHO) cells. Both spectroscopies were able to detect compositional changes in basal media over storage period of 12 weeks. NIRS was more effective in detecting changes in feed medium composition. The impact of storage time in process performance was evaluated by using aged media components in mAb cultivations. The study suggests that basal media aging results in a decrease of the integral of viable cells (IVC) (cell growth over time), while product titer is not significantly affected. Feed media appears to be less sensitive to storage and no correlation between the age of the media and cell culture performance was detected. Results obtained provide a basis on which to further improve cell culture raw material quality assessment using vibrational (e.g. NIRS) and optical (e.g. 2D-fluorescence) spectroscopic methods.     

Genotyping and haplotyping of polymorphisms directly from genomic DNA via coupled amplification and sequencing (CAS).

Coupled amplification and sequencing (CAS) allows a segment of DNA to be sequenced directly from genomic DNA. An initial PCR amplification stage selects and amplifies the target. During a subsequent stage both strands of the target segment are sequenced simultaneously and amplified further. We show that CAS can readily identify variant base pairs. Genotyping of a population for known sequence variation can be achieved simply and directly from genomic DNA of each organism by performing CAS only for the variant bases. The procedure supercedes development and optimization of alternative typing assays based on oligonucleotide hybridization or ligation. In addition, we show that competitive oligonucleotide priming with allelic primers can be readily performed in concert with the second stage of CAS. The combination of techniques allows sequencing of a single chromosome from a heterozygous genomic sample and direct haplotyping of the polymorphism at the priming site with any others encompassed within the amplified segment.     

Isotopic marking of natural enemies fed on C4 honey for habitat management studies in agroecosystems

1. To improve biological control and habitat management, how pest predators spread from natural habitats to crops must be understood. We studied whether intrinsic differences in stable-isotopic ratios of C and N from an artificial C₄ (sugar-cane) or C₃ (muti-flower honey) diet could help mark and track predators that feed on them.
2. Two aphid predators solely feeding on sugar resources as adults were used: the green lacewing Chrysoperla carnea s.l., and the parasitic wasp Aphidius colemani. δ¹³C and δ1⁵N values from wild individuals helped distinguish them from marked ones and determine the habitat resources they used.
3. Green lacewings fed on C₄ showed significantly higher δ¹³C values than those on C3 and wild individuals. However, parasitoid values were unaffected, with no mark acquired. Logistic regression was fitted to assess the probability of green lacewings having either diet with a probability of 0.93. Marks were acquired after 5 days and were detectable 20 days after switching diets with a probability of 0.67. Similar δ¹⁵N values for both wild populations indicated both predators had similar prey, but different vegetal resources (different δ¹³C values).
4. Sugar-cane honey is a natural and reliable marker for tracking lacewing populations in the field, but not for parasitoids.

     

Alpha-fetoprotein in tumours derived from cystic and simple embryoid bodies.

Cellular aggregates called embryoid bodies (EB) have been obtained from the experimental teratocarcinoma (TC) 0TT6050. Two morphological types of EB can be differentiated, which are injected subcutaneously into isogenic 129/Sv mice. The tumors are collected 20 and 30 days after EB injection and processed histologically, and immunohistochemically with anti-alpha-fetoprotein (alpha-FP) antibodies. Our results indicate that the histological pattern of the tumors is related to the degree of morphological organization of the EB used.