Metabolic flux analysis for optimizing the specific growth rate of recombinant <Emphasis Type="Italic">Aspergillus niger</Emphasis>

A comprehensive metabolic network comprising three intracellular compartments (cytoplasm, mitochondrion and peroxisome) was developed for Aspergillus niger. The metabolic flux network includes carbohydrate and amino acid metabolism in both anabolic and catabolic reactions. Linear programming was used for the optimization of the specific growth rates in combination with 37 measured input and output fluxes of the key metabolites to evaluate corresponding intracellular flux distributions throughout the batch fermentations. Logarithmic sensitivity analysis revealed that the addition of proline, alanine and glutamate benefited growth in defined media. The experimental observations and flux analysis showed that tyrosine was a potential candidate for biomass production improvement. Model predictions was verified by conducting batch and fed-batch fermentations and it was found that the addition of the four amino acids according to the predetermined schedule resulted in a 44 and 41% improvements in biomass and recombinant protein productions, respectively.     

不同浓度下的中药复方对四川白兔生长的影响

本次研究旨在探讨中药复方对四川白兔生长性能、免疫功能及其抗氧化情况的作用。采用单因子实验设计,选择30日龄断奶四川白兔仔兔100只,随机分为5组(每组20只,雌雄各半),试验3组为高浓度组(基础日粮+3%中药添加剂),试验2组为中等浓度组(基础日粮+2%中药添加剂),试验1组为低浓度组(基础日粮+1%中药添加剂),试验4组为阳性组(基础日粮+1%杆菌肽锌+1%硫酸黏杆菌素),对照组饲喂基础日粮。试验期为56 d,其中预试期为7 d,正试期为49 d。正试期内测定试兔的生长性能,试验结束时测定试兔的抗氧化和免疫指标。结果显示:高浓度组显著提高了兔的Ig M (p<0.05),中等浓度组极显著提高了兔的Ig A (p<0.01),且死亡率均为0;低浓度组和高浓度组显著提高了兔丙二醛(MDA)或超氧化物歧化酶(SOD)的活性;低浓度组显著提高了兔的脾指数(p<0.05);高浓度组显著提高或降低了兔十二指肠的绒毛高度或隐窝深度(p<0.05);中等浓度组显著提高了回肠的绒毛高度(p<0.0.5)。饲粮添加一定的中药复方不仅能改善兔子的生长性能,增强四川白兔的免疫能力及抗氧化性,也可以降低四川白兔死亡发生概率。     

Sex,but not skin tone affects penetration of red‐light (660 nm) through sites susceptible to sports injury in lean live and cadaveric tissues

Red‐light treatment is emerging as a novel therapy for promoting tissue recovery but data on red‐light penetration through human tissues are lacking. We aimed to: (1) determine the effect of light irradiance, tissue thickness, skin tone, sex and bone/muscle content on 660 nm light penetration through common sites of sports injuries, and (2) establish if cadaver tissues serve as a useful model for predicting red‐light penetration in live tissues. Live and cadaver human tissues were exposed to 660 nm light at locations across the skull, spinal cord and upper and lower limbs. Red‐light was produced by a light emitting diode array of various irradiances (15‐500 mW/cm²) and measured by a light‐probe positioned on the tissue surface opposite to the light emitting diodes. 100 mW/cm² successfully penetrated tissue <50 mm thick; a disproportionate irradiance increase was required to achieve deeper penetration. Penetration was unaffected by skin tone, increased with irradiance and relative bone/muscle composition, and decreased with greater tissue thickness and in males. Live and cadaveric tissue penetration did not differ statistically for tissues <50 mm but cadavers required more red‐light to penetrate >50 mm. These results assist clinicians and researchers in determining red‐light treatment intensities for penetrating human tissues.      

Hyperspectral optical coherence tomography for in vivo visualization of melanin in the retinal pigment epithelium

Previous studies for melanin visualization in the retinal pigment epithelium (RPE) have exploited either its absorption properties (using photoacoustic tomography or photothermal optical coherence tomography [OCT]) or its depolarization properties (using polarization sensitive OCT). However, these methods are only suitable when the melanin concentration is sufficiently high. In this work, we present the concept of hyperspectral OCT for melanin visualization in the RPE when the concentration is low. Based on white light OCT, a hyperspectral stack of 27 wavelengths (440‐700 nm) was created in post‐processing for each depth‐resolved image. Owing to the size and shape of the melanin granules in the RPE, the variations in backscattering coefficient as a function of wavelength could be identified—a result which is to be expected from Mie theory. This effect was successfully identified both in eumelanin‐containing phantoms and in vivo in the low‐concentration Brown Norway rat RPE.      

Skin and subcutaneous fat morphology alterations under the LED or laser treatment in rats in vivo

The main objective of this work is to quantify the impact of photodynamic/photothermal treatment by using visible LED and NIR laser irradiation through the skin of subcutaneous fat in vivo followed up by tissue sampling and histology. The optical method may provide reduction of regional or site‐specific accumulations of abdominal or subcutaneous adipose tissue precisely and least‐invasively by inducing cell apoptosis and controlled necrosis of fat tissue. As photodynamic/photothermal adipose tissue sensitizers Brilliant Green (BG) or Indocyanine Green (ICG) dyes were injected subcutaneously in rats. The CW LED device (625 nm) or CW diode laser (808 nm) were used as light sources, respectively. Biopsies of skin together with subcutaneous tissues were taken for histology. The combined action BG‐staining and LED‐irradiation (BG + LED) or ICG‐staining and NIR‐laser irradiation (ICG + NIR) causes pronounced signs of damage of adipose tissue characterized by a strong stretching, thinning, folding and undulating of cell membranes and appearance of necrotic areas. As a posttreatment after 14 days only connective tissue was observed at the site of necrotic areas. The data obtained are important for safe light treatment of site‐specific fat accumulations, including cellulite. This work provides a basis for the development of fat lipolysis technologies and to move them to clinical applications. Schematics of animal experiment.      

Molecular pathways linking non‐shivering thermogenesis and obesity: focusing on brown adipose tissue development

An increase in energy intake and/or a decrease in energy expenditure lead to fat storage, causing overweight and obesity phenotypes. The objective of this review was to analyse, for the first time using a systematic approach, all published evidence from the past 8 years regarding the molecular pathways linking non‐shivering thermogenesis and obesity in mammals, focusing on mechanisms involved in brown adipose tissue development. Two major databases were scanned from 2006 to 2013 using ‘brown adipose tissue’ AND ‘uncoupling protein‐1’ AND ‘mammalian thermoregulation’ AND ‘obesity’ as key words. A total of 61 articles were retrieved using the search criteria. The available research used knockout methodologies, various substances, molecules and agonist treatments, or different temperature and diet conditions, to assess the molecular pathways linking non‐shivering thermogenesis and obesity. By integrating the results of the evaluated animal and human studies, our analysis identified specific molecules that enhance non‐shivering thermogenesis and metabolism by: (i) stimulating ‘brite’ (brown‐like) cell development in white adipose tissue; (ii) increasing uncoupling protein‐1 expression in brite adipocytes; and (iii) augmenting brown and/or brite adipose tissue mass. The latter can be also increased through low temperature, hibernation and/or molecules involved in brown adipocyte differentiation. Cold stimuli and/or certain molecules activate uncoupling protein‐1 in the existing brown adipocytes, thus increasing total energy expenditure by a magnitude proportional to the number of available brown adipocytes. Future research should address the interplay between body mass, brown adipose tissue mass, as well as the main molecules involved in brite cell development.     

Entraining effects of variations in light spectral composition on the rest-activity rhythm of a nocturnal rodent

The ability to predict and adjust physiology and behavior to recurring environmental events has been necessary for survival on Earth. Recent discoveries revealed that not only changes in irradiance but also light spectral composition can stimulate the suprachiasmatic nucleus (SCN), ensuring the body’s synchronization to the environment. Therefore, using a lighting system that modulates spectral composition during the day using combined red-green-blue (RGB) lights, we evaluated the effect of variations in light spectral composition on the rest-activity rhythm of rodents. Male Wistar rats (n = 17) were gestated and raised under different lighting conditions and exposed to a long photoperiod (16 h light: 8 h dark). The difference between groups was the presence of variations in light spectral composition during the day (RGB-v) to simulate daily changes in natural light, or not (RGB-f). After weaning, spontaneous motor activity was recorded continuously for rhythm evaluation. Our results indicated that animals under RGB-v did not present a reactive peak of activity after the beginning of the light phase, suggesting that this group successfully detected the variations aimed at mimicking daily alterations of natural light. Furthermore, RGB-v animals exhibited an earlier activity acrophase in comparison to animals under RGB-f (RGB-v = 12:16 – “hh:mm”, RGB-f = 13:02; p < 0.001), which might have been due to the capability to predict the beginning of the dark phase when exposed to variations in light spectrum. However, this earlier activity acrophase can be also explained by the blue-light peak that occurred in RGB-v. The spectral and waveform analysis of daily patterns of motor activity revealed that rats in the RGB-v group were better entrained to a circadian rhythm throughout the experiment. RGB-v showed higher interdaily stability (IS) values (29.75 ± 6.5, n = 9) than did RGB-f (t₍₁₅₎ = 2.74, p = 0.015). Besides, the highest power content (PC) on the first harmonic (circadian) was reached earlier in the RGB-v group. The circadianity index (CI) of the whole period was higher in the RGB-v group (t₍₁₅₎ = 3.47, p = 0.003). Thus, we could consider that locomotor activity rhythm was entrained to the light-dark cycle in the RGB-v rats earlier compared to the RGB-f rats. Our results provide additional evidence for the effect of variations in light spectral composition on the rest-activity pattern of nocturnal rodents. This suggests that these animals might predict the arrival of the activity phase by its advanced acrophase when exposed to RGB-v, demonstrating a better synchronization to a 24-h rhythm.     

The loss of ecosystem-services emerging from artificial light at night

Light pollution is increasing worldwide, affecting human health and ecosystem quality. The adverse effect of this novel pollution, mediated in mammals by suppression of the pineal neuro-hormone melatonin production and secretion, particularly by short wavelength (SWL) illumination. Currently, this problem is not challenged sufficiently, even ignored by decision-makers at local and national levels, as well as other related organizations. Therefore, we assume that the correct way to deal with it will be by treating the dark night as an ecosystem-service for temporal organization of humans as other organisms. Therefore, chasing darkness away and mainly by SWL illumination is as giving up the natural light/dark cycles offered as an ecosystem-service. So far, we have no environmental economic tools for assessing the real coast of the health damages or reduction in pollination caused by light pollution. Using Artificial Light at Night (ALAN) as a loss of ecosystem-services will enable us to give it a realistic economic value thus an opportunity to re-evaluate the environmental cost of SWL efficient illumination. This will also help decision-makers to move to the next stage of illumination preferring sustainable illumination.