Mitochondrial changes associated with demyelination: consequences for axonal integrity

The loss of myelin sheath (demyelination) renders axons vulnerable to a variety of insults. Axonal degeneration is well recognised in inflammatory demyelinating disorders of the central nervous system (CNS) such as multiple sclerosis (MS) and also certain neurodegenerative diseases. Energy required for nerve impulse conduction and maintenance of structural integrity of axons is met by mitochondria. Based on the distribution of ion channels and the Na(+)/K(+) ATPase, the energy requirements of demyelinated and dysmyelinated axons are likely to differ from myelinated axons. In this review we discuss the changes in mitochondrial presence within axons in relation to presence or absence of healthy myelin sheaths and propose the increase in mitochondrial presence following demyelination as an adaptive process. An energy deficit within demyelinated axons is likely to be more detrimental compared to myelinated axons, judging by the neuropathological findings in primary mitochondrial disorders due to mitochondrial and nuclear DNA mutations and the mitochondrial changes that follow demyelination. Agents that enhance and protect mitochondria, as potential therapy, need to be considered and investigated in earnest for demyelinating disorders of the CNS such as MS.     

Learning to feed in the dark: how light level influences feeding in the hawkmoth Manduca sexta

Nocturnal insects like moths are essential for pollination, providing resilience to the diurnal pollination networks. Moths use both vision and mechanosensation to locate the nectary opening in the flowers with their proboscis. However, increased light levels due to artificial light at night (ALAN) pose a serious threat to nocturnal insects. Here, we examined how light levels influence the efficacy by which the crepuscular hawkmoth Manduca sexta locates the nectary. We used three-dimensional-printed artificial flowers fitted with motion sensors in the nectary and machine vision to track the motion of hovering moths under two light levels: 0.1 lux (moonlight) and 50 lux (dawn/dusk). We found that moths in higher light conditions took significantly longer to find the nectary, even with repeated visits to the same flower. In addition to taking longer, moths in higher light conditions hovered further from the flower during feeding. Increased light levels adversely affect learning and motor control in these animals.     

Assessment of land degradation through people's perception and knowledge toward management in Oman

The focus of this study was to determine people's perception and knowledge toward land degradation and management in the Al-Suwaiq Wilayat of Al-Batinah North, Sultanate of Oman. This area has been under pressure and competed for by several uses. Structured questionnaire survey with questions related to land degradation and management were used for the assessment in the beginning of the year 2016. In total, 238 households were surveyed in the Wilayat following a random sampling method. The results indicate that residents were aware of the on-going land degradation due to salinization, construction, and public work activities in the area. Residents perceive land degradation mainly by reduced yields and the most important perceived indicator is loss of soil nutrients that reduced crop yield, reduction in family income followed by increased cost for management. The study findings highlight that sustainable use and management of land resources is required in creating awareness programs to educate residents and successful policies toward improving land degradation in the area. In addition, this study shows that appropriate enabling policies and institutional arrangements are also required. Such measures should combine proven indigenous practices as well as knowledge into technical approaches toward ensuring local participation in decision-making.