The Autographa californica Multiple Nucleopolyhedrovirus ORF78 Is Essential for Budded Virus Production and General Occlusion Body Formation

ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in the baculovirus life cycle, an AcMNPV mutant with ac78 deleted, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype, indicating that no infectious budded viruses (BVs) were produced. The defect in BV production was also confirmed by both viral titration and Western blotting. However, viral DNA replication was unaffected, and occlusion bodies were formed. An analysis of BVs and occlusion-derived viruses (ODVs) revealed that AC78 is associated with both forms of the virions and is an envelope structural protein. Electron microscopy revealed that AC78 also plays an important role in the embedding of ODV into the occlusion body. The results of this study demonstrate that AC78 is a late virion-associated protein and is essential for the viral life cycle.     

Gene expression defines natural changes in mammalian lifespan

Mammals differ more than 100‐fold in maximum lifespan, which can be altered in either direction during evolution, but the molecular basis for natural changes in longevity is not understood. Divergent evolution of mammals also led to extensive changes in gene expression within and between lineages. To understand the relationship between lifespan and variation in gene expression, we carried out RNA‐seq‐based gene expression analyses of liver, kidney, and brain of 33 diverse species of mammals. Our analysis uncovered parallel evolution of gene expression and lifespan, as well as the associated life‐history traits, and identified the processes and pathways involved. These findings provide direct insights into how nature reversibly adjusts lifespan and other traits during adaptive radiation of lineages.     

Dynamic network rewiring determines temporal regulatory functions in Drosophila melanogaster development processes

The identification of network motifs has been widely considered as a significant step towards uncovering the design principles of biomolecular regulatory networks. To date, time‐invariant networks have been considered. However, such approaches cannot be used to reveal time‐specific biological traits due to the dynamic nature of biological systems, and hence may not be applicable to development, where temporal regulation of gene expression is an indispensable characteristic. We propose a concept of a “temporal sequence of network motifs”, a sequence of network motifs in active sub‐networks constructed over time, and investigate significant network motifs in the active temporal sub‐networks of Drosophila melanogaster . Based on this concept, we find a temporal sequence of network motifs which changes according to developmental stages and thereby cannot be identified from the whole static network. Moreover, we show that the temporal sequence of network motifs corresponding to each developmental stage can be used to describe pivotal developmental events.     

Target-derived molecules that influence the development of neurons in the avian ciliary ganglion

The developing avian ciliary ganglion has been a particularly amenable system for the identification, isolation, and characterization of putative target-derived molecules that mediate retrograde interaction. To date a number of biochemically distinct activities that regulate neuronal survival, transmitter phenotype, and chemosensitivity of ciliary ganglion neruons have been identified. Of these, only two survival-promoting molecules have been purified to homogeneity: ciliary neurotrophic factor and a related molecule, growth-promoting activity. A somatostatin-inducing activity found in cultured choroid cells is very likely to be chick activin A. Other molecules that regulate acetylcholine and acetylcholine receptor expression comigrate on a gel filtration column at a molecular weight of 50–60 kD, but they have yet to be isolated. Once molecules that mimic retrorgrade influences are identified, a number of criteria must be met before their physiological significance can be established. These criteria are (1) availability of the molecule from the target at the appropriate time in development: (2) ability of the neurons to respond to the molecule at the appropriate time in development: (3) demonstration that blocking the activity or availability of the molecule is able to block the target-derived developmental change expressed in the neurons. Of the molecules that are thought to retrogradely influence ciliary neuron development, only growth-promoting activity is known to meet criteria 1 and 2, and experiments of growth-promoting activity in vivo will exacerbate normal cell death. 1994 John Wiley & Sons, Inc.     

Cell-to-cell fusion of lens fiber cells in situ: correlative light, scanning electron microscopic, and freeze-fracture studies

We have discovered cell-to-cell fusion between fiber cells of adult frog lenses in situ. Stereo scanning electron microscopy (SEM) revealed fusion between neighboring fiber cells in radial cell columns (RCCs) and in the same growth ring, respectively. Cell-to-cell fusion of fiber cells in the lens produced fusion zones that in cross-section were larger and of different polygonal shapes than unfused fiber cells. The shape and sizes of fiber cells surrounding fusion zones and the alignment of RCCs were also altered. Serial sectioning through fusion zones confirmed that they were areas of cell-to-cell continuity established by the union of neighboring fiber cells as seen by SEM. Fusion zones represent a previously unrecognized intercellular pathway in the adult frog lens. Although numerous fusion zones were seen throughout the lens cortex and nucleus, cell-to-cell fusion was rarely observed to have occurred between elongating fiber cells. Interestingly, communicating junctions with an unusual ultrastructure that closely resembles the appearance of membranes in the process of fusion demonstrated in other systems were frequently seen in the region of the superficial cortex where fusion zones were most numerous. The fact that such unusual communicating junctions were not found in any other region of the lens leads us to speculate that structural changes in fiber cell communicating junctions may herald the formation of fusion zones and that the initial site of cell-to-cell fusion between fiber cells may be within communicating junctional plaques.     

Water quality assessment of the Siluko River,southern Nigeria

The water quality of the Siluko River, Edo State, Nigeria was investigated from March to August 2015 to determine its suitability for drinking and usage for domestic purposes. Water samples collected from three stations were tested for thirteen physico-chemical parameters using standard analytical procedures. Temperature, phosphate and chloride were significantly different across the three stations. All other parameters, with the exception of turbidity, dissolved oxygen and phosphate, were within the permissible limits recommended by the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO). Water Quality Index (WQI) values ranged from 11.24 to 16.15, indicating excellent water quality. While the quality of the water from the Siluko River is suitable for drinking and domestic usage, to prevent future deterioration of the water, it is recommended that the regulating authorities monitor effluents discharged into the river from human activities.