Systematics of green algae resembling <i>Ulva conglobata</i>, with a description of <i>Ulva adhaerens</i> sp. nov. (Ulvales, Ulvophyceae)

<div><p>A phylogenetic and morphological study of green algae resembling <i>Ulva conglobata</i> from Japan was undertaken, along with morphological observations of the original material of <i>U. conglobata</i> Kjellman. The samples resembling <i>U. conglobata</i> included five genetically distinct species: <i>U. fasciata, U. pertusa, U. tanneri, Ulva</i> sp. 1 and <i>Ulva</i> sp. 2. The discovery of marginal denticulations in some of the original material of <i>U. conglobata</i>, made it possible to distinguish those species without denticulations: <i>U. pertusa, U. tanneri</i> and <i>Ulva</i> sp. 2. The morphological characteristics of <i>Ulva</i> sp. 1 matched those of <i>U. conglobata</i>, but <i>Ulva</i> sp. 1 was not clearly identified as <i>U. conglobata</i> owing to the lack of DNA sequence data of the original material. <i>Ulva</i> sp. 2 had lobes adhering to each other by rhizoids. This morphological feature is stable in <i>Ulva</i> sp. 2 and unique among <i>Ulva</i> species. In conjunction with the molecular data, <i>Ulva</i> sp. 2 was described as a new species, <i>U. adhaerens</i> sp. nov. This species features rhizoidal extensions in regions other than the base and an elaborate arrangement of the extensions used for adhesion. It thereby expands our knowledge of the morphogenesis of the morphologically simple genus <i>Ulva</i>.</p></div

<i>In vivo</i> MRI sample images.

<p>(A) Sample T2-weighted images for structural volumetry assessments. Images are from scans taken at 4, 8, 12 and 14 weeks of age at anatomically matching slices. (B) Hot/cold scaled maps of T2 relaxation times for the study of T2 relaxivity, these are represented on anatomically identical images to those in (A). Bg = bregma.</p

Experimental design and body weight of WT and R6/2 mice.

<p>(A) Experimental protocol. Mice were scanned for MRI measures at 4, 8, 12 and 14 weeks of age. The final MR scan was terminal, mice were culled and brains removed for histological analysis. Performance on a rotarod (RR) and behaviors expressed within an open field (OF) were assessed at 5, 9 and 13 weeks of age. Cognitive performance at the passive avoidance (PA) test was measured at 6 weeks of age only. (B & C) Assessment of body weight. Both male (B) and female (C) R6/2 mice exhibited progressive loss in body weight. This was highly significant from 6 weeks of age for males, but only reached statistical significance at 14 weeks of age for the females. Data presented as means ± SEM; ***p<.001.</p

Behavioral characterization of WT and R6/2 mice.

<p>(A & B) R6/2s exhibited a decline in latency to fall from the rotarod beam with age, reaching statistical significance from 9 weeks of age for the female mice, but only at 13 weeks of age for the males. (C – F) R6/2 also developed age-related diminished exploration in an open field, detectable from 9 weeks for the males, but at 13 weeks only for the females, however, there were no changes in time spent in the periphery of the arena (thigmotaxis). (G – J) There was no difference in passive avoidance training or memory in 6 week old R6/2 mice. Data presented as means ± SEM; *p<.05, ***p<.001.</p

Progressive rotarod deficits developed simultaneously to a lowering of exploratory activity in R6/2 mice.

<p>Latency to fall from an accelerating rotarod against exploratory activity measured in an open field for all R6/2 mice; data points were separated into the three ages investigated, at 5, 9 and 13 weeks of age. Positive correlations were detected between these two tasks over time due to the simultaneous development of deficits in both male (r = 0.507, **p<.01) and female (r = 0.5, **p<.01) R6/2.</p

MRI assessment of brain volumetry and T2 relaxivity in WT and R6/2.

<p>(A) Regional brain volumes assessed through MRI (volumetry) became progressively smaller in both male and female R6/2 mice versus WT, with the exception of the female R6/2 corpus callosum, which did not differ as compared to WT at any age. (B) T2 relaxation times (T2 relaxivity) progressively shortened for both WT and R6/2 with age, but this was significantly exacerbated in the R6/2 in all regions of interest investigated. Data presented as means ± SEM; males: *p<.05, **p<.01, ***p<.001, females: ^#p<.05, ^##p<.01,^###p<.001.</p

Quantification of mHTT accumulation.

<p>(A) Representative coronal sections from 14 weeks old WT and R6/2 mouse brains stained with the S830 antibody for the detection of mHTT. Levels were quantified within seven brain regions using an intensity threshold-based image analysis tool optimized for the detection of nuclear inclusions, or total levels of mHTT (neuropil aggregates and diffuse nuclear accumulation, highlighted in blue); scale bar 50 µm. Percentage of sampled field of views (FOVs) positive for S830 stain of nuclear inclusions (B), and percentage of FOV positive for total mHTT (C); there were no significant differences between male and female R6/2 for either assessments. Regional differences in mHTT reflect cellular density. STR = striatum, CTX = cortex, HIPP = hippocampus, DG = dentate gyrus, CA1 = hippocampal CA1 subfield, CA2 = hippocampal CA2 subfield, CA3 = hippocampal CA3 subfield. Data presented as means ± SEM.</p