Lignified and nonlignified fiber cables in the lacunae of <Emphasis Type="Italic">Typha angustifolia</Emphasis>

The leaves of Typha are noteworthy in terms of their mechanical properties. We determined the mechanical properties of the fiber cables within the leaf. We found that in vegetative plants, the lignified fiber cables isolated from the leaf sheath and nonlignified fiber cables isolated from the leaf blade of Typha angustifolia differ in their diameter, swelling capacity, Young’s modulus, tensile strength, and break load. These differing properties are related to their contributions to stability in the two regions of the leaf.     

Dim light at night prior to adolescence increases adult anxiety-like behaviors

Dim light at night (dLAN) disrupts circadian organization and influences adult behavior. We examined early dLAN exposure on adult affective responses. Beginning 3 (juvenile) or 5 weeks (adolescent) of age, mice were maintained in standard light–dark cycles or exposed to nightly dLAN (5 lx) for 5 weeks, then anxiety-like and fear responses were assessed. Hypothalami were collected around the clock to assess core clock genes. Exposure to dLAN at either age increased anxiety-like responses in adults. Clock and Rev-ERB expression were altered by exposure to dLAN. In contrast to adults, dLAN exposure during early life increases anxiety and fear behavior.     

Conditional gene inactivation by combining tetracycline-mediated transcriptional repression and auxin-inducible degron-mediated degradation

Characterizing the functions of essential cell cycle control genes requires tight and rapid inducible gene inactivation. Drawbacks of current conditional depletion approaches include slow responses and incomplete depletion. We demonstrated that by integrating the tetracycline-controlled promoter system and the auxin-inducible degron (AID) system together, AID-tagged proteins can be downregulated more efficiently than the individual technology alone. When used in conjunction with CRISPR-Cas9-mediated disruption of the endogenous locus, this system facilitates the analysis of essential genes by allowing rapid and tight conditional depletion, as we have demonstrated using several cell cycle-regulatory genes including cyclin A, CDK2, and TRIP13. The vectors constructed in this study allow expression of AID-fusion proteins under the control of tetracycline-controlled promoters and should be useful in studies requiring rapid and tight suppression of gene expression in mammalian cells.     

Vaccinia virus infection induces dendritic cell maturation but inhibits antigen presentation by MHC class II

Vaccinia virus (VV) infection is known to inhibit dendritic cells (DC) functions in vitro. Paradoxically, VV is also highly immunogenic and thus has been used as a vaccine. In the present study, we investigated the effects of an in vivo VV infection on DC function by focusing on early innate immunity. Our data indicated that DC are activated upon in vivo VV infection of mice. Splenic DC from VV-infected mice expressed elevated levels of MHC class I and co-stimulatory molecules on their cell surface and exhibited the enhanced potential to produce cytokines upon LPS stimulation. DC from VV-infected mice also expressed a high level of interferon-beta. However, a VV infection resulted in the down-regulation of MHC class II expression and the impairment of antigen presentation to CD4 T cells by DC. Thus, during the early stage of a VV infection, although DC are impaired in some of the critical antigen presentation functions, they can promote innate immune defenses against viral infection.     

Spatial phylogenetics of the Chinese angiosperm flora provides insights into endemism and conservation

The flora of China is well known for its high diversity and endemism. Identifying centers of endemism and designating conservation priorities are essential goals for biodiversity studies. However, there is no comprehensive study from a rigorous phylogenetic perspective to understand patterns of diversity and endemism and to guide biodiversity conservation in China. We conducted a spatial phylogenetic analysis of the Chinese angiosperm flora at the generic level to identify centers of neo- and paleo-endemism. Our results indicate that: (i) the majority of grid cells in China with significantly high phylogenetic endemism (PE) were located in the mountainous regions; (ii) four of the nine centers of endemism recognized, located in northern and western China, were recognized for the first time; (iii) arid and semiarid regions in Northwest China were commonly linked to significant PE, consistent with other spatial phylogenetic studies worldwide; and (iv) six high-priority conservation gaps were detected by overlaying the boundaries of China's nature reserves on all significant PE cells. Overall, we conclude that the mountains of southern and northern China contain both paleo-endemics (ancient relictual lineages) and neo-endemics (recently diverged lineages). The areas we highlight as conservation priorities are important for broad-scale planning, especially in the context of evolutionary history preservation.     

Do phytogeographic patterns reveal biomes or biotic regions?

We present the largest comparative biogeographical analysis that has complete coverage of Australia's geography (20 phytogeographical subregions), using the most complete published molecular phylogenies to date of large Australian plant clades (Acacia, Banksia and the eucalypts). Two distinct sets of areas within the Australian flora were recovered, using distributional data from the Australasian Virtual Herbarium (AVH) and the Atlas of Living Australia (ALA): younger Temperate, Eremaean and Monsoonal biomes, and older southwest + west, southeast and northern historical biogeographical regions. The analyses showed that by partitioning the data into two sets, using either a Majority or a Frequency method to select taxon distributions, two equally valid results were found. The dataset that used a Frequency method discovered general area cladograms that resolved patterns of the Australian biomes, whereas if widespread taxa (Majority method, with >50% of occurrences outside a single subregion) were removed the analysis then recovered historical biogeographical regions. The study highlights the need for caution when processing taxon distributions prior to analysis as, in the case of the history of Australian phytogeography, the validity of both biomes and historical areas have been called into question.     

Temperature and hemodynamic changes associated with increased neural damage to global hemispheric hypoxic ischemia by prior prostaglandin E2, D2 and F2alpha administration

Experiments compared the hemispheric neural damage resulting from global hemispheric hypoxic ischemia (GHHI, ligation of right common carotid artery plus 35 min of 12% O2) in groups of anesthetized, male Long Evans rats, 9-10 weeks of age, kept at 37 degrees C, and previously given an intracerebroventricular (i.c.v., 2.5 microl) injection of 28 or 70 pmoles of PGE2, PGF2alpha or PGD2 or sterile saline (SS) 30 min beforehand. Mean arterial pressure (MAP), ipsilateral cortical capillary blood flow (CBF), colonic (Tc), ipsilateral (Tipsi) and contralateral (Tcontra), temporalis muscle temperatures were measured before, during and for 15 min after GHHI. Necrotic neural damage was assessed 7 days post-GHHI. All groups given GHHI + PGs showed increased ipsilateral hemispheric damage to GHHI especially due to enhanced neocortical damage, compared to the saline control group given the same insult. PGD2 was the most potent PG to cause further damage to the global insult. Tc, Tipsi, Tcontra and MAP increased following the i.c.v. injection of PGE2. I.c.v. PGF2alpha transiently decreased MAP, PGD2 tended to decrease cerebral blood flow and neither evoked changes in temperature compared to respective pre-injection control values. Results demonstrate increased neural damage to GHHI with prior i.c.v. PGE2, PGF2alpha or PGD2 administration.