Modelling the Species Distribution of Flat-Headed Cats (Prionailurus planiceps), an Endangered South-East Asian Small Felid

Background

The flat-headed cat (Prionailurus planiceps) is one of the world''s least known, highly threatened felids with a distribution restricted to tropical lowland rainforests in Peninsular Thailand/Malaysia, Borneo and Sumatra. Throughout its geographic range large-scale anthropogenic transformation processes, including the pollution of fresh-water river systems and landscape fragmentation, raise concerns regarding its conservation status. Despite an increasing number of camera-trapping field surveys for carnivores in South-East Asia during the past two decades, few of these studies recorded the flat-headed cat.

Methodology/Principal Findings

In this study, we designed a predictive species distribution model using the Maximum Entropy (MaxEnt) algorithm to reassess the potential current distribution and conservation status of the flat-headed cat. Eighty-eight independent species occurrence records were gathered from field surveys, literature records, and museum collections. These current and historical records were analysed in relation to bioclimatic variables (WorldClim), altitude (SRTM) and minimum distance to larger water resources (Digital Chart of the World). Distance to water was identified as the key predictor for the occurrence of flat-headed cats (>50% explanation). In addition, we used different land cover maps (GLC2000, GlobCover and SarVision LLC for Borneo), information on protected areas and regional human population density data to extract suitable habitats from the potential distribution predicted by the MaxEnt model. Between 54% and 68% of suitable habitat has already been converted to unsuitable land cover types (e.g. croplands, plantations), and only between 10% and 20% of suitable land cover is categorised as fully protected according to the IUCN criteria. The remaining habitats are highly fragmented and only a few larger forest patches remain.

Conclusion/Significance

Based on our findings, we recommend that future conservation efforts for the flat-headed cat should focus on the identified remaining key localities and be implemented through a continuous dialogue between local stakeholders, conservationists and scientists to ensure its long-term survival. The flat-headed cat can serve as a flagship species for the protection of several other endangered species associated with the threatened tropical lowland forests and surface fresh-water sources in this region.     

SEPALLATA3: the 'glue' for MADS box transcription factor complex formation

Background  

Plant MADS box proteins play important roles in a plethora of developmental processes. In order to regulate specific sets of target genes, MADS box proteins dimerize and are thought to assemble into multimeric complexes. In this study a large-scale yeast three-hybrid screen is utilized to provide insight into the higher-order complex formation capacity of the Arabidopsis MADS box family. SEPALLATA3 (SEP3) has been shown to mediate complex formation and, therefore, special attention is paid to this factor in this study.     

IL-1β and TNF-α alter the glycophenotype of primary human chondrocytes in vitro

Despite the significance of glycoproteins for extracellular matrix assembly in cartilage tissue, little is known about the regulation of the chondrocyte glycophenotype under inflammatory conditions. The present study aimed to assess the effect of IL-1β and TNF-α on specific features of the glycophenotype of primary human chondrocytes in vitro. Using LC-MS, we found that both cytokines increased overall sialylation of N- and O-glycans and induced a shift towards α-(2→3)-linked sialic acid residues in chondrocyte glycoproteins. These results were supported by quantitative PCR showing increased expression of α-(2→3) sialyltransferases in treated cells. Moreover, we found that both IL-1β and TNF-α induced a considerable shift from oligomannosidic glycans towards complex-type N-glycans. In contrast, core α-(1→6)-fucosylation of chondrocyte N-glycans was found to be reduced particularly by TNF-α. In summary, inflammatory conditions induce specific alterations of the chondrocyte glycophenotype which might affect cell-matrix interactions or the function of endogenous lectins.     

Structural and cellular features in metaphyseal and diaphyseal periosteum of osteoporotic rats

Despite the important physiological role of periosteum in the pathogenesis and treatment of osteoporosis, little is known about the structural and cellular characteristics of periosteum in osteoporosis. To study the structural and cellular differences in both diaphyseal and metaphyseal periosteum of osteoporotic rats, samples from the right femur of osteoporotic and normal female Lewis rats were collected and tissue sections were stained with hematoxylin and eosin, antibodies or staining kit against tartrate resistant acid phosphatase (TRAP), alkaline phosphatase (ALP), vascular endothelial growth factor (VEGF), von Willebrand (vWF), tyrosine hydroxylase (TH) and calcitonin gene-related peptide (CGRP). The results showed that the osteoporotic rats had much thicker and more cellular cambial layer of metaphyseal periosteum compared with other periosteal areas and normal rats (P < 0.001). The number of TRAP⁺ osteoclasts in bone resorption pits, VEGF⁺ cells and the degree of vascularization were found to be greater in the cambial layer of metaphyseal periosteum of osteoporotic rats (P < 0.05), while no significant difference was detected in the number of ALP⁺ cells between the two groups. Sympathetic nerve fibers identified by TH staining were predominantly located in the cambial layer of metaphyseal periosteum of osteoporotic rats. No obvious difference in the expression of CGRP between the two groups was found. In conclusion, periosteum may play an important role in the cortical bone resorption in osteoporotic rats and this pathological process may be regulated by the sympathetic nervous system.     

Spatial patterns of Bovine Corona Virus and Bovine Respiratory Syncytial Virus in the Swedish beef cattle population

Background  

Both bovine coronavirus (BCV) and bovine respiratory syncytial virus (BRSV) infections are currently wide-spread in the Swedish dairy cattle population. Surveys of antibody levels in bulk tank milk have shown very high nationwide prevalences of both BCV and BRSV, with large variations between regions. In the Swedish beef cattle population however, no investigations have yet been performed regarding the prevalence and geographical distribution of BCV and BRSV. A cross-sectional serological survey for BCV and BRSV was carried out in Swedish beef cattle to explore any geographical patterns of these infections.     

High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability

The traditional view of the nitrogen (N) cycle has been challenged since the discovery that plants can compete with microbes for low molecular weight (LMW) organic N. Despite a number of studies that have shown LMW organic N uptake by plants, there remains a debate on the overall ecological relevance of LMW organic N uptake by plants across ecosystems with different N availabilities. We here report patterns of glycine N uptake by plants from three different Australian land-use types with intermediate N availability and low inherent glycine concentrations in the soil. Using ¹⁵N labeled tracers, we tested the potential of these plants to acquire glycine in ex-situ laboratory experiments and attempted to validate these results in the field by determining actual uptake of glycine by plants directly from the soil. We found in the ex-situ experiments that plants from all three land-use types were able to take up significant amounts of glycine. In contrast, glycine uptake directly from the soil was minimal in all three land-use types and ¹⁵N tracers were largely immobilized in the soil organic N pool. Our study confirms that the potential for LMW organic N uptake by plants is a widespread phenomenon. However, our in-situ experiments show that in the three land-use types tested here plants are inferior competitors for LMW organic N and rely on NH ₄ ⁺ as their main N source. In contrast to several previous studies in arctic, alpine and even temperate ecosystems, our study suggests that in ecosystems with intermediate N availability, mineral N is the plants’ main N source, while LMW organic N is of less ecological relevance to plant N nutrition.     

6-hydroxy-l-nicotine from Arthrobacter nicotinovorans sustain spatial memory formation by decreasing brain oxidative stress in rats

Male Wistar rats were subjected to chronic 6-hydroxy-l-nicotine treatment (6HLN, 0.3 mg/kg, i.p., seven consecutive days) and their memory performance was studied by means of Y-maze and radial arm-maze tasks. 6HLN significantly increased spontaneous alternations in Y-maze task and working memory in radial arm-maze task, suggesting effects on short-term memory, without affecting long-term memory, explored by reference memory in radial arm-maze task. In addition, 6HLN increased antioxidant enzymes activity and decreased production of lipid peroxidation, suggesting antioxidant effects. Also, the linear regression between behavioral measures and oxidative stress markers resulted in significant correlations. Therefore, positive effects of 6HLN on spatial memory may occur by antioxidant actions.     

Local delivery of CpG oligodeoxynucleotides induces rapid changes in the genital mucosa and inhibits replication,but not entry,of herpes simplex virus type 2

Mucosal surfaces are the entry sites for the vast majority of infectious pathogens and provide the first line of defense against infection. In addition to the epithelial barrier, the innate immune system plays a key role in recognizing and rapidly responding to invading pathogens via innate receptors, such as Toll-like receptors (TLR). Bacterial CpG DNA, a potent activator of innate immunity, is recognized by TLR9. Here, we confirm that local mucosal, but not systemic, delivery of CpG oligodeoxynucleotides (ODN) to the genital tract protects mice from a subsequent lethal vaginal herpes simplex virus type 2 (HSV-2) challenge. Since these effects were so local in action, we examined the genital mucosa. Local delivery of CpG ODN induced rapid proliferation and thickening of the genital epithelium and caused significant recruitment of inflammatory cells to the submucosa. Local CpG ODN treatment also resulted in inhibition of HSV-2 replication but had no effect on HSV-2 entry into the genital mucosa. CpG ODN-induced protection against HSV-2 was not associated with early increases in gamma interferon (IFN-gamma) secretion in the genital tract, and CpG ODN-treated IFN-gamma(-/-) mice were protected from subsequent challenge with a lethal dose of HSV-2. Treatment of human HEK-293 cells transfected with murine TLR9 showed that the antiviral activity of CpG ODN was mediated through TLR9. These studies suggest that local induction of mucosal innate immunity can provide protection against sexually transmitted infections, such as HSV-2 or possibly human immunodeficiency virus, at the mucosal surfaces.     

Heme regulates allosteric activation of the Slo1 BK channel

Large conductance calcium-dependent (Slo1 BK) channels are allosterically activated by membrane depolarization and divalent cations, and possess a rich modulatory repertoire. Recently, intracellular heme has been identified as a potent regulator of Slo1 BK channels (Tang, X.D., R. Xu, M.F. Reynolds, M.L. Garcia, S.H. Heinemann, and T. Hoshi. 2003. Nature. 425:531-535). Here we investigated the mechanism of the regulatory action of heme on heterologously expressed Slo1 BK channels by separating the influences of voltage and divalent cations. In the absence of divalent cations, heme generally decreased ionic currents by shifting the channel's G-V curve toward more depolarized voltages and by rendering the curve less steep. In contrast, gating currents remained largely unaffected by heme. Simulations suggest that a decrease in the strength of allosteric coupling between the voltage sensor and the activation gate and a concomitant stabilization of the open state account for the essential features of the heme action in the absence of divalent ions. At saturating levels of divalent cations, heme remained similarly effective with its influence on the G-V simulated by weakening the coupling of both Ca(2+) binding and voltage sensor activation to channel opening. The results thus show that heme dampens the influence of allosteric activators on the activation gate of the Slo1 BK channel. To account for these effects, we consider the possibility that heme binding alters the structure of the RCK gating ring and thereby disrupts both Ca(2+)- and voltage-dependent gating as well as intrinsic stability of the open state.