Red deer (Cervus elaphus) as a host for the cattle tick Rhipicephalus microplus (Acari: Ixodidae) in Yucatan, Mexico

Rhipicephalus microplus is the most economically important cattle tick in the Mexican tropics. Wild ungulate species, including red deer (Cervus elaphus), are gaining popularity in diversified livestock ranching operations in Mexico. However, there is no information available on the susceptibility of red deer to infestation with the cattle tick, R. microplus, under hot, subhumid tropical conditions in Mexico. Biological data on R. microplus as an ectoparasite of cattle and red deer in a farm in the Mexican tropics are presented here. Ticks collected from red deer were identified as R. microplus (97 %) and Amblyomma cajennense (3 %), and tick species infesting cattle included R. microplus (95 %) and A. cajennense (5 %). Standard counts of R. microplus engorged females on red deer were 11 times higher than on cattle (428 ± 43 vs. 40 ± 18; p < 0.001). The reproductive efficiency index and larval hatching of R. microplus collected from cattle and red deer were similar (p > 0.05). Hemolymph samples of R. microplus collected from cattle were positive for Babesia spp. (10 %, 2/50) and all the samples from ticks infesting red deer were negative. Seventeen and ten percent of the blood samples from cattle and red deer were positive for Anaplasma marginale, respectively. The role of red deer as a host of R. microplus in Yucatan, Mexico and the importance of this host-parasite relationship relative to the epidemiology of R. microplus-borne diseases are discussed.     

Photosynthetic and respiratory responses of Gracilaria parvispora from the southeastern Gulf of California

Photosynthetic and respiratory responses (P–E curves) of Gracilaria parvispora from the southeast Gulf of California were studied at four temperatures (20, 25, 30, 35 °C) and salinity (25, 30, 35, 40 psu) combinations. The alga showed acclimation in its photosynthetic and respiratory responses to tropical temperature as well as to oceanic salinity. A positive effect of temperature on photosynthetic rate (P _max) was observed for all salinities. Photosynthetic rates for treatments at 20 and 25 °C were lower (<9.2 mg O₂?g dry weight (dw)^?1?h^?1) than for treatments at 30 and 35 °C (>12 mg O₂ g dw^?1?h^?1). G. parvispora showed limited tolerance to low salinities (25 psu) and low temperatures (20 °C) and the interaction between temperature and salinity was significant (analysis of variance, P?<?0.05). Responses to salinity indicated adaptation to oceanic salinity. Photosynthetic responses were lower at 25 psu than at higher salinities. The lowest P _max values (6.2–8.2 mg O₂?g dw^?1?h^?1) were observed at the lowest salinity (25 psu) regardless of temperature. Compensation and saturation irradiances (26–170 and 57–149 μmol photons m^?2?s^?1, respectively) indicate adaptation to lower irradiances in shallow (1–2 m depth) habitats, where turbidity can be high, and the capacity of shade adaptation has been developed. Results suggest distribution of this species is mainly related to salinity or temperature. The potential mariculture efforts of G. parvispora would be limited by low temperatures in winter, and indicate that this species will probably not be able to spread further due to low temperatures (<15 °C) in the upper part of the Gulf of California.     

D6PK AGCVIII Kinases Are Required for Auxin Transport and Phototropic Hypocotyl Bending in Arabidopsis

Phototropic hypocotyl bending in response to blue light excitation is an important adaptive process that helps plants to optimize their exposure to light. In Arabidopsis thaliana, phototropic hypocotyl bending is initiated by the blue light receptors and protein kinases phototropin1 (phot1) and phot2. Phototropic responses also require auxin transport and were shown to be partially compromised in mutants of the PIN-FORMED (PIN) auxin efflux facilitators. We previously described the D6 PROTEIN KINASE (D6PK) subfamily of AGCVIII kinases, which we proposed to directly regulate PIN-mediated auxin transport. Here, we show that phototropic hypocotyl bending is strongly dependent on the activity of D6PKs and the PIN proteins PIN3, PIN4, and PIN7. While early blue light and phot-dependent signaling events are not affected by the loss of D6PKs, we detect a gradual loss of PIN3 phosphorylation in d6pk mutants of increasing complexity that is most severe in the d6pk d6pkl1 d6pkl2 d6pkl3 quadruple mutant. This is accompanied by a reduction of basipetal auxin transport in the hypocotyls of d6pk as well as in pin mutants. Based on our data, we propose that D6PK-dependent PIN regulation promotes auxin transport and that auxin transport in the hypocotyl is a prerequisite for phot1-dependent hypocotyl bending.     

Prevalence of Lawsonia intracellularis, Brachyspira hyodysenteriae, and Brachyspira pilosicoli infection in hunted wild boars (Sus scrofa) in Germany

Lawsonia intracellularis, Brachyspira hyodysenteriae, and Brachyspira pilosicoli are important pathogens in domestic pig production, responsible for porcine intestinal adenomatosis, swine dysentery, and porcine intestinal spirochetosis, respectively. They are widely distributed among pig-producing units around the world, and transmission is accomplished by relatively weak immunity, long shedding intervals, sequential shedding, and actual environmental survival. Little information is available on occurrence, prevalence, and quantity of these pathogens in free-ranging wild boars. The aim of the present study was to evaluate L. intracellularis, B. hyodysenteriae, and B. pilosicoli infections in wild boars in Germany. Tissue samples from ileocaecal mucosa of 165 wild boars from 18 hunting grounds situated in 14 of the 16 federal states of Germany were examined by conventional PCR and quantified by multiplex real-time PCR. None of the wild boars did show any gross pathological signs of enteritis. The overall prevalence for L. intracellularis, B. hyodysenteriae, and B. pilosicoli was 20.6%, 2.4%, and 12.1%, respectively. None of the three agents was detected in 68.5% of the wild boars and in 11.1% of the hunting grounds. Numbers of bacteria per sample were below the limit of quantification (100 cells/PCR reaction). This is the first study on L. intracellularis and Brachyspira spp. in free-ranging wild boars. The study revealed colonised animals without signs of disease. The meaning of these findings remains unclear, and we do not know whether and to what extent these three pathogens are exchanged between wild boars and domestic pigs. Further research is needed to get insight into the epidemiological impact of the results.     

Plant Hsp90 proteins interact with B-cells and stimulate their proliferation

Background

The molecular chaperone heat shock protein 90 (Hsp90) plays an important role in folding stabilization and activation of client proteins. Besides, Hsp90 of mammals and mammalian pathogens displays immunostimulatory properties. Here, we investigated the role of plant-derived Hsp90s as B-cell mitogens by measuring their proliferative responses in vitro.

Methodology

Plant cytosolic Hsp90 isoforms from Arabidopsis thaliana (AtHsp81.2) and Nicotiana benthamiana (NbHsp90.3) were expressed in E. coli. Over-expression of recombinant plant Hsp90s (rpHsp90s) was confirmed by SDS-PAGE and western blot using and anti-AtHsp81.2 polyclonal anti-body. Both recombinant proteins were purified by Ni-NTA affinity chromatography and their identity confirmed by MALDI-TOF-TOF. Recombinant AtHsp81.2 and NbHsp90.3 proteins induced prominent proliferative responses in spleen cells form BALB/c mice. Polymyxin-B, a potent inhibitor of lipopolysaccharide (LPS), did not eliminate the rpHsp90-induced proliferation. In addition, in vitro incubation of spleen cells with rpHsp90 led to the expansion of CD19-bearing populations, suggesting a direct effect of these proteins on B lymphocytes. This effect was confirmed by immunofluorescence analysis, where a direct binding of rpHsp90 to B- but not to T-cells was observed in cells from BALB/c and C3H/HeN mice. Finally, we examined the involvement of Toll Like Receptor 4 (TLR4) molecules in the rpHsp90s induction of B-cell proliferation. Spleen cells from C3H/HeJ mice, which carry a point mutation in the cytoplasmic region of TLR4, responded poorly to prAtHsp90. However, the interaction between rpHsp90 and B-cells from C3H/HeJ mice was not altered, suggesting that the mutation on TLR4 would be affecting the signal cascade but not the rpHsp90-TLR4 receptor interaction.

Conclusions

Our results show for the first time that spleen cell proliferation can be stimulated by a non-pathogen-derived Hsp90. Furthermore, our data provide a new example of a non-pathogen-derived ligand for TLRs.     

Three-dimensional imaging of the mouse neurovasculature with magnetic resonance microscopy

Knowledge of the three-dimensional (3D) architecture of blood vessels in the brain is crucial because the progression of various neuropathologies ranging from Alzheimer's disease to brain tumors involves anomalous blood vessels. The challenges in obtaining such data from patients, in conjunction with development of mouse models of neuropathology, have made the murine brain indispensable for investigating disease induced neurovascular changes. Here we describe a novel method for "whole brain" 3D mapping of murine neurovasculature using magnetic resonance microscopy (μMRI). This approach preserves the vascular and white matter tract architecture, and can be combined with complementary MRI contrast mechanisms such as diffusion tensor imaging (DTI) to examine the interplay between the vasculature and white matter reorganization that often characterizes neuropathologies. Following validation with micro computed tomography (μCT) and optical microscopy, we demonstrate the utility of this method by: (i) combined 3D imaging of angiogenesis and white matter reorganization in both, invasive and non-invasive brain tumor models; (ii) characterizing the morphological heterogeneity of the vascular phenotype in the murine brain; and (iii) conducting "multi-scale" imaging of brain tumor angiogenesis, wherein we directly compared in vivo MRI blood volume measurements with ex vivo vasculature data.