Adiponectin in the mammalian host influences ticks' acquisition of the Lyme disease pathogen Borrelia.

Arthropod-borne pathogens cause some of the most important human and animal infectious diseases. Many vectors acquire or transmit pathogens through the process of blood feeding. Here, we report adiponectin, the most abundant adipocyte-derived hormone circulating in human blood, directly or indirectly inhibits acquisition of the Lyme disease agent, Borrelia burgdorferi, by Ixodes scapularis ticks. Rather than altering tick feeding or spirochete viability, adiponectin or its associated factors induces host histamine release when the tick feeds, which leads to vascular leakage, infiltration of neutrophils and macrophages, and inflammation at the bite site. Consistent with this, adiponectin-deficient mice have diminished pro-inflammatory responses, including interleukin (IL)-12 and IL-1ß, following a tick bite, compared with wild-type animals. All these factors mediated by adiponectin or associated factors influence B. burgdorferi survival at the tick bite site. These results suggest a host adipocyte-derived hormone modulates pathogen acquisition by a blood-feeding arthropod.

IL-10 Deficiency Protects Hamsters from Leptospira Infection.

Leptospirosis is a global zoonotic disease with outcomes ranging from subclinical infection to fatal Weil's syndrome. In addition to antibiotics, some immune activators have shown protective effects against leptospirosis. However, the unclear relationship between Leptospira and cytokines has limited the development of antileptospiral immunomodulators. In this study, the particular role of interleukin-10 (IL-10) in leptospirosis was explored by using IL-10-defective (IL-10-/-) hamsters. After Leptospira infection, an improved survival rate, reduced leptospiral burden, and alleviation of organ lesions were found in IL-10-/- hamsters compared with wild-type (WT) hamsters. In addition, the levels of expression of the IL-1ß, IL-6, and tumor necrosis factor alpha (TNF-α) genes and the level of nitric oxide (NO) were higher in IL-10-/- hamsters than in WT hamsters. Our results indicate that IL-10 deficiency protects hamsters from Leptospira infection.

A human secretome library screen reveals a role for Peptidoglycan Recognition Protein 1 in Lyme borreliosis.

Lyme disease, the most common vector-borne illness in North America, is caused by the spirochete Borrelia burgdorferi. Infection begins in the skin following a tick bite and can spread to the hearts, joints, nervous system, and other organs. Diverse host responses influence the level of B. burgdorferi infection in mice and humans. Using a systems biology approach, we examined potential molecular interactions between human extracellular and secreted proteins and B. burgdorferi. A yeast display library expressing 1031 human extracellular proteins was probed against 36 isolates of B. burgdorferi sensu lato. We found that human Peptidoglycan Recognition Protein 1 (PGLYRP1) interacted with the vast majority of B. burgdorferi isolates. In subsequent experiments, we demonstrated that recombinant PGLYRP1 interacts with purified B. burgdorferi peptidoglycan and exhibits borreliacidal activity, suggesting that vertebrate hosts may use PGLYRP1 to identify B. burgdorferi. We examined B. burgdorferi infection in mice lacking PGLYRP1 and observed an increased spirochete burden in the heart and joints, along with splenomegaly. Mice lacking PGLYRP1 also showed signs of immune dysregulation, including lower serum IgG levels and higher levels of IFNγ, CXCL9, and CXCL10.Taken together, our findings suggest that PGLYRP1 plays a role in the host's response to B. burgdorferi and further demonstrate the utility of expansive yeast display screening in capturing biologically relevant interactions between spirochetes and their hosts.

Norfloxacin suppresses Leptospira-induced inflammation through inhibiting p65 and ERK phosphorylation and NLRP3 inflammasome activation.

Leptospirosis is a worldwide re-emerging zoonosis caused by pathogenic Leptospira. Inflammatory storms induced by Leptospira are the reason to induce immunoparalysis and organ failures. Antibiotics are still the current mainstream treatment for leptospirosis. In addition to their antibacterial action, the immunomodulatory function of antibiotics has been paid more and more attention. In this study, the role of norfloxacin on Leptospira-induced inflammation was investigated. Treatment with norfloxacin down-regulated Leptospira-induced IL-1ß and TNF-α both in vivo and vitro models. Further study showed that norfloxacin inhibited Leptospira-induced phosphorylation of p65 and ERK. Norfloxacin also inhibited the Leptospira-induced NLRP3 inflammasome activation with the increased level of Na/K-ATPase Pump ß1 subunit and decreased level of Kcnk6. These results indicated that norfloxacin suppressed Leptospira-induced inflammation through inhibiting p65 and ERK phosphorylation and NLRP3 inflammasome activation. Norfloxacin may be a potential candidate for suppressing inflammatory storms caused by Leptospira.

Immune-enhanced effect of Iris polysaccharide is protective against leptospirosis.

Leptospirosis, caused by pathogenic Leptospira species, is an essential but neglected zoonosis. There are more than 300 serovars of pathogenic Leptospira, while inactivated bacteria offers only short-term serovar-specific protection. Leptospirosis treatment is mainly dependent on the use of antibiotics. However, the side effects of antibiotics and the risk of antibiotic resistance remain major problems. Thus, alternative agents which are fewer side effects on humans and efficient in leptospirosis would be welcome. Many studies have reported that polysaccharides could be used as immunostimulants in treating infection and cancer. In this study, we examined the protective effect of polysaccharides isolated from Iris against leptospirosis. To our knowledge, it is the first time to report Iris polysaccharides (IP) as an immunostimulant in treating infection. The results showed that IP treatment significantly increased the survival rate of hamsters challenged by a lethal dose of leptospires. Besides, the tissue injury and leptospiral load were reduced in IP-treated infection group compared with the untreated infection group at 4 days post-infection (p.i.). Intriguingly, IP treatment sustained intense immune response at 4 days p.i. analyzed by qPCR. The results exhibited that the gene expression of TLR2 and TLR4 was significantly increased in the group coinjected with IP and leptospires than in the infected controls. And the expression of IL-1ß and TNF-α were also up-regulated after IP treatment, except the expression of IL-1ß in the kidney. Our results not only broaden the medicinal value of Iris, but also provide a competent candidate for the control of Leptospira infection.

Emergency vaccine immunization protects hamsters against acute leptospirosis.

Leptospirosis, caused by pathogenic Leptospira, is a global critical zoonotic disease in terms of mortality and morbidity. Vaccines are often used to prevent leptospirosis. However, few studies have reported the therapeutic effect of a vaccine against Leptospira infection. This study demonstrates the efficacy of the emergency vaccine immunization against acute leptospirosis in hamsters. Treatment with a whole-cell vaccine (Leptospira interrogans serovar Lai) at 24 h post-infection improved the survival rate of hamsters with lower leptospiral burden and minor pathological damage to organs. The vaccine also protected against multiple Leptospira serotypes acute infection. However, the protective effect of the vaccines was lost when beginning treatment at 36 h or 48 h post-infection. These results indicated that vaccines could treat acute leptospirosis in hamsters, but only if immunization is within 24 h after infection.

Dipotassium glycyrrhizinate relieves leptospira-induced nephritis in vitro and in vivo.

Chronic leptospirosis usually occurs during sublethal doses infection of susceptible animal and reservoir host, which typical symptom is interstitial nephritis, and leptospira urine, contaminating the environment and threatening other susceptible animals and humans. Dipotassium glycyrrhizinate (DG) is a replacement for glycyrrhizic acid, which exhibits anti-inflammation, immunomodulation effects. This study is to investigate whether DG relieves leptospira-induced nephritis. In vitro, DG inhibited the leptospira-induced transcription levels of IL-1ß, IL-6, TNF-α, RANTES, MCP-1 and iNOS, and protein levels of IL-1ß and TNF-α, and downregulated NF-κB and MAPK pathway in TCMK-1 cells. In vivo, DG attenuated the kidney histopathological change and downregulated the expression of IL-1ß and TNF-α, as well as reduced kidney leptospiral burden. In summary, DG alleviated leptospira-induced inflammation through inhibitory NF-κB and MAPK pathway, and DG decreased the renal colonization of leptospires in mice.

An Ixodes scapularis Protein Disulfide Isomerase Contributes to Borrelia burgdorferi Colonization of the Vector.

Borrelia burgdorferi causes Lyme disease, the most common tick-transmitted illness in North America. When Ixodes scapularis feed on an infected vertebrate host, spirochetes enter the tick gut along with the bloodmeal and colonize the vector. Here, we show that a secreted tick protein, I. scapularisprotein disulfide isomerase A3 (IsPDIA3), enhances B. burgdorferi colonization of the tick gut. I. scapularis ticks in which ispdiA3 has been knocked down using RNA interference have decreased spirochete colonization of the tick gut after engorging on B. burgdorferi-infected mice. Moreover, administration of IsPDIA3 antiserum to B. burgdorferi-infected mice reduced the ability of spirochetes to colonize the tick when feeding on these animals. We show that IsPDIA3 modulates inflammatory responses at the tick bite site, potentially facilitating spirochete survival at the vector-host interface as it exits the vertebrate host to enter the tick gut. These data provide functional insights into the complex interactions between B. burgdorferi and its arthropod vector and suggest additional targets to interfere with the spirochete life cycle.

Sodium butyrate alleviates lipopolysaccharide-induced endometritis in mice through inhibiting inflammatory response.

Endometritis is commonly occurred in dairy cows after calving and results in a great deal of property damage. Although numerous studies have been performed to find the therapeutic agents for endometritis, the incidence of this disease remains high. Short-chain fatty acids (SCFAs), the major metabolic products of anaerobic bacteria fermentation in the gut, have been reported to exhibit anti-inflammatory properties. Therefore, the purpose of this study was to investigate the protective effects and mechanisms of sodium butyrate (SB) on lipopolysaccharide (LPS)-induced endometritis in mice. The mice were administered by intraperitoneal injection of SB at 1 h before LPS injection. 24 h later, the uterus tissues were collected. Hematoxylin and eosin (H & E) stained sections of uterus were used to determine the degree of the damage. Uterine myeloperoxidase (MPO) activity was used to analyze neutrophil granulocytes concentration. The levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) were measured by ELISA. The activation of the NF-κB signaling pathway proteins were detected by Western blot analysis. The results showed that SB significantly attenuated the pathological injury of the uterus tissues. SB also suppressed LPS-induced MPO activity and the production of inflammatory cytokines TNF-α and IL-1ß. Furthermore, Western blot analysis showed that SB inhibited the activation of NF-κB signaling pathway. In addition, SB could inhibit histone deacetylases. In summary, SB protects against LPS-induced endometritis through HDAC inhibition.

Dimethyl itaconate protects against lippolysacchride-induced mastitis in mice by activating MAPKs and Nrf2 and inhibiting NF-κB signaling pathways.

Mastitis, as the main disease to affect the dry dairy cow with the characterized by increasing number of somatic cells in milk and reducing milk production, has been known as one of the most serious expensive disease for the dairy industry. Escherichia coli (E.coli), a gram negative bacterial, have normally been considered to be an opportunistic pathogen that can invade the mammary gland sometimes to cause inflammatory diseases. Lippolysacchride (LPS), as the co-cell wall component of the Escherichia coli (E.coli), is the main virulence factors to induce acute inflammation. Itaconate is an endogenous metabolite which has recently been reported to regulate the macrophage function and has the ability to reduce the secretion of pro-inflammatory cytokines, such as IL-6 and IL-12. Here, the aim of this study is to investigate the protective role of dimethyl itaconate (DI)-the membranepermeable derivative of itaconate, on LPS-induced mastitis in mice. To establish the model of mastitis, mice 5-7 day after delivery were utilized by nipple duct injection of LPS, while DI was treated 24h intraperitoneally before LPS injection. Further, the hematoxylin-eosin (H&E) staining was used to evaluate the pathological changes of the mammary gland, the inflammatory cytokines of TNF-α and IL-1ß and the myeloperoxidase (MPO) activity were also measured respectively by enzyme-linked immunosorbent assay (ELISA) and MPO assay kit. To clarify the underling mechanisms of the protective role of DI on mastitis, the MAPKs, NF-κB and Nrf2 signaling pathways were detected via western blotting. The results demonstrated that DI markedly decreased the pathological injury of mammary, and considerably reduced the production of TNF-α and IL-1ß, as well as up-regulated the Nrf2, HO-1, phosphorylation of p38 and ERK, but down-regulated TLR4 and phosphorylation of p65 NF-κB. Our research recommended that DI ameliorated LPS-induced mastitis which highlights itaconate may as a potential candidate to protect against mastitis.

Low-dose Norfloxacin-treated leptospires induce less IL-1ß release in J774A.1 cells following discrepant leptospiral gene expression.

Currently, accumulating evidence is challenging subtherapeutic therapy. Low-dose Norfloxacin (Nor) has been reported to suppress the immune response and worsen leptospirosis. In this study, we investigated the influence of low-dose Nor (0.03 µg/ml, 0.06 µg/ml, 0.125 µg/ml) on leptospiral gene expression and analyzed the immunomodulatory effects of low-dose Nor-treated leptospires in J774A.1 cells. To study the expression profiles of low-dose Nor-treated leptospires, we chose LipL71/LipL21 as reference genes determined by the geNorm applet in this experiment. The results showed that low-dose Nor up-regulated the expression of FlaB and inhibited the expression of 16S rRNA, LipL32, LipL41, Loa22, KdpA, and KdpB compared with the untreated leptospires. These results indicated that low-dose Nor could regulate leptospiral gene expression. Using RT-PCR, the gene expression of IL-1ß and TNF-α in J774A.1 cells was detected. Nor-treated leptospires induced higher expression levels of both IL-1ß and TNF-α. However, when analyzed by ELISA, the release of mature IL-1ß was reduced compared with that observed in cells induced with no Nor-treated leptospires, although the TNF-α protein level showed no significant change. Our study indicated that the gene expression of leptospires could be modulated by low-dose Nor, which induced less IL-1ß release in J774A.1 cells.

Low-dose norfloxacin and ciprofloxacin therapy worsen leptospirosis in hamster.

Antibiotics play an important role in the treatment of leptospirosis. Many antibiotics at appropriate concentrations improved the survival rate and alleviated tissue injury, while, when dosing strategies fall below subtherapeutic levels, worse therapeutic effects are seen. In the present study, we investigated the efficacy of low-dose norfloxacin (10, 20 and 30 mg/kg) and ciprofloxacin (1, 2 and 5 mg/kg) against leptospirosis in a hamster model using Leptospira interrogans serovar Icterohaemorrhagiae. The histopathology and bacterial loads of target organs (liver, kidney and lung) were also studied by treatment with norfloxacin at the dose of 10 mg/kg in this model. Using RT-PCR, the expression of inflammatory factor IL-1ß and TNF-α was analyzed by comparing the norfloxacin and untreated group. All untreated animals, serving as a negative control, displayed 50% survival rate, while hamsters treated with norfloxacin at the dose of 10 and 20 mg/kg and ciprofloxacin at the dose of 1 and 2 mg/kg showed a lower survival rate than the untreated group. Furthermore, norfloxacin at the dose of 10 mg/kg increased bacterial loads and aggravated tissue injury of target organs. The delayed induction of IL-1ß and TNF-α was found in tissues of norfloxacin group. Our study indicates an increased risk associated with low-dose norfloxacin and ciprofloxacin in leptospirosis.

Porcine Viperin protein inhibits the replication of classical swine fever virus (CSFV) in vitro.

BACKGROUND: Classical swine fever virus (CSFV) is the causative pathogen of Classical swine fever (CSF), a highly contagious disease of swine. Viperin is one of the hundreds of interferon-stimulated genes (ISGs), and possesses a wide range of antiviral activities. The aim of this study was to explore whether porcine Viperin has the anti-CSFV activity. METHOD: The influences of CSFV infection on Viperin expression and Newcastle disease virus (NDV)/Pseudorabies virus (PRV)-induced Viperin expression were examined in 3D4/21 cells and porcine peripheral blood mononuclear cells (PBMCs). Porcine Viperin gene was amplified to generate cell line PK-Vi over-expressing Viperin. CSFV was inoculated in the cell lines and viral load was detected by qRT-PCR, virus titration and Western blot. The influence of Viperin expression on CSFV binding, entry and release in the cells was also examined. The co-localization of Viperin with CSFV and its proteins (E2, NS5B) was determined by confocal laser scanning microscopy test. Co-IP assay was performed to check the interaction of Viperin with CSFV proteins. RESULTS: CSFV infection could not induce Viperin expression in vitro while significantly inhibiting NDV/PRV-induced Viperin expression at 12, 24 and 48 h post infection (hpi; P < 0.05). The proliferation of CSFV in PK-Vi was significantly inhibited at 24, 48 and 72 hpi (P < 0.05), comparing with control cells (PK-C1 expressing EGFP). Virus in both cell culture supernatants and cell pellets were reduced equally. CSFV binding and entry in the cells were not interfered by Viperin expression. These results indicated its anti-CSFV function occurred during the genome and/or protein synthesis step. Confocal laser scanning microscopy test showed the Viperin-EGFP protein co-localized with CSFV E2 protein in CSFV infected PK-Vi cells. Further experiments indicated that Viperin protein co-localized with E2 and NS5B proteins of CSFV in the transfected 293 T cells. Furthermore, Co-IP assay confirmed the interaction of Viperin with E2 protein, but not NS5B. CONCLUSION: Porcine Viperin effectively inhibited CSFV replication in vitro, potentially via the interaction of Viperin with CSFV E2 protein in cytoplasm. The results provided foundation for further studies of the interaction of Viperin with CSFV and other viruses.

Toll-Like Receptor 2 Agonist Pam3CSK4 Alleviates the Pathology of Leptospirosis in Hamster.

Leptospirosis, caused by pathogenic spirochetes, is a zoonotic disease of global importance. The detailed pathogenesis of leptospirosis is still unclear, which limits the ideal treatment of leptospirosis. In this study, we analyzed the expression of Toll-like receptor 2 (TLR2) and TLR4 in target organs of both resistant mice and susceptible hamsters after Leptospira interrogans serovar Autumnalis infection. TLR2 but not TLR4 transcripts in mouse organs contrasted with delayed induction and overexpression in hamster organs. Coinjection of leptospires and the TLR2 agonist Pam3CSK4 into hamsters improved their survival rate, alleviated tissue injury, and decreased the abundance of leptospires in target organs. The production of interleukin-10 (IL-10) from tissues was enhanced in hamsters of the group coinjected with leptospires and Pam3CSK4 compared with the leptospira-injected group. Similarly, IL-10 levels in TLR2-deficient mice were lower than those in wild-type mice. A high ratio of IL-10/tumor necrosis factor alpha (TNF-α) levels was found in both infected wild-type mice and hamsters coinjected with leptospires and Pam3CSK4. Moreover, TLR2-dependent IL-10 expression was detected in peritoneal macrophages after leptospira infection. Our data demonstrate that coinjection of leptospires and Pam3CSK4 alleviates the pathology of leptospirosis in hamsters; this effect may result from the enhanced expression of TLR2-dependent IL-10.

FRIENDLY regulates mitochondrial distribution, fusion, and quality control in Arabidopsis.

Mitochondria are defining components of most eukaryotes. However, higher plant mitochondria differ biochemically, morphologically, and dynamically from those in other eukaryotes. FRIENDLY, a member of the CLUSTERED MITOCHONDRIA superfamily, is conserved among eukaryotes and is required for correct distribution of mitochondria within the cell. We sought to understand how disruption of FRIENDLY function in Arabidopsis (Arabidopsis thaliana) leads to mitochondrial clustering and the effects of this aberrant chondriome on cell and whole-plant physiology. We present evidence for a role of FRIENDLY in mediating intermitochondrial association, which is a necessary prelude to mitochondrial fusion. We demonstrate that disruption of mitochondrial association, motility, and chondriome structure in friendly affects mitochondrial quality control and leads to mitochondrial stress, cell death, and strong growth phenotypes.

Target of rapamycin signaling regulates metabolism, growth, and life span in Arabidopsis.

Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis.

Effects of niacin on Staphylococcus aureus internalization into bovine mammary epithelial cells by modulating NF-κB activation.

Niacin is a precursor of coenzymes NAD and NADP and plays a critical role in electron transfer during the metabolic process. In addition to its nutrimental function, niacin has long been used for the treatment of lipid disorders and cardiovascular disease. However, the effect of niacin on Staphylococcus aureus (S. aureus) internalization into bovine mammary epithelial cells (bMEC) remains unclear. Here we sought to examine the effect of niacin on S. aureus internalization into bovine mammary epithelial cells (bMEC) and to investigate the potential mechanism. In this study, the growth of S. aureus supplemented with niacin (0.5-2 mM) was monitored turbidimetrically at 600 nm for 24 h and cell viability was measured by MTT assay. Gentamicin protection assay was carried out to determine the effect of niacin on S. aureus internalization into bMEC. To determine the potential mechanism, tracheal antimicrobial peptide (TAP) and ß-defensin (BNBD5) expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The activation of nuclear factor-kappa B (NF-κB) was determined by Western blotting. The results showed that niacin (0.5-2 mM) did not affect S. aureus growth and bMEC viability, whereas it inhibits S. aureus internalization ranging from 13% to 42% and down-regulated the mRNA expression of TAP and BNBD5 compared to the control group. No exactly relationship was discovered between S. aureus internalization into bMEC and antimicrobial peptide expression, while niacin inhibited S. aureus-induced NF-κB activation in a dose manner. These dates suggest that inhibiting NF-κB activation may be the potential mechanism of niacin on modulating S. aureus internalization into bMEC.

Leptospira interrogans induces uterine inflammatory responses and abnormal expression of extracellular matrix proteins in dogs.

Leptospira interrogans (L. interrogans), a worldwide zoonosis, infect humans and animals. In dogs, four syndromes caused by leptospirosis have been identified: icteric, hemorrhagic, uremic (Stuttgart disease) and reproductive (abortion and premature or weak pups), and also it caused inflammation. Extracellular matrix (ECM) is a complex mixture of matrix molecules that is crucial to the reproduction. Both inflammatory response and ECM are closed relative to reproductive. The aim of this study was to clarify how L. interrogans affected the uterus of dogs, by focusing on the inflammatory responses, and ECM expression in dogs uterine tissue infected by L. interrogans. In the present study, 27 dogs were divided into 3 groups, intrauterine infusion with L. interrogans, to make uterine infection, sterile EMJH, and normal saline as a control, respectively. The uteruses were removed by surgical operation in 10, 20, and 30 days, respectively. The methods of histopathological analysis, ELISA, Western blot and qPCR were used. The results showed that L. interrogans induced significantly inflammatory responses, which were characterized by inflammatory cellular infiltration and high expression levels of tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) in uterine tissue of these dogs. Furthermore, L. interrogans strongly down-regulated the expression of ECM (collagens (CL) IV, fibronectins (FN) and laminins (LN)) in mRNA and protein levels. These data indicated that strongly inflammatory responses, and abnormal regulation of ECM might contribute to the proliferation of dogs infected by L. interrogans.

Efficacy of cefepime, ertapenem and norfloxacin against leptospirosis and for the clearance of pathogens in a hamster model.

Animals and humans with severe leptospirosis may require empirical treatment. Although many antibiotics are active against multiple leptospira serovars in vitro, their efficacy in vivo is limited. We evaluated the efficacy of cefepime (daily dose: 2, 5, 10, and 20 mg/kg), ertapenem (daily dose: 2.5, 5, and 10 mg/kg) and norfloxacin (daily dose: 20, 40, and 80 mg/kg) for the treatment of leptospirosis and the ability to clear leptospira in target organs (liver, kidney, lung, heart, and spleen) in a lethal hamster model using Leptospira interrogans serovar Autumnalis. The histopathology of infected kidney, lung and liver was also evaluated using hematoxylin and eosin stain (H&E stain). All untreated animals, serving as a negative control, died with leptospira existing in the target organs between the 5th and 7th day after infection. All of the treated groups displayed improved survival compared to the untreated group and demonstrated a dose-dependent decrease in the presence of leptospira in the target organs. Cefepime showed survival benefit comparable to the standard treatment, doxycycline. We conclude that all of the antibiotics tested in vivo produce a statistically significant survival advantage, alleviate tissue injury and decrease the abundance of leptospira in target organs.

POPCORN functions in the auxin pathway to regulate embryonic body plan and meristem organization in Arabidopsis.

The shoot and root apical meristems (SAM and RAM) formed during embryogenesis are crucial for postembryonic plant development. We report the identification of POPCORN (PCN), a gene required for embryo development and meristem organization in Arabidopsis thaliana. Map-based cloning revealed that PCN encodes a WD-40 protein expressed both during embryo development and postembryonically in the SAM and RAM. The two pcn alleles identified in this study are temperature sensitive, showing defective embryo development when grown at 22°C that is rescued when grown at 29°C. In pcn mutants, meristem-specific expression of WUSCHEL (WUS), CLAVATA3, and WUSCHEL-RELATED HOMEOBOX5 is not maintained; SHOOTMERISTEMLESS, BODENLOS (BDL) and MONOPTEROS (MP) are misexpressed. Several findings link PCN to auxin signaling and meristem function: ectopic expression of DR5(rev):green fluorescent protein (GFP), pBDL:BDL-GFP, and pMP:MP-ß-glucuronidase in the meristem; altered polarity and expression of pPIN1:PIN1-GFP in the apical domain of the developing embryo; and resistance to auxin in the pcn mutants. The bdl mutation rescued embryo lethality of pcn, suggesting that improper auxin response is involved in pcn defects. Furthermore, WUS, PINFORMED1, PINOID, and TOPLESS are dosage sensitive in pcn, suggesting functional interaction. Together, our results suggest that PCN functions in the auxin pathway, integrating auxin signaling in the organization and maintenance of the SAM and RAM.