Plasticity and variability in the patterns of phytolith formation in Asteraceae species along a large rainfall gradient in Israel

Silicification and phytolith formation in Poaceae species growing in arid and semi-arid regions are commonly thought to be positively correlated with silica and water availabilities and with transpiration. To expand our understanding of this phenomenon, we chose to study species of the Asteraceae, the largest dicotyledonous family. We measured phytolith concentrations in eight Asteraceae species (three non-spiny and five spiny) and one Poaceae species (Avena sterilis), as reference, along a large climatic gradient of 80–900 mm mean annual rainfall in Israel.     

Maresin 1 attenuates pro-inflammatory activation induced by β-amyloid and stimulates its uptake

Alzheimer's disease (AD) is the most common dementia, characterized by pathological accumulation of β-amyloid (Aβ) and hyperphosphorylation of tau protein, together with a damaging chronic inflammation. The lack of effective treatments urgently warrants new therapeutic strategies. Resolution of inflammation, associated with beneficial and regenerative activities, is mediated by specialized pro-resolving lipid mediators (SPMs) including maresin 1 (MaR1). Decreased levels of MaR1 have been observed in AD brains. However, the pro-resolving role of MaR1 in AD has not been fully investigated. In the present study, human monocyte-derived microglia (MdM) and a differentiated human monocyte cell line (THP-1 cells) exposed to Aβ were used as models of AD neuroinflammation. We have studied the potential of MaR1 to inhibit pro-inflammatory activation of Aβ and assessed its ability to stimulate phagocytosis of Aβ₄₂. MaR1 inhibited the Aβ₄₂-induced increase in cytokine secretion and stimulated the uptake of Aβ₄₂ in both MdM and differentiated THP-1 cells. MaR1 was also found to decrease chemokine secretion and reduce the associated increase in the activation marker CD40. Activation of kinases involved in transduction of inflammation was not affected by MaR1, but the activity of nuclear factor (NF)-κB was decreased. Our data show that MaR1 exerts effects that indicate a pro-resolving role in the context of AD and thus presents itself as a potential therapeutic target for AD.     

Proffered Papers 16.00–16.30 Monday 15 September 2003

Human papillomaviruses and Chlamydia trachomatis are two of the most commonly found sexually transmitted infections in cervical Pap smears. They are often asymptomatic and if left untreated can progress to cause serious complications such as pre-cancerous lesions and tubal factor infertility, respectively. The aim of this study was to develop a rapid multiplex PCR for the simultaneous detection of HPV and C. trachomatis in ThinPrep^® liquid cytology samples. Two multiplexes were optimized. (A) For the detection of C. trachomatis using primers for the cryptic plasmid and for a chromosomal gene ( Hsp60 ); (B) for the simultaneous detection of HPV and C. trachomatis using consensus primers for HPV and plasmid primers for C. trachomatis . Both multiplexes included a set of primers for a human housekeeping gene- β -globin. DNA from 34 ThinPrep^® cervical samples was extracted using the QiAmp DNA Mini Kit (Qiagen Ltd, UK). All 34 samples were previously confirmed positive for C. trachomatis using another nucleic-acid based test. Using multiplex A.for the detection of C. trachomatis , 33 of 34 samples were positive for C. trachomatis by either the plasmid or chromosomal gene primer set. All samples were positive for β -globin. Ten of the 34 C. trachomatis positive samples were known positives for HPV. Using the combined HPV and C. trachomatis multiplex 10 of 10 were positive for both HPV and C. trachomatis . These simple multiplexes are cost-effective, rapid and have potential for rapid screening of cervical ThinPrep samples simultaneously for both HPV and C. trachomatis .     

Down-regulation of natural killer cell activity in MoLV leukemogenesis: evidence for tumor-cell-mediated suppression

The role of natural killer (NK) cells in retrovirus-induced leukemogenesis was studied. These cells which do not require prior sensitization are considered as a part of the body's defense system against tumor development and spread. Neonate BALB/c mice infected with Moloney murine leukemia virus (MoLV) develop leukemia within 3-6 months. The MoLV-infected mice showed a progressive loss of endogenous and augmented NK activity, correlated with the development of the leukemic state. Mixing of spleen cells from tumor-bearing mice with NK-augmented splenocytes resulted in suppression of NK activity. In addition, mixing of T cell lines isolated from MoLV-induced tumors with augmented splenocytes also resulted in the down-regulation of NK cell activity. The present study demonstrates that tumor cells from leukemic organs and leukemic T cell lines can actively suppress NK cell function. It is postulated that after MoLV infection the progression of virus-transformed T cells to a fully developed tumor depends on the ability of these cells to down-regulate NK cell activity and thus escape immune surveillance.     

Silicification patterns in wheat leaves related to ontogeny and soil silicon availability under field conditions

Plant and Soil - Silicon (Si) accumulation is an important strategy for plant defense against biotic and abiotic stress. Solid amorphous silica (ASi) deposits have been found to protect plants...     

Pathogenicity of clinical Salmonella enterica serovar Typhimurium isolates from Thailand in a mouse colitis model

Salmonella enterica serovar Typhimurium (S. Typhimurium [STM]) is a leading cause of nontyphoidal salmonellosis (NTS) worldwide. The pathogenesis of NTS has been studied extensively using a streptomycin-pretreated mouse colitis model with the limited numbers of laboratory STM strains. However, the pathogenicity of the clinically isolated STM (STMC) strains endemic in Thailand in mice has not been explored. The aim of this study was to compare the pathogenicity of STMC strains collected from Northern Thailand with the laboratory STM (IR715) in mice. Five STMC isolates were obtained from the stool cultures of patients with acute NTS admitted to Maharaj Nakorn Chiang Mai Hospital in 2016 and 2017. Detection of virulence genes and sequence type (ST) of the strains was performed. Female C57BL/6 mice were pretreated with streptomycin sulfate 1 day prior to oral infection with STM. On Day 4 postinfection, mice were euthanized, and tissues were collected to analyze the bacterial numbers, tissue inflammation, and cecal histopathological score. We found that all five STMC strains are ST34 and conferred the same or reduced pathogenicity compared with that of IR715 in mice. A strain-specific effect of ST34 on mouse gut colonization was also observed. Thailand STM ST34 exhibited a significant attenuated systemic infection in mice possibly due to the lack of spvABC-containing virulence plasmid.