Ticks (Ixodidae) on humans in South America

Twenty eight species of Ixodidae have been found on man in South America (21 Amblyomma, 1 Boophilus, 2 Dermacentor, 2 Haemaphysalis, 1 Ixodes and 1 Rhipicephalus species). Most of them are rarely found on man. However, three species frequently parasitize humans in restricted areas of Argentina (A. neumanni reported from 46 localities), Uruguay (A. triste from 21 sites) and Argentina–Brazil (A. parvum from 27 localities). The most widespread ticks are A. cajennense (134 localities in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela), A. ovale (37 localities in Argentina, Brazil, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela) and A. oblongoguttatum (28 sites in Brazil, Colombia, French Guiana, Guyana, Suriname and Venezuela). Amblyomma aureolatum (18 localities in Argentina, Brazil, French Guiana and Paraguay), A. cajennense, and A. triste are vectors of rickettsioses to man in South America. A better understanding of the respective roles of these and other tick species in transmitting pathogens to humans will require further local investigations. Amblyomma ticks should be the main subjects of these studies followed by species of Boophilus, Dermacentor, Haemaphysalis and Rhipicephalus species. In contrast with North America, Europe and Asia, ticks of the genus Ixodes do not appear to be major players in transmitting diseases to human. Indeed, there is only one record of an Ixodes collected while feeding on man for all South America.     

Early responses to Nod factors and mycorrhizal colonization in a non-nodulating Phaseolus vulgaris mutant

Legumes can acquire nitrogen through a symbiotic interaction with rhizobial bacteria. The initiation of this process is determined by a molecular dialogue between the two partners. Legume roots exude flavonoids that induce the expression of the bacterial nodulation genes, which encode proteins involved in the synthesis and secretion of signals called Nod factors (NFs). NFs signal back to the plant root and trigger several responses, leading to bacterial invasion and nodule formation. Here, we describe the molecular and cellular characterization of a Phaseolus vulgaris non-nodulating mutant (NN-mutant). Root hair cells of the NN-mutant plant respond with swelling and branching when inoculated with Rhizobium etli, albeit without curling induction. Furthermore, neither initiation of cell division in the outer cortex, nor entrapment of bacteria nor infection thread formation was observed. Both the bean wild-type and the NN-mutant responded with elevated intracellular calcium changes in the root hairs. Although the NN-mutant is deficient in early nodulin gene expression when inoculated with R. etli, it can be effectively colonized by arbuscular mycorrhizal fungi (Glomus intraradices). Our data indicate that the P. vulgaris NN-mutant is not blocked at the NFs early perception stage, but at later downstream stages between Ca²⁺ signaling and early nodulin induction. This supports the idea that both microsymbionts are perceived and trigger different downstream pathways in the host plant.     

Long-lived alphaMUPA transgenic mice exhibit pronounced circadian rhythms

Robust biological rhythms have been shown to affect life span. Biological clocks can be entrained by two feeding regimens, restricted feeding (RF) and caloric restriction (CR). RF restricts the time of food availability, whereas CR restricts the amount of calories with temporal food consumption. CR is known to retard aging and extend life span of animals via yet-unknown pathways. We hypothesize that resetting the biological clock could be one possible mechanism by which CR extends life span. Because it is experimentally difficult to uncouple calorie reduction from temporal food consumption, we took advantage of the murine urokinase-like plasminogen activator (alphaMUPA) transgenic mice overexpressing a serine protease implicated in brain development and plasticity; they exhibit spontaneously reduced eating and increased life span. Quantitative real-time PCR analysis revealed that alphaMUPA mice exhibit robust expression of the clock genes mPer1, mPer2, mClock, and mCry1 but not mBmal1 in the liver. We also found changes in the circadian amplitude and/or phase of clock-controlled output systems, such as feeding behavior, body temperature, and enteric cryptdin expression. A change in the light-dark regimen led to modified clock gene expression and abrogated circadian patterns of food intake in wild-type (WT) and alphaMUPA mice. Consequently, food consumption of WT mice increased, whereas that of alphaMUPA mice remained the same, indicating that reduced food intake occurs upstream and independently of the biological clock. Thus we surmise that CR could lead to pronounced and synchronized biological rhythms. Because the biological clock controls mitochondrial, hormonal, and physiological parameters, system synchronicity could lead to extended life span.     

Haptoglobin polymorphism among fourteen populations of India

Haptoglobin (HP) is a serum protein that has the capability of binding the extracorpuscular haemoglobin released during haemolysis. It plays an important role in protection of haemolytic disease by reducing the oxidative and peroxidative potential at free haemoglobin. The present study was aimed to determine the prevalence of HP polymorphism among different Indian populations, anthropologically belonging to diverse ethnicity. The polymorphism was screened among 642 unrelated individuals belonging to 14 population groups of India including both tribal and non-tribal caste groups from different geographical regions of India with distinct linguistic affiliations. An attempt is also made to understand the distribution of HP polymorphism among the studied populations. The result reveals the HP gene to be polymorphic in all the studied populations. Except the two tribal populations (Thotis of Andhra Pradesh and Patelias of Rajasthan) and one caste population (Rajput of Himachal Pradesh), all the studied populations are found to obey the Hardy-Weinberg equilibrium. The significance of the present study is elucidated with the prevalence of high mutant HP*2 allele frequency in India. Selection could be one of the most plausible explanations for this high HP frequency because of its uniformly high occurrence among all the studied populations.     

The Arabidopsis‐related halophyte Thellungiella halophila: boron tolerance via boron complexation with metabolites?

Tolerance to boron (B) is still not completely understood. We tested here the hypothesis that Thellungiella halophila, an Arabidopsis thaliana-related 'extremophile' plant, with abundance of B in its natural environment, is tolerant to B, and examined the potential mechanisms of this tolerance. With 1-10 mm B applied ([B](ext)) to Thellungiella and Arabidopsis grown in hydroponics, the steady-state accumulated B concentration ([B](int)) in the root was below [B](ext), and was similar in both, suggesting both extrude B actively. Whether grown in soil or hydroponically, the shoot [B](int) was higher in Arabidopsis than in Thellungiella, suggesting more effective net B exclusion by Thellungiella root. Arabidopsis exhibited toxicity symptoms including reduced shoot fresh weight (FW), but Thellungiella was not affected, even at similar levels of shoot-accumulated [B](int) (about 10 to 40 mm B in 'shoot water'), suggesting additional B tolerance mechanism in Thellungiella shoot. At [B](ext) = 5 mm, the summed shoot concentration of the potentially B-binding polyhydroxyl metabolites (malic acid, fructose, glucose, sucrose and citric acid) in Arabidopsis was below [B](int) , but in Thellungiella it was over twofold higher than [B](int) , and therefore likely to allow appreciable 1:2 boron-metabolite complexation in the shoot. This, we suggest, is an important component of Thellungiella B tolerance mechanism.     

Haploinsufficiency of a spliceosomal GTPase encoded by EFTUD2 causes mandibulofacial dysostosis with microcephaly

Mandibulofacial dysostosis with microcephaly (MFDM) is a rare sporadic syndrome comprising craniofacial malformations, microcephaly, developmental delay, and a recognizable dysmorphic appearance. Major sequelae, including choanal atresia, sensorineural hearing loss, and cleft palate, each occur in a significant proportion of affected individuals. We present detailed clinical findings in 12 unrelated individuals with MFDM; these 12 individuals compose the largest reported cohort to date. To define the etiology of MFDM, we employed whole-exome sequencing of four unrelated affected individuals and identified heterozygous mutations or deletions of EFTUD2 in all four. Validation studies of eight additional individuals with MFDM demonstrated causative EFTUD2 mutations in all affected individuals tested. A range of EFTUD2-mutation types, including null alleles and frameshifts, is seen in MFDM, consistent with haploinsufficiency; segregation is de novo in all cases assessed to date. U5-116kD, the protein encoded by EFTUD2, is a highly conserved spliceosomal GTPase with a central regulatory role in catalytic splicing and post-splicing-complex disassembly. MFDM is the first multiple-malformation syndrome attributed to a defect of the major spliceosome. Our findings significantly extend the range of reported spliceosomal phenotypes in humans and pave the way for further investigation in related conditions such as Treacher Collins syndrome.     

One-step synthesis of biodegradable curcumin-derived hydrogels as potential soft tissue fillers after breast cancer surgery

A one-step synthesis of a curcumin-derived hydrogel (curcumin content of 25-75 mol %) is reported. Curcumin is incorporated into the hydrogel backbone and cross-linked through biodegradable carbonate linkages. Curcumin as a part of the polymer backbone is protected from oxidation and degradation, while hydrogel hydrolysis results in the release of active curcumin. Nontoxic poly(ethylene glycol) and desaminotyrosyl-tyrosine ethyl ester are used to tune the hydrophilic/hydrophobic hydrogel properties. In this way, hydrogels with a wide range of physical properties including water-uptake (100-550%) and compression moduli (7-100 kPa) were obtained. Curcumin release is swelling-controlled and could be extended to 80 days. In vitro, curcumin-derived hydrogels showed selective cytotoxicity against MDA-MB-231 (IC(50) 9 μM) breast cancer cells but no cytotoxicity to noncancerous quiescent human dermal fibroblasts even at high curcumin concentrations (160 μM). One possible application of these curcumin-derived hydrogels is as soft tissue filler after surgical removal of cancerous tissue.