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We tested serum samples collected in 1997 and 1998 from a cohort of 204 injection drug users (IDUs) recruited from Central and East Harlem, New York City, New York, for antibodies reactive with seven rickettsial or Bartonella spp. antigens. Rodent-associated Bartonella elizabethae and Rickettsia akari were the primary etiologic agents of interest. The testing panel also included Bartonella henselae, Bartonella quintana, Rickettsia prowazekii, Rickettsia rickettsii, and Rickettsia typhi. The highest prevalence of seroreactive serum samples (46%) was found with B. elizabethae antigens; 10% of the samples reacted with B. henselae antigens, while 2% reacted with B. quintana antigens. Reactivity to the latter two antigens was likely due to cross-reactivity with B. elizabethae antigens in most instances. Among the spotted fever group rickettsiae, 18 (9%) samples reacted with R. akari, including 10 samples (5%) that also reacted with R. rickettsii. Cross-adsorption studies demonstrated that most of the spotted fever group rickettsiae antibodies were due to R. akari infections. Among the typhus group rickettsiae, 5 samples reacted weakly to R. prowazekii antigens, and no samples reacted with R. typhi antigens. These findings suggest that Harlem IDUs are commonly exposed to two rodent-associated zoonotic agents. Further study of IDU populations may help elucidate transmission cycles of these agents in inner cities where higher levels of transmission occur.

Wolbachia are widespread maternally-inherited bacteria suggested to play a role in arthropod host speciation through induction of cytoplasmic incompatibility, but this hypothesis remains controversial. Most studies addressing Wolbachia-induced incompatibilities concern closely-related populations, which are intrinsically compatible. Here, we used three populations of two genetically differentiated colour forms of the haplodiploid spider mite Tetranychus urticae to dissect the interaction between Wolbachia-induced and host-associated incompatibilities, and to assess their relative contribution to post-mating isolation. We found that these two sources of incompatibility act through different mechanisms in an additive fashion. Host-associated incompatibility contributes 1.5 times more than Wolbachia-induced incompatibility in reducing hybrid production, the former through an overproduction of haploid sons at the expense of diploid daugters (ca. 75% decrease) and the latter by increasing the embryonic mortality of daughters (by ca. 49%). Furthermore, regardless of cross direction, we observed nearcomplete F1 hybrid sterility and complete F2 hybrid breakdown between populations of the two forms, but that Wolbachia did not contribute to this outcome. This study identifies the mechanistic independence and additive nature of host-intrinsic and Wolbachia-induced sources of isolation. It suggests that Wolbachia could drive reproductive isolation in this system, thereby potentially affecting host differentiation and distribution in the field.

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Magnetic nanoparticles (NP), such as magnetite, have been the subject of research for application in the biomedical field, especially in Magnetic Hyperthermia Therapy (MHT), a promising technique for cancer therapy. NP are often coated with different compounds such as natural or synthetic polymers to protect them from oxidation and enhance their colloidal electrostatic stability while maintaining their thermal efficiency. In this work, the synthesis and characterization of magnetite nanoparticles coated with fucoidan, a biopolymer with recognized biocompatibility and antitumoral activity, is reported. The potential application of NP in MHT was evaluated through the assessment of Specific Loss Power (SLP) under an electromagnetic field amplitude of 14.7 kA m−1 and at 276 kHz. For fucoidan-coated NP, it was obtained SLP values of 100 and 156 W/g, corresponding to an Intrinsic Loss Power (ILP) of 1.7 and 2.6 nHm2kg−1, respectively. These values are, in general, higher than the ones reported in the literature for non-coated magnetite NP or coated with other polymers. Furthermore, in vitro assays showed that fucoidan and fucoidan-coated NP are biocompatible. The particle size (between ca. 6 to 12 nm), heating efficiency, and biocompatibility of fucoidan-coated magnetite NP meet the required criteria for MHT application.

Magnetite nanoparticles were synthesized by the co-precipitation method with and without the assistance of an additive, namely, gelatin, agar-agar or pectin, using eco-friendly conditions and materials embodying a green synthesis process. X-ray diffraction and transmission electron microscopy were used to analyze the structure and morphology of the nanoparticles. Magnetic properties were investigated by SQUID magnetometry and 57Fe Mössbauer spectroscopy. The results show that the presence of the additives implies a higher reproducibility of the morphological magnetic nanoparticle characteristics compared with synthesis without any additive, with small differences associated with different additives. To assess their potential for magnetic hyperthermia, water-based suspensions of these nanoparticles were prepared with and without citric acid. The stable solutions obtained were studied for their structural, magnetic and heating efficiency properties. The results indicate that the best additive for the stabilization of a water-based emulsion and better heating efficiency is pectin or a combination of pectin and agar-agar, attaining an intrinsic loss power of 3.6 nWg-1.

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Laboratory studies are often criticized for not being representative of processes occurring in natural populations. This can be partially mitigated by using lab populations that capture large amounts of variation. Additionally, many studies addressing adaptation of organisms to their environment are done with laboratory populations, using quantitative genetics or experimental evolution methodologies. Such studies rely on populations that are either highly outbred or inbred. However, the methodology underlying the generation of such biological resources are usually not explicitly documented.Given their small size, short generation time, amenability to laboratory experimentation and knowledge of their ecological interactions, haplodiploid spider mites are becoming a widely used model organism. Here, we describe the creation of outbred populations of two species of spider mites, Tetranychus urticae and T. evansi, obtained by performing controlled crosses between individuals from field-collected populations. Subsequently, from the outbred population of T. evansi, we derived inbred lines, by performing several generations of sibmating. These can be used to measure broad-sense heritability as well as correlations among traits. Finally, we outline an experimental evolution protocol that can be widely used in other systems. Sharing these biological resources with other laboratories and combining them with the available powerful genetic tools for T. urticae (and other species) will allow consistent and comparable studies that greatly contribute to our understanding of ecological and evolutionary processes. DPG and SM designed the study with help from LRR and FZ. DPG and LRR collected the spider mite populations. The creation of the outbred and inbred populations was performed by DPG, MAC, MCM, JTP and CE. FZ and IF developed the formula to calculate the coefficient of inbreeding and the effective number of generations of selection. The manuscript was written by DPG and SM with considerable contributions from all authors. References Agashe, D. (2009). The stabilizing effect of intraspecific genetic variation on population dynamics in novel and ancestral habitats.