Surface charge and dosage dependent potential developmental toxicity and biodistribution of iron oxide nanoparticles in pregnant CD-1 mice.

Iron oxide nanoparticles have attracted much attention because of their potential applications, such as drug delivery, biomedical imaging, and photocatalysis. Due to their small size and the potential to cross the placental barrier, the risk to pregnant women and the developing fetus from exposure to nanoparticles is of great concern. The developmental toxicity and biodistribution of a single dose versus multiple doses of iron oxide nanoparticles with positive or negative surface charges were investigated in vivo. Multiple doses of positively-charged nanoparticles given over several days resulted in significantly increased fetal deaths and accumulation of iron in the fetal liver and placenta. These results indicate both positively and negatively charged iron oxide nanoparticles have the ability to cross the placenta and accumulate in the fetus, though greater bioaccumulation and toxicity was observed with a positively-charged surface coating.

A recombinant inhibitory isoform of vascular endothelial growth factor164/165 aggravates ischemic brain damage in a mouse model of focal cerebral ischemia.

Vascular endothelial growth factors (VEGF) are a Janus-faced family of growth factors exerting both neuroprotective and maladaptive effects on the blood-brain barrier. For example, VEGFs are beneficial in promoting postischemic brain angiogenesis, but the newly formed vessels are leaky. We investigated the role of the naturally occurring murine inhibitory VEGF isoform VEGF165b in a mouse model of focal cerebral ischemia by middle cerebral artery occlusion and reperfusion (I/R) in male C57BL/6 mice. We investigated the roles of VEGF164/165 and VEGF165b in both brain and nonbrain endothelial barrier, angiogenesis, and neutrophil migration using oxygen glucose deprivation and reoxygenation as in vitro model. We investigated the role of VEGF165b in brain edema, neutrophil infiltration, ischemic brain damage, and neuronal death in vivo using an adenovirus encoding a recombinant VEGF164b isoform. Neither VEGF164/165 nor VEGF165b significantly altered brain endothelial barrier or angiogenesis in vitro. However, treatment of brain endothelial cells with VEGF165b increased neutrophil migration in vitro and exacerbated stroke injury by aggravating neutrophil infiltration and neurodegeneration in vivo. Our results indicate that alterations in the delicate balance in the relative levels of pro- and antiangiogenic VEGF isoforms can result in either adaptive or detrimental effects, depending on the VEGF isoform levels and on the duration and extent of injury.

Engineered vaginal lactobacillus strain for mucosal delivery of the human immunodeficiency virus inhibitor cyanovirin-N.

Women are at significant risk of human immunodeficiency virus (HIV) infection, with the cervicovaginal mucosa serving as a major portal for virus entry. Female-initiated preventatives, including topical microbicides, are urgently needed to help curtail the HIV/AIDS pandemic. Here we report on the development of a novel, live microbicide that employs a natural vaginal strain of Lactobacillus jensenii engineered to deliver the potent HIV inhibitor cyanovirin-N (CV-N). To facilitate efficient expression of CV-N by this bacterium, the L. jensenii 1153 genome was sequenced, allowing identification of native regulatory elements and sites for the chromosomal integration of heterologous genes. A CV-N expression cassette was optimized and shown to produce high levels of structurally intact CV-N when expressed in L. jensenii. Lactobacillus-derived CV-N was capable of inhibiting CCR5-tropic HIV(BaL) infectivity in vitro with a 50% inhibitory concentration of 0.3 nM. The CV-N expression cassette was stably integrated as a single copy into the bacterial chromosome and resolved from extraneous plasmid DNA without adversely affecting the bacterial phenotype. This bacterial strain was capable of colonizing the vagina and producing full-length CV-N when administered intravaginally to mice during estrus phase. The CV-N-producing Lactobacillus was genetically stable when propagated in vitro and in vivo. This work represents a major step towards the development of an inexpensive yet durable protein-based microbicide to block the heterosexual transmission of HIV in women.

Genomic analysis of Oenococcus oeni PSU-1 and its relevance to winemaking.

Oenococcus oeni is an acidophilic member of the Leuconostoc branch of lactic acid bacteria indigenous to wine and similar environments. O. oeni is commonly responsible for the malolactic fermentation in wine and due to its positive contribution is frequently used as a starter culture to promote malolactic fermentation. In collaboration with the Lactic Acid Bacteria Genome Consortium the genome sequence of O. oeni PSU-1 has been determined. The complete genome is 1,780,517 nt with a GC content of 38%. 1701 ORFs could be predicted from the sequence of which 75% were functionally classified. Consistent with its classification as an obligately heterofermentative lactic acid bacterium the PSU-1 genome encodes all the enzymes for the phosphoketolase pathway. Moreover, genes related to flavor modification in wine, such as malolactic fermentation capacity and citrate utilization were readily identified. The completion of the O. oeni genome marks a significant new phase for wine-related research on lactic acid bacteria in which the physiology, genetic diversity and performance of O. oeni starter cultures can be more rigorously examined.