Genetic Structure of the Endangered Northeastern Bulrush (Scirpus ancistrochaetus) in Pennsylvania, USA, Using Information from RAPD and SNPs

The northeastern bulrush, Scirpus ancistrochaetus, is a federally endangered wetland plant species found primarily in Pennsylvania, USA. Data on the population genetic structureof this species are needed by conservation managers to prioritize conservation efforts. In this study, we used two genetic marker systems to examine diversity and structure of this species in populations throughout Pennsylvania. The first simple and inexpensive approach utilized RAPD primers; our second, more detailed approach relied on DNA sequencing of single nucleotide polymorphisms. We found genetic variation using both RAPDs and sequencing and found some overlap in information between the two methods, including clusters of related populations and the identification of a genetically unique population. Future studies will seek to examine variation across the full geographic range of the species.     

Atypical B cells are part of an alternative lineage of B cells that participates in responses to vaccination and infection in humans

1. Download : Download high-res image (238KB)
2. Download : Download full-size image

     

PfSPZ-CVac efficacy against malaria increases from 0% to 75% when administered in the absence of erythrocyte stage parasitemia: A randomized,placebo-controlled trial with controlled human malaria infection

PfSPZ-CVac combines ‘PfSPZ Challenge’, which consists of infectious Plasmodium falciparum sporozoites (PfSPZ), with concurrent antimalarial chemoprophylaxis. In a previously-published PfSPZ-CVac study, three doses of 5.12x10⁴ PfSPZ-CVac given 28 days apart had 100% vaccine efficacy (VE) against controlled human malaria infection (CHMI) 10 weeks after the last immunization, while the same dose given as three injections five days apart had 63% VE. Here, we conducted a dose escalation trial of similarly condensed schedules. Of the groups proceeding to CHMI, the first study group received three direct venous inoculations (DVIs) of a dose of 5.12x10⁴ PfSPZ-CVac seven days apart and the next full dose group received three DVIs of a higher dose of 1.024x10⁵ PfSPZ-CVac five days apart. CHMI (3.2x10³ PfSPZ Challenge) was performed by DVI 10 weeks after the last vaccination. In both CHMI groups, transient parasitemia occurred starting seven days after each vaccination. For the seven-day interval group, the second and third vaccinations were therefore administered coincident with parasitemia from the prior vaccination. Parasitemia was associated with systemic symptoms which were severe in 25% of subjects. VE in the seven-day group was 0% (7/7 infected) and in the higher-dose, five-day group was 75% (2/8 infected). Thus, the same dose of PfSPZ-CVac previously associated with 63% VE when given on a five-day schedule in the prior study had zero VE here when given on a seven-day schedule, while a double dose given on a five-day schedule here achieved 75% VE. The relative contributions of the five-day schedule and/or the higher dose to improved VE warrant further investigation. It is notable that administration of PfSPZ-CVac on a schedule where vaccine administration coincided with blood-stage parasitemia was associated with an absence of sterile protective immunity.Clinical trials registration: {"type":"clinical-trial","attrs":{"text":"NCT02773979","term_id":"NCT02773979"}}NCT02773979.     

Effects of a Ficoll-agarose system on early division and development of mesophyll protoplasts of winter oilseed rape (Brassica napus L.)

A method is described for regenerating callus from mesophyll protoplasts of a winter variety of Brassica napus. The method combines the use of Ficoll in an initial liquid medium, enhancing early protoplast division and cell colony formation, with a transfer to an agarose system after 10 days culture to give rapid microcalli formation. Further transfers resulted in callus regeneration and the initiation of organogenesis.     

Avian gonadotropin-releasing hormones I and II in brain and other tissues in turkey hens

1. Radioimmunoassays were developed for measuring avian gonadotropin-releasing hormones I and II (cGnRH I and II) in tissue extracts during the reproductive cycle. 2. Hypothalamic concentrations of cGnRH I and II were qualitatively similar being lowest in non-photostimulated hens, greater in laying hens and greatest in incubating hens. 3. cGnRH II concentrations were similar in paraolfactory lobe and hypothalamic fragments while lesser amounts were found in cerebrum, cerebellum, duodenum, shell gland, and pineal. 4. These results suggest that cGnRH II has unknown functions in turkeys quite distinct from traditional functions associated with GnRHs.     

A slot-blot hybridisation method for screening somatic hybrids

A slot-blot method is described that provides rapid and reliable identification of somatic hybrids. Biotin-labelled probes of defined length were prepared from genomic DNA, and calibrated in conjunction with target DNA to allow for differing amounts of biotin incorporation and hybridisation efficiency. The presence of probe DNA was visualised by chemiluminescence detection. Probes of 1 to 5 kbp in length gave optimal discrimination among target DNAs from different potato species. The advantages of this method over existing ones are described.     

Genotype-specific regeneration from a number of Rubus cultivars

Eight Rubus genotypes were examined for their ability to regenerate on 55 media differing in their plant growth substance content. Regeneration was obtained from all cultivars examined, though efficiency varied greatly depending on genotype. A minimum threshold level of thidiazuron was found to be required for regeneration from leaf discs, and the optimum level for efficient regeneration varied among cultivars. Zeatin was not found to be as effective. Thidiazuron supplemented with a range of individual auxins was investigated, and it was found that NAA had a complementary effect, applicable across a wide range of cultivars at relatively low levels. Using five random primers, 28 polymorphic PCR amplification products (RAPD markers) were stably generated and used to discriminate all eight genotypes investigated. A similarity matrix and dendrogram was generated from the markers and this was related to their regenerative ability. This revised version was published online in June 2006 with corrections to the Cover Date.