Properties of group I allergens from grass pollen and their relation to cathepsin B, a member of the C1 family of cysteine proteinases.

Expansins are a family of proteins that catalyze pH-dependent long-term extension of isolated plant cell walls. They are divided into two groups, alpha and beta, the latter consisting of the grass group I pollen allergens and their vegetative homologs. Expansins are suggested to mediate plant cell growth by interfering with either structural proteins or the polysaccharide network in the cell wall. Our group reported papain-like properties of beta-expansin of Timothy grass (Phleum pratense) pollen, Phl p 1, and suggested that cleavage of cell wall structural proteins may be the underlying mechanism of expansin-mediated wall extension. Here, we report additional data showing that beta-expansins resemble ancient and modern cathepsin B, which is a member of the papain (C1) family of cysteine proteinases. Using the Pichia pastoris expression system, we show that cleavage of inhibitory prosequences from the recombinant allergen is facilitated by its N-glycosylation and that the truncated, activated allergen shows proteolytic activity, resulting in very low stability of the protein. We also show that deglycosylated, full-length allergen is not activated efficiently and therefore is relatively stable. Motif and homology search tools detected significant similarity between beta-expansins and cathepsins of modern animals as well as the archezoa Giardia lamblia, confirming the presence of inhibitory prosequences, active site and other functional amino-acid residues, as well as a conserved location of these features within these molecules. Lastly, we demonstrate by site-directed mutagenesis that the conserved His104 residue is involved in the catalytic activity of beta-expansins. These results indicate a common origin of cathepsin B and beta-expansins, especially if taken together with their previously known biochemical properties.     

Using HIV Surveillance Registry Data to Re-Link Persons to Care: The RSVP Project in San Francisco

Background

Persons with unsuppressed HIV viral load (VL) who disengage from care may experience poor clinical outcomes and potentially transmit HIV. We assessed the feasibility and yield of using the San Francisco Department of Public Health (SFDPH) enhanced HIV surveillance system (eHARS) to identify and re-engage such persons in care.

Methods

Using SFDPH eHARS data as of 4/20/2012 (index date), we selected HIV-infected adults who were alive, had no reported VL or CD4 cell count results in the past nine months (proxy for “out-of-care”) and a VL >200 copies/mL drawn nine to 15 months earlier. We prioritized cases residing locally for investigation, and used information from eHARS and medical and public health databases to contact them for interview and referral to the SFDPH linkage services (LINCS). Twelve months later, we matched-back to eHARS data to assess how HIV laboratory reporting delays affected original eligibility, and if persons had any HIV laboratory results performed and reported within 12 months after index date (‘new labs’).

Results

Among 434 eligible persons, 282 were prioritized for investigation, of whom 75 (27%) were interviewed, 79 (28%) could not be located, and 48 (17%) were located out of the area. Among the interviewed, 54 (72%) persons accepted referral to LINCS. Upon match-back to eHARS data, 324 (75%) in total were confirmed as eligible, including 221 (78%) of the investigated; most had new labs.

Conclusions

Among the investigated persons presumed out-of-care, we interviewed and offered LINCS referral to about one-quarter, demonstrating the feasibility but limited yield of our project. Matching to updated surveillance data revealed that a substantial minority did not disengage from care and that most re-engaged in HIV care. Verifying persons’ HIV care status with medical providers and improving timeliness of transfer and cross-jurisdictional sharing of HIV laboratory data may aid future efforts.     

A temperate bacteriophage specific for strains ofAeromonas salmonicida possessing A-layer,a cell surface virulence factor

A temperate bacteriophage designated TP446 was isolated from culture supernatants ofAeromonas salmonicida strain A446. Phage TP446 adsorbed to all of the typical and atypical strains ofA. salmonicida tested that possessed A-layer, the surface protein array that represents the primary virulence factor of this fish pathogen. In contrast, TP446 failed to adsorb to mutants lacking A-layer. These results indicate that the A-layer is a component of the receptor for phage TP446.     

Characterization of water and wildlife strains as a subgroup of Campylobacter jejuni using DNA microarrays

Campylobacter jejuni is the leading cause of human bacterial gastroenteritis worldwide, but source attribution of the organism is difficult. Previously, DNA microarrays were used to investigate isolate source, which suggested a non‐livestock source of infection. In this study we analysed the genome content of 162 clinical, livestock and water and wildlife (WW) associated isolates combined with the previous study. Isolates were grouped by genotypes into nine clusters (C1 to C9). Multilocus sequence typing (MLST) data demonstrated that livestock associated clonal complexes dominated clusters C1–C6. The majority of WW isolates were present in the C9 cluster. Analysis of previously reported genomic variable regions demonstrated that these regions were linked to specific clusters. Two novel variable regions were identified. A six gene multiplex PCR (mPCR) assay, designed to effectively differentiated strains into clusters, was validated with 30 isolates. A further five WW isolates were tested by mPCR and were assigned to the C7‐C9 group of clusters. The predictive mPCR test could be used to indicate if a clinical case has come from domesticated or WW sources. Our findings provide further evidence that WW C. jejuni subtypes show niche adaptation and may be important in causing human infection.     

"This Job Is Harder Than It Looks": Rural Oaxacan Women Explain Why They Became Teachers

During the past six decades, rural women throughout the southeastern state of Oaxaca, Mexico, have comprised a significant percentage (currently the majority) of primary teachers. This article demonstrates that this phenomenon is a result of intertwining socioeconomic factors. It examines why expansion of the education system and economic opportunities may contribute to declining enrollment in teacher training programs even though the career remains a viable, and even desirable, choice for certain rural women.     

Gait retraining to reduce the knee adduction moment through real-time visual feedback of dynamic knee alignment

Varus knee alignment is a risk factor for medial knee osteoarthritis and is associated with high knee adduction moments. Therefore, reducing the knee adduction moment in varus-aligned individuals with otherwise healthy knees may reduce their risk for developing osteoarthritis. A gait modification that improves dynamic knee alignment may reduce the adduction moment, and systematic training may lead to more natural-feeling and less effortful execution of this pattern. To test these hypotheses, eight healthy, varus-aligned individuals underwent a gait modification protocol. Real-time feedback of dynamic knee alignment was provided over eight training sessions, using a fading paradigm. Natural and modified gait were assessed post-training and after 1 month, and compared to pre-training natural gait. The knee adduction moment, as well as hip adduction, hip internal rotation and knee adduction angles were evaluated. At each training session, subjects rated how effortful and natural-feeling the modified pattern was to execute. Post-training, the modified pattern demonstrated an 8° increase in hip internal rotation and 3° increase in hip adduction. Knee adduction decreased 2°, and the knee adduction moment decreased 19%. Natural gait did not differ between the three visits, nor did the modified gait pattern between the post-training and 1 month visits. The modified pattern felt more natural and required less effort after training. Based on these results, gait retraining to improve dynamic knee alignment resulted in significant reductions in the knee adduction moment, primarily through hip internal rotation. Further, systematic training led to more natural-feeling and less effortful execution of the gait pattern.     

Glycosaminoglycan-dependent restriction of FGF diffusion is necessary for lacrimal gland development

Glycosaminoglycans (GAGs) play a central role in embryonic development by regulating the movement and signaling of morphogens. We have previously demonstrated that GAGs are the co-receptors for Fgf10 signaling in the lacrimal gland epithelium, but their function in the Fgf10-producing periocular mesenchyme is still poorly understood. In this study, we have generated a mesenchymal ablation of UDP-glucose dehydrogenase (Ugdh), an essential biosynthetic enzyme for GAGs. Although Fgf10 RNA is expressed normally in the periocular mesenchyme, Ugdh mutation leads to excessive dispersion of Fgf10 protein, which fails to elicit an FGF signaling response or budding morphogenesis in the presumptive lacrimal gland epithelium. This is supported by genetic rescue experiments in which the Ugdh lacrimal gland defect is ameliorated by constitutive Ras activation in the epithelium but not in the mesenchyme. We further show that lacrimal gland development requires the mesenchymal expression of the heparan sulfate N-sulfation genes Ndst1 and Ndst2 but not the 6-O and 2-O-sulfation genes Hs6st1, Hs6st2 and Hs2st. Taken together, these results demonstrate that mesenchymal GAG controls lacrimal gland induction by restricting the diffusion of Fgf10.