Biology subjects

Dagan, R.

Publications and source records attributed to Dagan, R..

4 recordsLinked to original sources

bioRxiv2023

The potential of young vegetative quinoa (Chenopodium quinoa) as a new sustainable protein-rich winter leafy crop under Mediterranean climate

The demand for protein products has significantly risen in the last few years. In western countries, animals are the primary source of protein; however, plants could take a share of this market due to lower production costs, among other advantages. Quinoa (Chenopodium quinoa Willd.) is a well- known but under-utilized protein-rich crop, commonly cultivated for grain production. These plants were recently evaluated for their use as a non-traditional, green leafy crop. Here we assessed the potential of young vegetative quinoa as a new sustainable winter leafy crop in Israel--serving as a model for Mediterranean semi-arid regions, by evaluating yield, protein content and quality. Five quinoa accessions were sown on three winter sowing dates over two consecutive years. Plants were harvested when they reached 10-13% dry matter (DM). DM yield ranged between 574 and 1,982 kg ha-1 and was generally higher in the second year. Protein content ranged from 14.4-34% and was generally higher in the first year. Protein yield ranged from 111-471 kg ha-1 and was greatest on the December sowing date. DM and protein yields were positively correlated with plant density. Protein content was negatively correlated with plant density and DM yield. Our findings show that 200 g DM of young vegetative quinoa can meet the protein and most essential amino acid requirements for a 70 kg human adult. Prospects for cultivating young vegetative quinoa in Mediterranean countries as a new sustainable, protein-rich winter leafy crop are therefore high, as supported by its high protein yields and quality, and its requirement for only scant irrigation. Further studies should examine economic and other agrotechnical parameters toward the geographical distribution and expansion of young vegetative quinoa cultivation.

plant biology↗

bioRxiv2019

Dose-specific effectiveness of 7- and 13-valent pneumococcal conjugate vaccines against vaccine-serotype Streptococcus pneumoniae colonization: a matched, case-control study

BackgroundReduced-dose pneumococcal conjugate vaccine (PCV) schedules are under consideration in countries where children are currently recommended to receive three PCV doses. However, dose-specific PCV effectiveness against vaccine-serotype colonization is uncertain. MethodsFrom 2009-2016, we conducted surveillance of pneumococcal carriage in southern Israel, where PCV is administered at ages 2, 4, and 12 months (2+1 schedule). We obtained nasopharyngeal swabs and vaccination histories from 4245 children ages 0-59 months without symptoms of diseases that could be caused by pneumococci. In a case-control analysis, we measured protection against vaccine-serotype colonization as one minus the matched odds ratio for PCV doses received. ResultsAt ages 5-12 months, a second PCV7/13 dose increased protection against PCV7-serotype carriage from -23.6% (95%CI: -209.7-39.1%) to 27.1% (-69.2-64.5%), and a second PCV13 dose increased protection against carriage of all PCV13 serotypes from -54.8% (-404.3-39.1%) to 23.4% (- 128.5-67.1%). At ages 13-24 months, a third PCV7/13 dose increased protection against PCV7-serotype carriage from 32.4% (-8.4-58.0%) to 74.1% (58.4-84.6%), and a third PCV13 dose increased protection against carriage of all PCV13 serotypes from -50.0% (-194.0-42.7%) to 49.7% (15.8-83.3%). On average, each PCV13 dose conferred 37.7% (7.0-61.8%) greater protection against carriage of serotypes 1, 5, 6A, 7F, and 19A than carriage of serotype 3. PCV13-derived protection against carriage of serotypes 1, 5, 6A, 7F, and 19A was equivalent to PCV7/13-derived protection against carriage of PCV7 serotypes. ConclusionsIn a setting implementing a 2+1 PCV schedule, protection against vaccine-serotype colonization is sustained primarily by the third dose.

epidemiology↗

bioRxiv2018

Decline in pneumococcal disease in unimmunized adults is associated with vaccine-associated protection against colonization in toddlers and preschool-aged children

Vaccinating children with pneumococcal conjugate vaccines disrupts transmission, reducing disease rates in unvaccinated adults. When considering changes in vaccination strategies (e.g., removing doses), it is critical to understand which groups of children contribute most to transmission. We used data from Israel to evaluate how the build-up of vaccine-associated immunity in children was associated with declines in IPD due to vaccine-targeted serotypes in unimmunized adults. Data on vaccine uptake and prevalence of colonization with PCV-targeted serotypes were obtained from a unique study conducted among children visiting an emergency department in southern Israel and from surveys of colonization from central Israel. Data on invasive pneumococcal disease in adults were obtained from a nationwide surveillance study. We compared the trajectory of decline of IPD due to PCV-targeted serotypes in adults with the trajectory of decline of colonization prevalence and trajectory of increase in vaccine-derived protection against pneumococcal carriage among different age groupings of children. The declines in IPD in adults were most closely associated with the declines in colonization and increased vaccination coverage in children in the range of 36-59 months of age. This suggests that preschool-aged children, rather than infants, are responsible for maintaining the indirect benefits of PCVs.

epidemiology↗

bioRxiv2017

Pneumococcal phenotype and interaction with nontypeable Haemophilus influenzae as determinants of otitis media progression

BackgroundAll-cause otitis media (OM) incidence has declined in numerous settings following introduction of pneumococcal conjugate vaccines (PCVs) despite increases in carriage of non-vaccine pneumococcal serotypes escaping immune pressure. To understand the basis for declining incidence, we assessed the intrinsic capacity of pneumococcal serotypes to cause OM independently and in polymicrobial infections involving nontypeable Haemophilus influenzae (NTHi) using samples obtained from middle ear fluid and nasopharyngeal cultures before PCV7/13 rollout.\n\nMethodsData included OM episodes (11,811) submitted for cultures during a 10-year prospective study in southern Israel and nasopharyngeal samples (1588) from unvaccinated asymptomatic children in the same population. We compared pneumococcal serotype diversity across carriage and disease isolates with and without NTHi co-isolation. We also measured associations between pneumococcal phenotype and rate of progression from colonization to OM in the presence and absence of NTHi.\n\nResultsWhereas pneumococcal serotype diversity in single-species OM is lower than in single-species colonization, serotype diversity does not differ significantly between colonization and OM in mixed-species episodes. Serotypes differed roughly 100-fold in progression rates, and these differences were attenuated in polymicrobial episodes. Vaccine-serotype pneumococci had higher rates of progression than non-vaccine serotypes. While serotype invasiveness was a weak predictor of OM progression rate, efficient capsular metabolic properties--traditionally thought to serve as an advantage in colonization--predicted an enhanced rate of progression to complex OM.\n\nConclusionsThe lower capacity of non-vaccine serotypes to cause OM may partially account for reductions in all-cause OM incidence despite serotype replacement in carriage following rollout of PCVs.

epidemiology↗