A global drive to source additional and sustainable biomass for the production of protein has resulted in a renewed interest in the protein content of seaweeds. However, to determine accurately the potential of seaweeds as a source of protein requires reliable quantitative methods. This article systematically analysed the literature to assess the approaches and methods of protein determination and to provide an evidence-based conversion factor for nitrogen to protein that is specific to seaweeds. Almost 95 % of studies on seaweeds determined protein either by direct extraction procedures (42 % of all studies) or by applying an indirect nitrogen-to-protein conversion factor of 6.25 (52 % of all studies), with the latter as the most widely used method in the last 6 years. Meta-analysis of the true protein content, defined as the sum of the proteomic amino acids, demonstrated that direct extraction procedures underestimated protein content by 33 %, while the most commonly used indirect nitrogen-to-protein conversion factor of 6.25 over-estimated protein content by 43 %. We therefore determined whether a single nitrogen-to-protein conversion factor could be used for seaweeds and evaluated how robust this would be by analysing the variation in this factor for 103 species across 44 studies that span three phyla, multiple geographic regions and a range of nitrogen contents. An overall median nitrogen-to-protein conversion factor of 4.97 was established and an overall mean nitrogen-to-protein conversion factor of 4.76. We propose that the overall median value of 5 be used as the most accurate universal seaweed nitrogen-to-protein (SNP) conversion factor.

To determine the relative importance of two known serotypes of human rotavirus, we developed an enzyme-linked immunosorbent assay to differentiate serotype-specific rotavirus antigen and antibody. Using this technic, we studied the epidemiology of the two serotypes in acute gastroenteritis. Seventy-seven per cent of 414 rotavirus isolates were Type 2, and the remainder were Type 1. The serotype distribution was similar in specimens from children in Washington D.C., and other parts of the world. Sero-R OTAVIRUS is an important cause of gastroenteritis of infants and children in many parts of the world.'' 2 Because the virus does not grow effi-ci,ently in tissue culture, conventional neutralization "methods cannot be used to examine its serotypic variations.''' Recently, two human rotavirus serotypes were distinguished by complement fixation,' immune electron microscopy' and immunofluorescence. 6 The latter two methods are not practical for serotyping of large numbers of rotavirus-positive specimens whereas complement fixation is not sensitive enough for use with low-titered preparations. We recently described the technic of enzyme-linked immunosorbent assay for the detection of rotavirus antigen and antibody.'"" This assay is similar in design to radioimmunoassay but uses an enzyme instead of a radioactive isotope to quantitate binding of immunoglobulin. We modified the basic assay for detection of rotavirus serotypes and used this new procedure to study the epidemiology of these viruses. MATERIALS AND METHODS Specimens'Stool specimens containing rotavirus were collected from 278 in-il. nts and children with gastroenteritis living in the Washington, D.C., area. From January, 1974, to October, 1976, only hospitalized patients were studied, whereas from November, 1976, to May, 1978, specimens from both inpatients and outpatients were available. This population has been described in detail.' In addition, 136 rotaviruscontaining specimens were available from children with and without gastroenteritis from other localities throughout the world. Included were rotavirus-positive stool specimens obtained

As wild fish stocks decline worldwide, land-based fish rearing is likely to be of increasing relevance to feeding future human generations. Little is known about the structure and role of microbial communities in fish aquaculture, particularly at larval developmental stages where the fish microbiome develops and host animals are most susceptible to disease. We employed next-generation sequencing (NGS) of 16S rRNA gene reads amplified from total community DNA to reveal the structure of bacterial communities in a gilthead seabream (Sparus aurata) larviculture system. Early- (2 days after hatching) and late-stage (34 days after hatching) fish larvae presented remarkably divergent bacterial consortia, with the genera Pseudoalteromonas, Marinomonas, Acinetobacter, and Acidocella (besides several unclassified Alphaproteobacteria) dominating the former, and Actinobacillus, Streptococcus, Massilia, Paracoccus, and Pseudomonas being prevalent in the latter. A significant reduction in rearing-water bacterial diversity was observed during the larviculture trial, characterized by higher abundance of the Cryomorphaceae family (Bacteroidetes), known to populate microniches with high organic load, in late-stage rearing water in comparison with early-stage rearing-water. Furthermore, we observed the recruitment, into host tissues, of several bacterial phylotypes—including putative pathogens as well as mutualists—that were detected at negligible densities in rearing-water or in the live feed (i.e., rotifers and artemia). These results suggest that, besides host-driven selective forces, both the live feed and the surrounding rearing environment contribute to shaping the microbiome of farmed gilthead sea-bream larvae, and that a differential establishment of host-associated bacteria takes place during larval development.

Longitudinal data on Giardia excretion, diarrheal disease, and physical growth during the first 3 yr of life collected more than 20 yr ago in 45 Guatemalan children were analyzed. This report describes the natural history of this infection and estimates its effects on growth. All children had at least one Giardia infection, prevalence and incidence rates reaching 20.2% and 5.3%, respectively by the end of the third year. The mean number of Giardia infections per child increased from 0.7 in the first to 3.6 in the third year. More than 40% of these infections lasted 2-6 wk or more and were commonly associated with diarrhea. Weight velocity was significantly lower in the second year of life in Giardia-infected than in Giardia-negative children (p = 0.03). The duration of Giardia episodes and their association with diarrhea appeared to be the most important factors associated with growth disturbance. Although simultaneous infection with other enteropathogens occurred in many children, our findings suggest that Giardia infection may have independent deleterious effects on children's growth.