Spatial variation of biomass of seaweed assemblages in the temperate-tropical transition zone of Baja California Peninsula, Mexico

Biomass changes of seaweed assemblages in four locations in a temperate-tropical transition zone were analyzed between October 1996 and August 1997. Locations with lower temperature, a high index of upwelling, and high quantities of hard substrate presented the largest values of biomass of seaweed (El Cardoncito (7.2 kg m-2), and Las Boyitas (6.2 kg m-2)) and the biggest quantity of species of temperate affinity. Conversely, El Datilito (0.366 kg m-2), with a higher temperature, no evidence of upwelling, sandy substrate, and located in protected shallow waters, presented the lowest values of biomass and the lowest proportion of temperate affinity seaweed. The PCA and similarity analysis showed a close relationship between El Cardoncito and Las Boyitas. El Datilito was categorized as independent location, while Chester Rock (4.3 kg m-2) displayed intermediate characteristics. The close relationship observed between the first two locations can be explained by the similarity of their high biomass and physiographic and environmental characteristics. El Datilito has very different physiographic and environmental characteristics and a very low biomass.Se analizaron los cambios en la biomasa de las asociaciones de macroalgas en una zona de transición templadotropical entre octubre de 1996 y agosto de 1997 en cuatro localidades. Las localidades con la temperatura más baja, alto índice de surgencias y mayor dominancia de sustrato duro presentaron los mayores valores de biomasa de macroalgas (El Cardoncito (7.2 kg m-2) y Las Boyitas (6.2 kg m-2)) y la mayor cantidad de especies de afinidad templada. Por el contrario El Datilito (0.366 kg m-2) en donde la temperatura fue más alta, no hay evidencia de surgencias, el sustrato es arenoso, es un área más somera y protegida, presentó el menor valor de biomasa de macroalgas y la menor proporción de algas de afinidad templada. Los análisis de componentes principales y similaridad mostraron una estrecha relación entre El Cardoncito y Las Boyitas. El Datilito se mantuvo como una localidad independiente, mientras que Chester Rock (4.3 kg m-2) tuvo características intermedias de biomasa de algas. La estrecha relación entre las dos primeras localidades puede explicarse por la similaridad en términos de su alta biomasa aunado con las características fisiográficas y ambientales que presentaron. El Datilito presentó características fisiográficas y ambientales muy diferentes a las demás localidades, además de tener muy poca biomasa de macroalgas

Toxicological and therapeutic evaluation of the algae Macrocystis pyrifera (Phaeophyceae) in rodents

Macrocystis pyrifera is a giant brown seaweed with high nutritional content, used as a dietary supplement in some farm animals. It contains fucoidan which has a pharmacological effect on lipids and glucose metabolism. Some brown seaweeds can bioaccumulate toxic elements in their cell wall, representing a problem if toxicity tests that guarantee the safety of their consumption are not done. M. pyrifera, does not present toxicological studies that guarantee its safety. This work aimed to perform the acute and subchronic toxicological evaluation of M. pyrifera in rodents as well as to determine its possible therapeutic effect. Fronds of M. pyrifera were collected in Baja California Sur, Mexico, for drying and obtaining algae flour. The acute toxicity test LD50 was performed in C57BL / 6 male mice (25 ± 3 g) for 7 days, finding an LD50 greater than 10 g kg-1. Subchronic toxicity was determined for 121 days in adult male Sprague Dawley rats (98 ± 2 g), during which the experimental animals showed no signs of toxicity, or changes in the hematological, biochemical and histopathological parameters of the organs. The reactive oxygen species, lipid peroxidation or glutathione ratio were not different from the control group. A therapeutic effect on the regulation of body weight and a hypolipidemic effect (triacylglycerides: 82.27 ± 5.55 mg dl-1, cholesterol: 98.61 ± 6.48 mg dl-1) were found. It is concluded that, under the conditions in which this study was developed, the consumption of M. pyrifera as a functional ingredient is safe

Microbiota gastrointestinal y síndrome de intestino irritable

We thank García-Mazcorro et al.1 for their interest and comments on completely agree with them concerning the term intestinal «flora». Microbiota is the correct word, defined as the community of living microorganisms residing in a determined ecological niche, and we use it, not only in the title, but throughout the article (79 times to be exact), whereas the less precise but commonly used flora is employed only 5 times.2 Secondly, the 16S ribosomal RNA (rRNA) gene is one of the components of the small subunit (30S) of the ribosome and is present in all bacteria and archaea. It is the genetic marker used in bacterial phylogenetic analysis and is widely used in an endless number of studies. This gene sequence is approximately 1,550 bp long and is composed of 9 highly variable regions or hypervariable regions flanked by constant regions. The differences in sequencing of these hypervariable regions make it possible to taxonomically identify the bacteria present in study samples (for example, in stools and intestinal mucosa).3 The «rrs» gene, also known as 16S ribosomal DNA or 16S rDNA, as mentioned in table 3 of our article, encodes 16S rRNA. Even though there are limitations in sequencing based on 16S rRNA, it continues to be the gold standard due to the extensive databases based on this marker. Illumina belongs to the «next generation» sequencing technologies that are limited by the length of the sequences they can provide, and so specific regions of the 16S rRNA gene must be selected in the analysis.3 Other sequencing strategies and equipment currently exist that were designed for completion and correction. Thirdly, the inability to absolutely establish the microbiota that is characteristic of IBS due to the factors mentioned by García-Mazcorro et al. is a fundamental aspect of our review.2 In fact, that was why we reached the conclusion that even though there is evidence that the intestinal microbiota is different in persons with IBS from that of normal subjects (level 3b evidence, grade B recommendation), it is not possible to establish a microbial composition that is specific for this disorder (level 3b evidence, grade B recommendation).2 On the other hand, we agree that the taxonomic levels found were not mentioned in some cases, but some of the studies reviewed only reported the differences in microbial groups. And finally, we agree that our already extensive review fell short of analyzing the use of probiotics, prebiotics, and even synbiotics, in the treatment of IBS, but we felt these topics should be the subject of another review. As a matter of fact, a very recent systematic review of the literature has reported that probiotics were superior to placebo due to a lower frequency of IBS symptom persistence (55.8% vs. 73.1%).4 In addition, probiotics were shown to be superior to placebo in the improvement of overall symptoms, abdominal pain, subjective abdominal bloating, and flatulence. Specifically, it was Bifidobacterium spp that showed a tendency toward the improvement of overall symptoms and abdominal pain, but determining which strain(s) will be the effective one(s) has yet to be established. The authors also found that there were very few studies on prebiotics and synbiotics.4 Another review found that B. infantis 35624 was effective in improving subjective bloating in IBS in general and B. animalis DN-173010 in patients with constipation predominant IBS (IBS-C).5 Furthermore, the relation between diet and the microbiota should also be analyzed. For example, low FODMAP (Fermentable Oligosaccharides Disaccharides, Monosaccharides, And Polyols) diets that improve IBS symptoms also appear to reduce the concentration and proportion of bifi-dobacteria in stools determined through fluorescence in situ hybridizatio

Composición y abundancia de florecimientos macroalgales y su relación con variables ambientales en una bahía subtropical en el Golfo de California

Background: In La Paz Bay macroalgae blooms have an important presence. Goal: Analyze the relationship of the most abundant macroalgae in algal blooms with environmental variability in a subtropical bay over two years. Methods: Temperature, salinity, nutrients (DIN, NT, PO4 -3 and PT) and macroalgae samples were taken every three months, during 2010 and 2011, at four sites with conspicuous growth of macroalgae. Total and mean biomass (wet weight) of important species was estimated by placing three transects perpendicular to the coast, divided into five equidistant points each. At each point four quadrants (0.25 m2 ) were placed randomly and macroalgae were manually collected. Statistical analyzes were performed to estimate significant differences between years, months and sites of the environmental variables, nutrients, and biomass. A principal component analysis was performed, to observe the relationship between biomass and environmental variables and nutrients. Results: Nine macroalgae species, plus one cyanoprokaryonte showed a biomass greater than 1 g m-2. Acanthophora spicifera, Caulerpa verticillata and Spyridia filamentosa were the most abundant species. A. spicifera and G. vermiculophylla were related with nutrient concentrations, and salinity. While Ulva ohnoi showed that it was not related either to environmental or nutrient concentrations. Conclusion: The bloom forming macroalgae A. spicifera, C. verticillata and S. filamentosa are consistent with genera previously reported as bloom-formers in nutrient-rich coastal waters.Antecedentes: En la Bahía de La Paz los florecimientos de macroalgas tienen una presencia importante. Objetivo: Analizar la relación de las macroalgas más abundantes en los florecimientos algales, con la variabilidad ambiental en una bahía costera a lo largo de dos años. Métodos: Se tomaron muestras de temperatura, salinidad, nutrientes (DIN, NT, PO4 -3 y PT) y macroalgas cada tres meses, durante 2010 y 2011, en cuatro sitios con crecimiento notorio de macroalgas. La biomasa total y media (peso húmedo) de las especies abundantes se estimó colocando tres transectos perpendiculares a la costa, divididos en cinco puntos equidistantes cada uno. En cada punto se colocaron aleatoriamente cuatro cuadrantes (0.25 m2 ) y se recolectaron manualmente las macroalgas. Se realizaron análisis estadísticos para estimar diferencias significativas entre años, meses y sitios de las variables ambientales, nutrientes y biomasa. Se realizó un análisis de componentes principales, con el fin de observar la relación entre la biomasa y las variables ambientales. Resultados: Nueve especies de macroalgas, más un cianoprocarionte presentaron una biomasa mayor a 1 g m-2. Acanthophora spicifera, Caulerpa verticillata y Spyridia filamentosa fueron las especies más abundantes. A. spicifera y G. vermiculophylla mostraron relación con las concentraciones de nutrientes y la salinidad. Mientras que, Ulva ohnoi no mostró relación con las concentraciones ambientales o de nutrientes. Conclusión: Las macroalgas que forman florecimientos A. spicifera, C. verticillata y S. filamentosa coinciden con los géneros previamente reportados como formadores de florecimientos en aguas costeras ricas en nutrientes

Development of a Semi-Field System for Contained Field Trials With Aedes Aegypti in Southern Mexico

Development of new genetic approaches to either interfere with the ability of mosquitoes to transmit dengue virus or to reduce vector population density requires progressive evaluation from the laboratory to contained field trials, before open field release. Trials in contained outdoor facilities are an important part of this process because they can be used to evaluate the effectiveness and reliability of modified strains in settings that include natural environmental variations without releasing mosquitoes into the open field. We describe a simple and cost-effective semi-field system designed to study Aedes aegypti carrying a dominant lethal gene (fsRIDL) in semi-field conditions. We provide a protocol for establishing, maintaining, and monitoring stable Ae. aegypti population densities inside field cages

Macroalgas marinas bentónicas de Isla Gudalupe, Baja California, México

Background. The last floristic survey of marine algae species from Guadalupe Island was published in the 1980s, including a summary of surveys from collections dating back to the beginning of the past century. Goals. To update the species inventory and analyze the macroalgae community on Guadalupe Island. Methods. Four sampling procedures were undertaken, during January, April, and October 2013, and May 2014, from intertidal and subtidal zones, at depths of between 10 and 18m, depending on the locality. Results. 102 species were identified as representatives of the threemain taxonomic divisions; 14 species belonging to Chlorophyta, 29 to Ochrophyta, and 59 to Rhodophyta, related to 39 families and 65 genres. Of the organisms found at a specific level, 30 are new records, 13 are taxonomically synonymous, and 59 correspond to previous registries. The Margalef index shows that the highest biologic richness occurred in May 2014, as while the highest diversity also appeared in that same month, as the Shannon-Wiener index indicates. Data were statistically evaluated with the PERMANOVA analysis, showing statistical differences between the analyzed factors(depth, season, zone, and locality), thus demonstrating high heterogeneity at the localities, mainly between the northern and western areas of the island. Conclusions. Guadalupe Island has high species richness and diversity. In accordance to SIMPER analysis, the species that contribute most to the qualitative differences found in the analyzed factors are Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata, and Padina durvillei.Antecedentes. El último inventario florístico de algas marinas de Isla Guadalupe se publicó en la década de 1980, e incluye una recopilación de trabajos de colecciones de principios del siglo pasado. Objetivos. Realizar un inventario y un análisis actualizado de la comunidad de macroalgas de Isla Guadalupe. Métodos. Se efectuaron cuatro muestreos durante los meses de enero, abril y octubre del 2013 y mayo del 2014, en la zona intermareal y en la submareal, a 10 y 18 m de profundidad, dependiendo de la localidad. Resultados. En total se determinaron 102 especies, entre las que se encuentran representantes de las tres principales Divisiones taxonómicas: 14 especies de la División Chlorophyta, 29 especies de la División Ochrophyta y 59 especies de la División Rhodophyta, las cuales se relacionan con 39 familias y 65 géneros. De los organismos determinados a nivel específico, 30 corresponden a nuevos registros, 13 con sinonimia taxonómica y 59 especies están previamente registradas. De acuerdo con el índice de Margalef, durante mayo del 2014 se presentó la mayor riqueza biológica, en este mismo periodo, según el índice de Shannon-Wiener, se encontró una mayor diversidad. Los datos se analizaron estadísticamente con el análisis PERMANOVA, el cual mostró diferencias significativas entre los factores examinados de profundidad, temporada, zona y localidad de muestreo, lo que indica una alta heterogeneidad entre las localidades, principalmente entre la zona norte y la oeste de la isla. Conclusiones. Isla Guadalupepresenta una gran riqueza y diversidad biológica. De acuerdo con el análisis SIMPER, las especies que más contribuyen a las diferencias cualitativas de los factores analizados son Zonaria farlowii, Jania rosea, Sargassum palmeri, Dictyopteris undulata y Padina durvillei

Global shortage of technical agars: back to basics (resource management)

Bacteriological and technical agars are in short supply with potential consequences for research, public health, and clinical labs around the world. To diagnose bottlenecks and sustainability problems that may be putting the industry at risk, we analyzed the available time series for the global landings of Gelidium, the most important raw materials for the industry. Data on the harvest of Gelidium spp. have been reported since1912, when Japan was the only producer. After World War II the diversification of harvested species and producing countries resulted in a strong increase in global landings. Maximum harvest yields of almost 60,000 t year(-1) in the 1960s were sustained until the 1980s, after which landings decreased continuously to the present. In the 2010s, a reduction in the global production to about 25,000 t year(-1) was observed, which was lower than the yields of the 1950s. Landings by important producers such as Japan, Korea, Spain, and Portugal have collapsed. This is the ultimate cause of the present shortage of bacteriological and technical agars. However, an important factor at play is the concentration of the global landings of Gelidium in Morocco, as its relative contribution increased from 23% in the 1960s to the present 82%. Two specific bottlenecks were identified: restrictive export quotas of unprocessed Gelidium in favor of the national agar industry and resource management regulations that were apparently not enforced resulting in over-harvesting and resource decline. The global industry may well be dependent on resource management basics. Simple harvest statistics must be gathered such as the harvest effort and the variation of harvest yields along the harvest season. We discuss how this information is fundamental to manage the resource. The available harvest statistics are generally poor and limited and vary significantly among different sources of data. Probable confusions between dry and wet weight reporting and poor discrimination of the species harvested need to be resolved