Red algae and their use in papermaking

Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps.

Subtidal benthic heterogeneity: flow environment modification and impacts on marine algal community structure and morphology

The shallow subtidal zone of rocky coastlines is a highly dynamic environment characterized by micro- and macroscopic benthic structures that alter the ambient flow environment, creating "flow microhabitats." We examined the impact of macroscopic benthic structure on the maximum flow speeds and the corresponding macroalgal community cover and morphological diversity observed in response to microhabitats in both exposed and sheltered near-shore sites. Flow speeds were reduced by a factor of 2 within crevices and also in the flow-shadow of protruding rock substrate when compared to neighboring unobstructed planar microhabitats. Algal communities within crevices and in the wake of protrusions were found to have greater cover of foliose red algal species compared to horizontal microhabitats in exposed sites, but reduced cover of these species in sheltered sites. The morphologies of two rhodophytes common to all microhabitats, Chondracanthus spinosus and Pterocladiella capillacea, were examined at both exposed and sheltered sites. Exposed horizontal morphotypes of both species were generally smaller and streamlined, whereas thalli from within crevices and in the wake of protrusions were larger and bushier. We conclude that algal cover and morphology is affected by the alteration in flow around both protruding bodies and crevices when compared to unobstructed sites.

Structure and origin of the natural halogenated monoterpene MHC-1 and its concentrations in marine mammals and fish

The halogenated natural product previously named mixed-halogenated compound 1 (MHC-1) was isolated from the red seaweed Plocamium cartilagineum harvested in Helgoland, Germany. A total of 1.9 mg of pure MHC-1 was obtained from 1g air-dried seaweed. The 1H and 13C NMR data matched those reported for a natural monoterpene isolated from this species. Thus, the structure of MHC-1 was established to be (1R,2S,4R,5R,1'E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(2'-chloroethenyl)-5-methylcyclohexane. Moreover, the isolated monoterpene proved to be identical with the compound previously detected in marine mammals and fish from different locations. In addition we examined two samples of P. cartilagineum from Ireland and from the Antarctic; however MHC-1 was only present at low levels. Not only the concentrations were lower but also the pattern of polybrominated compounds differed from MHC-1. A calibrated solution of MHC-1 was used to determine correct concentrations from samples where previously only estimates existed relative to the gas chromatography-electron capture detector (GC/ECD) response of trans-chlordane, which underrated the MHC-1 concentrations by more than factor 2. The highest MHC-1 concentration determined to date in marine mammals is 0.14 mg kg(-1) blubber. Significantly higher MHC-1 concentrations were determined in farmed fish with up to 2.2 mg kg(-1) lipids. The samples with high concentrations of MHC-1 have in common that they were collected in proximity of the natural habitats of P. cartilagineum.

[Studies on chemical constitutes of Acantophora spicifera]

OBJECTIVE

To study the chemical constitutes of Acantophora spicifera.

METHOD

Compounds were isolated by normal phase silica gel and Sephadex LH-20 gel column chromatography, and reverse-phase HPLC, as well as recrystallization. Their structures were elucidated by spectroscopic methods.

RESULT

Seven compounds were isolated from A. spicifera and their structures were identified as aplysin (1), loloilide (2), (R)-(-)-dehydrovomifoliol (3), uracil (4), thymine (5), 1-methoxy-4-(1-propenyl) benzene (6).

CONCLUSION

The compounds were obtained from this genus for the first time. Compound 6 was firstly obtained from marine organisms.

Antiviral activity of the marine alga Symphyocladia latiuscula against herpes simplex virus (HSV-1) in vitro and its therapeutic efficacy against HSV-1 infection in mice

The antiviral activities of extracts from 5 species of marine algae collected at Haeundae (Pusan, Korea), were examined using plaque reduction assays. Although the activity of a methanol (MeOH) extract of Sargassum ringoldianum (Sargassaceae) was the most potent against several types of viruses, it was also cytotoxic. A MeOH extract of Symphyocladia latiuscula (Rhodomelaceae) and its fractions exhibited antiviral activities against acyclovir (ACV) and phosphonoacetic acid (PAA)-resistant (AP(r)) herpes simplex type 1 (HSV-1), thymidine kinase (TK(-)) deficient HSV-1 and wild type HSV-1 in vitro without cytotoxicity. The major component, 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (TDB) of a CH(2)Cl(2)-soluble fraction was active against wild type HSV-1, as well as AP(r) HSV-1 and TK(-) HSV-1 (IC(50) values of 5.48, 4.81 and 23.3 microg/ml, respectively). The therapeutic effectiveness of the MeOH extract and TDB from S. latiuscula was further examined in BALB/c mice that were cutaneously infected with HSV-1 strain 7401H. Three daily oral administrations of the MeOH extract and TDB significantly delayed the appearance of score 2 skin lesions (local vesicles) and limited the development of further score 6 (mild zosteriform) lesions in infected mice without toxicity compared with controls. In addition, TDB suppressed virus yields in the brain and skin. Therefore TDB should be a promising anti HSV agent.

Algal species and light microenvironment in a low-pH, geothermal microbial mat community

Unicellular algae are the predominant microbial mat-forming phototrophs in the extreme environments of acidic geothermal springs. The ecology of these algae is not well known because concepts of species composition are inferred from cultivated isolates and microscopic observations, methods known to provide incomplete and inaccurate assessments of species in situ. We used sequence analysis of 18S rRNA genes PCR amplified from mat samples from different seasons and different temperatures along a thermal gradient to identify algae in an often-studied acidic (pH 2.7) geothermal creek in Yellowstone National Park. Fiber-optic microprobes were used to show that light for algal photosynthesis is attenuated to < 1% over the 1-mm surface interval of the mat. Three algal sequences were detected, and each was present year-round. A Cyanidioschyzon merolae sequence was predominant at temperatures of > or = 49 degrees C. A Chlorella protothecoides var. acidicola sequence and a Paradoxia multisita-like sequence were predominant at temperatures of < or = 39 degrees C.

Geobiology of a microbial endolithic community in the Yellowstone geothermal environment

The endolithic environment, the pore space of rocks, is a ubiquitous habitat for microorganisms on the Earth and is an important target of the search for life elsewhere in the Solar System. Photosynthetic, endolithic microbial communities commonly inhabit the outer millimetres to centimetres of all rocks exposed to the Earth's surface. In the most extreme terrestrial climates, such as hot and cold deserts, endolithic microorganisms are often the main form of life. The endolithic microhabitat gives protection from intense solar radiation and desiccation, and it provides mineral nutrients, rock moisture and growth surfaces. Here we describe the discovery and identification of the constituents of an extremely acidic (pH 1) endolithic microbial community inhabiting the pore space of rocks in the geothermal environment of Yellowstone National Park, USA. Subjected to silica mineralization, such endolithic communities constitute biomarkers that can become fossilized and potentially preserved in the geological record. Remnants of these communities could serve as biosignatures and provide important clues about ancient life associated with geothermal environments on the Earth or elsewhere in the Solar System.

Source bioaerosol concentration and rRNA gene-based identification of microorganisms aerosolized at a flood irrigation wastewater reuse site

Reuse of partially treated domestic wastewater for agricultural irrigation is a growing practice in arid regions throughout the world. A field sampling campaign to determine bioaerosol concentration, culturability, and identity at various wind speeds was conducted at a flooded wastewater irrigation site in Mexicali, Baja California, Mexico. Direct fluorescent microscopy measurements for total microorganisms, culture-based assays for heterotrophs and gram-negative enteric bacteria, and small-subunit rRNA gene-based cloning were used for microbial characterizations of aerosols and effluent wastewater samples. Bioaerosol results were divided into two wind speed regimens: (i) below 1.9 m/s, average speed 0.5 m/s, and (ii) above 1.9 m/s, average speed 4.5 m/s. Average air-borne concentration of total microorganisms, culturable heterotrophs, and gram-negative enteric bacteria were, respectively, 1.1, 4.2, and 6.2 orders of magnitude greater during the high-wind-speed regimen. Small-subunit rRNA gene clone libraries processed from samples from air and the irrigation effluent wastewater during a high-wind sampling event indicate that the majority of air clone sequences were more than 98% similar to clone sequences retrieved from the effluent wastewater sample. Overall results indicate that wind is a potential aerosolization mechanism of viable wastewater microorganisms at flood irrigation sites.

Source bioaerosol concentration and rRNA gene-based identification of microorganisms aerosolized at a flood irrigation wastewater reuse site

Reuse of partially treated domestic wastewater for agricultural irrigation is a growing practice in arid regions throughout the world. A field sampling campaign to determine bioaerosol concentration, culturability, and identity at various wind speeds was conducted at a flooded wastewater irrigation site in Mexicali, Baja California, Mexico. Direct fluorescent microscopy measurements for total microorganisms, culture-based assays for heterotrophs and gram-negative enteric bacteria, and small-subunit rRNA gene-based cloning were used for microbial characterizations of aerosols and effluent wastewater samples. Bioaerosol results were divided into two wind speed regimens: (i) below 1.9 m/s, average speed 0.5 m/s, and (ii) above 1.9 m/s, average speed 4.5 m/s. Average air-borne concentration of total microorganisms, culturable heterotrophs, and gram-negative enteric bacteria were, respectively, 1.1, 4.2, and 6.2 orders of magnitude greater during the high-wind-speed regimen. Small-subunit rRNA gene clone libraries processed from samples from air and the irrigation effluent wastewater during a high-wind sampling event indicate that the majority of air clone sequences were more than 98% similar to clone sequences retrieved from the effluent wastewater sample. Overall results indicate that wind is a potential aerosolization mechanism of viable wastewater microorganisms at flood irrigation sites.

Surface gas-exchange processes of snow algae

The red-colored chlorophyte Chlamydomonas nivalis is commonly found in summer snowfields. We used a modified Li-Cor gas-exchange system to investigate surface gas-exchange characteristics of snow colonized by this alga, finding rates of CO(2) uptake up to 0.3 micromol.m(-2).s(-1) in dense algal blooms. Experiments varying the irradiance resulted in light curves that resembled those of the leaves of higher plants. Red light was more effective than white and much more effective than green or blue, because of the red astaxanthin that surrounds and masks the algal chloroplasts. Integrating daily course measurements of gas exchange showed CO(2) uptake around 2,300 micromol.m(-2).day(-1) in heavily colonized patches, indicating that summer snowfields can be surprisingly productive.

Acid-fast bodies in faecal smears stained by the modified Ziehl-Neelsen technique

The modified Ziehl-Neelsen (ZN) stain has proved useful in the laboratory diagnosis of cryptosporidiosis and, more recently, for the laboratory diagnosis of cyclospora. Apart from cryptosporidia and cyclospora, many other organisms and artefacts are present in faeces, and may be seen in faecal smears stained by the modified ZN method. Described here is the presence of such organisms and artefacts in faecal samples submitted to the routine microbiology laboratory of a district general hospital. Over 6000 faecal smears were examined using the modified ZN method, with an incidence of cyclospora and cryptosporidium of approximately 0.1% and 1%, respectively. Other organisms and artefacts were observed, with an incidence ranging from 0.1% to 1%. It is emphasised that the identification of known gastrointestinal tract pathogens should not rely solely on the results of their staining reactions. It is essential that criteria such as morphology and size be taken into account to differentiate organisms with similar staining reactions.

Snow algae of the Sierra Nevada, Spain, and High Atlas mountains of Morocco

Snow algae (Chlorophyta) are reported from the Sierra Nevada mountains in southern Spain and the High Atlas mountains of Morocco. Populations of the snow algae Chlamydomonas sp., coloring the snow orange-red, were collected from Pico de Veleta, Spain, while snow samples from Mt. Neltner in the High Atlas mountains, contained resting spores of an orange-green colored Chloromonas sp. Other microbes observed in snow samples include bacteria, fungi, heterotrophic euglenids, diatoms, nematodes, and heterotrophic mastigotes (flagellated protists). This is the first report of snow algae from the Sierra Nevada mountains of Spain and from the Afro-alpine environment.

Purification and properties of adenosine 5'-phosphosulfate deaminating enzyme from marine macroalga Gloiopeltis furcata

An enzyme which catalyzed the hydrolytic removal of the 6-amino group of adenosine 5'-phosphosulfate (APS) into inosine 5'-phosphosulfate was purified from the marine red macroalga Gloiopeltis furcata by means of salt fractionation, affinity, anion-exchange, and hydrophobic interaction chromatographies. The native enzyme had a Mr of about 285,000. Dissociation yielded a form with a Mr of about 70,000. The enzyme catalyzed the irreversible deamination of adenosine and its 5'-substituted compounds in addition to APS. Thus the enzyme seemed to be a nonspecific adenine nucleotide deaminase. Some properties were determined and compared with those of other nonspecific adenine nucleotide deaminases.

Cyanobacteria or rhodophyta? Interpretation of a precambrian microfossil

Discovery and interpretation of a filamentous microfossil from the late Proterozoic Narssârssuk Formation in northwest Greenland approximately 770 Ma is reported here. This microfossil is preserved as a single occurrence in a silicified carbonate sequence containing stromatolitic laminae. Based on the absence of other occurrences and its microstratigraphic association with planktonic microfossils, the microfossil is interpreted as allochthonous. The microfossil is similar to two extant taxa representing different kingdoms: one prokaryote, Johannesbaptistia pellucida (cyanobacteria) and one eukaryote, Bangia sp. (rhodophytes). Definitive identification, due to the lack of distinctive morphology, could not be made.