Antiviral polysaccharides isolated from Hong Kong brown seaweed <Emphasis Type="Italic">Hydroclathrus clathratus</Emphasis>

Two relatively pure polysaccharides H3-a1 and H3-b1 had been isolated from the brown seaweed Hydroclathrus clathratus. They were characterized by HPLC, ultraviolet scanning, gas chromatography, infrared spectroscopy and elemental analysis, and shown to be two different sulfated polysaccharides with different monosaccharide content, but both with high relative molecular mass. They contained some proteins and uronic acid respectively. The sulfate content and bioactivity of these polysaccharides varied during purification. The fractions derived from the hot water extract also exhibited low anticoagulant effect. This is the first time that the antiherpetic and anticoagulant activities were evaluated for the polysaccharides from the Hong Kong brown seaweed Hydroclathrus clathratus.     

Bioactive volatile compounds from marine algae: feeding attractants

Chemical communications play an important role in plants, fungi, and algae. Volatile organic compounds in marine algae are released into the seawater. These compounds play a role as either pheromones or allelochemicals. We observed that the turbinid gastropod Lunella coronata coreensis inhabits the intertidal zone and often grazes the green alga Ulva pertusa. Feeding tests and feeding preference studies were performed with green, brown and red algae or by using the powdered freeze-dried seaweed in agar. The snails fed on U. pertusa preferentially compared to the other marine algae, and recognized chemoreception compounds from the alga but not their structural or morphological differences. From feeding tests using artificial foods, it is suggested that the feeding attractants are in the essential oil of the alga U. pertusa.     

The potential of bacteria isolated from ruminal contents of seaweed‐eating North Ronaldsay sheep to hydrolyse seaweed components and produce methane by anaerobic digestion in vitro

The production of methane biofuel from seaweeds is limited by the hydrolysis of polysaccharides. The rumen microbiota of seaweed‐eating North Ronaldsay sheep was studied for polysaccharidic bacterial isolates degrading brown‐seaweed polysaccharides. Only nine isolates out of 65 utilized > 90% of the polysaccharide they were isolated on. The nine isolates (eight Prevotella spp. and one Clostridium butyricum) utilized whole Laminaria hyperborea extract and a range of seaweed polysaccharides, including alginate (seven out of nine isolates), laminarin and carboxymethylcellulose (eight out of nine isolates); while two out of nine isolates additionally hydrolysed fucoidan to some extent. Crude enzyme extracts from three of the isolates studied further had diverse glycosidases and polysaccharidase activities; particularly against laminarin and alginate (two isolates were shown to have alginate lyase activity) and notably fucoidan and carageenan (one isolate). In serial culture rumen microbiota hydrolysed a range of seaweed polysaccharides (fucoidan to a notably lesser degree) and homogenates of L. hyperborea, mixed Fucus spp. and Ascophyllum nodosum to produce methane and acetate. The rumen microbiota and isolates represent potential adjunct organisms or enzymes which may improve hydrolysis of seaweed components and thus improve the efficiency of seaweed anaerobic digestion for methane biofuel production.     

Advances in Seaweed Aquaculture Among Pacific Island Countries

Recent developments in the seaweed aquaculture industries of Pacific islands are reviewed from the perspective of technical, production, geographic, marketing, species-diversification, socio-economic and institutional-support advances. Successful commercial aquaculture of seaweeds in the Pacific island region is presently based on two species, Kappaphycus alvarezii in Kiribati, Fiji and Solomon Islands, and Cladosiphon sp. in Tonga. It is possible that other candidate species could be considered for aquaculture for food (e.g. Caulerpa racemosa or Meristotheca procumbens) or extraction of agar (Gracilaria), although further research on the technical feasibility of aquaculture methods to produce sufficient tonnage, and particularly on their marketing, is needed. While the Pacific island region may be environmentally ideal for seaweed aquaculture, the limitations of distance from main centres and distance from markets, vulnerability to world price fluctuations, and socio-economic issues, make it unlikely that the Pacific Island region will ever rival the scale of Asian seaweed production. Regional seaweed farming can nevertheless make a useful contribution to supplement other sources of income, and can be an important economic boost for isolated outer islands where few alternative income-generating opportunities exist.     

The sclerotia of Coprinus lagopus

Summary Sclerotia of Coprinus lagopus were produced in the laboratory and observed microscopically from initiation to maturity. Isolated bulbous hyphal cells appeared below or on the agar surface as the primary sclerotial initials. Short interhyphal cells had expanded lateral walls and increased in number at their isolated locations, and were surrounded by a thick network of normal mycelium. Increasing in numbers, the bulbous cells developed a tightly compact colony devoid of agar if submerged below the agar surface and lacked normal hyphal filaments. The outer cells thickened formed cell lumina and developed as a protective rind to the mature sclerotium.     

SULFUR AND THE TOXICITY OF THE RED ALGA CERAMIUM RUBRUM TO BACILLUS SUBTILIS1,2

Crystalline sulfur has been isolated from the red seaweed Ceramium rubrum and shown to be responsible for the toxicity of this alga to the growth of Bacillus subtilis. This alga was unusual in that it contained a much higher free sulfur content than other red and brown algae tested.     

First Report of Rhizoctonia solani AG‐7 on Cotton in Egypt

Eighty‐two isolates of Rhizoctonia solani were recorded from roots of naturally‐infected seedlings of the Egyptian cotton (Gossypium barbadense L.). Anastomosis groups (AGs) of the isolates were determined by using 13 different AGs testers. Three (3.7%) of the isolates were identified as R. solani AG7, while the remaining isolates were belonging to the AG 2‐1, AG4 and AG5. The identification of the three isolates was based on the frequency of the C2 reaction with the AG7 tester isolate. No fusion was observed between AG7 and isolates representing the other 13 AGs. Colonies of AG7 isolates grown on potato dextrose agar (PDA), malt yeast agar (MYA) and melt peptone agar (MPA) were brown to dark brown with aerial mycelium and sclerotia. The isolates had pitted sclerotial clusters and brownish exudates after 21 days of culturing on PDA, but without clear zonation. Pathogenicity test under greenhouse conditions revealed that AG7 caused the common symptoms of damping–off, which included seed rot, lesions on the hypocotyls and root rot.     

Agar Processed from Gracilaria foliifera of Florida

Agar producing a firm gel with specific rheological properties as well as a good commercial value was processed from Gracilaria foliifera (Forsskal) Børgesen, a red alga harvested along the Florida west coast. The alkali pretreatment of the seaweed based on the Funaki-Kojima’s method was applied before the process of agar extraction. The chemical and physical properties of the processed agar were compared with other typical agar experimentally processed.     

Production of bioflavor by regeneration from protoplasts of Ulva pertusa (Ulvales,Chlorophyta)

Protoplasts were isolated from thalli of Ulva pertusa using a mixed enzyme solution of 2.0% Cellulase Onozuka R-10, 2.0% Macerozyme R-10, and 2.0% Driselase. Isolated protoplasts regenerated cell walls, developed into thalli, and propagated in large numbers under aeration in the preparative scale-culture system. Typical bioflavor compounds produced from the regenerated plants, as well as from field-collected plants, were found to be long chain aldehydes, which gave a typical seaweed odor. The long chain aldehydes were formed enzymatically from unsaturated fatty acids and released into the culture fluid. A Percoll/mannitol discontinuous density gradient separation of the heterogeneous protoplasts led to a selection of cell lines with high production of bioflavor. The cells that regenerated from protoplasts were immobilized by polymer matrices such as alginate, -carrageenan, agarose, and agar. Living cells entrapped in alginate beads in aerated cultures survived best. However, the beads started to breakdown after two months. The immobilized cells demonstrated a higher bioflavor production than did the cultured cells.     

Evaluation of kappa carrageenan as a substitute for agar in microbiological media

Seventy-one samples of the colloid kappacarrageenan extracted from 12 seaweed species were subjected to a number of standard physical demands of solid bacteriological culture media. All samples had a lower melting temperature (less than 67° C) than agar and a gelling (setting) temperature between 16° C and 51° C, some the same and others lower or higher than agar. Temperature spreads were narrow (ca 10° C) to broad (ca 30° C), depending on the seaweed source, but none were as broad as that of agar (ca 40° C). The majority of commercially prepared samples held a slant when incubated at 37° C, but California seaweed colloids were best at 28° C in this test. The majority of samples released little to no water of syneresis in slant tests as well as in plates. Some plates prepared with the colloid were crystal clear as compared to agar plates. All test microorganisms grew as well on kappa-carrageenan media as on agar media. Some media responses could be attributable to the seaweed species, but others could be traced to chemical extraction methods and modification of the colloid.     

Isolation and molecular characterization of <Emphasis Type="Italic">Xylella fastidiosa</Emphasis> from coffee plants in Costa Rica

Coffee plants exhibiting a range of symptoms including mild to severe curling of leaf margins, chlorosis and deformation of leaves, stunting of plants, shortening of internodes, and dieback of branches have been reported since 1995 in several regions of Costa Rica’s Central Valley. The symptoms are referred to by coffee producers in Costa Rica as “crespera” disease and have been associated with the presence of the bacterium Xylella fastidiosa. Coffee plants determined to be infected by the bacterium by enzyme linked immunosorbent assay (ELISA), were used for both transmission electron microscopy (TEM) and for isolation of the bacterium in PW broth or agar. Petioles examined by TEM contained rod-shaped bacteria inside the xylem vessels. The bacteria measured 0.3 to 0.5 μm in width and 1.5 to 3.0 μm in length, and had rippled cell walls 10 to 40 nm in thickness, typical of X. fastidiosa. Small, circular, dome-shaped colonies were observed 7 to 26 days after plating of plant extracts on PW agar. The colonies were comprised of Gram-negative rods of variable length and a characteristic slight longitudinal bending. TEM of the isolated bacteria showed characteristic rippled cell walls, similar to those observed in plant tissue. ELISA and PCR with specific primer pairs 272-l-int/272-2-int and RST31/RST33 confirmed the identity of the isolated bacteria as X. fastidiosa. RFLP analysis of the amplification products revealed diversity within X. fastidiosa strains from Costa Rica and suggest closer genetic proximity to strains from the United States of America than to other coffee or citrus strains from Brazil.     

Phycological research in the development of the Chinese seaweed industry

The term seaweed industry is employed in a broad sense and includes production both of commercial seaweeds such as Laminaria and Porphyra by phycoculture and of processed seaweed products, such as algin, agar and carrageenan.Before the founding of the People's Republic, China had a very insignificant seaweed industry, producing small quantities of the purple laver Porphyra and the glueweed Gloiopeltis by the primitive rock-cleaning method and the kelps Laminaria and Undaria by the primitive stone-throwing method, both aiming at enhancing the growth of the wild seaweeds. Also, a small quantity of agar was manufactured by the traditional Japanese method of gelling, freezing, thawing and drying the product. The small production was not sufficient to meet the demand of the Chinese people who for ages have appreciated seaweeds and their products for food. Therefore, large quantities of seaweeds and seaweed products had to be imported from various countries, for instance, Eucheuma and Gracilaria from Indonesia and other southeastern Asian countries, Laminaria and agar from Japan, even Porphyra from the USA. Annual Laminaria import from Japan generally amounted to over 10 000 tons and in some years approached 20 000–30 000 tons. Some quantities of the glueweed Gloiopeltis and the vermifuge weed Digenea simplex were exported, mainly to Japan.Since the founding of the People's Republic of China in October, 1949, China has exerted efforts to build up a self-supporting seaweed industry. Now after a lapse of 30-some years, a sizable seaweed industry has been developed. China is now able to produce by phycoculture more than one million tons of fresh seaweeds, including Laminaria, Undaria, Porphyra, Eucheuma, Gracilaria etc. and several thousand tons of seaweed extracts, including algin, agar, carrageenan, mannitol and iodine. At present, China still imports some quantities of seaweeds and seaweed products from various countries but is able to produce sufficient quantities to meet the people's need and even to export some quantities of the seaweeds Laminaria, Undaria and Porphyra and the seaweed products algin and mannitol.At the Tenth International Seaweed Symposium, I presented a paper on the Marine Phycoculture of China, in which I emphasized on the methods of cultivation (Tseng 1981b). Therefore I would like to take this opportunity to supplement the last lecture by presenting a paper on the role of phycological research in the development of China's seaweed industry.     

A decade of change in the seaweed hydrocolloids industry

Seaweed hydrocolloid markets continue to grow, but instead of the 3?C5% achieved in the 1980s and 1990s, the growth rate has fallen to 1?C3% per year. This growth has been largely driven by emerging markets in China, Eastern Europe, Brazil, etc. Sales of agar, alginates and carrageenans in the US and Europe are holding up reasonably well in spite of the recession. However, price increases to offset costs in 2008 and 2009 have begun to have a dampening effect on sales, especially in markets where substitution or extension with less expensive ingredients is possible. These higher prices have been driven by higher energy, chemicals and seaweed costs. The higher seaweed costs reflect seaweed shortages, particularly for carrageenan-bearing seaweeds. The Philippines and Indonesia are the dominant producers of the farmed Kappaphycus and Eucheuma species upon which the carrageenan industry depends and both countries are experiencing factors limiting seaweed production. Similar tightening of seaweed supplies are beginning to show up in brown seaweeds used for extracting alginates, and in the red seaweeds for extracting agar. The structure of the industry is also undergoing change. Producers in China are getting stronger, and while they have not yet developed the marketing skills to compete effectively in the developed world markets, they have captured much of their home market. China does not produce the red and brown seaweeds needed for higher end food hydrocolloid production. Stocking their factories with raw material has led to the supply problems. Sales growth continues to suffer from few new product development successes in recent years; although some health care applications are showing some promise, i.e., carrageenan gel capsules and alginate micro-beads.     

Production of protoplasts from Fusarium scirpi by lytic enzymes from Streptomyces tsusimaensis

Summary The ability of serveral strains of Streptomyces to degrade cell walls from Fusarium scirpi was tested by plating them on agar containing a cell wall preparation derived from the fungus. In this assay, S. tsusimaensis was most effective in producing a clear zone of lysis during growth on the opaque medium. This Streptomyce strain was subsequently grown in liquid culture containing cell walls as the sole carbon source and the exoenzymes were isolated from the culture broth. The enzyme preparation produces a clear zone of lysis when filled into wells in the cell wall agar and was used to prepare protoplasts from F. scirpi. The protoplast yield was 1x10⁹ protoplasts/ml of enzyme solution from 35 mg dry weight of Fusarium mycelium. Protoplasts could be regenerated at a frequency of up to 80%.     

Induction of Attachment of the Mussel Perna perna by Natural Products from the Brown Seaweed Stypopodium zonale

Marine invertebrates settle, attach, and/or metamorphose in response to signals from several sources, including seaweeds. In response to the aquaculture challenge of producing constant numbers of juveniles from cultured species, natural inducers have been screened for their ability to improve those processes. However, few chemical inducers of attachment of invertebrates have been identified, and even less of these were secondary metabolites. The goal of this work was to isolate the natural products responsible for induction activity using bioassay-guided fractionation of the organic extract of the brown seaweed Stypopodium zonale and the attachment of juveniles of the common brown mussel, Perna perna, as a model. The meroditerpene epitaondiol, identified by comparison of spectral data with the literature, promoted as much as 4.7 times more mussel attachment compared to controls at the natural concentration found in this alga (0.041% of the crude extract or 0.012% of algal dry weight). This is the first report showing that a seaweed produces terpenoid compounds as cues for invertebrate attachment, and future studies evaluating this action on settlement of mussels in the field are expected to improve aquaculture technology by increasing mussel spat production.     

High rhenium enrichment in brown algae: a biological sink of rhenium in the sea?

Twenty-one species of seaweed from the California coast were analyzed for rhenium. For the first time, high enrichment (thousandfolds) of rhenium relative to seawater was found in brown algae, but not in green or red algae. Brown algae was suggested as a biological sink of rhenium in the sea and the analogous behavior of technetium to rhenium was found in marine algae. Preliminary incubation experiments with a common brown alga (Pelvetia fastigiata) showed that algal surface is not a major accumulating locus of rhenium.     

A Stachybotrys chartarum isolate from soybean

As part of our effort to investigate fungi associated with soybean roots, Stachybotrys chartarum was isolated from soybean root lesions. Since this fungus has not been reported to cause a disease of soybean, the objectives were to identify and characterize this fungus using biological, chemical, and molecular approaches. Fungal morphology was examined using light and environmental scanning electron microscopy. Phialides bearing conidia arose from determinate, macronematous, dark olivaceous conidiophores. The phialides were obovate or ellipsoidal in whorls. Conidia were unicellular, round or ellipsoidal, 5–13 × 4–7 μm, initially hyaline with smooth walls then dark brown to black and rough-walled when mature. Radial growth of the fungus on cornmeal, oatmeal and potato dextrose agar was 38, 47, and 33 mm in diam., respectively, after 10 days at 25 °C. Pathogenicity was performed using sorghum grain colonized by S. chartarum placed below sown soybean seeds in a soil : sand (1 : 1) steam-pasteurized mix. Three weeks after inoculation, root lesions ranged from 7 to 25 mm long. The fungus was reisolated from soybean root lesions and was reidentified as S. chartarum. Biochemical analysis indicated that this soybean isolate produced satratoxins G and H along with roridin L-2, as well as the spircyclic lactones and lactams in rice culture. PCR using a S. chartarum-specific primer StacR3 and IT51 amplified a 198-bp DNA fragment from the total genomic DNA. The DNA sequence of the ITS region was 100% identical to the S. chartarum strain ATCC 9182, one nucleotide mismatch with S. chartarum strain UAMH 7900, and differed from all published sequences of 12 other species of Stachybotrys and 2 species of Memnoniella in GenBank with genetic divergence ranging from 5.26 to 9.98%. This molecular evidence further supports the identification of S. chartarum isolated from soybean root lesions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Biochemical characteristics of cellulose and a green alga degradation by Gilvimarinus japonicas 12-2T,and its application potential for seaweed saccharification

ABSTRACT

Cellulose is one of the major constituents of seaweeds, but reports of mechanisms in microbial seaweed degradation in marine environment are limited, in contrast to the multitude of reports for lignocellulose degradation in terrestrial environment. We studied the biochemical characteristics for marine cellulolytic bacterium Gilvimarinus japonicas 12-2^T in seaweed degradation. The bacterial strain was found to degrade green and red algae, but not brown algae. It was shown that the bacterial strain employs various polysaccharide hydrolases (endocellulase, agarase, carrageenanase, xylanase, and laminarinase) to degrade seaweed polysaccharides. Electrophoretic analysis and peptide sequencing showed that the major protein bands on the electrophoresis gel were homologous to known glucanases and glycoside hydrolases. A seaweed hydrolysate harvested from the bacterial culture was found useful as a substrate for yeasts to produce ethanol. These findings will provide insights into possible seaweed decomposition mechanisms of Gilvimarinus, and its biotechnological potential for ethanol production from inedible seaweeds.     

Isolation and Pathogenicity of Rhizosphere Fungi of Cocoyam in Relation to Cocoyam Root Rot Disease

Cocoyam is the second most important staple crop of Cameroon and root rot is a destructive disease of this plant. Pythium myriotylum (Pm), Fusarium solani (Fs), and Rhizoctonia solani (Rs) were isolated from the rhizosphere of root rot affected cocoyams and from the soil of a cocoyam experimental field plot temporarily devoid of same in Mamu, Cameroon. Pm was isolated from the above soil by the cocoyam leaf disc baits. Fs and Rs were also isolated from the same soils by the water dilution method and from the roots of diseased cocoyams but were always associated with mycelial growth of Pm. Pathogenicity of Pm and in combinations with Fs or Rs or Fs + Rs all developed cocoyam root rot disease (CRRD) symptoms on 3– and 7–month old cocoyam plantlets 2–7 days after inoculation. Symptoms included rotted roots and wilting with general chlorosis of inoculated plantlets. No symptoms of CRRD were noted on cocoyam plantlets inoculated with Fs, Rs, Fs + Rs, and distilled water. Results indicated that CRRD is not caused by several pathogens but only by Pm. Pm isolates from the soils and roots of diseased cocoyams and those maintained in the ROTREP laboratory have significantly bigger diameter of mycelial colony growth in 24 h–period at 31 °C on lima bean sucrose agar, V–8 juice sucrose agar, and potato sucrose agar than on potato dextrose agar and 2 % water agar. The cocoyam plantlets were raised axenically from tissue culture of explants in the laboratory.     

我国首例肺微小根毛霉病及其致病菌的分离和培养

本文报告1例肺结核和糖尿病并发由微小根毛霉(Rhizomuror pusillus)所致的肺微小根毛霉病。首次在我国从病人的肺组织活检标本分离出该种真菌。此菌可在几种琼脂培养基20°—45℃条件下生长,最适温度为37℃。菌落在初期白色,然后变成褐色厚毡状。在光学显微镜下可看到孢囊梗假轴状分枝,初期无色,然后变为褐色。孢子囊直径50—90μm,呈灰色,后变为褐色。孢子囊成熟后囊壁消解。囊轴卵形或梨形,直径45—48μm。在有性期,接合孢子球形,直径43—63μm,初呈褐色,后变为黑色,表面粗糙或凹凸不平。在透射电子显微镜下,孢囊孢子呈不规则卵形,直径2—5μm;在扫描电子显微镜下,孢囊孢子形态与上述相同。本菌实验感染家兔、豚鼠和小白鼠显示毒力很强,动物于接种后3—10天内全部死亡。从感染动物的脏器分离出本菌。采用中、西医结合治疗,病人痊愈。