On a fresh water Hildenbrandia Nardo. from India

The present communication deals with morphological features of a fresh water species of the genus Hildenbrandia Nardo (H. ramanaginaii sp. nov.), new to science.     

Ciliates from Antarctic sea ice

Five ciliates, Chlamydonella prostomata nov. sp., Paractedoctema acruosa nov. gen., nov. sp., Urocyclon ovatum nov. gen., nov. sp., Porpostoma grassei (Corliss and Snyder 1986) and Cytharoides balechi Tuffrau 1974, collected from sea ice in the Weddell Sea, Antarctica were morphologically and taxonomically investigated. The new genus Paractedoctema is characterized as: Cyclidiidae with naked snout-like apical end and three well-developed membranelles which are multi-rowed in structure and closely apposed one to another; paroral membrane extending anteriorly to about mid-level of M1; one caudal cilium; and silverline system Cyclidium-like. Since Urocyclon Small and Lynn 1985 is a nomen nudum because no type species has been fixed, we re-establish the genus and give a revised definition: uronematids mostly with inverted pear-shaped body and subequatorially positioned cytostome; apical plate dominant; membranelle 1 highly reduced; and paroral membrane extending anteriorly to about mid-level of membrane 2. Based on this new definition, a new combination is suggested: Homalogastra cymruensis (Pérez-Uz and Hope 1997) comb. nov. (formerly Urocyclon cymruensis Pérez-Uz and Hope 1997). For the well-known genus Chlamydonella, an improved diagnosis has been given according to our observations and the data obtained: Lynchellidae without plasmatic protrusions on ventral side; several to many somatic kineties making no noticeable naked gap between left and right areas; perioral kineties continuous or slightly fragmented with leftmost rows parallel to each other, which are arched transversely; and cytopharyngeal rods (nematodesmata) toothed. Macronucleus usually dimorphic. Regarding the related genus Lynchella Kahl 1933, we suggest that the original diagnosis by Kahl should be maintained. Thus, the genus diagnosis is re-provided: Lynchellidae with plasmatic protrusions on ventral side; several to many somatic kineties making no noticeable naked gap between left and right areas; perioral kineties continuous or fragmented with some rows parallel to each other; cytopharyngeal rods toothed; macronucleus generally dimorphic. In the light of the redefinition, a new combination has been made: Chlamydonella nordica (Jankowski 1968) comb. nov. (formerly Lynchella nordica Jankowski 1968). Accepted: 10 October 1999     

On two fresh water red algae from Dehradun

Summary The present communication deals with morphological features of a new fresh water species of the genus Acrochaetium Naëg. (A. sarmaii sp. nov.). The occurrence of Compsopogon iyengarii is also recorded for the first time from a locality in North India.     

大型纤毛虫总RNA的提取方法

以冠突伪尾柱虫为材料,建立了一种适合于富含RNase和多糖的大型纤毛虫总RNA的提取方法。该方法采用异硫氰酸弧和β-巯基乙醇联合快速变性,酚、氯仿和异戊醇抽提,同时在变性剂存在的条件下两次选择性地沉淀RNA,从而有效地去除了DNA、蛋白质和多糖。所得RNA样品经电泳、紫外分光光度法检测和RT-PCR分析,证实为完整、均一且无基因组污染的总RNA.这为构建冠突伪尾柱虫有小核系与无小核系之间的削减文库、筛选两细胞系差异表达的基因奠定了基础。     

Gastrotrichs from interstitial fresh water,with a description of four new species

A study was performed on freshwater gastrotrichs living in the interstitial habitat of some lakes in Latium and of Lake Garda (Italy). Thirty-two chetonotids were collected, twenty-five of which could be identified. Four are new to science (Chaetonotus (Hystricochaetonotus) benacensis, Heterolepidoderma lamellatum, Ichthydium plicatum, I. squamigerum), and two are new to the Italian fauna (Heterolepidoderma macrops, H. majus). The faunistic composition of the lakes is compared with previous data. Interstitial gastrotrichs are less varied and abundant than those of epibenthos and periphyton, but often are of taxonomical and zoogeographical interest. The presence in the interstitial of some epibenthic and periphytic species demonstrates their capacity to colonize ecologically different habitats. The grain size of the substrate was not clearly correlated with faunal richness, but there was a possible influence of the amount of the organic detritus in the sediment. Morphological analysis showed a prevalence of small sized animals, with poorly ornamentated cuticular covering and well developed locomotory ciliature, as probable adaptations to interstitial life.     

Pedobacter aquae sp. nov., a multi-drug resistant bacterium isolated from fresh water

A novel bacterial strain designated CJ43^T was isolated from fresh water located in Gangwon-do, South Korea, displaying multi-drug resistance. The isolate was Gram-stain-negative, aerobic, orange-pigmented, and rod-shaped. Strain CJ43^T grew optimally at 30 °C and pH 7 on R2A agar in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain CJ43^T belonged to the genus Pedobacter in the family Sphingobacteriaceae and was most closely related to Pedobacter puniceum HX-22-1 ^T and P. glucosidilyticus 1-2 ^T (98.3 and 98.1% sequence similarity). The genome size of strain CJ43^T was 3.9 Mb in a single contig with DNA G?+?C content of 34.9%. The genome included 3144 predicted protein-coding genes, as well as 55 tRNA, 9 rRNA and 3 ncRNA genes. The genome also contained 128 putative antibiotic resistance genes, reflecting its phenotypes. The average nucleotide identity values between strain CJ43^T and two closely related strains P. puniceum HX-22-1 ^T and P. glucosidilyticus 1-2 ^T were 91.0 and 88.7%, respectively. In silico digital DNA-DNA hybridization results between strain CJ43^T and the related strains were 42.8 and 38.6%, respectively. The major fatty acids of strain CJ43^T were iso-C_15:0, iso-C_17:0 3-OH, and summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c). Strain CJ43^T contained phosphatidylethanolamine as the major polar lipid and menaquinone-7 as the sole respiratory quinone. Based on the polyphasic taxonomy data, strain CJ43^T represents a novel species of the genus Pedobacter, for which the name Pedobacter aquae sp. nov. is proposed with the type strain CJ43^T (=?KACC 21350 ^T?=?JCM 33709 ^T).

     

A survey for viruses from fresh water that infect a eucaryotic chlorella-like green alga

Viruses which formed plaques on lawns of a eucaryotic, chlorella-like green alga were detected in 37% of the 35 freshwater samples surveyed. Virus populations, monitored in seven locations, fluctuated both qualitatively and quantitatively over an 8-month period.     

Roseomonas sediminicola sp. nov., isolated from fresh water

A Gram-stain negative, strictly aerobic, non-motile, non-spore-forming, and rod-shaped bacterial strain designated FW-3^T was isolated from fresh water and its taxonomic position was investigated by using a polyphasic approach. Strain FW-3^T was found to grow at 10–37 °C and at pH 7.0 in the absence of NaCl on nutrient agar. On the basis of 16S rRNA gene sequence similarity, strain FW-3^T was shown to belong to the family Acetobacteraceae and to be related to Roseomonas lacus TH-G33^T (97.2 % sequence similarity) and Roseomonas terrae DS-48^T (96.4 %). The G+C content of the genomic DNA was determined to be 68.0 %. The major menaquinone was determined to be Q-10 and the major fatty acids were identified as summed feature 7 (comprising C_18:1 ω9c/ω12t/ω7c as defined by the MIDI system; 55.4 %), and C_18:1 2OH (29.8 %). DNA and chemotaxonomic data supported the affiliation of strain FW-3^T to the genus Roseomonas. Strain FW-3^T could be differentiated genotypically and phenotypically from the recognized species of the genus Roseomonas. The novel isolate therefore represents a novel species, for which the name Roseomonas sediminicola sp. nov. is proposed, with the type strain FW-3^T (=KACC 16616^T = JCM 18210^T).     

Modeling nitrogen cycling in a coastal fresh water sediment

Increased nitrogen (N) loading to coastal marine and freshwater systems is occurring worldwide as a result of human activities. Diagenetic processes in sediments can change the N availability in these systems, by supporting removal through denitrification and burial of organic N (N_org) or by enhancing N recycling. In this study, we use a reactive transport model (RTM) to examine N transformations in a coastal fresh water sediment and quantify N removal rates. We also assess the response of the sediment N cycle to environmental changes that may result from increased salinity which is planned to occur at the site as a result of an estuarine restoration project. Field results show that much of the N_org deposited on the sediment is currently remineralized to ammonium. A rapid removal of nitrate is observed in the sediment pore water, with the resulting nitrate reduction rate estimated to be 130 μmol N cm⁻² yr⁻¹. A model sensitivity study was conducted altering the distribution of nitrate reduction between dissimilatory nitrate reduction to ammonium (DNRA) and denitrification. These results show a 40% decline in sediment N removal as NO ₃ ⁻ reduction shifts from denitrification to DNRA. This decreased N removal leads to a shift in sediment-water exchange flux of dissolved inorganic nitrogen (DIN) from near zero with denitrification to 133 μmol N cm⁻² yr⁻¹ if DNRA is the dominant pathway. The response to salinization includes a short-term release of adsorbed ammonium. Additional changes expected to result from the estuarine restoration include: lower NO ₃ ⁻ concentrations and greater SO ₄ ²⁻ concentrations in the bottom water, decreased nitrification rates, and increased sediment mixing. The effect of these changes on net DIN flux and N removal vary based on the distribution of DNRA versus denitrification, illustrating the need for a better understanding of factors controlling this competition.     

Actinomycete virus in fresh water

An ecological study was made of the freshwater distribution of Actinomycete virus. One component of this, the virus of Actinoplanes, is highly specific and its pattern of occurrence mirrors that of its host. The occurrence of Streptomyces virus is more difficult to explain in ecological terms, but this is attempted. Micromonospora virus was not obtained and the significance of this is discussed. The Actinoplanes virus is characterized at the fine-structure level by a polyhedral-shaped head with a tail bearing a contractile sheath, the latter feature being previously undescribed for actinophage.     

A survey for viruses from fresh water that infect a eucaryotic chlorella-like green alga.

Viruses which formed plaques on lawns of a eucaryotic, chlorella-like green alga were detected in 37% of the 35 freshwater samples surveyed. Virus populations, monitored in seven locations, fluctuated both qualitatively and quantitatively over an 8-month period.     

On edible Lemanea Bory de St Vincent — a fresh water red alga from India

The present communication deals with the morphological features of a fresh water red alga Lemanea mamillosa Kutz. It has been recorded for the first time from India. Its economic value as food material is mentioned.     

Epibiotic Bacteria on Several Ciliates from Marine Sediments

ABSTRACT Bacterial epibionts were observed on the surface of the marine sediment ciliate Geleia fossata. Rod-shaped bacteria, from 2-10 X10³ per ciliate, were universally positioned in ciliated grooves, in apparent spatial association with dikinetids. SEM and TEM examination of the ciliates confirmed that a tight affiliation exists between the epibiotic bacteria and ciliate cortex infrastructures. These observations, as well as the distinct bacterial distribution pattern over ciliate surface, suggest that there is a close epibiont/host physiological integration. Epibiotic bacteria were also observed on the surfaces of other sediment ciliates from the genera Loxophyllum, Tracheloraphis, Geleia, Paraspathidium , and Cyclidium. These findings indicate that the bacterial/protozoa associations are widespread in the marine benthic environment. The potential benefits for both epibionts and their hosts are discussed.     

Screening of bacteria with antiviral activity from fresh water salmonid hatcheries

Bacteria isolated from two salmonid hatcheries were screened for antiviral activity against infectious hematopoietic necrosis virus (IHNV) to ascertain the presence of bacteria with anti-IHNV activity in the aquatic environment. Out of 710 bacterial isolates from the water and sediment samples, 190 strains showed anti-IHNV activities of more than 50% plaque reduction. These antiviral activities were detected predominantly in Pseudomonas, Aeromonas/Vibrio, and coryneforms. In one hatchery, the bacteria with antiviral activities were more prevalent in sediment samples than in water samples. Seventy-seven percent of the isolates with higher antiviral activities (greater than 90% plaque reduction) belonged to Pseudomonas.