scholarly journals Physiological effects of hydrocarbons on phytoplankton

1978 ◽  
Author(s):  
Μιχαήλ Καρύδης
Keyword(s):  
Gas Chromatography ◽  
Individual Species ◽  
Physiological Effects ◽  
Marine Diatoms ◽  
Laboratory Cultures ◽  
Oil Concentration ◽  
Ecological Importance ◽  
The Individual ◽  
Photosynthetic Activities ◽  
Paraffin Fraction

The effect of hydrocarbons on phytoplankton has been studied using laboratory cultures of marine diatoms and flagellates. Low oil concentrations ,stimulate photosynthetic activities while high oil concentration« cause inhibition. The concentrations required for both stimulation and toxicity depend on the individual species. The toxic effects become more obvious after a few days due perhaps to the slow penetration of the oils. The toxicity levels are also affected by the presence of organic material in the medium.. Studies on the ultrastructure hasrshown an effect of the paraffin fraction on the cell wall although the external morphology was not affected. Assimilation of hydrocarbons by the diatoms has also been proved by using gas chromatography. The competition between two species in the presence and absence of oil has been studied to obtain an idea of the ecological importance of this form of pollution.

Effect of UV-B Radiation on Biomass Production, Pigmentation and Protein Content of Marine Diatoms

1984 ◽  
Vol 39 (6) ◽  
pp. 634-638 ◽  
Author(s):  
Günter Döhler
Keyword(s):  
Biomass Production ◽  
White Light ◽  
Primary Productivity ◽  
Exponential Growth ◽  
Marked Decrease ◽  
Dry Weight ◽  
Individual Species ◽  
Marine Diatoms ◽  
Low Levels ◽  
The Individual

Several species of marine diatoms were grown at + 18 °C and + 22 °C under normal air condi­tions (0.035 vol.% C02) at a light/dark alteration of 14: 8̄ h. Intensity of white light was 1 mW (~ 5000 lux). An artifical nutrient solution of 35%o salinity was used. Algae - harvested during exponential growth - were exposed to different intensities of UV-B radiation (439, 717 and 1230 J · m-2 · m-1) for 2 days. UV-B radiation depressed the growth of all tested marine diatoms. Low levels of UV-B resulted in a slight increase of the biomass production (dry weight) compared to not UV-B treated cells. Enhanced UV-B doses caused a diminution of the primary productivity in all species. Algae exposed to UV-B stress showed a marked decrease in the protein and pigment content (chlorophyll a, chlorophyll c1 + c2 and carotenoids). In + 22°C grown cells of Lauderia annulata and Thalassiosira rotula were more sensitive to UV-B radiation than those cultures grown at + 18 °C. Bellerochea yucatanensis cells grown at +22 °C were less affected after UV-B exposure than at +18°C grown algae. The UV-B sensibility and growth of the individual species varied in a mixture of several marine diatoms. Results were discussed with reference to the UV-B effect on metabolic processes.

scholarly journals Gene Sequencing and Phylogenetic Analysis: Powerful Tools for an Improved Diagnosis of Fish Mycobacteriosis Caused by Mycobacterium fortuitum Group Members

2021 ◽  
Vol 9 (4) ◽  
pp. 797
Author(s):  
Davide Mugetti ◽  
Mattia Tomasoni ◽  
Paolo Pastorino ◽  
Giuseppe Esposito ◽  
Vasco Menconi ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Sequencing ◽  
Diagnostic Techniques ◽  
Individual Species ◽  
Identification System ◽  
Mycobacterium Fortuitum ◽  
Biochemical Tests ◽  
Species Determination ◽  
Gene Encoding ◽  
The Individual

The Mycobacterium fortuitum group (MFG) consists of about 15 species of fast-growing nontuberculous mycobacteria (NTM). These globally distributed microorganisms can cause diseases in humans and animals, especially fish. The increase in the number of species belonging to MFG and the diagnostic techniques panel do not allow to clarify their real clinical significance. In this study, biomolecular techniques were adopted for species determination of 130 isolates derived from fish initially identified through biochemical tests as NTM belonging to MFG. Specifically, gene sequencing and phylogenetic analysis were used based on a fragment of the gene encoding the 65 KDa heat shock protein (hsp65). The analyzes made it possible to confirm that all the isolates belong to MFG, allowing to identify the strains at species level. Phylogenetic analysis substantially confirmed what was obtained by gene sequencing, except for six strains; this is probably due to the sequences present in NCBI database. Although the methodology used cannot represent a univocal identification system, this study has allowed us to evaluate its effectiveness as regards the species of MFG. Future studies will be necessary to apply these methods with other gene fragments and to clarify the real pathogenic significance of the individual species of this group of microorganisms.

Taxonomic application of macro and micro morphological characters of seeds in Astragalus L. (Galegeae, Fabaceae) in India

Phytotaxa ◽  
2021 ◽  
Vol 502 (2) ◽  
pp. 191-207
Author(s):  
SHIVANI KASHYAP ◽  
CHANDAN KUMAR SAHU ◽  
ROHIT KUMAR VERMA ◽  
LAL BABU CHAUDHARY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Seed Coat ◽  
Morphological Plasticity ◽  
Morphological Characters ◽  
Individual Species ◽  
Large Size ◽  
The Individual ◽  
Scanning Electron

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.

Larval and post-larval stages of fishes recorded from the plankton of Galway Bay, 1972–73

1976 ◽  
Vol 56 (1) ◽  
pp. 197-211 ◽  
Author(s):  
Julie M. Fives ◽  
F. I. O'Brien
Keyword(s):  
Copepod Species ◽  
Individual Species ◽  
Larval Stages ◽  
Percentage Occurrence ◽  
Bay Area ◽  
The Individual ◽  
Recorded Occurrence

The Galway Bay area was sampled quantitatively for plankton during 1972–3. The larvae and/or post-larvae of 67 species of fish were identified from the plankton. The recorded occurrence per m3 and the percentage occurrence of the individual species is presented and discussed, and reference is made to the concurrent occurrence of various chaetognath species and copepod species. The results of previous investigations of the plankton of the Galway Bay area are mentioned.

scholarly journals Species interactions in three Lemnaceae species growing along a gradient of zinc pollution

2021 ◽  
Author(s):  
Lorena Lanthemann ◽  
Sofia van Moorsel
Keyword(s):  
Growth Rates ◽  
Species Interactions ◽  
Metal Removal ◽  
Lemna Minor ◽  
Polluted Water ◽  
Future Research ◽  
Individual Species ◽  
High Tolerance ◽  
Species Mixture ◽  
The Individual

Duckweeds (Lemnaceae) are increasingly studied for their potential for phytoremediation of heavy-metal polluted water bodies. A prerequisite for metal removal, however, is the tolerance of the organism to the pollutant, e.g., the metal zinc (Zn). Duckweeds have been shown to differ in their tolerances to Zn, however, despite them most commonly co-occurring with other species, there is a lack of research concerning the effect of species interactions on Zn tolerance. Here we tested whether the presence of a second species influenced the growth rate of the three duckweed species Lemna minor, Lemna gibba, and Lemna turionifera. We used four different Zn concentrations in a replicated microcosm experiment under sterile conditions, either growing the species in isolation or in a 2-species mixture. The response to Zn differed between species, but all three species showed a high tolerance to Zn, with low levels of Zn even increasing the growth rates. The growth rates of the individual species were influenced by the identity of the competing species, but this was independent of the Zn concentration. Our results suggest that species interactions should be considered in future research with duckweeds and that several duckweed species have high tolerance to metal pollution, making them candidates for phytoremediation efforts.

scholarly journals Estimation of above-ground phytomass and carbon in tree resources outside the forest (TROF): A geo-spatial approach

2015 ◽  
Vol 24 (1) ◽  
pp. 34-40 ◽  
Author(s):  
B. P. Heyojoo ◽  
S. Nandy
Keyword(s):  
Satellite Image ◽  
Uttar Pradesh ◽  
Individual Species ◽  
Individual Tree ◽  
Spatial Approach ◽  
Specific Standard ◽  
Vegetation Carbon ◽  
Carbon Project ◽  
The Individual ◽  
Species Specific

This study aims to estimate above-ground phytomass and carbon of TROF ecosystem in part of Bijnor district in Uttar Pradesh state of India using IRS P6 LISS-IV satellite image by geo-spatial approach coupled with field sampling. Chacko’s formula was referred to compute number of samples in each TROF types and the sample plot size in each stratum was adopted from Vegetation Carbon Project (VCP) under National Carbon Project (NCP). With the help of field data consisting mainly the height and girth information, volume of each individual tree per plot was obtained using site and tree species-specific standard volumetric equations. The phytomass was calculated by multiplying volume with Biomass Expansion Factor (BEF) then with regional specific gravity of the individual species and summed up in each plot to get total phytomass per plot. The total phytomass per plot was reported to be maximum 544.00 t/ha for linear TROF followed by 121.89 t/ha for block TROF. The carbon from phytomass was obtained by multiplying the total phytomass by a conversion factor that represents the average carbon content in phytomass. Spectral modeling for phytomass with different bands and indices were established and the best fit curve (R2 = 0.552) with red band was applied to generate phytomass and carbon distribution map of the study area.Banko Janakari, Vol. 24, No. 1, pp. 34-40

scholarly journals Random Mutagenesis of Filamentous Fungi Strains for High-Yield Production of Secondary Metabolites: The Role of Polyamines

2020 ◽  
Author(s):  
Alexander A. Zhgun
Keyword(s):  
Filamentous Fungi ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Main Tool ◽  
High Yield ◽  
Individual Species ◽  
Airborne Spores ◽  
Yield Production ◽  
Improvement Programs ◽  
The Individual

A filamentous fungus (also called molds or moldy fungus) is a taxonomically diverse organism from phylum Zygomycota and Ascomycota with filamentous hyphae and has the ability to produce airborne spores or conidia. Currently, more than 70,000 molds are known, and some of them contain unique and unusual biochemical pathways. A number of products from such pathways, especially, the secondary metabolite (SM) pathways are used as important pharmaceuticals, including antibiotics, statins, and immunodepresants. Under different conditions, the individual species can produce more than 100 SM. The strain improvement programs lead to high yielding in target SM and significant reduction of spin-off products. The main tool for the strain improvement of filamentous fungi is random mutagenesis and screening. The majority of industrial overproducing SM strains were developed with the help of such technique over the past 50–70 years; the yield of the target SM increased by 100- to 1000-fold or more. Moreover, most of the strains have reached their technological limit of improvement. A new round of mutagenesis has not increased overproduction. Recently, it was shown that that the addition of exogenous polyamines may increase the production of such improved strains of filamentous fungi. The possible molecular mechanism of this phenomenon and its biotechnological applications are discussed.

scholarly journals EVIDENCE OF MASS MORTALITY OF THE LONG-LIVED BIVALVE MERCENARIA STIMPSONI CAUSED BY A CATASTROPHIC TSUNAMI

Radiocarbon ◽  
2021 ◽  
pp. 1-16
Author(s):  
Kaoru Kubota ◽  
Kotaro Shirai ◽  
Naoko Murakami-Sugihara ◽  
Koji Seike ◽  
Masayo Minami ◽  
...  
Keyword(s):  
Mass Mortality ◽  
Individual Species ◽  
Benthic Organisms ◽  
Nuclear Bomb ◽  
Growth Increments ◽  
Sea Bottom ◽  
Northeastern Japan ◽  
Dating Method ◽  
Ecological Importance ◽  
Benthic Ecosystems

ABSTRACT Tsunamis are huge disasters that can significantly damage benthic organisms and the sea-bottom environment in coastal areas. It is of great ecological importance to understand how benthic ecosystems respond to such destructive forces and how individual species are affected. Investigating the effect of such disasters on animals that are seldom caught alive is particularly difficult. Bivalve mollusks are especially suitable for investigating how a tsunami affects coastal benthic species because they preserve an environmental record in their shells that can be extended back in time by crossdating the records of multiple individuals. Here we studied dead shells of Mercenaria stimpsoni, a long-lived clam, and precisely determined the time of death by using nuclear bomb–induced radiocarbon (bomb-14C) and by counting annual growth increments. First, a quasi-continuous, regional bomb-14C record was created by analyzing the shells of 6 live-caught M. stimpsoni individuals. Then 27 dead shells collected from the seafloor of Funakoshi Bay were 14C-dated and analyzed. The results showed that the huge tsunami that struck northeastern Japan on 11 March 2011 caused mass mortality of this bivalve in Funakoshi Bay. Nine of the 27 clams died during the March 2011 tsunami, probably by starvation after burial by tsunami deposits or exposure above the seafloor as a result of sediment liquefaction during the earthquake. The dating method used in this study can help us understand how long-lived marine organisms with low population density are affected by huge natural disasters such as a tsunami.

scholarly journals Thinopyrum intermedium (Host) Barkw. & Dewey - a review, and evaluation of intermediate and pubescent wheatgrass for dryland agriculture in New Zealand

1998 ◽  
pp. 233-241
Author(s):  
B.J. Wills ◽  
G.B. Douglas ◽  
J. Mckenzie ◽  
K.D. Trainor ◽  
A.G. Foote
Keyword(s):  
New Zealand ◽  
Ground Cover ◽  
Climatic Conditions ◽  
Individual Species ◽  
Thinopyrum Intermedium ◽  
Dryland Agriculture ◽  
Alternative Species ◽  
The Individual ◽  
Local Use

Intermediate and pubescent wheatgrasses (Thinopyrum intermedium) are potentially useful as dryland forage grasses in New Zealand. The recent literature on their international and local use in pasture and cropping situations is reviewed. Under semi-arid conditions at Bendigo Station over a 13-year period, cv. Luna wheatgrass has spread several metres from the original drill lines and it provides very high ground cover. In terms of dryland soil resource conservation this contrasts with adjacent cocksfoot and, to a lesser extent, lucerne plots which have wide-spaced plants interspersed with litter and much bare ground. In a mixed drilling containing wheatgrass, hairy dorycnium, birdsfoot trefoil and sheep's burnet, the first two species now dominate. At Takapau, central Hawke's Bay, annual yields from intermediate and pubescent wheatgrasses produced over 80% of the yield of 10 New Zealand cultivars in spring, summer and autumn, and 65% in the winter. Of the wheatgrasses, cv. Topar intermediate wheatgrass and a pubescent wheatgrass (unnamed line) were the lowest yielding, whereas cv. Oahe and cv. Mandan produced the highest yields. Cv. Greenleaf pubescent wheatgrass had higher foliar nitrogen content than all other species, but in vitro organic matter digestibility was less than 700 g OM/kg DM. Although the wheatgrasses had satisfactory herbage yield and nutritional value, better alternative species are available for pastoral farming in central Hawke's Bay. On Belfield in the Hakataramea Valley, cv. Rush has been the most vigorous wheatgrass for establishment and it seems to handle cold winds and frost well. Hay made from a wheatgrass/ lucerne mix is considered better than that from the individual species as this can increase production by 40-50%, depending on soil and climatic conditions. Usually only one cut per year is taken from the mixed pasture. Crop maintenance includes the application of 200 kg/ha of sulphur super extra every 3-4 years and the pH is maintained at about 5.9-6.4 by liming. A significant advantage is that no stock health, pest or plant disease problems have been noted as yet with any of the wheatgrass varieties available in New Zealand. Keywords: dryland agriculture, New Zealand, Thinopyrum, wheatgrass

scholarly journals Habitat-preference in South African antelope species and its significance in natural and artificial distribution patterns

Koedoe ◽  
1974 ◽  
Vol 17 (1) ◽  
Author(s):  
U. De V. Pienaar
Keyword(s):  
South African ◽  
Habitat Preference ◽  
Distribution Patterns ◽  
Individual Species ◽  
Habitat Requirements ◽  
Unequal Distribution ◽  
Vegetation Zones ◽  
Herbivorous Mammals ◽  
The Individual ◽  
Artificial Introduction

The unequal distribution of species is due to different environmental conditions of the various regions of the globe. The environmental factors governing the occurrence, distribution and abundance of large herbivorous mammals may be divided into physical, historical and biotic. Vegetation is all-important in herbivore biology as it provides habitat, cover and food. Many of the distribution patterns and structural attributes of species are associated with living in and utilizing particular vegetation zones. Africa has an enormous diversity of habitats and animal species utilizing these habitats. An attempt is made to characterize the patterns of habitat preference of South African antelope species and the significance of the habitat requirements of the individual species is discussed in thelight of natural and artificial distribution patterns. It is stressed that artificial introduction of species without prior knowledge of the habitat requirements of such species may lead to disastrous consequences.

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