A Model for Responses of Vertebral Numbers in Fish to Environmental Influences During Development

1981 ◽  
Vol 38 (3) ◽  
pp. 334-347 ◽  
Author(s):  
C. C. Lindsey ◽  
A. N. Arnason
Keyword(s):  
Environmental Conditions ◽  
Salmo Trutta ◽  
Published Data ◽  
Temperature Sensitive ◽  
Mathematical Form ◽  
Plecoglossus Altivelis ◽  
Temperature Changes ◽  
Fin Ray ◽  
Time Courses ◽  
Almost All

A model is proposed in which the number of vertebrae formed in an embryo is determined by two independent processes each building up with time. The processes may possibly but not necessarily represent growth and differentiation. Final number is fixed by the level that one process has attained when it is suddenly terminated by arrival of the second process at a critical level. Varying the temperature or other environmental conditions during development can differentially affect the time courses of the two processes and hence alter the numerical outcome. The model, termed "atroposic," is shown to encompass a welter of apparently conflicting published data on vertebral responses of many fish species to different constant temperatures or to single or double temperature changes. It suggests how vertebral numbers may respond strongly and in either direction to temperature perturbations, and how the responses may be extralimitary, and how large responses may be produced by quite brief temperature pulses. Concepts of several temperature-sensitive periods and of shock effects are abandoned. The model is shown to be capable of computerized fit to almost all published data on variation in vertebrae, but to only some on variation in fin-ray number. The atroposic model seems to approximate reality, but the present mathematical form may be only a special case of a more general form yet to be developed.Key words: environmental conditions, meristics, models, temperature responses, vertebrae counts, Salmo trutta, Oryzias latipes, Plecoglossus altivelis

Responses of vertebral numbers in rainbow trout to temperature changes during development

1984 ◽  
Vol 62 (3) ◽  
pp. 391-396 ◽  
Author(s):  
C. C. Lindsey ◽  
A. M. Brett ◽  
D. P. Swain ◽  
A. N. Arnason
Keyword(s):  
Rainbow Trout ◽  
Developmental Stages ◽  
Late Results ◽  
Salmo Gairdneri ◽  
Published Data ◽  
Temperature Changes ◽  
Fin Ray ◽  
Two Temperatures ◽  
The One ◽  
Material Evidence

Eggs from one pair of an inbred hatchery strain of Salmo gairdneri were divided into 16 lots, each of which was subjected either to a sustained temperature of 4 or 12 °C, or to a temperature break (one-way transfer between these two temperatures in either direction), or to a temperature pulse (two-way transfer) at various developmental stages. Breaks in either direction produced overcompensation (vertebral counts beyond that produced by sustained rearing at the temperature to which the embryos were transferred) if applied early, or paradoxical reaction (in the unexpected direction) if applied late. Results from the temperature breaks and from the one successful pulse were satisfactorily fitted by one set of parameters computed for a previously described "atroposic" model. This is the first test for any species which combines results both of breaks in two directions and a pulse, all using the same two temperatures and offspring from a single cross; the model therefore gains credence. Contrary to a previous report, rainbow trout do not differ qualitatively in vertebral response from other teleosts; difficulties in fitting of previously published data on the species probably arose from genetic diversity in the experimental material. Evidence is also presented that fin-ray counts are unreliable in fish preserved at fork lengths of under 29 mm, which may account for failure to fit the atroposic model to our or to most other published responses of salmonid fin rays to temperature changes.

scholarly journals Smart Hydrogel Bilayers Prepared by Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1753
Author(s):  
Weixian Huo ◽  
Heng An ◽  
Shuquan Chang ◽  
Shengsheng Yang ◽  
Yin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gamma Radiation ◽  
Antibacterial Properties ◽  
Cross Linking ◽  
Temperature Sensitive ◽  
Temperature Changes ◽  
Smart Hydrogel ◽  
Isopropyl Acrylamide ◽  
Hydrogel Synthesis ◽  
Potential Applications

Environment-responsive hydrogel actuators have attracted tremendous attention due to their intriguing properties. Gamma radiation has been considered as a green cross-linking process for hydrogel synthesis, as toxic cross-linking agents and initiators were not required. In this work, chitosan/agar/P(N-isopropyl acrylamide-co-acrylamide) (CS/agar/P(NIPAM-co-AM)) and CS/agar/Montmorillonite (MMT)/PNIPAM temperature-sensitive hydrogel bilayers were synthesized via gamma radiation at room temperature. The mechanical properties and temperature sensitivity of hydrogels under different agar content and irradiation doses were explored. The enhancement of the mechanical properties of the composite hydrogel can be attributed to the presence of agar and MMT. Due to the different temperature sensitivities provided by the two layers of hydrogel, they can move autonomously and act as a flexible gripper as the temperature changes. Thanks to the antibacterial properties of the hydrogel, their storage time and service life may be improved. The as prepared hydrogel bilayers have potential applications in control devices, soft robots, artificial muscles and other fields.

scholarly journals Susceptibility of the Candida haemulonii Complex to Echinocandins: Focus on Both Planktonic and Biofilm Life Styles and a Literature Review

2020 ◽  
Vol 6 (4) ◽  
pp. 201
Author(s):  
Lívia S. Ramos ◽  
Laura N. Silva ◽  
Marta H. Branquinha ◽  
André L. S. Santos
Keyword(s):  
Literature Review ◽  
Therapeutic Potential ◽  
Multidrug Resistant ◽  
Antifungal Drugs ◽  
Clinical Isolates ◽  
Published Data ◽  
Life Styles ◽  
Fungal Isolates ◽  
Candida Haemulonii ◽  
Almost All

Candida haemulonii complex (C. haemulonii, C. duobushaemulonii and C. haemulonii var. vulnera) is well-known for its resistance profile to different available antifungal drugs. Although echinocandins are the most effective class of antifungal compounds against the C. haemulonii species complex, clinical isolates resistant to caspofungin, micafungin and anidulafungin have already been reported. In this work, we present a literature review regarding the effects of echinocandins on this emergent fungal complex. Published data has revealed that micafungin and anidulafungin were more effective than caspofungin against the species forming the C. haemulonii complex. Subsequently, we investigated the susceptibilities of both planktonic and biofilm forms of 12 Brazilian clinical isolates of the C. haemulonii complex towards caspofungin and micafungin (anidulafungin was unavailable). The planktonic cells of all the fungal isolates were susceptible to both of the test echinocandins. Interestingly, echinocandins caused a significant reduction in the biofilm metabolic activity (viability) of almost all fungal isolates (11/12, 91.7%). Generally, the biofilm biomasses were also affected (reduction range 20–60%) upon exposure to caspofungin and micafungin. This is the first report of the anti-biofilm action of echinocandins against the multidrug-resistant opportunistic pathogens comprising the C. haemulonii complex, and unveils the therapeutic potential of these compounds.

scholarly journals Modelling and mitigating dose to firefighters from inhalation of radionuclides in wildland fire smoke

2015 ◽  
Vol 24 (5) ◽  
pp. 723 ◽  
Author(s):  
Brian J. Viner ◽  
Tim Jannik ◽  
Daniel Stone ◽  
Allan Hepworth ◽  
Luke Naeher ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Wildland Fire ◽  
Radioactive Material ◽  
Fuel Load ◽  
Base Case ◽  
Published Data ◽  
Case Scenario ◽  
Base Case Scenario ◽  
Fuel Loads ◽  
Radiological Dose

Firefighters responding to wildland fires where surface litter and vegetation contain radiological contamination will receive a radiological dose by inhaling resuspended radioactive material in the smoke. This may increase their lifetime risk of contracting certain types of cancer. Using published data, we modelled hypothetical radionuclide emissions, dispersion and dose for 70th and 97th percentile environmental conditions and for average and high fuel loads at the Savannah River Site. We predicted downwind concentration and potential dose to firefighters for radionuclides of interest (137Cs, 238Pu, 90Sr and 210Po). Predicted concentrations exceeded dose guidelines in the base case scenario emissions of 1.0 × 107 Bq ha–1 for 238Pu at 70th percentile environmental conditions and average fuel load levels for both 4- and 14-h shifts. Under 97th percentile environmental conditions and high fuel loads, dose guidelines were exceeded for several reported cases for 90Sr, 238Pu and 210Po. The potential for exceeding dose guidelines was mitigated by including plume rise (>2 m s–1) or moving a small distance from the fire owing to large concentration gradients near the edge of the fire. This approach can quickly estimate potential dose from airborne radionuclides in wildland fire and assist decision-making to reduce firefighter exposure.

Temperature Sensitivity of Intracellular and Extracellular Soil Enzyme Activities

2021 ◽  
Author(s):  
Adetunji Alex Adekanmbi ◽  
Laurence Dale ◽  
Liz Shaw ◽  
Tom Sizmur
Keyword(s):  
Enzyme Activity ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Extracellular Enzymes ◽  
Extracellular Enzyme ◽  
Daily Maximum ◽  
Temperature Sensitive ◽  
Intracellular Enzyme ◽  
Temperature Changes ◽  
Som Decomposition

<p>Predicting the pattern of soil organic matter (SOM) decomposition as a feedback to climate change, via release of CO<sub>2</sub>, is extremely complex and has received much attention. However, investigations often do not differentiate between the extracellular and intracellular processes involved and work is needed to identify their relative temperature sensitivities. Samples were collected from a grassland soil at Sonning, UK with average daily maximum and minimum soil temperature of 15 °C and 5 °C. We measured potential activities of β-glucosidase (BG) and chitinase (NAG) (extracellular enzymes) and glucose-induced CO<sub>2 </sub>respiration (intracellular enzymes) at a range of assay temperatures (5 °C, 15 °C, 26 °C, 37<sup>  </sup>°C, and 45 °C). The temperature coefficient Q<sub>10</sub> (the increase in enzyme activity that occurs after a 10 °C increase in soil temperature) was calculated to assess the temperature sensitivity of intracellular and extracellular enzymes activities. Between 5 °C and 15 °C intracellular and extracellular enzyme activities had equal temperature sensitivity, but between 15 °C and 26°C intracellular enzyme activity was more temperature sensitive than extracellular enzyme activity and between 26 °C and 37 °C extracellular enzyme activity was more temperature sensitive than intracellular enzyme activity. This result implies that extracellular depolymerisation of higher molecular weight organic compounds is more sensitive to temperature changes at higher temperatures (e.g. changes to daily maximum summer temperature) but the intracellular respiration of the generated monomers is more sensitive to temperature changes at moderate temperatures (e.g. changes to daily mean summer temperature). We therefore conclude that the extracellular and intracellular steps of SOM mineralisation are not equally sensitive to changes in soil temperature. The finding is important because we have observed greater increases in average daily minimum temperatures than average daily mean or maximum temperatures due to increased cloud cover and sulphate aerosol emission. Accounting for this asymmetrical global warming may reduce the importance of extracellular depolymerisation and increase the importance of intracellular catalytic activities as the rate limiting step of SOM decomposition.</p>

scholarly journals Distribution and Ecology of Clathrus archeri in Romania

2014 ◽  
Vol 6 (3) ◽  
pp. 288-291
Author(s):  
Cipran BÎRSAN ◽  
Ana COJOCARIU ◽  
Elena CENUŞĂ
Keyword(s):  
Plant Communities ◽  
Environmental Conditions ◽  
Rare Species ◽  
Western Europe ◽  
Habitat Type ◽  
Published Data ◽  
Hay Meadows ◽  
Eastern Carpathians ◽  
Distribution And Ecology

Although Clathrus archeri is a widely spread species in the Western Europe, in Romania it is considered a rare species, identified from only eight sites. In July 2013, it was found in two new sites from Gurghiu and Bârgău Mountains, in the Romanian Eastern Carpathians. This paper presents a detailed description of the new recorded specimens and of the habitat where this fungus was found. Plant communities where Clathrus archeri was recorded belong to the “mountain hay meadows” habitat type (Festuco rubrae - Agrostietum capillaris community). Taking into consideration the previous published data, the comparison with other habitats types in which this species occurs suggests that Clathrus archeri has no special preferences for certain environmental conditions.

Intraspecific variation and structuring of phenotype in a lake-dwelling species are driven by lake size and elevation

2020 ◽  
Vol 131 (3) ◽  
pp. 585-599
Author(s):  
J Peter Koene ◽  
Kathryn R Elmer ◽  
Colin E Adams
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Geographic Area ◽  
Geographic Region ◽  
Shape Variation ◽  
Multivariate Statistical ◽  
Geometric Morphometric ◽  
Medium Scale ◽  
Natural Lakes ◽  
Almost All

Abstract The fragmented, heterogeneous and relatively depauperate ecosystems of recently glaciated lakes present contrasting ecological opportunities for resident fish. Across a species, local adaptation may induce diverse and distinct phenotypic responses to various selection pressures. We tested for intraspecific phenotypic structuring by population in a common native lake-dwelling fish species across a medium-scale geographic region with considerable variation in lake types. We investigated potential lake-characteristic drivers of trophic morphology. Using geometric morphometric techniques, we quantified the head shapes of 759 adult brown trout (Salmo trutta L.) from 28 lakes and reservoirs across Scotland. Multivariate statistical analyses showed that almost all populations differed from one another. Trout from larger and deeper lakes had deeper, but shorter heads, and smaller eyes. Higher elevation lakes were associated with fish with shorter heads and jaws. Within-population shape variation also differed by population, and was positively correlated with lake surface area and depth. Trout within reservoirs differed subtly from those in natural lakes, having larger eyes, shorter jaws and greater variability. This study documents an extraordinary morphological variation between and within populations of brown trout, and demonstrates the role of the extrinsic environment in driving phenotypic structuring over a medium-scale and varied geographic area.

scholarly journals Transposition of Tn125encoding the NDM-1 carbapenemase inAcinetobacter baumannii

2016 ◽  
pp. AAC.01755-16 ◽  
Author(s):  
Séverine Bontron ◽  
Patrice Nordmann ◽  
Laurent Poirel
Keyword(s):  
Acinetobacter Baumannii ◽  
Direct Evidence ◽  
Opportunistic Pathogen ◽  
Target Site ◽  
Gram Negative Bacteria ◽  
Transposition Frequency ◽  
Gram Negative ◽  
Temperature Changes ◽  
Site Consensus ◽  
Almost All

TheblaNDM-1gene encodes a carbapenemase that confers resistance to almost all β-lactams, including latest resort carbapenems. It is increasingly reported worldwide in nosocomial and community-acquired Gram-negative bacteria.Acinetobacter baumanniiis an important opportunistic pathogen considered as an intermediate reservoir for theblaNDM-1gene. In this species, theblaNDM-1gene is located within the Tn125composite transposon. The mechanism driving the mobility of Tn125has not yet been elucidated. Here we experimentally demonstrated transposition of Tn125inA. baumannii. Systematic 3-bp duplication of the target site, being signature of transposition, was evidenced. The target site consensus for Tn125transposition was found to be GC-enriched at the duplicated 3 bp and AT-rich in the vicinity. Transposition frequency was not influenced by temperature changes or by exposure to sub-inhibitory concentrations of various antibiotics. This work is the first direct evidence of the functionality of a composite transposon inA. baumannii. It provides a mechanistic clue for the dissemination of theblaNDM-1gene inAcinetobacterspp. and subsequently among Enterobacteriaceae.

scholarly journals Characteristics, Behavior, and Environmental Conditions Residence of Leptospirosis Patients in the District of Probolinggo

2021 ◽  
Vol 5 (1) ◽  
pp. 15-22
Author(s):  
Fransisca Putri Intan Damalia ◽  
Atik Choirul Hidajah ◽  
Agus Ardiyansyah
Keyword(s):  
Environmental Conditions ◽  
Male Gender ◽  
Narrative Form ◽  
Well Water ◽  
Clean Water ◽  
Healthy Life ◽  
Hands And Feet ◽  
Almost All ◽  
Age Range ◽  
Flood Prone Areas

Leptospirosis is a zoonotic disease caused by Leptospira sp. and carried by rats as the main source of transmission through its urine. Risk factors for the sufferer are the condition and activity of daily individuals. Probolinggo Regency became one of the regencies/cities in East Java that had been infected by Leptospirosis and as of 20 January 2020 the case amounted to 4 and 2 of which died. This research aims to illustrate the characteristics, behaviors, and environmental conditions of the Leptospirosis in Probolinggo Regency. The research was conducted by describing four cases of Leptospirosis found in Probolinggo Regency from 1 – 20 January 2020. The cases found are depicted according to characteristic variables, behaviors, and environmental conditions. Data analysis is done in a descriptive, namely describing the distribution and presentation of each variable. Data is presented in a table or narrative form. The results showed that 75% of the patients of Leptospirosis are male-gender with an age range of 45-59 years old. Work of some sufferer (50%) is a risky job, namely farmers and builders. No sufferers use gloves during contact with puddle, the use of footwear to the yard and the habit of washing hands and feet after the activity is only done by some sufferers (50%). Almost all sufferers (75%) using well water as a source of clean water. 50% of sufferers do not have sewers. Most sufferers (75%) have pets or livestock and be aware of the presence of rats in the house. Bins owned by most sufferers (75%) is a type of open trash can. Half of the number of sufferers residing in flood prone areas. Therefore, it takes a disciplined attitude in the implementation of clean and healthy life during activities to prevent the occurrence of Leptospirosis.

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