A numerical study of the growth and development of Trichodorus christiei

1968 ◽  
Vol 46 (2) ◽  
pp. 109-114 ◽  
Author(s):  
G. W. Bird ◽  
W. F. Mai
Keyword(s):  
Excretory Pore ◽  
Reproductive System ◽  
Growth And Development ◽  
Numerical Study ◽  
Developmental Time ◽  
Morphometric Character ◽  
Time Interval ◽  
Allometric Growth ◽  
Morphometric Characters ◽  
Stylet Length

An analysis of morphometric and allometric characters was used to study the growth and development of Trichodorus christiei Allen, 1957. The magnitude, location, and time of morphometric growth was determined for 14 characters. With the exception of the stylet length, body width, and characters pertaining to the reproductive system, morphometric characters increased in size more in the second and fourth than in the third developmental time interval. An analysis of 45 pairs of characters was used to study the allometric growth of nematodes belonging to four stages of the life cycle. The reproductive system was found to be relatively stable and numerous pairs of characters exhibited significant allometric growth. Because of the lack of significant allometric growth between the pairs of characters used to form the a and c ratios, these ratios are not suitable for taxonomic purposes pertaining to this species. The lack of significant allometric growth between the stylet and esophagus lengths indicated that these characters should not be combined as neck length for use in the b ratio. Because of the variability of the esophagus as a morphometric character, the excretory pore position defined in terms of distance from the lip region is more suitable for Trichodorus spp. than the excretory pore position defined in relation to its distance from the base of the esophagus.

Separation of Globodera rostochiensis and G. pallida (Tylenchida: Heteroderidae) using morphology and morphometrics

Nematology ◽  
2004 ◽  
Vol 6 (2) ◽  
pp. 171-181 ◽  
Author(s):  
Sanja Manduric ◽  
Edda Olsson ◽  
Jan-Eric Englund ◽  
Stig Andersson
Keyword(s):  
Globodera Rostochiensis ◽  
Pcr Analysis ◽  
Morphometric Character ◽  
Species Determination ◽  
Morphometric Characters ◽  
Identification Methods ◽  
Identification Process ◽  
Second Stage ◽  
Break Points ◽  
Stylet Length

AbstractTwo Globodera rostochiensis and two G. pallida populations (pure and mixed) were analysed by identification methods based on morphology/morphometrics. To assess the accuracy of the identification, PCR analysis was performed on the same specimens. The investigation comprised juveniles, cysts and males. Seven of the most commonly used morphological/morphometric characters were examined: stylet length, length of stylet shaft plus knobs and stylet knob shape of second-stage juveniles; number of cuticular ridges between anus and vulval basin, distance between anus and vulval basin and Granek's ratio of cysts; and spicule shape of males. Altogether, 480 specimens were analysed and assessed. There were statistically significant differences between means of the G. rostochiensis and G. pallida populations in most characters and, in part, between populations of the same species. However, no individual morphological-morphometric character proved to be discriminant for species determination as in all cases there was a large overlap. A statistical discriminant analysis showed that with our populations, the values of a commonly used table of characters for separation of the two species had to be adjusted in order to produce the break points. By judging more than one character, the identification process could be considerably improved, suggesting the possibility of designing a computerised expert system.

Bursaphelenchus michalskii sp. n. (Nematoda: Aphelenchoididae), a nematode associate of the large elm bark beetle, Scolytus scolytus Fabr. (Coleoptera: Curculionidae), in Dutch elm disease-affected elm, Ulmus laevis Pall.

Nematology ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 301-318
Author(s):  
Marek Tomalak ◽  
Anna Filipiak
Keyword(s):  
Body Length ◽  
Bark Beetle ◽  
Excretory Pore ◽  
Dutch Elm Disease ◽  
Molecular Profile ◽  
Male Body ◽  
Morphometric Characters ◽  
Scolytus Scolytus ◽  
Elm Bark Beetle ◽  
Ulmus Laevis

Summary Bursaphelenchus michalskii sp. n. is described from the bark of the European white elm, Ulmus laevis. All propagative stages of the nematode were found in larval galleries of the large elm bark beetle, Scolytus scolytus, and in overlapping gallery systems of this species and the small European elm bark beetle, S. multistriatus. Dauer juveniles of the new nematode are transmitted to new breeding trees under elytra of adult S. scolytus. Bursaphelenchus michalskii sp. n. is characterised by the female body length of 953 (838-1108) μm and male body length of 893 (811-971) μm, very slender body (a = 53.9 (46.1-58.5) and 60.9 (52.2-72.0) in female and male, respectively), lateral fields with three incisures (two bands), excretory pore usually located anterior to the median bulb, lack of vulval flap, long post-uterine sac, relatively small spicules 12.3 (10.8-13.3) μm long with no cucullus and with distinct, somewhat thorn-like, dorsally bent or reflexed condylus and a conical or digitate rostrum, and the arrangement of the seven male caudal papillae (i.e., a single precloacal ventromedian papilla (P1), one pair of adcloacal ventrosublateral papillae (P2) at or just anterior to cloacal slit, one ventrosublateral, postcloacal pair (P3) located at ca 60% of the tail length, posterior to cloacal slit, and one pair (P4) of ventrosublateral papillae located near the base of the bursa). The newly described species shares most of the key morphological characters with members of the eremus-group (sensu Braasch et al., 2009). However, B. michalskii sp. n. is unique amongst Bursaphelenchus species by a combination of female tail and spicule shape, excretory pore position, and other morphometric characters. These findings were confirmed by DNA sequencing and phylogenetic analysis of the 18S and 28S rDNA regions and by the unique molecular profile of the ITS region (ITS-RFLP).

scholarly journals Polikromatik, dimorfisme seksual, dan redeskripsi spesies ikan red devil, Amphilophus amarillo [Stauffer & McKaye, 2002] di Waduk Sermo Yogyakarta

2018 ◽  
Vol 18 (1) ◽  
pp. 69
Author(s):  
Sitty Ainsyah Habibie ◽  
Djumanto Djumanto ◽  
Murwantoko Murwantoko
Keyword(s):  
Control Region ◽  
Principal Component ◽  
Gill Tissue ◽  
Morphometric Character ◽  
Fish Sample ◽  
Trophic Polymorphism ◽  
Sex Dimorphism ◽  
Morphometric Characters ◽  
Male And Female ◽  
Fish Group

Red devil has been extensively researched due to extremely high morphometric and chromatophore variations, including the phenomena of polychromatic and trophic polymorphism. The purpose of this study was to identify and observe the phenomenon of sex dimorphism that occurs in polychromatic red devil species which caught in Sermo Reservoir. Fish sample as much as 240 individual was collected from fishermen catch during November 2016-September 2017 by using gill nets, cest nets, and fishing rods. Subsequently, the fish sample was grouped based on color and sex, the namely group of red devil red, red devil black, and red devil reddish black. The morphometric character data of 21 units were measured in each fish sample, whereas the DNA samples were taken from the gill tissue on each species of two individuals. The morphometric character data was analyzed for discriminant distance, while DNA was analyzed by BLAST (Basic Local Allignment Search Tools) from NCBI. The result of the principal component analysis and discriminant function showed the three group of fish can be distinguished by the characters around the head. The T-test of male and female morphometric characters in each fish group showed the phenomenon of sex dimorphism. Canonical and dendrogram diagrams consistently classify the three group of fish as the same species but are segregated by sex so that significantly dimorphism occurs. The mitochondrial sequencing results of the DNA control region show that among the red devil fish group found in the Sermo Reservoir is a species of A. amarillo.AbstrakRed devil telah banyak diteliti karena variasi morfometrik dan kromatofora yang sangat tinggi, termasuk di dalamnya fenomena polikromatisme dan trofik polimorfisme. Penelitian ini bertujuan untuk mengamati polikromatik dan dimor-fisme seksual serta mengidentifikasi spesies red devil di perairan Waduk Sermo Yogyakarta. Contoh ikan sebanyak 240 ekor diambil dari hasil tangkapan nelayan selama bulan November 2016-September 2017 dengan menggunakan jaring insang, jala dan pancing. Selanjutnya contoh ikan dikelompokkan berdasarkan warna dan jenis kelamin, yaitu kelompok red devil merah, red devil hitam, dan red devil merah kehitaman. Data karakter morfometrik sebanyak 21 unit diukur pada setiap contoh ikan, sedangkan contoh DNA diambil dari jaringan insang pada masing-masing kelompok ikan seba-nyak dua ekor. Data karakter morfometrik dianalisis pembedanya, sedangkan DNA dianalisis dengan BLAST (Basic Local Allignment Search Tools) dari NCBI. Hasil analisis komponen utama dan fungsi diskriminan menunjukkan ketiga kelompok ikan dapat dibedakan berdasarkan karakter yang berada di sekitar kepala. Uji t terhadap karakter morfome-trik jantan dan betina pada masing-masing kelompok ikan menunjukkan fenomena dimorfisme seksual. Diagram kanonikal dan dendrogram konsisten mengelompokkan ketiga kelompok ikan tersebut sebagai spesies yang sama, namun terpisah berdasarkan jenis kelamin sehingga sangat nyata terjadi dimorfisme. Hasil sekuensing mitokondria DNA control region menunjukkan seluruh kelompok ikan red devil yang ditemukan di Waduk Sermo merupakan spesies Amphilophus amarillo.

scholarly journals Intra-specific morphological and morphometric variability of Radopholus similis (Cobb, 1893) Thorne, 1949

2018 ◽  
Vol 10 (3) ◽  
pp. 841-846 ◽  
Author(s):  
S. Roy ◽  
K Roy ◽  
S. Sarkar ◽  
A Rathod ◽  
J. Hore
Keyword(s):  
The Body ◽  
Radopholus Similis ◽  
Body Width ◽  
Head Region ◽  
Morphometric Characters ◽  
Lateral Field ◽  
Oesophageal Gland ◽  
Morphometric Features ◽  
Basal Bulb ◽  
Stylet Length

All the root inhabiting migratory endoparasitic nematode populations of Radopholus procured from banana crop of Vellayani, Thiruvananthapuram, Kerala were identified as Radopholus similis. Heat killed females were straight to slightly ventrally curved posteriorly. Female’s head was low, rounded, continuous or slightly setoff with the body contour. Females were 500-660 µm long and were comparatively longer than males. Males had button shaped head set off by a constriction; female with three to five lip annuli, four crenate and areolated lateral incisures, stylet 14-18 µm long with rounded knobs, vulva post-equatorial (58%), sometimes with slight protuberant lips, ovary paired and equally developed, oesophageal gland overlapped the intestine dorsally, tail elongate-conoid with narrowly rounded terminus. The stylet length (µm), width of stylet knob (µm), distance of excretory pore from anterior end (µm), distance from head to basal bulb (µm), lateral field structure, shape of stylet knob, head region, position of phasmid, tail shape with its terminus, morphometric values like m%, o% and v% and a, c and c´ ratios of females were stable (CV<12%) features. There is an existence of intra-specific variability in the morphological and morphometric features of R. similis. The main morphological diversity was observed with P% of male and female, b ratio of female and stylet length, distance of DEGO from stylet base, o% and T% of male. All the root inhabiting migratory endoparasitic nematode populations of Radopholus Thorne, 1949 procured from banana of Vellayani, Thiruvananthapuram, Kerala were identified as Radopholus similis (Cobb, 1893) Thorne, 1949. A high degree of intra-specific morphometric variability was observed with regard to the total body length (µm), body width (µm), stylet length (µm), distance of dosrsal oesophageal gland orifice (DEGO) from stylet base (µm), number of lip annuli, lip height (µm), distance from head to basal bulb (µm), distance of anus from anterior end (µm), tail length (µm), anal body width (µm), distance of phasmid from tail terminus (µm), number of lateral lines, width of lateral field (µm), b ratio and P % among females of R. similis. Morphometric features like m%, o% and v% of females of R. similis showed least variability. These can be considered as the stable morphometric characters for discrimination of females of R. similis. Ratios like ‘a’ and ‘c’ of females of R. similis were found moderately variable. The morphometric feature and of male i.e. distance from head to basal bulb (µm) was found least variable; while number of lip annuli and spicule length (µm) were moderately variable.  

scholarly journals Morphological and genetic evaluation of the thumbprint emperor, Lethrinus harak (Forsskål, 1775) in the Pacific and Indian Oceans

F1000Research ◽  
2021 ◽  
Vol 9 ◽  
pp. 915
Author(s):  
Muhammad Afrisal ◽  
Yukio Iwatsuki ◽  
Andi Iqbal Burhanuddin
Keyword(s):  
Pacific Ocean ◽  
Indian Ocean ◽  
Genetic Distance ◽  
Marine Biology ◽  
Sequence Data ◽  
Statistical Tests ◽  
Accurate Determination ◽  
Morphometric Character ◽  
Morphometric Characters ◽  
The Pacific

Background: The Lethrinidae (emperors) include many important food fish species. Accurate determination of species and stocks is important for fisheries management. The taxonomy of the genus Lethrinus is problematic, for example with regards to the identification of the thumbprint emperor Lethrinus harak. Little research has been done on L. harak diversity in the Pacific and Indian Oceans. This study aimed to evaluate the morphometric and genetic characters of the thumbprint emperor, L. harak (Forsskål, 1775) in the Pacific and Indian Oceans. Methods: This research was conducted in the Marine Biology Laboratory, Faculty of Marine Science and Fisheries, Hasanuddin University, and Division of Fisheries Science, University of Miyazaki. Morphometric character measurements were based on holotype character data, while genetic analysis was performed on cytochrome oxidase subunit I (COI) sequence data. Morphometric data were analysed using principal component analysis (PCA) statistical tests in MINITAB, and genetic data were analysed in MEGA 6. Results: Statistical test results based on morphometric characters revealed groupings largely representative of the Indian and Pacific Oceans. The Seychelles was separated from other Indian Ocean sites and Australian populations were closer to the Pacific than the Indian Ocean group. The genetic distance between the groups was in the low category (0.000 - 0.042). The phylogenetic topology reconstruction accorded well with the morphometric character analysis, with two main L. harak clades representing Indian and Pacific Ocean, and Australia in the Pacific Ocean clade. Conclusions: These results indicate that the morphological character size of L. harak from Makassar and the holotype from Saudi Arabia have changed. Genetic distance and phylogeny reconstruction are closely related to low genetic distance.

scholarly journals Polyphenol-Rich Purple Corn Pericarp Extract Adversely Impacts Herbivore Growth and Development

Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 98 ◽  
Author(s):  
Mandeep Tayal ◽  
Pavel Somavat ◽  
Isabella Rodriguez ◽  
Tina Thomas ◽  
Bradley Christoffersen ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Growth And Development ◽  
Control Diet ◽  
Insect Pest ◽  
Plant Secondary Metabolites ◽  
Mass Gain ◽  
Developmental Time ◽  
Egg Hatching ◽  
Indirect Defenses ◽  
Purple Corn

Plant secondary metabolites such as terpenes, phenolics, glycosides, and alkaloids play various functional roles including pigmentation, foliar and floral volatile synthesis, hormonal regulation, and direct and indirect defenses. Among these, phenolic compounds are commonly found in plants, but vary in the distribution of their specific compounds among plant families. Polyphenols, including anthocyanins and tannins, are widely distributed and have been well documented for their roles- primarily in plant pigmentation and also in plant defenses. However, commercialization of such compounds for use in insect pest management is severely hampered by expensive, inefficient, and time-consuming extraction protocols. Using a recently developed inexpensive and easy extraction method using the byproducts of pigmented (purple) corn processing, we examined whether the crude pericarp extract rich in polyphenols can affect the growth and development of tobacco hornworm (Manduca sexta L.) caterpillars. Our findings show that purple corn pericarp extract negatively affected M. sexta egg hatching and larval mass gain and prolonged developmental time compared to regular yellow corn extract or an artificial control diet. We also found that these effects were more severe during the early stages of caterpillar development. These results conclusively demonstrate that purple corn pericarp, an inexpensive by-product of the corn milling industry, is a valuable product with excellent potential as an insect antifeedant.

scholarly journals New Results on the Motions of Asteroids in Resonances

1992 ◽  
Vol 152 ◽  
pp. 145-152 ◽  
Author(s):  
R. Dvorak
Keyword(s):  
Initial Conditions ◽  
Numerical Study ◽  
Equations Of Motion ◽  
Close Approach ◽  
Integration Time ◽  
Time Interval ◽  
Time Intervals ◽  
3 Dimensional ◽  
Special Cases ◽  
Good Agreement

In this article we present a numerical study of the motion of asteroids in the 2:1 and 3:1 resonance with Jupiter. We integrated the equations of motion of the elliptic restricted 3-body problem for a great number of initial conditions within this 2 resonances for a time interval of 104 periods and for special cases even longer (which corresponds in the the Sun-Jupiter system to time intervals up to 106 years). We present our results in the form of 3-dimensional diagrams (initial a versus initial e, and in the z-axes the highest value of the eccentricity during the whole integration time). In the 3:1 resonance an eccentricity higher than 0.3 can lead to a close approach to Mars and hence to an escape from the resonance. Asteroids in the 2:1 resonance with Jupiter with eccentricities higher than 0.5 suffer from possible close approaches to Jupiter itself and then again this leads in general to an escape from the resonance. In both resonances we found possible regions of escape (chaotic regions), but only for initial eccentricities e > 0.15. The comparison with recent results show quite a good agreement for the structure of the 3:1 resonance. For motions in the 2:1 resonance our numeric results are in contradiction to others: high eccentric orbits are also found which may lead to escapes and consequently to a depletion of this resonant regions.

Clustering of Bursts of Openings in Markov and Semi-Markov Models of Single Channel Gating

1997 ◽  
Vol 29 (01) ◽  
pp. 92-113 ◽  
Author(s):  
Frank Ball ◽  
Sue Davies
Keyword(s):  
Markov Chain ◽  
Ion Channel ◽  
State Space ◽  
Continuous Time ◽  
Markov Models ◽  
Numerical Study ◽  
Channel Gating ◽  
Markov Renewal Process ◽  
Time Interval ◽  
Continuous Time Markov Chain

The gating mechanism of a single ion channel is usually modelled by a continuous-time Markov chain with a finite state space. The state space is partitioned into two classes, termed ‘open’ and ‘closed’, and it is possible to observe only which class the process is in. In many experiments channel openings occur in bursts. This can be modelled by partitioning the closed states further into ‘short-lived’ and ‘long-lived’ closed states, and defining a burst of openings to be a succession of open sojourns separated by closed sojourns that are entirely within the short-lived closed states. There is also evidence that bursts of openings are themselves grouped together into clusters. This clustering of bursts can be described by the ratio of the variance Var (N(t)) to the mean[N(t)] of the number of bursts of openings commencing in (0, t]. In this paper two methods of determining Var (N(t))/[N(t)] and limt→∝Var (N(t))/[N(t)] are developed, the first via an embedded Markov renewal process and the second via an augmented continuous-time Markov chain. The theory is illustrated by a numerical study of a molecular stochastic model of the nicotinic acetylcholine receptor. Extensions to semi-Markov models of ion channel gating and the incorporation of time interval omission are briefly discussed.

Studies on the morphology of Macrolaimus arboreus Truskova & Eroshenko, 1977 (Rhabditida: Chambersiellidae) from Iran

Nematology ◽  
2018 ◽  
Vol 20 (5) ◽  
pp. 441-447 ◽  
Author(s):  
Ebrahim Shokoohi ◽  
Hadi Panahi ◽  
Hendrika Fourie ◽  
Joaquín Abolafia
Keyword(s):  
Body Length ◽  
Excretory Pore ◽  
Reproductive System ◽  
Tail Length ◽  
The Body ◽  
Female Reproductive System ◽  
Female Tail ◽  
Length Measurements

Summary A population of Macrolaimus arboreus was collected from the rhizosphere of pine in Iran. This population of M. arboreus is characterised by the body length, 800-1010 μm in females, lip region with six seta-like papillae directed anteriad, stoma nearly as long as wide (9-11 × 7 μm), with cheilostom slightly longer than gymnostom and cheilorhabdia and gymnorhabdia well-developed, pharyngeal corpus 1.8-2.0 times the isthmus length, with slightly swollen metacorpus, excretory pore located at isthmus level, female reproductive system monodelphic-prodelphic reflexed with short post-vulval uterine sac, female tail conical (57-67 μm, c = 13.7-15.0, c′ = 3.5-3.8), ending in an acute tip which is weakly curved dorsad, and phasmids at 54-60% of tail length. Measurements and illustrations, including SEM, are provided.

Dielectrophoresis velocities response on tapered electrode profile: simulation and experimental

2019 ◽  
Vol 36 (2) ◽  
pp. 45-53
Author(s):  
Muhammad Izzuddin Abd Samad ◽  
Muhamad Ramdzan Buyong ◽  
Shyong Siow Kim ◽  
Burhanuddin Yeop Majlis
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Particle Velocity ◽  
Applied Voltage ◽  
Electric Field Intensity ◽  
Particle Trajectory ◽  
Numerical Study ◽  
Time Interval ◽  
Content Type ◽  
Field Density

Purpose The purpose of this paper is to use a particle velocity measurement technique on a tapered microelectrode device via changes of an applied voltage, which is an enhancement of the electric field density in influencing the dipole moment particles. Polystyrene microbeads (PM) have used to determine the responses of the dielectrophoresis (DEP) voltage based on the particle velocity technique. Design/methodology/approach Analytical modelling was used to simulate the particles’ polarization and their velocity based on the Clausius–Mossotti Factor (CMF) equation. The electric field intensity and DEP forces were simulated through the COMSOL numerical study of the variation of applied voltages such as 5 V p-p, 7 V p-p and 10 V p-p. Experimentally, the particle velocity on a tapered DEP response was quantified via the particle travelling distance over a time interval through a high-speed camera adapted to a high-precision non-contact depth measuring microscope. Findings The result of the particle velocity was found to increase, and the applied voltage has enhanced the particle trajectory on the tapered microelectrode, which confirmed its dependency on the electric field intensity at the top and bottom edges of the electrode. A higher magnitude of particle levitation was recorded with the highest particle velocity of 11.19 ± 4.43 µm/s at 1 MHz on 10 V p-p, compared to the lowest particle velocity with 0.62 ± 0.11 µm/s at 10 kHz on 7 V p-p. Practical implications This research can be applied for high throughout sensitivity and selectivity of particle manipulation in isolating and concentrating biological fluid for biomedical implications. Originality/value The comprehensive manipulation method based on the changes of the electrical potential of the tapered electrode was able to quantify the magnitude of the particle trajectory in accordance with the strong electric field density.

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