Valve Width Research Articles

Description of Two New Species of Stauroneis Ehrenberg (Naviculales, Bacillariophyceae) from the Russian Far East Using an Integrative Approach.

Stauroneis (Naviculales, Bacillariaceae) are widespread, mostly in fresh-water habitats, and account for 343 species. They are described mainly on the basis of morphology and morphometric traits. These characteristics vary during life cycles and may overlap between species, making their identification difficult. We isolated two strains of naviculoid diatoms and examined them using an integrative approach (phylogenetic, morphological, ultrastructural data, and life cycle). Phylogenetic analyses based on chloroplast rbcL gene data showed affinity of the new strains to the genus Stauroneis. Our algae share morphological features typical of Stauroneis but differ from similar species in minimal valve length measurements, valve apex shape, and minimal number of striae in 10 μm. Two strains are distinct from each other in maximal valve length and width, partially valve shape, the number of areolae in 10 μm, and cingulum structure. It was revealed that the strains reproduce via isogamy. Three species delimitation methods (ASAP, PTP, and GMYC) also confirmed that the two closely related new strains represent distinct species. Based on molecular data and phenotypic traits examined within the framework of an integrative approach, we describe two new isolates as Stauroneis urbani sp. nov. and Stauroneis edaphica sp. nov.

Gomphonema beaugerianum, a new Gomphonema species (Bacillariophyta) found in a historic William Smith sample from the Auvergne (France)

A large, unknown Gomphonema taxon belonging to the G. truncatum group was observed in a historic sample collected by William Smith during his 1854 excursion in the Auvergne (France). The unknown species presented sufficient differences with all known taxa in the truncatum-capitatum group to warrant further morphological investigations. Detailed light and scanning electron microscopy investigations in comparison with all published literature revealed that the unknown species had a unique combination of morphological (uniseriate striae, lack of well-develop headpole) and morphometric (large valve width) features. Therefore, the species is described as new: Gomphonema beaugerianum sp. nov. The new species was observed in Lac de Guéry, an oligotrophic, almost circumneutral lake in the Auvergne with a high ecological quality.

Morphometric evaluation of the left atrioventricular valve complex and its clinical relations.

In this study, it was aimed to evaluate morphometrically and morphologically the left fibrous ring, mitral leaflets, tendinous cords, and papillary muscles, which are the components of the left atrioventricular valve complex (LAVC), and to reveal their clinical relationships. A total of 120 human hearts were examined at the Forensic Medicine Institute. Cases aged 30 years and older, less than 24 hours after their death, were included in the study. Heart length, width, height/width ratio, anteroposterior and mediolateral diameters of the annulus, annular area, length and width of leaflets, number and attachment sites of tendinous cords, number, shape, length, the width of papillary muscles, and distances to various points were recorded to determine their spatial configurations. As well as the measurement data of LAVC components in cases with and without cardiovascular disease (CVD), the relationships of these data with the demographic characteristics of the cases are also explained. In the diagnostic performance test (ROC analysis), it was determined that body mass index (> 26.7), heart weight (> 414 g), heart height/width ratio (≤ 1.24), mitral valve width (> 99.96 mm), left ventricular wall thickness (> 15.08 mm), annular area (> 619.37 mm²) and mediolateral diameter of the annulus (> 30.71 mm) are important diagnostic criteria in determining CVD if they are outside the specified reference values. This study provides anatomical information about LAVC, as well as recommendations for diagnosis and surgical treatment planning. We therefore believe that our findings will be useful to clinicians.

О МОРФОЛОГИЧЕСКОЙ ИЗМЕНЧИВОСТИ ДИАТОМОВОЙ ВОДОРОСЛИ KARAYEVIA SUCHLANDTII (BACILLARIOPHYTA)

This scanning electron microscopy study investigates morphological features of the frustule of the diatom algae Karayevia suchlandtii. The study is based on material collected from the Svir River tributaries (Lake Ladoga basin): Ivina, Yanega, Uslanka,Vazhinka, Oyat, Pasha. Quantitative (the valve length and width, the number of striae in 10 µm) and qualitative (the valve shape and the shape of axial areas, the stiae arrangement) characteristics are analyzed. In the surveyed populations of K. suchlandtii, the minimum values of the valve size are smaller than those given in the original description and the literary, that makes it possible to extend the diagnosis of the species.

МОРФОЛОГИЧЕСКАЯ ИЗМЕНЧИВОСТЬ ИНТЕРЕСНЫХ ДЛЯ ФЛОРЫ РОССИИ ВИДОВ РОДА NAVICULA (BACILLARIOPHYTA)

This scanning electron microscopy study was carried out to investigate the morphology of representatives of the diatoms Navicula cryptocephala, N. metareichardtiana and N. upsaliensis from the phytoperiphyton of 6 tributaries of the Svir River (Lake Ladoga basin). Some of the studied quantitative (valve width, number of striae and lineolae in 10 µm) and qualitative (shape of the central area, striae arrangement) characteristics showed a wider variability, which made it possible to refine the diagnoses of these species taking into account the literature data.

Sellaphora jiuzhaienis sp. nov. (Bacillariophyceae)—A new diatom species from Jiuzhaigou National Nature Reserve, China

A new species Sellaphora jiuzhaienis sp. nov. was found in epilithic samples from Jiuzhaigou National Nature Reserve, China. The species is described herein as new to science based on light microscopy (LM) and scanning electron microscopy (SEM), and ecological information is provided. The species has linear to linear-elliptic valves, 17.5–33.5 μm long and 7.0–8.5 μm wide and very broad conopeum that occupies almost half of the valve width. The discovery of a new diatom species confirms the importance of Jiuzhaigou not only in terms of species richness and endemicity but also for the biodiversity of freshwater karst ecosystems in the national protected areas of China.

Three new cymbelloid species in the genera Cymbella, Cymbopleura and Delicatophycus from the mineral spring Crvena Voda near Skopje, Republic of North Macedonia

Mineral springs are unique habitats frequently inhabited by specific diatom species with restricted distributions. In the mineral spring Crvena Voda near Skopje, three cymbelloid taxa were observed, whose morphological characteristics differ from already known taxa. They are described here as: Cymbella parahelvetica sp. nov., Cymbopleura angustilanceolata sp. nov. and Delicatophycus fontinalis sp. nov. Cymbella parahelvetica sp. nov. is characterized by the absence of an apical pore field at the valve ends and by very densely arranged striae. Cymbopleura angustilanceolata sp. nov. can be distinguished from other Cymbopleura species by the valve outline, the shape of the central area and the stria density. Delicatophycus fontinalis sp. nov. can be differentiated from similar species by its strongly arched dorsal margin, its valve width and stria density.

МОРФОЛОГИЯ, ТАКСОНОМИЯ И ЭКОЛОГИЯ NAVICULA PHYLLEPTA (BACILLARIOPHYTA)

This scanning electron microscopical study of algae from lakes in the in vicinity of the Ust-Lena Reserve made it possible to obtain new information on the morphology of a number of representatives of the genus Navicula: N. phyllepta and N. phylleptosoma. A wider variability of the main quantitative (valve length and width, the number of striae and areolae in 10 µm) and qualitative (structure of the raphe) diagnostic features as well as the conspecificity of the two species were shown. It is proposed to reduce N. phylleptosoma to synonymy of N. phyllepta and extend the diagnosis of the latter.

МОРФОЛОГИЯ И ТАКСОНОМИЯ РЕДКОГО ВИДА NUPELA SILVAHERCYNIA (LANGE-BERTALOT) LANGE-BERTALOT (BACILLARIOPHYTA)

This electron microscopy study was undertaken to investigate morphological features of the frustule of the diatom Nupella silvahercynia. Materials from Lake Pizanets (Republic of Karelia) and S.I. Genkal’s iconotheca of scanning electron microscopy images of valves collected from Karelian water bodies and watercourses were used. A comparative analysis of quantitative (valve length and width, number of striae and areolae in 10 µm) and qualitative (shape of valve, central and axial areas, arrangement of raphe and striae) features showed the similarity of this species with N. vitiosa, which made it possible to reduce N. silvahercynia to synonymy of the latter. The new data also allowed us to expand the diagnosis and range of N. vitiosa.

Computational fluid dynamic analysis of corona virus patients breathing in an airplane

Effective ventilation systems are essential to control the transmission of airborne aerosol particles, such as the SARS-CoV-2 virus in aircraft cabins, which is a significant concern for people commuting by airplane. Validated computational fluid dynamic models are frequently and effectively used to investigate air distribution and pollutant transport. In this study, the effectiveness of different ventilation systems with varying outlet vent locations were computationally compared to determine the best ventilation system for minimizing the risk of airborne transmission. The cabin air conditioning system was optimized to determine how design variables (air inlet temperature, outlet valve width and location, and mass flow rate) affect output parameters, including particle residence time, age of air, and thermal comfort conditions. Inlet mass flow rate was observed to be an influential variable impacting all output parameters, especially on age of air, where it was the most influential. In contrast, the least effective variable was width of the outlet valve, which only affected the particle residence time. Also, Predicted Mean Vote and Predicted Percentage Dissatisfied indices were the most affected by air inlet temperature, which had an inverse relation, while the outlet valve location had the greatest effect on particle residence time.

<i>Brevilinea kevei</i> (Bacillariophyta)—a New Genus and Species for the Flora of Russia

This scanning electron microscopy study of phytoplankton from the Nizhny-Tagil Reservoir has revealed a small-sized genus and species of diatoms, Brevilinea kevei, new to the flora of Russia. Small differences from the original description in the minimum values of the valve width and a higher variability range of the number of striae in 10 µm allow the authors to refine the species description. New data on the location make it possible to clarify the ecology and geographical range of Brevilinea kevei.

Design and simulation of non-uniform electric field using mesh electrodes for electrorheological micro valves

The refresh rate of two-dimensional tactile information for visual impaired people using electrorheological (ER) technology is directly related to the flow rate of an ER valve. The bigger the flow rate is, the faster the tactile information is refreshed. For a parallel electrodes ER valve configuration, due to the limitation of Braille standard to the width of ER valve, the gap of flow channel which is also the gap of parallel electrodes is the only adjustable parameter to benefit the flow rate and at same time enhance operating voltages which contribute a big part of costs to a two-dimensional tactile information display system. A new mesh electrodes configuration is introduced to decouple the flow rate from the gap of electrodes while the flow cross section is determined by parameters of mesh electrodes. A quantity of effective electric field strength of an ER interaction space unit is used to evaluate the anisotropy electric field governed by mesh electrodes. The influences of geometrical parameters of mesh electrodes and applied voltages on the effective electric field strength were analyzed by using COMSOL Multiphysics. The simulation results show that the effective electric field strength increases with applied voltages and wire diameters, and decreases with electrodes gap and mesh clearances. These results provide fundamental laws for designing an ER micro valve governed by non-uniform electric field to some ER applications.

Diatomasinensis: a new diatom species (Bacillariophyta) found in the brackish Lake Qinghai, China.

Lake Qinghai is an ancient brackish water lake in which several endemic diatom species have been discovered. In this study, a species of Diatoma is observed under light and scanning electron microscopy and described as new, Diatomasinensis sp. nov. The living cells of D.sinensis always lie in girdle view due to the cell depth being much larger than valve width (3.3-8.8 vs. 2.0-3.0 μm). The valves of D.sinensis are characterized by their narrow, linear-lanceolate outline, with capitate to subcapitate apices, the presence of two rimoportulae, one at each apex, embedded in the last rib or located among striae and a 4:2 configuration of girdle bands in normal vegetative cells, with four bands assigned to the epivalve and two to the hypovalve. The new taxon is compared with similar species from the genera Diatoma and Distrionella.

A new small marine Diploneis species (Diploneidaceae, Bacillariophyta) from Guangdong Province, China

A Diploneis species new to science is described here, collected from an intertidal sandy beach in Guangdong Province, China. The species has morphological features such as small elongated-elliptical valves, a linear longitudinal canal open outside by one row of C-shaped areolae throughout the whole length, a straight and simple raphe, alveoli occluded externally by a vola and internally by a thin hymen, perforations arranged in a hexagonal array that occupy approximately one-fourth to one-sixth of the valve width, and the other part of the alveolate striae covered by a broadly semilune hyaline area at the middle of the valve. Differences with other similar taxa of this genus are discussed.

Three new Achnanthidium (Bacillariophyceae) species from Lake Salda (Anatolia, Turkey), a deep soda lake

Background and aims – Kützing separated the genus Achnanthidium from the genus Achnanthes based on two species: Achnanthes minutissima and Achnanthidium microcephalum. These two genera were distinguished by the presence of stalks in the Achnanthes genus and their absence in Achnanthidium. Before electron microscopy, the difference between Achnanthes and Achnanthidium was not clear, especially in Achnanthidium minustissimum sensu lato. The aim of the study is to describe three new species of Achnanthidium from Lake Salda. Material and methods – Lake Salda is located in southwestern Anatolia, in Turkey. The diatoms were collected seasonally from four stations in the lake between 2016 and 2020, from different substrata (epipelic, epiphytic, and epilithic). Key results – Three new species belonging to the genus Achnanthidium have been found in Lake Salda, Turkey. Based on the morphological observations, all new taxa are part of the Achnanthidium minutissimum complex. Achnanthidium barlasii sp. nov. and A. dumlupinarii sp. nov. show a high degree of similarity to each other, but can be separated based on valve outline and a denser areolation, especially in striae close to the apices of the raphe valve. Both species can be distinguished from A. minutissimum based on more separate apices and less elliptic valves. In the case of A. dumlupinarii sp. nov., large specimens show slight undulations of the valve, which is a unique feature. Achnanthidium anatolicum sp. nov. is the most characteristic based on its valve width, broadly rounded valve apices, and almost straight valves in girdle view. All newly described Achnanthidium species can be found in lentic environments, with alkaline water and high calcium ion content. Conclusion – The newly described taxa occurred in the unique habitat of a soda lake. The environment of the lake is highly alkaline, rich in magnesium and calcium, and derived from limestone and dolomitic limestone rocks.

Морфологічна мінливість деяких видів пенатних діатомових водоростей (Bacillariophyta) із водойм зони відчуження Чорнобильської АЕС (Україна)

This scanning electron microscopy study of the morphology of pennate diatoms (Achnanthidium eutrophilum (Lange-Bertalot) Lange-Bertalot, Aneumastis stroesei Mann et Stickle, Gomphonema italicum Kützing, G. pala Reichardt, G. vibrio Ehrenberg, Punctastriata ovalis Williams et Round) from phytoperiphytic communities in the cooling pond of the Chernobyl nuclear power plant and natural lakes of the Exclusion Zone (Glyboke and Daleke lakes) has revealed a higher variability in quantitative characteristics (valve length and width, number of striae in 10 µm). At the same time, no variability of qualitative features (shape of valve, axial and central area, raphe and striae arrangement) has been observed in these species. In A. eutrophilum, the number of striae in 10 µm differ from the published data, in A. stroesei – the valve length, in G. pala, G. vibrio and P. ovalis – the valve length and width. The range of variation in the number of striae in 10 µm in G. pala and the valve length and the number of striae in 10 µm in A. stroesei and G. italicum disagree with the literature data. The first electron micrographs of the inner surface of the valve and the corresponding data on its morphology are obtained for A. eutrophilum, A. stroesei, G. italicum, G. pala and G. vibrio.

Analysis of the type material of Gomphosphenia tackei (Bacillariophyceae) and comparison to epizoic diatom populations on freshwater snails

Background and aims – Hustedt (1942) originally described Gomphosphenia tackei from Germany under the name Gomphonema tackei. Because of the small cell size and the lack of scanning electron microscopy (SEM) images from the type material, it is often confused with other species from this genus, especially with G. stoermeri. The aim of this paper was to present detailed morphological characteristics of G. tackei based on the analysis of the type material and of several epizoic populations from Central Europe. Material and methods – The material in this study was collected from the shells of the freshwater snails Lymnaea stagnalis, Planorbarius corneus, and Planorbis planorbis. Additionally, for an unambiguous species identification, the type material for Gomphosphenia tackei was analyzed using light and scanning electron microscopes.Key results – The presence of Gomphosphenia tackei was confirmed in the studied material. The largest population (up to 19%) was recorded on the shell surfaces of living snails, whereas on empty shells, the diatom did not seem to be present or only in very low numbers. Valves are typically clavate with rounded apices. Valves are frequently observed in girdle view, often joint together in pairs. The valves in the studied populations had a valve length of 7–29 µm, a valve width of 3–4 µm, and a stria density of 25–29 striae in 10 µm. In the type population, valve length ranged from 7.5 to 27 µm with a valve width of 3.0–4.0 µm and a stria density of 23–29 striae per 10 µm. Striae were composed of 2–4 elongated to rounded areolae per stria. At the apices, the striae were composed of one single areola. The cells were attached to the substratum by their footpole.Conclusion – Published illustrations of Gomphosphenia tackei do not always correctly represent this species. Individual cells are attached to the substratum by secreted mucilage, probably via their areolae or girdle band pores located on the footpole.

Morphology and morphometric variations in Indian populations of Meloidogyne graminicola Golden and Birchfield, 1965

The study aimed at the morphological and morphometrical characterisation of eight populations of Meloidogyne graminicola from India. We studied different life stages, female, second-stage juveniles (J2s) and eggs of each M. graminicola population. Female characters such as stylet length, distance from the head-end to the median bulb, length and width of metacorpus valve were considered as stable characters. The distance between anus to vulval slit, and phasmid to the anus in perineal pattern showed the least variations. Similarly in body length, stylet length, and the ratio of c-value in J2s showed the least variations. This study noted two types of J2s; the short-form in Assam, Karnataka, Odisha, and West Bengal and the long-form in Haryana, Himachal Pradesh, Uttar Pradesh, and Tamil Nadu. They could be easily identified; the short form J2s is 410-480 µm and the long-form is 510-580 µm.

Revision of the Psammothidium manguinii complex (Bacillariophyta) in the sub-Antarctic Region with the description of four new taxa

Psammothidium manguinii is a common constituent of the limnoterrestrial diatom flora of the Antarctic Region. The species shows a broad variability in several morphological and morphometrical features such as valve outline, valve width, striation pattern and length/width ratio. Analysis of the type material of Achnanthes manguinii, described by Hustedt in 1952, and A. manguinii var. elliptica, described by Manguin two years later, together with an analysis of a large number of P. manguinii populations from the sub-Antarctic Region (with samples from all major islands in the southern Atlantic, Indian and Pacific Ocean), resulted in a clear morphological revision of the species. Four new species are described, P. acutomanguinii sp. nov., P. antarcticum sp. nov., P. mannensianum sp. nov. and P. hodgsonii Van de Vijver et Verleyen sp. nov., whereas the former variety elliptica is brought to species level: P. ellipticomanguinii nom. et stat. nov. The morphology, ecology and distribution of all species are discussed and a morphological comparison is made.

Species composition and toxicity of the genus Pseudo-nitzschia in Taiwan Strait, including P. chiniana sp. nov. and P. qiana sp. nov.

In a field survey in the Taiwan Strait during April 2016, the species composition and the domoic acid production of the diatom genus Pseudo-nitzschia were investigated. A total of 80 strains of Pseudo-nitzschia were established, and species identification was determined based on a combination of morphological and molecular data. Fourteen taxa were recognized, i.e., P. americana, P. brasiliana, P. calliantha, P. cuspidata, P. galaxiae, P. lundholmiae, P. multiseries, P. multistriata, P. pseudodelicatissima, P. pungens var. aveirensis, P. pungenus var. pungens and P. sabit, as well as two novel species P. chiniana C.X. Huang & Yang Li and P. qiana C.X. Huang & Yang Li. Morphologically, P. chiniana is characterized by striae comprising one or two rows of poroids, and valve ends that are normally dominated by two rows of poroids within each stria. Whereas P. qiana is unique by having a narrow valve width (1.3–1.5 μm) and sharply pointed valve ends. Both taxa constitute their own monophyletic lineage in the phylogenetic analyses inferred from LSU and ITS2 rDNA, and are well differentiated from other Pseudo-nitzschia species. Pseudo-nitzschia chiniana forms a group with P. abrensis and P. batesiana in LSU and ITS trees, whereas P. qiana is sister to P. lineola. When comparing ITS2 secondary structure, five CBCs and seven HCBCs are recognized between P. chiniana and P. abrensis, and four CBCs and ten HCBCs between P. chiniana and P. batesiana. Two CBCs and eight HCBCs are found between P. qiana with P. lineola. The ability of the strains to produce domoic acid was assessed, including a potential toxin induction by the presence of brine shrimps. Results revealed production of domoic acid in six strains belonging to three species. Without presence of brine shrimps, cellular DA (pDA) was detected in four P. multiseries strains (1.6 ± 0.3, 26.6 ± 2.7, 68.3 ± 4.2 and 56.9 ± 4.7 fg cell−1, separately), one strain of P. pseudodelicatissima (0.8 ± 0.2 fg cell−1) and one strain of P. lundholmiae (2.5 ± 0.4 fg cell−1). In the presence of brine shrimps, pDA contents increased significantly (p < 0.05) in P. lundholmiae (strain MC4218) and P. multiseries (strain MC4177), from 2.5 ± 0.4 to 8.9 ± 0.7 and 1.6 ± 0.3 to 37.2 ± 2.5 fg cell−1 respectively.