منصة إيفاد العلمية

د/ الفت ثروت محمد عبد الصالحين

إرسال رسالة

التخصص: Aquatic Ecology

الجامعة: Sohag University

النقاط:

معامل الإنتاج البحثي

الخبرات العلمية

• PhD student, Department of Environmental and Biological Sciences, Faculty of Science and Forestry, University of Easter Finland (Joensuu), Finland, 2020-2023.
• Assistant lecturer, Sohag University, Faculty of Science, Zoology Department, 2019-present. (https://staffsites.sohag-univ.edu.eg/olfat.tharwat)
• Lecturer, Zoology Department, Faculty of Science, Sohag University, June 2023-present. • Vice-Manager of the Post-graduates Unit, Faculty of Science, Sohag University, July2023-present. • Standard member of financial and material resources, Facu
• Ph.D. in Aquatic Ecology, Department of Environmental and Biological Sciences, Faculty of Science, Forestry and Technology, University of Easter Finland (Joensuu), Finland, 2023.

الأبحاث المنشورة

Species-specific differences and temperature-dependence of Na+/K+-ATPase in freshwater mussels Anodonta anatina and Unio tumidus (Bivalvia: Unionidae)

المجلة: Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology

سنة النشر: 2024

تاريخ النشر: 2024-10-07

The predicted global warming of surface waters can be challenging to aquatic ectotherms like freshwater mussels. Especially animals in northern temperate latitudes may face and physiologically acclimate to significant stress from seasonal temperature fluctuations. Na+/K+-ATPase enzyme is one of the key mechanisms that allow mussels to cope with changing water temperatures. This enzyme plays a major role in osmoregulation, energy control, ion balance, metabolite transport and electrical excitability. Here, we experimentally studied the effects of temperature on Na+/K+-ATPase activity of gills in two freshwater mussel species, Anodonta anatina and Unio tumidus. The study animals were acclimated to three ambient temperatures (+4, +14, +24 °C) and Na+/K+-ATPase activity was measured at those temperatures for each acclimation group. Both species had their highest gill Na+/K+-ATPase activity at the highest acclimation temperature. Na+/K+-ATPase activity of gills exhibited species-specific differences, and was higher in A. anatina than U. tumidus in all test groups at all test temperatures. Temperature dependence of Na+/K+-ATPase was confirmed in both species, being highest at temperatures between +4 and + 14 °C when Q10 values in the acclimation groups varied between 5.06 and 6.71. Our results underline the importance of Na+/K+-ATPase of gills for the freshwater mussels in warming waters. Because Na+/K+-ATPase is the driving force behind ciliary motion, our results also suggest that in warming waters A. anatina may be more tolerant at sustaining vigorous ciliary action (associated with elevated respiration rates and filter-feeding) than U. tumidus. Overall, our results indicate great flexibility of the mussel's ecophysiological characteristics as response to changing conditions.

Variations in shell morphology of freshwater mussels Anodonta anatina and Unio tumidus (Bivalvia: Unionidae) from Lake Polvijärvi, Finland

المجلة: Journal of Environmental Studies

سنة النشر: 2024

تاريخ النشر: 2024-03-01

Freshwater mussels play an important role in aquatic ecosystems and have been the subject of numerous ecological and taxonomical studies. The present study investigated the shell morphology of A. anatina and U. tumidus with focusing on the width-length, height-length, and width-height relationships in Lake Polvijärvi, Finland. Both species revealed distinct external shell morphologies, where A. anatina exhibited an elongated shell shape with a slightly curved dorsal margin and a smooth surface, while U. tumidus had a shorter and flat shell with a more swollen umbo region and a rough surface. The correlation analysis demonstrated strong positive relationships between width-length, height-length, and width-height variables for both species (R2 ≥ 0.82). Linear regression models accurately described these relationships indicating that shell width and height increased consistently as shell length increased. Both of A. anatina and U. tumidus exhibited positive slopes in the width-length relationship suggesting a widening of shells with increasing length, however, A. anatina had a higher intercept than U. tumidus indicating a wider shell at a given length in comparison to U. tumidus. In the height-length relationship, both species showed positive relationships, but U. tumidus exhibited a steeper slope indicating a faster rate of increasing shell height with increasing length compared to A. anatina. These findings contribute to understand the patterns of shell morphology for both species; and the observed species-specific dependence have implications for their growth, proportions, ecological adaptations, and shedding light on their ecological niches and evolutionary dynamics.

Reproductive cycle, fecundity and growth of the freshwater mussel Unio tumidus (Bivalvia: Unionidae) from Lake Viinijärvi, Finland

المجلة: Journal of Molluscan Studies

سنة النشر: 2024

تاريخ النشر: 2024-06-27

Freshwater mussels have a substantial role in aquatic ecosystem function and provide valuable ecosystem services, including water filtration, nutrient cycling, habitat creation and sediment stabilization. While they face population declines globally that can negatively affect an ecosystem's health, such as reducing the water quality and increasing the turbidity, lack of information about the basic reproductive biology for most species makes their conservation much more difficult. Here, we monitored a population of Unio tumidus for a year to study its reproductive biology, gonad-dwelling parasites and growth rate in Lake Viinijärvi, Finland. Our data revealed that this species was dioecious with no evidence of hermaphroditism and was non-significantly female-biased (a male to female ratio of 1:1.3). Both sexes of U. tumidus had continuous gametogenesis during the study period with two peaks in the gonadosomatic index (GSI%) during November and May, followed by two clear declines in December and June. Gravidity period (brooding) of embryos or glochidia in the female's outer gills lasted from June to July. Therefore, this population of U. tumidus can be classified as a short-term breeder (tachytictic). The clear decline of GSI% in December might be a strategy that individuals of U. tumidus use to resorb resources back from the gonad for somatic maintenance during winter. Mean length of glochidia was 391 ± 0.049 µm, being among the largest known glochidia for Unionidae. No gonad-dwelling trematode parasites were detected and the population exhibited high fecundity (numbers of oocytes per female), with an average oocyte production of 242,000 ± 18,000. The studied population had a moderate growth rate with a maximum predicted age of 13 years and asymptotic length (the length at which growth slows down while the mussel continues to age, L∞) of 114 mm. Our study provides the first quantitative data and histological analysis of the reproductive biology of U. tumidus, serving as a basis for future research and conservation.

Reproduction cycle, trematode parasitism and growth of freshwater mussel Anodonta anatina (Bivalvia: Unionidae)

المجلة: Hydrobiologia

سنة النشر: 2024

تاريخ النشر: 2024-12-12

Anodonta anatina, a widely distributed Eurasian freshwater mussel, has dramatically declined and listed as endangered species in IUCN Red List in some parts of the Europe. To better understand its basic biology and possible sex-dependent effects of parasitism on reproduction, we investigated the reproductive traits, trematode parasitism and growth between November 2020 and October 2021. Our data from a Finnish population indicates male-biased sex ratio and the gonadal development lasting throughout the year with a bradytictic brooding pattern. Gonadosomatic index of both sexes peaked in May and declined in June. Mature oocytes were smaller sized than those of previously studied unionids, fecundity was fairly low, and the maximum predicted lifespan was 14 years. Gonads were infected with digenean trematode parasites, Rhipidocotyle campanula being the dominant species. Interestingly, trematode infection rate was higher in females than in males. In July, when the water temperature reached its annual maximum, the trematode prevalence also peaked, which was accompanied with 16% of mussels being sterile. The trematode parasitism was thus negatively associated with reproduction, that might become even more affected if parasitism increases along with the predicted climate warming, which should be considered in possible future conservation and aquaculture efforts of this species.

Temperature dependence of SERCA activity in thermally acclimated freshwater mussels Anodonta anatina and Unio tumidus (Bivalvia: Unionidae)

المجلة: Aquaculture

سنة النشر: 2022

تاريخ النشر: 2022-06-30

Similar to other aquatic ectotherms, freshwater mussels are prone to the predicted global warming of surface waters. Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) has a crucial role in regulating intracellular Ca2+ concentration in muscle cells and potentially involved in setting thermal preferences and behaviors of animals. To this end, we examined temperature effects on SERCA activity of adductor and foot muscles in two freshwater mussel species, Anodonta anatina and Unio tumidus. Mussels were acclimated to three different temperatures (+4, +14, +24 °C) and SERCA activity was measured at those temperatures for each acclimation group. SERCA activity of both tissues was much higher in U. tumidus than A. anatina. SERCA activity in the adductor muscle was higher than that in the muscular foot in both species at all test temperatures, and in all acclimation groups. Cold-acclimated (+4 °C) animals of both species tend to conserve energy by turning off SERCA activity in the cold, as 73% of A. anatina and 55% of the U. tumidus individuals did not have measurable SERCA activity in the muscular foot at +4 °C. Partial temperature compensation of SERCA activity occurred only in the adductor muscle of A. anatina as shown by the higher activity in the +4 °C-acclimated animals than in the +14 and +24 °C acclimated animals. Temperature dependence of SERCA was strong (Q10 between 3.05 and 13.14), whereby SERCA activity responds strongly to temperature changes. Strong temperature-dependent up- or down-regulation of muscle SERCA activity in mussels is probably associated with species-specific behaviors including valve gaping, locomotion and reproduction under variable environmental conditions. Importantly, SERCA activity can potentially provide a mechanistic explanation for these behaviors and has likely implications on freshwater mussel aquaculture and conservation.

The joint adverse effects of aged nanoscale plastic debris and their co-occurring benzo[α]pyrene in freshwater mussel (Anodonta anatina)

المجلة: Science of The Total Environment

سنة النشر: 2021

تاريخ النشر: 2021-12-01

Although the presence of small-scale plastics, including nanoscale plastic debris (NPD, size <1 μm), is expected in the environment, our understanding of their potential uptake and biodistribution in organisms is still limited. This mostly is because of the limitations in analytical techniques to characterize NPD in organisms' bodies. Moreover, it is still debatable whether aged NPD can sorb and transfer chemicals into organisms. Here, we apply iron oxide-doped polystyrene nanoparticles (Fe-PS NPs) of 270 nm size to quantify the uptake and biodistribution of NPD in freshwater mussels (Anodonta anatina). The Fe-PS NPs were, first, oxidized using heat-activated potassium persulfate treatments to produce NPD (aged particles). Then, the sorption of benzo[a]pyrene (B[α]P), as a model of organic chemicals, into the aged NPD was studied. Chemical oxidation (i.e. aging) significantly decreased the sorption of B[α]P into the particles over 5 days when compared to pristine particles. After 72-h of exposure, A. anatina accumulated NPD in the gills and digestive gland. When exposed to the mixture of NPD and B[α]P, the number of particles in the gills and digestive gland increased significantly compared to the mussels exposed to NPD alone. Moreover, the mixture of NPD and B[α]P increased the activity of Superoxide dismutase and Catalase enzymes in the exposed mussels when compared to the control and to the NPD alone. The present study provides evidence that aged NPD not only could accumulate and alter the toxicity profile of organic chemicals in aquatic organisms, but the chemicals also could facilitate the uptake of NPD (combined effects).

Reproductive Cycle, Gametogenesis and Embryonic Development of Nitia Teretiuscula (Bivaliva: Unionidae), from the River Nile at Sohag Governorate, Egypt

المجلة: المجلة المصرية لعلم الحيوان

سنة النشر: 2016

تاريخ النشر: 2016-01-12

The present study dealt with the description of the reproductive and gametogenic cycles and the embryonic development of the freshwater mussel Nitia teretiuscula from the River Nile. Macro and micro-anatomy showed that the present species is dioceous and gonadosomatic indices showed that the species is semiannual and had two gonadal growth periods, a short period of gonadal growth from January to March and a long period from April to August. Visceral indices revealed a reciprocal relationship with the gonadosomatic indices of both the two sexes. The recorded sex ratio of females to males was (1.5: 1). The oogenesis displayed five developmental stages; oogonia, previtellogenic oocytes, vitellogenic oocytes, late vitellogenic oocytes and mature ova. Also, spermatogenesis illustrated five developmental stages: spermatogonia, primary spermatocytes, and secondary spermatocytes, spermatids; which clustered to form sperm morula and finally metamorphosed to spermatozoa. Within the gills of females (marsupia), brooding of embryos was occurred till the formation of glochidia larvae. The unfertilized eggs were released from the gonads with distinct germinal vesicle. The fertilized eggs had two polar bodies and a fertilization cone. Successive cleavages were observed. Spiral cleavage, non-ciliated blastula and D-shaped larvae were recorded.

Local and Temporal Distributions and a new Dispersal Phenomenon of the Freshwater Mussel Nitia Teretiuscula (Bivalvia: Unionidae) in the River Nile at Sohag Governorate, Egypt

المجلة: Journal of ecology of Health & Environment

سنة النشر: 2019

تاريخ النشر: 2019-09-01

The unionid freshwater mussel Nitia teretiuscula (Philippi, 1847) was collected from the River Nile at Sohag Governorate. Both the spatial and temporal distributions were investigated using a systematic sampling technique. In addition, the inter-relationships between the abundance of the studied species and some measured environmental factors was examined. The abundance of the mussel fluctuated during most of the year and showed clear favoring for the shallow area near the bank of the river. The organic content of the sediment was the most effective environmental factor on the mussel distribution. The present species showed also a new dispersal phenomenon that is recorded for the first time in family Unionidae. The individuals release many gelatinous structures, named embryophores, that possess many coneshaped arms that help in carrying early stages away by water currents.