Effects of mixtures containing chlordecone and a dechlorinated by-product on hydra regeneration capacity: use of experimental design to evaluate the toxicity risk associated with remediation programs in long-lasting polluted areas

Chlordecone (CLD), an obsolete insecticide, used in the French West Indies between 1972 and 1993, is persistent in the environment but can be dechlorinated either chemically or under the action of microorganisms. Therefore, if soil remediation programs based on these processes are implemented in areas still contaminated today, those will see their concentrations of dechlorinated derivatives increase and these compounds will be also found in freshwater by streaming, leaching and erosion processes. The purpose of the present study was to evaluate, at environmental concentrations, the toxic effects of mixtures of chlordecone and a three-chlorine substituted byproduct. A hydra clone, which has been confirmed to be Hydra vulgaris Pallas, 1766 has been retained for bioassays where the toxicity has been evaluated by regeneration capacity during exposure. Exposure to mixtures is complex to investigate by classical methods, therefore, an experimental design associated to a mathematical model has been used to predict the effects of all the mixtures and to detect the toxic influence of each compound. The predictive model is discussed regarding the stochastic “endocrine disruptor effect” of CLD. At probable environmental concentrations of the compounds in the mixture, results show that impairment of regeneration capacity is explained mostly by the presence of CLD in the mixtures and support the implementation of remediation programs aimed at dechlorination of this persistent organochlorine pesticide.

Indirect in vitro Regeneration of the Medicinal Plant, Aspilia africana, and Histological Assessment at Different Developmental Stages

The medicinal plant, Aspilia africana, has been traditionally used in several African countries to treat many diseases such as tuberculosis, cough, inflammation, malaria, osteoporosis, and diabetes. In this study, we developed a protocol for in vitro propagation of A. africana using indirect shoot organogenesis from leaf and root explants of in vitro-grown seedlings and assessed the tissues at different developmental stages. The highest callus induction (91.9 ± 2.96%) from leaf explants was in the Murashige and Skoog (MS) medium augmented with 1.0 mg/L 6-Benzylaminopurine (BAP) and 1.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) while from root explants, the highest callus induction (92.6 ± 2.80%) was in the same plant tissue culture medium augmented with 0.5 mg/L BAP and 1.0 mg/L 2,4-D. The best shoot regeneration capacity from leaf-derived calli (i.e., 80.0 ± 6.23% regeneration percentage and 12.0 ± 6.23 shoots per callus) was obtained in medium augmented with 1.0 mg/L BAP and 0.05 mg/L α-Naphthaleneacetic acid (NAA); the best regeneration capacity for root-derived calli (i.e., 86.7 ± 6.24% shoot regeneration percentage and 14.7 ± 1.11 shoots per callus) was obtained in the MS medium augmented with 1.0 mg/L BAP, 0.05 mg/L NAA, and 0.1 mg/L Thidiazuron (TDZ). Regenerated plantlets developed a robust root system in 1/2 MS medium augmented with 0.1 mg/L NAA and had a survival rate of 93.6% at acclimatization. The in vitro regenerated stem tissue was fully differentiated, while the young leaf tissue consisted of largely unorganized and poorly differentiated cells with large intercellular airspaces typical of in vitro leaf tissues. Our study established a protocol for the indirect regeneration of A. africana and offers a basis for its domestication, large-scale multiplication, and germplasm preservation. To the best of our knowledge, this is the first study to develop an indirect regeneration protocol for A. africana and conduct anatomical assessment through the different stages of development from callus to a fully developed plantlet.

Disturbance of Mangrove Forest Due To Climate Change: The Prospects of Sundarban

Mangrove forest has a significant importance in protecting natural disaster, environmental sustainability and in local economy. In Bangladesh, only mangrove forest Sundarban also servicing for environmental sustainability, protecting tropical cyclone, local employment generation and so on. Thus, its natural properties are being hampered through people involvement and natural calamities. Moreover, Rapid population growth and climate change stimulating these disturbances of natural properties of Sundarbans. This paper aim at how climate change is disturbing mangrove forest in Bangladesh and how this disturbance may be threatful for future environmental sustainability. Interrelation between climate change and disturbance of Sundarbans has been established through various exiting literature review and for quantifying the amount of disturbance remote sensing data has been applied and future threat of environmental sustainability has been assessed by comparing regeneration capacity of Sundarban after a tropical cyclone and amount of disturbance by a tropical cyclone. Result found that climate change increasing the frequency of natural calamities and affecting significantly on mangrove forest due to its complex bio-diversity and strategic location before regeneration of disturbance. On the other hand, threat of mangroves as well as environment is associated with temperature rising, ice melting and sea level rising are increasing because of frequent occurrence, magnitude as comparing with regeneration capacity.

Analyses of Bone Regeneration Capacity of Freeze-Dried Bovine Bone and Combined Deproteinized–Demineralized Bovine Bone Particles in Mandibular Defects: The Potential Application of Biological Forms of Bovine-Bone Filler

Objective This study aimed to evaluate bone regeneration capacity of FDBX granules compared to composite DBBM/DFDBX granules for filling of bone defect in rabbit mandible. Material and Methods Critical size defects were created in 45 rabbits' mandible. The defect in the control group is left untreated, while in other groups the defects were filled with FDBX granules and composite DBBM/DFDBX granules, respectively. Specimens were collected at 2, 4, and 8 weeks for histology and immunohistochemical analyses. Significant difference is set at p-value < 0.05. Results The osteoblast-osteoclast quantification, osteoblast expression of Runx2, alkaline phosphatase, collagen-I, and osteocalcin, and osteoclast expression of receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) in FDBX groups were statistically comparable (p > 0.05) with the composite group, while OPG/RANKL ratio, bone healing scores, and trabecular area were significantly higher (p < 0.05) in the composite compared to FDBX group. Conclusion Composite DBBM/DFDBX granules, within the limitation of this study, has better bone forming capacity than FDBX granules for filling of bone defects in the mandible.

Validating Field Regeneration Capacity for Selected Accessions of Gossypium hirsutum Using Callus Induction and Regeneration Capacity

Gossypium hirsutm undergoes a rapid clonal propagation to regenerate a mature plant through tissue culture. In this research, cotton leaf regeneration level for 21 accessions in the field (new leaves) was observed after the first harvest, and a comparison between field regeneration level and callus induction with its regeneration capacity (new shoots and roots) for the same 21 accessions was carried out. During the flowering stage of Gossypium hirsutum, biochemical (Proline), physiological (chlorophyll and carotenoid content) analysis was carried out. Phenotypic observations (plant height, leaf area, fresh leaf weight, dry leaf weight, flower and boll number) were also carried out on 21 accessions for each accession. Callus induction and regeneration capacity of roots and shoots for hypocotyl, cotyledons and shoot tip tissues was used to validate field regeneration capacity through analysis of variance. ZS061, LuMian378, JiMian863, and ZS065 have highest drought tolerance while ZhongMianSuo24, LiaoYangDuoMaoMian, and BeiZheGongSheMian have the lowest tolerance to drought stress. Accessions with both field and callus regeneration capacity were identified.

Detailed morphological analysis of axolotl sperm

The axolotl has extraordinary regeneration capacity compared to other vertebrates. This remarkable potential has been attributed to its life-long neoteny, characterized by the exhibition of embryonic characteristics at the adult stage. A recent study provided a detailed morphological analysis of the sperm morphology of the Ambystoma mexicanum using routine and detailed histological techniques. The primary purpose of the present study is to describe a simple and inexpensive method for evaluating the morphology of axolotl sperm. In this study, spermatophore structures were collected and spread on slides and air-dried. The slides were stained with periodic acid Schiff, toluidine blue, Masson’s trichrome, Giemsa, Spermac, and Diff-Quik dye for a morphological examination. The slides were coated with gold/palladium for a scanning electron microscopy examination. The sperm of the axolotl consisted of an elongated head, a neck, and a flagellum covered with an undulating membrane. The lengths of the midpiece, tail, and head were 8.575 µm, 356.544 µm, and 103.661 µm, respectively. In the flagellum part, the wavy membrane structure, whose function has not been explained, surrounds the tail. The data obtained from this study will constitute an important step in designing future research on the reproductive and regeneration capacity of the axolotl.

Sex and Regeneration

Regeneration is usually regarded as a unique plant or some animal species process. In reality, regeneration is a ubiquitous process in all multicellular organisms. It ranges from response to wounding by healing the wounded tissue to whole body neoforming (remaking of the new body). In a larger context, regeneration is one facet of two reproduction schemes that dominate the evolution of life. Multicellular organisms can propagate their genes asexually or sexually. Here I present the view that the ability to regenerate tissue or whole-body regeneration is also determined by the sexual state of the multicellular organisms (from simple animals such as hydra and planaria to plants and complex animals). The above idea is manifested here by showing evidence that many organisms, organs, or tissues show inhibited or diminished regeneration capacity when in reproductive status compared to organs or tissues in nonreproductive conditions or by exposure to sex hormones.

The roles of signaling pathways in cardiac regeneration

: In recent years, knowledge of cardiac regeneration mechanisms has dramatically expanded. Regeneration can replace lost parts of organs, common among animal species. The heart is commonly considered an organ with terminal development, which has no reparability potential during post-natal life; however, some intrinsic regeneration capacity has been reported for cardiac muscle, which opens novel avenues in cardiovascular disease treatment. Different endogenous mechanisms were studied for cardiac repairing and regeneration in recent decades. Survival, proliferation, inflammation, angiogenesis, cell-cell communication, cardiomyogenesis, and anti-aging pathways are the most important mechanisms that have been studied in this regard. Several in vitro and animal model studies focused on proliferation induction for cardiac regeneration reported promising results. These studies have mainly focused on promoting proliferation signaling pathways and demonstrated various signaling pathways such as Wnt, PI3K/Akt, IGF-1, TGF-β, Hippo, and VEGF signaling cardiac regeneration. Therefore, in this review, we intended to discuss the connection between different critical signaling pathways in cardiac repair and regeneration.

Abstract MP25: Defining The Role Of Renin Lineage Cells During Regeneration After Release Of Partial Ureteral Obstruction In Neonatal Mice.

Our previous study on a partial unilateral ureteral obstruction (pUUO) model in neonatal mice showed that the release of obstruction halts the progression of kidney damage and leads to a remarkable repair of the kidney with improvement in renal blood flow. In the current study, we aim to understand the role of mural cells of the renin lineage during kidney damage and repair in the neonatal pUUO model. Our results show a marked increase in renin-positive areas in kidneys obstructed for 3W (Sham-3W: 0.70±0.10%, n=3; Obstructed-3W: 1.82±0.43%, n=3). However, relief of obstruction at 1W restored the renin-positive areas to sham levels (Post-release-2W: 0.70±0.09%; n=3). Lineage tracing using Ren1 d Cre;mTmG mice revealed a significant increase in GFP+ cells in the obstructed kidneys, with a decrease post-release. To understand further the dynamic changes in cells of renin lineage due to obstruction, we ablated the renin cells using DTA (Diphtheria toxin subunit A). We crossed the DTA fl/fl mice with Ren1 d -DTA het ;Ren1 d Cre;mTmG mice and performed pUUO in the resultant pups with DTA in the renin cells (DTA+). DTA+ animals showed thinning of the renal vasculature and a 90% reduction in renin-positive area compared to controls [Control: 0.70±0.10% (n=3); DTA+: 0.06±0.03% (n=3)]. In addition, there was no significant increase in the renin-positive area post-obstruction [Sham-3W: 0.06±0.04% (n=3); Obstructed-3W: 0.12±0.05% (n=4); Post-release-2W: 0.08±0.03% (n=4)]. These results indicate that ablation of renin cells abolished the obstruction-mediated surge in the renin expression. However, measurement of interstitial collagen positive area indicated that despite the absence of renin cells, the fibrotic damage due to obstruction recovered remarkably post-release [Collagen positive area: Sham-3W: 3.38±0.67% (n=3) Obstructed-3W: 62.98±31.50% (n=3); Post-release-2W: 10.93±5.46% (n=4)]. Similarly, vascular damage induced by persistent obstruction and recovery following the relief of obstruction was similar between the DTA+ and non-DTA animals. Our results imply that though the renin and renin lineage cells increase in obstructed kidneys, ablation of renin cells does not affect the regeneration capacity of kidneys following the relief of obstruction.