Centrosome and microtubule functions and dysfunctions in meiosis: implications for age-related infertility and developmental disorders

2015 ◽  
Vol 27 (6) ◽  
pp. 934 ◽  
Author(s):  
Heide Schatten ◽  
Qing-Yuan Sun
Keyword(s):  
Reproductive Success ◽  
Microtubule Dynamics ◽  
Core Structure ◽  
Reproductive Capacity ◽  
Farm Animals ◽  
Meiotic Spindle ◽  
Success Rates ◽  
Oocyte Aging ◽  
The Impact ◽  
Centrosomal Proteins

The effects of oocyte aging on meiotic spindle dynamics have been well recognised, but the mechanisms underlying the effects are not well understood. In this paper we review the role of centrosomes and the microtubule cytoskeleton in meiotic spindle formation and maintenance, and the impact of oocyte aging on spindle integrity resulting in centrosome and microtubule dysfunctions that are associated with aneuploidy. Loss of spindle integrity includes dispersion of proteins from the centrosome core structure and loss of attachment of microtubules to centrosomes and kinetochores, which will result in abnormal chromosome separation. The inability of centrosomal proteins to accurately associate with the centrosome structure may be the result of destabilisation of the core structure itself or of microtubule destabilisation at the centrosome-facing microtubule areas that are acetylated in fresh oocytes but may not be acetylated in aging oocytes. Microtubule destabilisation prevents accurate motor-driven transport of centrosomal proteins along microtubules to form and maintain a functional centrosome. Other factors to form and maintain the MII spindle include signal transductions that affect microtubule dynamics and stability. Understanding the mechanisms underlying centrosome and microtubule dysfunctions during oocyte aging will allow diagnosis and analysis of oocyte quality and abnormalities as important aspects for targeted treatment of aging oocytes to extend or restore viability and developmental capacity. New therapeutic approaches will allow improvements in reproductive success rates in IVF clinics, as well as improvements in reproductive success rates in farm animals. This review is focused on: (1) centrosome and microtubule dynamics in fresh and aging oocytes; (2) regulation of centrosome and/or microtubule dynamics and function; and (3) possible treatments to extend the oocyte’s reproductive capacity and viability span.

scholarly journals Male reproductive ageing: a tale of the whole ejaculate

Reproduction ◽  
2019 ◽  
Vol 158 (6) ◽  
pp. R219-R229 ◽  
Author(s):  
Claudia Fricke ◽  
Mareike Koppik
Keyword(s):  
Reproductive Success ◽  
Conformational Changes ◽  
Seminal Fluid ◽  
Reproductive Capacity ◽  
Male Reproductive Success ◽  
Seminal Fluid Proteins ◽  
Area Of Interest ◽  
General Decline ◽  
Age Dependent ◽  
The Impact

Ageing is nearly ubiquitous and encompasses all biological functions. We here focus on age-dependent changes in male reproductive capacity across a broad range of animal taxa. While there has been a long-standing focus on mating ability and overall reproductive success, we here highlight the underlying mechanisms that explain loss in fertilisation capacity in ageing males. Fertilisation is mediated by not only the presence of sperm, but also the cocktail of seminal fluid proteins that ensure sperm survival, capacitation and interaction with female physiology. Sperm ageing has received much attention in studies of male reproductive senescence; however, post-mating processes include a number of interlocked steps that together cumulate in successful fertilisation. As such we consider male ability to elicit female post mating responses such as uterine conformational changes, sperm storage and ovulation and the components within the ejaculate that mediate these post-mating processes. For the latter seminal fluid proteins are key and hence we reflect on age-dependent changes in quality of the entire ejaculate and its consequences for male reproductive capacity. While first studies accrue and highlight that changes in the non-sperm fraction can explain substantial variation in senescent male reproductive success and male ability to induce post-mating responses necessary for fertilisation many open questions still remain that warrant further investigations. One being what the potential age-dependent changes in composition are or whether there is a general decline and how this interacts with sperm to affect fertilisation success. Further, the impact females might have to ameliorate these changes will be an area of interest.

Influence of DAFS-25+polizon composition on blood and functional state of liver of steers at fattening

2020 ◽  
pp. 15-18
Author(s):  
Inna R. Kilmetova ◽  
◽  
Igor A. Rodin ◽  
Nazira I. Khayrullina ◽  
Nikolay G. Fenchenko ◽  
...  
Keyword(s):  
Functional State ◽  
White Blood Cells ◽  
Live Weight ◽  
The Body ◽  
Farm Animals ◽  
Control Group ◽  
Standard Diet ◽  
The Impact ◽  
Experimental Group ◽  
Stimulation Of

Summary. The disbalanced feeding and the uneven distribution of micro- and macroelements in the environment leads to a trace element, in particular hypomelanosis. To accelerate the growth and preservation of young farm animals include in the diet of various biological additives and drugs, which include selenium. For stimulation of weight gain in the livestock industry, as well as for the prevention and treatment of pathological processes in addition to micro - and macrouse amino acids, primarily methionine. The aim of this work was to study the influence of composition of DAFS-25+Polizon on morpho-biochemical parameters of blood and functional state of the liver in fattening bulls of black-motley breed in the conditions of the Republic of Bashkortostan. Experiments using were conducted on bull-calves of black-motley breed of the properties in the properties age from 6 to 15 months. The first experimental group during the experiment was additionally given the composition of DAFS-25+Polizon at a dose of 2 mg/kg, the animals of the control group received a standard diet. To assess the impact of the composition DAFS-25+Polizon on metabolism cattle studied morphological and biochemical indicators of blood and conducted histological examination of the liver. It is established that the use of the composition of DAFS-25+Polizon at a dose of 2 mg/kg increases the number of erythrocytes and hemoglobin in the experimental group and reduces the amount of white blood cells. The serum content of total protein, phosphorus and calcium increases in the group of experimental animals. Microscopic examination of the liver revealed no changes in the structure of the organ and hepatocytes in the experimental group, whereas in the control group hemodynamic disorders and dystrophic changes in liver cells were observed. Thus, the use of the composition DAFS-25+Polizon at a dose of 2 mg/kg of live weight in fattening bulls black-and-white breed contributes to the increase of redox processes in the body, stimulation of metabolism, prevent the development of liver disorders of cellular mechanisms of metabolism, optimizes the structure of the liver, which generally provides higher productivity.

Kalahari Cheetahs

2017 ◽  
Author(s):  
Gus Mills ◽  
Margaret Mills
Keyword(s):  
Reproductive Success ◽  
Spatial Ecology ◽  
Prey Selection ◽  
Arid Ecosystems ◽  
Foraging Success ◽  
Ecological Processes ◽  
Demographic Groups ◽  
Important Prey ◽  
Hunting Behaviour ◽  
The Impact

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.

Impact of a New Teaching and Learning Approach in an Introductory Programming Course

2017 ◽  
Vol 55 (6) ◽  
pp. 789-819 ◽  
Author(s):  
Sohail Iqbal Malik ◽  
Jo Coldwell-Neilson
Keyword(s):  
Teaching And Learning ◽  
Positive Impact ◽  
Dropout Rates ◽  
Success Rates ◽  
Final Exam ◽  
Introductory Programming ◽  
New Approach ◽  
Course Materials ◽  
Didactic Triangle ◽  
The Impact

High failure and dropout rates are reported in introductory programming (IP) courses in different studies despite extensive research attempting to address the issue. In this study, we introduced an ADRI (Approach, Deployment, Result, Improvement) approach in the teaching and learning process of an IP course to improve learning and success rates. All three entities of the didactic triangle (student, instructor, and content) were involved in the research to better understand and execute the proposed approach. The IP course materials were redesigned based on the ADRI approach, and an editor was developed to promote the new approach and encourage students to complete the various stages required in the approach. Two surveys were conducted, and final exam grades over four semesters were compared with determine the impact of including the ADRI approach in the course. We concluded that the ADRI approach provides a positive impact on outcomes that the students achieved during the course. It engages students in practicing their programming skills and provides a new presentation style for examples and exercises which discourages students from taking programming shortcuts. It not only helps to reduce the failure and, significantly, the dropout rates from the IP course but also impacts positively on all students who passed the IP course.

scholarly journals The impact of chromosomes and centrosomes on spindle assembly as observed in living cells.

1995 ◽  
Vol 129 (5) ◽  
pp. 1287-1300 ◽  
Author(s):  
D Zhang ◽  
R B Nicklas
Keyword(s):  
Spindle Assembly ◽  
Living Cells ◽  
Microtubule Dynamics ◽  
Specific Site ◽  
Polarization Microscopy ◽  
Spindle Microtubule ◽  
Single Chromosome ◽  
Bipolar Spindle ◽  
The Impact

We analyzed the role that chromosomes, kinetochores, and centrosomes play in spindle assembly in living grasshopper spermatocytes by reconstructing spindles lacking certain components. We used video-enhanced, polarization microscopy to distinguish the effect of each component on spindle microtubule dynamics and we discovered that both chromosomes and centrosomes make potent and very different contributions to the organization of the spindle. Remarkably, the position of a single chromosome can markedly affect the distribution of microtubules within a spindle or even alter the fate of spindle assembly. In an experimentally constructed spindle having only one chromosome, moving the chromosome to one of the two poles induces a dramatic assembly of microtubules at the nearer pole and a concomitant disassembly at the farther pole. So long as a spindle carries a single chromosome it will persist normally. A spindle will also persist even when all chromosomes are detached and then removed from the cell. If, however, a single chromosome remains in the cell but is detached from the spindle and kept in the cytoplasm, the spindle disassembles. One might expect the effect of chromosomes on spindle assembly to relate to a property of a specific site on each chromosome, perhaps the kinetochore. We have ruled out that possibility by showing that it is the size of chromosomes rather than the number of kinetochores that matters. Although chromosomes affect spindle assembly, they cannot organize a spindle in the absence of centrosomes. In contrast, centrosomes can organize a functional bipolar spindle in the absence of chromosomes. If both centrosomes and chromosomes are removed from the cell, the spindle quickly disappears.

scholarly journals Understanding the seasonality of performance resilience to climate volatility in Mediterranean dairy sheep

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Valentina Tsartsianidou ◽  
Vanessa Varvara Kapsona ◽  
Enrique Sánchez-Molano ◽  
Zoitsa Basdagianni ◽  
Maria Jesús Carabaño ◽  
...  
Keyword(s):  
Genetic Control ◽  
Milk Production ◽  
Eastern Mediterranean ◽  
Meteorological Data ◽  
Genetic Correlations ◽  
Farm Animals ◽  
Seasonal Effects ◽  
Cold Weather ◽  
Adverse Weather ◽  
The Impact

AbstractAs future climate challenges become increasingly evident, enhancing performance resilience of farm animals may contribute to mitigation against adverse weather and seasonal variation, and underpin livestock farming sustainability. In the present study, we develop novel seasonal resilience phenotypes reflecting milk production changes to fluctuating weather. We evaluate the impact of calendar season (autumn, winter and spring) on animal performance resilience by analysing 420,534 milk records of 36,908 milking ewes of the Chios breed together with relevant meteorological data from eastern Mediterranean. We reveal substantial seasonal effects on resilience and significant heritable trait variation (h2 = 0.03–0.17). Resilience to cold weather (10 °C) of animals that start producing milk in spring was under different genetic control compared to autumn and winter as exemplified by negative genetic correlations (− 0.09 to − 0.27). Animal resilience to hot weather (25 °C) was partially under the same genetic control with genetic correlations between seasons ranging from 0.43 to 0.86. We report both favourable and antagonistic associations between animal resilience and lifetime milk production, depending on calendar season and the desirable direction of genetic selection. Concluding, we emphasise on seasonal adaptation of animals to climate and the need to incorporate the novel seasonal traits in future selective breeding programmes.

scholarly journals Effects of herbivory and its timing on reproductive success of a tropical deciduous tree

2020 ◽  
Vol 126 (5) ◽  
pp. 957-969
Author(s):  
Enya N Quiroz-Pacheco ◽  
Francisco Mora ◽  
Karina Boege ◽  
César A Domínguez ◽  
Ek del-Val
Keyword(s):  
Reproductive Success ◽  
Structural Equation ◽  
Structural Equation Models ◽  
Pollen Grains ◽  
Leaf Damage ◽  
Deciduous Tree ◽  
Herbivore Damage ◽  
Male And Female ◽  
Foliar Damage ◽  
The Impact

Abstract Background and Aims The implications of herbivory for plant reproduction have been widely studied; however, the relationship of defoliation and reproductive success is not linear, as there are many interacting factors that may influence reproductive responses to herbivore damage. In this study we aimed to disentangle how the timing of foliar damage impacts both male and female components of fitness, and to assess when it has greater impacts on plant reproductive success. Methods We measured herbivore damage and its effects on floral production, male and female floral attributes as well as fruit yield in three different phenological phases of Casearia nitida (Salicaceae) over the course of two consecutive years. Then we tested two models of multiple causal links among herbivory and reproductive success using piecewise structural equation models. Key Results The effects of leaf damage differed between reproductive seasons and between male and female components of fitness. Moreover, the impact of herbivory extended beyond the year when it was exerted. The previous season’s cumulated foliar damage had the largest impact on reproductive characters, in particular a negative effect on the numbers of inflorescences, flowers and pollen grains, indirectly affecting the numbers of infructescences and fruits, and a positive one on the amount of foliar damage during flowering. Conclusions For perennial and proleptic species, the dynamics of resource acquisition and allocation patterns for reproduction promote and extend the effects of herbivore damage to longer periods than a single reproductive event and growing season, through the interactions among different components of female and male fitness.

scholarly journals FEATURES OF SEASONAL MANIFESTATION OF BRUCELLOSIS INFECTION AMONG THE POPULATION OF THE REPUBLIC OF TAJIKISTAN

2019 ◽  
Vol 1 (1) ◽  
pp. 63-67
Author(s):  
K. M. Kurbonov ◽  
E. G. Simonova ◽  
N. N. Filatov
Keyword(s):  
Incidence Rate ◽  
Preventive Measures ◽  
Climatic Conditions ◽  
Annual Incidence ◽  
Farm Animals ◽  
Annual Incidence Rate ◽  
Epidemiological Analysis ◽  
Economic Transformations ◽  
The Republic ◽  
The Impact

The aim of this work was to study modern manifestations of seasonal brucellosis among the population of the Republic of Tajikistan. The materials and methods: of the study were the official statistics, as well as the results of previously performed studies on the risk assessment of the incidence in population. A retrospective epidemiological analysis of annual incidence rate for the period from 1997 to 2016 was conducted, depending on the most significant social and environmental risk factors. Results. The article shows the impact on the annual incidence rate of socio-economic transformations, including the privatization of collective livestock farms, accompanied by the massive movement of farm animals to private ownership, the loss of practice in animal breeding, and changes in environmental and climatic conditions. Against the background of the intensification of sheep breeding, there is a tendency in seasonality smoothing and shifting the maximum levels of population incidence of brucellosis to the spring season. Conclusion. The modern features of seasonal manifestation of brucellosis infection in the Republic of Tajikistan make it necessary to apply a differentiated approach to planning and conducting preventive measures in various areas of the country.

scholarly journals КЛІНІКО–ГЕМАТОЛОГІЧНІ ПОКАЗНИКИ КОРІВ ПІВНІЧНО–СХІДНОЇ БІОГЕОХІМІЧНОЇ ЗОНИ УКРАЇНИ ЗА РІЗНИХ ПЕРІОДІВ ЛАКТАЦІЇ

2016 ◽  
Vol 18 (3(71)) ◽  
pp. 19-24
Author(s):  
N.G. Grushanska ◽  
V.M. Kostenko
Keyword(s):  
Mineral Metabolism ◽  
Hematological Parameters ◽  
Clinical Signs ◽  
Diagnostic System ◽  
Farm Animals ◽  
Clinical Indicators ◽  
Lactating Cows ◽  
Biochemical Analyzer ◽  
Standard Set ◽  
The Impact

Complicating effect of the adverse technogenic environmental factors that cause changes of biogeocoenose at the interaction with the natural deficiency of biogenic microelements, contributes to appearing and spread of pathology of mineral metabolism in farm animals, particularly in lactating cows. The question about the impact of the northern–eastern biogeochemical zone of Ukraine on the clinical and hematological parameters of cows at lactation’s period is studied insufficiently.The research was conducted in the three farms of Chernihiv region (northern–eastern biogeochemical zone).In the article the materials of our scientific research on determination of the clinical indicators among cows (heart rate, respiratory rate) are represented. The experimental diagnostic system is built on the principle: the sensor – amplifier – generator USW – modulator frequencies – antenna transmitter – receiver antenna – receiver – the computer. Blood was tested on the biochemical analyzer «Labline – 010» with standard set of reagents and the keeping conditions and ration of feeding cows were analized according to conventional methods.The benefits of remote diagnostic device for clinical signs of cows by researcher’s saving time on 37.5% are established. The clinical indicators and main indicators of metabolism among cows of the northern–eastern biogeochemical zones in the 8 – 15, 55 – 65, 150 – 170 day of lactation and 55 – 60 days befor calving are investigated.

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