Oocyte production and sperm utilization patterns in semi-fertile strains of Caenorhabditis elegans

BACKGROUND: Caenorhabditis elegans hermaphrodites are capable of producing hundreds of progeny. However, genetic and environmental factors can keep many animals from attaining their full reproductive potential. In these situations, efficient use of any functional gametes becomes more important for reproductive success. To learn about this aspect of C. elegans reproductive biology, we examined oocyte production and sperm utilization patterns in a unique collection of semi-fertile sperm function mutants. RESULTS: In the mutants examined here, broods can be very small but sperm induced high levels of ovulation. Ovulation rates reach maximum levels between the first and second day of adulthood. Ovulations rates remain high during the reproductive period and gradually decline with age. These results further demonstrate a decoupling of the ability of sperm to fertilize oocytes and induce ovulation. We also observe that in our semi-fertile mutants the peak of successful fertilization events precedes the bulk of oocyte production. Mixing populations of functional and nonfunctional sperm under conditions without sperm competition also shows that functional sperm are utilized efficiently. Although overall brood size can be similar for different mutant strains, slight differences in the pattern of sperm utilization in these strains can lead to significant differences in resource utilization and population growth. CONCLUSIONS: This study represents the first detailed description of oocyte and progeny production patterns over the entire reproductive period for wild-type and fertility impaired strains of C. elegans. The phenotype of our mutants provide an ideal system for studying sperm utilization patterns since they only affect one major process, the ability to fertilize oocytes. In semi-fertile mutants, the nature of the reproductive process and/or specific molecular mechanisms ensures that any functional sperm are utilized quickly. Only a fraction of the sperm produced by our semi-sterile mutants are functional as opposed to every sperm having a low but equal chance of fertilizing an oocyte. In addition to the number of progeny produced, the pattern of progeny production can have an important influence on the dynamics of population growth

VocaLiST: An Audio-Visual Synchronisation Model for Lips and Voices

In this paper, we address the problem of lip-voice synchronisation in videos containing human face and voice. Our approach is based on determining if the lips motion and the voice in a video are synchronised or not, depending on their audio-visual correspondence score. We propose an audio-visual cross-modal transformer-based model that outperforms several baseline models in the audio-visual synchronisation task on the standard lip-reading speech benchmark dataset LRS2. While the existing methods focus mainly on the lip synchronisation in speech videos, we also consider the special case of singing voice. Singing voice is a more challenging use case for synchronisation due to sustained vowel sounds. We also investigate the relevance of lip synchronisation models trained on speech datasets in the context of singing voice. Finally, we use the frozen visual features learned by our lip synchronisation model in the singing voice separation task to outperform a baseline audio-visual model which was trained end-to-end. The demos, source code, and the pre-trained model will be made available on https://ipcv.github.io/VocaLiST/Comment: Submitted to Interspeech 2022; Project Page: https://ipcv.github.io/VocaLiST

Use of SNPs to determine the breakpoints of complex deficiencies, facilitating gene mapping in Caenorhabditis elegans

BACKGROUND: Genetic deletions or deficiencies have been used for gene mapping and discovery in various organisms, ranging from the nematode Caenorhabditis elegans all the way to humans. One problem with large deletions is the determination of the location of their breakpoints. This is exacerbated in the case of complex deficiencies that delete a region of the genome, while retaining some of the intervening sequence. Previous methods, using genetic complementation or cytology were hampered by low marker density and were consequently not very precise at positioning the breakpoints of complex deficiencies. The identification of increasing numbers of Single Nucleotide Polymorphisms (SNPs) has resulted in the use of these as genetic markers, and consequently in their utilization for defining the breakpoints of deletions using molecular biology methods. RESULTS: Here, we show that SNPs can be used to help position the breakpoints of a complex deficiency in C. elegans. The technique uses a combination of genetic crosses and molecular biology to generate robust and highly reproducible results with strong internal controls when trying to determine the breakpoints of deficiencies. The combined use of this technique and standard genetic mapping allowed us to rapidly narrow down the region of interest in our attempts to clone a gene. CONCLUSION: Unlike previous methods used to locate deficiency breakpoints, our technique has the advantage of not being limited by the amount of starting material. It also incorporates internal controls to eliminate false positives and negatives. The technique can also easily be adapted for use in other organisms in which both genetic deficiencies and SNPs are available, thereby aiding gene discovery in these other models

Y chromosome microdeletion and cytogenetic findings in male infertility: A cross-sectional descriptive study

Background: Infertility affects about 15% of couples worldwide, and the male factor alone is responsible for approximately 50% of the cases. Genetic factors have been found to play important roles in the etiology of azoospermia and severe oligospermia conditions that affect 30% of individuals seeking treatment at infertility clinics. Objective: To determine the frequency of chromosomal abnormalities and Y chromosome microdeletion in infertile men. Materials and Methods: A total of 100 infertile men with abnormal semen parameters were included in this study from 2014 to 2018. Chromosomal analysis was carried out using standard G-banding using Trypsin Giemsa protocol. Multiplex polymerase chain reaction was used to determine the Y microdeletion frequency. Results: All participants were aged between 22 and 48 yr with a mean and standard deviation of 35.5 ± 5.1. Of the 100 subjects included in the study, three had Klinefelter syndrome-47,XXY, one had balanced carrier translocation- 46,XY,t(2;7)(q21;p12), one with the balanced carrier translocation with inversion of Y chromosome 45,XY,der(13;14)(q10;q10),inv(Y), one had polymorphic variant of chromosome 15, one had Yqh-, and another had an inversion of chromosome 9. Y chromosome microdeletion of Azoospermia factor c region was observed in 2% of the cases. To the best of our knowledge, the current study is the first reported case with unique, balanced carrier translocation of chromosome 2q21 and 7p21. Conclusion: The present study emphasizes the importance of routine cytogenetic screening and Y microdeletion assessment for infertile men, which can provide specific and better treatment options before undergoing assisted reproductive technology during genetic counseling. Key words: Chromosome aberrations, Infertility, Chromosome deletion, Polymerase chain reaction, Sequence tagged sites

The palm oil industry and noncommunicable diseases

This is the final version. Available on open access from the World Health Organization via the DOI in this recordLarge-scale industries do not operate in isolation, but have tangible impacts on human and planetary health. An often overlooked actor in the fight against noncommunicable diseases is the palm oil industry. The dominance of palm oil in the food processing industry makes it the world’s most widely produced vegetable oil. We applied the commercial determinants of health framework to analyse the palm oil industry. We highlight the industry’s mutually profitable relationship with the processed food industry and its impact on human and planetary health, including detrimental cultivation practices that are linked to respiratory illnesses, deforestation, loss of biodiversity and pollution. This analysis illustrates many parallels to the contested nature of practices adopted by the alcohol and tobacco industries. The article concludes with suggested actions for researchers, policy-makers and the global health community to address and mitigate the negative impacts of the palm oil industry on human and planetary health.Wellcome Trus

The selectivity and specificity of autophagy in drosophila

Autophagy is a process of cellular self-degradation and is a major pathway for elimination of cytoplasmic material by the lysosomes. Autophagy is responsible for the degradation of damaged organelles and protein aggregates and therefore plays a significant role in cellular homeostasis. Despite the initial belief that autophagy is a nonselective bulk process, there is growing evidence during the last years that sequestration and degradation of cellular material by autophagy can be accomplished in a selective and specific manner. Given the role of autophagy and selective autophagy in several disease related processes such as tumorigenesis, neurodegeneration and infections, it is very important to dissect the molecular mechanisms of selective autophagy, in the context of the system and the organism. An excellent genetically tractable model organism to study autophagy is Drosophila, which appears to have a highly conserved autophagic machinery compared with mammals. However, the mechanisms of selective autophagy in Drosophila have been largely unexplored. The aim of this review is to summarize recent discoveries about the selectivity of autophagy in Drosophila

ANALYSIS OF COMPLEX CHROMOSOMAL ABNORMALITIES IN A CASE OF MULTIPLE MYELOMA USING SPECTRAL KARYOTYPING

Objective: It was proposed to determine the chromosomal abnormalities in a 49-year-old male patient with multiple myeloma (MM) employing both conventional and advanced molecular cytogenetic techniques.Methods: GTG-banding and spectral karyotyping (SKY) on fixed metaphases obtained from LPS-stimulated bone marrow cells and interphase fluorescence in situ hybridization (iFISH) on unsorted marrow cells were carried out to identify genetic markers of prognostic significance.Results: The abnormal chromosomes observed through conventional cytogenetics could be resolved with SKY technique. The translocation t(4;14) (p16;q32) indicating FGFR3/IGH fusion and deletion of 13q14.3 was noticed using iFISH. The genetic abnormalities confirmed a poor prognostic outcome in the patient who died within 6 months of diagnosis.Conclusion: This report emphasizes the need for multicolor FISH techniques besides iFISH to resolve complex abnormalities and to identify cryptic aberrations of importance in risk stratification of MM patients