Science literature summaries

Healthy cell division: Metaphase: Chromosomes line up at the cell’s center. Anaphase: Chromosomes separate cleanly toward opposite poles. Telophase: Two nuclei form with fully separated DNA. Result: two daughter cells with the correct DNA, stable genome. Unhealthy division with chromatin bridges: Metaphase: Chromosomes may be tangled or improperly aligned. Anaphase: Some chromosomes fail to separate , and their DNA gets stretched between the two poles. Telophase: Thread-like DNA bridges remain between nuclei. Result: DNA may break or mis-segregate, producing cells with abnormal DNA and genomic instability .

  Hydrogen bonds disrupted are mainly between agarose polysaccharide chains (the long sugar chains in agar) Hydrolysis breaks the glycosidic bonds between the sugar monomers in the agar polysaccharide chains.

A  gland  is an organ that produces and releases substances such as hormones, enzymes, or fluids. There are two main types of glands: Endocrine glands  – Release hormones directly into the bloodstream (e.g., thyroid, pituitary, adrenal glands). Exocrine glands  – Release substances through ducts to the surface of organs or the skin (e.g., sweat glands, salivary glands, digestive glands).

  What is a Chromosome Inversion? A chromosome inversion is a type of genetic variation where a segment of a chromosome is flipped and reinserted in the opposite orientation. This rearranges the order of genes within that segment. Key Points About Chromosome Inversions : Structure : Imagine a segment of DNA being cut out, flipped upside down, and placed back into the chromosome. For example: If the original sequence was A-B-C-D , after inversion, it becomes A-D-C-B . Types : Paracentric inversion : The inversion occurs outside the centromere (the central part of the chromosome). Pericentric inversion : The inversion includes the centromere. Polymorphism : Populations can be polymorphic , meaning some individuals have the inverted chromosome arrangement, while others have the "standard" arrangement. These differences can be observed in salivary gland chromosomes, where loops form during pairing (Figure 1 from the study). Recombination Issues : When...

  Flies developed at low temperature (13°C) : Most cold resistant Highest abundance of Wolbachia Flies developed at high temperature (31°C) : Most heat tolerant Highest abundance of Acetobacter Source: https://pubmed.ncbi.nlm.nih.gov/29095113/

Mating duration used by different research groups: 15-30 mins (https://www.sciencedirect.com/science/article/pii/S0022191012002259#s0025) 30 mins (https://www.nature.com/articles/ncomms12322) 90 minutes (https://academic.oup.com/beheco/article/22/1/184/232467?login=false) 2 hours (https://onlinelibrary.wiley.com/doi/full/10.1111/j.1420-9101.2010.01973.x) ~15 mins for mating latency + copulation time (https://academic.oup.com/jinsectscience/article/11/1/67/2492817?login=false#90814333)

"bacteriome highly expresses the coleoptericin A (colA) antimicrobial peptide (AMP), which was shown to prevent endosymbiont escape from the bacteriocytes." "This work provides a striking example of how a conserved immune pathway, initially described as essential in pathogen clearance, also functions in the control of mutualistic associations."  https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0397-9

Nucleoproteins are complex structures made up of proteins and nucleic acids, such as DNA or RNA.  Histone, protamines, ribosomes,  Spermatids are the cells which are produced from the testes as a result of spermatogenesis .  The spermatids develop into spermatozoa or sperms by the process of spermiogenesis .

D. melanogaster gut microbiome, particularly Lactobacillus plantarum and Acetobacter pomorum, increases the pace of host development (Shin et al., 2011; Storelli et al., 2011).

Reduced Richness and Diversity : Lab-raised flies exhibit significantly lower richness and diversity of bacteria compared to wild-caught flies. Specific Strains : Laboratory flies have bacterial strains closely related to those from previous studies, with five strains being >99% identical to previously identified cultured isolates of D. melanogaster. Enterococcus, which was previously found to comprise nearly 50% of the lab bacterial microbiome, is virtually absent in current lab samples. https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1002272#pgen-1002272-g002

 Immunostaining (for Histones), Cytochemical staining (for Protamines), FISH (for lncRNA)

 20-50 ng/uL is the standard concentration for PCR

primary spermatocytes (spermatogenesis) -> meiosis -> elongating spermatids (spermiogenesis). https://www.science.org/doi/10.1126/science.adk9469

 Wolbachia is plural, so use "take", not "takes"

Wolbachia  increased in the relative abundance of gnotobiotic fly lines with  Lb  r But no such observation with gnotobiotic with  At  replicates. source:  https://www.pnas.org/doi/10.1073/pnas.1907787116

 Symbiosis = singular  Symbioses = plural

  Addition of the AAB species  Acetobacter tropicalis  to the food resource ( At  treatment), 2) addition of the LAB species  Lactobacillus brevis  to the food resource ( Lb  treatment), and 3) no microbial inoculation ( No-Ad  treatment).  At  and  Lb  strains were selected as representative AAB and LAB based on their different influences on  D. melanogaster  life history traits, with  At- inoculated flies displaying faster development times and shorter periods of starvation resistance than Lb-inoculated flies https://www.pnas.org/doi/10.1073/pnas.1907787116#sec-1

- Removal of gut bacteria (specially Acetobacter) inhibits oogenesis, accelerates maternal-to-zygotic transition in offspring, and reveals hidden phenotypic variations in mutants. - The Drosophila Aldh gene appears to mediate repressed oogenesis in flies lacking Acetobacter. https://www.nature.com/articles/ncomms11280

Acetobacter pomorum and Acetobacter tropicalis strains can provide thiamine (vitamin B1) to the Drosophila larva https://journals.asm.org/doi/10.1128/mbio.00155-18

" Overall, we did not find an effect of   Wolbachia   on female attractiveness or male mate choice, but we observed variable effects of naturally occurring microbiota on female attractiveness, depending on host genotype, where altering the microbiota decreased attractiveness in some lines, but increased it in others"   https://onlinelibrary.wiley.com/doi/10.1111/jeb.12788

" Finally, we analyze data from two published studies of fecal microbiota transplantation (FMT), finding that high functional redundancy of the recipient’s pre-FMT microbiota raises barriers to donor microbiota engraftment." Source: https://www.nature.com/articles/s41467-020-19940-1

Explore: do not use this word Hypothesis: A scientific explanation but not proven yet Expect:  Density: Relative term, for relative qPCR Titre: Exact amount, for absolute qPCR

Acetobacter are Gram -ve Lactobacillus are Gram +ve

Forward genetics: Start the research with an organism (eg. diseased or natural mutant) and then work backward to discover the genetic basis for it.  Reverse genetics, where specific genes are modified or manipulated to study their effects on a phenotype.

Density = realtive Titer = absolute calculation

Propionic acid promotes larval survival (in low-nutrient food i.e. low yeast). Propionic acid is detected by Laravel chemoreceptors Or30a and Or94b. This propionic acid activity works on Dmel, but not on D. suzukii. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5660182/#:~:text=Propionic%20acid%20in%20the%20culture,medium%20(6.5%25%20yeast).

 10^2 to 10^8 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6069112/

  Lactobacillus produces lactate, which is used by Acetobacter to produce amino acids, which is used by Lactobacillus. https://www.nature.com/articles/s41467-020-18049-9

1st Gen mean life is ~55 days, 2nd Gen has ~68 days, and 3rd Gen has about 72 days. CV has 60 days. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6660043/ 

Both a ntibiotics and  Wolbachia  significantly reduced the biodiversity of the gut microbiota without changing the total microbial load.  https://www.sciencedirect.com/science/article/pii/S0022201116302130#s0005

Wolbachia  strain  w Au spread through Australian populations of  Drosophila simulans  despite not causing CI, [probbaly due to its antiviral effects] https://www.nature.com/articles/s42003-021-02838-z

Wolbachia  density is not correlated with  cytoplasmic incompatibility  intensity. Wolbachia  might induce the defect in male host fertility by immunity-related pathways and thus cause an oxidative damage and cell death in male testes.

D. sechellia breeds poorly on laboratory food  in the absence of the fruit of its normal host plant, Morinda citrifolia ( a medicinal plant )

In bacteria, genes are lowercase italics (e.g. cifA ), while proteins are capitalized without italics (e.g., CifA)

Shfr - Location of Shfr , a new gene that rescues hybrid female viability in crosses between Drosophila simulans females and D. melanogaster males

Typically in centromeres and telomerase. Highly repetitive sequence. Have much fewer genes than euchromatin. Can silence gene expression of euchromatin. Heterochromatin increase with age and are more in males. source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7274899/

Serratia marcescens and Pseudomonas aeruginosa infection was more in axenic flies. Infections were reduced when treated with Lactobacillus Plantarum. quotidian replenishment - need to replenish microbial daily If Lactobacillus is important, then why is it not maintained: Dmel gets rids its gut of most microbes to minimize the risk of acquiring and maintaining potential pathogens. The microbiome may compete with its Drosophila host for nutrients in the gut. Our evidence indicates that Drosophila seeds its food with commensal organisms by depositing fecal matter on its food source on which the bacteria grow. Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3892787/#h2title

 Dmel microbiome is dominated by  Acetic acid bacteria (AABs), mainly genus Acetobacter (Alphaproteobacteria),  Lactic acid bacteria (LABs), mainly the genus Lactobacillus (Firmicutes) (20). And also a strong representation of other taxa, including Gammaproteobacteria (e.g., Stenotrophomonas spp.) and lactobacilli (e.g., Enterococcus spp.) (22, 23). Acetobacter fabarum, Acetobacter pomorum, Acetobacter tropicalis, Lactobacillus brevis, and Lactobacillus plantarum.

 Mutations in Lhr K18 and Hmr U79 genes enable the survival of hybrids that are otherwise lethal in wild types.

23% of genes are DEGs between Drosophila individuals due to differences in body size, weight, etc.  Hence, a pool of 5 or more replicates would yield better result. source: https://www.nature.com/articles/s41598-021-90857-5

Different hosts respond differently to the same Wolbachia strain. Notes: There are more than 100k Wolbachia strains Benefits to host also vary - Vitamin C to Cimex lectularius bedbugs; but virus protection to Dmel. source: https://www.nature.com/articles/s41598-021-90857-5

Axenic males produce only 66% of eggs when mated with CV females compared to CV males crossed with CV females. Also, axenic males mated with axenic females produce only 62% compared to CV couples.  Source: https://www.nature.com/articles/s41598-020-75156-9#:~:text=We%20further%20observed%20that%20the,switch%20of%20the%20female's%20transcriptome.

In Drosophila, Wolbachia enhances learning and memory capacity (LMC) Increase in LMC by Wolbachia by decrease (miRNA) dme-miR-92b and increase crebA source: https://www.sciencedirect.com/science/article/pii/S0965174818302947

  source: https://journals.asm.org/doi/10.1128/mBio.01879-19