- Notothylas is a genus of hornworts classified in the division Bryophyta. It reproduces both sexually through spores and vegetatively through parts of the thallus.
- The life cycle involves an alternation of generations between a thalloid gametophyte generation that produces gametes and a sporophyte generation that is bullet-shaped and produces spores.
- Species of Notothylas are found worldwide in moist habitats and vary in characteristics of the thallus, sporophyte structure, and spore ornamentation. Rare species like N. yunannensis from China have unique traits that distinguish them from related species.
The "Telome theory" of Walter Zimmermann (1930, 1952) is the most accepted theory that is based on fossil record and synthesizes the major steps in the evolution of vascular plants.
It describes how the primitive type of vascular plants developed from Rhynia like plants.
The "Telome theory" of Walter Zimmermann (1930, 1952) is the most accepted theory that is based on fossil record and synthesizes the major steps in the evolution of vascular plants.
It describes how the primitive type of vascular plants developed from Rhynia like plants.
This is a detailed presentation on Morphology, anatomy and reproduction of Marchantia spp. with high quality pics and eye capturing transitions and animations
It is called as “living fossil”
The whole order is extincted except one species Ginkgo biloba
This order was occurred in Triassic periods of Mesozoic age (200,000,000 years ago)
This order consists of 16 genera and many species (all in fossil forms except one)
Gnetum: A Powerpoint Presentation on Gymnospemsshivduraigaran
The Gymnosperms are a group of seed-producing plants (spermatophytes) that includes conifers (Pinophyta), cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds". The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species). Roots in some genera have fungal association with roots in the form of micorrhiza(Pinus), while in some others(Cycas) small specialised roots called coralloid roots are associated with nitrogen fixing cyanobacteria.
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpion flies. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater
• Gymnosperms (Gymnos = naked, Sperma = seed) include the small group of plants with naked seeds.
• The Gymnosperms originated in the Devonian period of the Paleozoic Era and formed the supreme vegetation in the Mesozoic Era.
This is a detailed presentation on Morphology, anatomy and reproduction of Marchantia spp. with high quality pics and eye capturing transitions and animations
It is called as “living fossil”
The whole order is extincted except one species Ginkgo biloba
This order was occurred in Triassic periods of Mesozoic age (200,000,000 years ago)
This order consists of 16 genera and many species (all in fossil forms except one)
Gnetum: A Powerpoint Presentation on Gymnospemsshivduraigaran
The Gymnosperms are a group of seed-producing plants (spermatophytes) that includes conifers (Pinophyta), cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds". The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species). Roots in some genera have fungal association with roots in the form of micorrhiza(Pinus), while in some others(Cycas) small specialised roots called coralloid roots are associated with nitrogen fixing cyanobacteria.
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpion flies. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater
• Gymnosperms (Gymnos = naked, Sperma = seed) include the small group of plants with naked seeds.
• The Gymnosperms originated in the Devonian period of the Paleozoic Era and formed the supreme vegetation in the Mesozoic Era.
Soral & Sporangial Characters in Pteridophytes.pdfANAKHA JACOB
Sporangia are Spore bearing structure.
• May be eusporangiate or leptosporangiate.
• Homo- or Heterosporous.
• Terminal/ Lateral/ aggregated into specialized structures.
Tassel is regarded as primitive and acrostichoid condition as advanced.
The sporangia on expanded sporophyll are with or without the
indusium(protective covering).
• The sori lacking indusia are exindusiate or naked (Gleicheniaceae).
Pteridophyta or Pteridophytes are Vascular Plants (also known as "seedless plants") that reproduce and disperse via spores. They do not produce either seeds or flowers.
Additional info:
+ Division Equisetophyta (horsetails & scouring rushes)
+ Division Psilotophyta (whisk ferns)
(This is our report in Botany 2.)
Made by: Sharmine Ballesteros (BS Biology 2A2-1)
This part we will learn about proturan, springtails, dipluran and silverfish. Just basic characteristics for each species. Hope you guys enjoy this part. I will upload the next part later.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
4. GENERAL CHARACTERS:-
• Found in moist habitat.
• Notothylas shows strong resemblance with Anthoceros.
• The genus comprises a number of species which are widely
distributed both in the tropics and temperate zones.
• N. indica, N. levieri, N. chaudhurii and N. javanicus found in India.
• It is the smallest hornwort, grows few centimeter.
• It is also unusual among hornworts, its sporophyte is bullet shaped
and of few millimeters in length.
5. THALLUS
External Features:-
• Rosette like thallus
• Dorsiventral flat
• Thin, delicate, smooth
• Light yellowish
• Toothed or entire irregular processes
• Unicellular, smooth walled rhizoids
• Scales and tuberculate rhizoids are absent.
• On gametophyte, bullet shaped sporophytes arise at margins of thallu
• No midrib seen
6. Internal structure:-
• 6 to 8 layers of cell
• Stomata present on lower epidermis
• Mucilage cavities present at lower
region of thallus forming slime pore
opening.
• In N. javanicus mucilage cavity is
absent.
11. SPOROPHYTE:
• Sporophyte grows out horizontally from the fertile lobes usually in
pairs, its length about 3mm and 0.5mm in diameter.
• It totally dependent on gametophyte.
• The first division in either transverse or vertical in zygote after
fertilization.
• In N. indica and N. levieri the sporogonium is completely enclosed
within the involucre but N. javanicus and N. breutelii it slightly
projected beyond it.
• Supporter columella varies from species to species.
• The pseudoelaters are simple, equal in size and longer than the
spores, with spiral and obique bands.
12. Columellate sporogonium:
• Entire endothecium forms the columella.
• Amphithecium cells divide into inner and
outer.
• N. indica
• N. orbicularis
Non-columellate sporogonium:
• Entire endothecium is fertile and forms
archesporium.
• N. choudhurii
Intermediate species:
• N. breutelii
• N. javanicus
13. DEVELOPMENT:
• Capsule wall is 3-4 layered thick
and lacks stomata.
• Sporogenous tissues around
columella.
• Sporogenous mass in mature
one is differentiated into
unicellular sterile cells and SMC.
• SMC undergo meiosis to form
spore tetrads with exospore and
endospore.
14. spore germination:
• Under favorable conditions the
spore absorbs moisture and
germinates.
• Exospore ruptures and
contents bulged out by small
papilla.
• Minute thallus form by first
transverse and second in
opposite direction with
repeated cell division.
16. Rare and peculiar hornworts:
• N. yunannensis firstly reported in china- Yunnan, Thailand by T. Peng and R.L.
Zhu in 2012 and this was accepted in 2014.
• Its IUCN status is “Data Deficient” because of being small and ephermerial
characters.
• Its thalli is deep green, fascicular rosette, 7-15mm in diameter.
• 1) the irregularly arranged, sub quadrate to sub rectangular epidermal cells
the capsule,
• 2) the absence of the special dehiscence lines of thick-walled cells.
• 3) the vermiculate ornamentation of the spores radiating from a central hollow
on each proximal surface (Peng and Zhu, 2014).
• Notothylas yunannensis is closely related to Notothylas depressispora J. Haseg.
Haseg. and N. irregularis Chantanaorr., which also has vermiculate spores with a
small depression on each proximal facet.
17. References:-
• “Botany for degree students Bryophyta” B.R. VASHISHTA, DR. A.K.
SINHA, DR. ADAERSH KUMAR by S. Chand publications.
• Rare and peculiar hornworts: Notothylas orbicularis and N. javanica
(Notothyladaceae), new genus and species records for Australia.
• Phytotaxa 275 (1): 001–013 http://www.mapress.com/j/pt/ 2016
• Note on Notothylas yunannensis (Notothyladaceae,
Anthocerotophyta), a little known species of hornwort, Sirikanda
Rattanamanee and Sahut Chantanaorrapint*, Department of Biology,
Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla,
90112 Thailand.
• Received: 9 February 2015; Accepted:18 March 2015.
