chat transcript : virology and bacterial genetics

[Lorena]

20:01:44 Lorena enters this room

20:01:45 >[Lorena] Welcome to our chat. Please obey the net etiquette while chatting: try to be pleasant and polite.

20:02:14 [Lorena] hi sweta

20:03:16 [Lorena] hello??

20:03:48 [Lorena] sweta_med>

20:05:37 ninadnashua enters this room

20:07:36 [Lorena] hi ninadna

20:07:45 [ninadnashua] hi

20:07:55 [ninadnashua] when is ur exam

20:08:20 [Lorena] i dont have a date yet

20:08:24 [Lorena] and yours?

20:08:45 [ninadnashua] i have it in xxxx

20:09:02 [Lorena] cool

20:09:13 [Lorena] i will have to decide pretty soon the date

20:09:22 [ninadnashua]>[Lorena] when do they start chat

20:09:31 [ninadnashua] ok

20:09:49 [Lorena] it was supossed to start at 8pm but nobody has showed up

20:10:01 [Lorena] did you study for this topic?

20:10:04 [ninadnashua] ya

20:10:25 [ninadnashua] is it micro im not sure which topic

20:10:27 [Lorena] do you want to start just you and me ?

20:10:54 crusher enters this room

20:11:11 [Lorena] virology and bacterial genetics

20:11:13 [ninadnashua] i prefer if we start after someone comes cause im not that prepare

20:11:21 [Lorena] hi crusher

20:11:23 [ninadnashua] ya

20:11:23 [crusher] hey lorena

20:11:29 [crusher] hi ninad

20:11:32 [ninadnashua] crusher has come we can start

20:11:47 [Lorena] yes

20:12:01 [crusher] is today micro genetic??

20:12:03 [ninadnashua] hi crush

20:12:21 [Lorena] yes and virology

20:12:30 [crusher] ok

20:12:39 jwls29 enters this room

20:12:52 [jwls29] hello all

20:12:54 [Lorena] hi jwls

20:13:17 [crusher] hi jwel

20:13:19 [Lorena] ok lets start

20:13:23 [jwls29] hey crusher

20:14:01 [jwls29] didn't get to microbial genetics

20:14:08 [jwls29] only viruses

20:14:15 [crusher] lets strat

20:14:24 [Lorena] what kind of immune response elicit a naked virus , contrast with an enveloped one

20:16:23 [Lorena] a naked virus elicits mostly a humoral response (ab) , in contrast enveloped virus elicit a cellular response

20:16:38 [ninadnashua] ya

20:16:38 [jwls29] thank you

20:17:10 [Lorena] yw

20:18:19 [Lorena] is rotavirus susceptible to detergents?

20:18:21 [crusher] what is a plasmid?

20:19:02 [Lorena] plasmid i s a piece of DNA (circular) that can replicate independently

20:19:04 [crusher] rota is a segmented virus so i guess

20:19:35 [crusher] it can be suspetible by detregent

20:20:10 [Lorena] rotavirus is a naked virus so...

20:20:34 [jwls29] so no not susceptible to detergents

20:20:39 [crusher] yes plasmid is the part of chromosome (bacterial DNa0

20:20:49 [Lorena] enveloped virus are susceptible to heat, detergents, etc because of the lipid membrane

20:21:14 [Lorena] exactly

20:21:52 [Lorena] thats why enveloped virus (like hepatitis, HIV ) are transmitted parenterally , because they are very susceptible

20:22:28 [Lorena] the naked ones like rotavirus can be transmitted oral fecally

20:23:53 [Lorena] what are the types of DNA that can be found in a bacteria?

20:26:11 [Lorena] did you guys prepare some q's?

20:26:50 [crusher] not really lorena..i did not

20:27:00 [jwls29] a few

20:27:04 [Lorena] ok

20:27:04 [jwls29] not like yours

20:27:26 [jwls29] which are the nakes RNA viruses?

20:27:33 [jwls29] naked

20:27:40 [Lorena] i just want to do this more active

20:27:45 [jwls29] can you tell us the answer to your ?

20:28:07 [Lorena] reoviridae , picorna and calci

20:28:20 [jwls29] yes

20:28:37 [Lorena] sure

20:29:10 [Lorena] a DNA in a bacteria can be chromosomal (its own) , plasmid and bacteriophage

20:29:50 [jwls29] ty

20:30:22 [Lorena] what do you want to discuss first virology or bacterial genetics?

20:30:28 [Lorena] or mixed?

20:30:31 [jwls29] virology

20:30:38 [crusher] genetics

20:30:38 [jwls29] we can do mixed

20:31:01 [Lorena] ok

20:31:46 [Lorena] what is transformation?

20:32:50 [crusher] dead dna fragments of one bacteria taken by other bacteria into its DNA

20:33:15 [Lorena] yes

20:33:15 [jwls29] transformation is gene uptake by a recipient cell of naked from a donor cell

20:34:10 [Lorena] very good, for doing this the bacteria has to be competent

20:35:06 [crusher] wht is transduction

20:35:23 [Lorena] after the bacteria takes the dna , what happen inside with this DNA and the bacteria genome?

20:35:52 [Lorena] transdcution is also tranfer of dna from a donor to a recipient using a bacteriophage

20:36:04 [jwls29] transfer of info from a donor to a recipient via a bacteriophage

20:36:23 [Lorena] the bacteriophage is the "transductor"

20:37:33 [crusher] yes via bacteriophages which are the bactetial viruses

20:37:51 [Lorena] phages can be lytic or lysogenic...explain the lytic one

20:38:33 kiranadi enters this room

20:38:54 [Lorena] hi kiran

20:40:14 [Lorena] the lytic phage is thenone that infect the bacteria and lyses it at the end of the cycle

20:40:30 [crusher] gene product that make bacteria less pathogewnic called lytic

20:41:10 [crusher] n doesnot make bactera pathogenic

20:41:32 [Lorena] no, because it destroys it

20:42:32 [crusher] and lysogenic make bacteria more pathogenic and enhance virulence

20:42:33 [Lorena] and lysogenic is the one that gets integrated in the chromosome

20:42:55 [ninadnashua] ok

20:43:44 [Lorena] and replicates with the chromosome so it can be passed to the daughters

20:44:36 [crusher] eg are O..antigen of salmonella B botulinium toxin D=diptheria toxin

20:44:59 [Lorena] yes , good one chrush

20:45:17 [crusher] these are pathogenic factors of lysogenic conversion

20:45:47 [Lorena] sometimes the lysogenyc phage can become lytic ...when does this happen?

20:46:50 [crusher] when it looses its virulence

20:47:38 [Lorena] it happens in adverse conditions like heat, UV radiation, etc the phage turns into lytic one and destroys the cell

20:47:54 [Lorena] and go somewhere else , more comfortable

20:48:21 [crusher] e,g if these toxin gey killed ..or destroyed

20:48:41 [Lorena] it is called induction

20:50:08 [Lorena] what is conjugation?

20:50:52 [crusher] transfer of plasmid from one bac to another by using pilli

20:51:28 [Lorena] yes

20:52:00 [Lorena] one has to be a donor (male) and the reciopient has to be female (absence of pillus)

20:52:48 [crusher] yes

20:53:06 [Lorena] why a mutation that might be normally recessive will always be expressed in bacteria?

20:54:59 [Lorena] in humans , a recessive mutation wont be expressed because we have 2 genes , 2 sets of genes ...one will be normal so no expression

20:55:12 [Lorena] but in bacteria

20:55:20 [Lorena] they are haploids

20:55:30 Hmmmmmm enters this room

20:55:46 [Lorena] hi hmmmmmmm

20:55:48 [crusher] wow good one lorena

20:56:00 [Hmmmmmm] hi lor

20:56:42 [Lorena] thanks

20:57:28 [crusher] what are insertion sequences??

20:57:32 [Hmmmmmm] so what did i miss

20:58:09 [Lorena] which one is sensitive to nucleases? therefore not very effective .... transformation, transduction, conjugation?

20:58:44 [jwls29] transformation

20:58:45 [Hmmmmmm] conjugation?

20:58:52 [Lorena] we are discusing bacterial genetics and virology hmmmm

20:59:06 [Hmmmmmm] ok thanks lor

20:59:10 [Lorena] transformation is right

20:59:47 [crusher] why lorena

20:59:53 [Hmmmmmm] can u explain please?

21:00:29 [Lorena] because it is taken by a recipient cell of naked DNA from a donor cell

21:01:11 [Hmmmmmm] oh ok

21:01:15 [Hmmmmmm] thanks

21:01:21 [Lorena] the naked DNA is sensitive to nucleases , remember in eukaryotes is usually protected by histones

21:02:14 [crusher] insertion sequences where the bacterial chromosomes integates in male cell

21:02:24 [crusher] donar cell

21:03:15 [Hmmmmmm] crush these sequences are inserted using what???? transformation?

21:03:37 [Lorena] transduction

21:04:12 [Hmmmmmm] im confused (im sorry)but where does transformation fit??

21:04:16 [Lorena] no, sorry it is conjugatioon

21:04:26 [crusher] plasmind==extra piece of chromosme inserted

21:04:38 [crusher] in conjugations

21:04:52 [crusher] imple word places where plasmid get into

21:05:02 [Lorena] transformation is the one that is sensitive to nucleases hmmmmm

21:05:46 [Hmmmmmm] hey ninadnashua.... , jwls29 *sorry im kinda sleepy

21:06:10 [ninadnashua] hi hmmmm

21:06:13 [jwls29] it's ok

21:06:58 [Hmmmmmm] lor i understand they are sensitive to nucleases but my q is where do they fit in????? like conjugation is bacteria to bac.. etc what is transformation invovle?

21:08:03 [Lorena] oh ok, transformation is uptake of DNA from a donor

21:08:24 [Lorena] the donor has naked DNA (it can be a dead bacteria in the environment)

21:08:42 [crusher] from dead bacteria

21:08:50 [Hmmmmmm] ok thats what i wanted to know ...thanks lor

21:08:56 [Hmmmmmm] thanks crush

21:09:07 [Lorena] yw

21:09:17 [crusher] n transduction transfer using bacteriophage

21:09:38 [crusher] bacteriophage ==bacterial virus

21:10:45 [Lorena] virus that causes pandemics due to its genetic drift and shift?

21:11:06 [crusher] H.influnza

21:11:08 [ninadnashua] inflenza

21:11:18 [Lorena] yes

21:11:41 [Hmmmmmm] crush isnt h.influ a bacteria

21:11:59 [crusher] uts influnza A

21:12:05 [Lorena] yes

21:12:13 [crusher] sorry

21:12:49 [Lorena] yes, segmented virus are more prones to mutations

21:12:50 [Hmmmmmm] a new born with respiratory insufficieny what most common virus do u think of?

21:13:10 [crusher] RSV

21:13:10 [jwls29] RSV

21:13:20 [Lorena] RSV

21:13:20 [Hmmmmmm]

21:13:47 [Lorena] treatment for RSV?

21:13:53 [ninadnashua] ya

21:13:54 [Hmmmmmm] what bout meningitis?

21:14:42 [Lorena] listeria monocytogenes, strept pneumoniae , E coli

21:15:04 [jwls29] ribivarin

21:15:23 [jwls29] agree with lorena

21:15:29 [Hmmmmmm] lor i asked newborn...ur rite bout 2

21:15:53 [Hmmmmmm] but MC is strep agalactaie

21:15:54 [ninadnashua] strpt agalactiae

21:16:01 [Hmmmmmm] then its ecoli and listeria

21:16:10 [Hmmmmmm] good ninadnashua

21:16:23 [Lorena] ok

21:16:28 [Lorena] thanks

21:16:30 [Hmmmmmm] strep pneumo come after 6months

21:16:34 [ninadnashua] thanks

21:16:39 [Hmmmmmm] np

21:16:59 [Hmmmmmm] can someone tell me the MOA of ribivarin..im not sure

21:17:02 [Lorena] adults is s.pneumoniae and neisseria meningitidis

21:17:21 [Hmmmmmm] good lor

21:17:30 [ninadnashua] ya

21:17:34 [Lorena] it inhibits RNA transcription

21:18:00 [Hmmmmmm] thanks

21:18:35 [Lorena] yw

21:19:11 [Hmmmmmm] what antibody u see in the window phase in a patient with Hep B infection

21:19:20 [Lorena] virus that is not a retrovirus but has reverse transcriptase?

21:19:35 [Lorena] core

21:20:06 [jwls29] HBcAB

21:20:17 [Hmmmmmm] any one else wana try this

21:20:27 [Hmmmmmm] ninadnashua and crush?

21:20:28 [Lorena] coreAg

21:21:20 [Hmmmmmm] yes its core.....good lor and jwls....

21:21:29 [crusher] window pahse only core ABb

21:21:35 [Hmmmmmm] yes

21:21:39 [Hmmmmmm] good crush

21:21:58 [crusher] are we done with genetics?

21:22:13 [Hmmmmmm] if a patient has anti hbs at 8months after hep B infecition what does that mean?

21:22:35 [Lorena] if you have more q's go ahead crush

21:22:37 [jwls29] chronic infection

21:22:50 [Lorena] chronicity

21:23:06 [Lorena] what is window period?

21:23:08 [crusher] HBS what antigen or AB

21:23:45 [Hmmmmmm] actually it immunity....if u see antigen then u see chronicity...can any one confirm this?

21:24:00 [Hmmmmmm] crush i was asking for ab

21:24:06 [crusher] iye sits immunity

21:24:20 [Hmmmmmm] ok ty

21:24:23 [Lorena] HBsAg= chronicity HBsAb=immunity ...thanks hm and crush

21:24:44 [Hmmmmmm] my pleasure

21:24:54 [jwls29] yes....you are right hmmm

21:25:23 [Hmmmmmm] ty jwls...its a pretty well tested fact..so doesnt hurt to make sure

21:25:37 [crusher] window only surface Ab present,,core Ab has not appear yet

21:25:58 [crusher] ooops i said opp

21:26:05 [Hmmmmmm] no no crush

21:26:09 [Hmmmmmm] yea

21:26:13 [Hmmmmmm]

21:26:44 [Hmmmmmm] what bout if u see HbeAg?

21:26:52 [Hmmmmmm] what does that tell u

21:26:59 [Lorena] window period is at the end of detection of HBsAg and before aparition of HBsAb

21:27:16 [Lorena] HBeAg means high infectivity

21:27:26 [Hmmmmmm] yes lor ur rite

21:27:47 [Lorena] thats when you order the core one

21:27:51 [Hmmmmmm] HBeAg means eeeeeeeeeeeeeeeeeeeeeee run away from teh patient...he will infect u

21:28:08 [Lorena] lol

21:29:39 [Hmmmmmm] heeh is everyone alive?

21:29:51 [Lorena] yep

21:30:03 [jwls29] i'm here

21:30:12 [Lorena] spot test, what does it detect?

21:30:36 [Lorena] mono spot test

21:31:04 [Hmmmmmm] not sure

21:31:13 [jwls29] mononucleosis

21:31:19 [jwls29] heterophile antibodies

21:31:44 [Lorena] yes, very good

21:31:56 [Hmmmmmm] thanks jwls

21:32:11 [Lorena] why is mononucleosis called kissing disease?

21:33:28 [Hmmmmmm] a patient with aids has a purple spot on his heel...keeps growning...and biopsy reveals spindle shaped cells with dark nuclie and abnormal mitotic bodies...what virus is it assosiciated with?

21:34:08 [Lorena] HV 8

21:34:13 [Hmmmmmm] hmm i always thought mumps was the kissing disase

21:34:21 [Hmmmmmm] yes good lor

21:34:32 [jwls29] herpes 8

21:34:53 [Hmmmmmm] good jwls

21:35:30 [Hmmmmmm] a female gets a pap smear done and pahtlogist sees dysplasia.....what virus associated with that ?

21:35:49 [Lorena] HPV 16, 18

21:35:54 [jwls29] hpv 16 and 18

21:36:22 [Lorena] what is the MOA of this virus to cause cancer?

21:36:54 [Hmmmmmm] good jwls and lor

21:37:51 [Lorena] it is a nasty little virus as <a target=new HREF=http://www.amazon.com/exec/obidos/external-search?tag=valuetheplace-20&keyword=Goljan&mode=books>Goljan</A> says

21:37:56 [jwls29] some strains have 2 genes that inactivate the tumor suppressor genes

21:37:56 [Lorena] oppsss

21:38:04 [Lorena] sorry about that

21:38:25 [Hmmmmmm] no no its ok...as long as the virus is nasty not gol jn

21:39:01 [Lorena] yes jwls : porteins E6 and E7 inactivates tumor supresor genes P53 and Rb

21:40:13 [jwls29] ok

21:40:24 [Lorena] virus implicated in Guillain Barre?

21:41:10 [Hmmmmmm] no idea...i remember i was in previous chat

21:42:00 [Lorena] influenza A, B..also a bacteria can cause it ...which one is that?

21:42:24 [jwls29] campylobacter

21:42:40 [Lorena] yep

21:43:06 [Hmmmmmm] hey lor whats for tomorow?

21:43:36 [Lorena] i dont know.... i just know that for friday is HIV and i am definitely coming

21:44:17 [Hmmmmmm] ok cuz im really tired and i didnt prepare for today..so i will see u tomorow

21:44:28 [Lorena] tomorrow it is clinical infectious or somethign like that

21:44:33 [jwls29] hey

21:44:36 [jwls29] hmmmm

21:44:43 [Hmmmmmm] sorry for the quick departure but thanks lor , jwls and ninadnashua

21:44:46 [Hmmmmmm] yea?

21:44:52 [jwls29] tomorrow is Clinical Infectious Disease;

21:45:09 [Hmmmmmm] yes that i wana attend

21:45:10 [Lorena] thanks for coming hmmmm , it was nice discussing with you

21:45:11 [jwls29] comparative micro and flow sheets

21:45:16 [Hmmmmmm] cuz it ties it all up

21:45:30 [Lorena] yes true , i will come too

21:45:30 [jwls29] hopefully we'll have more people

21:45:39 [Lorena] i will post the transcript

21:45:43 [Hmmmmmm] ty lor its a pleasure..so i wasnt more preped...but tomorow i will be

21:45:54 [Hmmmmmm] bye jwls and ty

21:45:57 [Hmmmmmm] bye lor

21:46:05 [Lorena] posting the transcriopt help people to see what we discussed and what we covered or not

21:46:10 [jwls29] bye hmmm

21:46:34 [Lorena] bye hmmm see you tomorrow

21:47:20 [Lorena] major cause of croup?

21:47:41 [jwls29] parainfluenza

21:47:50 [Lorena] yes

21:48:10 [jwls29] major cause of epiglottitis?

21:48:38 [Lorena] parainfluenza too?

21:48:56 [jwls29] i think it's influenza

21:49:22 [Lorena] ok

21:50:27 [Lorena] the fact that virus have enveloped or no tell you also about the course of the disease.... how can that be explained?

21:50:38 [jwls29] h flu

21:51:27 [jwls29] we said that enveloped were more susceptible to detergents and things to destroy it

21:51:37 [Lorena] yes

21:51:54 [Lorena] and also the realease of the virus

21:52:28 [Lorena] naked virus destroy the cell so no persistent infections -for example hepatitis A-

21:52:45 [Lorena] but enveloped virus are released by budding

21:52:53 [jwls29] yes

21:53:14 [Lorena] so cells aren't destroyed and may produce virus and lead to chronicity -hep B and C-

21:53:37 [jwls29] very good

21:53:41 [jwls29] thank you

21:54:08 [Lorena] what virus can produce aplastic crises in sickle cell patients?

21:54:31 [jwls29] B19

21:54:34 [jwls29] parvo

21:55:12 [Lorena] yes...do you know why not in normal people?

21:55:47 [jwls29] b/c of the mature rbc's

21:55:54 [jwls29] i'm guessing here

21:56:08 [jwls29] i know that it affects only immature rbc's

21:56:12 [Lorena] yes very good, mature RB cells dont have a nucleus

21:56:46 [Lorena] it produces aplastic crises because it is a naked virus so destroys the RBC when it is reeased

21:58:34 crusher enters this room

21:58:46 [Lorena] welcome back crush

21:59:07 [crusher]

21:59:47 [Lorena] one of the more serius complication sof mononucleosis?

22:00:07 [crusher] burkit lymphoma

22:00:21 [Lorena] yes

22:00:33 [Lorena] and in the acute phae?

22:00:40 [Lorena] phase

22:01:31 [crusher] kissing disease i think actue lymphadenitis?

22:02:09 [Lorena] yes

22:02:22 [Lorena] but the most serius one is spleen rupture

22:02:29 [Lorena] i mean in acute phase

22:02:46 [crusher] ya tahts why pat advis enot take part in contact sports

22:03:08 [Lorena] yes

22:04:38 [Lorena] tretament for CMV?

22:05:00 [jwls29] ganciclovir

22:05:09 [crusher] Gancyclovir for CMV retinitis

22:05:20 [Lorena] yes

22:05:22 [crusher] and Acyclovir in general

22:05:29 [Lorena] why not acyclovir?

22:05:52 [jwls29] b/c they lack thymidine kinase needed for the drug

22:05:55 [crusher] acyclovir require thymidine

22:06:35 [Lorena] yes and CMV doesnt have thymidine kinase so it cannot activate the drug so it is not useful for CMV

22:06:43 [Lorena] very good

22:07:44 [Lorena] and when the treatment is not succesful with gancyclovir (fior CMV ) then foscarnet

22:08:03 [jwls29] yes

22:08:38 [crusher] what are transposons??

22:09:07 [Lorena] sequences of DNA that can jump

22:09:32 [crusher] whats its use?

22:10:04 [Lorena] they have genes that code for the jumping capacity and also other genes that can carry resistance to antibiotics

22:11:51 [crusher] yes imp role in buliding drug resistance plasmid.....may move to chromosome.

22:12:51 [Lorena] what is the difference with an insertion sequence?

22:13:03 [crusher] what are insertion sequences

22:13:22 [Lorena] we are thinking alike

22:13:29 [crusher] heheh

22:14:02 [Lorena] insertion sequence is also a piece of DNA but only carry genes necessary for jumping and no other genes

22:15:38 [crusher] also insertion sequence form direct repat on eachh site of transposons

22:16:25 [Lorena] yes

22:17:01 [crusher] they are on terminal ends in indiderct repeat

22:18:38 [jwls29] well folks

22:18:43 [jwls29] time to call it a night

22:18:50 [jwls29] i will see you all tomorrow

22:18:54 [crusher] insertion sequence==terminal indirect repeat

22:18:58 [jwls29] thanks for the chat

22:19:01 [Lorena] see yuo tomorrow jwls

22:19:16 [jwls29] bye

22:19:16 [crusher] hile transposons=additional genes

22:19:37 [Lorena] yes

22:19:56 [crusher] bye jwel

22:21:58 [Lorena] what is the only of the tranfer of DNA in bacteria that doesnt require recombiantion?

22:22:37 [crusher] transduction/

22:22:57 [Lorena] yes

22:23:02 [Lorena] excellent

22:23:30 [Lorena] what is an R factor?

22:24:52 [crusher] what is that lor

22:25:20 [Lorena] it is a plasmid , that carries resistance factors

22:25:40 [Lorena] resistance genes for drugs i meant

22:25:54 [crusher] ok thanks

22:26:20 [Lorena] i think we covered quite a bit crush, what do you think?

22:26:46 [crusher] yes lorna

22:27:03 [Lorena] it is time for me to go, it was a pleasure to talk to you

22:27:08 [crusher] ii think we cover major point on genetics

22:27:24 [Lorena] are you coming tomorrow?

22:27:29 [crusher] same is here lorena

22:27:46 [crusher] i willtry my best

22:28:15 [Lorena] ok, hopefyully we will chat tomorrow too , see you and take care

22:28:39 [crusher] take care n goodnight

22:28:39 [Lorena] i will post this now

22:28:42 [Lorena] byeeee

[Anonymous]

Hi, Lorana,

Would you please post the HIV chat transcript? I couldn't log on last night.
Thanks

IMG0319

[Lorena]

sorry i could make it to the chat yesterday.

Next chat is Goljan pathology so i hope lot of people go with questions to make it more active. It is a really important topic and discuss with other people helps a lot.

I am not able to attend everyday thats when i dont post the transcripts.