A scientist appearing at the murder trial of Gerard Baden-Clay has given expert evidence that Allison, whose body was found on a creek bank, did not drown.

Baden-Clay, 43, a former real estate agent, has pleaded not guilty in the Supreme Court to killing his wife in April 2012.

The body of the 43-year-old mother of three was found on a creek bank under a bridge by a kayaker about 10 kilometres from the couple's Brookfield home, 10 days after she was reported missing.

Giving evidence by telephone, microscopic algae expert Dr Jacob John told the court he was given water samples from Kholo Creek, the site where Allison was found, as well as parts of her liver and bone.

Dr John said the water sample carried "a bloom" of diatoms (microscopic algae).

Given diatoms can remain in the bone marrow, Dr John said they would have provided "inevitable evidence for drowning".

"If she [Allison] had drowned in the water, I would definitely expect to see a couple of species of diatoms," he said, adding that he was unable to find any signs of the algae in the organ samples provided.

"My straight conclusion is that ... the subject concerned did not drown in Kholo Creek or anywhere," he said.

Also giving evidence at the trial today was Associate Professor James Wallman, a forensic entomologist from New South Wales.

Professor Wallman told the court, via telephone, he was sent samples from police to identify insect specimens, to see if he could establish a minimum time since the death of Allison and also determine whether her body had been submerged in the creek.

He said he was given fly eggs, fly maggots, adult flies and adult beetles which were found on Allison's body.

Professor Wallman said the growth of the insects implied it was at least three to four days since death, adding that slow temperatures could slow down growth, which "could be" consistent with the victim being dead for 11 days.

Unlike Dr John, Professor Wallman could not determine whether the victim had drowned.

"I couldn't reach a conclusion one way or the other," he said.

MP Bruce Flegg tells of request for $400K loan

Earlier today, former Queensland Government minister Bruce Flegg told the court Gerard Baden-Clay had asked him for a loan of $400,000.

Sorry, this video has expired Former Qld minister Bruce Flegg gives evidence at Gerard-Baden Clay's murder trial ( Leonie Mellor )

Last Thursday, Susanne Heath, a friend of the MP, testified that Baden-Clay had asked if Dr Flegg could lend him about $300,000.

Dr Flegg told the court this morning of a meeting with Baden-Clay in mid-December 2011, where the accused said he needed to raise $400,000.

He said Baden-Clay had told him he was not looking for an equity partner and wanted a loan.

Dr Flegg told the court Baden-Clay said he owed money to his business partners who were leaving.

He also told the court he has known Baden-Clay for a number of years and their relationship was "very friendly".

Dr Flegg said he had some social contact with Baden-Clay, mainly through Chamber of Commerce and Christmas functions.

He told the court that in March 2012 he had a message from Baden-Clay to call, but he was busy so he got Ms Heath to call the accused.

Dr Flegg said Ms Heath told him Baden-Clay again asked for money.

He said he later called Baden-Clay and told the accused that Ms Heath had relayed his response to the request.

Dr Flegg said Baden-Clay's loan request "was probably out of the ordinary, but not dramatically left field".

When asked if Baden-Clay had ever asked for money on other occasions, Dr Flegg replied: "No, no."

Dr Flegg heard a 'female scream'

Dr Flegg also said on the night of April 19, 2012, he heard what he would describe as a female scream.

"I'm quite certain it was a female voice," he said.

"It was a single, reverse crescendo in volume, tapering off, and what I would describe as having an involuntary quality.

"[The scream] very strongly suggested a reduced level of consciousness."

Dr Flegg said he heard exactly the same sound about two to three minutes later.

He said he had no doubt about what he heard, but was not sure about how far away it was.

Dr Flegg said he was on the phone to Ms Heath when heard the scream, with his phone showing it to be 10:58pm.

"I said, 'did you hear that?'" he told the court.

Dr Flegg said he went out the front door to see if something was around his house.

"I heard nothing else that evening and that'd probably be the case most evenings," he said.

Under cross-examination, Dr Flegg said his house was at least one kilometre from the Baden-Clay home.

Dr Flegg told the court he "would be extremely surprised" if the noises he heard came from Baden-Clay home.

Friends speak of loans made to Baden-Clay

Friend Robert Cheesman told the court he lent Baden-Clay $90,000 to help him with his business.

"The business was clearly in trouble but I saw it had a way out," Mr Cheesman said.

Mr Cheesman said there was meant to be a formal agreement but they never got around to it.

He said Baden-Clay was meant to pay 10 per cent interest and that he got interest payments for three or four months.

Mr Cheesman said he never got the principal sum back and by April 2012, Baden-Clay still owed him $90,000.

Mr Cheesman also said he had not known about his friend's affair with Toni McHugh.

Under cross-examination, Mr Cheesman said for the first six months, he approved every expense that went out of the business.

"Personally [Baden-Clay] was secure, but the businesses was where his risk was," Mr Cheesman said.

Another friend of Baden-Clay, Stuart Christ, told the court their children went to same school.

"We've been very close over the years, but in recent years probably not as close," Mr Christ said.

The court heard Mr Christ and his wife lent Baden-Clay $90,000 in 2011 because his business was not going so well.

Mr Christ said they paid the money into Gerard and Allison's joint bank account.

He said Baden-Clay was due to pay the $90,000 principal, plus $90,000 in interest, and that they received three payments.

Mr Christ was asked if he was aware of Gerard Baden-Clay's relationship with Ms McHugh.

"I was not," he replied.

Mr Christ said he may have met Ms McHugh, but did not recall her.

He told the court Allison became more involved in the business in late 2011 "and that gave us a lot of comfort".

Mr Christ said Gerard Baden-Clay asked for more money at various times in mid-2011, but he never gave it.

He also said he was aware of Allison's depression.

Mr Christ said sometimes Allison would answer the door, sometimes not.

"[It was] no big deal, it was Allison," he said.

Meanwhile, Peter Cranna testified he has been a friend of Baden-Clay for over 20 years and they were in each other's bridal parties.

Mr Cranna said he lent Baden-Clay $45,000, $12,000, $50,000, $24,000 and $19,000, between February 2006 and February 2011.

He told the court as of April 2012 Baden-Clay owed him $96,000.

Mr Cranna also said he never knew Ms McHugh and only found out about the affair after Allison went missing.