In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

[EX Q]: Background: SARS coronavirus (SARS-CoV) was identified as the etiological agent of SARS, and extensive investigations indicated that it originated from an animal source (probably bats) and was recently introduced into the human population via wildlife animals from wet markets in southern China. Previous studies revealed that the spike (S) protein of SARS had experienced adaptive evolution, but whether other functional proteins of SARS have undergone adaptive evolution is not known. We employed several methods to investigate selective pressure among different SARS-CoV groups representing different epidemic periods and hosts. Our results suggest that most functional proteins of SARS-CoV have experienced a stepwise adaptive evolutionary pathway. Similar to previous studies, the spike protein underwent strong positive selection in the early and middle phases, and became stabilized in the late phase. In addition, the replicase experienced positive selection only in human patients, whereas assembly proteins experienced positive selection mainly in the middle and late phases. No positive selection was found in any proteins of bat SARS-like-CoV. Furthermore, specific amino acid sites that may be the targets of positive selection in each group are identified. This extensive evolutionary analysis revealed the stepwise evolution of different functional proteins of SARS-CoVs at different epidemic stages and different hosts. These results support the hypothesis that SARS-CoV originated from bats and that the spill over into civets and humans were more recent events.
[EX A]: Differential stepwise evolution of SARS coronavirus functional proteins in different host species

[EX Q]: Human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) are important respiratory pathogens with similar symptomatology. The aim of this prospective birth cohort study was to identify risk factors for an hMPV or RSV infection during the first year of life in unselected healthy children. We followed 217 children from birth to 1 year of age. Nasal swabs and symptom diaries were collected monthly. Anti-hMPV and anti-RSV IgG antibodies by age 1 year were detected by ELISA, and nasal swabs were analysed for hMPV and RSV by RT-PCR. Logistic regression was used for risk factor analysis. Anti-hMPV IgG was found in 38 children (17.5%), and anti-RSV IgG in 172 children (79%). Risk factors for being anti-hMPV IgG-positive were: (1) being born in the spring (OR =2.36; 95% CI:1.06-5.27), and (2) having older siblings (OR=3.82; 95% CI:1.75-8.34). Risk factors for being anti-RSV IgG-positive were: (1) gestational age <38 weeks (OR=3.39; 95% CI:1.42-8.05), (2) increasing paternal age (OR=1.85 per 5 yrs; 95% CI:1.28-2.68), and (3) wall-to-wall carpeting (OR=3.15; 95% CI:1.29-7.68). Being born in the spring was associated with decreased odds of being anti-RSV IgG-positive (OR=0.27, 95% CI:0.09-0.85). Risk factors for RSV hospitalisation (n= 11) were: (1) older siblings (OR=4.49; 95% CI: 1.08-18.73) and (2) smoking in the household (OR=5.06; 95% CI: 1.36-18.76). Exclusive breastfeeding for the first 14 days of life protected against hospitalisation (OR= 0.21; 95% CI:0.06-0.79). In conclusion, this study identifies risk factors for mild and asymptomatic hMPV infections in infancy. Abbreviations hMPV human metapneumovirus RSV respiratory syncytial virus OR odds ratio PBS phosphate-buffered saline NPA nasopharyngeal aspirate RT-PCR reverse transcription-polymerase chain reaction ELISA enzyme-linked immunosorbent assay RT room temperature M-PBS PBS with 2% skim-milk powder HRP horseradish peroxidase TMB tetramethyl benzidine OD optical density SD standard deviation PDV Phocine Distemper Virus Eur
[EX A]: A community study of clinical traits and risk factors for human metapneumovirus and respiratory syncytial virus infection during the first year of life

[EX Q]: The intracellular expression of antibodies or antibody fragments (intrabodies) in different compartments of mammalian cells allows to block or modulate the function of endogenous molecules. Intrabodies can alter protein folding, proteinprotein, protein-DNA, protein-RNA interactions and protein modification. They can induce a phenotypic knockout and work as neutralizing agents by direct binding to the target antigen, by diverting its intracellular traffic or by inhibiting its association with binding partners. They have been largely employed as research tools and are emerging as therapeutic molecules for the treatment of human diseases as viral pathologies, cancer and misfolding diseases. The fast growing bio-market of recombinant antibodies provides intrabodies with enhanced binding specificity, stability and solubility, together with lower immunogenicity, for their use in therapy. This chapter describes the crucial aspects required to express intrabodies in different intracellular compartments of mammalian cells, their various modes of action and gives an update on the applications of intrabodies in human diseases.
[EX A]:
Intrabody Expression in Mammalian Cells