instruction:
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.
question:
Bovine renal brush-border membrane vesicle aminopeptidase N at various stages of purity was treated with two bifunctional cross-linking agents. A pattern of emergence of higher molecular weight forms was observed. By using a cleavable cross-linker, aminopeptidase N was shown to cross-link both to itself and to its breakdown products as well as to dipeptidyl peptidase IV. Using this technique it was possible to identify three of the breakdown products as 45 kDa, 66 kDa and 95 kDa peptides. N-terminal amino acid sequence analysis was used to define the precise cleavage points for the bovine renal aminopeptidase N breakdown products. The short amino acid sequences obtained show strong sequence similarity with the human intestinal and rat kidney aminopeptidase N.
answer:
The oligomeric structure of renal aminopeptidase N from bovine brush-border membrane vesicles


question:
Among RNA viruses, the order Nidovirales stands out for including viruses with the largest RNA genomes currently known. Nidoviruses employ a complex RNAsynthesizing machinery comprising a variety of non-structural proteins (nsps). One of the postulated drivers of the expansion of nidovirus genomes is the presence of a proofreading 3 -to-5 exoribonuclease (ExoN) belonging to the DEDDh family. ExoN may enhance the fidelity of RNA synthesis by correcting nucleotide incorporation errors made by the RNA-dependent RNA polymerase. Here, we review our current understanding of ExoN evolution, structure, and function. Most experimental data are derived from studies of the ExoN domain of coronaviruses (CoVs), which were triggered by the bioinformatics-based identification of ExoN in the genome of severe acute respiratory syndrome coronavirus (SARS-CoV) and its relatives in 2003. Although convincing data supporting the proofreading hypothesis have been obtained, from biochemical assays and studies with CoV mutants lacking ExoN functionality, the features of ExoN from most other nidovirus families remain to be characterized. Remarkably, viable ExoN knockout mutants were obtained only for two CoVs, mouse hepatitis virus (MHV) and SARS-CoV, whose RNA synthesis and replication kinetics were mildly affected by the lack of ExoN function. In several other CoV species, ExoN inactivation was not tolerated, and knockout mutants could not be rescued when launched using a reverse genetics system. This suggests that ExoN is also critical for primary viral RNA synthesis, a property that poorly matches the profile of an enzyme that would merely boost longterm replication fidelity. In CoVs, ExoN resides in a bifunctional replicase subunit (nsp14) whose C-terminal part has (N7-guanine)-methyltransferase activity. The crystal structure of SARS-CoV nsp14 has shed light on the interplay between these two domains, and on nsp14's interactions with nsp10, a co-factor that strongly enhances ExoN activity in vitro assays. Further elucidation of the structure-function relationships of ExoN and its interactions with other (viral and/or host) members of the CoV replication machinery will be key to understanding the enzyme's role in viral RNA synthesis and pathogenesis, and may contribute to the design of new approaches to combat emerging nidoviruses.
answer:
The Curious Case of the Nidovirus Exoribonuclease: Its Role in RNA Synthesis and Replication Fidelity


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Background: Cryptosporidium spp. are zoonotic parasites responsible for diarrhoeal diseases in animals and humans worldwide. Cattle are the most common mammalian species in which Cryptosporidium is detected, with pre-weaned calves considered to be reservoirs for zoonotic C. parvum. In October 2013, severe diarrhoea was observed in 396 pre-weaned calves at a farm in the Ningxia Autonomous Region of Northwestern China. 356 of the infected calves died despite antibiotic therapy. Findings: 252 faecal samples were collected from the investigated farm. The identity of Cryptosporidium species was determined by polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) analysis, and by DNA sequence analysis of the small subunit (SSU) rRNA gene. C. parvum was subtyped using sequence analysis of the 60 kDa glycoprotein (gp60) gene. The highest infection rate of 83.3% (40/48) was seen in 2-3-week-old calves with diarrhoea, corresponding to the age at which animals died. Three Cryptosporidium species were identified, including C. parvum (n = 51), C. bovis (n = 1), and C. ryanae (n = 1). All C. parvum isolates were further identified as subtype IIdA15G1. Conclusions: Cryptosporidium parvum was likely to be most responsible for diarrhoea and death. This is the first report of a cryptosporidiosis outbreak caused by C. parvum IIdA15G1 in Chinese dairy cattle.
answer:

Cryptosporidiosis caused by Cryptosporidium parvum subtype IIdA15G1 at a dairy farm in Northwestern China