Proteomic analysis of digestive tract peptidases and lipases from the invasive gastropod Pomacea canaliculata

Background

The invasive gastropod Pomacea canaliculata has received great attention in the last decades as a result of its negative impact on crops agriculture, yet knowledge of their digestive physiology remains incomplete, particularly the enzymatic breakdown of macromolecules such as proteins and lipids.

Results

Discovery proteomics revealed aspartic peptidases, cysteine peptidases, serine peptidases, metallopeptidases and threonine peptidases, as well as acid and neutral lipases and phospholipases along the digestive tract of P. canaliculata. Peptides specific to peptidases (139) and lipases (14) were quantified by targeted mass spectrometry. Digestion begins in the mouth via diverse salivary peptidases (nine serine peptidases; seven cysteine peptidases, one aspartic peptidase and 22 metallopeptidases) and then continues in the oesophagus (crop) via three luminal metallopeptidases (Family M12) and six serine peptidases (Family S1). Downstream, the digestive gland provides a battery of enzymes composed of aspartic peptidase (one), cysteine peptidases (nine), serine peptidases (12) and metallopeptidases (24), including aminopeptidases, carboxypeptidases and dipeptidases). The coiled gut has M1 metallopeptidases that complete the digestion of small peptides. Lipid extracellular digestion is completed by triglyceride lipases.

Conclusion

From an integrative physiological and anatomical perspective, P. canaliculata shows an unexpected abundance and diversity of peptidases, which participate mainly in extracellular digestion. Moreover, the previously unknown occurrence of luminal lipases from the digestive gland is reported for the first time. Salivary and digestive glands were the main tissues involved in the synthesis and secretion of these enzymes, but plausibly the few luminally exclusive peptidases are secreted by ventrolateral pouches or epithelial unicellular glands. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Cloning of a Genomic DNA Encoding Caffeoyl-coenzyme A 3-<Emphasis Type="Italic">O</Emphasis>-methyltransferase of Citrus

In recent studies, we found that Apll (a PthA homologue) bound to three citrus proteins. Amino acid sequence analysis revealed that one of the target proteins was homologous to that of S-adenosyl-l-methionine : trans-caffeoyl-coenzyme A 3-O-methyltransferase (CCoAMT), an enzyme which is specific for the substrate trans-caffeoyl-CoA and catalyzes the synthesis of trans-feruloyl-CoA. From the consensus nucleotide sequences of CCoAMT genes, primers were chosen for PCR amplification of this gene from citrus total DNA. Two selected DNA fragments of 1.0 kb and 2.0 kb were obtained. These fragments were used as the probe to screen a citrus library. One clone, pCCl00, contained a 1.0-kb SalI fragment that hybridized to the probes. The nucleotide sequence of this fragment was determined in both directions. In this fragment, there was an open reading frame of 232 amino acids interrupted by an intron of 106 nt, and the deduced amino acid sequence had 95.9% homology to tobacco CCoAMT. Southern blot analysis of total citrus DNA showed that four EcoRI fragments hybridized to the probes, suggesting the presence of more than one copy of CCoAMT in the citrus DNA. Received 4 November 1999/ Accepted in revised form 26 November 1999     

Inheritance of resistance to four cucurbit viruses in Cucurbita moschata

Cucurbita moschata cv. Nigerian Local has been used as a source of resistance to Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), Papaya ringspot virus W (PRSV-W) and Cucumber mosaic virus (CMV) in breeding both Cucurbita moschata and Cucurbita pepo. We used the F₁, F₂ and BC₁ generations derived from the cross C.-moschata cv. Waltham Butternut × Nigerian Local to study the inheritance of resistance to each of the viruses. We confirmed monogenic dominant resistance to ZYMV previously attributed to Zym, and we report monogenic dominant resistance to WMV and CMV which we propose to designate Wmv and Cmv, respectively. A single recessive gene, which we propose to designate prv, controls resistance to PRSV. DNA samples were extracted from a Waltham Butternut BC₁ F₁ population screened with ZYMV and analyzed using randomly amplified polymorphic DNA markers. No RAPD markers linked to ZYMV resistance were found. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development of a real-time SYBR Green PCR assay for the rapid detection of Dermatophilus congolensis

Methods such as real time (RT)-PCR have not been developed for the rapid detection and diagnosis of Dermatophilus (D.) congolensis infection. In the present study, a D. congolensis-specific SYBR Green RT-PCR assay was evaluated. The detection limit of the RT-PCR assay was 1 pg of DNA per PCR reaction. No cross-reaction with nucleic acids extracted from Pseudomonas aeruginosa, Mycobacterium tuberculosis, Staphylococcus aureus, or Austwickia chelonae was observed. Finally, the RT-PCR assay was used to evaluate clinical samples collected from naturally infected animals with D. congolensis. The results showed that this assay is a fast and reliable method for diagnosing dermatophilosis.     

Risk factors associated with reproductive performance in small-scale dairy farms in Mexico

Several studies suggest that reproductive performance in small-scale dairy farms is low reducing the farms’ profitability. Therefore, identifying risk factors associated with low reproductive performance is a key step to implement an improved reproductive management program. Accordingly, the aim of the present study was to identify the main risk factors affecting the reproductive performance of cows in small-scale dairy farms. Ninety-six dairy farms were incorporated into this study, and data from 1263 lactations were collected with different events as potential risk factors. Logistic regression models were used to assess the association (odds ratio, OR) and impact (population attributable fraction, PAF) between the potential risk factors and the reproductive variables. The main risk factors associated with assisted calving were male calf and primiparous cows (OR?=?1.7, PAF?=?0.315 and OR?=?1.5, PAF?=?0.131, respectively), while for retained fetal membranes (RFM) were assisted calving and abortion (OR?=?4.5, PAF?=?0.440 and OR?=?8.1, PAF?=?0.239, respectively). The main risk factors for days to first service over 70 days in milk were low body condition score at calving (BCS?≤?2.5) and primiparous cows (OR?=?2.2, PAF?=?0.285 and OR?=?1.4; PAF?=?0.096, respectively), while for days open over 110 days in milk were low BCS at calving (BCS?≤?2.5) and primiparous cows (OR?=?1.7, PAF?=?0.213 and OR?=?1.4; PAF?=?0.096, respectively) The main risk factor for non-pregnant cows at first service was RFM (OR?=?1.7; PAF?=?0.059). In conclusion, assisted calving, male calf, BCS?≤?2.5 and RFM were the main risk factors associated with reduced reproductive performance in small-scale dairy farms in tropical and subtropical regions of Mexico.

     

Composite Likelihood Inference for Multivariate Gaussian Random Fields

In the recent years, there has been a growing interest in proposing covariance models for multivariate Gaussian random fields. Some of these covariance models are very flexible and can capture both the marginal and the cross-spatial dependence of the components of the associated multivariate Gaussian random field. However, effective estimation methods for these models are somehow unexplored. Maximum likelihood is certainly a useful tool, but it is impractical in all the circumstances where the number of observations is very large. In this work, we consider two possible approaches based on composite likelihood for multivariate covariance model estimation. We illustrate, through simulation experiments, that our methods offer a good balance between statistical efficiency and computational complexity. Asymptotic properties of the proposed estimators are assessed under increasing domain asymptotics. Finally, we apply the method for the analysis of a bivariate dataset on chlorophyll concentration and sea surface temperature in the Chilean coast.