So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

The calpain system originally comprised three molecules: two Ca2+-dependent proteases, mu-calpain and m-calpain, and a third polypeptide, calpastatin, whose only known function is to inhibit the two calpains. Both mu- and m-calpain are heterodimers containing an identical 28-kDa subunit and an 80-kDa subunit that shares 55-65% sequence homology between the two proteases. The crystallographic structure of m-calpain reveals six "domains" in the 80-kDa subunit: 1). a 19-amino acid NH2-terminal sequence; 2). and 3). two domains that constitute the active site, IIa and IIb; 4). domain III; 5). an 18-amino acid extended sequence linking domain III to domain IV; and 6). domain IV, which resembles the penta EF-hand family of polypeptides. The single calpastatin gene can produce eight or more calpastatin polypeptides ranging from 17 to 85 kDa by use of different promoters and alternative splicing events. The physiological significance of these different calpastatins is unclear, although all bind to three different places on the calpain molecule; binding to at least two of the sites is Ca2+ dependent. Since 1989, cDNA cloning has identified 12 additional mRNAs in mammals that encode polypeptides homologous to domains IIa and IIb of the 80-kDa subunit of mu- and m-calpain, and calpain-like mRNAs have been identified in other organisms. The molecules encoded by these mRNAs have not been isolated, so little is known about their properties. How calpain activity is regulated in cells is still unclear, but the calpains ostensibly participate in a variety of cellular processes including remodeling of cytoskeletal/membrane attachments, different signal transduction pathways, and apoptosis. Deregulated calpain activity following loss of Ca2+ homeostasis results in tissue damage in response to events such as myocardial infarcts, stroke, and brain trauma.

The Calpain System

https://www.commed.vcu.edu/Chronic_Disease/2012/cochranrvwrschbias.pdf

The Cochrane Collaboration's tool for assessing risk of bias in randomised trials

The current outbreak of the novel coronavirus Covid-19 (coronavirus disease 2019; previously 2019-nCoV), epi-centered in Hubei Province of the People's Republic of China, has spread to many other countries. On January 30, 2020, the WHO Emergency Committee declared a global health emergency based on growing case notification rates at Chinese and international locations. The case detection rate is changing hourly and daily and can be tracked in almost real time on website provided by Johns Hopkins University [1] and other websites. As of early February 2020, China bears the large burden of morbidity and mortality, whereas the incidence in other Asian countries, in Europe and North America remains low so far.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/tmi.13383

The COVID-19 epidemic.

On December 12th 2019, a new coronavirus (SARS-Cov2) emerged in Wuhan, China, sparking a pandemic of acute respiratory syndrome in humans (COVID-19). On the 24th of April 2020, the number of COVID-19 deaths in the world, according to the COVID-Case Tracker by Johns Hopkins University, was 195,313, and the number of COVID-19 confirmed cases was 2,783,512. The COVID-19 pandemic represents a massive impact on human health, causing sudden lifestyle changes, through social distancing and isolation at home, with social and economic consequences. Optimizing public health during this pandemic requires not only knowledge from the medical and biological sciences, but also of all human sciences related to lifestyle, social and behavioural studies, including dietary habits and lifestyle. Our study aimed to investigate the immediate impact of the COVID-19 pandemic on eating habits and lifestyle changes among the Italian population aged ≥ 12 years. The study comprised a structured questionnaire packet that inquired demographic information (age, gender, place of residence, current employment); anthropometric data (reported weight and height); dietary habits information (adherence to the Mediterranean diet, daily intake of certain foods, food frequency, and number of meals/day); lifestyle habits information (grocery shopping, habit of smoking, sleep quality and physical activity). The survey was conducted from the 5th to the 24th of April 2020. A total of 3533 respondents have been included in the study, aged between 12 and 86 years (76.1% females). The perception of weight gain was observed in 48.6% of the population; 3.3% of smokers decided to quit smoking; a slight increased physical activity has been reported, especially for bodyweight training, in 38.3% of respondents; the population group aged 18–30 years resulted in having a higher adherence to the Mediterranean diet when compared to the younger and the elderly population (p < 0.001; p < 0.001, respectively); 15% of respondents turned to farmers or organic, purchasing fruits and vegetables, especially in the North and Center of Italy, where BMI values were lower. In this study, we have provided for the first time data on the Italian population lifestyle, eating habits and adherence to the Mediterranean Diet pattern during the COVID-19 lockdown. However, as the COVID-19 pandemic is ongoing, our data need to be confirmed and investigated in future more extensive population studies.

/pdf/eating-habits-and-lifestyle-changes-during-covid-19-lockdown-27svbjy20r.pdf

Eating habits and lifestyle changes during COVID-19 lockdown: an Italian survey.

Prevalence of hypercalciuria is markedly increased in patients
with calcium kidney stones, and recently it has been demon-
strated that the risk to produce stones is positively related with
the levels of calcium excretion in general population. The stone-
promoting effect of hypercalciuria depends on the unusually
high calcium concentrations in urine and tubular fluid, which fa-
vor calcium salt precipitation. However, the specific role of calci-
um in the pathogenetic pathway leading to stone formation has
not been elucidated and it is unclear whether initial events of
this process develop in tubules or in papillary interstitium.
Nephrocalcinosis occurs in the course of many hereditary or
acquired disorders having hypercalciuria as the common alter-
ation and can progressively damage kidney function. In spite of
the relevance of hypercalciuria for nephrocalcinosis, the specif-
ic effect of calcium in its development is yet unknown.
An increased frequency of hypercalciuria has also been
recorded among patients with arterial hypertension. It has
been hypothesized that a body calcium deficiency is induced
by hypercalciuria and leads to the elevation of blood pressure. This may be true in a subgroup of patients, while hypercalci- uria is likely to occur more commonly in patients with volume- dependent hypertension. Irrespective of its possible causal role, hypercalciuria may predict individual susceptibility to stones, nephrocalcinosis or
arterial hypertension. Measurement of 24 hour calcium excre-
tion could become an instrument to identify subjects predis-
posed to these disorders.

/pdf/kidney-complications-in-primary-hypercalciuria-wsw7ukfifv.pdf

Laura Soldati

Papers

Kidney complications in primary hypercalciuria